HELP MY PLANE KEEPS PITCHING DOWN

[Yoyohay]

I built a P-39 but it keeps pitching down, even though the Center of Mass is in the middle of the wings and there are a bunch of wing sections in the wing so there is plenty of lift.

Here is my plane if anyone can see if they can help: https://steamcommunity.com/sharedfiles/filedetails/?id=2654083998

[Yoyohay]

Could the engine not have enough power?

[Yoyohay]

It is not that, I changed the engine to have way more cylinders and it still pitches down.

[BadlyCroppedFish]

Center of mass may be in the middle but the "center of lift" if that is even a thing, is probably not. Might need more or less wings on front or back, or just add trim to the elevators like planes do irl to prevent pitching

[Yoyohay]

Originally posted by BadlyCroppedFish:

Center of mass may be in the middle but the "center of lift" if that is even a thing, is probably not. Might need more or less wings on front or back, or just add trim to the elevators like planes do irl to prevent pitching

Ok cool I will try that, thanks for the help

[Eagle]

Ok so I looked at this and was in the process of trying out some changes to the model and the engine suddenly decided not to crank up anymore. Ill have to figure out what it is I had accidentally deleted but youve got several issues going on.

One is that your wings are way too far back and too far forwards theres too much wing area and its causing it to do flips. Theres also something wrong with your Microcontroller setup because it pulls to the left for roll is very difficult to counter.

Also your Aircraft prop is set Positive already and it should be set to neutral.
You dont want your plane to take off or move simply because the engine starts so you need to have a number output going into the prop to control that.

So the wings I took and redesigned to have much more cut trhough the air and lift under them. You Horizontal Stabilzers were up about 1 block too high.

Your landing gear were extremely far back. Your COM is sure center alright but thats the problem you dont want your COM Center of the Aircraft itself but Balanced usually just forward of the pilot seat over the pilot seat or just behind it. Somewhere in there NOT in the center of the fuselage that is what is causing your flips.

You picked a model that has its own issues being that the engines on most planes are in the nose and this ones is center. Your nose is a tad too short by about 2 blocks as well.
I moved your Battery into the nose area to help with the balance issue.

After moving the landing gear to the center of under the wings I saw that the weight needed for the nose to tip forward was quite great. Adding several weight blocks to the nose area just barely made the tip forward.

Also you are using control surfaces. They are weighty themselves and in my own opinion are much too large for this smaller plane.

Main thing is your wings are massive have a look at the aircobra youll see your wings are way too big and wide. Your nose is a bit too short I think and its causing a weight issue.
After adjusting the wings and landing gear the issue was the nose not going forward enough and the landing gear being too far forwards and the nose being in the air on spawn and like I said weight blocks just barely solved that tip forward and then suddenly your plane didnt want to actually go anywhere lol.

I think its the weight and you also dont have a clutch or gear box on your engine. I have one on my cessna and that is what got me off the ground with teh addition of control of the prop pitch via a number input.

[Eagle]

So without making any changes to the Fuselage I added two gear boxes arrows pointing away from the engine set the ratios to 3:2 and no more nose pitching down
But you have an issue with your controller somewhere because there is no roll left and stabilization does not give you the ability to roll left either.

[Yoyohay]

Originally posted by Eaglezero6205:

So without making any changes to the Fuselage I added two gear boxes arrows pointing away from the engine set the ratios to 3:2 and no more nose pitching down
But you have an issue with your controller somewhere because there is no roll left and stabilization does not give you the ability to roll left either.

Ok, cool thanks. Yeah the sabilization broke in the version I linked here, but I fixed it

[Yoyohay]

Originally posted by Eaglezero6205:

Ok so I looked at this and was in the process of trying out some changes to the model and the engine suddenly decided not to crank up anymore. Ill have to figure out what it is I had accidentally deleted but youve got several issues going on.

One is that your wings are way too far back and too far forwards theres too much wing area and its causing it to do flips. Theres also something wrong with your Microcontroller setup because it pulls to the left for roll is very difficult to counter.

Also your Aircraft prop is set Positive already and it should be set to neutral.
You dont want your plane to take off or move simply because the engine starts so you need to have a number output going into the prop to control that.

So the wings I took and redesigned to have much more cut trhough the air and lift under them. You Horizontal Stabilzers were up about 1 block too high.

Your landing gear were extremely far back. Your COM is sure center alright but thats the problem you dont want your COM Center of the Aircraft itself but Balanced usually just forward of the pilot seat over the pilot seat or just behind it. Somewhere in there NOT in the center of the fuselage that is what is causing your flips.

You picked a model that has its own issues being that the engines on most planes are in the nose and this ones is center. Your nose is a tad too short by about 2 blocks as well.
I moved your Battery into the nose area to help with the balance issue.

After moving the landing gear to the center of under the wings I saw that the weight needed for the nose to tip forward was quite great. Adding several weight blocks to the nose area just barely made the tip forward.

Also you are using control surfaces. They are weighty themselves and in my own opinion are much too large for this smaller plane.

Main thing is your wings are massive have a look at the aircobra youll see your wings are way too big and wide. Your nose is a bit too short I think and its causing a weight issue.
After adjusting the wings and landing gear the issue was the nose not going forward enough and the landing gear being too far forwards and the nose being in the air on spawn and like I said weight blocks just barely solved that tip forward and then suddenly your plane didnt want to actually go anywhere lol.

I think its the weight and you also dont have a clutch or gear box on your engine. I have one on my cessna and that is what got me off the ground with teh addition of control of the prop pitch via a number input.

Alright, I'm pretty new to making planes in stormworks, I'm more of a land vehicle guy but thanks for the input. I do have a clutch and I did not know the COM was supposed to be over the cockpit, I was always told it should be in the center of your wings. I will work on fixing the issues you mentioned but overall I think it's best if I stick to the ground.

[ElfBossHogg]

One other thing to consider is that the CoM in the build screen doesn't account for the weight of the fuel when loaded. As a result you will need to adjust their placement by trial and error in order to get the best balance.

Additionally you should consider how the fuel will empty so that your structure won't become too unbalanced as fuel is used. For example if you have all your tanks in the rear as they empty the nose will become more dominant and pitch down.