Tow Hook Connection/Release?

[Tango Juliet]

In doing research for my upcoming Slingsby Sedbergh T21b build, I'm having a bit of difficulty obtaining good detail of the tow release under the nose. Chris Williams design/plans don't show this at all (presumably because he is mainly a slope soarer). I could use the tow release sold by www.iflytailies.com in the nose, but that wouldn't be accurate to scale (the hole in the nose is for adding a slug weight for single pilot use).

I had assumed that it would look something like this:


The Southwest Soaring Museum was able to send me a photo of the tow release on their T21b and it's completely different. It's not the best photo, and I'm having a hard time really understanding what I'm looking at installed in the aircraft.


At this point, I'm considering fabricating the upper one unless someone can provide me with better images of the lower (actual) one. Any/all help greatly appreciated.

[ARUP]

Just make a 'hole' in the fuse to appear as your picture. Inside the fuse and above that 'hole' a segment of piano wire goes across it, along the fuselage long axis. Capture the wire with tubing either side of the 'hole'. The wire retracts rearward to release the loop connected to the tow line's clevis. Naturally, the tube segments that contain the wire have to be robust and solidly mounted.

[Tango Juliet]

And I've been considering going that route . I did learn that the 1:1 is using a Tost release, and not the Schweizer style that I thought they were using. Scale is the illusion of reality, so only what can be seen externally would need to look like the 1:1, the internal components and functionality need to be what works for R/C aerotow.

I haven't been to an R/C aerotow except for the silly attempts of some club members who cobble together nitro planes and simple 2m sailplanes - which sometimes work - so I'm looking forward to the NARCA Aerotow in October to look at a lot of this stuff up close and answer some of my own questions.

[Marc B]

TJ,
Here is a drawing from the owners manual. Hope it helps.

[Tango Juliet]

Thanks Marc. I actually received that image from the contact I made in the UK over the past week. He's come through with quite a bit of the details I was looking for. I'm still waiting for a better photo of the location from the exterior of the aircraft so I can make my placement correct.