If wheel landing, at the instant the mains touch the runway, "stick it on"
with a fair amount of forward stick - bringing the tail up while the mains
are on keeps the wing Angle Of attack (AOA) well below that required for a
second lift off or "bounce".
If 3-pointing, at the instant the tail is on (even if the mains aren't yet),
"stick it on" the runway with full aft stick - the tail wheel can't go down
into the runway any more then it is, so the wing's AOA can't change any more
then what you have at touch down - at worst case, the wings will keep the
mains in the air until enough energy is lost when they too touch down.
In both cases, the plane is stuck on the runway - fwd stick in the first
case, aft stick in the second.
Cheers, Bob 612e
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com]On Behalf Of Ken
Sent: Saturday, December 22, 2007 7:10 AM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Rebel stab incidence
OK I'll toss out my thoughts while we're waiting for the Rotax guys to
speak up...
Any aerofoil change (VG's or cuffs) likely affects the center of lift
which likely affects how much up elevator is needed.
Changing the wing incidence is really difficult. I'd judge it not worth
the effort. You'd almost need to change the cage or rear mounts when
building the fuselage and it would mess with the upper and lower wing
fairings and the windshield or the door closing. The Rebel is unique and
it obviously works fine without mods.
119R with the STOL cuffs definately does not stall in the 3 point
attitude so I do consider it to be tricky to land compared to airplanes
that stall and stay down in the 3 point attitude. OK so it is different
and it's fun to learn how to exploit its characteristics. Landings are
fun! My best landings are tail first which for me is only achievable
with the stick firmly in the rear stops. Three points are fine as well
but touch a mainwheel first and it really wants to fly again and often
you better have power on to cushion the second touchdown or do the go
around. More than once I've been down (all three wheels) for several
seconds and had a gust lift me off the ground again. That can happen
with any taildragger and the Rebel handles it well when it does happen.
I like the abilty to dump the flaperons after touchdown with the manual
flap handle.
Some folks have commented that they think I'd like longer main gear legs
for landing but I do not agree. Other issues would surface. I still
intend to try the VG's on the stab in warmer weather but I'm not
convinced that will help much now that I have learned how to get the
tail down most of the time anyway.
The fairly heavy STOL taildragger that I used to fly had the same 4415
wing but it had 3 times as much flap deflection and twice the aileron
deflection which did guarantee a stalled wing in a 3 point attitude.
Most guys avoided full flap unless on floats when they kept power on.
You had to pay attention as it was easy to develop a high sink rate at
slow speed and then you needed serious power or altitude to recover. Can
you say "way behind the power curve"? I don't think the Rebel has
enough flap to significantly affect drag or stall attitude but it will
go around just fine with full flaperon. It takes very little power to
arrest my relatively mild Rebel sink rate which I think is at least
partly due to the STOL cuffs. I don't have experience on my airframe
without the leading edge cuffs for comparision. Anyway it is easier to
stay out of trouble with the Rebel and it has great capability to
exploit if you wish to.
Ken
(still a new guy with only 150 Rebel hours)
Tim Hickey wrote:
Hello all and Merry Christmas.
Let me jump in here with a related question. I have been keeping my ears
(eyes?) open regarding the angle of incidence issues. What caught my
attention was a remark several (Many) months ago by Rick Harper about his
landings not being so good because the tail wheel was hitting the ground
well before the mains while trying to full stall land his bird. I realize
that no one answer will fit all Rebels, but this comment made me wonder if
perhaps there could or should be some adjustment to the angle of incidence
of the main wing. (which I do not even know if this is possible) From
Rick's comment I deduced (always dangerous) that maybe the angle of
incidence should be slightly increased so that at stall the airframe was in
a perfect three point attitude. But... and there is always a but... I have
no idea where his cg is, and I do recall that he is running an O-320, which
I will not be doing.
How about you Rotax guys: Do you find that the three point attitude and the
stall seem to come together just about right?
Tim Hickey
R808
----- Original Message -----
From: "Walter Klatt" <Walter.Klatt@shaw.ca>
To: <rebel-builders@dcsol.com>
Sent: Friday, December 21, 2007 7:55 PM
Subject: RE: [rebel-builders] Rebel stab incidence
I think just putting them on the wings will help with getting the tail
down.
I know that on floats my angle of attack is now much steeper before the
stall than without the VGs. I never did put them on my stabs on the Rebel,
as I have never run out of elevator authority on floats.
Walter
-----Original Message-----
From: mike.davis@dcsol.com [mailto:mike.davis@dcsol.com] On Behalf Of
Ronald
Shannon
Sent: December 21, 2007 5:24 PM
To: rebel-builders@dcsol.com
Subject: Re: [rebel-builders] Rebel stab incidence
Regarding flare control, does anyone have experience with the effect of
VG's
on the bottom rear of the stabilizers? (I vaguely recall some prior
discussion about this, but tried to find it recently without success.)
Ron
On 12/21/07, Ken <klehman@albedo.net> wrote:
...There are also numerous comments
about needing lots of up elevator for landing on wheels so this will
help that as well.
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