rotary engines ?

[VELOCIS]

Has anyone ever heard og using rotary/wankel engines in marine applications?<br /><br />I would have thought there may be some benefit to the extended rev range considering the lack of multiple gears ?<br /><br />I have an older complete 70HP engine setup minus a blown powerhead, some cash for a small rotary engine and a good imagination !

 

[ivar]

Re: rotary engines ?

Extended rev range yes , but probably a lack of torque compared to a conventional setup.

 

[rodbolt]

Re: rotary engines ?

yes its been tried and actually worked quite well. rotor sealing problems plaged the early versions and oil problems as well as excessive fuel comsumption. a rotary is almost a 2 cycle. they generate tremendous exhaust heat. and by the time the tech advances were made in seal technology the projects were just not economically viable<br />I have seen the 2 rotor mazda used on airboats and inboard small boats but it was a frankenstien .<br /> good luck and give it a try.

 

[ED21]

Re: rotary engines ?

Rotaries always suffered with lack of fuel economy.<br />I drove a Mazda RX-7 some back in the mid '80's & it would push you back in the seat like any V8.<br />The car was geared low, so maybe the high reving helped its performance. <br />Don't know anything about its torque without the gearbox attached.<br />It could spin tires easily into 3rd gear if you wanted.

 

[JB]

Re: rotary engines ?

I drove an experimental prototype 35HP rotary Evinrude back in the mid-late 60s at Waukeegan.<br /><br />Lousy hole shot, but fast for a 35hp. VERY noisy.<br /><br />It was developed from OMC Snomobile rotarys.<br /><br />Never got beyond prototype. Don't know the reason.

 

[VELOCIS]

Re: rotary engines ?

wow JB thats about as close as I'm gonna get, someone who has actually seen a prototype.<br />So I know it may be asking a little much but do you happen to know how many cubic centimetres that rotary was to get 35HP and was it a single rotary ?<br />Anything else you could tell me about it.<br /><br />Thanks to the rest of you for sharing your experiences of RX7's etc.<br /><br />RX7's are still always a popular power mobile over here in Australia..<br /><br />Cheers

 

[Dhadley]

Re: rotary engines ?

"Back in the day" OMC put a rotary on a raceboat and outran the twin Merc powered boats. Since Merc runs the APBA the rotarys were invited to not return.

 

[Forktail]

Re: rotary engines ?

http://www.atkinsrotarymarine.com/

 

[jim dozier]

Re: rotary engines ?

There are some jet boats that have Rotax powered jet drives in them. I may be wrong but I think that a couple of them were supercharged. I'm waiting for a E-tec direct injected 3 rotor outboard myself.

 

[Chinewalker]

Re: rotary engines ?

There was a small Wankel powered outboard called the American Marc 10 made back in the 1960s or 70s. Saw one running at a meet a couple years ago. VERY loud, but seemed to run alright. Funky looking powerhead, too...<br />- Scott

 

[phatmanmike]

Re: rotary engines ?

there is a wankel 10hp outboard for sale in local"bargain trader" paper here for 1675 obo...., i dont know anything about it though, its a 1971 and has never been on a boat, only "test tank" hours...supposedly

 

[DJ]

Re: rotary engines ?

Look here.<br /><br /><br /> http://www.monito.com/wankel/marine.html

 

[WillyBWright]

Re: rotary engines ?

Actually that Marc 10 is an Italian MAC-10. Italian leg with a Sachs motor. I have one. Never had it running. Not enough parts. I might be interested in that motor phatmanmike, but is that $1,675? That'd be way out of my budget.<br /><br />Look here... http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=31;t=000696#000000

 

[Chinewalker]

Re: rotary engines ?

That's what I get for trusting my memory with something I read a long time ago. The Marc 10 was indeed of Italian origin....<br />- Scott

 

[RotaryRacer]

Re: rotary engines ?

Originally posted by jimd:<br /> There are some jet boats that have Rotax powered jet drives in them. I may be wrong but I think that a couple of them were supercharged. I'm waiting for a E-tec direct injected 3 rotor outboard myself.

the Bombardier Rotax engines are not rotary engines. They have pistons.

 

[jim dozier]

Re: rotary engines ?

Sorry, I just assumed that a Rotax was a rotary. I see from some other links that they make piston engines as well, my bad.

 

[RotaryRacer]

Re: rotary engines ?

VELOCIS,<br /><br />I think you have a great idea. Obviously the Mazda engines are the most widely available. You could probably create a single rotor engine by taking parts from a Mazda engine. The only part that you would need to fabricate or have made is an ecnetric shaft.<br /><br />I suspect you could get 50-70 hp out of it pretty reliably. However as others have mentioned there isn't a lot of torque coming out of any rotary engine.<br /><br />The will be some work to get a carb on the thing. You may be able to use fuel injection.<br /><br />Also the engine oil is crucial to keeping the temp down. You would need to find a way to have an oil resevoir and a way to pump it through the engine. You would have to pre-mix the gas with some oil also b/c a rotary requires oil in the combustion chambers also to keep the apex seals working good.<br /><br />Water cooling will be required with a Mazda derived engine. So some sort of water pump will be required.<br /><br />This sounds like a good project. Post pictures if you do it.

 

[RotaryRacer]

Re: rotary engines ?

Originally posted by jimd:<br /> Sorry, I just assumed that a Rotax was a rotary. I see from some other links that they make piston engines as well, my bad.

No problem. Just thought I would clarify it for you. I once thought the same thing actually. But then I saw a Sea-Doo that said "Rotax" and "Twin Cam" on it. There are no camshafts in a rotary engine so I then realized it must be a pistion engine and sure enough it is.

 

[RotaryRacer]

Re: rotary engines ?

I just took a quick look out on the net and found this.<br /><br /> http://www.boating-industry.com/output.cfm?id=509527

 

[jim dozier]

Re: rotary engines ?

Interesting link Rotaryracer. My thought was that one of the problems of rotaries when compared to 4-strokes was fuel mileage and air pollution. There are a lot of old Mazda RX7s happily running around at 9000 rpm so I don't think reliability is a huge problem. If you combined an advanced direct injection fuel system similar to the new OMC E-tec with a rotary you would significantly improve the fuel mileage and exhuast pollution of a rotary. Then you would have an engine of simple design, high power to weight ratio, and high reliability.