Someone I know put a 13b in a sitdown a couple of years ago as a prototype that worked pretty well then he started working on kits to do it, but that project fell by the wayside sort of.



Anyway, I do freestyle on a standup and we're always looking for more power of course. I'm currently running a ~115hp 701cc 2-stroke. The biggest engines are running ~850cc and 180hp.



I came across rotaryengines.ca and their ultralight aircraft twin rotor engine that is rated for 75hp with efi. So I started thinking, what about taking that engine, drop the reduction drive, efi, water pump, etc. and adapt it to a ski. They sell their single rotor version in a kart version that is just that and rated at 41/42hp@6900rpm. Most jet drives work best up to around 7500rpm so this engine seems to fit, except for the power.



Also, their engine's torque peak is at 4000rpm which would be a huge improvement over our 2-strokes which typically peak 5500 or higher.



And another also, their engine is lighter than what I'm running so that's an improvement already.



So, what I'm wondering, can the same type of mods you guys are doing be applied to a much smaller engine like this (400cc/rotor)? What could I expect to see for a strong setup. I've heard n/a you can max a 13b at about 150hp/rotor, right? This would be somewhere in the 1/2-2/3 range if you go by cc's, so could I see maybe 75-100/rotor?



BTW, an engine builder I've dealt with before is interested in this project and wants to work on it this winter, but we need to know we can get the numbers out of it we need.



Any help is appreciated.







(already found the 1 thread on here about transplanting a 13b into a pwc where he was mainly looking for a hull)

 

wow, will be a sweet swap!

 

So does anyone have some insight into mods I could look into that would be applicable to any rotary engine or what kind of hp I could expect from a twin rotor 800cc engine?

 

What do you do gearbox wise?



Mark

 

[quote name='inanimate_object' date='Aug 18 2005, 04:43 AM']What do you do gearbox wise?



Mark


[/quote]



It's direct drive, no clutch, no nothing. We'll have to do a gear or pulley offset to get things aligned, but that's not that big of a deal.



Our jet pumps run best up to about almost 8000rpm, so it fits well with most engines' powerbands.

 

[quote name='SuperJETT' date='Aug 17 2005, 02:26 PM']So does anyone have some insight into mods I could look into that would be applicable to any rotary engine or what kind of hp I could expect from a twin rotor 800cc engine?


[/quote]



Well I would say have a thorough read of the longer topics in the engine building and porting forum here, paying close attention to posts by Judge Ito, Lynn Hanover, and BDC. Since 12As are about 1.1L and can be got to nearly or perhaps over 300hp, you should be able to see over 200hp from your engine, in theory.

 

There is another engine out there that would probably be much more suited to your application.

Check this out www.uavenginesltd.co.uk thay make small rotary's for the UAV market.

They have a twin rotor water cooled engine of 2x294cc. They have seen over 140hp on dyno's and weigh next to nothing.

Hope this helps

 

[quote name='skiier' date='Sep 15 2005, 04:46 AM']There is another engine out there that would probably be much more suited to your application.

Check this out www.uavenginesltd.co.uk thay make small rotary's for the UAV market.

They have a twin rotor water cooled engine of 2x294cc. They have seen over 140hp on dyno's and weigh next to nothing.

Hope this helps


[/quote]



Thanks for the info, we'll check with them too.



As we've gotten into the research, it's looking more and more expensive due to needing a 1:1 gearbox to get things lined up properly which adds weight/money/etc.

 

Those look a whole lot more promising than anything Freedom Motors (Moller) has come out with in a long time.

 

I contacted UAV Engines, and got a polite "we only deal with the military" answer. At least they responded. Freedom Motors never gave us the time of day.



Looks like Rotary Engine Technologies is our only option based on being the same or lighter weight than what we currently use.