Tony,
Welcome to my world.
The first Europa I purchased used had the left wing at 2.6 and the right
at 3.1. I moved the sockets in the right fuselage side to 2.6. It
flies straight and true. If you were to set both at 2.8 degrees your
fuselage will be nose down a bit at cruise, which shouldn't hurt a
thing. Just go for it.
As for your gear relationship, deck angle etc. on landing, I can only
say that the extra bit of incidence will allow you to be closer to the
stall angle at the three point touchdown and improve over the nose
visibility.
In practice I found that I can correct with flap and aileron trimming up
to .2 degrees incidence difference and you will never see my changes.
At .4 incidence difference, I have to modify the the wing leading edge
to get a perfectly straight stall.
First consider this: To be sure as Frans and others might say that
later, that all digital and spirit or bubble levels are not equal. In
fact I have one that is off .3 degrees when tested at three degrees. My
test bench is a simple 3 inch block in 60 inches and with the level
facing one direction and when the level is rotated 180 degrees putting
the scale window on the other side it measures 2.7 degrees rather than
the three. That's 10 percent off.
So it is best to set your spirit level or digital level on a dead flat
surface and check the zero to 3 degree setting. I used to set my level
at 2.5 degrees (2.5 inch board at 60 inches) 3 degrees, 5 degrees and 12
degrees for calibration purposes of the wing incidence, and tail planes
to make sure things are fairly close to the manual.
Since your sockets are only in Redux, snap them off and fix them both is
what I would do.
I have found that the best way to make sure things don't move is to
shore up the wing well during cure. Just in case the temp changes over
cure time, I block the gear also if necessary. Trigear, I put a pipe in
the main gear, and for the conventional, I block the spring gear itself.
I know that you don't really want to hear this but the standard rule in
my shop is take it apart and put it together (normally about 5 times)
until it is repeatable and easy to do. That means when building glider
wings, or rigging the plane, or hanging the cowl if you try to do things
in one shot, you will have to redo it to get it right.
The worst thing to happen when rigging wings is to have the left spar
creep aft during the socket build up then it causes so many troubles
down the road. Take your time, make sure it fits all around then tack
it in place.
The only difference between a professional build and an amateur build,
is I know how to fix my mistakes before it affects something else.
As for the tail dragger, good luck. It is best to modify the gear to
get the position of the axle to leading edge of the wing MAC (about 2/3
out on the wing from fuselage centerline) over the axle with the
fuselage in level position. Contact Grove, as Bobby Grove has a couple
of solutions. (New gear or 1/4 inch steel plates to increase deck angle
and move the axles back about 4-5 inches. As the gear as is, I find it
un-gratifying to fly the gear as designed. It is very tough to wheel
land the conventional due to the spring stiffness and forward position.
With a 10 Knot cross wind I can land on one main and do a wheel landing
with ease and no tire wear (without the crosswind, tire wear on a wing
low slightly slipped landing is more than I care to pay for). Three
point is not a problem. It is quite tough to teach a new guy how to
land and takeoff with the gear as set. It's a mono except it doesn't
fall over when the wings are pulled off. If you hit mains first with
any vertical component, the tail drops faster than you can react and
combined with the extra lift from the drooping tail added to the gear
spring reaction, you get launched back in the air, then hit the tail
wheel, you over correct and down on the main again resulting in a
porpoise which continues to increase in speed and frequency naturally
and any PIO combination can be a disaster. Just go around and get the
tail wheel on first. Don't relax on roll out as between 45 to a fast
walk it tends to wander and you have to "stay on it". Not difficult to
master, it just takes practice, discipline and the ability to go around
early when it doesn't work out on first contact. Go around early and
save yourself and the plane.
I highly recommend you do not install a fully swiveling tail wheel
unless you can lock it from the cockpit as the torque of a 912S with
Airmaster is enough that a moment of inattention or failure to keep the
stick full back is a real eye opener for the new guy on takeoff if the
tail wheel is not positively locked. Next, on landing or a bounce, if
slightly sideways, the tail wheel may unlock and you will be off to the
races with no tail control but the rudder which is not effective at
really low speed on takeoff or roll out...
Find a Luscombe with a bad wheel alignment on steroids to practice with
on asphalt. Keep it straight, lower your IQ to a 2 and hold it off
until hit the tail wheel first. You'll be fine.
Regards,
Bud
----- Original Message -----
From: Tony Renshaw<mailto:tonyrenshaw268@gmail.com>
To: europa-list@matronics.com<mailto:europa-list@matronics.com>
Sent: Wednesday, July 03, 2013 10:11 PM
Subject: Europa-List: Angle of Incidence on a Classic Taildragger
Downunder
<tonyrenshaw268@gmail.com<mailto:tonyrenshaw268@gmail.com>>
Gidday,
I have set up my port wing, pulling it in tight agains the rear face
of the cockpit module and setting the incidence. I've used a digital
level and upon bonding on the LE lift pin socket I found the incidence
had changed nominally. I have attempted to make a small adjustment with
the TE socket position which is reduced but not bolted, yet. It was
suggested that I could twist the spar nominally to get the angle
accurate but to be honest I didn't like doing that although I suppose it
wouldn't have mattered that much because we might only be talking about
a % of a single degree of twist. Still, I didn't like that idea. Suffice
to say I now somehow have 2.8 degrees which is to me unacceptable, BUT,
its a lot of work to undo things. That probably isn't completely true as
I only have the sockets mounted with Redux, so I could heat them and
snap them off and start again, but I worry I'm going to do a lot of work
and may well end up right back where I've started. My pins fit nicely !
in the back of the seat, and that took a lot of mucking around, and I
worry that to undo things and redo them I mightn't get the same result.
I want to know what people think of this angle, whether anyone else has
not set it perfectly, what difference they perceive it might make on
their plane, and whether anyone has factual consequence of it not being
100% right. I do worry only about the relationship of the tailplane to
the wing, but having a fully flyable tailplane removes some of the
problems of not having a perfect AoI. The impact could be however that
at optimum in trim cruise the tailplane may be at a slightly different
angle at an optimum CoG, and the full range of pitch may be not what was
originally planned.
So, if anyone has advice I'd really appreciate input. I should also
add that I am building a taildraggers, a Bob Berube mod from Florida,
which relies on the same moments as the mono wheel by having the design
such that the a/c has a similar stature on the ground. Maybe the higher
AoI might be a bonus, and help me fly away better, climb better, but no
go quite as fast. To be honest, I don't care anymore as I would prefer
to not have to undo stuff I have done. I'm becoming pretty good at that
but unfortunately keep practicing the skill.
Regards
Tony Renshaw
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