splais

My Feedback: (25)

Fellas, If I have an OS46 I want to max out for speed on a Balsa Nova what prop would you recommend as a starting point. I also would like the same info if I decide to put a OS50 in her. thanks

splatt

That red thing in the avator uses a 46fx, it weighs 3.5 lbs and I'll use anything from APC 8.8x8.75 to 8.8x9.5

the 9.5 takes a bit to launch, bit tough to tune, can get a bit hot. But do a high speed pass and grin..

then bolt on a Nelson and the OS will go in the trash

Mike Connor

My Feedback: (5)

I like a 9x7 APC for speed on a 46 FX but the Balsa Nova is not a speed plane. I would go with a 10x6 for over all best performance.

bob27s

My Feedback: (19)

I agree with Mike. Use a 10x6.

The BN is a 'thick' airplane - can be quick, but its somewhat draggy, and is fairly large. The 10x6 will give you a decent balance of speed and over-all flight performance.

splais

My Feedback: (25)

yes, I realize its not a speed plane. But I have it and it is pretty quick with a 12x5 so I thought I would just turn it into a fun fast-as-I-can-get her plane. I have to order some props (no shops around). I'm surprised at the 10x6, I was thinking more like a 10x8. I'll see what I can dig up

bob27s

My Feedback: (19)

I have no doubt the plane will move out a bit And you are on the right track.

The OS .46 develops its best power with the stock muffler as it approaches 15,000 rpm. Most of the OS 46FX engines I ran turned a 10x6 around 14K - 14.5K on the ground, and unload in the air up into that 15K power band quite nicely. You should try and prop in that power band. An APC 10x7 works very well too (in some cases better than a 10x6 - unloads better at speed).

I am not sure on the 10x8 - will likely drag the engine down around 12.5K - and the plane will not move fast enough to allow it to unload enough in the air. Who knows, give it a try... might hit a balance there.

Simple rule for speed props. Use small diameter (less frontal disk area) and higher pitch for speed. Use larger diameter, flatter pitch for slow/scale/aerobatics (anywhere you want airflow and static thrust). Know what RPM your engine wants to run best at, and try to keep it there.

daven

My Feedback: (1)

Bob is correct, the FX develops its best power between 15-15.5k. A 10x8 just won't get the rpms up enough to get you there. A 10x7 will be close, but I think the apc 10x6 will be the best prop for speed on your plane. The pylon props seem to struggle on bigger planes. You may want to try a couple pylon props though, 9.5 x 7.5 N or 9.5 x 7 N these may work also.

Rcpilot

My Feedback: (78)

You can hop up the 46FX with a new liner and piston assembly for the 46FX-Heli.

They are the same engine internally--just the heli is a ringed setup. You'd need to buy a liner--piston and ring.

Cost ya about $60--but GAWD LORD!! It WILL run WAY better than a 46FX.

I did this to a 46FX that wasn't broke-in right. Friend gave it to me after he splattered a couple gallons of fuel through it 4-strokin' rich the whole time. I told him to get it hot-ABC/ABN, but he wouldn't listen. He ruined it and won't ever buy another OS. POS he said. I gladly took it off his hands for free.

I put the liner/ piston/ and ring assembly from the heli engine and broke it in with a gallon of 10% Omega. It's all the same porting and duration, just a ringed setup. I don't know why it ran so darn good--but MAN it was RIPPIN'!

At 6000' altitude and an APC 9-6 pylon prop--10% fuel--I had it tacking 15,800RPM with a tuned pipe. Not too shabby at this altitude. Considering a stock FX on a pipe won't get over 12K with same prop and fuel.

That oughtta pick up your speed a bit--but is it worth $60 to ya?