World Model P51 ?'s
 

Picked up last year a World Model P51 ARF and I'm getting ready for the build but had a couple questions. I read some of the reviews and went with the Saito 91 SGK engine but I also read that some guys suggest you glass the wing. Is it really necessary and if so a quick tip on how to get this done would help. I've only built 3 other planes, all ARF's, and could use some guidance. Also, read that it asks for high torque servo for the retracts but I have pretty good JR's with about 92oz of torque, is this enough?

Thanks!

RE: World Model P51 ?'s
 

is this the .40 or .60 arf? The servo's sound good for either. I had the .46 and it did not need the glass for the wings center, however you are using more motor than I did.

RE: World Model P51 ?'s
 

Thanks for the reply. It's the 40 and when I asked around at the field I found a couple guys with 101's and 110's in their's.

RE: World Model P51 ?'s
 

Ive built(assembled) a half-dozen or so of these for different people. We've put everything from a .46 all the way to Saito.91's,,,a few with OS61FX's. That seemed to be about the best combo going for a good balance of speed/sport flying. Matter of fact, I've got one on my bench that I'm restoring right now. A friend gave it to me a few years back, and I'm just getting to the point I can work on it.
As for glassing the center section...I can't say it's a bad idea, but it could end up being a bit of work. You'll have to cut away the covering VERY carefully so as not to cut, or even score the balsa underneath. Then peal it back, or remove it to lay in your glass on. Then obviously recover that area.
Honestly, Ive only glassed one...and it was one I DIDN'T build, but ended up repairing because the wing was SO pourly joined when it was built.
If your careful, and use plenty of epoxy...to the point it's oozing out of the wing joint you'll be fine without the glass. It's a judgement as to how much is enough when it comes to that...but you can have enough paper-towels, and denatured alcohol to clean up any excess if you end up with too much in there. I've always done them like that, and not had any failures yet, and confident that they won't.
I am glassing the one I'm restoring, just for the fact that it's already uncovered, and I have a piped .61 going on it, and it has been on a diet, so it should move out pretty good.
They are good flying planes.
Oh yeah....the JR servo will work, however...the linkage will be a trick to set up if you haven't done one before... a true retract servo has 180'degrees of travel(along with alot of torque), but I have successfully used standards on the retracts...so I don't think torque is an issue with these..it's a matter of getting the linkage correct. Good luck......
Oh....PS.....If you have the firewall to thrust washer dimension on these , I'd appreciate you posting it here....It has been a few years since I've done one, and I don't have any books left on them. I'm thinking it's 6.25"....or is it 6.0"?? I need to set the engine mount myself...that's pretty much where I'm at before I cover it. Thanks, and good luck. :)

RE: World Model P51 ?'s
 

Well I have a couple of these. One has a .90 mounted sideways and the other has a Saito 100 inverted. You really should strengthen the fron end both inside and out and its not much work. Instead of actually using glass cloth use a mix of epoxy and Great Planes Milled fiberglass. Its just as strong. Run it along the firewall corners on the outside and the indside and a bit along those stringers. You don't need to apply pounds of it but just simple beads for added strength.
* Also slop some on the inside area of the retract mounting blocks. Y9ou may have to remove them but its no problem. This is one of the smoothest flying and hot P-51s for it size on the market. Another thing about the plane unlike most other warbirds is the front end being so aerodynamic. Everybit of the prop is exposed unlike planes like the Corsair, Bearcat sea Fury etc. Its a mover even with a .46-.60.
One other thing is the elevator is run by one horn on one side if you know what I mean. I don't like it and changed it to one rod from the servo BUT I split it up like a "Y" and run to each elevator.

RE: World Model P51 ?'s
 

Thanks for the help, I went out and got some of the milled fiberglass and I will definitely be putting that on the firewall inside and out. I might even put some on the wing joint after I epoxy for added strength. dgrant, I brought the directions in to work with me today to reply to your engine mounting question. I'm not sure I understand the question but I'll copy into the forum what they put in the directions:

Installed engine position 118mm/4.65in. from firewall to the thrust washer, but I think this is for the presumed .40 or .46 size engine. I have always used oversized engines and mounted them closer to the firewall for a better cg.