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Jul 29, 2001, 11:17 PM
Blew out my flip flop
David Hogue's Avatar

Bungee setups for light edf's?


Had my first a-10 flight today, see results at http://www.ezonemag.com/disc/Forum6/HTML/001969.html and although I do OK handlaunching my simple 400 and others, I have a problem with my shoulder that is not going to allow me to handlaunch this thing, and I had rather bungee than bug a buddy every time, plus I fly alone quite a bit.

Anyway, what kind of material, and how much line and bungee material would I need to launch a 16.5oz Dare A-10? And, what will be needed for a towhook in the nose?


Thanks in advance,

David
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Jul 30, 2001, 06:49 AM
Registered User
Greetings -

Take a look at: http://www.skybench.com/ and click on high starts. Ray sells the rubber only and I would recommend the rubber meant for under two meter size sailplanes. There's enough rubber there for a couple of launchers the way we would use it and the price and quality are quite good. You could possibly use a single piece for models the size of the A-10 and double it for larger models.

BTW - nice model!

Fly Fast! Mark
Jul 30, 2001, 11:36 AM
jrb
jrb
Member
jrb's Avatar
I'm flying a 16 oz. twin EDF, and also looked far and wide for a light weight and not too expensive bungee material.

Finally found some latex(like) tubing at my LHS; its from the chemistry set area and by "Pefect", the guys who usta do some C/L 1/2A tanks and stuff.

I think the roll cost $11 and is about 15' long w/OD of about 1/4" and thin wall.

Stetch is to 2.5 times ad have about 7' of nylon cord.

Works great!
Jul 30, 2001, 10:10 PM
Blew out my flip flop
David Hogue's Avatar
Hi guys,

I ordered some 1/8" ID, 1/32" wall surgical tubing from a local med supply today. When they get it in, I will be able to look at it, get a feel for the stretch/power, and either buy the whole spool, or by the yard. JRB, this sounds about like what you have.

Now, what about the hook?
Jul 31, 2001, 10:55 AM
Registered User
byoung's Avatar
David,
After having three not so pretty hand launches with my Mirage pusher, I decided to add a launch hook and use my pedal launcher. Boy what a pleasure now to get a good launch. I used some of the 2M size rubber and limited my pull to about 1/2 to 2/3 of what I use for the T-33. The best would be to get a fish scale and pace off for 3-5 lbs. of pull. With the high lift A-10 wing you shouldn't need more than 3 or 4 G's of pull.
For mounting a hook: I made up an 5" tall "H" shaped piece to mount the hook. The vericals are .070 carbon rods and the horizontal is 3/4" wide 1/16" ply with a second 1/16" doubler right where the hook screws in. The hook was a small L-hook from Home Depot. The rods were glued to the ply center with epoxy and a couple layers of 3/4 oz. fiberglass. I cut some slots in the foam Mirage and epoxied to H flat to the bottom. To spread the load more over the foam I added four 1" square 3/4 oz. fiberglass patches over the carbon rods.
Good Luck,
Brad