Tow Release Location

[Trevor]

I'm planning to fit a tow release to my Gordon Waite AV36. It would have been better if I'd thought of this before fitting an FES to it a couple of years ago because the electric motor is now occupying the usual position for the release.

I've ordered the usual Multiplex release and indicated on the attached pic two possible locations, above and below the motor (I'm aware that the full size is towed by a yoke attaching to the two sides of the fuselage, but I really don't want to go down that route!).

Pitch control on this model is a little on the vague side - the elevators don't have much of a moment arm to work with - so I'd be interested in views on which of these locations stands the best chance of achieving stability on tow.

Thanks in anticipation,

[john greenfield]

Trevor

Either location will work but I would prefer the lower position as this will give the glider a more natural "high" tow position behind the tug which will make towing easier.
If space is tight in the nose an alternative would be to have a sliding pin across a slot in the fuselage side as close to the nose as you can get it. It is easy to make using a "snake" type pushrod with a metal pin screwed into the end. Glue the outer of the snake to the inside of the fuz and then cut a slot through the fuz side and snake outer about 6 to 10mm back from the end of the snake outer.

AEB

[Jilles]

Because we are talking a Fauvel flying wing here you should think about how the tow/winch hooks are located on the prototype. They have two hook on either side of the fuselage in front of the wing or as in some cases in the wing nose in front of the two fin/rudder structures. In my model I have two hooks in either side of the fuselage, just under the wing leading edge in front of C.O.G. the result is a very stable tow. The tow line is a Y string with the joint of the two lines coming together about 1 meter in front of the nose. Some pictures attached how I did this. some pictures attached and drawing of actual release(s)

[SP250]

Don't forget you always want to tow in a position higher than the tug with a flying wing as they are seriously short coupled for elevator and the downwash from the tug creates many more problems for a wing that it does for a conventional tailed glider.

John M

[Trevor]

Hmmm, lots to think about there - thanks folks (I think!). I will give the job another dose of looking at but, because I've gouged out a channel for the motor wires in the lower portion of the nose block, the upper position on my picture would be the most straightforward to implement.

Why is it that the easiest approach always turns out to be the least favoured?!

[Trevor]

Well, after thinking about this a bit more and re-reading Chris and Barry's articles on the subject, I decided to ditch the Multiplex release and go for the 'wire past a slot in the side of the nose' approach mentioned by John. This has served me well over the years in my venerable Alpina so hopefully it will work okay on the AV36.

It turned out to be a real fiddle of a job (as retrofits often are), but it's all done now. I'll report back on how it works out in due course.

Thanks again for the help.

[Barry_Cole]

Trevor,
The tug is now sorted and ready. Just waiting for the wind and rain to relent.



BC

[Trevor]

Well the AV36 got its towline baptism today and I’m delighted to say that it behaved impeccably. There were lots of people present so maybe someone will come up with photographic evidence. The only difficulty encountered was that, because the release wire is fairly deep in the fuselage, engaging the tow loop proved to be a bit of a fishing process.

Thanks to everyone for the advice - and to Barry for the tows.

[chris williams]

Proof of the pud...

[Trevor]

Thanks Chris. After a slight technical hiatus, I've now managed to update my website with this modification, including a report on the first flat field outing:
http://www.bartonhewsons.uk/home/modelf ... lease.html