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RE: Europa-List: Maximum flap extension?

Subject: RE: Europa-List: Maximum flap extension?
From: Christoph Both <christoph.both@acadiau.ca>
Date: Mon, 4 Aug 2008 22:21:06
Hi Frans:
I have a Classic TRI conversion. I also ended up with less flap travel, 
measured with a digital level affixed to the flap top surface. I have 
max 26 degrees. I do trust my digital level and so I phoned the factory. 
They said for  TRI 26 degrees would be just fine.
I still feel 30 degree would be better but I guess the flight test will 
show.
I would be cautious of re-drilling the lug, effectively moving the 
pushrod more to the centre. This is why: you definitively need to have 
sufficient material around the new lug hole (I consider a full diameter 
of the bore an absolute minimum). But moving the new bore this much 
inboard while keeping material standards and building practices up will 
most certainly be more drastic than what you want to achieve. In brief, 
you will get most likely more than 30 degrees - NO GOOD.
Call the factory and ask what they suggest. I can see a solution by 
welding on an additional layer of same steel to the lug and then 
re-drill to the correct hole location (after lots of experimentation 
with cardboard templates etc. !). This will definitively fix it.
Christoph Both
#223 Wolfville Nova Scotia

________________________________

From: owner-europa-list-server@matronics.com on behalf of Frans Veldman
Sent: Mon 8/4/2008 7:22 PM
Subject: Europa-List: Maximum flap extension?


<frans@paardnatuurlijk.nl>

Hi,

I just finished installing the flap drive mechanism. My assumption was 
that the strap on the outboard flap hinge determined the maximum flap 
extension, i.e. 30 degrees. So when I installed the flap drive tube, I 
made slots in the fuselage to accommodate the entire range for the 
flaps.

To my dismay, after installation of the actuator, the flaps only use 
2/3th of the available range. The actuator reaches its limit far before 
the strap of the outboard flap hinge reaches its limit.

To be sure, I measured the difference in angle of the flap, between 
fully retracted and "fully" extended. This is only 24 degrees! I 
confirmed this with a digital gauge. Now I don't see how I can have done 
something wrong with this, as long as you don't cut the hinges or 
reshape the flap drive tube, you can't alter the maximum flap extension.

As a further test, I temporarily attached the Europa flap indicator 
decal on the flap and wing, and to my surprise this decal tells me that 
the flap, fully extended, reaches 30 degrees...

Several questions cross my mind:

1) Is my method to measure the maximum flap extension correct? Does "30 
degrees flaps" actually mean that the flaps have rotated 30 degrees?

2) Has anyone else actually measured the maximum flap extension? The 
build manual doesn't tell you to measure it, but I suspect I'm not the 
only one who wants to measure everything related to the controls. Or 
does everyone else just trust the Europa flap indicator decal?

3) Why do I only get 24 degrees of flap extension? Maybe on the mono 
wheel it is reaching 30 degrees, but on the tri-gear the electrical 
actuator is just too short so it limits the flaps to 24 degrees?

4) If I drill another hole in the lugs of the flap drive tube, closer to 
the rotation center (i.e. truncating the lever action of the lugs) I 
will get more flap travel (at the cost of a slight reduction in flap 
drive power). Anyone tried this? It seems to me a safe way to fix this 
problem.

5) What is actually the maximum flap extension one can obtain? I suspect 
that it is possible to actually get more than 30 degrees if the full 
travel allowed by the outboard hinges is fully used. (I'm flying a 
Cessna with 40 degrees flaps, and I really love these 40 degrees flaps). 
Anyone tried/implemented this?

Thanks in advance for any answers.

Frans


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