What are these?

Modeling Subjects Aircraft
1

What are these, What do they do? And can you get them after market?

Thanks

2

They are the mass balancers. Not sure about aftermarket. Should be easy enough to scratch though

3

I can’t say I have ever come across them as AM parts, but john is right, they are pretty easy to make, I have had to do the odd one when the carpet monster has had them away.

4

I don’t even know where to start in making them.

Thanks guys

5

What scale are you doing, and have you lost one or does the kit not include them.

6

48 scale It’s the Academy kit and yea I lost one

7

Which I guess means you have another to copy. It’s a bit different in shape to the German ones I am used to. Assuming the kit one is accurate, I would go for some styrene strip, the same width as the support of the balance. Glue a couple of pieces together until the thickness is right, then sand the front and back to a sharp edge. For the actual weight, I would go for styrene rod rounded off at the front end and the rear sanded to a finer point.

I know it sounds awkward, but honestly its not as bad as it sounds.

8

Actually they are a very common aftermarket part, but…

all the ones I’ve ever seen were photo etched brass, and not at all accurate.

I’d copy the one you have and put the copy on the bottom.

9

Stretched sprue can help in making one.

10

Ken,

If you’re not scratch building them, I can probably send you a pair from the old Revell P-38J kit. I have it and the Hasegawa kit, so it’s not like I don’t have examples to go by if I want to scratch build them.

Others can say whether the balancers on the Revell kit are okay are not. They look fine to me.

Here’s an example of what they look like on the model.

http://cs.finescale.com/fsm/m/online/1579791.aspx

Gary

11

Gary, Thank you and thanks to everyone for thier suggestions.

Gary, Do you still have my address

Everything I’ve tried to scratch build comes out looking like bad. A good comparion would be paintings

I’m the kindergarden painting then you have all the painting master peices like van gogh (sp)

12

Ken,

If it’s still the same, then yes.

I’ll drop them into the mail tomorrow.

Gary

13

Thank you Gary.

Another notch on the board of Gary helping me and no chance in the fore seeable furure of me helping gary or anyone else out. Oh Well someday it will

Yes, My address is still the same

14

You all know what will happen as soon as I get them from Gary. I’ll find the one I lost [8-|]

15

If my faulty memory is correct, weren’t they used in an attempt to solve a bad tail fluttering problem? I think people are still split between if it actually helped or not. I seem to recall that a good portion of the problem was solved when properly fitting leading edge fairings were added to the wing center sections where the wing met the fuselage pod.

I’ve also read where the mass balance on the top of the horizontal tail killed a pilot or two when they bailed out of their stricken craft. They would bail out through the top of the canopy only to be hit with the balance as they blew back in the slip stream.

Eric

16

You are correct, Eric. Kelly Johnson was convinced the Lightning didn’t need them, though. He had large fairings installed on the leading edges of the wing-fuselage joints to solve the fluttering problem. The elevator balances were installed at the same time (I believe the balances were an Army-suggested fix, and not suggested by Lockheed), and stayed on all production models of the Lightning. My source? The book “Warbirds Of WWII” by Jeffrey L. Ethell. He’s pretty darned knowledgeable on the Lightnings. Great book - I picked it up on sale a couple of weeks ago at Barnes & Noble for $10.

17

You guys are on the right track, buts by no means a problem unique to the P-38. Any time any control surface is deflected, the result is the creation of a low pressure area on the cambered side, and the desired effect is that the control surface rises into that area. But if the center of gravity of the control surface is behind the hinge, then just the control surface bends back up, which causes flutter.

In general, this problem is corrected by having a substantial portion of the control surface ahead of the hinge.

The same holds true for the rudder.

But by it’s nature, being trapped between the two booms, this design couldn’t be used.

For something like ailerons or rudders where the area of the movable control surface is small relative to the wing/ tail it’s not a big issue, but on the P-38 and P-61 it’s half or so of the horizontal stabilizer.

I hadn’t heard the idea of a pilot getting stuck by the thing though it’s certainly possible. But I’d take my chances on that over a tail. I know that on the P-61 the protocol would be to roll over upside down.