Hey guru's got one for ya. I posted this on the P-51 PTS page but not sure how many are still reading that post w/ 90 pages now.
Anyway I went to the hobby shop last week to look for a prop that would give a little more speed. They sold me a graupner 3-blade 11-7 prop. When I got home to try it out the center hole is to large for the engine shaft. So how do I fix this? Also will the EVO .46 engine that come with the plane swing this size prop?
Thanks
Randy

Not only is the hole too big, the prop is too big. Get a 2 blade 11X6 or 11X5.

I agree with Jim on this one. That 3 blade is WAY too big for that engine

I was kinda wanting to stay with the 3-blade look.

That's cool. Put a 3 blade on to look at it and a 2 blade on to fly it.

If I remember correctly the standard 3 blade is a 9X4, find a 9X5 or 9X6
If the hole is too big and it is not by much then you can put tape around the prop shaft or use heat shrink tubing around the prop shaft

I just looked at the manual and if that is the PTS trainer system and it should be unless you chaged it then it is the EVOE100 model and it takes a 10X6 2 blade max, so either a 9X5 or 9X6 3-blade will be fine

NT/NX Evolution Enginesâ„¢ Specifications
Disp Bore Stroke Weight Crank K
w/o
Items (cu in) (in) (in) (oz) muffler (ISO) Cylinder Propeller
EVOE100 .455 .867 .771 16.32 1/4x28 ABC 10x6
EVOE0360 .354 .806 .695 10.30 1/4x28 ABC 9x6
EVOE0400 .392 .805 .771 14.08 1/4x28 ABC 10x6
EVOE0460 .467 .864 .797 13.76 1/4x28 ABC 11x6
EVOE0610 .608 .944 .862 20.10 5/16x24 ABC 12x6
EVOE1100 1.005 1.14 .985 23.20 5/16x24 ABC 14x6

Thanks guys for the help. Anybody wanna buy a 11-7 3-blade????? CHEAP w/ spinner/[&o]

In the air, no one will know if it's a 3-blade or 2-blade prop. Don't risk the plane for a scale prop. There are a lot of scale detail you can easily add without messing with the engine.

A .40 can NOT swing that much prop. For pure speed with this plane and engine, I'd go with a 10-8 or 11-6.

With all due respect to bubbagates, if a prop hole is too big, DON'T use tape or any other flexible or compressible medium. Plug the hole with a hardwood dowel and re-drill it. If it's a LOT too big, you can also use a brass or steel bushing, usually found at Home Depot or Lowe's.

Dr.1

DR. 1 has a way better way and much more reliable to make the hole the proper size

Hi!
As you use a 7,5cc engine (.46) the correct 3-blade prop is a 10x5 or 10x6...Not a 11x7 or 9x6.
As for fixing the too large hole...one metod is to turn a aluminium spinner nut like the one I have in the picture (Can make it for you) or find a brass (K&S) tubing that could act as a spacer. Do not fill the hole with a dowel or wind tape around the axle....[8D].

Regards!
Jan K
Sweden

Nothing like blowing your own (prop nut) horn while you're at it, jaka. I've filled many props with HARWOOD dowel, and the method works well. Drill the prop hole just undersize for the dowel and tap it in place. Soak the front and back with thin CA, sand flat, and carefully redrill with a bit that makes a snug fit on the crankshaft.

Dr.1

Since we are talking prop size, how much does the size of the spinner affect in determining adequate prop size. For an exagerated example... 10x6 with a 4" or no spinner. How much rpm loss or gain, however you want to look at it. Just a thought.

Layne

I really think this prop thing is the most complicated thing about these airplanes. So help me with this, the stock prop that comes with the P-51 PTS is a 10.5 x 4 3blade. What what kind of results will I get by changing to a 10 x 6 3bladed prop.
Thanks for all the input here.

Randy

GIVEN THE SAME RPM:

Larger diameter, less pitch gives more acceleration, less top speed.
Smaller diameter, more pitch gives more speed, less acceleration.

It's like low gear/high gear in a car.

A pylon racer with a .40 may use a 9-8 prop. It goes like stink, but takes a lap to get up to speed.

A competition fun fly plane with the same .40 may use a 10-4 to 12-4. Not fast, but instant acceleration to flying speed.

What will your plane do if you change the prop? Good question. Buy one and find out. Several posters have already cautioned you against using a 3 blade prop. Smaller diameter will not fly that plane better, or necessarily faster. Use a 10-6 or 11-6 TWO blade prop for good flying qualities.

Dr.1

Thanks DR1 guess I'll go TWO blade then.

You won't be sorry, 71.

In addition to the extra loading a third blade puts on the engine, there's a matter of efficiency. Three blade props are not as efficient as two blades, and smaller props generally as not as efficient as larger props. If a prop turns too fast, or a blade turns in the turbulence of the preceeding blade, it may it cavitate. This absolutely kills pull and speed.

You're right in a previous statement you made. Prop selection is VERY critical to the flying qualities of your plane. All props are not created equal. A 10-6 from one company may give completely different flight characteristics than a 10-6 prop from another company. In the sizes we're discussing, I MUCH prefer the APC brand over any others I've tried. They're a tough prop and seem to be very efficient. Even though it may cost a little, try different sizes and brands until you find one YOU like, then stick with it.

Dr.1

Thanks Dr1 I'll do that. By the way where do you fly at down there? You with the SKYKNIGHTS or the FIRETOWER FLIERS??? We fly just off I-26 near the Asheville airport, maybe you could come up and burn holes in the skies with us.

Thanks for the invite, 71, I might just take you up on it. I'm a member of the Spartanburg Sky Knights and the York County Flyers. I recently went a warbird event at Blue Ridge, and I like their new field a lot. I might join there, too.

I fly the Dr.1 and a sport plane of my own design, the Piranha II. On the building board are a Spook 96, a Top Flite Corsair, a Guillows Dr.1, A HOB F-86 with a Kress fan and OS .25DF, an Estes Shark, and another Dr.1. Looks like I'll be busy for a while! Whew!

Send me some directions and flying times. If you want to e-Mail a phone number, I'll call you when I can come up.

Dr.1
(Gerald)

Sounds good. I've been down to the Knights a couple of times when you had your FF. Was there with Harold Little in the Quick of Japan tent. We've got Bradley now as one of our Reps. Good kid right there.

Randy