Using a vintage magazine for inspiration is a great idea, please keep producing more in this series. I think that you did Ernest proud and I wish the project all the best.
I was thinking the same thing. Now, how many of those that criticized the original video will actually submit a new design? Genius move by Jason on that part.
the number of people who didnt even understand the project wow. it was so clear he just wanted to have fun buildling a cool thing by recreating something from an image. meanwhile people: "why didnt you buy it", "put a motor on it", etc
I appreciate the video but people with all these complaints completely miss the point of these projects. If it were me I wouldn't make a video to address these complaints, they can go kick rocks 🤣. Keep up the great work ! 👍
Its crazy how many people didn't understand the purpose of the original video. did they skip the intro? fall asleep and wake up with the video playing? how do people misunderstand building something from a old magazine for fun and education without throwing modern technology on it? this is an awesome series.
That prop could be optimized a lot! Spin it at a fixed RPM and measure the power using an electric motor and volt and amp meters. Modify to get max RPM at min power, then repeat your experiments. I think that large flat area in the middle parallel to the shaft is just stirring the air, contributing drag and not thrust. FWIW, I think this is a pretty cool experiment, a blast from the past!
I think you did a GREAT job building it and explaining your rationale. More thought went into designing your project than into all the questions combined.
I'd love to see some real Computational Fluid Dynamics testing on that shape propeller, and then see how far that design could be pushed without changing the materials or the size, but only the shape.
FWIW, I do tend to agree with others here that the large area in the center that’s parallel to the axis of rotation is just making for more drag. It makes for a simple fab, and avoids strength issues at the root, but it’d be much better if you lopped off a lot of that “vertical” material. That aside, I imagine that the optimal design (size, pitch, etc) will depend a lot on the characteristics of the particular “motor” 😉 Some people might have their max power output at a higher rpm, others at lower one. I love your idea I’d having the viewers contribute designs! (!) Unfortunately, I: - Don’t have the skills - Don’t have a slip-roll - Am currently 100% busy setting up my first metal lathe (woohoo! 🎉)
We still have a competitive yearly self propelled craft into the sea here in England. It's awesome to watch. You covered basically everything in your original video. I'm worried about some of the other subscribers as you had to make this video😅😂ThankQ.TkEZ>UK
Also love that you do this QA for us fans were all builders for the most part so seeing other peoples ideas expands our own ideas plus I like anything that makes me think and learn
I love the Popular Mechanics builds. Too fun. Thanks for all the great content, Jason! Your diplomacy and patience, with the people who made rude or ignorant comments, is incredible. There were moments when it looked like you were grinding your teeth. :)
6:50: That is why airplane propellers blades are twisted up like they are and shaped like clover leaves --- in order to provide uniform airflow over all their cross sections in spite of those differences in air movement at the edges. For that is what you need for efficient propeller-driven flight. Even some large commercial fans are made with propeller-like kinds of fan blades.
I hate it when people dis old designs so many things we use are old designs that don’t need any improvement makes me sad for the future if you never failed you never truly tried
I really enjoy your videos and I'm excited to see you challenging your critics to put their money where their mouth is. I hope you just keep doing what you have been, you're a great creator.
I like your videos, but some of the things re-explained here are still incorrect. The pitch of a propeller is steeper at the root because the velocity of the propeller is lower at the centre. It is *not* because of torque limitations. The total diameter of the propeller is usually what is adjusted to limit the torque requirements. A propeller is a wing, and wings only work properly at a very specific 'angle of attack'. The angle of attack is the relative angle between the blade chord and the oncoming air. The angle of attack needs to be constant, from root to tip. Because the tip moves faster, it therefore needs to be shallower than the root. A propeller without twist will only have a narrow 'ring' producing thrust. The root will be too shallow (producing drag) and the tip will be too steep (stalled, making the air turbulent but not accelerating it rearwards).
Yep! Exactly. I actually just posted this exact explanation and then read yours, so I had to edit and cut it all out. I would be willing to bet the performance of this bike would be increased significantly by a better prop design, as the static lift of a properly shaped wing is considerably more than the dynamic lift. It would have a comical, exaggerated shape, but I think it would work.
Couple thoughts: 1. Use the bike's original gearing to allow you to start the propeller and then shift to get it going faster. 2. There is a lot of surface area that is parallel to the rotation axis. Completely parallel means wasted effort. You could probably improve performance just by cutting some of that area away, as much as possible without making the rest of it floppy.
Not trying to be pedantic, but torque is what you referring to throughout this video. The motor "power" and the human "power" never changes no matter how hard something becomes. The mechanical advantages do change. (torque multiplication) I love your metal working skills and artistry.
what u accomplished as a result of true to the book is 100% also what you accomplish vid after video is astounding i thought you would not top your last vid then bam and them bam never a dull moment with yoy Jason i would love to have u as a boss LOL respects
I was not asking you to put a motor so you wouldn't have to pedal it, I was really surprised it worked. I meant "put an 80cc two-stroke motor to make it a moped to see if it actually worked as well as the pedal bike with the same motor", like 25-35 mph. I suspected from what you said that it might do quite well, and be a credit to Ernest's propeller, which he actually designed and made, instead of just the bicycle, that he bought at Kmart or Sears, which I appreciated for its design sense and being a steel frame that can hold up all that equipment, flex, and take a weld. The weight and mass is the similar - experience repeated. You can mount the motor sideways (or up front on the top tube for better balance?) and attach a sprocket and chain to the prop shaft while maintaining the ability to pedal it. Anything which drives the wheels and not the propeller (like an electric hub motor) = stupid and pointless, unless you are trying to test if the airspeed of the moving bike moves the propeller? If you want speed, get some big motor, but I just wanted to see more testing. Weld two whistles to the ends to alert pedestrians, but it doesn't seem like there were any people there except your crew. My only question: Dear Ernest, What happens if you pedal backwards - brake, reverse, or nothing? - Cannot tell me a motor would not help with that test. And yeah, I did not think you could pedal it sufficient to actually see how good it is; because you said exactly that - there is no control variable, and maybe you get winded on the first ride and flop on the second, and the same with the pro (there are so many types, maybe a long distance or track rider would fare better)? I don't really believe that bicycles are at the level of technical refinement that you say, maybe I should add a variable pitch propeller to my bike? 16-20mph is a pretty good speed for a bike, and everyone is unfamiliar with this thing...
Please keep up these projects, you have the patience of Job answering these comments. (Any current deals on slightly used squares that might have some small dings 🙂)
nice, thanks, very inspiring! :-) lots of ideas for optimization - but here are maybe some slightly different considerations: - more safety! rider protective gear, attach brake to propeller shaft, ... at least paint the propeller's tips bright red for maximum awareness - did you balance out the propeller? if it requires a lot of filing, you can add varnish to the other blade - maybe a good way to create a propeller would be to cut open a tube along it's length (actually two half-length cuts, one from each side) and gradually unroll it, starting from the center? - maybe try some time trial handlebar for more weight towards the front? - maybe use bike drive chain & front derailleur as 2-speed gear? (then belt for direction) - toothed belt? ... .... very nice project :)
The only thing i wanted to see added to the first video was a track cyclist ride it. The guys from indoor track cycling with giant legs who only want to go fast but not necessarily for a long time. I know the first video had an actual cyclist but he is a road rider where endurance is the goal
Think you were right the first time. 'Variable pitch' is set at build but varies along the chord, 'Controllable pitch' is the one you can change in flight, or ride, as it were.
22:21: Yes, Fireball Tool. I fully understand that your propeller bike wasn't meant to be a real bicycle; it was only to test what a propeller can do on a bike. Concepts are nice for people like me who are curious even when those concepts are not practical to everyday life. I am glad you tried it. But now you still might want to keep that propeller bike around for people who want to try it out for themselves as a toy.
Have you considered a lightweight pedal assist on the crank, using a small battery to add and even out torque application between pedal strokes could help you greatly.
I really like your effort with making this cool bike! I have actually thought about making a propeller bicycle since many years. I understand your purpose was to try out a propeller like the one from the old magazine. But this propeller is horribly inefficient and pushes the most of the air towards the sides instead of backwards. I am very interested to know the result with an efficient and optimized propeller. You would go much faster!
@@patricj951 Lets place some bets! I think the old man was within 50% (30mph) of modern tech. Ultra light carbon bike with an optimized prop, still wont do better than 30mph or a 50% improvement...
@@patricj951 I do think it will be faster... I'm speculating on how much faster. I think Earnest was within 50% improvement. So if his 60s design did 20mph, I think using modern tech/materials, will only yield, at most, a 50% increase in top speed, so no more than 30mph.
I was thinking that more blades might help. Like adding a third blade, reduce the size of the blades overall to compensate for the additional surface area of the third blade. That's about all I can offer, I am not really at an engineer's level yet.
Your explanation of having to have the prop move "more air" near the hub, isn't exactly correct. On aircraft, the prop tip has a flatter pitch than the hub, because the radius is obviously longer, thus the tip is travelling more distance "around the hub" for each revolution and is thus traveling faster. This also means the tip is traveling "through the air" faster than the cross sections of the blade nearer the hub. The propeller blade behaves like a wing, and to be efficient the flow need to stay attached to the convex side as much as possible. Thus, to keep the flow attached and the prop cross section efficient, the pitch must be decreased as you get further away from the hub. The hub, due to obstructions and the fact it's not operating in "clean" air, is actually the least efficient portion of the propeller.
should have read before writing. yep, getting the propeller to effectively push air, and minimize the drag of the spin, (to require less torque generated by the biker) requires that the angle of attack be optimal on all segments.
1:24 Instead of putting gearbox in the pedal area, you could put one in the propeller shaft instead, it will not require manipulations with the frame. I wonder how more efficient it will be and will it be worth the effort
Maybe you could do some sort of collaboration with Furze for some of the mad ideas..Eg: Make it go really fast (make him ride it though and play some great punk music). I am sure between the two of you the viewers would end up with some great entertainment...
Good presentation. I would like to knitpick one area though. The twisted shape of the prop blades isn't so much to do with torque as it is laminar flow. Closer to the hub, the prop is moving slower. It's the same rpm but less distance traveled. Think of it like surface feet oer minute in machining. Even at the same rpm, the speed of the tool changes with diameter. So to have good air flow at all points of the prop it must have different angle of attack closer to the hub where its moving more slowly. Torque has more effect on overall prop surface area.
The horse power conversation was a conversation me and my wife had as we watched this build I had to explain to her the biggest hinderance of actually do this for any feasible flight is basically impossible if I wear to try something like this I’d use a battery type deal with a motor then use a peddle crank to build power while in the air yeah it would still not be a 100% effective to stay in the air but with todays tech you have a good shot of sustaining hour or so
I love the challenge you've thrown down for the whiners. You think this propeller is crap? Fine. Build a better one and send it to me to test. Love it.
Thanks. I watched both videos, but I think you would be better off attaching the chain to the rear wheel and removing the propeller. That way you wouldn’t need to worry about the propeller hitting people.
Hi! If you could find the way how to transfer the rotational energy from spinning rear wheel to propeller shaft, that would give you much more ratio rather than feeding from crankset because the diameter of wheel is bigger than crankset. So, your bicycle would start like normal bicycle (the crankset transfers the rotational energy to your rear wheel via chain), and then your rear wheel would start transmitting the energy to your propeller shaft. How do you like that idea?
I like it. Man powers wheel, wheel powers propeller. In that scenario the rear wheel is basically a flywheel, adding some weight to the diameter of the wheel would give you some centrifugal assistance (to a point) so the wheel would continue to send momentum to the prop even when freewheeling. Hmm. Very interesting idea.
Can you try this with Electric bike with double seperate chain 1 chain will make bike to move forward normally w electric power and u use other chain for propeller with ur foot to gain extra speed and see how much speed it will add to normal electric bike
Clipless pedals and bike shoes are more efficient than street shoes on flat pedals. You could get more power to the propeller for the same effort. Once the bike gets moving, is the relative air speed imparted to the air pushed by the propeller reduced? I don't really know. Maybe the torque required for a given RPM drops? Maybe a couple of gears would actually help.
The questions that got asked forcing you to make another video explaining things makes me scared and concerned that these people are walking around and driving cars?? hahaha How was your first video not blindingly obvious?
I can't stand when people say "hurr why don't you just put a motor on there" Why don't you put a motor on your BRAIN and make THAT go faster? Oh wait, it has to be working in the first place before it can go faster!
A valve train from a Ducati has a bevel gear that would work. quite small, fits into the head of a motorcycle engine. the original photo they definitely had access to an engine with a bevel gear valve train. the propeller could be made much easier to rotate with less surface of the propeller perpendicular to the rotation of the propeller. Much easier
I'd also like to see if the propeller shaft could be driven from the ten speed gearbox at the back of the bike. Start in low gear, then as the propeller gets moving you shift into the higher gears. Still using the bike otherwise as-is, but with more gearing options to drive the propeller shaft.
Or, if you can't connect the gear pack at the back of the bike to the propeller, use a similar concept so that you can make it easier to get the propeller started, and then crank up the gearing once the prop is going. Basically, apply the same logic to the prop, that the regular 10 speed bike applies to the rear wheel.
I cannot believe people are so dumb. Well never mind. I can believe it. But it's annoying. Dude your vids are great. I learn alot. It's entertaining. Screw the stupid people that think they know it all. They don't know anything. You are building. They are sitting on their butt watching RUclips in thier parents basement. Keep it up man.
Paul MacCready solved the issue of human powered flight when he created the Gossamer Condor and Gossamer Albatross in the late 70's. That's where you should start... just copy their propeller design, and maybe see if modern design tools can produce a better version?
This bike was probably made to help win the Kremer prize, a award for first human powered flight set up late 1950’s for 50,000pounds Sterling. It was won by Paul McCready in the Gossomer condor. He later won 100,000 pounds for crossing the English Channel! en.m.wikipedia.org/wiki/Paul_MacCready Paul later designed the EV-1 first modern Electric car body with a super low Cd. The drive train was designed by Allan Coconni . Tesla bought Alan’s design using lithium laptop batteries , since Chevron would not sell him NIMH batteries. That is why a Tesla today has Many cells in series and parallel instead of just a few large ones!
RE: pitch as a function of radius. the main issue isn't the leverage of the torque at different distances, but rather the ratio between the distance that the propeller blade segment travels (2 pi r ; for different r for different segments.) and the forward motion of air through the propeller (also affected by the speed of the bike.) which determines the angle of attack. (more on that later) imagine a large corkscrew going into the ground (like one you would use for wine, a helical structure with an empty center), let's say that with each rotation, it goes 10 inches into the ground, if the circumference of the bounding cylinder is 30 inches, then "slope" of the corkscrew is 3:1. a wider corkscrew with a circumference of 100 inches (but still going 10 inches in) would be at a slope of 10:1 so as you can see, the slope of the propeller to attain the angle of attack (the angle between the airflow and the chord line of the wing) of zero across the entire prop, when the bike is moving forward at the distance of one corkscrew, per revolution. at an angle of attack zero, you are generating zero push (just pinwheeling.) so you want an angle that will give you an optimal angle of attack when the bike at the desired speed. (probably no more than 10 degrees. - this means that at lower speeds you will have a higher angle of attack, and be a lot less efficient in transferring energy to the air.)
The prop design is not 60 years old. It's more like 120+ years old. By 1960 propellers pretty much looked like they do now, a slightly twisted airfoil.
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Using a vintage magazine for inspiration is a great idea, please keep producing more in this series. I think that you did Ernest proud and I wish the project all the best.
I can't believe that you have to make a separate video to explain yourself. I love the videos sir, thanks for the awesome content.
Seriously.
I'm always surprised how many people completely miss the point, even though Jason explained it several times in the original video.
@@pileofstuff keyboard warriors
I was thinking the same thing. Now, how many of those that criticized the original video will actually submit a new design? Genius move by Jason on that part.
the number of people who didnt even understand the project wow. it was so clear he just wanted to have fun buildling a cool thing by recreating something from an image.
meanwhile people: "why didnt you buy it", "put a motor on it", etc
wow those comments, how can so many miss the point of the video.
I appreciate the video but people with all these complaints completely miss the point of these projects. If it were me I wouldn't make a video to address these complaints, they can go kick rocks 🤣. Keep up the great work ! 👍
Its crazy how many people didn't understand the purpose of the original video.
did they skip the intro? fall asleep and wake up with the video playing?
how do people misunderstand building something from a old magazine for fun and education without throwing modern technology on it?
this is an awesome series.
That prop could be optimized a lot! Spin it at a fixed RPM and measure the power using an electric motor and volt and amp meters. Modify to get max RPM at min power, then repeat your experiments. I think that large flat area in the middle parallel to the shaft is just stirring the air, contributing drag and not thrust. FWIW, I think this is a pretty cool experiment, a blast from the past!
I’m amazed how many people didn’t understand the spirit of the video. Love this type of experimentation stuff!
I think you did a GREAT job building it and explaining your rationale. More thought went into designing your project than into all the questions combined.
That’s one way to silence the critics “you think my propeller is naff? Show my how you’d make it better” 👏🏻🙂
I'd love to see some real Computational Fluid Dynamics testing on that shape propeller, and then see how far that design could be pushed without changing the materials or the size, but only the shape.
FWIW, I do tend to agree with others here that the large area in the center that’s parallel to the axis of rotation is just making for more drag. It makes for a simple fab, and avoids strength issues at the root, but it’d be much better if you lopped off a lot of that “vertical” material.
That aside, I imagine that the optimal design (size, pitch, etc) will depend a lot on the characteristics of the particular “motor” 😉 Some people might have their max power output at a higher rpm, others at lower one.
I love your idea I’d having the viewers contribute designs! (!)
Unfortunately, I:
- Don’t have the skills
- Don’t have a slip-roll
- Am currently 100% busy setting up my first metal lathe (woohoo! 🎉)
We still have a competitive yearly self propelled craft into the sea here in England. It's awesome to watch. You covered basically everything in your original video. I'm worried about some of the other subscribers as you had to make this video😅😂ThankQ.TkEZ>UK
Also love that you do this QA for us fans were all builders for the most part so seeing other peoples ideas expands our own ideas plus I like anything that makes me think and learn
I love the Popular Mechanics builds. Too fun. Thanks for all the great content, Jason! Your diplomacy and patience, with the people who made rude or ignorant comments, is incredible. There were moments when it looked like you were grinding your teeth. :)
6:50: That is why airplane propellers blades are twisted up like they are and shaped like clover leaves --- in order to provide uniform airflow over all their cross sections in spite of those differences in air movement at the edges. For that is what you need for efficient propeller-driven flight. Even some large commercial fans are made with propeller-like kinds of fan blades.
I hate it when people dis old designs so many things we use are old designs that don’t need any improvement makes me sad for the future if you never failed you never truly tried
Have to agree, I think that bike looks cool! The fillet welds on the frame are classy!
I really enjoy your videos and I'm excited to see you challenging your critics to put their money where their mouth is. I hope you just keep doing what you have been, you're a great creator.
I love it when you call out the trolls, and I just put in a huge order of popcorn to watch the results!
I'd love to see a race between RUclipsrs on self-made prop bicycles 😂
I like your videos, but some of the things re-explained here are still incorrect.
The pitch of a propeller is steeper at the root because the velocity of the propeller is lower at the centre. It is *not* because of torque limitations. The total diameter of the propeller is usually what is adjusted to limit the torque requirements.
A propeller is a wing, and wings only work properly at a very specific 'angle of attack'. The angle of attack is the relative angle between the blade chord and the oncoming air.
The angle of attack needs to be constant, from root to tip. Because the tip moves faster, it therefore needs to be shallower than the root.
A propeller without twist will only have a narrow 'ring' producing thrust. The root will be too shallow (producing drag) and the tip will be too steep (stalled, making the air turbulent but not accelerating it rearwards).
Good explanation!
Yep! Exactly. I actually just posted this exact explanation and then read yours, so I had to edit and cut it all out. I would be willing to bet the performance of this bike would be increased significantly by a better prop design, as the static lift of a properly shaped wing is considerably more than the dynamic lift. It would have a comical, exaggerated shape, but I think it would work.
Couple thoughts: 1. Use the bike's original gearing to allow you to start the propeller and then shift to get it going faster. 2. There is a lot of surface area that is parallel to the rotation axis. Completely parallel means wasted effort. You could probably improve performance just by cutting some of that area away, as much as possible without making the rest of it floppy.
Not trying to be pedantic, but torque is what you referring to throughout this video. The motor "power" and the human "power" never changes no matter how hard something becomes. The mechanical advantages do change. (torque multiplication)
I love your metal working skills and artistry.
what u accomplished as a result of true to the book is 100% also what you accomplish vid after video is astounding i thought you would not top your last vid then bam and them bam never a dull moment with yoy Jason i would love to have u as a boss LOL respects
I was not asking you to put a motor so you wouldn't have to pedal it, I was really surprised it worked. I meant "put an 80cc two-stroke motor to make it a moped to see if it actually worked as well as the pedal bike with the same motor", like 25-35 mph. I suspected from what you said that it might do quite well, and be a credit to Ernest's propeller, which he actually designed and made, instead of just the bicycle, that he bought at Kmart or Sears, which I appreciated for its design sense and being a steel frame that can hold up all that equipment, flex, and take a weld. The weight and mass is the similar - experience repeated.
You can mount the motor sideways (or up front on the top tube for better balance?) and attach a sprocket and chain to the prop shaft while maintaining the ability to pedal it. Anything which drives the wheels and not the propeller (like an electric hub motor) = stupid and pointless, unless you are trying to test if the airspeed of the moving bike moves the propeller?
If you want speed, get some big motor, but I just wanted to see more testing.
Weld two whistles to the ends to alert pedestrians, but it doesn't seem like there were any people there except your crew.
My only question:
Dear Ernest,
What happens if you pedal backwards - brake, reverse, or nothing?
- Cannot tell me a motor would not help with that test.
And yeah, I did not think you could pedal it sufficient to actually see how good it is; because you said exactly that - there is no control variable, and maybe you get winded on the first ride and flop on the second, and the same with the pro (there are so many types, maybe a long distance or track rider would fare better)? I don't really believe that bicycles are at the level of technical refinement that you say, maybe I should add a variable pitch propeller to my bike?
16-20mph is a pretty good speed for a bike, and everyone is unfamiliar with this thing...
Another Major hardware style fan showdown! I love it!
I can’t believe some of those questions. Great video as always.
Please keep up these projects, you have the patience of Job answering these comments. (Any current deals on slightly used squares that might have some small dings 🙂)
The questions illustrates that they dident hear you, i Got the idea first time.
I love your videos, keep going my friend.
Regards from Denmark 🥰
Great discussion of this difficult engineering problem! Looking forwards to seeing some of the suggestions.
DAMN i thought this was the upgrade video!!!! very well done and cant wait to see how this contraption evolves!
Dear Jason. Don't waste your time on silly comments like the propeller is horrible. Just do what you like, all your constructions are awesome!
nice, thanks, very inspiring! :-)
lots of ideas for optimization - but here are maybe some slightly different considerations:
- more safety! rider protective gear, attach brake to propeller shaft, ... at least paint the propeller's tips bright red for maximum awareness
- did you balance out the propeller? if it requires a lot of filing, you can add varnish to the other blade
- maybe a good way to create a propeller would be to cut open a tube along it's length (actually two half-length cuts, one from each side) and gradually unroll it, starting from the center?
- maybe try some time trial handlebar for more weight towards the front?
- maybe use bike drive chain & front derailleur as 2-speed gear? (then belt for direction)
- toothed belt?
...
.... very nice project :)
The only thing i wanted to see added to the first video was a track cyclist ride it. The guys from indoor track cycling with giant legs who only want to go fast but not necessarily for a long time. I know the first video had an actual cyclist but he is a road rider where endurance is the goal
Think you were right the first time. 'Variable pitch' is set at build but varies along the chord, 'Controllable pitch' is the one you can change in flight, or ride, as it were.
22:21: Yes, Fireball Tool. I fully understand that your propeller bike wasn't meant to be a real bicycle; it was only to test what a propeller can do on a bike. Concepts are nice for people like me who are curious even when those concepts are not practical to everyday life. I am glad you tried it. But now you still might want to keep that propeller bike around for people who want to try it out for themselves as a toy.
Gods...you do so much work and face such headwind. Ever feel like turning off the comments?
Have you considered a lightweight pedal assist on the crank, using a small battery to add and even out torque application between pedal strokes could help you greatly.
Just wanted to say thank you for all the videos.
Because it's such low revolution a third blade would be good to test. Same design as you currently have, just in a Y configuration.
I really like your effort with making this cool bike!
I have actually thought about making a propeller bicycle since many years.
I understand your purpose was to try out a propeller like the one from the old magazine.
But this propeller is horribly inefficient and pushes the most of the air towards the sides instead of backwards. I am very interested to know the result with an efficient and optimized propeller. You would go much faster!
Would be interesting to see how optimized this could get with 60 years of tech and manufacturing advancement...
With no expenses spared you'd think something could be built that would go quite fast. That would be very cool.
I agree! One thing is for sure: it would go much faster!
@@patricj951 Lets place some bets! I think the old man was within 50% (30mph) of modern tech. Ultra light carbon bike with an optimized prop, still wont do better than 30mph or a 50% improvement...
@@beachboardfan9544
I don't understand how you mean. You don't think it will be faster with modern tech and an efficient optimized propeller?
@@patricj951 I do think it will be faster...
I'm speculating on how much faster.
I think Earnest was within 50% improvement. So if his 60s design did 20mph, I think using modern tech/materials, will only yield, at most, a 50% increase in top speed, so no more than 30mph.
Id love to see it with a motor on it, its beyond the idea but still
Maybe submit the idea to famous RUclipsr Colin Furze, thars right up his alley. 😎
That light front end is to help you get off the ground, right? ;)
Great videos as always.
I was thinking that more blades might help. Like adding a third blade, reduce the size of the blades overall to compensate for the additional surface area of the third blade. That's about all I can offer, I am not really at an engineer's level yet.
Your explanation of having to have the prop move "more air" near the hub, isn't exactly correct. On aircraft, the prop tip has a flatter pitch than the hub, because the radius is obviously longer, thus the tip is travelling more distance "around the hub" for each revolution and is thus traveling faster. This also means the tip is traveling "through the air" faster than the cross sections of the blade nearer the hub. The propeller blade behaves like a wing, and to be efficient the flow need to stay attached to the convex side as much as possible. Thus, to keep the flow attached and the prop cross section efficient, the pitch must be decreased as you get further away from the hub. The hub, due to obstructions and the fact it's not operating in "clean" air, is actually the least efficient portion of the propeller.
should have read before writing. yep, getting the propeller to effectively push air, and minimize the drag of the spin, (to require less torque generated by the biker) requires that the angle of attack be optimal on all segments.
1:24 Instead of putting gearbox in the pedal area, you could put one in the propeller shaft instead, it will not require manipulations with the frame. I wonder how more efficient it will be and will it be worth the effort
Where in spokane is this?! So cool to see local channels! Colbert here.
Lol this deserved to be on the main channel
Maybe you could do some sort of collaboration with Furze for some of the mad ideas..Eg: Make it go really fast (make him ride it though and play some great punk music).
I am sure between the two of you the viewers would end up with some great entertainment...
Good presentation. I would like to knitpick one area though. The twisted shape of the prop blades isn't so much to do with torque as it is laminar flow. Closer to the hub, the prop is moving slower. It's the same rpm but less distance traveled. Think of it like surface feet oer minute in machining. Even at the same rpm, the speed of the tool changes with diameter. So to have good air flow at all points of the prop it must have different angle of attack closer to the hub where its moving more slowly. Torque has more effect on overall prop surface area.
The horse power conversation was a conversation me and my wife had as we watched this build I had to explain to her the biggest hinderance of actually do this for any feasible flight is basically impossible if I wear to try something like this I’d use a battery type deal with a motor then use a peddle crank to build power while in the air yeah it would still not be a 100% effective to stay in the air but with todays tech you have a good shot of sustaining hour or so
Add some lightweight solar panels on the wings, doth combined would probably go all day.
@@ravencornell7687 lol love videos like this that make the brain work
simple sollution is to add a gear box/transmision to increase the speed of the prop shaft
I love the challenge you've thrown down for the whiners. You think this propeller is crap? Fine. Build a better one and send it to me to test. Love it.
FIREBALL EXPERIMENTAL AIRCRAFT! It needs to happen.
Fireball tool meets Major Hardware! Do I sense a collab coming in the future? Lol
I wonder if you could use it on the water with some pontoons...
Can you 3d print a propeller to submit? We use 3d printed airfoils for prototyping prior to making tooling then forging them, at my job.
Absolutely
Thanks. I watched both videos, but I think you would be better off attaching the chain to the rear wheel and removing the propeller. That way you wouldn’t need to worry about the propeller hitting people.
Hi! If you could find the way how to transfer the rotational energy from spinning rear wheel to propeller shaft, that would give you much more ratio rather than feeding from crankset because the diameter of wheel is bigger than crankset. So, your bicycle would start like normal bicycle (the crankset transfers the rotational energy to your rear wheel via chain), and then your rear wheel would start transmitting the energy to your propeller shaft. How do you like that idea?
I like it. Man powers wheel, wheel powers propeller. In that scenario the rear wheel is basically a flywheel, adding some weight to the diameter of the wheel would give you some centrifugal assistance (to a point) so the wheel would continue to send momentum to the prop even when freewheeling. Hmm. Very interesting idea.
@@woopimagpie exactly, thanks for detailing the general idea
well, if you want to fly, you do want a little weight in the tail, but you only want the COL just behind the COM
Might be an idea to use a stiffer bicycle frame. This one seems to flex quite a bit.
Luv it…put up or shut up!!!! The gauntlet has been dropped….
Can you try this with Electric bike with double seperate chain 1 chain will make bike to move forward normally w electric power and u use other chain for propeller with ur foot to gain extra speed and see how much speed it will add to normal electric bike
8:46 I hope this is as good as Major Hardware's fan showdown.
Clipless pedals and bike shoes are more efficient than street shoes on flat pedals. You could get more power to the propeller for the same effort.
Once the bike gets moving, is the relative air speed imparted to the air pushed by the propeller reduced? I don't really know. Maybe the torque required for a given RPM drops? Maybe a couple of gears would actually help.
You could possibly loose some drag by removing some metal near the pivot where it's flat
I believe that the Wright Bros used bicycles to test propellers.
The questions that got asked forcing you to make another video explaining things makes me scared and concerned that these people are walking around and driving cars?? hahaha How was your first video not blindingly obvious?
I can't stand when people say "hurr why don't you just put a motor on there"
Why don't you put a motor on your BRAIN and make THAT go faster? Oh wait, it has to be working in the first place before it can go faster!
This sounds like a scaled-up version of the Fan Showdown.
*watches a video about building weird inventions*
"wHy WoUlDn'T yOu JuSt BuY a PrOpElLeR"
All I'm hearing is human powered fan showdown!! I'm so excited.
fan-show-down new design for the 3d printed fan showdown channel.
If you keet the bicycle gearing where it was, and the drive pulley on the other side?
A valve train from a Ducati has a bevel gear that would work. quite small, fits into the head of a motorcycle engine. the original photo they definitely had access to an engine with a bevel gear valve train.
the propeller could be made much easier to rotate with less surface of the propeller perpendicular to the rotation of the propeller. Much easier
I'd also like to see if the propeller shaft could be driven from the ten speed gearbox at the back of the bike. Start in low gear, then as the propeller gets moving you shift into the higher gears. Still using the bike otherwise as-is, but with more gearing options to drive the propeller shaft.
Or, if you can't connect the gear pack at the back of the bike to the propeller, use a similar concept so that you can make it easier to get the propeller started, and then crank up the gearing once the prop is going. Basically, apply the same logic to the prop, that the regular 10 speed bike applies to the rear wheel.
It’s sad you have to answer some of these questions
It must be frustrating answering so many questions relating to people FULLY not understanding the point of these build videos.
Fun! Love to see one built with weed eater motor lol
I think it would be cool to remove those flat spots of proppeler. Cause inthink it makes more drag
can we revisit this bike with an e-propellor bike
I cannot believe people are so dumb. Well never mind. I can believe it. But it's annoying. Dude your vids are great. I learn alot. It's entertaining. Screw the stupid people that think they know it all. They don't know anything. You are building. They are sitting on their butt watching RUclips in thier parents basement. Keep it up man.
Did you just sneak a "I have little legs!" meme into this video?? :D
Paul MacCready solved the issue of human powered flight when he created the Gossamer Condor and Gossamer Albatross in the late 70's. That's where you should start... just copy their propeller design, and maybe see if modern design tools can produce a better version?
LOL , the prop will hit pedestrians.... well derrr.
It would be a great weapon in zombie apocalypse.
@@fitzymagee7469 cringe
@@fitzymagee7469 It's gonna be epic!
@@fitzymagee7469 the peaceful variety, of course. Lol
@@littlejackalo5326 Is there any other kind?
Telling haters to submit their own designs, genius! How many ideas have you got so far?
None
This bike was probably made to help win the Kremer prize, a award for first human powered flight set up late 1950’s for 50,000pounds Sterling.
It was won by Paul McCready in the Gossomer condor.
He later won 100,000 pounds for crossing the English Channel!
en.m.wikipedia.org/wiki/Paul_MacCready
Paul later designed the EV-1 first modern Electric car body with a super low Cd.
The drive train was designed by Allan Coconni . Tesla bought Alan’s design using lithium laptop batteries , since Chevron would not sell him NIMH batteries.
That is why a Tesla today has Many cells in series and parallel instead of just a few large ones!
I think this is the kind of bike that would benefit from a flywheel
So that’s an adjustable pitch prop in aviation terms. A variable pitch is used more like a cvt. Kind of.
Let's see a another upgraded perpulsion craft
RE: pitch as a function of radius.
the main issue isn't the leverage of the torque at different distances, but rather the ratio between the distance that the propeller blade segment travels (2 pi r ; for different r for different segments.) and the forward motion of air through the propeller (also affected by the speed of the bike.) which determines the angle of attack. (more on that later)
imagine a large corkscrew going into the ground (like one you would use for wine, a helical structure with an empty center), let's say that with each rotation, it goes 10 inches into the ground, if the circumference of the bounding cylinder is 30 inches, then "slope" of the corkscrew is 3:1.
a wider corkscrew with a circumference of 100 inches (but still going 10 inches in) would be at a slope of 10:1
so as you can see, the slope of the propeller to attain the angle of attack (the angle between the airflow and the chord line of the wing) of zero across the entire prop, when the bike is moving forward at the distance of one corkscrew, per revolution.
at an angle of attack zero, you are generating zero push (just pinwheeling.) so you want an angle that will give you an optimal angle of attack when the bike at the desired speed. (probably no more than 10 degrees. - this means that at lower speeds you will have a higher angle of attack, and be a lot less efficient in transferring energy to the air.)
what if u make a 4 propeller?
The prop design is not 60 years old. It's more like 120+ years old. By 1960 propellers pretty much looked like they do now, a slightly twisted airfoil.
Other way round, lees pitch for acceleration more pitch for speed
Use hollow shaft instead of solid shaft and light weight propeller of same size
I have my ideas how to make a better prop but no time to build one. Looking forward to what people submit.
how about trying coaxial twin rotors like Kamov helicopters
*5:42** Is this a movie reference? If so, from what movie?*
It's the Terminator ( Arnold Schwarzenegger )
"That is a whole nother video"
Do it
Probá con la cadena conectada