Mr3Putt

My Feedback: (2)

How does the O.S. 46AX hold up under racing conditions? I had a 46FX and the sleave and piston peeled after all out racing so I'm reluctant to burn up another engine. Also, what fuel would you recommend - nitro/caster %. Using same setup, which would be faster: O.S. 46AX or Thundertiger 46 Pro?
Thanks

daven

My Feedback: (1)

We've been using the O.S. .46 FX for racing for quite a few years (More than 6 that I'm aware of). They have been great engines that hold up well, they did have some peelers a few years back, but I haven't seen any recently. A good prop for the .46 fx is the APC 8.8x8 3/4". It should turn about 15,500 rpm and be good for about 120 mph.

This year, we've agreed to allow the .46AX and its a hair stronger, but developes it best speeds when you prop it to run about 13,500 rpm. Believe it or not, but an APC 10x7 is about perfect and does 125-130 mph when set up right with a good plane. Unfortunately, our racing rules require a D-1 Hub, so the Sport prop is not allowed.

We've liked these engines because they are pretty similar, with little difference in speed between them.

daven

My Feedback: (1)

I missed your fuel question. We run Omega 15%, which I believe is about 18% total oil, with 30% of that Castor and 70% synthetic.

Another good choice is Powermaster 15%

Dave

diggs_74

I'm pretty new to the racing thing but I have learned that the AX doesn't need as much room for "unloaded" conditions as the FX... I just recently started using the AX and I found that I'm within about 400 RPM of full lean on the ground.... The FX is around 1000 RPM from full lean on the ground with the same prop (8.8X8.75 APC).... Must be a porting diffence or something.

Conrod

So is the 8.8x8 8.75 no good on the AX, and if you can not use the 10x7 what is the best?
Geoff

Randy Etken

My Feedback: (10)

The 8.8X8.75 is just fine for the OS 46AX. If you check the NCPL Q500 races for this year will find my partner Chuck Elridge and I have won every race using this prop. Some are using
9.5X8.0 and 9.5X8.5 which also work will. It still comes down to the thumbs.
Good Luck

Mr3Putt

My Feedback: (2)

Thanks for the excellent responses. I'll give the 8.8x8.75 APC a try. After 20 years in the hobby this really gets the old ticker pumping. I love it as do all the onlookers.

growingupisoptional

Along the same lines all things being equal, what would pull more rpm. An OS AX 46 or a ROSSI 45?
Rossi would be fitted with an ENYA exhaust to fit in with our front intake side exhaust rules (no tuned pipes).

Cheers J