Let me start by asking exactly what is a tip stall and how do you handle
OK, I am going to build a P-51 ARF and am looking for a way to eliminate so
called tip stalls if thats possible. I have "heard" that if you glue a
triangle shaped lenth of balsa on the upper trailing edge of each aileron,
this will solve the problem. The balsa piece is triangle stock from a
quarter inch square stock. Does this make sense?
"Are you still wasting your time with spam?...
Stalling is loss of lift. It can happens when airspeed is too low
and/or attak angle is too high. When it happens at wing tips before
roots you loose also aileron control. At safe altitude you can usualy
recover. Not so at 2' over track. If you add (ugly) triangle balsa
pieces as you describe or slightly raise both ailerons than tip stalls
is retarded but not eliminated. If you scratch build you can add some
tip washout (less angle at tip than root). For an ARF check if that
washout is not readily present.
Doesn't really make sense, and it's ugly, too. Washout helps prevent
tip stalls. This is angling the tip of the wing down at the leading
edge. This keeps the tip flying when the root stalls. Keeping the
plane above stall speed also helps. :) If you fly too slowly, and/or
at too high of a AOA, ANY plane will stall. Keep the weight low, too.
A lighter plane has less wing loading, and will fly more slowly before
stalling that a heavier plane will.
I've never heard that the P-51 is prone to tip stalling. What makes
you think you'll have a problem?
Tip stalling is when the wing tips stall before the root. Usually one side
stalls first and the plane flips over...crash. This usually happens on
landing approach where the AOA is too great or airspeed too small. I
happens more frequently with higher wing loading.
That said, a P-51 is nore prone to tip stalling than any other model. A
heavily loaded Extra or Sukhoi will do exactly the same thing.
Which ARF are you assembling? I have flown several of the EZ 40 size and
they are a dream to fly with no bad habits. Some of the others which are
near clones are the same.
Just about any 'plane will tip stall if conditions are right. I don't know
about this particular one but most generally a heavily loaded warbird is
seen to tip stall on takeoff. This is a result of using aileron to steer
instead of rudder when speed is low and the nose is high. The trick of
adding triangular strips to a wing is to allow the inboard section to stall
before the outboard. However, the strips are applied to the inboard L/E not
the ailerons. Even with them on, it will do little or nothing for bad
flying. It strikes me that putting something on the ailerons would cause
some serious stall problems on the outbd end of the wing. In actual
practise, next time you are near a Cessna 150, take a look at the L/E near
the cockpit and you will likely see some stall strips. Do an "image search"
on google using "stall strips" as the search argument. The first couple of
hits show you and tell you a great deal about this method.
The other way around. Aileron without rudder will cause a
slip, which is relatively safe. Rudder only causes a skid, which is
asking for a wing drop at low speed. Flight should be coordinated to
avoid slip or skid.
Of course, using aileron to pick up a wing when it's dropping in
a stall can often deepen the stall and make it drop faster. Depends on
Ummmm... I respectfully disagree...
Gord's post was correct IMHO...
At too low airspeed, the AOA is necessarily high to
Applying aileron (only) in this situation, (usually recovering
from the turn to final) causes an adverse yaw. This down going
aileron on the wing that is already travelling slower on the inside
of the turn is slowed even more by the adverse yaw, - the down
aileron increases the (effective) AOA of this wing tip even more, and
the inside wing tip stalls, rolling the aircraft OPPOSITE to the
applied aileron command.
Soooo... the "I got hit" call is heard, - after all, it DID
roll OPPOSITE to the stick movement ... right?
I believe what Gord is saying is correct. Applying aileron
ONLY in this situation is a recipe for disaster, and is too often the
result. Add this mishandling to a clean P-51 with tapered wings,or
the eliptical wing of a Spit, and a (usually) higher wing loading of a
warbird, and many end up in a pile because the pilots were never
trained to fly properly.
LOTS of rudder is required in this situation, and if it skids
the aircraft out of the turn, speeding up the inside wing tip (good)
the aileron can be used (a bit to help) with greater safety.
One should LEAD (apply first)recovery rudder, BEFORE the
aileron is moved.
Watch others fly, and observe how many fly around with their
left thumb on the box, reaching the left stick only to adjust the
If this is you, please learn to use the rudder properly
before you fly a critical aircraft.
Try a Cub/Citabria with barn door ailerons, you WILL learn
about the rudder! :)
We played with an Aeronca Champ one day, (full size) whatta
Shoving the stick hard to one side merely allowed you to view
the direction ahead out the side window!
You have to LEAD rudder then aileron into the turn, and LEAD
rudder to recover..... (with the Champ)
I was demonstrating slow flight to a friend in our 172 last
week, 20 deg flap, airspeed (what we could read) was less than 40
knots, stall warning horn blaring, and doing gentle figure eights
WITH THE RUDDER ONLY. Touching the ailerons would have dropped a wing
I observe 3 of 4 modellers not using the aileron and
elevator correctly while taxing the aircraft in a wind.
If you are unfamiliar with the terms "dive away" or "climb
into" , (the wind, while taxing) then find a pilot who does and
have them show you , it can save an aircraft.
OK... rant off! :)
Gord, did I follow your thoughts correctly?
On 22 Feb 2005 17:01:30 -0800, Dan_Thomas firstname.lastname@example.org wrote:
I agree 100%, Dave. When I flew my first Dr. 1, I had trouble keeping
it straight on landings. It weathervanes terribly. I bought and
installed a gyro on the rudder. It never would respond fast enough or
with enough movement. After about 2 weeks, I took it off and learned
to fly the rudder. To those of you who don't know how to do this, try
it sometime. There's nothing prettier than a multi-wing plane
sideslipping against a crosswind on final.
Coordination is the key. Whatever rudder is required to keep the
airplane from skidding or slipping. Incidentally, using lots of rudder
to speed up the inside wing is a SLIP, not a SKID.
> I was demonstrating slow flight to a friend in >our 172 last
That's strange. I'm an full-scale instructor, been flying 172s and
182s and 185 and Champs and Citabrias and homebuilts for years, and we
teach coordinated turns in slow flight to avoid initiating a skid with
rudder only and asking for that spin. Right out of the official Flight
Training Manuals. We show students what happens in slow flight in a
Citabria when you skid it with rudder: it spins. And a 172 is so
forgiving you can pick up a dropping wing while in the stall.
>Try a Cub/Citabria with barn door ailerons, you >WILL learn
I just landed a few minutes ago from a brief check flight in one of our
Citabrias. Taildragger training is my specialty.
I must be missing quite a few replies/etc. Two newsgroups and neither is
doing a proper job. Oh well.
I never had a problem flying Citabria/Decathlons because I always treated
them as though they were very short coupled beasties that could be nasty if
you let your guard down. Once that was taken into consideration, they were
no more difficult to fly than anything else.
The trick to flying short coupled, conventional geared planes successfully
is to anticipate the needed input before it is needed and apply a little by
leading it just a little. Everything looks beautiful, proper and straight to
the casual observer, which leads them to believe that it did not require a
correction at all. Then when they try it - snap!
By George Dan, I think you nailed it ;) Too much rudder = skid, too little
= slip. A *little* over simplified cuz sometime you don't "step on the
ball" you just release some/all rudder pressure. More of us RC types should
learn that solo doesn't mean you are a pilot - it just means that the
instructor thinks you know enough to get out of trouble. At least that's how
it should be <s>. Solo is the beginning of a new learning process that
should last until they pry your hands off the stick <VBG>.
Ed <Dan_Thomas email@example.com> wrote in message
Conversation just after my 1st solo flight..... (full size)....
Instructor.. "How do you feel?
Instructor..... 'You should, 'cause you just earned the right to
learn how to fly"
I never forgot that!
On Wed, 23 Feb 2005 17:48:43 -0500, "Ed Forsythe"
Ummm.... it becomes a slip if you HOLD the rudder and not allow (or
help) the low wing rise to level....initially it is a yawing rotation
around the vertical axis that "speeds up" the low wing in this
example.If one holds the rudder and completes a "flat" turn, (wings
held leve)l, are you "skidding " around the turn? - or "slipping"
around the turn? ....I gotta think about it... :)
Correct...Co-ordinated flight is the most important skill here...
In my example, the use of the ailerons is avoided because it will drop
a wing, and the rudder is gently used to turn. I was almost into the
"reversed control" region of the flight envelope, WAY below what
would be normal "slow flight". My instructor taught to use the
rudder to keep wings level when approaching a stall, the ailerons
don't work very well anyway at that speed... except to drop a wing
Our 172 is the "M" model, with the larger leading edge radius..VERY
difficult to spin, but will!
My friends Citabria will do as you describe, but seems to take a lot
of rudder to spin from level.. takes a HARD shove of the rudder to
drop a wing, but it has to be well below normal "slow flight" before
the spin can be started this way.
Been a while, will try it next time up with him...
I have limited time in full size draggers, but most of my models are
Watch the ball next time you recover from a turn using just rudder.
It will swing toward the low wing, and therefore you have a slip.
Sloppy flying. At really low airspeeds you could cause the outside wing
to drop and roll over into a spin. Been there, demonstrated that. If
you can't use the ailerons to recover from a turn, you are WAY too
slow. Approach speed should be around 1.3 times stall speed, and on the
base leg it should be about 10 knots higher. Nowhere near
Nope. Get it into a 60 MPH glide, and start skidding it around a turn
using rudder and opposite aileron to keep the wing up. Keep the nose up
to keep the speed down. Tighten the turn some more and the wing will
flick down and there you have it. Better have lots of altitude. This is
the killer turn: base-to-final, a bit low, pilot has overshot runway
centerline and wants to tighten the turn but he know steep turns near
the ground are bad, so he holds the wing up with aileron and tries to
get it around with just rudder, holding the nose up to stretch the
glide, and one more Citabria and pilot are written off.
All of this points out why I try to land a bit hot.
Why? Because try as we might to assess the airspeed of the model, there are
vortices constantly parading around on the airfield. This is not the
exception, it is the rule.
Get the models nose into the wrong side of a vortice (wind rotating toward
the nose of the aircraft) and you have just decreased your airspeed by the
airspeed of the wind in the vortice. Generally, you cannot see its effect
until it is too late, if you are a bit too slow. Keep the airspeed a bit
above what is necessary and you will fly right through it before you can
become aware of its existence.
Ever see those little burbles that your model displays on approach? Whoot -
there it is...
I try to teach my student pilots to learn how to fly their models at speed
near the ground. I then teach them to do low, flat approaches, field
permitting, while carrying a bit of throttle. Yes, it makes them nervous at
first, that is normal. But after a while they become used to flying with
full control authority and they do not fear landing as much as they did when
they were attempting to land with the throttle all the way back and the nose
pointed downward, praying and hoping that the wind would not upset their
approach. You make your own luck in this hobby.
On 24 Feb 2005 07:25:18 -0800, Dan_Thomas firstname.lastname@example.org wrote:
Correct..but my suggestion is only to use rudder momentarily to avoid
a yaw into the turn due to adverse yaw produced by heavy application
of aileron to roll out of the turn...
You did not mention anything about OPPOSITE AILERON! OR keeping the
wing up! (until now)..
Agreed.. this would be a killer!
I understood your example to be rudder application only....
I never feared steep turns at any altitude. Co-ordinated, and at
adequate speed, they work just fine..
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