P-51 and Tip Stalls

Call it what you like but when "tip stall" is mentioned, virtually everyone knows the cause and result.

Reply to
Paul McIntosh
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Yes, improper piloting technique.

TAS

Reply to
The Amazing Seismo

AND the design of the airframe. But keep believing what you want to believe...there have been MANY full sized aircraft that had vicious tip stall tendencies. The worst I recall would never snap the same way twice...

Reply to
Keith Schiffner

Whcih one would that be?

Dan

Reply to
Dan_Thomas_nospam

Yes, poor design can exagerate the phenomenon immensely.

So can overloading a wonderful design with too heavy of a finish, too many weighty gee-gaws, too much reinforcement, etc.

Ed Cregger TAS

Reply to
The Amazing Seismo

But, TIP STALLING doesn't exist! ;^)

Reply to
Paul McIntosh

It's been EONS(well seems like it) since I was reading up on the various aircraft. IIRC it was either a German or British fighter from WWI(phase

2) or WWII.

Been year like I said but I do recall some of the pilot complaints about that.

Reply to
Keith Schiffner

Most likely some WWI airplanes. Some of them were notoriously flexible, and the wings could twist somewhat with various loadings and cause trouble. Many of the designs of that day were also tail-lifting types, with the CG behind the center of lift, a feature that has been illegal in any airplane for many, many years now, since it makes stall or spin recovery nearly impossible. I have seen some models with pretty flexible structures. They must be a bear to fly, and would also be prone to flutter. Dan

Reply to
Dan_Thomas_nospam

Sorry about that...a subtle point of humour. A few of us consider WWII to merely be a continuation of hostilities carried over from WWI. Pretty accurate imo.

As for the airframe I'm certain it was WWII and at further thought pretty sure it was German...possibly the 109. But like I said it's been eons.

Reply to
Keith Schiffner

Aye. A paradox, it is!

TAS

Reply to
The Amazing Seismo

I do believe that this is the longest thread I have seen that both stays on topic and doesn't degenerate into name calling!! We CAN do it if we try!!!

BTW, the Cherokee 140s I used to fly had washout built into them as well. If I recall correctly it was uneven too. 3 degrees on the port wing and 2 on the starboard. Or was it the other way around?? For my 2 cents, I think that "tip stall" is a description of the event that full scale folks call the stall/spin/crash. It's the rose by any other name thing, it still stinks and the results are the same. We were taught to keep the airspeed up by about 10kts when landing in gusty winds. Higher if the gusts exceeded 15-20 kts or so. All this to prevent the stall/spin/crash. The same holds true in RC. Maintain thy airspeed lest the ground rise up and smite thee. :)

Jim W

Reply to
Black Cloud

We were taught to keep the airspeed up by about 10kts when landing in gusty

Yet all the R/C "manuals" and "experts" teach having the throttle almost down to tick over during the landing approach.

Malcolm

Reply to
Malcolm Fisher

Throttle is not required to maintain airspeed under ALL conditions. A proper nose down attitude will do quite nicely as well. Otherwise, how do you perform a dead stick approach?

Reply to
Chuck Jones

Granted.

I have no problems with dead stick as I learned to fly with gliders where every landing is dead stick and only on some slopes can you overshoot and try again.

I feel that a "power on" approach is best when flying planes with a fan on the front end.

Malcolm

Reply to
Malcolm Fisher

The only thing the propeller is for is to keep the pilot cool. Mine quit one time and boy, did I ever sweat! Gord Schindler MAAC6694

Reply to
Gord Schindler

Adequate speed is the key, as you say. But steep turns in the base-to-final can kill. Remember that the stall speed rises in a turn, by the square root of the load factor. In a 45 degree bank the load factor is 1.41 and the stall rises by about 1.2; if the pilot's a little slow, at or under the recommended 1.3 times stall, he's playing with fire. In a 60 degree bank the stall rises by 1.4 times stall, a sure killer at low altitude and low speed. In both situations, descending turns, the low wing will drop first and the airplane will roll over out of control. This is why the pilot tries to avoid steep turns in the circuit; 30 degrees is acceptable. Skidding around the turn seems to be an intuitive reaction when overshooting runway centerline, but it's the wrong reaction.

Dan

Reply to
Dan_Thomas_nospam

I see that no one has posted here since March but here goes m

question.

I've been flying the GWS P51 for 5, 20+ minute flights. She's wel trimmed and flies great. I've cut the motor out at 200+ feet and glide down to 20' above deck, powered up and have had no issues with it. I glides fairly well. Here's the question. I was flying the other day i almost calm conditions I was level and full throttle (brushless 11.1

1500ma 8060 prop 10 to 11amps static) when all of the sudden she flipped upsided down in a very quick snap. recovered and continued on with no other surprises. On the next flight again I was level full throttle and she did a snap roll so fast we wer all amazed, I would have liked to take credit for such a nice manuve but I didn't do it. She snapped rolled so perfect she ended back u level and on same heading. Could this have been a Tip Stall. Keep i mind she was level with no inputs from me.

Car

-- Carl

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Reply to
CarlP

If that's what you're seein', it's unlikely you'll see any answers, but here goes, anyway.

No, at speed with no Gs being pulled, it wouldn't be a stall of any kind. Radio/servo interference or malfunction would be more likely (not saying that's what it was, just what it could have been). You didn't see any of your buddies off to one side snickering and hiding one of those transmitters with "one button snap roll" on your channel, did you?

Reply to
Noah Little

maybe the wings are not tiff enough at high speeds and bende a bit. ?

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Reply to
Dingo

Carl, There are several possibilities here. And as mentioned by Noah, there is the possibility of radio interference - I had the same thing happen with model a long time ago but it was only in a very specific area and only affected one channel (throttle). Very strange. I will add that when I was holding the plane, there was NO problem. It only showed up when I walked away. Apparently my body was blocking the interference some how. I have other bad habits as well....

I would think a tip stall unlikely in straight and level flight so I think you should look elsewhere for a solution.

I'm not familiar with your specific model but another possibility could be the way the wing is mounted. How are wings held on? I've seen this before with wings that are held on with rubber bands, where there were not enough bands used. When the plane gets to a certain speed, the wing can start to separate from the fuse, causing all kinds of strange things to happen, none of them good. And, asDingo mentioned, the wings may be flexing at high speed and causing problems.

I would also suggest you check your flight controls for security. I watched a model do some uncommanded maneuvers and then crash. It turned out the builder had epoxied the elevon hinges in with 30 minute epoxy, which allowed the epoxy to be almost completely absorbed into the wood, allowing the hinges to loosen easily.

Range check your radio carefully with the engine both off and on and then check everything else very closely before you fly again or you may risk losing your plane.

Good luck and let us know what you find. Cheers, jc

Reply to
jc

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