Hi there,

this week end I tried my new HF-Model ASW-28 3 meter sailplane.

The glider is setted by the book ( most forward CG for the first fly and all flying surface are moving (debatment) as indicated in the book)

As soon I try a turn with the glider and this in both directions the saiplane begin to turn but sundently at about 30 degree angle the plane stall.

Any idea what append or what I can correct .

tks
tiju

Assuming your CG is right, and you have enough speed through the turns... (sounds like you fly too slow...)

First I would have checked the wings for warps. Maybe they are twisted so there is some wash-in?
Do the elevator require much trimming? If so the decalages could be wrong. Measure using an incidense-meter.
Else: use differential throws on the ailerons. Usually 100% up and 20-40% down movement...
In addition to speed; use the rudder through the turns! This is important.

Joo has the right ideas! Plus, is the CG as indicated in the plan/instruction correct? I have built many planes where the maker has quoted it wrong! If all else fails add some lead to the nose. It may make it less responsive but should work. Then you can cut back on the weight until it suits your style.

I have the 4 meter version of this plane and the few times I've flown it, I have never experienced a tip stall. I agree with Joo, you probably have a bit of washin, instead of the proper washout. I am not too sure about the CG thing, because I find most European planes in this size range, 3 to 5 meters, with the CG already set too forward.
You should assemble the plane and look at it from the winglet or tip and see if the angle decreases from the wingroot to the tip, in fact the tip maybe angled slightly down in relation to the wingroot. But if you see that the tips are angled higher or the same relative to the root, you probably got a problem but it's fixable. Also be aware, that one wing maybe perfectly fine and the other, the one you turned into, may have the washin problem.

I had a smal 2.6M ASW-27B which tipstalled quickly if I pushed it to hard in turns. I got a very good advice which solved it for me: “move the CG backwards”. The theory is that “a nose heavy plane have to fly at a higher angle of attack” (I don’t know the aerodynamics behind this though). When a nose heavy plane is flying at a high AoA just to maintain level flight, it’s more likely to put it at an AoA past the stall limit when turning.

Wiker: I assume you have the MPX ASW27B? This is a beautiful bird on the slopes, but they use a modified RG15 profile. This profile works good, but are known to stall in hard turns
There are some of these planes in my club (I have one yes...) and they perform extremely well when flown on good slopes. But the profile is not good when you want to do F3F-turns, especially the wingloading is a bit too high for tight turns. Don`t think any of us have moved CG backwards, but might be worth a try.

I think the key there is to reduce the decalage angle slightly at the same time. IIRC the horizontal stab bolts onto the top fin, right? Shim it with a piece of tape at the front, test fly it, and season to suit. This technique really worked with my Destiny/Floh XL.

jooNorway: Yes, it was a Multiplex ASW (dont have it any more), and I was doing F3F style flying with it. Mine was very heavy though, about 2300g and 62g/dm^2 wingloading. I moved CG back to 74mm, and had no more tipstall problems.