mkuzmukerau

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I have an OS 40FX laying around from an old plane. Can I somehow rig this with water cooling coils and use it in a 3.5cc Mono or similar hull? Anyone have any info on how to adapt it to fit flex drive or rig with a starter belt? Any help would be greatly appreciated.

Mike
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Square Nozzle

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Mike, back in the 70's when I started boat racing, airplane engines were all we had to adapt to marine use. At that time, Dumas Boats had a product they called a "Cool Clamp" that wrapped around the head of the engine. The water was picked up off of the rudder or from behind the prop and plumbed with silicone tubing to the cool clamp. The heated water then dumps over board. If you are so inclined, it's not difficult to make your own from 1/4" soft copper tubing that is semi flattened and wrapped around the head with the ends fashioned into "really flattened" flanges for Pinching the jacket tight to the head. Inlet and outlet tubes are soldered into the tube at the base of the flanges. ------ Check out Dumas, I think they still make them. They also have flywheels and cable colletts. Aeromarine has a very good cable collett and probably has flywheels also. Be sure you know the crankshaft thread size for the collett. Let me warn you up front, the OS 40 will not make a race boat out of a 3.5 mono hull. It will run for fun but the power just isn't there.

mkuzmukerau

My Feedback: (2)

Ok the cooling is no problem. But I definatly figured the 40FX would move my 3.5 (28" mono). If it really isnt going to be that fast, maybe im just better off saving the money from not buying the gear to convert it, and just buy a good 3.5 marine engine... Any thoughts?

Mike

Square Nozzle

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Mike, the marine engine is designed to give you lots of power with RPM, thus speed. The airplane engine will not put out the RPM's necessary to make the prop work efficiently. No doubt it will turn the prop but 17,000 vs 30,000 RPM makes a lot of difference. If you are interested in speed and racing and willing to dig deep into your pockets, I'd suggest you look for a good 3.5 marine engine. K&B make a decent rear rotor engine. It's lots cheaper than the thorobreds that are available, but can do a decent job with moderate nitro fuel (60% at least). Up from there is the CMB, Nova Rossi, Picco, OPS and MAC (there are others but I can't think of them all now). Of course the price is up there too. I have a MAC .21 that is a real screamer. A very impressive engine. At 30,000 RPM it drinks 60% fuel like crazy. Again, it's a pricey engine. Look around at the boating web sites and check out what's available. And I don't mean Kyosho and the other ready to run plastic "toys". Competition Marine and Aeromarine RC come to mind. Also look into a local club. There must be several good clubs in your area of Florida. Typically you will find somone that is selling his equipment to move to a different class. The NAMBA and IMPBA web sites can lead you to local clubs as well. Also the LHO is a good source.