Rflyin

My Feedback: (6)

Hello,
I had decided to fly in a local clubs 1st pylon race. I bought a viper and put mt TT46 pro on it and while practicing the night before the race, the rear bearing decided to destroy the motor. I was able to borrow a tt40 with a ultrathrust on it but I was a lot slower then the 46s the other guys had. So I flew the race, had fun but now I need a motor. It has to be 46 or less, under 150$ but can use the ultrathrust or jett mufflers. I know little about the motors being raced today. The searchs I've done seem to lean to the OS 46ax but most of the posts were several years old. Prop to use would be helpful to.

Thanks,
Rick

skull1971

What was everyone else running? I'd say a Rossi or a Webra, but i think they might be over the $150.00 limit. If you decide to go with the OS engine, try to find a FX46, Bob27 on here (RCU) said the the FX will rev higher. As for a prop, I'd guess, a 10x7 or 10x8, but others on here know better than I do. Have fun and keep us posted on your racing.

daven

My Feedback: (1)

The FX .46 will definately rev faster, but the AX is a stronger motor. I would go with the AX and Ultrathrust muffer and shoot for around 15,000 (whatever prop gets you there)

2fast4u

My Feedback: (5)

Years ago I ran the OS46FX with a Mac tuned pipe, 10% and an APC 10x6. It would turn 15-15.2K all day long. I think daven is correct that the AX is a stronger engine. I run mine on 15% & Ultra Thrust muffler and it turns a 12x4 really strong! I have never tried a shorter prop for higher rpm, but I bet it will do fine with the ultra thrust muffler.

vicman

My Feedback: (10)

Those pesky bearing cages[:'(].
Can you replace the bearing and get away with that?

Rflyin

My Feedback: (6)

Thanks for the replys,
The pistons pretty chewed up so the price of a set of bearings and a piston and sleeve I think is better then half the price of a new one.
Daven, you say the fx will rev faster but the ax is stronger. Can you elaborate?

Thanks,
Rick

daven

My Feedback: (1)

I started racing quickies in Minnesota in 1999. The ONLY motor that was allowed was the O.S. .46FX.
Most of the top competitors in our area would run the 8.8"x8.75 APC pylon prop at a little over 16,000 rpm. Seemed to be the best combination for that motor and plane.

When the AX came out, we had to allow it (as the FX motors were no longer available). Shortly thereafter, If you weren't running an AX, you weren't competitive. They are, without a doubt, quite a bit stronger. Although, we found out, that the AX wasn't as comfortable turning max rpms like the FX. It was much happier turning a 10x7 sport APC, or APC 9 1/2" x 8.5 in the 14 - 14.5 k range.

The AX will rev right up there with the FX, however, it seems to develop its peak power in the 14-15,000 rpm range. Going any higher gives you diminishing returns.

Rflyin

My Feedback: (6)

Thanks Daven,
Looks like the AX is what I'll get. Do you have a specific breakin procedure that you use?

Rick

daven

My Feedback: (1)

Yep.

I run either 15% powermaster or Omega fuel with 4oz of additional castor (per gallon). Put either a 10x6 or 9x7 prop on the motor and run 1/2 a gallon through the motor on a test stand. Starting about 2,000 rich for the first few tanks, and ending up about 1,000 rpm off peak for the last couple of tanks. About every 15 seconds pinch the fuel line bringing the rpms up. After that, put it on a plane with the same prop, and fly big loops or climbs and dives for another half gallon running 500-600 rpms off peak. After that, you can go to the 10x7, which runs great on the AX, about 300-400 rpm off peak.

You can speed up this process, but I've had best results with the full gallon break in.

Rflyin

My Feedback: (6)

Thanks again,
Two more questions, Have you flown this motor against the Supertigre and Evolution motors both of wich were there that day and seemed very fast and Which ultrathrust the sport standard or the racing version?

Rick

daven

My Feedback: (1)

I don't run the ultrathrust mufflers on my AX motors, but I would suggest the Sport muffler. The racing muffler will not be effective unless you get the motor over 19,000 rpms (which is not suited for the AX).