I did exactly this type of wind tunnel study for my final year project for my Mechanical Engineering Degree. The drag from the slightly REDUCED pressure behind the caravan/van/trailer/bluff body is called Form Drag. It is around 25% of total drag BUT the only efficient way to reduce it is to taper the rear shape. Like a wing or very very long VW beetle tail (3 to 4 times longer than its height!!) The rear scoop like shown does reduce drag (about 5%) but the additional drag of the scoop (about 10%) results in nett increase of drag by about 5%. I proved this by holding the scoop in position but not attached to the model in the wind tunnel. Then repeated with attached. Also, shape, angle of attack AND distance from the body were very sensitive and had optimal positions w.r.t. shape and angle
@@grimreaper6112 couldn't move it at all!!?? I towed a mini behind another mini (a framed). Low HP just means slower acceleration and lower top speed. Unless the van was the size/weight of a bus, then a Datsun could get it moving, albeit slowly
Hi John. I’m an Auto Mechanic and just spent the last 15 minutes in stitches. Thanks for that. I love the way you bring facts and logic into your argument. By the way have you seen the UK Top Gear boys take the piss out of caravans and caravaners? I’m sure you have. Very funny and worth a look if you haven’t seen it. Thanks again for the laughs.
Funny this should come up. I was driving back from Wollongong down the Hume today and found myself in the vicinity of a massive f-off caravan being towed by a Ford Ranger in the Raptor config. I was doing the speed limit and this chap was overhauling me at speed on the downhill side and disappearing...until I caught him in the hills again, where he'd be chugging up and losing momentum at a rate of knots. As I overtook him for the fiftieth time before turning off at Yass, I remembered your earlier video on towing dynamics and the risks of towing at top (legal) speed, without any travel left in the pedal for emergency death wobble rectification. Good times.
re: Setting it on fire. In QLD, any fire over 2 metres in any dimension requires a Permit, obtainable from your local Fire Warden (no charge). Nice one, John.
3:57 John, you hit the nail right on the head regarding the value of these expensive caravans (toilet towers). My neighbours across the road has one of these monstrosities which they use twice a year. As it's to large to store on their property, it goes to a storage shed in town until needed. When the owners get it out of storage, it's parked on the street blocking the better part of the road. They then spend 3 days cleaning it & stocking it with supplies, charging the batteries etc, before they make their "epic" trip (towing it with a 2021 Nissan Patrol) which is 2 hours away from home to make camp for a fortnight. During their fortnight away, they still call back home to mow the grass & do some cleaning. Then when they come back, they park it in the same spot, clean it inside & out and then store it away again. What is the point of owning a very large expensive towing toilet clogging up out highways? They would be better off at a resort & they'd still save money!
@@ewicky I think you misunderstood; my point was buying expensive things to use them so rarely that the owner would be better off without. Boats are often the same thing; best day is when you buy your boat; 2nd best day is when you sell it. Knew someone that had a boat, he finally sold it and bought a much-more used motorcycle as a cheaper toy.
Now if you could only explain to caravanners why they should use slow vehicle turnouts instead of speeding up when they've been doing 20km/h below the speed limit on a tight bendy road with a trail of pissed-off cars behind them for the last 15km, that would be great.
old mate laurie is now driving to that massive rock in central Australia to live under, after that roasting😅😂😅 love your work, the honesty is breathtaking👍👍👍
I recently towed 2400 kg with my Prado locally. As it had little fuel in it, was empty and I was rolling solo at 60kg, I’m sure all was good weight wise. It was a short 3km trip to my local mechanic with a non running van on a tandem. That right there was experience enough to tell me there’s no way I’d put a 2t van on the back and tour Australia. I felt bad enough holding up people in suburban Melbourne and I’ve got a V6.
Here in the US I see trucks with spoilers like you showed in the video. I am inclined to think the reason trucks aren't more aerodynamic in the back is because they have to be able to back up to a dock door and get an air tight seal in some cases.
Yeah his truck idea isn't 100% But here in Aus, there has been a few aero trailers made to success. But the loss of freight space to any aero designs canceled the financial benefits.
Good review John… loved your delivery as always. Hired a large caravan few years ago and towed with my Navara Ute, astonished of the amount of diesel used. Next one will be a small pop up just for the misses and me.
In my 3 decades of working in engineering, I've met many a Laurie. One conceived the idea to use the water flow in the downpipes when it was raining with a turbine to generate electricity to assist pumping that very same water up to the storage tank about 15m up the hillside.
Have you seen those marvelous downpipe water turbine generators on YT? They are often capable of producing up to 9 milli-Watts before becoming clogged with roof debris. Putting this abundant power source to use pumping huge volumes of water uphill should be a breeze.
It always amazes me how people think their $100 mod will make a vehicle much better and that none of the engineers working at the company that made the vehicle had thought about such an "ingenious" solution.
I know someone who bought the outback caravan, the Landcruiser, modifications to suspension and over 9 years ago- around $260,000. I think your $200,000 for the package is understating the costs
And for most people you can add the cost of where to store the bloody thing! Some people I know bought a motorhome, then decided to build a new carport for their updated fleet. ...Except someone screwed up and the new one encroached on council land, so they then had to negotiate purchase of that too. 🤣
Hi John, had a Ranger towing a 24ft caravan pass my on the Hume Highway, l was sitting at 100kls in my Dmax, then a steep hill, and the 2.2 kw Ranger stated to slow to 80klms so l passed maintaining my speed l was also towing a van, it's 18ft, once l was over the crest the next thing the Ranger flue pass and started to sway quit alot, credit to the driver he got it back under control, we both ended up at the same Caravan Park and l saw that he had twisted his tow ball to 5 degree from centre and was having trouble un hooking the van, this is happening to often and new towing laws are required, cheers,
@@TonyRule However, laws do allow tickets/citations/summonses to be issued after jobbos like that cause a crash because they were unqualified to operate the vehicle/trailer combination in the first place. Anyone driving a tow and trailer over a certain weight class should have to have a special license or permit to do so, including passing a written test.
My brother had one, I refused to own one. We went on holidays, I got there in an hour and a half and he got there in a couple of days. We compared the cost of air tickets and hotels to the cost of the caravan. No surprise, it was cheaper to fly, rent a car and stay in a hotel, plus Tiffany wasn't going to live in the caravan under any circumstances so there's that.
A while back in the American trucking industry, they did try, a limited test, putting what look like shortened tail cones on the back of dry vans. It did reduce turbulence and thus drag. The problem was, it interfered with loading and unloading and very often they were damaged and discarded. So the whole idea was discarded
Yep, I'm all for the big tube right through the middle of a highly inconvenient convenience. It took me back to the early 70's as a long distant truckie, struggling up Pretty Sally Hill on the Hume, in a busted arse butterbox ACCO and spread axle trailer....and then to being overtaken by some mug lair with a load of poly pipe onboard. I think I used to have dreams about carting poly pipe and listening to the wind whistling through them as I flew up Pretty Sally Hill. I never got to cart that sort of freight, so I haven't got a clue whether it whistled or not. Sleep deprivation does odd things to you, so it was all probably just a pipe dream anyway!
Laurie has achieved something trully remarkable. The design may not only direct air behind the box, but may also have the added advantage of seperating the lid of the van from the rear wall allowing the interior of the van to be watter cooled in the next QLD downpour.
John, I don't know about Australia, but in the US there are many places to go were there are no fancy hotels near by. And even if there were my diet of necessity requires home cooked meals. This leaves taking my home on wheels or not going at all. At my age (pre baby boomer) I no longer feel like roughing it in a tent. I like hot showers and a real bed to sleep in. And if you go on long vacations, say two months, then the savings start adding up. For instance the current price on a motel in a town I was expecting to stay a month at was $5,100, not including meals. When I was towing a camping trailer I did it behind a 3/4 ton Dodge Turbo Diesel 4 x 4. While I would not go the legal speed limit of 75 MPH on the freeways, I could. And, yes, fuel economy suffered.
Some trucks in the US do have a treatment on the back. It doesn't stick out beyond the outline of the trailer. Basically it tapers the dimension of the trailer down by about a foot on each side and the top. It seems that someone found it useful after all the other stuff was done.
Sir John, I fired up my CAD system, designed Earth's first warp-capable starship, and I'm building it in my backyard. Everybody sing! "It's been a long road, getting from there to here..." :) And #respect to the late Mad Mike Hughes, who built his own rocket and launched it, but died when it malfunctioned, jettisoning his parachute just after liftoff, and things went even worse from there. :(
I, too have begun a long-term and probably money-draining quest to build a caravan. Even worse - I drew it on the free Sketchup, and haven't done a day's study of engineering. Madness. C'est la vie. If I don't crash and burn the build, I think I will ask JC to review it, lol! Otherwise, I'll invite him to come and light the bonfire.
@@aussieideasman8498 "On this site, a money-draining caravan will be built. A caravan that will enable him to go nowhere, because the frame will collapse. Imagine it, his frame lying broken in the shop, the Chitroux balanced precariously. And he can't explore anywhere, or seek out new life, or new civilizations. This caravan will let him go no place, like no man has done before" (Parody of Zefram Cochrane's dedication of the Warp Five complex, which will happen soon in your timeline, but already happened in mine. :) ). ruclips.net/video/XHp0ZQruCkU/видео.html
@@markh.6687 In life, people try with some failing and others succeeding. When I get an idea, I have only two choices; forget it or try, and forgetting is instant failure. Trying involves risk, but has adventure, fulfillment and other rewards, either way. If I just wanted a caravan, I would simply buy one; it's far easier, cheaper and quicker, but I want to build an idea that is superior to what is available. It's not so much the van, but the idea. Besides, practically anyone can hand over a cheque (or direct debit these days).
@@aussieideasman8498 I am all for your attempts. I just couldn't resist the parody idea, after thinking how bad it could possibly go, especially after my other space-related reference. As Theodore Roosevelt wrote "...The credit belongs to the man in the arena...."
4:56 Please don't say _Super-Dooper-Pooper_ when my mouth is full of coffee! Got *that* close to spray paint my laptop a new color! I had to laugh through my ear drums!
Poor Laurie. Can't blaming for attempting to think outside the box. My cousin has just spent a heap on his first caravan, needless to say i sent him a tsunami of your caravaning videos. Cheers fat man you gave me a ton of ammo hahaha
JOHN BOY you have really out stretched yourself WELL DONE. Most Caravanners'[Grey Nomad's] these day's drive @90 to 100kph just because they can, and then wonder why they get into trouble. Towing Caravan's and trailer's the speed should be no faster than 85kph MAX, 80kph or less is the better speed as one has a chance to recover when the Caravan/Trailer starts to wag the tow vehicle.Especially in area's of severe cross wind's like on the National Highway between Redhill and Port Pirie SA.
If I ever build my van (and it works), I will be sure my tow vehicle can be set to not go over 80 kph. It makes perfect sense to use such a feature, and not rely on the foot. I am not going to travel to get there fast, and my motorbike is more the tool for that.
The rate of fuel consumption/drag saving by dropping from 100 to 80 is about 49%. Power needed is proportional to speed cubed (drag x speed). Drag is proportional to speed squared. => 80^3 ÷ 100^3 = 51.2% (Ingnoring rolling drag which is fairly insignificant at 80 to 100). Total fuel used is about 64% (the 30% John stated) Thanks to Thomas A for correction
Would the ultimate energy used come back to squared when you factor in the longer drive though? 50% of the power, for 125% of the time, ≈62% energy used @ 100? *I can’t remember the number John quoted, and I’m not familiar with your energy is proportional to cubed claim I’m just a particularly excitable electrician
@@thomasa5619 my calculation was based on steady speed of 100 vs 80. Drag FORCE = 1/2 × air density x velocity/speed^2 x Drag Coefficient Cd x Frontal Area. Power = Force x velocity So power = constant x velocity^3 Assuming air density, speed, Drag Coefficient and size don't change. Opening a window changes Drag Coefficient. See my other comments re my final year project for BE Mechanical was on exactly this
@@thomasa5619 fuel consumption is proportional to energy required. Not on power available. Same as electric motor. Might be 2.4 kW (10A) rated, but will only draw amps/power needed to do whatever work is required (up to its maximum) A grinder free spinning draws less amps/power than one grinding hard out on steel.
@@deanomarino31 I’m not good at writing these things so I’ll try to break it down with a simple example instead I can use 1 unit of fuel for an hour Or 0.5 units of fuel per hour, for 1.25 hours (inverse of 0.8, so it’s the same as 80 vs 100km/h) And then I’ve actually used 0.63 units of fuel Yes the power needed is a cube as speed increases, but when you get to the next servo, the fuel actually used, is only squared. (Assuming all else is equal)
@@thomasa5619 ahh yes. I was referring to RATE of fuel used. You are correct. Total fuel used = Original.total.fuel.at.100 x(80/100)^3 [reduction in rate of fuel use/power needed due to slower speed] ×100/80 [longer time taken to travel same distance at lower fuel usage rate]. I have edited my original comment accordingly. Thanks for spotting my error.
Those long haul trucks will be 2.5 m wide and 4.3 m tall, there will be no room for any spoil up whether it made a difference or not, because they are running at maximum size to fit in maximum cargo area.
The airfoil type idea is in use but not as a foil or spoiler. It's implemented as an extension of the trailer mounted at roughly a 25 to 30° acute angle from the sides and top of the trailer. The flaps exploit laminar flow of air, or it's tendency to stick to a surface. Reducing drag by using fluid dynamics instead of forcing the air, creating even more drag.
We towed a large trailer ( x caravan chassis ) with a Mercedies Sprinter van and the fuel use went from 9 l per 100 km to 10 l per 100 km. I have a converted bus 12.5 meters big enough to have the toilet away from the kitchen and it uses 18 - 20 liters per 100 km better than my neighbors 8 meter caravan that cost him 4 x as much and he is stuck driving a landcruser 95 % of the time. I have a 10 year old Nissan Leaf charged off solar power that I bought 3 months ago for $10,000.
I remember the old Holden Jackaroos had a spoiler like this integrated into the tailgate, although it worked more as an air curtain to keep dust of the back window than for any aerodynamic benefit.
@@jfv65 although their design wasn't bad, the roofline tapered down while the spoiler thing stayed at the same height, so you had a wide air duct along the back.
I’ve been a long time watcher John. Please don’t judge but I bought a camper van recently. I bought an older jayco flamingo. My main points of concern were, people not able to shit 4feet from the dining table and a lower roofline so my shitty old hilux is able to drag it easier. Love the videos John. 👌
Didn’t “team America” have some special 3m stuff on the hull of the boat to reduce drag? Maybe Laurie needs some of that!. Footnote they still lost the race🥸
My dad has a Avan Jack HT kerb weight of 1650kg loaded weight of around 1900kg with all the crap. He tows it with a 2017 VW Touareg V6 Tdi 180kw. Car averages 12L/100km he generally tows it at about 90ish KM/H him and Mum went all over Australia with the Combo and love it. I've used the Van for long stays 2 -3 months at a time, when I've had to travel for work. The Van tows well enough for a what it and Dirty Towrag can't be faulted as a tow vehicle plenty of power stable with the van and plenty of brakes. As for living in it, it's alright getting used to showering in it is the hardest thing. As for shitter it's never been used.
I was thinking about getting a caravan and 4x4 after 5 years slumming it in a small Toyota HiAce full time. After watching this, I think I’ll stick to upgrading to a bus instead.
The sketched "scoop" will reduce drag if placed on the front corners of the trailer/box. But must be at a specific curvature/ distance and location from the corner. If top and 2 sides have optimal "wings" the drag reduction is about 10% They reduce drag by acting as turning vane and keeping the air attached to the skin (removes turbulent and low pressure area just behind corner) AND also develops some life on the wing too. Again wind tunnel tested as part of my project. About 3% drop in drag from removing turbulent zone and 7% from lift. The wing on top front corner results in small lift on front of body. The two side wings mostly cancel but not completely when wind is at a yaw angle. My project was based on the shape of a Mitsi L300 Van from mid 80s. Effect of being a trailer was not tested, and expected to be similar but less reduction due to upset flow from the towing vehicle. Note. A 10% drag reduction can also be attained by dropping from 100 ks to 96 ks!!
This theory shit is all very well with a flat surface but the modern day poop mo-beel has a plethora of solar panels, fold down TV aerials, extractor fan bubbles (for the poop odour de colonge), air conditioners and skylights.
@@rond6783 exactly. My project was for vans or similar. So not really applicable to the "dirty surfaces" of a caravan. I have fitted them to my covered trailer that transports motorcycles or ATV. That trailer has flat surfaces, so the wings do help. They would help truck trailers too, except they vehicle would be over dimension and thus illegal 🤔
OK, I’m no expect, but I do know the reason formula 1 race cars, well race cars and sports cars in general, put spoilers on the rear of the cars is to increase downdraft to keep the rear of the vehicle tight to road so it doesn’t lift off when driving at nearly 200mph. Having seen fins on vans they do serve one purpose, other than looking stupid or making your van easier to find in the parking lot, they apply down draft to the rear windows to keep dust, rain and snow off the rear windows when driving. They sort of worked, they also created more drag, but no one ever reported improved mileage. Turns out putting a window wiper on the rear window is more effective and cheaper, at least when it comes to keeping the rear window clean. Semi trucks, in America anyway, have aero shaped cabs resembling giant wedges. Even older box shaped cabs have wind deflectors on the top at steep angles that are level with the trailer roofs all to give a more aerodynamic shape and lower drag. They are now enclosing the wheel wells, adding ground effect skirts to the underside of the trailers and an odd looking cone to the rear of the trailer, looks something like the flaps of a cardboard box that are partially closed, this too is to reduce drag and turbulence. According to trucker friends this does reduce fuel consumption so it must have effect on drag. But a fin on top of the trailer… 😂😂 That’s just redneck stupidity. Adding down draft to the back trailer is stupid, possibly a little dangerous, but it may keep the rear of the trailer a little cleaner.
It takes a special kind of someone to spend $100K on a caravan and then fit a home job wing on the back that your insurer will almost certainly use an excuse to void any claim in the case of an accident.
It's possible to design aerodynamic caravans that are really lightweight. Here in Europe lightweight caravans are becoming popular, especially with EV owners. Look up the Tab 400L from Knaus in Germany for example - "teardrop" shape, max laden 1.2 metric tons. It's a great little van that can easily be towed with most cars without annoying other road users. Surely more fun and relaxing to tow than a 3 ton monster van!
A concertina type sleeve between the towing vehicle and the trailer as on bendy buses perhaps might help the aerodynamics? I have seen articulated trucks with panels between the cab and trailer which slide out of the way when turns are required.
Hi John setting off around Australia in the next 12 months we haven't bought a caravan yet until I here back from you .I want to carry a 400 to 500cc motorcycle on the back of the van .I can buy the rack from the mx store but I want to know what mods would I have to do for caravan ,should it be a duel axle or can I use a single axle caravan that would suit my task thankyou for your input this will point me in the right direction regards Tony
Australian RV cooker/sleeper/pooper box owner: can I improve aerodynamics by adding a rear air deflector? John: No you can’t. Just park it and burn it to the ground.
Here is a question for your aerodynamic knowledge John. Backwards facing snorkels, they seem to be all the rage these days. If you are driving in a cloud of dust are you going to get more dust through the rear facing snorkel or the forward facing snorkel?
The idea that snorkels reduce dust intake is a marketing line promoted by companies that sell and install snorkels. There might be some small effect in certain circumstances, but generally there is not enough difference in dust intake between radiator height and snorkel height to make an appreciable difference. The only place where a snorkel makes a big difference is when in water deep enough that you wish you weren’t there. Dust ingestion characteristics are spin designed to separate you from your money.
Good thing you Dont get Caravans cheap. Otherwise the country we know as Strayla would be littered with the Aluminum pressed rolling lavatories. Love the work JC. P.s taking my first road train under permit from Vic to the Palace Chook border. Wish me luck towing two 40 foot trailer's using 17 litre diesel.
Oh come on John. who among up has not had the dream car designed in our head with enormous scoops on the doors and roof that funnel air to the rear in the name of going faster... and then had our 7th birthday. Let he who is without a freaking great air scoop on their kids dream go fastmobile cast the first rivet.
Some put vortex generators on them. A quick trip to the NASA hypersonic wind tunnel is in order. I am thinking retracting side flaps which tunnel air to the back and create a more streamlined exit to reduce turbulence. Or just buy more gas for the tow. May need some tail planes to laminarize the flow and prevent other vehicles from being blown off the road. Or not.
John, Im starting to feel like maybe you dont like caravaning! Youve gotta come at this with your engineering brain y'know, the shitter being so close to the dining table is just process efficiency. Gives you more time to...uhh...do something with those six beds?
John i think this guy was having you on and you jumped straight in .But a excellent laugh no one could be that stupid to think a spoiler would make a different on a big Ass caravan . keep up the great work enjoy all your videos..
LOL people towing a huge brick behind their 4x4 are worried about drag and aerodynamics. The brick we used to tow hardly even had any angle at all on the front end and the 4x4 had no turbo. 70-80kph into the wind on the flat was about normal.
I can fit my surf board, spare bed mattress and a tent in my 2003 BMW x5. It gets 9 liters per 100km on the highway. It's quite cosy, but we can afford it.
Think this spoiler shown would generate lift and increase drag. If it does it will apply more weight on the tow bar. The shitter next to kitchen always a great look. I think I would rather have the 5 star resort.
By including hydraulics, an industrial drilling auger and small tent you could reassign 1 square meter of space within the caravan for living space and be able to make a long drop anywhere. Nothing better than smashing a hole through the bitumen in the middle of nowhere and carefully burying your organic waste in your own private toilet. Up here for tinkin', down there for dancin'.
Great one again Johnno as someone who really hates the thought of even caravanning my question is if people want to “ruff it” why aren’t these Highway menaces just investing in great camping gear or even better a good hotel room seeing how said menaces obviously have a lot of money for these overpriced dummy and pooh storage facilities and the costs for running and keeping? Thoughts?
Depends on if you have a death wish or not. If you do anything, read your owner's manual for the towing vehicle to find out if you should INCREASE your tire pressure due to the load you're towing. Lowering your tire pressure may result in traction and stability issues as the tire deforms under load.
I think the wing proposed by your reader would create lift at the rear of the caravan, not downforce, which would obviously be bad. I reached this conclusion by studying the wing shape of our orphan baby black-headed flying fox, which has brilliant wings. An adult flying fox was recorded having flown from Brisbane to Melbourne in 10 days, which was amazing. Our son, who is studying engineering, recently had to make a balloon-powered helicopter, which required lots of head-scratching about aerodynamics and lift. I don't pretend to understand it very well. Basically, I suspect the shape of your reader's caravan would create a vacuum at the rear and suck in the dust. A wing at the top would do nothing to stop the dust collecting there, I think. Am I right? Mike the beard-scratching Defender driver.
If your reader wants to keep the dust off the rear of his caravan, maybe he should fit tubes running from the front to the back, exiting about halfway up the rear of the van, to send extra air in to reduce the vacuum at the rear of the van. There is a reason why Range Rovers have side vents in the engine bay just ahead of the doors, to let hot air out of the engine bay and create a greater vacuum which sucks in air through the radiator. Your reader wants to do the opposite and reduce the vacuum at the rear of his van by adding more air. Front to rear tubes could work. Alternatively, he could stop trying to fix a problem which doesn't matter, and go fishing.
As a long time advocate of the aluminium shitwa that many of us call a caravan (admittedly I prefer the shitwa piece in the back, away from the kitchen) I do agree with you about some peoples unreal expectations regarding what they need, want or desire in said aluminium shitwa on wheels and what can be reasonably transported along Australian roads by the currently available vehicles capable of and suitable to the task of towing, well anything larger than a wheelie bin. Maybe a change to the road licence system requiring passenger vehicle drivers to obtain a licence upgrade should they desire to increase their rolling mass from four wheels and 2 tonnes to anything greater like six wheels and 4 tonnes in a similar manner that the trucking industry differentiates between drivers of commercial light trucks and road trains. Needless to say that my idea will probably go down like a cup of cold sick with some of the aluminium shitwa on wheels brigade but many of us do actually take driving and safety seriously. Just my stupid thoughts on the subject, dude.
Lo and behold, after watching your spoiler video I came across a Landcruiser flatbed Ute with a large box on the tray and the exact same rear roof spoiler as in your video as well as an air deflector on the front of the box. What are the chances?
Heres an idea. Put the crapper out back on its own trailer and fair it into the main trailer to cut turbulence and please John. I've sent in the patent so if you want it, pay me.
Funny thing is that they make this spoiler of sorts. But not for this application. Products like these are marketed for school buses that operate in snowy areas to keep the rear windows clear of snow.
The advice I got about caravans was......the two best days in a caravaner's life are....The day they tow it home, and the day the next owner does the same.
My caravan is my home, but at least my shitoir is in it's own room. I saw a 'brilliant' plan of having the toilet on a slide out under the kitchen cafe seating, so if you are all sitting eating tea, you could just roll out the toilet and sit in the walkway to continue eating with the family at the same time. I wonder who thought that was a good idea.
Oh dear, the shitter in my boat is an arm length away from the galley. However it is useful for grabbing a frothy out of the fridge whilst on the throne.
I did exactly this type of wind tunnel study for my final year project for my Mechanical Engineering Degree.
The drag from the slightly REDUCED pressure behind the caravan/van/trailer/bluff body is called Form Drag. It is around 25% of total drag BUT the only efficient way to reduce it is to taper the rear shape. Like a wing or very very long VW beetle tail (3 to 4 times longer than its height!!)
The rear scoop like shown does reduce drag (about 5%) but the additional drag of the scoop (about 10%) results in nett increase of drag by about 5%.
I proved this by holding the scoop in position but not attached to the model in the wind tunnel. Then repeated with attached.
Also, shape, angle of attack AND distance from the body were very sensitive and had optimal positions w.r.t. shape and angle
thanks for your meaningful contribution
@@grimreaper6112 couldn't move it at all!!??
I towed a mini behind another mini (a framed). Low HP just means slower acceleration and lower top speed. Unless the van was the size/weight of a bus, then a Datsun could get it moving, albeit slowly
Informed science vs discombobulated uninformed arse pluck opinions. What would ScoMo do?
@@berniestever3881 the Prone Minister would claim franchise rights.
@@berniestever3881
Or any premier or o/seas politician or Fauc1 when it comes to C19 !!??
In the sixties I used an old clapped out caravan on a long route. It rocked. Yet it didn't leave her dad's back yard
🤣🤣🤣🤣🤣🤣🤣
Gold
She had a good chassis?
66
Viscountess von Tease?
Hi John. I’m an Auto Mechanic and just spent the last 15 minutes in stitches. Thanks for that. I love the way you bring facts and logic into your argument. By the way have you seen the UK Top Gear boys take the piss out of caravans and caravaners? I’m sure you have. Very funny and worth a look if you haven’t seen it. Thanks again for the laughs.
Funny this should come up. I was driving back from Wollongong down the Hume today and found myself in the vicinity of a massive f-off caravan being towed by a Ford Ranger in the Raptor config. I was doing the speed limit and this chap was overhauling me at speed on the downhill side and disappearing...until I caught him in the hills again, where he'd be chugging up and losing momentum at a rate of knots. As I overtook him for the fiftieth time before turning off at Yass, I remembered your earlier video on towing dynamics and the risks of towing at top (legal) speed, without any travel left in the pedal for emergency death wobble rectification. Good times.
Ha ha ha ha, 😬 the mind boggles,
Be cautious around situations like this; middle aged man relieving his youth while being hen pecked for short comings, historical or otherwise!.
@@tonyernst7090 Ha! HA! HA!
@@davexb6595 ha! Ha! He! He!
Average Guy: "How about a wing on my caravan to reduce drag?"
John: *Makes a 15 minute video taking the absolute piss*
Just like a comedian with a live audience...
There is always one loudmouth looking for and finding a putdown. LOL
Cruel, but fair, video John.
re: Setting it on fire. In QLD, any fire over 2 metres in any dimension requires a Permit, obtainable from your local Fire Warden (no charge). Nice one, John.
3:57 John, you hit the nail right on the head regarding the value of these expensive caravans (toilet towers). My neighbours across the road has one of these monstrosities which they use twice a year. As it's to large to store on their property, it goes to a storage shed in town until needed. When the owners get it out of storage, it's parked on the street blocking the better part of the road. They then spend 3 days cleaning it & stocking it with supplies, charging the batteries etc, before they make their "epic" trip (towing it with a 2021 Nissan Patrol) which is 2 hours away from home to make camp for a fortnight. During their fortnight away, they still call back home to mow the grass & do some cleaning. Then when they come back, they park it in the same spot, clean it inside & out and then store it away again. What is the point of owning a very large expensive towing toilet clogging up out highways?
They would be better off at a resort & they'd still save money!
See also: Boat ownership in many cases.
@@markh.6687 What's the "hotel/resort" equivalent in your argument against boat ownership?
@@ewicky I think you misunderstood; my point was buying expensive things to use them so rarely that the owner would be better off without. Boats are often the same thing; best day is when you buy your boat; 2nd best day is when you sell it. Knew someone that had a boat, he finally sold it and bought a much-more used motorcycle as a cheaper toy.
Now if you could only explain to caravanners why they should use slow vehicle turnouts instead of speeding up when they've been doing 20km/h below the speed limit on a tight bendy road with a trail of pissed-off cars behind them for the last 15km, that would be great.
A video tutorial on fitting tow-mirrors would help! 2/3 of all vans on the road can't see any more than the front of what is being towed.
It's not only caravaners who are in need of such edu-ma-cation.
@@rond6783 And not only in Shitsville. They're in plague proportions here in Sheepshagistan too.
@@TonyRule only the labour supporters though... the right, are more often than not considerate to others...
@@TonyRule not really different here in "Merica either.
old mate laurie is now driving to that massive rock in central Australia to live under, after that roasting😅😂😅
love your work, the honesty is breathtaking👍👍👍
I do actually believe you have taken the art of taking the piss to a completely new level respect John
I recently towed 2400 kg with my Prado locally. As it had little fuel in it, was empty and I was rolling solo at 60kg, I’m sure all was good weight wise. It was a short 3km trip to my local mechanic with a non running van on a tandem. That right there was experience enough to tell me there’s no way I’d put a 2t van on the back and tour Australia. I felt bad enough holding up people in suburban Melbourne and I’ve got a V6.
Not all people are as considerate as you unfortunately.
Here in the US I see trucks with spoilers like you showed in the video. I am inclined to think the reason trucks aren't more aerodynamic in the back is because they have to be able to back up to a dock door and get an air tight seal in some cases.
Yeah his truck idea isn't 100%
But here in Aus, there has been a few aero trailers made to success. But the loss of freight space to any aero designs canceled the financial benefits.
Good review John… loved your delivery as always. Hired a large caravan few years ago and towed with my Navara Ute, astonished of the amount of diesel used. Next one will be a small pop up just for the misses and me.
In my 3 decades of working in engineering, I've met many a Laurie. One conceived the idea to use the water flow in the downpipes when it was raining with a turbine to generate electricity to assist pumping that very same water up to the storage tank about 15m up the hillside.
Have you seen those marvelous downpipe water turbine generators on YT? They are often capable of producing up to 9 milli-Watts before becoming clogged with roof debris. Putting this abundant power source to use pumping huge volumes of water uphill should be a breeze.
@@philhealey449 Do the men wear skirts?
@@aussieideasman8498 Yes, but upside down.
@@philhealey449 Anything from skirted men (with bare feet or flip flops) is a scam. I was going to write 'thongs', but would confuse the Yanks.
@@aussieideasman8498 Great handle you've chosen there, from possibly one of the funniest movies made.
"You... are an ideas man, Steve."
One of your best bloke. Pissed myself laughing all the through it. Keep up the good work.
John, please tell me. I need to know how you can do a report like that without breaking down with laughter. #respect
Do you think there might be an ‘outtakes’ video, where he keeps falling off his stool laughing his arse off while producing this fine piece of work?
@@teefortony We need a blooper-reel edition, *stat*
It always amazes me how people think their $100 mod will make a vehicle much better and that none of the engineers working at the company that made the vehicle had thought about such an "ingenious" solution.
aftermarket miracles dreampt up to con the gullible
I know someone who bought the outback caravan, the Landcruiser, modifications to suspension and over 9 years ago- around $260,000. I think your $200,000 for the package is understating the costs
Faaaaaar out!!!!! What's the friggin point?????
@@Spacegoat92 need to upgrade suspension to tow caravan. You can spend as much as you want on your new caravan. This was not for me
And for most people you can add the cost of where to store the bloody thing! Some people I know bought a motorhome, then decided to build a new carport for their updated fleet. ...Except someone screwed up and the new one encroached on council land, so they then had to negotiate purchase of that too. 🤣
Hi John, had a Ranger towing a 24ft caravan pass my on the Hume Highway, l was sitting at 100kls in my Dmax, then a steep hill, and the 2.2 kw Ranger stated to slow to 80klms so l passed maintaining my speed l was also towing a van, it's 18ft, once l was over the crest the next thing the Ranger flue pass and started to sway quit alot, credit to the driver he got it back under control, we both ended up at the same Caravan Park and l saw that he had twisted his tow ball to 5 degree from centre and was having trouble un hooking the van, this is happening to often and new towing laws are required, cheers,
Laws don't fix stupid.
@@TonyRule However, laws do allow tickets/citations/summonses to be issued after jobbos like that cause a crash because they were unqualified to operate the vehicle/trailer combination in the first place. Anyone driving a tow and trailer over a certain weight class should have to have a special license or permit to do so, including passing a written test.
My brother had one, I refused to own one. We went on holidays, I got there in an hour and a half and he got there in a couple of days. We compared the cost of air tickets and hotels to the cost of the caravan. No surprise, it was cheaper to fly, rent a car and stay in a hotel, plus Tiffany wasn't going to live in the caravan under any circumstances so there's that.
A while back in the American trucking industry, they did try, a limited test, putting what look like shortened tail cones on the back of dry vans. It did reduce turbulence and thus drag. The problem was, it interfered with loading and unloading and very often they were damaged and discarded. So the whole idea was discarded
Yep, I'm all for the big tube right through the middle of a highly inconvenient convenience. It took me back to the early 70's as a long distant truckie, struggling up Pretty Sally Hill on the Hume, in a busted arse butterbox ACCO and spread axle trailer....and then to being overtaken by some mug lair with a load of poly pipe onboard.
I think I used to have dreams about carting poly pipe and listening to the wind whistling through them as I flew up Pretty Sally Hill. I never got to cart that sort of freight, so I haven't got a clue whether it whistled or not. Sleep deprivation does odd things to you, so it was all probably just a pipe dream anyway!
Good one, Madge! We saw the jokes you made; we'll allow them. :)
🤣🤣🤣🤣🤣🤣🤣
JC.....you should go into stand up comedy....I had tears within the first minute !!
👏👏👏👏👏🤣🤣🤣🤣
John Cadogan - Don;t shit where you eat. Words to live by:-)
shit where you eat. Words to die by (or at least suffer).
Spending 200k and camping in rest areas to avoid paying camp fees
Winning right there
Much like paying for a Tesla to save on the fuel difference.
Possibly the funniest report ever. Had me in stiches. .. and i don't mind the occasional camping or caravan trip with the family.
Is John secretly a caravaner? Me thinks he doth protest too much.
John is suffering from caravan envy. Remember he bagged twin cabs (triton utes) for years until he bought one.
Laurie has achieved something trully remarkable. The design may not only direct air behind the box, but may also have the added advantage of seperating the lid of the van from the rear wall allowing the interior of the van to be watter cooled in the next QLD downpour.
John, I don't know about Australia, but in the US there are many places to go were there are no fancy hotels near by. And even if there were my diet of necessity requires home cooked meals. This leaves taking my home on wheels or not going at all. At my age (pre baby boomer) I no longer feel like roughing it in a tent. I like hot showers and a real bed to sleep in. And if you go on long vacations, say two months, then the savings start adding up. For instance the current price on a motel in a town I was expecting to stay a month at was $5,100, not including meals.
When I was towing a camping trailer I did it behind a 3/4 ton Dodge Turbo Diesel 4 x 4. While I would not go the legal speed limit of 75 MPH on the freeways, I could. And, yes, fuel economy suffered.
you just can't be real, john, I didn't lough like that in months! love it
Some trucks in the US do have a treatment on the back. It doesn't stick out beyond the outline of the trailer. Basically it tapers the dimension of the trailer down by about a foot on each side and the top. It seems that someone found it useful after all the other stuff was done.
If it's the US; reason to investigate further.
I love the way you explain by example in this video you made my day regards
Sir John, I fired up my CAD system, designed Earth's first warp-capable starship, and I'm building it in my backyard. Everybody sing! "It's been a long road, getting from there to here..." :) And #respect to the late Mad Mike Hughes, who built his own rocket and launched it, but died when it malfunctioned, jettisoning his parachute just after liftoff, and things went even worse from there. :(
I, too have begun a long-term and probably money-draining quest to build a caravan. Even worse - I drew it on the free Sketchup, and haven't done a day's study of engineering. Madness. C'est la vie. If I don't crash and burn the build, I think I will ask JC to review it, lol! Otherwise, I'll invite him to come and light the bonfire.
@@aussieideasman8498 "On this site, a money-draining caravan will be built. A caravan that will enable him to go nowhere, because the frame will collapse. Imagine it, his frame lying broken in the shop, the Chitroux balanced precariously. And he can't explore anywhere, or seek out new life, or new civilizations. This caravan will let him go no place, like no man has done before"
(Parody of Zefram Cochrane's dedication of the Warp Five complex, which will happen soon in your timeline, but already happened in mine. :) ).
ruclips.net/video/XHp0ZQruCkU/видео.html
@@markh.6687 In life, people try with some failing and others succeeding. When I get an idea, I have only two choices; forget it or try, and forgetting is instant failure. Trying involves risk, but has adventure, fulfillment and other rewards, either way. If I just wanted a caravan, I would simply buy one; it's far easier, cheaper and quicker, but I want to build an idea that is superior to what is available. It's not so much the van, but the idea. Besides, practically anyone can hand over a cheque (or direct debit these days).
@@aussieideasman8498 I am all for your attempts. I just couldn't resist the parody idea, after thinking how bad it could possibly go, especially after my other space-related reference. As Theodore Roosevelt wrote "...The credit belongs to the man in the arena...."
@@markh.6687 I am all for your comments.
4:56 Please don't say _Super-Dooper-Pooper_ when my mouth is full of coffee! Got *that* close to spray paint my laptop a new color! I had to laugh through my ear drums!
Laugh through your ear drums? That's a skill seldom seen in this day and age.
Poor Laurie. Can't blaming for attempting to think outside the box. My cousin has just spent a heap on his first caravan, needless to say i sent him a tsunami of your caravaning videos. Cheers fat man you gave me a ton of ammo hahaha
JOHN BOY you have really out stretched yourself WELL DONE. Most Caravanners'[Grey Nomad's] these day's drive @90 to 100kph just because they can, and then wonder why they get into trouble.
Towing Caravan's and trailer's the speed should be no faster than 85kph MAX, 80kph or less is the better speed as one has a chance to recover when the Caravan/Trailer starts to wag the tow vehicle.Especially in area's of severe cross wind's like on the National Highway between Redhill and Port Pirie SA.
If I ever build my van (and it works), I will be sure my tow vehicle can be set to not go over 80 kph. It makes perfect sense to use such a feature, and not rely on the foot. I am not going to travel to get there fast, and my motorbike is more the tool for that.
Most entertaining aerodynamics lesson. Almost worth a trip to dingo piss creek,without a caravan.
The rate of fuel consumption/drag saving by dropping from 100 to 80 is about 49%. Power needed is proportional to speed cubed (drag x speed). Drag is proportional to speed squared. => 80^3 ÷ 100^3 = 51.2% (Ingnoring rolling drag which is fairly insignificant at 80 to 100).
Total fuel used is about 64% (the 30% John stated)
Thanks to Thomas A for correction
Would the ultimate energy used come back to squared when you factor in the longer drive though? 50% of the power, for 125% of the time, ≈62% energy used @ 100?
*I can’t remember the number John quoted, and I’m not familiar with your energy is proportional to cubed claim
I’m just a particularly excitable electrician
@@thomasa5619 my calculation was based on steady speed of 100 vs 80.
Drag FORCE = 1/2 × air density x velocity/speed^2 x Drag Coefficient Cd x Frontal Area.
Power = Force x velocity
So power = constant x velocity^3
Assuming air density, speed, Drag Coefficient and size don't change.
Opening a window changes Drag Coefficient.
See my other comments re my final year project for BE Mechanical was on exactly this
@@thomasa5619 fuel consumption is proportional to energy required. Not on power available. Same as electric motor. Might be 2.4 kW (10A) rated, but will only draw amps/power needed to do whatever work is required (up to its maximum) A grinder free spinning draws less amps/power than one grinding hard out on steel.
@@deanomarino31 I’m not good at writing these things so I’ll try to break it down with a simple example instead
I can use 1 unit of fuel for an hour
Or 0.5 units of fuel per hour, for 1.25 hours (inverse of 0.8, so it’s the same as 80 vs 100km/h)
And then I’ve actually used 0.63 units of fuel
Yes the power needed is a cube as speed increases, but when you get to the next servo, the fuel actually used, is only squared. (Assuming all else is equal)
@@thomasa5619 ahh yes. I was referring to RATE of fuel used. You are correct. Total fuel used = Original.total.fuel.at.100 x(80/100)^3 [reduction in rate of fuel use/power needed due to slower speed] ×100/80 [longer time taken to travel same distance at lower fuel usage rate].
I have edited my original comment accordingly. Thanks for spotting my error.
Those long haul trucks will be 2.5 m wide and 4.3 m tall, there will be no room for any spoil up whether it made a difference or not, because they are running at maximum size to fit in maximum cargo area.
*spoiler up there.
The airfoil type idea is in use but not as a foil or spoiler. It's implemented as an extension of the trailer mounted at roughly a 25 to 30° acute angle from the sides and top of the trailer. The flaps exploit laminar flow of air, or it's tendency to stick to a surface. Reducing drag by using fluid dynamics instead of forcing the air, creating even more drag.
Never get tired of this.
We towed a large trailer ( x caravan chassis ) with a Mercedies Sprinter van and the fuel use went from 9 l per 100 km to 10 l per 100 km. I have a converted bus 12.5 meters big enough to have the toilet away from the kitchen and it uses 18 - 20 liters per 100 km better than my neighbors 8 meter caravan that cost him 4 x as much and he is stuck driving a landcruser 95 % of the time. I have a 10 year old Nissan Leaf charged off solar power that I bought 3 months ago for $10,000.
I remember the old Holden Jackaroos had a spoiler like this integrated into the tailgate, although it worked more as an air curtain to keep dust of the back window than for any aerodynamic benefit.
You trade off additional drag and mass for a clean rear window.
That is some sort of 'benefit' , isn't it?
@@jfv65 although their design wasn't bad, the roofline tapered down while the spoiler thing stayed at the same height, so you had a wide air duct along the back.
These first became popular in the 70's with the Ford and Holden station wagons and panel vans.
To cite the alleged moonlanding at the end was hilariois. 🤣🤣 Boom. Fxxx the spoiler 😂😂😂
I’ve been a long time watcher John. Please don’t judge but I bought a camper van recently.
I bought an older jayco flamingo. My main points of concern were, people not able to shit 4feet from the dining table and a lower roofline so my shitty old hilux is able to drag it easier.
Love the videos John. 👌
He just needs a couple of vinyl go faster stripes, bonus benefits if they are red, fixes speed and aerodynamics.
Didn’t “team America” have some special 3m stuff on the hull of the boat to reduce drag? Maybe Laurie needs some of that!. Footnote they still lost the race🥸
Just a fantastic dissatation from one caravan hater to another, loved it.
Mate, you take bagging to a whole new level!
My dad has a Avan Jack HT kerb weight of 1650kg loaded weight of around 1900kg with all the crap. He tows it with a 2017 VW Touareg V6 Tdi 180kw. Car averages 12L/100km he generally tows it at about 90ish KM/H him and Mum went all over Australia with the Combo and love it. I've used the Van for long stays 2 -3 months at a time, when I've had to travel for work. The Van tows well enough for a what it and Dirty Towrag can't be faulted as a tow vehicle plenty of power stable with the van and plenty of brakes. As for living in it, it's alright getting used to showering in it is the hardest thing. As for shitter it's never been used.
I was thinking about getting a caravan and 4x4 after 5 years slumming it in a small Toyota HiAce full time. After watching this, I think I’ll stick to upgrading to a bus instead.
It was about time you revisited your favourite piss-take John. You didn’t disappoint.
The sketched "scoop" will reduce drag if placed on the front corners of the trailer/box. But must be at a specific curvature/ distance and location from the corner.
If top and 2 sides have optimal "wings" the drag reduction is about 10%
They reduce drag by acting as turning vane and keeping the air attached to the skin (removes turbulent and low pressure area just behind corner)
AND also develops some life on the wing too. Again wind tunnel tested as part of my project. About 3% drop in drag from removing turbulent zone and 7% from lift. The wing on top front corner results in small lift on front of body. The two side wings mostly cancel but not completely when wind is at a yaw angle. My project was based on the shape of a Mitsi L300 Van from mid 80s.
Effect of being a trailer was not tested, and expected to be similar but less reduction due to upset flow from the towing vehicle.
Note. A 10% drag reduction can also be attained by dropping from 100 ks to 96 ks!!
This theory shit is all very well with a flat surface but the modern day poop
mo-beel has a plethora of solar panels, fold down TV aerials, extractor fan bubbles (for the poop odour de colonge), air conditioners and skylights.
@@rond6783 exactly. My project was for vans or similar. So not really applicable to the "dirty surfaces" of a caravan. I have fitted them to my covered trailer that transports motorcycles or ATV. That trailer has flat surfaces, so the wings do help.
They would help truck trailers too, except they vehicle would be over dimension and thus illegal 🤔
OK, I’m no expect, but I do know the reason formula 1 race cars, well race cars and sports cars in general, put spoilers on the rear of the cars is to increase downdraft to keep the rear of the vehicle tight to road so it doesn’t lift off when driving at nearly 200mph. Having seen fins on vans they do serve one purpose, other than looking stupid or making your van easier to find in the parking lot, they apply down draft to the rear windows to keep dust, rain and snow off the rear windows when driving. They sort of worked, they also created more drag, but no one ever reported improved mileage. Turns out putting a window wiper on the rear window is more effective and cheaper, at least when it comes to keeping the rear window clean. Semi trucks, in America anyway, have aero shaped cabs resembling giant wedges. Even older box shaped cabs have wind deflectors on the top at steep angles that are level with the trailer roofs all to give a more aerodynamic shape and lower drag. They are now enclosing the wheel wells, adding ground effect skirts to the underside of the trailers and an odd looking cone to the rear of the trailer, looks something like the flaps of a cardboard box that are partially closed, this too is to reduce drag and turbulence. According to trucker friends this does reduce fuel consumption so it must have effect on drag. But a fin on top of the trailer… 😂😂 That’s just redneck stupidity. Adding down draft to the back trailer is stupid, possibly a little dangerous, but it may keep the rear of the trailer a little cleaner.
Re direct the chuff gas from the pooper to the rear of the van. Will help to reduce the tailback as well. Bonus!!!
I wonder how hard ASPW laughed at the caravan in the thumbnail. I did...😀😀😁😂😃😃😂👍
Need some F1 inspired caravans.
A DRS rear spoiler on old mates van, activates only on freeways at speeds greater than 100kph
You sir are a mad man! 🤣😅
It takes a special kind of someone to spend $100K on a caravan and then fit a home job wing on the back that your insurer will almost certainly use an excuse to void any claim in the case of an accident.
Stupidity is why humanity can't have nice things.
Hang on a minute there John. The pooper can act as another seat for those times when you have people over for dinner.
I'm a pilot and flying instructor with a fairly good handle on aerodynamics, but I couldn't and wouldn't try to solve that problem
It's possible to design aerodynamic caravans that are really lightweight. Here in Europe lightweight caravans are becoming popular, especially with EV owners. Look up the Tab 400L from Knaus in Germany for example - "teardrop" shape, max laden 1.2 metric tons. It's a great little van that can easily be towed with most cars without annoying other road users. Surely more fun and relaxing to tow than a 3 ton monster van!
In the UK, people who tow these are limited to 80kph, seems that Sir John sets our laws from a far.
90km/h here in Sheepshagistan for IIRC over 15 years now, up from 80km/h (no, not Wales - the one in the south).
@@TonyRule Caravans get stopped a lot in the UK, they are the only things our shit police cars can catch.
I think 🤔 the 1960s Valiant safari station wagon had two side mounted ones supposedly to keep the rear window dust free
Yep they did. The XB Fairmont wagons had a top one for the same reason, keep the back window cleaner
This cracks me up! Thanks for the humour.
"Double belgian chocolate supreme of road-going cockroaches" I love these unique insults of John :D
So, what I'm hearing is - if I paint flames up the side of a panel van, it won't go faster?
I had that same thing on my old XF Falcon wagon. But that was just to keep the back window clean.
The Ioniq 5 does it, and it doesn't work. Wipers work.
100 grand - hold that - that's the cost of a granny flat
A concertina type sleeve between the towing vehicle and the trailer as on bendy buses perhaps might help the aerodynamics? I have seen articulated trucks with panels between the cab and trailer which slide out of the way when turns are required.
Hi John setting off around Australia in the next 12 months we haven't bought a caravan yet until I here back from you .I want to carry a 400 to 500cc motorcycle on the back of the van .I can buy the rack from the mx store but I want to know what mods would I have to do for caravan ,should it be a duel axle or can I use a single axle caravan that would suit my task thankyou for your input this will point me in the right direction regards Tony
Australian RV cooker/sleeper/pooper box owner: can I improve aerodynamics by adding a rear air deflector?
John: No you can’t. Just park it and burn it to the ground.
Here is a question for your aerodynamic knowledge John.
Backwards facing snorkels, they seem to be all the rage these days.
If you are driving in a cloud of dust are you going to get more dust through the rear facing snorkel or the forward facing snorkel?
good question. passive or active?
The idea that snorkels reduce dust intake is a marketing line promoted by companies that sell and install snorkels. There might be some small effect in certain circumstances, but generally there is not enough difference in dust intake between radiator height and snorkel height to make an appreciable difference. The only place where a snorkel makes a big difference is when in water deep enough that you wish you weren’t there. Dust ingestion characteristics are spin designed to separate you from your money.
Good thing you Dont get Caravans cheap.
Otherwise the country we know as Strayla would be littered with the Aluminum pressed rolling lavatories. Love the work JC.
P.s taking my first road train under permit from Vic to the Palace Chook border. Wish me luck towing two 40 foot trailer's using 17 litre diesel.
Oh come on John. who among up has not had the dream car designed in our head with enormous scoops on the doors and roof that funnel air to the rear in the name of going faster... and then had our 7th birthday.
Let he who is without a freaking great air scoop on their kids dream go fastmobile cast the first rivet.
7th Birthday?? I wanted it for my 56th!
@@markh.6687 But... you did understand that it was just a dream
@@phillipkidd762 Nope. AND I wanted hot women in the car with me! :)
Some put vortex generators on them. A quick trip to the NASA hypersonic wind tunnel is in order. I am thinking retracting side flaps which tunnel air to the back and create a more streamlined exit to reduce turbulence. Or just buy more gas for the tow. May need some tail planes to laminarize the flow and prevent other vehicles from being blown off the road. Or not.
John, Im starting to feel like maybe you dont like caravaning! Youve gotta come at this with your engineering brain y'know, the shitter being so close to the dining table is just process efficiency. Gives you more time to...uhh...do something with those six beds?
John i think this guy was having you on and you jumped straight in .But a excellent laugh no one could be that stupid to think a spoiler would make a different on a big Ass caravan . keep up the great work enjoy all your videos..
I think the only reason the rear of a tuck is flat is that it has a door any other shape would make loading a pain
It's a good point, I'm just too scared to try now, lol
Not if you use Laurie’s 32mm patented roof spoiler lol.
LOL people towing a huge brick behind their 4x4 are worried about drag and aerodynamics. The brick we used to tow hardly even had any angle at all on the front end and the 4x4 had no turbo. 70-80kph into the wind on the flat was about normal.
I can fit my surf board, spare bed mattress and a tent in my 2003 BMW x5. It gets 9 liters per 100km on the highway. It's quite cosy, but we can afford it.
Think this spoiler shown would generate lift and increase drag. If it does it will apply more weight on the tow bar. The shitter next to kitchen always a great look. I think I would rather have the 5 star resort.
Laurie misspelt the name of his "bran spanking new SEWAGE XU." 😂
So is it less stupid for one wants to opt out to get a camper van or mobile home, (with outside toilet of course)?
By including hydraulics, an industrial drilling auger and small tent you could reassign 1 square meter of space within the caravan for living space and be able to make a long drop anywhere. Nothing better than smashing a hole through the bitumen in the middle of nowhere and carefully burying your organic waste in your own private toilet. Up here for tinkin', down there for dancin'.
Great one again Johnno as someone who really hates the thought of even caravanning my question is if people want to “ruff it” why aren’t these Highway menaces just investing in great camping gear or even better a good hotel room seeing how said menaces obviously have a lot of money for these overpriced dummy and pooh storage facilities and the costs for running and keeping? Thoughts?
These highway menaces pay rego and taxes and have as much right to be on the road like everyone else.
Should i have lower tire pressure in the rain while towing?
Depends on if you have a death wish or not. If you do anything, read your owner's manual for the towing vehicle to find out if you should INCREASE your tire pressure due to the load you're towing. Lowering your tire pressure may result in traction and stability issues as the tire deforms under load.
Some of your best work John🤣🤣🤣
I think the wing proposed by your reader would create lift at the rear of the caravan, not downforce, which would obviously be bad.
I reached this conclusion by studying the wing shape of our orphan baby black-headed flying fox, which has brilliant wings. An adult flying fox was recorded having flown from Brisbane to Melbourne in 10 days, which was amazing.
Our son, who is studying engineering, recently had to make a balloon-powered helicopter, which required lots of head-scratching about aerodynamics and lift. I don't pretend to understand it very well.
Basically, I suspect the shape of your reader's caravan would create a vacuum at the rear and suck in the dust.
A wing at the top would do nothing to stop the dust collecting there, I think. Am I right?
Mike the beard-scratching Defender driver.
If your reader wants to keep the dust off the rear of his caravan, maybe he should fit tubes running from the front to the back, exiting about halfway up the rear of the van, to send extra air in to reduce the vacuum at the rear of the van.
There is a reason why Range Rovers have side vents in the engine bay just ahead of the doors, to let hot air out of the engine bay and create a greater vacuum which sucks in air through the radiator.
Your reader wants to do the opposite and reduce the vacuum at the rear of his van by adding more air. Front to rear tubes could work.
Alternatively, he could stop trying to fix a problem which doesn't matter, and go fishing.
Hi John, am wondering how many $200,000 relationship killers are purchased with borrowed money? lent against equity in a housing bubble economy?
Got a Falcon and stay in nice motels. The best way to travel. :)
You mean "Got a Falcon; the best way to travel, and stay in nice motels - a way to not travel. Motels don't move.
As a long time advocate of the aluminium shitwa that many of us call a caravan (admittedly I prefer the shitwa piece in the back, away from the kitchen) I do agree with you about some peoples unreal expectations regarding what they need, want or desire in said aluminium shitwa on wheels and what can be reasonably transported along Australian roads by the currently available vehicles capable of and suitable to the task of towing, well anything larger than a wheelie bin. Maybe a change to the road licence system requiring passenger vehicle drivers to obtain a licence upgrade should they desire to increase their rolling mass from four wheels and 2 tonnes to anything greater like six wheels and 4 tonnes in a similar manner that the trucking industry differentiates between drivers of commercial light trucks and road trains. Needless to say that my idea will probably go down like a cup of cold sick with some of the aluminium shitwa on wheels brigade but many of us do actually take driving and safety seriously. Just my stupid thoughts on the subject, dude.
The one and only Nissan tunnel race car was an aerodynamic success.
Lo and behold, after watching your spoiler video I came across a Landcruiser flatbed Ute with a large box on the tray and the exact same rear roof spoiler as in your video as well as an air deflector on the front of the box. What are the chances?
Heres an idea. Put the crapper out back on its own trailer and fair it into the main trailer to cut turbulence and please John. I've sent in the patent so if you want it, pay me.
Funny thing is that they make this spoiler of sorts. But not for this application. Products like these are marketed for school buses that operate in snowy areas to keep the rear windows clear of snow.
The advice I got about caravans was......the two best days in a caravaner's life are....The day they tow it home, and the day the next owner does the same.
Not in that order, of course.
John could you please do an update on covid 19 numbers
John, you had really good idea (about modifying caravan), why haven't anyone tried your idea? 😂😂😂
My caravan is my home, but at least my shitoir is in it's own room. I saw a 'brilliant' plan of having the toilet on a slide out under the kitchen cafe seating, so if you are all sitting eating tea, you could just roll out the toilet and sit in the walkway to continue eating with the family at the same time. I wonder who thought that was a good idea.
Oh dear, the shitter in my boat is an arm length away from the galley. However it is useful for grabbing a frothy out of the fridge whilst on the throne.