LET Model JS1 is here!

[tewatson]

Two of us in SoCal just received our LET 33% JS1 racers...I believe they are the first two in the US. The extremely thin wing section and high aspect ratio suggests these things should really move on the GPS Triangle course. 7 meter span, flap and aileron LDS linkages are all completely internal, and the wings carry two ballast tubes on each side. Very high level of completion - the model is delivered with all 10 wing servos installed, wing wiring and fuse side wing harnesses done, and the retract servo installed. Mounts are in place for the elevator, rudder and wheel brake servos.

This is my first LET model so I have no baseline to compare with, but Dennis Brandt had a close look today and he feels that LET has really upped their game on fit and finish.

Remaining build work should be fairly straightforward and I'm using PowerBox equipment for battery and servo management, dual redundant JR DMSS RXs, and a JR 28X radio sends the signals. Looking to debut at the Visalia Spring Aerotow this May.

[ARUP]

WOW! That is sexy! Any bottom surface of the wing pics?

[tewatson]

Didn’t take any. No control linkage bumps, all red wing and stab lowers.

[Stew2]

What an awesome airframe!! Looks outstanding! Is the wing root fillet prototypical or because they are using an existing fuselage? I can't imagine that LET has not done a fantastic job with that transition, even though it is very unique. What is the wing chord at the root? How does it compare to the Antares chord? Wing chord helps immensely with visibility at altitude for me. Looking forward to seeing the powerbox install and how that all interfaces with the DMSS hardware. Congrats on an outstanding model!

[tewatson]

My understanding is the full-scale JS1 was based on a pre-existing fuse (ASH-26?) so the wing root transition accounts for that. Here is a pic:

https://en.m.wikipedia.org/wiki/Jonker_JS-1_Revelation#/media/File%3AJS1_FullRes-3.jpg

JS1 root chord is 256mm, Antares is 270mm.

[Stew2]

So, the wing fillet transition is scale!! Cool, I was guessing that it was the model manufacturers making the use of an existing fuse, but not so! Kudos to LET for including that detail. Sorry for my lack of knowledge. Really neat! Seems like this JS-1 should be very similar to the Antares in visibility at altitude.... Hmm, I have no trouble seeing the Antares, so.... Honey, have you seen this new sexy glider on the market?? It is awesome, just like you.....!! Thanks for posting. With the wing servos factory installed, it should be a fairly quick build/prep.

[DennisB]

Tom brought the JS-1 to my house Friday for its first put together, and no doubt LET has upped the game, bottom skin hinged surfaces with wipers on top, all the drive systems are internal for a VERY clean wing. I really like the retract they installed, they have finally moved on from “that” retract they have used for so long with its rather awkward geometry, this new retract looks superb and it also has a wheel hub brake. The GPS racing class is attracting quite a few customers that might not otherwise make the jump to scale soaring, 2 JS-1 ‘s in SoCal and 5 ASW-17 racers arriving later this year, all here in SoCal. Can’t wait to see all the new toys and pilots.

[jgallacher]

Come on Tom nose to the grind stone. get it ready for the Spring Aerotow in Fallbrook April 7th 2018. Would be a hit.

[BobM]

Congratulations on the new JS-1's....looks like a beautiful airframe.

Looking forward to seeing pictures and information on your build. The 28x with the PowerBox equipment should work extremely well.

Bob

[ErichS]

Its calling your name Len.....
Very nice looking.

[lenb]

I'm an H-models snob...

But then again, its pretty nice.

[Steve P]

I, on the other hand, am a Let-lover.

Thanks for sharing the photos. Notching up the QC and swapping out the $#!+ retract have gotten my attention! Knowing that the earlier skuttlebutt about the wing flare is actually scale, makes me check the Wells Fargo balance...

[ARUP]

Easy... easy!... Must... resist... urge... to... p-p-p-p-purchase! ('Resistance is futile')

[RickS]

The 1/1 scale wing transition.

[tewatson]

As usual, took my time before deciding to dive into the build...although at least it wasn't three years as with my Antares. Started working off and on a couple months ago and just recently began really focusing. Since the plane was delivered with all 10 wing servos installed with linkages and complete wiring harnesses, I figured it would just be a matter of working out the fuse details.

My TPG pal Steve Condon and I ordered our JS-1s together, and we have airframe serial numbers 2 and 3. Steve started his build right away and soon discovered an issue - as delivered, all of the flap and aileron wipers are severely oversized and bind the surfaces up tight. And I mean TIGHT (one of his aileron servo horns actually stripped during initial movement testing.) The wings require a fair amount of work to correct this, along with another issue that I will detail as we go along. Not insurmountable problems, but disappointing that the planes were actually built and shipped that way.

More to come soon, as the plane is nearly flight-ready.

[tewatson]

The stab servo and linkage was first up. The horizontal is extremely thin and as designed, the surface horn position and installation were both suboptimal. The very short OEM horn did not line up vertically with the servo horn, limited the servo throw that could be used thus reducing precision, and it was threaded into a shallow pan-style receptacle epoxied to the surface mid-chord. On maiden day for Steve's plane, this insert actually just popped out of the stab on its own (luckily while it was on the ground.)

A longer horn positioned at the hinge line would provide better mechanical advantage AND allow more of the available servo throw to be used. I also like L-bend connections, so one is not repeatedly fiddling with a clevis in a tightly confined space. So, a revised design solved all the issues. Fabricated a new, 50% longer surface horn from G10, and installed it in a slot that goes through to the top skin, along with a support piece that covers the original mounting hole and provides some additional lateral strength. This also corrected the linkage geometry such that a vertical bend in the rod was not required.