I have only had to release on tow with a CG hook. With a nose hook, I have never even come close to having to release. Set the controls for the conditions before take off roll.
I’m sure you are correct about the tug propwash causing the wing drop, and it’s on the opposite wing to what the glider pilot is expecting to drop in a crosswind. Schempp Hirth talk about this in most of their pilots manuals.
I always tell my students to HOLD the release until the glider is airborne, and then to keep their hand CLOSE to it (To prevent accidental pulling in - say - turbulence over the trees) The second video (The one with the horizontal line) I use in my aerotow briefings as a classic example of why HOLDING the release at the beginning of the launch is neccessary. It's interesting holw long it takes the pilot fumbling for the release. Had it of been in his hand, He could have released a heck of a lot sooner.
In Poland we are taught to predict that propeller wash effect and crosswind effect and to apply controls in advance to counteract those, even before we are fast enough for the effects to occur. Also, I saw wing drop during take off many times at our field and it never ended with release. Few knots more and they were able to raise it with ailerons. However, I saw the guy who caught the high grass with a wing tip and it resulted in the rapid circle. I saw it first hand, I was that guy. It was during landing roll though
Same in France. Theory book and now online training teach the effects of xwind and propwash. Has been national policy for a while to have the hand on the release during the initial tow as well.
Exactly, we are taught about that from the start. It may even be checked either during the license exam or yearly pre-season exam of a local aeroclub. I'm sadly unsure.
Another tip for the wing runner that I'm missing here is that if there is significant force on the wing pushing down when starting the roll, let it come down a little so that the pilot can feel/notice it (even if it's subconsciously) . This will naturally cue the pilot to apply opposite aileron. This feels a little counter-intuitive because it means the pilot has less "distance" to catch the low wing, but if you look at all the videos it seems quite clear that the wing drops as soon as the runner releases it, which means that the pilot just couldn't detect the wing dropping until it was too late. Also, as to incident #3, imho just drop the stupid flag. Stop using it. It's not doing anything other than impeding the wing runner. I know a lot of countries have super elaborate set ups for indicating "take up slack" and "all out" to the pilot, but at least in Germany and the Netherlands (and a few French fields I've seen) the pilot just has a mirror and MAYBE a radio call and it's never been a problem in any launch I've seen.
Hand on the release......so much kit in some of those cockpits, struggled to get to the release. If you are used to changing flaps during the T/O run, keep your hand on the release until you have control authority , then and only then, move your hand from the release to change into positive flap.
Hi, here's pilot n.2 in your list. Taking off after an outlanding, first time there: bad wingman run + gust from the back and yes, trailers pretty close to the runway. Complicated day 😅
The problem isn't that something goes wrong, the glider veers to one side etc. Whatever, the problem is you aren't ready for it. No matter how complicated the day was, keep the hand on the release on takeoff, there's no amount of excuses for not doing that
5:56 You're definetely correct about the offset prop wash. I wasn't taught this in my training either and it took some years until someone explained it to me but now I make sure to pass this on to my stundents when we train aerotows. It's really counter intuitive and catches a lot of pilots by surprise but the windward wing will almost always drop when towing with a significant cross wind. In all other scenarions (e.g. landing or winch launching) it's the other way around. The exact amount depends on the position of the tow plane, strength of the cross wind and length of the rope. 3:52 The Twin Astir has very poor directional stability on the ground when you're not pushing the tail wheel down with the elevator. You can see how "light" the tail is with two pilots in the front and no up elevator applied. This is probably why he's turning right even with the short grass. Interestingly there's not even a visible elevator deflection when the nose comes down due the heavy braking. I'm almost sure aft stick would have prevented the loss of directional control. 5:30 another great way to pronouce Puchacz :)
Regarding the wire disconnect knob, I have never understoond the S-H (Discus B and Arcus I think at least) and Grob logic behind having it in between your legs... It's like the least accessible place in the cockpit in a situation like this, in case you for some reason don't have the hand on the release straight away... I much more appreciate the way it is in AS- aircraft (at least those that I've flown, the K-8 and the K-21), and Ls aircraft. Left side of the cockpit, right by the airbrake lever. In best case scenario you can hold the brake lever shut to ensure even further it doesn't open during launch for whichtever reason, while simultaneously holding to the release knob in case shtf. And if you start without your hand on it, there's still nothing obstructing it ensuring faster operation. Much safer imo.
There is no debate: HAND ON THE RELEASE. Seconds count. Interesting point regarding propwash, however, in the examples you showed, the wing runner wasn't running very fast. Need decent runners with good fitness levels to properly run alongside.
Propwash effect is very noticable at our field behind our more powerful eurofox tug. You start to roll, keep wings level and then about 75-100m into the launch you have to be really on top of it as you get in to the propwash. It's actually easier when doing a runnerless take off, tip wheel on the ground, up slack, hold on full power till you feel the propwash over the glider and then give the all out, off the brakes. Can pick up the tip in just a few metres. Doing the same with a runner, ie waiting till the propwash is established makes countering the effect easier.
I have been tought how to start with no runner in Blanik L-13. But I have learned to go over abort scenarios as part of take off checklist. Different gliders handle wingdrop differently, mainly based on tail construction. So sometimes I keep on going, sometimes I abort.
Thank you ...from ..er..not hinton in the hedges ..total cloud cover at 400meters..arff ..YES i was told prop wash is a big contributor to wing strikes at launch ..i am still learning this , thank you ..your videos are so informative and clear ..a good learning guide indeed .. till my next flight THANK YOU 😊😊😊..
Hey your theory seems true, it’s described in our Polish gliding books from 70’ and 80’, and it’s obligatory to know that to get glider license. On windy days, just before start, my instructor was always asking which wing will go up, which direction nose will go and which controls I’m applying before start to counteract that. Note that aileron is different for winch launch and tow!
A very useful video, as usual, thanks a lot for sharing! Having owned for 12 years an ASW15 with the offset CG hook I understand far too well the problem. My worst takeoff ever behind a Maule (very powerful taildragger) in strong right crosswind on a concrete runway. Lethal combination. Next take offs I asked for a Robin.😂 First (AS?) and second (DG) glider in the video appear to have belly (CG) hooks, which explains a lot imho. Anyway, always hand on release and ready to use it. Thanks again, Tim
I have a 15B which has both the offset CG hook and an aerotow hook just forward of the instrument panel base. Since we only do aerotow where I fly I've always used the forward hook but I figured there was a chance that someday I would get hooked up with the CG hook and not notice until the all-out so I had better try it so I know what it's like. We have a wide grass field, seldom get much crosswind component at all and my glider has the roller-blade wheel instead of a hard skid and it was still pretty impressive how much of a swing to the right I got when the L-19 towplane accelerated. I can just imagine what a handful it could be in a less benign situation.
Interesting note on the crosswind pushing the prop wash... I was flying in Germany earlier this year and noticed that the tow ropes they were using seemed quite a bit shorter than what we tow with in the US.
In each case we didn’t see much use of the rudder. A quick boot of full opposite rudder does a lot to lift a dropped wing. It would have been really noticeable in the Puchacz with that big effective rudder.
I had almost the exact same thing as the first clip earlier this season, though it was an aero retrieve out of a narrow strip with no wing runner. Safe to say I was glad I was wearing my brown pants that day!
First one, Std Cirrus with a cg hook and a tailskid on a hard runway. Always gonna be a challenge, almost zero directional stability. Second one, DG, so would have a tailwheel, good aileron authority, just careless. Puchacz, the one we had always tried to drop it's right wing as the nose wheel was lifted to balance on main wheel, never actually managed to drag a wingtip though. Tip skid designs can have a lot to answer for.
In my HPH304 MS, the tow release is on the floor almost under my leg. When I aero tow, I always make sure it is in a place where I can get it. The problem is with the use of negative flaps on initial role, my left hand is busy on the flap lever and I have to switch to the release handle I understand that now, the European ships are coming out with the tow release, mounted on the lower left corner of the panel where it is available. I wish I could change mine.
Not sure this would of helped here but: When I ran wings I would hold a heavy wing low and a light wing high so the pilot would have the correct aileron input in when I realized the wing.
@pureglide You're flying a Ventus 2T, right? Quoting from the Ventus 2cxT flight manual on Aero Tow: "With croswind, deflect the ailerons away from the wind to compensate for the deflected prop wash" ;)
I used to own a Lak-12 which was known to have poor aileron authority at low speeds, but assisted with 2 notches of negative (upward) flap. I was always towed up by a Super Diamona, and I never experienced wing drop. Possibly because of the lower volume of prop-wash, but also I had the habit in crosswinds of sneaking slightly downwind of the tug immediately ground roll started. I don't know why I have always done this, I was never told to, but it seemed as if that is what should be done, and then when airborne weathercock to maintain track, and once the tug is airborne, you are right in station. If this is a bad idea, tell me. I was wanting to go onto winch, as you are airborne before you can say "blast off" with those incredible things. And if your wing drops before airborne, no thinking .... you pull the plug or risk death. I never did get to winch launch in it. Now I recently read that a Lak 12 in NZ recently broke up on a winch launch. Can you look at that that one, please?
ive been flying an (open) cirrus on aerotow on a narrow runway for a while, its fine but needs some extra care. in mine ,it takes a bit to get rudder authority and be mindful not to kite the launch( trim forward and stay below tug ) my cfi had me fly the 2 seater on belly hook with trim back to help with this.
Only witnessed one serious ground loop, and of course it was a Discus. :D But I like the theory about the prop wash, I'll try to think about that next time I go flying.
Also wing runners - Can I suggest open palm slap the wing to get the pilot's attention if you can feel an up/down force before up slack (don't give it yet), point in the direction of the force when you've got the pilot's attention so they can adjust the ailerons, and thumb up to them when it's right.
Am I right that the first one is a Std Cirrus? If not ignore. If so, they have poor aileron control on the start of an aerotow ground run - especially the earliest ones before they increased the washout (like the one I had long ago). Things that helped: 1) airbrakes open at the start of the ground run 2) if there is room use the rudder to pick up the wing 3) (and best of all) replace the top surface only TESA with both surface mylar - the ailerons are top hinged and have a draggy opeing on the bottom surface when the aileron is up.
Hand on the release? As soon as I was taught winch launch I was told to have it near the release so on ground I could grab the brakes fast or the release, depending on what's deemed more necessairy I mean I get why on the release but why so different approaches towards launching?
If you need to use the release, you have almost no chance of grabbing it if you don't keep your hand on it. It happens in a fraction of a second, and your body and hand will be violently thrown around. There’s no chance to grab it. You will need the airbrakes in case of a cable break, but that won’t happen instantly because you first need to lower the nose, regain speed, and then open the airbrakes. You’ll have enough time to move your hand from the release to the airbrakes.
I wonder also if there's some kind of P-factor occuring as the spiraling propwash from the tow-plane intersects the wing of the glider behind, creating different effective angles of attack on the left vs right wing and thus different amounts of lift?
Good theory. In that case it should be more apparent in calm conditions. It is probably more likely it is the increase in V-squared's travelling over the downwind wing as Tim stated.
Bang on right about propwash. Some gliders are more prone to this than others, my Libelle H201 being one of them. Never an issue behind the Citabria 150hp, but behind the Pawnee 230hp I've had a few wing drops from it, and the nose release and wheels on the wing tip I'm able to get it back up very quickly (while also grabbing for the release). What I do find helps is to use a slightly longer rope. A 200' rope is ok, but 150' rope I'm more than likely to have a crosswind blow propwash into one wing, unless you are offset and ready to account for it.
Indeed the prop wash hits the leeward wing, which then creates lift. Add some weathercock effect on the vertical tail and it often gets hard to avoid dropping the windward wing tip and turning hard into the wind. I wonder why it isn't a SOP to always apply aileron leeward before starting the takeoff run. It is SOP in Open Class gliders which otherwise are nearly impossible to balance in a crosswind.
One time in my ASW 20 with only CG hook. It went sideways in a nano second. I immediately pulled release, then spent 200 yards going through the grass on the side of the runway. No damage but I gave me respect, and now I leave flaps at 1 until 45 to 50 knots and start with airbrakes open.
In our slightly narrow airstrip (50m between the poles) we usually start with full ailerons opposite to the crosswind direction... Sometimes prop-wash is so strong, that even starting with full ailerons, first meters you just wait (and pray :) ) ..... And even then - wing start to drop against the aileron... Yes, lifting the tail as early as you can, helps to achive more effective aileron control...
Tim, have you ever been a wing runner '& had the wing rip out of your hand, & the tip goes to the ground, please don't blame the wing runner, ps no ground loop, maybe i held on for just long enough, but it was scary!
To long grass is allways a problen .In a field, I landed in riverse after hitting tall ( maybe 50cm /20 inches) long grass with one wing, was stopped in 50 meters but my fuselage was broken .
Always have at least 2 fingers on the release so you don't have to go looking for it when you need it. I've been an automotive functional safety engineer and my take is: If there is any moment during launch where an accidental release leads to an unavoidable accident (glider damage, injuries) then there shouldn't be a "Hand on release" debate. The functional safety of the entire launch is flawed and needs to be revised. If there isn't some kind of redundancy for every stage of your flight, you shouldn't fly. That's basically what Tim meant when he said there's no reason to launch next to a fence or a line of trailers.
Most gliders don't have suspension and launch from bumpy nature strips, so unintentional releases on ground run are not unheard of, worst if they happen just before you get aileron authority. Shortly after takeoff if there are no good landables in front you as well inevitably endanger the flight by holding your hand on the release as unintentional releases happen in turbulent conditions. So this is always a fine balance and a local knowledge involved in decision to hold close/hold onto release. At our airfield we always teach students to hold hand close to release because of limited options straight ahead on aerotow. Winch is much better in this sense as by the time you run out of runway ahead you already have enough height for a safe landing back. Other clubs have unfenced paddocks straight after runway end and that takes out so much pressure, you can safely hold onto release all your way until you pull it up high.
The first glider looks like a Standard Cirrus. It has a gear hook, so running the wing properly is crucial, and here it was very likely released too early.
Sage advice. You want to be able to release as instantly as you can and be able to stop quickly if necessary. A lot of gliders don’t make that particularly easy with the cockpit ergonomics - quite a few flapped machines make it difficult to access the release as it’s almost hidden when in reflex settings and in others you have to lean forward and stretch to get at it and as in one of the vids, if the glider is bouncing it can be a) hard to get hold of and b) you instinctively look for it which means you’re not controlling the glider by looking outside at that moment. I occasionally fly gliders with these issues and make a DIY extension to the release which is easy to grab, like a piece of rope/cloth. It’s possible to actually have it in your hand so a quick yank is all that is required rather than a fumble. I have a theory that some aborted takeoffs turn into accidents because the pilot is so busy flailing around in the cockpit they forget to steer the aeroplane (or bring it smartly to a halt)...
6:15 at that instant I performed the Leonardo Di Caprio pointing at the tv meme. I haven't touched a glider for almost a decade now, but still remember that phenomenon from my training -- see other comments from my polish collegues. #4 almost didn't touch the rudder, I think.
In France - hand on the release or you will flunck your SPL, your check-ride or whatever, it is not debateable. Propwash in crosswind is a no-brainer, also taught from the beginning to expect it.
I've got a Standard Cirrus (clip 1), similar configuration with belly hook only and probably tail skid. Based on them doing any ground roll in that thing without being on the release the whole time, I'm guessing they haven't owned it for very long!
When I was still gliding, we had another possible reason of wingdrop. The walkers (often also student pilots still) are told to firmly hold the wing level. If this is the side where wind is coming from the pilot favors this side to be a bit down. When the walker release this the pilot could have enough aileron input for that side to fall down
I remember handling the crosswind component with a bit of slip into the wind (and we had some pretty severe crosswinds at California City). However, these tow ropes also seem pretty short, which would definitely put them into the propwash. Curious if people think this may be true. Great video!
Irrespective of the launch method. Always have your hand on the release. Release if you cannot keep the wings level. Inconvenience of re-launching is always better than that involving the insurance companies and the work shop. The issue is people, as some have mentioned below you usually get away with it, one day you will not.
Totally agree. You‘ll also find several videos on rope break exercices where the pilot grabs twice for the release handle as it starts to move at 0g and he misses it the first time. In case of an execice that‘s no problem. If the cable breaks some feet below you, the rope might snap up if not released quickly. And if you drop a wing in a winch launch, you have even less time to react than in aerotow.
I saw your theory on prop wash. I was thinking about that earlier in the video, are there often many issues relating to prop wash? Is there a technique to avoid the affects?
Third example: the wing man was really lazy, but I feel that in this case, the pilot possibly should nor have released, because the tow line would pull the glider towards the center (nose hook). Also, when the line was released, the aileron was neutral for about 2 seconds (when you release, you loose control of other things...). It really looked like the glider was recoverable, if it were not for the loss of roll control for 2 seconds... i wonder did he had his hand on the release, or started fumbling around and lost controll of the roll when he tried to grab the release?
As someone that has flown from that runway I can confirm that is not the case. I had something similar happen to me with a crosswind and was further down the strip (not near the fence) and I couldn't get the tip off the ground in an ASK21. Probably something do with the terrain and structures around that end of the airfield. The club has a lot of older members so I don't think laziness has anything to do with it.
@PureGlide yes. It was particularly nasty since we didn't brief this kind of thing. I managed to pick up the wing, but I was happy to have a nose hook and tail wheel.
Tim! The wing drop dur to prop wash is not a theory. It is a well-known fact (at least in Poland). We learn this during our basic aerotow training and it is well described in books published 50(!) years ago. Please spread the word as I find it very important for safe aerotow launch. The wind direction is` the first thing I check before aerotow launch and I even apply some counter-aileron correction before take-off.
It looks as if some crude use of the rudder (rudder deflection) to help keep the glider on track, caused as a secondary effect, roll to the left, causing the port-wing to drop and catch in the grass (first incident)
Tim, we both fly the Ventus cT and use negative flap at the start of the ground run - just when there’s the risk of wing drop. How do you manage, without having two left hands?
Question: having been trained to do a wing down launch, this seems to be at odds with the advice to abort if the wing drops… I’d appreciate any advice here.
Yeah that is a useful skill to be able to do, sometimes it's the only option. But conditions have to be good to do it, e.g. 15m glider, short grass etc. Good prop wash over the wings helps get control early. Or a good head wind. I never do them with my 18m wingspan... I'm pretty sure I've had to bung off attempting a couple too... so I'd consider it an advanced thing to do. And don't do it near the fence!
I've heard that gliders aero towing with GC hooks are more prone to losing directional control on the initial ground roll. Any truth to this ? I have a release extension,so that the release is on my lap. With full stick deflection to the left, it is impossible to grab the release otherwise. Adding to that, I am flying a flapped glider, so my left hand is on the flap lever until airborne.
Yes absolutely, because a nose hook is actively pulling the glider into alignment, while a belly hook requires to be flown in the right direction. It won’t auto correct itself if you start going off on an angle
I have a question. Have been thinking whether to join a gliding club. I don't have flying experience, but have spent time learning essential theory. But, to my question ... I've noticed there is fair bit of "banter" in aviation. Having watched the TV aircraft accident programs, I estimate one-third have psychology as a factor, where someone in the cockpit was intimidated by rank seniority and not performing to task. Don't get me wrong -- I'm not complaining to avoid critique. I'm asking whether the critique is chronic.
Ok, so with a crosswind takeoff you can have differential lift which forces one wing up and the opposite wing down. So, should that affect choice of which wing your wing-runner is operating from?
When I was instructing the thing we used to consider was that a crosswind was likely to make the glider weathercock at low speed. The wing-holder could counteract this by slightly holding back on the wing at the beginning of the take-off run. But you need to take into account all sorts of variables, including the power of the tug and the size and weight of the glider, and different considerations might apply with a winch launch. And of course an experienced ground crew could predict which wing might be likely to drop and counteract that by keeping one wing higher than the other. Good ground crew are very valuable. But I flew at a massive airfield with very wide runways. It was a very forgiving environment, but you get complacent at your peril.
The theory goes that it spills the air outboard over the ailerons, increasing their effectiveness. Or, the drag and on some types wheel brake means you delay the start of the ground roll a little bit and so the wing runner is still holding your wing until the tug is developing full power. Personally, as an instructor and tug pilot, I don't like it, and think that your hand should be on the release and not on the airbrake.
Some pilots are also too lazy to fly the aircraft while stationary on the ground. As a wing runner you then have to give to much force to keep it level. Then when letting it go the wing drops. Surprise? NO. As a wing runner you should apply minimal force, and let the pilot do its job. But some pilot just don't get it that they need to do stuff even when stationary just for take-off.
Hello! I thought you handled the ground loop very well. Thank you for sharing the video, it's a great lesson for people how quickly it can happen. I added a link in the description to your original video. Cheers
What does? The gliders that have one wheel in front are probably MORE stable at low speeds because of it. Or do you mean because we only have one main wheel? I don't think that's very different from a taildragger, if at all.
7:03 You should never have your hand on the release on a winch launch because you could accidentaly pull it. In Germany they teach use to have it really close to the realease but never on it
Dont you mean always have your hand on the release during a winch launch? Accidental release is recoverable at all stages if flown correctly. Any delay in releasing is likely to result in crash if catching a wing tip as it will enter an uncontrollable cartwheel.
@@david3599 it doesnt take long to pull the release its almost as fast as if your hand is on it because its right next to it so there is almost no delay you just have to be ready and prepared. The problem wit accidental release is that if you fly it right its recoverable but its always a high risk. Humans make mistakes so maybe u messed up the launch and pitched up to steep and then released or you make a mistake after the rope releases and crash then. So i think having the hand really close to the release makes it so you can still release quickly but you also avoid the risk that would come with a accidental release
I might make a video about this, and almost did cover it in this video. I argue hand should always be ON release with a winch launch. Any delay could be fatal or catastrophic with a cartwheel as it happens so fast. Releasing accidentally is very unlikely to be fatal, especially while bumping along the ground at the start. Also it could happen anytime with a rope break.
@@PureGlide If your hand is near the Rope release it almost doesnt delay it. Releasing accidental is like a ropebreak but ropebreaks can be very dangerous even if trained so thats not good. I know its pretty unlikely to happen but in my club it already happened. I think the risk is higher if the rope release isnt a ball but has a T shape
If you search for British Gliding Association safe winch launching they clearly state on the website: Start the launch with your hand on the release. Why hand on the release? Because you need to pull the release within half a second of taking the decision to release. Why immediately? Because the cartwheel that may follow a wing drop onto the ground can be so rapid that no recovery by releasing or other means is possible. If you have alternative official information, please do share the source.
Always, hand on the release. Did I mention hand on the release? Thanks, Tim!
I have only had to release on tow with a CG hook. With a nose hook, I have never even come close to having to release. Set the controls for the conditions before take off roll.
You could empty a couple of buckets of prop wash on the other wing before takeoff to counter the wash that gets pushed over by the x wind 🤔
I like your thinking!
In Poland the crosswind prow wash effect question is part of the theory exam, before you flying,
I’m sure you are correct about the tug propwash causing the wing drop, and it’s on the opposite wing to what the glider pilot is expecting to drop in a crosswind. Schempp Hirth talk about this in most of their pilots manuals.
I always tell my students to HOLD the release until the glider is airborne, and then to keep their hand CLOSE to it (To prevent accidental pulling in - say - turbulence over the trees) The second video (The one with the horizontal line) I use in my aerotow briefings as a classic example of why HOLDING the release at the beginning of the launch is neccessary. It's interesting holw long it takes the pilot fumbling for the release. Had it of been in his hand, He could have released a heck of a lot sooner.
In Poland we are taught to predict that propeller wash effect and crosswind effect and to apply controls in advance to counteract those, even before we are fast enough for the effects to occur.
Also, I saw wing drop during take off many times at our field and it never ended with release. Few knots more and they were able to raise it with ailerons.
However, I saw the guy who caught the high grass with a wing tip and it resulted in the rapid circle. I saw it first hand, I was that guy. It was during landing roll though
Same in France. Theory book and now online training teach the effects of xwind and propwash. Has been national policy for a while to have the hand on the release during the initial tow as well.
Exactly, we are taught about that from the start. It may even be checked either during the license exam or yearly pre-season exam of a local aeroclub. I'm sadly unsure.
@@urlichwichmann6456 or both, perhaps
Another tip for the wing runner that I'm missing here is that if there is significant force on the wing pushing down when starting the roll, let it come down a little so that the pilot can feel/notice it (even if it's subconsciously) . This will naturally cue the pilot to apply opposite aileron. This feels a little counter-intuitive because it means the pilot has less "distance" to catch the low wing, but if you look at all the videos it seems quite clear that the wing drops as soon as the runner releases it, which means that the pilot just couldn't detect the wing dropping until it was too late.
Also, as to incident #3, imho just drop the stupid flag. Stop using it. It's not doing anything other than impeding the wing runner. I know a lot of countries have super elaborate set ups for indicating "take up slack" and "all out" to the pilot, but at least in Germany and the Netherlands (and a few French fields I've seen) the pilot just has a mirror and MAYBE a radio call and it's never been a problem in any launch I've seen.
Hand on the release......so much kit in some of those cockpits, struggled to get to the release.
If you are used to changing flaps during the T/O run, keep your hand on the release until you have control authority , then and only then, move your hand from the release to change into positive flap.
Hi, here's pilot n.2 in your list. Taking off after an outlanding, first time there: bad wingman run + gust from the back and yes, trailers pretty close to the runway. Complicated day 😅
thanks for the contribution. Every bit of information helps.
>> gust from the back
So they took off with a tail wind? STUPID!
You didn't mention you didn't have your HAND ON THE RELEASE
The problem isn't that something goes wrong, the glider veers to one side etc. Whatever, the problem is you aren't ready for it. No matter how complicated the day was, keep the hand on the release on takeoff, there's no amount of excuses for not doing that
5:56 You're definetely correct about the offset prop wash. I wasn't taught this in my training either and it took some years until someone explained it to me but now I make sure to pass this on to my stundents when we train aerotows. It's really counter intuitive and catches a lot of pilots by surprise but the windward wing will almost always drop when towing with a significant cross wind. In all other scenarions (e.g. landing or winch launching) it's the other way around. The exact amount depends on the position of the tow plane, strength of the cross wind and length of the rope.
3:52 The Twin Astir has very poor directional stability on the ground when you're not pushing the tail wheel down with the elevator. You can see how "light" the tail is with two pilots in the front and no up elevator applied. This is probably why he's turning right even with the short grass. Interestingly there's not even a visible elevator deflection when the nose comes down due the heavy braking. I'm almost sure aft stick would have prevented the loss of directional control.
5:30 another great way to pronouce Puchacz :)
At my club, the glider is always offset up wind of the tug during crosswind takeoff to minimize propwash over the wing.
always nice to see a Twin and feel the pain in the arms
Mit beiden Armen, bis sie erlahmen....
Regarding the wire disconnect knob, I have never understoond the S-H (Discus B and Arcus I think at least) and Grob logic behind having it in between your legs... It's like the least accessible place in the cockpit in a situation like this, in case you for some reason don't have the hand on the release straight away...
I much more appreciate the way it is in AS- aircraft (at least those that I've flown, the K-8 and the K-21), and Ls aircraft. Left side of the cockpit, right by the airbrake lever. In best case scenario you can hold the brake lever shut to ensure even further it doesn't open during launch for whichtever reason, while simultaneously holding to the release knob in case shtf. And if you start without your hand on it, there's still nothing obstructing it ensuring faster operation. Much safer imo.
There is no debate: HAND ON THE RELEASE. Seconds count.
Interesting point regarding propwash, however, in the examples you showed, the wing runner wasn't running very fast. Need decent runners with good fitness levels to properly run alongside.
I recognise Boonah airfield in the clip, I flew out of there for years. ( powered fixed wing).
Propwash effect is very noticable at our field behind our more powerful eurofox tug. You start to roll, keep wings level and then about 75-100m into the launch you have to be really on top of it as you get in to the propwash.
It's actually easier when doing a runnerless take off, tip wheel on the ground, up slack, hold on full power till you feel the propwash over the glider and then give the all out, off the brakes. Can pick up the tip in just a few metres.
Doing the same with a runner, ie waiting till the propwash is established makes countering the effect easier.
I have been tought how to start with no runner in Blanik L-13. But I have learned to go over abort scenarios as part of take off checklist. Different gliders handle wingdrop differently, mainly based on tail construction. So sometimes I keep on going, sometimes I abort.
The tip about the propwash is a big one. I had never heard of it before, but it seems to make sense. I will watch this a couple of more times.
Thank you ...from ..er..not hinton in the hedges ..total cloud cover at 400meters..arff ..YES i was told prop wash is a big contributor to wing strikes at launch ..i am still learning this , thank you ..your videos are so informative and clear ..a good learning guide indeed .. till my next flight THANK YOU 😊😊😊..
Hey your theory seems true, it’s described in our Polish gliding books from 70’ and 80’, and it’s obligatory to know that to get glider license. On windy days, just before start, my instructor was always asking which wing will go up, which direction nose will go and which controls I’m applying before start to counteract that. Note that aileron is different for winch launch and tow!
A very useful video, as usual, thanks a lot for sharing!
Having owned for 12 years an ASW15 with the offset CG hook I understand far too well the problem.
My worst takeoff ever behind a Maule (very powerful taildragger) in strong right crosswind on a concrete runway. Lethal combination.
Next take offs I asked for a Robin.😂
First (AS?) and second (DG) glider in the video appear to have belly (CG) hooks, which explains a lot imho.
Anyway, always hand on release and ready to use it.
Thanks again, Tim
I have a 15B which has both the offset CG hook and an aerotow hook just forward of the instrument panel base. Since we only do aerotow where I fly I've always used the forward hook but I figured there was a chance that someday I would get hooked up with the CG hook and not notice until the all-out so I had better try it so I know what it's like. We have a wide grass field, seldom get much crosswind component at all and my glider has the roller-blade wheel instead of a hard skid and it was still pretty impressive how much of a swing to the right I got when the L-19 towplane accelerated. I can just imagine what a handful it could be in a less benign situation.
Interesting note on the crosswind pushing the prop wash... I was flying in Germany earlier this year and noticed that the tow ropes they were using seemed quite a bit shorter than what we tow with in the US.
In each case we didn’t see much use of the rudder. A quick boot of full opposite rudder does a lot to lift a dropped wing. It would have been really noticeable in the Puchacz with that big effective rudder.
I had almost the exact same thing as the first clip earlier this season, though it was an aero retrieve out of a narrow strip with no wing runner. Safe to say I was glad I was wearing my brown pants that day!
First one, Std Cirrus with a cg hook and a tailskid on a hard runway. Always gonna be a challenge, almost zero directional stability.
Second one, DG, so would have a tailwheel, good aileron authority, just careless.
Puchacz, the one we had always tried to drop it's right wing as the nose wheel was lifted to balance on main wheel, never actually managed to drag a wingtip though.
Tip skid designs can have a lot to answer for.
In my HPH304 MS, the tow release is on the floor almost under my leg. When I aero tow, I always make sure it is in a place where I can get it. The problem is with the use of negative flaps on initial role, my left hand is busy on the flap lever and I have to switch to the release handle
I understand that now, the European ships are coming out with the tow release, mounted on the lower left corner of the panel where it is available. I wish I could change mine.
Not sure this would of helped here but:
When I ran wings I would hold a heavy wing low and a light wing high so the pilot would have the correct aileron input in when I realized the wing.
Loved the video, love the theory!
@pureglide You're flying a Ventus 2T, right? Quoting from the Ventus 2cxT flight manual on Aero Tow: "With croswind, deflect the ailerons away from the wind to compensate for the deflected prop wash" ;)
Sadly not, I'm a Ventus cT, so never got that bit of the manual!
@@PureGlide We can't all have a V2ct, but hey, *you* have got like 10 different wing tips, lucky you!
I used to own a Lak-12 which was known to have poor aileron authority at low speeds, but assisted with 2 notches of negative (upward) flap. I was always towed up by a Super Diamona, and I never experienced wing drop. Possibly because of the lower volume of prop-wash, but also I had the habit in crosswinds of sneaking slightly downwind of the tug immediately ground roll started. I don't know why I have always done this, I was never told to, but it seemed as if that is what should be done, and then when airborne weathercock to maintain track, and once the tug is airborne, you are right in station. If this is a bad idea, tell me. I was wanting to go onto winch, as you are airborne before you can say "blast off" with those incredible things. And if your wing drops before airborne, no thinking .... you pull the plug or risk death. I never did get to winch launch in it. Now I recently read that a Lak 12 in NZ recently broke up on a winch launch. Can you look at that that one, please?
I’m about to check out in my first CG hook glider so, this topic is front of mind for me.
ive been flying an (open) cirrus on aerotow on a narrow runway for a while, its fine but needs some extra care. in mine ,it takes a bit to get rudder authority and be mindful not to kite the launch( trim forward and stay below tug ) my cfi had me fly the 2 seater on belly hook with trim back to help with this.
Only witnessed one serious ground loop, and of course it was a Discus. :D But I like the theory about the prop wash, I'll try to think about that next time I go flying.
A good proper preflight with wing runner is not a bad idea.
Also wing runners - Can I suggest open palm slap the wing to get the pilot's attention if you can feel an up/down force before up slack (don't give it yet), point in the direction of the force when you've got the pilot's attention so they can adjust the ailerons, and thumb up to them when it's right.
One time I was able to keep wings level on ground for about a minute without wing runner, only with just the wind.
Thanks for sharing your thoughts making it interesting
Am I right that the first one is a Std Cirrus? If not ignore. If so, they have poor aileron control on the start of an aerotow ground run - especially the earliest ones before they increased the washout (like the one I had long ago). Things that helped: 1) airbrakes open at the start of the ground run 2) if there is room use the rudder to pick up the wing 3) (and best of all) replace the top surface only TESA with both surface mylar - the ailerons are top hinged and have a draggy opeing on the bottom surface when the aileron is up.
Hand on the release? As soon as I was taught winch launch I was told to have it near the release so on ground I could grab the brakes fast or the release, depending on what's deemed more necessairy
I mean I get why on the release but why so different approaches towards launching?
If you need to use the release, you have almost no chance of grabbing it if you don't keep your hand on it. It happens in a fraction of a second, and your body and hand will be violently thrown around. There’s no chance to grab it. You will need the airbrakes in case of a cable break, but that won’t happen instantly because you first need to lower the nose, regain speed, and then open the airbrakes. You’ll have enough time to move your hand from the release to the airbrakes.
I wonder also if there's some kind of P-factor occuring as the spiraling propwash from the tow-plane intersects the wing of the glider behind, creating different effective angles of attack on the left vs right wing and thus different amounts of lift?
maybe!
Good theory. In that case it should be more apparent in calm conditions. It is probably more likely it is the increase in V-squared's travelling over the downwind wing as Tim stated.
NOPE..
Bang on right about propwash. Some gliders are more prone to this than others, my Libelle H201 being one of them. Never an issue behind the Citabria 150hp, but behind the Pawnee 230hp I've had a few wing drops from it, and the nose release and wheels on the wing tip I'm able to get it back up very quickly (while also grabbing for the release). What I do find helps is to use a slightly longer rope. A 200' rope is ok, but 150' rope I'm more than likely to have a crosswind blow propwash into one wing, unless you are offset and ready to account for it.
Indeed the prop wash hits the leeward wing, which then creates lift. Add some weathercock effect on the vertical tail and it often gets hard to avoid dropping the windward wing tip and turning hard into the wind.
I wonder why it isn't a SOP to always apply aileron leeward before starting the takeoff run. It is SOP in Open Class gliders which otherwise are nearly impossible to balance in a crosswind.
@PureGlide >>> Great video...👍
One time in my ASW 20 with only CG hook. It went sideways in a nano second. I immediately pulled release, then spent 200 yards going through the grass on the side of the runway. No damage but I gave me respect, and now I leave flaps at 1 until 45 to 50 knots and start with airbrakes open.
Thank You, Tim, for these interesting reviews. Safety is always first.
In our slightly narrow airstrip (50m between the poles) we usually start with full ailerons opposite to the crosswind direction... Sometimes prop-wash is so strong, that even starting with full ailerons, first meters you just wait (and pray :) ) ..... And even then - wing start to drop against the aileron... Yes, lifting the tail as early as you can, helps to achive more effective aileron control...
Tim, have you ever been a wing runner '& had the wing rip out of your hand, & the tip goes to the ground, please don't blame the wing runner, ps no ground loop, maybe i held on for just long enough, but it was scary!
That's what I'm saying, sometimes it has a lot of pressure, and I explained my theory why in the video.
To long grass is allways a problen .In a field, I landed in riverse after hitting tall ( maybe 50cm /20 inches) long grass with one wing, was stopped in 50 meters but my fuselage was broken .
Always have at least 2 fingers on the release so you don't have to go looking for it when you need it.
I've been an automotive functional safety engineer and my take is: If there is any moment during launch where an accidental release leads to an unavoidable accident (glider damage, injuries) then there shouldn't be a "Hand on release" debate. The functional safety of the entire launch is flawed and needs to be revised. If there isn't some kind of redundancy for every stage of your flight, you shouldn't fly. That's basically what Tim meant when he said there's no reason to launch next to a fence or a line of trailers.
Most gliders don't have suspension and launch from bumpy nature strips, so unintentional releases on ground run are not unheard of, worst if they happen just before you get aileron authority. Shortly after takeoff if there are no good landables in front you as well inevitably endanger the flight by holding your hand on the release as unintentional releases happen in turbulent conditions. So this is always a fine balance and a local knowledge involved in decision to hold close/hold onto release. At our airfield we always teach students to hold hand close to release because of limited options straight ahead on aerotow. Winch is much better in this sense as by the time you run out of runway ahead you already have enough height for a safe landing back. Other clubs have unfenced paddocks straight after runway end and that takes out so much pressure, you can safely hold onto release all your way until you pull it up high.
The first glider looks like a Standard Cirrus. It has a gear hook, so running the wing properly is crucial, and here it was very likely released too early.
Sage advice. You want to be able to release as instantly as you can and be able to stop quickly if necessary. A lot of gliders don’t make that particularly easy with the cockpit ergonomics - quite a few flapped machines make it difficult to access the release as it’s almost hidden when in reflex settings and in others you have to lean forward and stretch to get at it and as in one of the vids, if the glider is bouncing it can be a) hard to get hold of and b) you instinctively look for it which means you’re not controlling the glider by looking outside at that moment.
I occasionally fly gliders with these issues and make a DIY extension to the release which is easy to grab, like a piece of rope/cloth. It’s possible to actually have it in your hand so a quick yank is all that is required rather than a fumble. I have a theory that some aborted takeoffs turn into accidents because the pilot is so busy flailing around in the cockpit they forget to steer the aeroplane (or bring it smartly to a halt)...
Solution for Accident #3: Never use the oldest guy on the field to be the Wingrunner...
6:15 at that instant I performed the Leonardo Di Caprio pointing at the tv meme. I haven't touched a glider for almost a decade now, but still remember that phenomenon from my training -- see other comments from my polish collegues.
#4 almost didn't touch the rudder, I think.
In France - hand on the release or you will flunck your SPL, your check-ride or whatever, it is not debateable. Propwash in crosswind is a no-brainer, also taught from the beginning to expect it.
That is good!
I've got a Standard Cirrus (clip 1), similar configuration with belly hook only and probably tail skid. Based on them doing any ground roll in that thing without being on the release the whole time, I'm guessing they haven't owned it for very long!
When I was still gliding, we had another possible reason of wingdrop. The walkers (often also student pilots still) are told to firmly hold the wing level. If this is the side where wind is coming from the pilot favors this side to be a bit down. When the walker release this the pilot could have enough aileron input for that side to fall down
I remember handling the crosswind component with a bit of slip into the wind (and we had some pretty severe crosswinds at California City). However, these tow ropes also seem pretty short, which would definitely put them into the propwash. Curious if people think this may be true. Great video!
Irrespective of the launch method. Always have your hand on the release. Release if you cannot keep the wings level. Inconvenience of re-launching is always better than that involving the insurance companies and the work shop. The issue is people, as some have mentioned below you usually get away with it, one day you will not.
Totally agree. You‘ll also find several videos on rope break exercices where the pilot grabs twice for the release handle as it starts to move at 0g and he misses it the first time. In case of an execice that‘s no problem. If the cable breaks some feet below you, the rope might snap up if not released quickly. And if you drop a wing in a winch launch, you have even less time to react than in aerotow.
I saw your theory on prop wash. I was thinking about that earlier in the video, are there often many issues relating to prop wash? Is there a technique to avoid the affects?
YES..Tow plane holds brakes while spooling up..
Third example: the wing man was really lazy, but I feel that in this case, the pilot possibly should nor have released, because the tow line would pull the glider towards the center (nose hook). Also, when the line was released, the aileron was neutral for about 2 seconds (when you release, you loose control of other things...). It really looked like the glider was recoverable, if it were not for the loss of roll control for 2 seconds... i wonder did he had his hand on the release, or started fumbling around and lost controll of the roll when he tried to grab the release?
As someone that has flown from that runway I can confirm that is not the case. I had something similar happen to me with a crosswind and was further down the strip (not near the fence) and I couldn't get the tip off the ground in an ASK21. Probably something do with the terrain and structures around that end of the airfield. The club has a lot of older members so I don't think laziness has anything to do with it.
"Hm, everything looks perfect but the grass is a bit too high. Still, so much time and money spent on getting here, so...."
Ai 5:45 the pilot coud have kicked the right rudder to correct the situation.
Had a tip drop on me when I was the front glider of a dual tow. Not fun.
Nasty! I would guess it's more likely for a wing drop due to the offset positions of the two gliders...
@PureGlide yes. It was particularly nasty since we didn't brief this kind of thing. I managed to pick up the wing, but I was happy to have a nose hook and tail wheel.
Tim! The wing drop dur to prop wash is not a theory. It is a well-known fact (at least in Poland). We learn this during our basic aerotow training and it is well described in books published 50(!) years ago. Please spread the word as I find it very important for safe aerotow launch. The wind direction is` the first thing I check before aerotow launch and I even apply some counter-aileron correction before take-off.
#3: Wing walker or wing runner?
Did #3 wing runner push the wing away from him???
It looks as if some crude use of the rudder (rudder deflection) to help keep the glider on track, caused as a secondary effect, roll to the left, causing the port-wing to drop and catch in the grass (first incident)
Tim, we both fly the Ventus cT and use negative flap at the start of the ground run - just when there’s the risk of wing drop. How do you manage, without having two left hands?
I recognise la Iglesuela airfield in the 1º clip.
Question: having been trained to do a wing down launch, this seems to be at odds with the advice to abort if the wing drops… I’d appreciate any advice here.
Yeah that is a useful skill to be able to do, sometimes it's the only option. But conditions have to be good to do it, e.g. 15m glider, short grass etc. Good prop wash over the wings helps get control early. Or a good head wind. I never do them with my 18m wingspan... I'm pretty sure I've had to bung off attempting a couple too... so I'd consider it an advanced thing to do. And don't do it near the fence!
@@PureGlide Thanks heaps - a useful caution to be aware of and I’ll definitely be wary of cross wind conditions 👍
I've heard that gliders aero towing with GC hooks are more prone to losing directional control on the initial ground roll. Any truth to this ?
I have a release extension,so that the release is on my lap. With full stick deflection to the left, it is impossible to grab the release otherwise.
Adding to that, I am flying a flapped glider, so my left hand is on the flap lever until airborne.
Yes absolutely, because a nose hook is actively pulling the glider into alignment, while a belly hook requires to be flown in the right direction. It won’t auto correct itself if you start going off on an angle
Hand ON the release regardless of launch method. Get into the habit of always doing out
I have a question. Have been thinking whether to join a gliding club. I don't have flying experience, but have spent time learning essential theory. But, to my question ... I've noticed there is fair bit of "banter" in aviation. Having watched the TV aircraft accident programs, I estimate one-third have psychology as a factor, where someone in the cockpit was intimidated by rank seniority and not performing to task.
Don't get me wrong -- I'm not complaining to avoid critique. I'm asking whether the critique is chronic.
Well, I am pondering whether microlights might provide an option less prone to human performance pressure, put it that way.
Ok, so with a crosswind takeoff you can have differential lift which forces one wing up and the opposite wing down. So, should that affect choice of which wing your wing-runner is operating from?
When I was instructing the thing we used to consider was that a crosswind was likely to make the glider weathercock at low speed. The wing-holder could counteract this by slightly holding back on the wing at the beginning of the take-off run. But you need to take into account all sorts of variables, including the power of the tug and the size and weight of the glider, and different considerations might apply with a winch launch. And of course an experienced ground crew could predict which wing might be likely to drop and counteract that by keeping one wing higher than the other. Good ground crew are very valuable. But I flew at a massive airfield with very wide runways. It was a very forgiving environment, but you get complacent at your peril.
@@martinboycott-brown1994 Thanks for the reply.
Hold the release for all launches, there’s no excuse.
Why does air break reduce wing drop?
The theory goes that it spills the air outboard over the ailerons, increasing their effectiveness. Or, the drag and on some types wheel brake means you delay the start of the ground roll a little bit and so the wing runner is still holding your wing until the tug is developing full power. Personally, as an instructor and tug pilot, I don't like it, and think that your hand should be on the release and not on the airbrake.
Sounds about right. To be fair those who use it only don’t for the first part of the ground roll. But yes that would slow down release time possibly
@@BruceDuncan Thank you.
Some pilots are also too lazy to fly the aircraft while stationary on the ground. As a wing runner you then have to give to much force to keep it level. Then when letting it go the wing drops. Surprise? NO. As a wing runner you should apply minimal force, and let the pilot do its job. But some pilot just don't get it that they need to do stuff even when stationary just for take-off.
Hi. Im the pilot!!!
If do you have some question, its a honor for me. Thank you!!
Hello! I thought you handled the ground loop very well. Thank you for sharing the video, it's a great lesson for people how quickly it can happen. I added a link in the description to your original video. Cheers
and the fact that it has one wheel in front has nothing to do with it?
What does? The gliders that have one wheel in front are probably MORE stable at low speeds because of it. Or do you mean because we only have one main wheel? I don't think that's very different from a taildragger, if at all.
7:03 You should never have your hand on the release on a winch launch because you could accidentaly pull it. In Germany they teach use to have it really close to the realease but never on it
Dont you mean always have your hand on the release during a winch launch? Accidental release is recoverable at all stages if flown correctly. Any delay in releasing is likely to result in crash if catching a wing tip as it will enter an uncontrollable cartwheel.
@@david3599 it doesnt take long to pull the release its almost as fast as if your hand is on it because its right next to it so there is almost no delay you just have to be ready and prepared. The problem wit accidental release is that if you fly it right its recoverable but its always a high risk. Humans make mistakes so maybe u messed up the launch and pitched up to steep and then released or you make a mistake after the rope releases and crash then. So i think having the hand really close to the release makes it so you can still release quickly but you also avoid the risk that would come with a accidental release
I might make a video about this, and almost did cover it in this video. I argue hand should always be ON release with a winch launch. Any delay could be fatal or catastrophic with a cartwheel as it happens so fast. Releasing accidentally is very unlikely to be fatal, especially while bumping along the ground at the start. Also it could happen anytime with a rope break.
@@PureGlide If your hand is near the Rope release it almost doesnt delay it. Releasing accidental is like a ropebreak but ropebreaks can be very dangerous even if trained so thats not good. I know its pretty unlikely to happen but in my club it already happened. I think the risk is higher if the rope release isnt a ball but has a T shape
If you search for British Gliding Association safe winch launching they clearly state on the website:
Start the launch with your hand on the release. Why hand on the release? Because you need to pull the release within half a second of taking the decision to release. Why immediately? Because the cartwheel that may follow a wing drop onto the ground can be so rapid that no recovery by releasing or other means is possible.
If you have alternative official information, please do share the source.