I am looking for advise on my max 40 engine and hoping some one can help.I have this motor mounted on a profile ringmaster and it is running pressurized with a muffler.When i fly this plane it is running real fast but does not sound like it breaks into a 2 stroke cycle when doing maneuvers.the current set up is a 10x6 prop,large venturi,and 2 gaskets under the head (from the factory).Should I try a different size prop or take out 1 of the head gaskets to get it to cycle Thur a 4-2 engine run. Any help is greatly appreciated thanks.

I suggest you try the Philly FP setup before giving up the FP. The RingMaster will fly just dandy with the CG right up to the LE.

Using a lighter engine will allow you to make better corners and if that is important to you then consider replacing the engine for a lighter one. If that is not the case  I think youŽll have a blast with this combo you have there.

RSM has a very light tonge muffler for the 40 FP that would help reduce the weight.

OS 40FP e 35FP Philly Setup:

Venturi .283”
free flow exhaust
extra head gasket or two
powermaster 5%,22% (50/50)
10.5x4.5 APC prop.
Muffler pressure in the overflow, plug uniflow if you have it.
Enya #3 plug

Set it in a 2cycle. Should sound fat and happy and somewhat loud. If engine runs away and fuel consumption is low. Open up the exhaust more and perhaps venturi Will also need opening to compensate for the thickness of the ST needlevalve.

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It will be very loud though.

Martin

Scott, A tongue muffler can be set up to run pressure you just need the fitting put on it. Powermaster is a brand name fuel like Sig or Cool Power, I believe Horizon Hobbies sells it now. Go with the smaller venturi to slow it down.

Scott,

the Philly setup will not run 4-2-4, it runs a wet 2-2-2  generating a lot of torque which will keep your plane going up and down at the same speed, better then 4-2-4 in my opinion.

If you want to run this engine in 4-2-4 the approach is quite different. A local guy here has one and it works very well in 4-2-4. I never saw him having run way problems even in days with good temperature change.  He decompress the engine quite a bit, uses a small venturi, stock muffler restricted with a deflector and a 11x6 prop. The nice thing about his setup is the sound, sounds and run just  like an ST 60. However it is gutless, any breeze and he doesn't fly his RD-1. If you want I will have him write to you and tell what he does to his 40FPs

Martin

        Dennis from the Philly Fliers runs the Fp.40 exclusively. In fact I can't recall him running anything different other than the Tower.40 which is virtually the same. I would follow the instructions as Martin stated above. We've found that the engine runs happiest when its running fast. This is where the APC 10.5x4.5 comes into play. That prop allows the engine to run fast but without the plane going fast as your 10x6 is doing. The tongue muffler allows it to breathe easier and the LARGE venturi keeps up the fuel supply which in turn cools things down. When the engines are cowled in a full bodied plane thats when you really need adequate cooling (air passages) to keep the engine from heating up and running away. I would add an additional head gasket or 2 which will also tone things down a bit. Dennis was flying his Galaxy with a FP.40 on it until I noticed he just switched to the Tower.40. I think this was mainly just to see how it ran. He does the same mods to the Tower engines as the FP's. The plane was running very reliably last weekend providing a good stunt run. The only thing I would question is the weight of the FP on the Ringmaster. The Ringmaster if built from a Sterling kit typically builds nose heavy to begin with.  I see mainly Fox.35's on most of the Ringmaster's I see flying. You now have a engine thats almost 3 oz's heavier than the Fox. This weight could even be more if your using the stock muffler. I'm sure Dennis will chime in when he comes across this post. Ken

Scott,

I suggest you get the prop and all the material you may need from dedicated C/L vendors  like Aeroproducts, Brodak, RSM....

A local shop with no expertese in C/L will most likely give you wrong advice. Before buying or doing anything look for help here.

The RSM tongue muffler is the lightest one, half the weight of the others. You need fit a pressure niple and drill another row of holes that is all.

The total number of head gaskets is one or two, in some rare cases 3. RSM also sell the gaskets in case you need new ones.

Martin