Stupid question?

[idropurbox]

What is he difference between a disk valve motor and a drum valve motor. I have an OPS .45 and I know that they made both types, how do I know which one I have. Which one is better? Also mine has the slide type carb and I was reading the NAMBA rules for sport 40 and if I understood correctly the rules state that you must run the rotating barrel type carb. Is this true?

 

[piper_chuck]

I'm not in NAMBA, so my understanding of their sport 40 class is limited to what I've read. There are two divisions of Sport 40. The rotating carb rule only applies to division 1, which I believe is much less popular than division 2.

Most of the current .45 engines are drum rotor rather than disk. I think the drums are better/more durable. The drum/disk controls the intake by only opening it during the compression stroke. The disk rotor is as the name implies, a metal disk. The drum is a cylinder shape instead of a disk.

This is a drum engine:

The part where the carb mounts to the engine would be about even with the back of the cylinder on a disk rotor engine.

 

[idropurbox]

I'm not in NAMBA, so my understanding of their sport 40 class is limited to what I've read. There are two divisions of Sport 40. The rotating carb rule only applies to division 1, which I believe is much less popular than division 2.
Most of the current .45 engines are drum rotor rather than disk. I think the drums are better/more durable. The drum/disk controls the intake by only opening it during the compression stroke. The disk rotor is as the name implies, a metal disk. The drum is a cylinder shape instead of a disk.

This is a drum engine:

The part where the carb mounts to the engine would be about even with the back of the cylinder on a disk rotor engine.

Thanks, I believe mine must be the drum motor, but instead of the being round the part where the carb mounts to the backplate is square.

Tom

 

[Bob Howard]

If you have a .45 you will need to run in sport .40 II, The sport 40I class only allows engines up to .40, hope this helps

Bob

 

[idropurbox]

If you have a .45 you will need to run in sport .40 II, The sport 40I class only allows engines up to .40, hope this helps
Bob

OK, thanks.

 

[Watercadet]

Welcome to District 19! Chuck was correct in answering your question both on the class and your induction type.

D 19 has a healthy class of both Spt 40 I and Spt 40 II. Bob was also correct that you would be in 40 II.

Spt 40 I seems to be very popular with the older modelers who have a lot of the equipment for that class from their old r/c planes. 40 II is the fast class, with modern hulls, motors and ....TUNED PIPES!!! The 40 I guys run mufflers.

 

[idropurbox]

Welcome to District 19! Chuck was correct in answering your question both on the class and your induction type.
D 19 has a healthy class of both Spt 40 I and Spt 40 II. Bob was also correct that you would be in 40 II.

Spt 40 I seems to be very popular with the older modelers who have a lot of the equipment for that class from their old r/c planes. 40 II is the fast class, with modern hulls, motors and ....TUNED PIPES!!! The 40 I guys run mufflers.

Mufflers!!!!!! They should be banned from the pond! Sport 40 II is where I'll be then. So what do you know about the Maus hull, now known, produced, and sold by Hyperformance motorsports as the SX45?

 

[Watercadet]

I don't recall any bad tendencies of that hull. I think Maus called it a Scorpion 45. Mike Stuart used to race one that he widened one inch. Ran real well when the motor was happy.

I have a Sport 20 Maus hull that as I understand was rare, but now Hyperformance is building them! There goes the neighborhood...