Using a winch: how do you know when to release?

[tempest411]

I finally taught myself how to use the winch kept out at the club field and as it turns out, it's actually pretty easy. I was really worried about standing on it for too long and blowing up my plane or something, but as it is, this winch must be pretty mild because I can just keep it on all the way up without a problem. The one thing I've already noticed that can really make a difference is when and how you release. Because the amount of pull is relatively constant, the plane seems to go up in a nice round arc. But knowing when you are right at the very top of this arc is kind of difficult to see because of the angle the plane is at relative to where the pilot is, so sometimes I come off the line when the plane isn't done climbing. Other times, if I release at just the right time, and pull up, I can get a LOT more altitude. Any advice on how to do the latter with consistency?

Either way, this method of launching has it all over a hi start!

Rick

[rocketman47]

Rick,
Stay on it until the sailplane starts to get pulled down. Dive it(stay on the peddle) Let off on the "gas" as soon as the glider releases, pull hard back on the elevator. You'll gain a considerable amount of additional altitude. This is whats known as a "zoom launch".

Randy

[Doc Data]

Originally posted by tempest411
Other times, if I release at just the right time, and pull up, I can get a LOT more altitude. Any advice on how to do the latter with consistency?


PRACTICE! :D

What plane are flying off that winch?

dd.

[Ollie]

The best winching technique depends on a number of things. The first 2/3 to 3/4 of the launch should be done with the minimum speed to keep the plane climbing reliably so as to use up the minimum line length. If the plane's wings can take it, the last part of the launch is done with the pedal held down to build up as much speed as possible. Timing the pedal down acceleration depends on the winch power, wind speed, wing loading, etc. Just before release the trailing edge of a full house sailplane should be reflexed a bit to reduce profile drag in the climb. The speed should peak at the apex of the launch and the release is under maximum line tension (ping). After release the maximum altitude can be gained by going vertical and rounding off as the plane slows to the hands off glide speed as the trailing edge reflex is switched off. In a vertical climb the wing produces no induced drag and the plane's kenetic energy is converted most efficiently into the potential energy of altitude. A good zoom launch is a fairly complex maneuver that takes a lot of pilot skill and practise with the model under varying conditions.

[Terry Lyttle]

Who said practice??? There IS no substitute for practice: the foot gets wiser (particularly after a few busted models), the eye gets sharper, the model is retrimmed again and again for maximum performance. If you figure on mastering a good launch (never mind a good zoom launch) in a few weeks, forget that. The fact that you seem contemptuous of histarts makes me think that maybe you are short on... um, practice.

You want to really punish your launching skills, try hand tow, that separates the pilots from the punters...:D

[ICTHRMLS]

Originally posted by Terry Lyttle
You want to really punish your launching skills, try hand tow, that separates the pilots from the punters...:D

OUCH!!! Nothing worse than being the tow guy for someone learning how to hand tow launch - you burn up an awful lot of shoe leather when they don't "give it up" ;)

[R. Carver]

Originally posted by Terry Lyttle
The fact that you seem contemptuous of histarts makes me think that maybe you are short on... um, practice.


I hate hi-starts too :p I'm not the best launcher, but I do alright :D

[tempest411]

I don't like high starts for the simple reason that you don't get as high as easily with them compared to a winch. Even on my bad launches, I was still going out a lot higher than with my high start. I've been using Hobby Lobby's 3-4 meter high start for my launches up until now. But most of all, I love all that extra energy at the top of the launch! I've always had the feeling that if I could just get a little higher, I'd have a better chance of catching more concentrated thermal lift. And on my first attempt, this was born out when I put the Milan(a plane I've not been in love with, and wouldn't feel bad about if I blew it up) I was using into a thermal and up it went.

Doc Data,

Besides the MPX Milan, I have an Amethyst, and a DCU/Airtronics Legend. I only launched the Amethyst once before deciding I'd had enough of the 105 degree heat in the middle of the day, but it flew much, much better than the Milan.

Rick

[Fast-Forward]

Originally posted by R. Carver


I hate hi-starts too :p I'm not the best launcher, but I do alright :D

I don't understand why there is so much Hi-start bashing going on. I started out using a hi-start. In fact, I purchased 50 ft of 3/16 id x 3/32 od surgical tubing for $13.00. Then I purchased 450 ft of 50 lb ice fishing cord for $4.50. Finally I purchased a clevis pin for $1.25 and some radiator clamps to top it all off. I used an 18" fiberglass tent pole for the anchor and a key ring as the tow hook. Once assembled, I have 50 ft of tubing with 75 ft of cord with the key ring on the end. So, all totaled up, I have spent less than $20.00 for a highly portable, quick to setup hi-start.

Of course this doesn't launch me as hi as a winch but, who cares. I can go flying every day after work at my favorite field and I don't have to carry a winch around to do it.

Besides, winches aren't cheap. They are in the hundreds of dollars. So when it comes to flying, If you really love it, you will do what it takes to get in the air and get some practice. Don't be a winch snob! ZZZoooooomm...

[R. Carver]

Originally posted by Fast-Forward

Of course this doesn't launch me as hi as a winch but, who cares. I can go flying every day after work at my favorite field and I don't have to carry a winch around to do it.

Besides, winches aren't cheap. They are in the hundreds of dollars. So when it comes to flying, If you really love it, you will do what it takes to get in the air and get some practice. Don't be a winch snob! ZZZoooooomm...

I started with a hi-start, too. Flew off of one for about 8 years.
My winches are pretty cheap. Got 6 of 'em. The field (which has a storage shed with power) is 10 minutes from my house, so transportation isn't a hassle. No club dues for officers, so all this is pretty much free for me :D
Seriously, if I wasn't in this position, with no club nearby, I'd probably be flying off a hi-start too. Like you said, whatever it takes to get you in the air. I'd probably stick with 2-meter though (no comments, Dave ;) )
I've said it once and I'll say it again, if you've never seen a good winch launch, you owe it to yourself to make the drive to a club to see one!

[tempest411]

Ditto for me as well. I have been off my high starts for seven years, and I paid in total about $130.00 for the two that I have. But the winch I will be using belongs to the club, and also stays at the field...in a shed that has power going to it. There's always four marine batteries there, and two of them are always kept on chargers, so they're always ready to go. They even have little wagons there to help move the wiches, batteries, and turn arounds out to the flight line. I think I'm very fortunate to have this available to me, and I'm very greatful.

Rick

[Terry Lyttle]

... either or. I have a theory that if the lift is there, it's there. One of our guys used to handlaunch his big (120"+) V-tail into lift on a flat field. His trick was, um, practice; not launch, but reading thermals.

We flew at the w/cs in '81, east of Sacramento, and sometimes it didn't matter how good the winch OR the launch (we had the best of both, just not all the time), the model would be on the ground shortly after the chute.

If you want long flights, go sloping; find a place where the lift is constant, and knock yourself out. Just remember, there is no cure for sunburned tonsils...

[fprintf]

Well, to add my 2 cents, I was strictly a high start guy, as I had no access to a club with a winch. A guy I fly with has two winches and we recently took a trip to a sod farm. I only flew one flight off the winch since he was practicing his F3b laps, but that one flight was wonderfully high.

I have found that with any wind over 5-10 mph my hobby lobby 3-4M 100 ft. histart with 80 yards of 50 lb mono gets my highlander several hundred feet (300?) in the air where I can potentially catch a thermal. When the wind dies I get *at most* 200 feet of altitude. The winch got me to 500 feet without any wind and only tapping on the pedal. My friend tells me I can move my tow hook back 1/8" or more to get a better launch.

[Chipwillis]

I blew up a wing on a contest ship today.

Failue- Carbon wing rod.

Cause- number of things I think. One is I knew my towhook was too far forward and should have moved it last night, but I was wiped out after contest Saturday.

The second thing was, I had a pop off in the first round, from trying to pull too much up to get the wing going up at a steeper angle. No biggie- I knew exactly why, and should have been content with somewhat flatter launches.

Next launch- kept the aircraft going up and up and decided, if I couldnt get the high, then try and zoom more. Problem with that was, I went out too far ( past turnaround, and stood on the pedal while diving, and when off the pedal pulling up, the wing blew up on me.

Everyone at the field said they never trusted CF rods, because they offer no hint of impending failure.

So, lessons learned where, If I build that same aircraft and can get a Aluminum or Steel wing rod. give up some weight.

Second was try and be in the dive before reaching the turnaround.

Dont be lazy and fine tune the towhook position before a contest!

And, lastly, when in doubt, dont zoom. I had asked someone if they thought my spar was strong enough, and was told, probably, but dont zoom it too hard. Two strong hints to take it easy, and I didnt listen to them. Guess they are good lessons to learn.

All in all I saw two complete wing failures today, and one damaged. The other two were poly ships and really not applicable to me, but again, gentle taps have their place.

I can remember a time when winching a unmodified sophisticated lady..... It can be done, just be careful.

So Ill be the guy afraid to zoom for a while....

Chip

[Ollie]

Chipwillis,

There is nothing wrong with a carbon wing rod if it is sized to allow a safety factor over the worst case conditions. Carbon is brittle and doesn't fail gracefully like metal rods. This just means that carbon has to be about 25 or 30% larger in diameter than a properly sized steel rod in order for the carbon rod to stand up to a hard zoom. Another necessity is that the inside ends of the joiner tubes have to be deburred and flaired a little so they won't cause stress concentrations in the carbon rod. The majority of high performance contest models use carbon wing joiners without problems.

BTW, in a deep dive the plane can out run the winch line. This is risky not only from the speed build up but the line may foul the tail with disasterous results. The best zooms employ little or no dive and the plane comes off the line with a "ping" because the line is under very high tension.

[NickW]

As to the question of when to release? When you stand on the pedal at the top for the zoom and the wingtips are about to touch, then you release ! :D :D :D

Seriously though... Its all about practice and timing, and its not something you will pick up instantly. If you ever fly with other fliers take some time to stand to the side of the winch launches and listen to the pedal tapping, watch the airplanes, and watch where the chute falls back to. Some guys wind in WAYYYYY too much line doing full pedal launches. Theres an art to winch launching, and it pays to watch others and learn from their methods. The guys that draw in the least amount of line, and zoom to the highest altitudes are the ones to watch. A high zoom that pulled in too much line is not better than a shorter zoom from a guy that tapped his way up the line but ended up higher than the heavy tapper. I hope that made sense...

practice, practice, practice. And stop tapping at the first sign of wing flex! Be careful!

Nick Wisdom
Providence, RI

[denete]

<wise@$$ on>

Try to release somewhere before the plane goes through the turnaround.

And for the person who wanted to know how long they could fly on a 600 mAh battery. I'd say, until the plane stops responding.

<wise@$$ off>

- David "kick me" Enete

[Terry Lyttle]

... is good. :D Although I have seen guys amazingly close on release, usually due to backwind on launch; this is not possible with histart. I mentioned practice, and we used to have some thermals that would pop in unusual places, immediately generating cross, or back, winds. I have had my Olyll going up the histart 90 deg from launch line, clearly in lift (the rubber was double its length , looking at triple!). Remember what I said about elevator authority and hook placement? can you say ping launch? Wow.

All has to do with practice (there it is again). I have seen guys fly lots of models poorly, some other guys fly mediocre planes well due to... oh, well, you know...

[Ollie]

The following web site has an actual altitude versus time measurement of an F3B zoom launch showing an altitude gain of 300 feet on the zoom! See:
http://www11.brinkster.com/f3bseries/lolo_02_3.html

[Terry Lyttle]

... we were there; they rewrote the rule book to dump out the horsepower part, but it took this long to catch on to the Baseball Theory, ie, the pitcher doesn't have to be doing 100 mph to throw a fastball. It is ALL in the launch profile, be a baseball, or a sailplane. Not too much new here, except the refinement of the Canadian launch tecnique from 1981; Brian will be proud...

[aeajr]

Winch launching is a new challenge for me.

I have a two meter Spirit. I have two hi-starts:

25' 7/16 tubing and 150' of line that I use for practice - Puts the plane up great. Have launched 3 meter birds off of this

100' 1/2" tubing and 400' line - This will also launch a 3+ meter plane. My Spirit gets launches that rival the winch launches. I often launch off the hi-start right next to the winch guys.

I tried winch launching 3 weeks ago. Two wobbly launches but i got the plane in the air. Third launch was a disaster. Spirit has been on the bench ever since.

Personally I find hi-start launches fun and I dont' feel I give up much to the winch. However I will master the winch, once I get the plane back in the air.

[RCFlybry]

The winch got me to 500 feet without any wind and only tapping on the pedal.
Not bad.. Not bad at all! Now you need to come flying with us next summer. We have a dry lake bed out here that's huge. We have 2400 feet of line on our winch drum which allows 1200 feet from winch to turnaround. Overkill for sure but a lot of fun! Gentle launches will still get you to 750 or 800 feet. On the other hand, high launches won't make you better in finding thermals, so I can't fault anyone for using a high start. I think the thing that I like about winch launches most is the fact that you have more control over the launch. If something goes wrong.. get off the pedal and fly off the line. Something you can't do with a high start.

Bryan

[aeajr]

I have heard this arguement about winch vs hi-start. With the winch you have more control. However I have seen more accidents and crashes off the winch than I can count. Frankly I have never seen a crash off a hi-start. That is not to say they don't happen.

I have seen pop-offs from winch and hi-start with similar results.


For me, the hi-start is easier for several reasons.

Once I pull the hi-start the tension is constant. With the winch, I have to pick up the slack, and if I decide not to go, I get off the pedal and the line goes slack again. So I have to time when I throw with the state of the line.

Wiht the hi-start, once I throw the plane and it is going I only have to concern myself with the plane, not the pedal. Doing two different things at once is not simple. It is like the old rub the tummy while you pat the head.

So it is steer the plane while you tap the pedal.

Of course if you did crash off the hi-start, the tubing would continue to pull the plane on the ground making things worse, though I have never seen it happen. The winch you can release. Granted.

I am sure I will get used to the winch, but for now, it is a challenge.

[RCFlybry]

aeajr, I agree with you that the highstart is a simpler method.
Especially if you spend a lot of time flying by yourself. It's much easier to fly up the line without having the added task of tapping the pedal. We've somewhat simplified the winch a bit though.
I hold the plane overhead and have my flying buddy on the pedal. We each take turns tapping each others plane up the line.
He's actually gotten good enough to where he can do it by himself. I still need more practice doing it alone. We've gotten to where we're pretty much in tune with each other and haven't had any problems doing a two man launch yet. When I fly by myself though.. It's the highstart that comes with me to the field. If your winch launching by yourself.. Hat's off to you, as your one step ahead of me. ;)

Bryan

[aeajr]

That is a good suggestion. One fly and one work the pedal. That may be what I need to do till I get the hang of it.

Thanks for the tip. This may be the best way to learn to moderate the winch.

[Ollie]

Flying the plane and pulsing the winch is kind of like patting your heqd and rubbing your belly at the same time.

Performance improves with practise. The task has to be so automatic that you don't have to think about the deatils of what you are doing. This comes only with practise. Until then, thinking about one of the tasks affects the performance of the other.

Here is a practise exercise in controlling the winch that does not endanger a plane:

Hold the launching ring in your hand so that if it is pulled out of your hand it won't take any flesh with it or jerk you off your feet. Then tap the pedal so lightly that the winch doesn't even run. While maintaining the rhythm of the tap, gradually increase the strength of the taps until the briefist contact is made and the winch starts to pull. Keep the taps as short and light as you can. Vary the rhythm to control the pull on the line. Slow rhythm for less pull and faster rhythm for stronger pull. You can also modulate the pull on the line by varying the pules length but, the pull is not as even with pulse duration modulation as with frequency modulation. Practise until you can maintain a constant pull without having to release the ring. Then practise some more until you can maintain the constant pull while holding a conversation with someone else. Then practise some more until you can do it while working math problems in your head or any other mental exercise that requires your full concentration.

[aeajr]

Ollie,

This is brilliant. Whenever I need to know something, I should probably just search on your name.

Between this excercise and the one provided earlier I think I will be able to master the winch much more quickly.

Now I just have to get the plane off the repair bench.

[Ollie]

Learnig a physical skill like pulsing a winch, driving a car, flying a plane, swinging a baseball bat or golf club requires paractise because your higher mental processes involve a time lag of at least 0.4 seconds and that delay spoils the execution. Physical slills like that require faster and more automatic reactions that bypass high level mentation.

In other words, your body speaks a different language than your mind. Your body processes information in terms of kenesthetics (feel) and your mind processes information in terms of words, images, sounds and concepts. Kenesthetics is only a minor sense among many other (major) senses.

aeajr,
I didn't live 72 years wihout learning a few things along the way. Investing in your own knowledge and skill development enriches your life with things that can't be so easily lost, tossed in the garbage or stolen. Sharing so many of those things with the next generation is something that sets us apart from the rest of the animals.

[John Walter]

An interesting discussion of histart vs. winch. For years I used only a histart. Then a year ago I bought a used Graupner winch loaded with mono. It has a ratchet anti-reverse rather than the more typical V-belt brake. Not a Ford long shaft, but it works well.

I simply engage the anti-reverse, and pulse the winch to build some tension in the mono (much like a histart). I then give the plane a good heave (again like a histart) then pulse the pedal during launch. I find that a mono line is much easier than braided line.

Over the past year I have learned to use a winch reasonably well. Given that I fly woodies, I don't try to zoom like an Icon, but I get pretty good launches. I've tried zooming my Grand Esprit built with a CF spar, but airfoil has such high drag a high speed that it does work very well.

I still use an Aerofoam 2M comp histart for my 11 year old son's Chrysalis 2M. That way, once I throw the plane he can launch on his own without the added task of pulsing the winch. BTW, Aerofoam histarts are amazing! I get 400+ feet in calm conditions.

[fprintf]

I think I need an Aerofoam histart. I have the fat Hobby Lobby Red and I only get 400+ feet with a 5+ mph headwind with 60 steps of stretch (perhaps 180 feet on 100 feet of tubing - my arm can't pull it any more).

[aeajr]

Line + tubing length plus applied energy is the primary determining factor on how high you can launch with a hi-start or a winch.

A max launch would occur if you could get the plane directly over the spike/turn around pulley at the end of the launch. It is very rare that someone gets that straight up, but let's say you could. That would be your max launch.

The winch has two advantages. First it doesn't need stretch room. If your field is 700' wide, you can put out about 700' of winch line, hit the turn around and come back, max height on a perfect launch will be 700' minus whatever you reel in. If you pull in 150' of line, then your max launch would be around 550' + zoom at the end. On a windy day a skilled winch launcher knows to pull in less line and let the plane kite up. Then he pegs the pedal near the end to give that speed for the zoom off then end. He might get a 600' launch that way plus a 150' climb from the zoom at the end. Impressive!

The second advantage would be that the winch has the same power at the end of the launch that it has at the start. The hi-start gradually loses power as it contracts so you have less opportunity to zoom at the end off the hi-start, and you can't control it. You power the zoom with whatever stretch is left, or from the weight of the hi-start pulling the plane down. You can't punch the pedal like you can off the winch.

So what is the best launch your hi-star could provide?

Fprintf, I looked at the hobby-lobby site on hi-starts. Which of these hi-starts do you have?

http://www.hobby-lobby.com/histart.htm

It looks like Hobby Lobby's longest hi-start is about 400' meaning 100' latex tubing and 300' line. The RED tubing you reference seems to be 3/16 ID and 5/16 OD. I have used my friends 5/16" hi-start. It has 300' of line, like yours. He wanted a higher launch, so we made up add-on line in 50' lengths that we add using snap/swivels.

In calm air, my 2 meter Spirit can't quite carry up the 300' line plus tubing regardless of how far I pull it and I get a weak zoom at the end. Let's say I hits 325 feet.

In a 7 mph wind, I can climb higher due to the kiting effect and get a better zoom because the wind helps to slow the contraction of the rubber, again due to the kiting effect, giving me more zoom at the end. I might hit 425' We found we could add 50 feet of additional line under these conditions giving that much higher launch.

My hi-start is 500' long which includes 100' of very strong half inch tubing and 400' of line that I use to launch my 2 meter Spirit. Due to the stronger rubber I get a more powerful launch with half the pull, compared to my friends hi-start. In calm air with a strong pull my two meter Spirit, with a moderate zoom, might hit 400'. With that same 7 mph wind to help, and the zoom at the end, I am sure I break 500' On a windy day I could probably add another 100' of line and still have room to get the needed pull. He is out of space.

Net Net, if you want a higher launch you can go to a winch. However but there is plenty you can do with the hi-start to improve your launches.

First, you can experiment with adding more line based on wind conditions. Make up 25-50 foot lengths with snap swivels that you can easily snap onto your hi-start. Give it a try.

Second, you change to stronger hi-start rubber so you get more power in the same space. You might be very surprised at how high you can get that plane without the expense of a winch.

The winch will always have the advantage, especially in cold weather when the rubber becomes stiff. But in moderate to warm conditions, you can close the gap quite a bit.

I hope what I have written here makes sense.

[rdeis]

Originally posted by Ollie
Here is a practise exercise in controlling the winch that does not endanger a plane:Hold the launching ring in your hand so that if it is pulled out of your hand it won't take any flesh with it or jerk you off your feet. Then tap the pedal so lightly that the winch doesn't even run. <etc, practising maintaining various levels of tension.>

I'd forgotten all about that, but now that you've said it, I remember that it's precisely how I learned. Once I could consistently maintain the same level of tention that I felt on a fully streatched high-start I became comfortable with my launches in relatively short order.

(Before that I flew and someone else threw it and worked the pedal- the two man method is great for learning to fly the line!)

[aeajr]

Originally posted by Ollie
Here is a practise exercise in controlling the winch that does not endanger a plane:

Hold the launching ring in your hand so that if it is pulled out of your hand it won't take any flesh with it or jerk you off your feet. Then tap the pedal so lightly that the winch doesn't even run. While maintaining the rhythm of the tap, gradually increase the strength of the taps until the briefist contact is made and the winch starts to pull. Keep the taps as short and light as you can. Vary the rhythm to control the pull on the line. Slow rhythm for less pull and faster rhythm for stronger pull. You can also modulate the pull on the line by varying the pules length but, the pull is not as even with pulse duration modulation as with frequency modulation. Practise until you can maintain a constant pull without having to release the ring. Then practise some more until you can maintain the constant pull while holding a conversation with someone else. Then practise some more until you can do it while working math problems in your head or any other mental exercise that requires your full concentration.


The snow is pretty deep right now, but I am still thinking about that nasty winch. My Spirit should be flyable again by Christmas. I have added a Sagitta 600 to the hanger as well.

I have been thinking about your advice that I quote above. I am definately going to do this. I have gone one step further and would like your opinoin. I have not actually tried this yet.

I purchased a fish scale that goes up to 50 pounds. I plan to set up the winch when there is no one else at the field. Then I will attach the fish scale to the line and try to tap the pedal to a constant 10 pound pull.

With the scale I can gague whether I have an appropriate pull and whether I am really maintaining it.

I also plan to hi-start my plane. I have never measured the pull I have been using on the hi-start. Once I know, then I can try that pull on the winch. I am certain it is more than 10 pounds. It might be closer to 20.

I will let you know how it goes. The snow has to melt first.

[Ollie]

Aeagr,

I like your approach.

Soon you will want to design and build wing spars that will break the winch line before the wing folds (even if the solenoid sticks and foot pedal control is lost).

At the rate you are progressing I think you will be one of your club's Gurus before long.

[aeajr]

Ollie,

It is with your help, the help of the people in our club, and others on these boards, that I am progressing. No one does it alone.

We have planes in our club that break the winch lines on zoom launches. When we hosted the last ESL event, I believe they had about a dozen winch line breaks.

As for progress, I have committed to this hobby big time. I will drive for competence across multiple areas. If I achieve competence, then I will seek to achieve excellence in a select few, but not before.

Right now I feel I have acheived competence on hi-starts. Now I must master the winch.

Your advice will be critical to that achievement.

[ArnoldC]

What I have been doing is when the airplane reaches the highest altitude on the winch, push the nose down (holding the gas to the grass) and pull up, however be careful doing this, it is very hard on the airplane, and DO NOT PULL UP TO FAST, OR PUSH THE NOSE STRAIGHT DOWN, you do that you will have a kite on your hands! but honestly there is no need to drag the line way the heck out in the boonies it doesnt do you or the airplane any good. If your airplane "levels out" or even starts to loose altitude time to get off.

Happy Thermals
Arnold