Swap Meet Balsa Find, Hangar 9 P-47 Thunderbolt

[PsyBorg]

Your fuel lines are not maybe a tad too lng and the clunker got hung up while you were maybe inverted did it? That is usually the case with a presurized fuel system. The clunker is too light or gets hung up on the sides of the tank and catch air. Had that happen on my franken truck when it was still a buggy in its original state after a roll over. If it rolled right it was fine. If it rolled left the line would hang about mid tank along the side and immediately suck air and stall.

 

[Joker 53150]

It's certainly worth checking out and easily done. Usually when I set them up I try and get the clunk close to the back wall of the tank without actually touching it so it's got freedom of movement.

 

[Buttered Cat]

Hi Joker,
I'm doing a similar thing to you, having bought an old P-47 and now getting it flight-ready. The only difference being, mine will be electric.
But in order to choose the right motor/battery set-up I first need to know where the CG should be. There is a couple of marks on the underside, the tell-tail signs of where the previous owner had the CG, but it looks too far forward to me.
Where is your CG?

 

[Joker 53150]

Quite honestly, I have no idea! I had to add a bunch of weight to the nose to get it to balance, but have since pulled the engine. There were no marks on mine, I went off of what I found online in the manual.

 

[OliverW]

Hi Joker,
I'm doing a similar thing to you, having bought an old P-47 and now getting it flight-ready. The only difference being, mine will be electric.
But in order to choose the right motor/battery set-up I first need to know where the CG should be. There is a couple of marks on the underside, the tell-tail signs of where the previous owner had the CG, but it looks too far forward to me.
Where is your CG?

I say when in doubt, make it a bit nose heavy!

 

[TooJung2Die]

There is a couple of marks on the underside, the tell-tail signs of where the previous owner had the CG, but it looks too far forward to me.

In my job, when I see something odd that was put there by another engineer, I stop and think before changing it. It was made that way for a reason and it may have taken them a long time to figure it out. The previous owner probably put the CG marks there for a good reason and it took them some time to find the right spot.

 

[Joker 53150]

In my job, when I see something odd that was put there by another engineer, I stop and think before changing it. It was made that way for a reason and it may have taken them a long time to figure it out. The previous owner probably put the CG marks there for a good reason and it took them some time to find the right spot.

Then again, maybe the other guy was an ax-murderer. I know when I got my P-47 it needed a lot of weight in the nose to balance at the spot shown in the instructions. It really makes me wonder how he flew it so tail-heavy.

 

[Buttered Cat]

I say when in doubt, make it a bit nose heavy!

Certainly wise words. But as Joker pointed out, it's going to need some extra weight in the nose. (I've read that elsewhere too!).
But seeing as I don't have a motor or battery yet I figure why not go for a bigger motor and bigger battery and make that extra weight do some of the work!
But to do that I need to have a fairly accurate idea as to where the CG should be. If I follow the marks already on the plane and they turn out to be too far forward (as I suspect) that will then mean adding weight in the tail because I've got too heavy components in the nose.
But of course if I get it wrong the other way I'll be adding weight in the nose whilst thinking "I wish I'd bought a bigger motor!".