Hi everyone, I'm trying to build a boat plane, influenced by many WWII craft. Generally, these have propellers hung just under the wings, which sit high and directly above the cabin, forward of the center of the plane.
Problem is, every time I try to fly something with this general configuration, the engines pull the top of the plane down to the ground/into the water. I got it to take off form the ground a couple times, but as soon as I let go of the elevators it started flipping over and crashing.
My question is this: How do I balance the plane so that the high-mounted engines do not pull the plane's nose down so dramatically? If possible, could someone explain to me how the real boat planes managed it?
u can try to have a heavy tail to pull that tail down while the high mounted props want to push your head down
@dsr1aviation thanks dude. It was funny after I posted the comment I figured it out . Typical. But I'm building a new one of my aircraft anyway. Thanks for responding though
@Mrloominati mirror that could be the issue. Some times it dupes the parts on 1 side. Try mirror the othe sode and the mirror normal again. That might help.
I have 1 question. I created a P61-A black widow over 3 days and it was always balanced and never usually ever ever have problems with COL or any thing like that I usually figure it out myself and fix it, but just before I was about to upload it I took it for a test flight for any last problems if there were any, and here is the problem. When I pitch the aircraft upwards it veers of to the left really violently. I checked the COM COT AND COL and the COL if off centre. So if I'm behind the aircraft the COL line is sitting slightly on the right hand side by maybe 1 block length or something. Plz help. The plane is perfectly mirrored but apparently the COL is off centre?????@dsr1aviation
@ClassicRocker69 just smash some weight into the back of the plane is the nose keeps having a mind of its own. Experiment with the weight and also one more thing. Check if the front end has too much fuel In it because fuel adds weight too. Play around with weight and u will soon have a plane that bows down too u and u have full control over.
@Sirstupid CoT is usually not an issue unless it's really far above or below the CoM, but unfortunately that's exactly what happens on designs like what Classic is talking about.
A low CoM is best for stability. CoL should be just above and behind it. Don't worry about CoT too much.
Thanks for all the help guys. I experimented with raising the CoM up to where the CoT was, but I got sort of a pendulum effect when I tried to steer the plane in the air. I'm going to try a couple things today to repair it, probably making the wings larger and mounting the props further back behind them. If I don't get it, I'll happily send it to you guys to try and work out yourselves :) Thanks again!
Center of lift should usually be a ways behind your center of mass. There's a few reasons for this, but it mostly boils down to making the plane more stable.
However top mounted engines change the dynamic a bit. Perhaps moving the CoL forwards will help counteract the off-center CoT
These planes are very tricky to balance, and you're totally right about the high engines being responsible. If you can fit a trim surface on (like mounting the horizontal stabilisers on rotators), that can help counter it. I'm fairly sure that's how they did it in real life. If that isn't an option, I can give it a shot, I got a similar plane by Cedy117 flying with a little XML editing. dsr1aviation is a great builder, though, and no offence will be taken if you send it to him/her first!
I would need to look at your build to better understand the problem it could be as simple as CoM and CoL too close or too far apart. It could also need some small blocks placed high in the build that can adjust the CoM upward. Hope this help if not upload privately and tag me in it and i will try working it out :) good luck