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Old Jul 11, 2002, 04:59 PM
Registered User
San jose, CA
Joined Jun 2000
426 Posts
Using a winch: how do you know when to release?

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
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Old Jul 11, 2002, 07:13 PM
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Ranfred Radius's Avatar
Central Point, OR.
Joined May 2002
2,926 Posts
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
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Old Jul 11, 2002, 07:35 PM
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United States, FL, Starke
Joined Apr 2002
2,259 Posts
Re: Using a winch: how do you know when to release?

Quote:
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!

What plane are flying off that winch?

dd.
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Old Jul 11, 2002, 08:16 PM
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Punta Gorda, FL
Joined Apr 2002
4,952 Posts
Winch Launch

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.
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Old Jul 11, 2002, 09:22 PM
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Keremeos, BC, Canada
Joined Dec 1996
632 Posts
Winch use

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...
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Old Jul 11, 2002, 09:53 PM
aka: Dances with Buzzards
ICTHRMLS's Avatar
TX
Joined Jun 2002
454 Posts
Re: Winch use

Quote:
Originally posted by Terry Lyttle
You want to really punish your launching skills, try hand tow, that separates the pilots from the punters...
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"
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Old Jul 11, 2002, 10:30 PM
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R. Carver's Avatar
Oviedo,FL
Joined Dec 2000
1,164 Posts
Re: Winch use

Quote:
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 I'm not the best launcher, but I do alright
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Old Jul 12, 2002, 03:37 AM
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San jose, CA
Joined Jun 2000
426 Posts
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
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Old Jul 12, 2002, 09:31 AM
Not Really
Fast-Forward's Avatar
Natick, MA
Joined Nov 2001
707 Posts
Re: Re: Winch use

Quote:
Originally posted by R. Carver


I hate hi-starts too I'm not the best launcher, but I do alright
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...
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Old Jul 12, 2002, 10:01 AM
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R. Carver's Avatar
Oviedo,FL
Joined Dec 2000
1,164 Posts
Re: Re: Re: Winch use

Quote:
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
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!
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Old Jul 13, 2002, 04:48 AM
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San jose, CA
Joined Jun 2000
426 Posts
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
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Old Jul 13, 2002, 08:53 PM
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Keremeos, BC, Canada
Joined Dec 1996
632 Posts
Winch... histart...

... 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...
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Old Jul 14, 2002, 01:39 PM
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fprintf's Avatar
Cheshire, CT, USA
Joined Jan 2001
1,528 Posts
Histart vs. winch - I finally got to try... wow!

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.
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Old Jul 14, 2002, 08:44 PM
Registered User
Columbus, Ohio
Joined Jun 2002
303 Posts
Blew up a wing today...

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
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Old Jul 14, 2002, 10:10 PM
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Punta Gorda, FL
Joined Apr 2002
4,952 Posts
Carbon Wing Joiners

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.
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