I have a Hanger 9 PT-19 with a Saito 150 in it . The plane is heavy but I don't think unmanageable so . It was designed for 120 .

It does one strange thing, maybe two , maybe they are the same .

I would appreciate any help anybody can offer .

When taking off ,just after it lifts off the ground , maybe two feet high , it drops the left wing . It requires a fast correction to avoid a disaster . No matter how fast I take off it will happen. I am not sure what would happen if I took off less steeply and with lower acceleration. But this little habit is quite bothersome.

It also has a version of the same thing upon landing . If you land too slowly it will stall - without warning and drop straight down . If I hit the gas quick enough it will drop the left wing and maybe start flying again or spiral in.

Now they way I get around it is too take off slowly with a long run - it is a tail dragger so if I am not careful with throttle it will nose over. And keep the speed up while landing.

Some of the people at my field say its the lack of right thrust in the engine. There is none that I can detect in it now.

Others say the plane is not lateral balanced and needs more weight in the right wing. I checked this and it seems balanced . Adding weight to the right wing does seem like reasonable solution.

It is a very attractive plane and supposed to be a military trainer so I would have expected it to have very predictable flight characteristics.

But it in current state it is not exactly a Sunday Flyer.

Your thoughts pls , ideas, questions all welcome

Dropping the left wing is due to torque and perhaps some Pfactor due to the usually higher angle of attack upon takeoff when flying still quite slowly. The guys are right and some right thrust would go a long ways towards reducing this. It's more noticable because you're using a larger engine than the plane was designed for. The smaller engine would do the same thing but not as strongly.

IF you were powering it in a scale manner where the power to weight ratios were the same for your model you'd be flying it with a .60 or .90. With that engine the model would have a far more accurate scale performance and these issues you're finding would be all but unnoticable. But since we modelers just LOVE to power our models with at least the power to weight ratio of such things as the P51 Mustangs it should be no surprise when our models act to some extent like the old WW2 fighters did with torque reaction and P factor from using larger than designed for props on the larger engines.

So try adding a bit of right thrust and that'll help. It may not make all of the issues go away but it's a start. As for the stall on landing you just need to fly it more attentively to avoid stalling the model. As you say and from your description it's heavier than ideal and along with the torque from the bigger engine you're getting exactly what this setup can be expected to do.

I've one in my hanger as well and consider it one of if not the best flying plane I've owned. Mine is powered with a 4 stroke 1.20 and flies it well without the wing drop you outline but it does suffer the landing issue you note.

I think the issue with this low wing design is that when it is balanced to fly the best, it is actually out of trim for no power landings. A head wind requires some power on and she will glide a little nose up but otherwise produce a good glide slope that maintains speed enough to avoid stalling. However, with no wind and power off, the glide slope is too shallow to keep speed and it will slow down and stall. The solution is to force a steeper glide slope for no power landings. I do that by using flapperons and I may have some elevator mix... its been too long ago now since setting it up but the setup produces a proper (steep enough) glide slope for no power.

I probably fly the plane only every other month and recently forgot to use flapperons with a no wind condition and like you, saw the plane stall in from a few feet up but fortunately suffered no damage as mine didn't drop a wing.

As to takeoffs...yes the drag of those very large wheels will force careful elevator control to keep from having the engine pull the nose over. Are you getting back off the elevator a little as soon as she breaks ground?

btw... this plane is the only I've owned that will do fantastic lumcevaks.... as many as four reverse tumbles that always please the spectators.

Take off with less acceleration and the sudden jink will vanish.

The airframe needs a bit of speed before it's flying better than the prop is flying. To get to the speed you need to do the acceleration on the ground before you horse it off. Watch pattern flyers sometime. They do a straight run right down the runway centerline. Looks sort of scale like. Their takeoffs are not just straight but really safe and easily repeatable.

How do they do it? Sensible use of the throttle. The first part of the takeoff roll is where you very slowly add throttle. The "very slowly" part is the important technique. You taxi the plane out, right and it steers ok. So "taxi it" a bit faster on the start of the roll and it'll steer straight and build up speed on it's own. There will be a very short bit where you might have to make a correction or two, but if you haven't slapped on too much throttle too soon the prop won't have the torque or p-effect to win the airframe/prop fight. And as soon as the airframe is flying, the prop won't ever win.

Tower has a line of very small WWI biplanes. They're all very evil handling on the ground. But they'll all takeoff with almost no sweat when you get the hang of how gently to click the throttle on the start of the takeoff roll. Unless your gear is so screwed up the PT-19 won't taxi straight, it'll take off no sweat too.