fun fighter P-51
 

I just picked up a used model tech fun fighter P-51. the plane calls for a .25-.36 two stroke. I've read claims of 140 MPH with a .36. I just finished installing a .46 :D the recommended CG is 75-80mm from the LE at the fuse, I have it at 3" from the LE and still have to add the RX battery, so balancing will not be an issue. what prop would you guys recommend for max speed out of this set up. the engine is only an OS .46 LA so crazy RPMs aren't going to happen. here's a few pics

RE: fun fighter P-51
 

That muffler is going to make a fine speed brake. You need something that has less frontal area. If you still have the stock muffler it would be a far better choice.

I would try a 9X7.

Wiggy

RE: fun fighter P-51
 

Have fun with it, love those Mustangs!. It would be interesting to see an engine thrasher do a thread like this. First get a base line rpm and plane speed, then do a stage by stage hop up of the engine and even the plane to see what is possible.
How much does the plane weigh?

RE: fun fighter P-51
 

put a tuned pipe or jett muffler on it then watch the thing get with it. the la 40-46 actually respond well to this mod:D

RE: fun fighter P-51
 

the "claimed" weight RTF is 3.3lbs, I haven't tried to weigh it but it feels pretty light

RE: fun fighter P-51
 

Sounds good and light, that really helps everything go as planned.

RE: fun fighter P-51
 

is your head on backward on the engine?

RE: fun fighter P-51
 

I don't think so, I got this engine in a different plane from a guy at the field. it runs good. I'll have to go look at it. don't they have a guide pin in them?

EDIT: no it's on right, it looks like it can only go one way.

RE: fun fighter P-51
 

it can mount forward or backward, its a schnuerle design, not baffle piston type.......the sleeve has the guide pin slot

RE: fun fighter P-51
 

It might do quicker loops though, with that drag from regular mufflers when you pitch the nose...? :)

Ditto on the 9-7, a good first choice (and maybe last choice) for many .40-.46 "brisk" aircraft that don't qualify as speed designs.

MJD

RE: fun fighter P-51
 

3.5 pounds with Jett 35 and landing gear, Hitec 225's, JR 600 receiver and 600 mah battery. Yessssssssssssssssssssssssss. My sweet well loved 35 is up and amoung them again. Sadly, no one will come up to play, yet. Airframe turns just fine, best guess around 120mph with that draggy landing gear. Have some small retracts, but did not use because of the gear weight limits of 3 pounds. If need be, the gear can come off and be hand launched. Not at our very rough asphalt field scheduled for resurfacing soon. Only thing to watch for is takeoff when ROG. Is squirly if you taxie for takeoff in the usual manner. Suggest buddy hold, crank her WFO and let it go with 4 or so clicks uptrim. Will be in the air before the engine torque pulls it around too far. ENJOY

RE: fun fighter P-51
 

went back and looked at pic. it looks right. just under my quick glance it looked turned around. It wouldnt hurt anything though.

RE: fun fighter P-51
 

I finally finished the P-51 today. I tached it today and static it's pulling a MAS 9x8 prop at 13600. I tried an APC 9x7 it pulled it at 13300. it's funny how an APC prop is so much harder to turn. I'm going to maiden it on sunday and see how it goes. it should be the fastest plane I have.

RE: fun fighter P-51
 

apc props actually measure at true helical pitch and master  airscrews often measure at a lesser pitch than what is stated, 10x6 master airscrews often measure at 10x5, hence your apc turning less RPM because it actually has accurate pitch

RE: fun fighter P-51
 

Hi Sportrider,

I can't tell for sure but is that a crease in the wing or is it a glitch in the photo? If it is a crease I would be very careful about flying at any speed until you carefully check for damage to the wing...

Good luck

Carlos G.

RE: fun fighter P-51
 

it's just a wrinkle in the covering.

well Iflew it today, and although it's quick, it's not even close to the speed I'm looking for. my guess is probably in the mid eighties. it's a good flyer but... not fast enough. maybe I'll try my magnum XLS .46 in it and see if that will turn more pitch or should I just put a 10" prop on it?

RE: fun fighter P-51
 

The engine needs to be upside down and set with the bottom of the engine as high as it can go within the confines of the cowl. I'll bet that gains you more speed than swapping engines.
If you want to go 120-130 mph with a $50 kit, look into the House of Balsa P-51.