*Crash*Johnson*

My Feedback: (7)

I have finally (about 6 months) gotten my Spit flying... What a journey. Engine issues, balance issues, ect ect... Anyway finally got it up in the air and it's odd....

If I bank it left and pull hard up elevator, it ~snaps~. Meaning: When I go full up elevator, it pulls a bit then snaps right (rolling over). Not too bad when ya have it up 200' and are expecting it, but when your 50' over terra firma it's frightening. I noticed the engine has a lot of right thrust in the firewall (sitting in the cockpit it goes right, I would assume that's right thrust).
Would this be the culprit? Is this common on warbirds, or Spit's in general?

Ruudje

Hi,

maybe your CG is too far aft.
It can also be a high speed snap. Too much speed combined with too much up elevator causes one wing to drop. Less elevator would then be the only remedy...

*Crash*Johnson*

My Feedback: (7)

I assume "aft" is tail heavy? Not possible, and if it is I am going to light the plane on fire and bury the ashes. I put a OS-FL70 four stroke on it and it took 16 oz to balance it where the manual said. So I took the engine off and replaced with a RCV 90 (added the 16oz I was looking for, and don't believe in adding dead weight...)

SpitfireMKI

My Feedback: (2)

Ease up on that elevator chap, Ruudje is on track ! The only time you should be heavy into the elevator is when you flare.

S1

Pete850

Full up elevator + X = snap

Where X = warbird (and probably most planes come to think of it..........)

Cut your elevator throw right down and add 60% exponential. These birds are not sports planes or 3D'ers. Just be gentle with the controls and you'll be fine.

*Crash*Johnson*

My Feedback: (7)

The throw is set to the manual. Not much in there at all. Aint even used high rates on it. I was just mostly wondering if this was normal and if it's what they refer to as a "high speed snap".

It's not a bad flyer really, and I don't fly it like a 3-d plane (they're ok, just aint my thing [Read: I can't do the maneuvers])

Thanks for the advice guys!

nmacwarbirds

Dear Crash Johnson
Spitfires need to be guided not forced around the sky.
My Spitfire has plenty of movement on all controls, so you need to fly these warbirds
gently and smoothly with rudder in the turns so the turns are in balance.
Regards Phil G.

Tommy_Gun

As others posted above it does sound like too much elevator throw and possibly and AFT CofG.
Although if it IS balanced too nose heavy, the amount of elevator required to try and hold the nose up at low speed could cause an accelerated stall.
In recent model magazine articles the proper flight test methods have been illustrated to help you to determine how to make your plane fly better. They show how to check for proper CofG and engine thrust and decalage. Using those methods may be of some help for your Spitty.

I would also suggest that before you go and use the computer radio to adjust the response of any surface.
That you FIRST adjust the mechanical linkages to get as you can to the desired results. THEN use the convenience of Expo and Dual Rates.

F4u5

My Feedback: (81)

You could have a warped wing...check the washout in both to see if they are close.

*Crash*Johnson*

My Feedback: (7)

How would I go about checking that? I have an incidence meter, but aint taken it out of the box. It's one of them tools I forgot I have... Mostly bought it cause I found out you can use it to check heli pitches.

F4u5

My Feedback: (81)

You could use an incidence meter on the outer wing, but I have never used one. I usually just eyeball it or lay the wing on a flat surface and take measurements.

luc-RCU

well, I got the WM spit but never managed to have a nice flight with her. Seemed tail heavy, even if CG was as mentioned.
Retract supports collapsed on a landing not that strong. I gave this plane away...
The H9 warbirds fly much better and I never got retract attachment problems (though retracts are weaker)

SpitfireMKI

My Feedback: (2)

Satisfy my curiousity, Are you just yanking back hard on the elevator expecting it to respond ?

*Crash*Johnson*

My Feedback: (7)

Perhaps my first post wasn't clear enough.

When I fly her, I go easy into the turns, kinda like it's a Zagi. Coordinate the rudder and ailerons and bank it soft and bring it around. I tried to do an S turn (I think that's the maneuver... Go inverted and up elevator to bring it around) and it snapped. It'll fly ok if I go easy on it, but I was just wondering what would cause this. Eliptical wing? Right thrust on the engine?

LUC, I hear ya about the CG. The manual had 110mm first, then amended it to 105mm. I could get the 110 easily with a FL-70 4s. It flew REAL squirrley, so to get the 105mm I had to add 16oz of engine. Seems to fly ok now, feels a bit heavy but adding a pound of weight will do that.

SpitfireMKI

My Feedback: (2)

Ok, Up elevator refers to nose up, which would be pulling back on the stick, full down or nose down would be pushing forward on the stick.

If inverted, you push forward on the stick to maintain level inverted flight. First you will notice that you must fly at a higher angle of attack to maintain level flight, our "semi symetrical" airfoils are designed to be more efficent right side up. Therefore, your stall speed inverted is higher, now throw in nose heavy, and too much elevator and the wing will no longer want to fly.

This is not a spitfire trait, although every spit I have flown has always been elevator sensitive, that long tail makes a great lever.

S1

SBR_RV

dude what do u expect, its a warbird[&:]

*Crash*Johnson*

My Feedback: (7)

I know, thats what I am wondering, if I should be expecting this. I didn't think for a second it would hover and float in easily.

Richard L.

My Feedback: (24)

Mine doesn't snap. However, I rarely use full/abrupt elevator and the plane is balanced slightly nose heavy. Use smooth and gradual stick movement when flying any warbird. With full 45-degree flaps, the plane floats in for a landing at a slow pace.



Stock retracts held up fine after 60 flights without any issues.

*Crash*Johnson*

My Feedback: (7)

I got about 10 on mine and the retracts seem to be holding up well. Where's your's balancing at? 105mm right?

Richard L.

My Feedback: (24)

Yes, it's balanced at 105mm.

*Crash*Johnson*

My Feedback: (7)

What engine and or how much weight did it take you to balance it? I'm thinking 16oz was way too much to balance it, and thinking I did something wrong.

Richard L.

My Feedback: (24)

Actually, I think I balanced the plane at 102mm. I have a YS 91FZ in the nose and had to add one ounce of lead to the engine mount.

flycatch

My Feedback: (26)

Several years ago the publication "Model Airplane News" did a kit review on the Top Flite Spitfire. It suffered from the same problems you are encountering. I suggest you research this article, it may help.

SpitfireMKI

My Feedback: (2)

16 ounces does sound like a bunch for that plane, especially if Richard is using only one ounce. That would go back to what I was pointing out with inverted flight.

S1

captjack

My Feedback: (3)

What you have is a high speed stall brought about by the application of too much elevator.the resulting snap is the result of the stall.least you know what to expect now and it is predictable.to try and eliminte this trait decrease the elevator throw and try it again,keep decreasing the throw till this tenency goes away.a decrease in as little of 1/16 inch could make the difference.easist way is to move the elevator clevis a hole or two furter away from the elevator.you may find that your plane may be a tad noseheavy.a tail heavy plane is really sensitive to elevator,to the point you barely move the stick and it does the roller coaster ride.