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Jul 25, 2002, 03:36 AM
Registered User
Thread OP

Learned an $800.00 lesson on the winch today...


Hey everyone,

I taught myself to use the club's winch a couple weeks ago and had great success, but at the time I didn't quite see how the retriever worked so I did without it. Today I took a closer look at it and figured it out...great convenience in not having to go out hunting for where the line dropped in the weeds, but it seemed to sap a noticable amount of energy from the climb. On my tenth or so launch though, the retriever line wipped up and over the V-tail of my Amethyst, causing it to pitch up...I let go of the winch immediately, leaving me with about 70 ounces of carbon and kevlar just hanging in mid air, with the nose pointed straight up! I knew my only chance was to let it dive and hope I can get enough airspeed to get it flying again, and hope I can fly myself out of the entanglement...but, oh, I wasn't able to do that with the little altitude I had. It went straight in, and is a total loss. In hindsight, even if I had got it flying again, it would've been of little use. Once on the ground, I could see that the retreiver line had actually jammed itself between the control surface and the ruddervator, freezing at least one side of the V-tail. The other thing that ocurred to me was that I could have prevented the whole incident altogether by attaching the retriever line to the steel ring that was about 5-6' away from the end of the winch line, instead of the end itself where I had assumed it was supposed to go. This would have kept the retriever line well clear of the plane on launch.

The moral of the story is of course to have an experienced pilot teach you how to use this stuff(duh!). But as I work weekends, the field is just about always vacant when I'm there, so I have to learn all this stuff on my own. Funny though, when I totalled a $50.00 Bridi EZ-100 teaching myself how to fly, it hurt a lot more than what I did earlier this morning. I think it's the time you put into it that means the most when the fruits of your labor hit the dust. But boy, that Amethyst was a great flying plane...

Rick
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Jul 25, 2002, 04:30 AM
Registered User

Retreiver Line Attachment


The best retreiver line attachment involves three rings and two ball bearing swivels. One ring is at the end of the launch line as usual. The second is tied to the launch line about five or six feet down the line. The third ring is around the launch line between the first two rings and free to slide along the launch line but, sized small enough not to be able to go past either of the first two rings. The two swivels are connected back to back. The ball bearing housings of the swivels have a pointed end and a flat end. When assembling the swivels it is important to have the pointed ends pointing in opposite directions. One end of the swivel assembly connects to the sliding ring and the other end to the retreiver line.

During launch the retreiver line pulls the sliding ring away from the model. During retreive, the retreiver line pulls the sliding ring to the end of the launch line. The back to back swivels prevent twisting of the retreiver line much better than a single swivel.
Jul 25, 2002, 08:32 PM
Registered User
John Gallagher's Avatar
I've never seen anyone use a retriever without a second man to watch and operate it. Is it common practice at other clubs?
Jul 25, 2002, 08:47 PM

Lemme see...


...retriever...retriever... Isn't that what teenagers are for? That's all we ever used: you can usually find one teen that is interested enough in the hobby to chase lines/chutes in exchange for a few flights. I must admit that none of my models would come near the $800 price, but once in the air, even a neophyte can fly 3 mistakes high. I've seen lots of retrievers, and still go back to an interested teen.
Jul 25, 2002, 09:35 PM
You mean you can use the line more than once? Spelchkr
Jul 26, 2002, 05:19 AM
Registered User
Thread OP
Ollie,

There was a sliding ring of some sort between the two other rings, and some concoction of links at the end of the winch line, so the assembly as you described is probably already there, I just had no idea how it went together. Another issus I was thinking about is the amount of power that was used up by the retriever line. I wonder if there wouldn't be something to gain by using that light-weight fishing chord(not the transparent stuff) instead of the generic nylon twine that is on there presently. The nylon twine makes a good thumping sound as it whips the retriever base as it comes off the spool, I don't think the lighter fishing line would do that.

Another thought that occured to me in retrospect was that I remember assembling my Amethyst and thinking 'maybe I should use the Milan just to test the waters with this retriever thing...', and then dismissing my own fears! Now my only really nice flying thermal plane I have is my Legend, but it doesn't have the speed envelope of the Amethyst. I just saw they're on sale at NSP for $599, $160 less than I had paid just three months ago...mmm, I'm tempted...

"I've never seen anyone use a retriever without a second man to watch and operate it. Is it common practice at other clubs?" I've been a member of the SBSS since 96' or 97', and I've only seen another person or two at the club field on maybe five occasions. For the most part, I rather like that as I enjoy the solitude, but I am at a disadvantage when it comes to the learning curve, which for me looks like this:__________________

Rick
Jul 26, 2002, 07:12 AM
Registered User

Launchiung Technique


Flying alone isn't a particularly good idea for several reasons but, you will have to be the judge of that.

Avoiding entanglement in the retriever or launch line involves the right rigging of the retriever line, keeping some tension on the retriever line during launch and releasing while there is some tension on the launch line. Most retrievers require an experienced operator in addition to the flier.

If you do fly alone, hand launch, use a histart or a winch without a retriever. A highstart with 3/8 inch mandrel formed tubing from Aerofoam will launch sailplanes up to about 80 ounces very nicely.
Jul 26, 2002, 07:48 AM
Jeff Carr
Rick

Sorry to hear about the plane. I guess it was something you can pass along to others on what not to do. I agree with the other post. Young kids just love to chase down the chute and I have always given them the chance to fly. My Dad and myself have had a few take up flying from this. Even a couple of bucks thrown there way is a thrill to a young person (Even an Old Person). We sometimes need the exersise any how.

I hope your radio equipment survived OK. Its a tough thing to lose but it can be replaced. Good luck on the next one.

Jeff
Downeast Soaring
Jul 27, 2002, 03:37 AM
Registered User
Thread OP
I will probably do without the retriever in the future, half for avoiding the situation I found myself in earlier this week, and half for not wanting to give up the power used by the winch. Not much chance of using interested teens to gather up the winch line...the field is in a somewhat rural area being tucked back amongst the hills in Gilroy, and the teens here could care less for radio controlled sailplanes. Their usual sentiments are along the lines of "Hey mister, make it crash! We wanna see it crash!"

Rick
Aug 04, 2002, 07:14 PM
Old Guy
Ron Cichowski's Avatar
OOPS!!

Most retrievers I have seen are operated by a second person. The exception is one local club member's device that looks exactly like a giant fishing "spinning" reel. It is complete with bail to drop the line into retrieve position. This would allow one person to launch and then move his foot to a second pedal to drop the line to the ground. He then could complete his retrieve at the end of his flight.

I agree launches without the retriever are more agressive, but with the retriever are still high enough to thermal and with everyone using the same devices we all share the equal handicap. Also the retriever allows an easy launch every 2 minutes to keep a lot of flyers airborne with a single winch setup.

Ron
Aug 04, 2002, 09:10 PM
aka: Dances with Buzzards
ICTHRMLS's Avatar
Quote:
Originally posted by Ron Cichowski
The exception is one local club member's device that looks exactly like a giant fishing "spinning" reel. It is complete with bail to drop the line into retrieve position. This would allow one person to launch and then move his foot to a second pedal to drop the line to the ground. He then could complete his retrieve at the end of his flight.

That retriever was made by IPD (Innovative Product Developement) and is real nice to have when flying by yourself. It is too slow for club use or contest use but works great if you want avoid chasing the chute - especially when the lift is spotty.

I blew a plane up on the winch once and my sentiment was to stay with a hi-start from then on. Of course at the club level you have to learn the winch technique or go electric. It's a matter of feeling comfortable with the equipment and learning to spot incorrect rigging. Just a couple of weekends ago we averted disaster when a sharp eyed observer noticed the pilot launching had pulled the launch line thru the retriever eye guide before attaching to the plane. It would have tried to thread 110" of wing thru a 4" diameter hole!!!!

Too bad about your plane but don't give up on retrievers just yet. They really put the fun into the sport.
Aug 05, 2002, 05:29 AM
Registered User
There are two main reasons for people folding their wing launching on a winch.

The first is that they ran the winch too fast by holding the switch down too long. This can be cured by learning to use the shortest possible taps on the switch and by spacing the taps to control the speed. You can teach yourself the technique without risking your plane by holding the end of the line in your hand so that it will pull out without taking any skin. The dry run will give you an appreciation for the tension on the line versus the tempo of your toe tapping.

The second reason is that most builtup kits have very poorly designed spars. The spars are not strong enough near the wing root and too strong near the wing tips. You can double the bending strength of a wing by doubling the crossectional area of the top spar caps on the inner panels. This costs less than $1 in materials and less than an ounce in weight. The tip panels' spars are already over sized and don't need beefing up. The bottom spar cap never carries more than half the load it is capable of because it is about twice as strong in tension as the same size top cap is in compression.

If the spar caps were sized to match the bending load along the span, they would taper in both width and thickness but that would be more of a building challenge. Tapered spar caps would be three times as strong for the same weight as uniform spar caps. They would be much lighter at the wing tips which would improve maneuvering and thermal response too.

The shear load varies linearly from zero at the tip to maximum at the root. Therefore, the shear web thickness should taper along the span.
Last edited by Ollie; Aug 05, 2002 at 05:37 AM.
Aug 09, 2002, 07:53 PM
<>< AKA W4BPS

Retrievers


We here in Tullahoma have auto line pick up arms on all our retreivers and one man can launch and retrieve with ease..Have been doing it for years...I can scan pics of the winch/retrievers/trailers we use here.. Better yet stop by Tullahoma, fly witha great bunch of guys and see it in action...A local person here sells these retrievers too...Brian Smith
Aug 10, 2002, 08:07 PM
Old Guy
Ron Cichowski's Avatar

Re: Retrievers


Quote:
Originally posted by BrianSmith
We here in Tullahoma have auto line pick up arms on all our retreivers ...I can scan pics of the winch/retrievers/trailers we use here.. Better yet stop by Tullahoma, fly witha great bunch of guys and see it in action...A local person here sells these retrievers too...Brian Smith
Please do scan for all those of us too far away from Tullahoma. Enquiring minds want to see.
Thanks, Ron
Aug 10, 2002, 08:30 PM
<>< AKA W4BPS

E-mail address


I am a computer dummy....I do not know how to put the pics on here, but if you'll send me your e-mail address I can scan them to you..Then maybe one of you all knowing wonderful folks could put them on here..?? Thanks..Brian


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