EWD on Tangent Mistral 4.7m

NEP

User
Moin,

Sorry for keep thread in English :p

I have recently bought a second hand Mistral in good shape - my the first testflights indicates a "tail problem".
The dive test indicated an over stable glider. I moved the CG a bit back at lifted the tailplane leading edge a bit (increasing the angle of incidence).
That helped a lot.

The tailplane is misalligned in all three dimension, so I need to rework the support console on the tail fin. Also the EWD, because....

I have measured the EWD which shows to 2.5-2.6 dgs less than the main wing (which in my notation means -2.5 dgs) - too much downwards tailforce!
The manual (bauanleitung) says 'just' EWD 1.5 dgs - but is that negative or positive???
My gut feeling says that 1.5 dgs is positive - but it could also just mean -1.5 dgs (one case meaning that the glider currently have 1 degree too much negative EWD; or on the other hand is 4 degree wrong, in case it has to be +1.5 dgs)...

1) Any one "out there" who have had the same EWD experience/adjustment; or (even better)
2) One who is able to clearly state: 1.5 degree less than the main wing or 1.5 degree more than the main wing??

Grus
//Niels (Dänemark)
 
The tailplane is misalligned in all three dimension, so I need to rework the support console on the tail fin. Also the EWD, because....

I have measured the EWD which shows to 2.5-2.6 dgs less than the main wing (which in my notation means -2.5 dgs) - too much downwards tailforce!
The manual (bauanleitung) says 'just' EWD 1.5 dgs - but is that negative or positive???

BTW Niels: will all respect but your measurements must be way off. The Mistral will not fly with an EWD of minus 2,5 degrees. It will undercut with a setup like that: keep diving when doing a dive test.
Please check the EWD with this tool:

http://www.rc-network.de/magazin/trickkiste/trick05/trick05.html

Tangent planes do have a tendency for having an incorrect EWD so please measure correctly and set the plane up with an EWD of (+) 1,5 degrees

Good luck and regards, Maarten
 
EWD Mistral

EWD Mistral

Hi Niels,

no doubt about it, + 1,5 degree. Wish you much fun with your Mistral, its a famous glider.

With best regards

Joachim
 

NEP

User
Hi,

Thanks for answering everybody...

I was never in doubt about the 1.5 degree - but if EWD is false interpreted it means quite a difference.
This sketch - which explains the German way of defining EWD - gave the right answer:
(though it is still a bit odd notation; since the tailplane has LESS angle of incidence compared to the wing (when using the same horisontal reference)!

http://www.rc-network.de/magazin/trickkiste/trick05/trick05.html

And, it has now been corrected to have +1.5 degree EWD (which before at least was +2.5 degree , hence, 1 degree too much that seemed to kill it's performance and supreme gliding characteristics).

I fullsize aviation (from where I have my theory based) one would instead use the term; Longitudinal Dihedral
In this notation an EWD of +1.5 degree would mean a longitudinal dihedral of -1.5 degree (quite a dirrerence!) :)

As MaartenX pointed out about Tagent and false/incorrect EWD: Yes, again it was no exceptance to the rule :D


Grus
//Niels
 
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