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Valenta Salto - setup, FES and aerotowing question


John Wighton
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John Wighton

I put the feelers out on the UK Scale Soaring site and have purchased a Valenta Salto - its the version that measures 4.3m with winglets, but shares the same main wings/fuz/tail with the 4.5m version.

I actually had the choice of two, the other being subject to an online forum build article/review, was almost twice the price and had been well flown.

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The model was obtained as used but it turns out it has not flown.  It was balanced to around 93mm from the root LE using 650g of lead.  I weighed a Hacker A50-16L and found it is less than the lead, hence a rational choice  was made to de-install the nose release and install the Hacker with a 'pop-off' FES drive (the FES Ex-Uni8 system and 8mm to 6mm adapter being the right match for the A50-16L v2 kv272).  I do also have an A60-20S glider version (which is slightly lighter strangely) turns kv245 and would possibly have needed a bearing in the nose to avoid whirling.

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Diagram is from Hacker GmbH

I used eCalc and estimated that the following setup to try out.

Hacker A50 16L, 4500 6S LiPo, YGE 95LVT ESC, FES Ex-Uni8, GM 20x13.  This pulls 1225W, 59A, 4950rpm and should give 7 mins mixed flight time or 4.3 min of climbing. 6.8kg of thrust.

As I have around 40 5S packs from old F3A models, I will also try the following:

Hacker A50 16L, 5000 5S LiPo, YGE 95LVT ESC, FES Ex-Uni8, GM 23x13.  This pulls 1115W, 65A, 3930rpm and should give 6.3 mins mixed flight time or 4 min of climbing. 6.5kg of thrust.

I aim to hand launch it or use my Launch Cart (or taking the pee of our German cousins, Mittagswagen (Lunch Cart)).  The FES unit takes 1 sec to demount and leaves a nice clean nose sans spinner.

Has anyone successfully sited a nose release about 80mm back and flush with the lower profile (see sketch below)?

image.png.9bfd5ea0acd2faaeb9d302be4cfcd6e1.png

 

 

I figure this might induce a marginal nose-up pitching moment on tow.

The brakes on the wings are recessed around 0.5mm.  Does this impact the glider performance? I think it might be possible to move the neutral position as the units are electric.

Any feedback on control movements is also welcome.

Regards

John

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That position is commonly used with FES in scale models and works well.  There won’t be any noticeable difference under aerotow.  Look forward to seeing this in action John.

Simon

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Position of the aerotow release does seem to be critical. My Alpina has it on the side about 2 inches back from the tip of the nose. 

I would be tempted to resolve the closed brake issue, it can't be helping.

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John Minchell

I would suggest John (an opposing view to Wookman above) that the position of the tow release is not critical. 

We just had the last Sherlowe aero tow of the year and my Lo100 has the release on one side and 3 or 4 inches back and below the nose and many others have the same.  A 5m Valenta Blanik 213 with the tow release about 12 inches back from the nose, on one side and under the front FES prop blades showed no discernable issues on tow so I would say - nothing to worry about.

Brakes below the wing surface will create some turbulance and level them up if you can, otherwise fly it and don't worry.

My Thermik XXXL for GPS has the same issue but the ends are flush and the middle bowed down so I left them - it flies fine. 

The pilot needs to get much better (me) before I consider the miniscule extra efficiency in correcting the moulded cap strip bowing being of any use to improve performance.

John M

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John Wighton

Thanks John,

I think wookman left a "not" out of the sentence (maybe)!

I will place the tow release low and aft on the centreline. It might need a 3d printed plug to keep the muck out.

I had a Valenta Chilli double carbon that met its end at a GPS training session, I replaced it with an earlier GPS version (unbuilt) as the later versions have spoilers (just like the Salto) - everyone I have seen fly in that config tapes over the spoiler as it never seems to sit level.  But the flaps and ailerons on the Chilli can be set up for crow which will be less easy on the Salto.

Anyone have mixing data, ideally as a Futaba model memory (T32MZ or T18MZ)?

JW

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John Minchell

John, I had the Baudis Salto and the full CROW down flap on it (with elevator compensation) stopped it in its tracks for an easy landing - so your Valenta Salto will be pretty much the same, judging by the two or three I have seen on the Long Mynd. 

I have the full Baudis Salto set up still in my MPX Profi Tx if anyone (Frank) can advise me how to get it out and onto a spreadsheet for emailing to you if that is of any use.

John M

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