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Old Mar 25, 2003, 03:45 PM
Atlanta
Joined Jun 2002
776 Posts
what is it that you have to take care of when flying a warbird?

I see many threads over here, and outside this forum complaining of troubles flying P-51. I have been able to fly successfully

but I just wanted to know what makes the warbird different than the high wing trainer. Not to forget the control setup, something that you should check prior to flying, inflight, and landing.

Crashes do happen, everyone crashes, but if someone crashes because of the above reasons then they should be guided
any help regarding on this topic will greatly be appreciated

I may be the next victim,

thanks
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Old Mar 25, 2003, 04:01 PM
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Minneapolis MN
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My guess would be:
1) higher wing loading due to scale wing with less wing area
2) tapered wing makes it easier to tip stall
3) Scale body(shorter) makes CG more picky, more pitch sensitive
My .02 cents.
-Sam
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Old Mar 25, 2003, 04:02 PM
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I've noticed that mine is really tweaky in two respects:
The control surfaces don't fully return to the neutral position.
The amount of required throw is inconsistent.

I don't know if these are the fault of the plane, or how I built it. Whatever the reason, it makes it extremely difficult to trim.
On one pass, I'll need to add some up & right, whereas on the next, I'll need to add more right, but no up ??? Needless to say, it makes for a very frustrating experience.
I've tip stalled twice into a death spiral and planted it. This, I'm sure, is just inexperience though...

edit: I just remembered: One thing I did notice when I opened up the package was the fuselage looked like it was bent when looking down it lengthwise - kind of 'banana-like'. This might be by design, however.
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Old Mar 25, 2003, 04:08 PM
Captain Carnage says......
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Also the main weight of the plane tends to sit on top of the wing as well. While high wing trainers have the weight on the underside to act as a pendulum now you have it on top still a pendulum, but above the wing....guess where it really wants to be....yup on the underside.)

the basic design of low wing warbirds is for manueverability and speed, thus the reasons mentioned by FlyingwingFan are the outcome of the design.

Chuck
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Old Mar 25, 2003, 04:15 PM
Atlanta
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tip stall, does this happen when landing or inflight? I usually land with some power.
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Old Mar 25, 2003, 04:22 PM
Atlanta
Joined Jun 2002
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Thats weird I have never noticed any tip stalls, but my megastealth tip stalls when I throttle fully down. P51-D doesnt show any tendency of doing that, Maybe ill try throttling fully down next time to see whether it does it.

does tip stall happen because of lack of speed?
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Old Mar 25, 2003, 04:27 PM
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Tip stalls in landing, carries on the AUW of your plane, and wing incident..

I noticed this tendency on my P-51 Python. Where it carries a heavy load, and the wings are small, as well, as smaller airfoil.
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Old Mar 25, 2003, 04:31 PM
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It's easy to tip stall the Mustang. Just fly level and see how much you can slow down. At some point, the plane is going to sorta lunge to the left or right while spiraling downward. Presto, tip stall.
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Old Mar 25, 2003, 05:53 PM
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The main difference with Warbirds is that you must keep your speed high. I use a propeller battery motor combination that gives me a flying speed of 2.5 times stall speed. I fly full throttle until I want to land. When I wish to land I cut the throttle to 1/3 and my landing approach is one great big gentle sweeping turn, straightening up at about 10 ft high. This keeps the speed up. At 1 ft of the ground I cut the throttle completely. I have no troubles with tip stalling because I never fly a Warbird slowly.

Ken
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Old Mar 25, 2003, 06:13 PM
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Milwaukee Wisconsin, United States
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Kensp has it right here, keeping speed up and minimizing high G's especially when going slow are the key.

I've got a jk aerotech p-51, about exactly the same size and area as the gws one but scales in at 41 oz one the sp500 motor and 7 sub C's, putting wing loading at around 24 oz/sq ft.

It flies very scale like as you might expect, and fast, but flying it is'nt really too hard as long as you:

A. keep the speed up. Stall speed is high, and you have to stay comfortably above stall speed.

B. Never suddenly pull up hard. ( instant high speed tip stall and roll to inverted! )

C. when going slow onto final, turn gently, minimizing the speed differential between the inside and outside wingtips, and the load the wings must support.

BTW, a low wings planes " tippiness" is largerly mitigated by having the proper amount of dihedral, shifting the center of lift much higher on the fusalge. My p-51 is genuinely stable. You can easily envison how the real 1:1 scale p-51's were considered to be stable gun platforms.


Dean in Milwaukee
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Old Mar 25, 2003, 06:34 PM
Hey... watch this...
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>>>>>>>>
Thats weird I have never noticed any tip stalls, but my megastealth tip stalls when I throttle fully down. P51-D doesnt show any tendency of doing that, Maybe ill try throttling fully down next time to see whether it does it.

does tip stall happen because of lack of speed?
>>>>>>>

Well first a little background forgive me if you already know this..

A stall (in general) happens when there is not enough airflow over the lifting surface of the wing. Wings lift by developing low pressure above the curve in thier airfoil. This low pressure is created by air movement along the wing area, the wind flowing across the rise in the wing (its lifing point) has to speed up to keep pace with the wind around it. This "speeding up" of the air over that point in the wing creates low pressure that begins to "pull" up on the wing below it.

Because the low pressure above the wing has to lift the whole plane with it (because the plane is attached) thier needs to be sufficient low pressure to overcome the entire model wieght. This requires a certain amount of air flowing across the area in a given amount of time to achieve flight as we know it.

There are 2 ways to stall the lift area of the wing.

The first is to slow down so much that the required amount of airflow across the wing decreases to the point that the low pressure can no longer hold the model in the air. This is called a "low speed stall" and generally the plan drops drastically when it happens. These stalls are recovered from by adding power or trading altitude for speed to get the airflow moving.

The second is to be at high speed and with enough airflow over the wing but the plane pitches upward (nose up) so much that the airflow is effectively blocked from going across the wing and
the model stalls nose high, most of the time the plane does not drop but it will not respond very well to roll and up pitch commands, this can also lead to the dreaded spin but thats another story. This is called a "high speed stall" and is recovered by lowering the angle of the upward nose to allow the air to pass over the wing again so simply release the back stick and it should come right out if you act fast enough!

Now in knowing the above, either situation can create a tip stall. A tip stall is a traditional stall from the definitions above but we have to remember that planes have 2 wings... hence 2 lifting surfaces and both dont always stall at the same time!

So when only 1 wing stalls and the other is still creating lift the plane "tips" over onto the wing that stalled. This tipping can be very drastic and voilent at times leaving no time to react.

This is what most warbids are prone to and why most add alot of nose wieght to counter this from happening some of the times but no matter what if you "ham" fist a plane around enough things go wrong very fast!

And no I am not an expert... but I did stay at a holiday inn express last night!





Mike
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Old Mar 25, 2003, 08:52 PM
D W
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what is it that you have to take care of when flying a warbird?

Your six. ALWAYS check your six.
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Old Mar 25, 2003, 10:10 PM
IAMCANADIAN
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Canada, BC, Squamish
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off topic - sort of

mmarshall, who's still teaching that bunk about the air over the top of the wing going faster than the air over the bottom!?!?
Simply doesn't make sense when you think about it. Everything else you say is correct. A flat plate will generate lift if held at an angle to an airflow. This is called Angle of Attack and its what creates lift. Next time your hanlding a sheet of plywood in the wind you immediatly understand how lift is created. The shape of the wing does many things including: determine efficiency (lift vs drag), pitching moment, and stall charactaristics. It does not force the air over the top to try to 'catch up' with the air under the bottom.

A tapered wing is more prone to tip stall because a narrower cord tends to stall easier than a wide one. Narrow tips are used because they create smaller vorticies and thus less drag.

Didn't stay at a Holiday Inn recently but I read everything I can get my hands on about aerodynamics.
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Old Mar 25, 2003, 10:11 PM
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back on topic

Quote:
what is it that you have to take care of when flying a warbird?
uh... your wingman?!
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Old Mar 25, 2003, 10:23 PM
Atlanta
Joined Jun 2002
776 Posts
ok I get the idea, too much or too less speed will tip stall the plane. But that goes same for high wing planes isn't it?

What am i talking I have been successful with my P51-D. Lucky for me even not knowing i was still able to fly without crashing. Now that I know, I hope I dont crash it because of the fear of tip stalling
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