Just for fun sake..... where in the States are you?
Mike Duane
Europa XS Conventional Gear
Las Vegas, NV
Sent from my iPhone
> On Oct 1, 2018, at 12:27 PM, n7188u <chmgarb@gmail.com> wrote:
>
>
> I will be delighted to share what I did. Just give me a little time because I
work far from home and by the time I get there I work on the plane and then I
am too pooped to sit in front of a computer. I will send bits of info and
pictures
here and there. enough to keep the conversation fun :)
>
> So that we are clear on the kind of feedback I can give:
>
> 1.- I am not an expert Europa builder so whatever I do may or may not work.
> Seems
to be working for me though. Also, I am in the USA so anything I show here
may not be possible in Europe. However, the concepts still apply.
>
> 2.- I am a Mechanical Design Engineer, Aviation Mechanic, built a Cozy mark IV
and worked for an Aviation Structural Engineering firm at one point in my life.
Not to rub it just so that you know I am not totally insane when I try to
do a change (although I never claimed I dont make mistakes :)). And I do know
there are probably better ways to do things. Also, as Burt Rutan used to say,
if you modify it, you are now the designer and the test pilot of a brand
airplane
design!
>
> 3.- Rule number one: dont force or bend anything into place, just let stuff
> find
its happy relaxed state and then attach. Simple concept, hard to implement.
If you have to bend or force anything then check its effect on the control
system.
>
> The issue I see with the control system assembly in the Europa has to do, in
my opinion, with how flexible everything is in these planes. I discovered the
hard way that when you install the controls in the cockpit module and the aft
part of the fuselage, any miniscule strain placed in the CM or fuselage bottom
afterward will cause small distortions that will increase friction in the
system.
I'm not kidding, I spent hours, by inserting one cleco at a time and checking
friction, to find which clecos would increase friction in the controls (and
which would reduce it). I would then leave that cleco out and fill the small
gap with a little extra epoxy. If the gap is large then thats a story for
another
lengthy writing.
>
> With that said, I found that to achieve smooth controls is to avoid component
distortion. And a cleco distorts too much in this plane! And so why am convinced
that the right way to do this would be to bond the CM in the fuselage, cleco
the top perfectly and then bond all the control bearings in place. Maybe
impossible
to do but would be ideal.
>
> BTW, I may still end up with stiff controls since I have no idea if anything
later on will cause stuff to strain and bind the controls. Probably yes. But my
hope is that my effort will minimize the binding. Right now, a light breeze
will move the stabilators and I am happy! Lets see if I can keep it that way!
>
> BTW, and I learned this from Bud Yearly, beware of cradles that fixate the
> fuselage
too much. If you build like that and then remove the cradle things will
go where they want to go and thus create binding. This thing is like a gigantic
bunch of springs that are tied to each other. If you constrain them and then
relax them, they will find a balance and it may not be where you want it. I
do have a cradle but nothing touches the fuselage except a small table at the
bottom of the forward fuselage in the CM area and thats it. I screwed the
fuselage
to this table through the CM flanges to keep the bottom flat and level.
Essentially
what the manual tells you to do but instead of a bunch of pallets I
have a nifty table on wheels. Then I still have the advantage of a cradle with
minimal distortion to the fuselage. Again, dont know if any of this will bite
me in the you know what later on but that is how I am doing it. Oh, wait, did
I said I screwed the fuselage to the tab!
> le, oh boy, lets see what happens when I let go, or put it on the gear, or
> hang
the engine or sit on it, etc, etc, etc :)
>
> Pictures and explanations will follow on all this I talked about.
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=483511#483511
>
>
>
>
>
>
>
>
>
|