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TECHNICAL MOTOBRICK WRENCHING In Remembrance of Inge K. => Project Custom Motobricks => Topic started by: FranK75 on November 14, 2015, 09:57:12 PM

Title: K engine driving an ultralight
Post by: FranK75 on November 14, 2015, 09:57:12 PM

The K engines are powerful, high output for their weight, reliable. I am considering using a K75 engine to power an ultralight airplane. May have to shave off weight where ever possible.

Title: Re: K engine driving an ultralight
Post by: Chaos on November 14, 2015, 10:07:09 PM

good ones are pretty cheap on the market too.  Not sure how you'd shave weight aside from the transmission & clutch.  Maybe lighten the flywheel.

Title: Re: K engine driving an ultralight
Post by: FranK75 on November 14, 2015, 10:11:57 PM

I would grind off as much aluminum as possible from all over the engine

Title: Re: K engine driving an ultralight
Post by: Chaos on November 14, 2015, 11:36:38 PM

Seen R100 and 1100 engines on ultralites and small planes.  Makes sense, no radiator to worry about

Title: Re: K engine driving an ultralight
Post by: Mongrel on December 07, 2015, 01:08:03 AM

Yeah, maybe something air-cooled would have a better power-to-weight ratio? Not sure, but worth looking into!

Title: Re: K engine driving an ultralight
Post by: FranK75 on December 07, 2015, 10:34:40 AM

Great points on the air cooled. Thanks - makes more sense.

Frank

Title: Re: K engine driving an ultralight
Post by: wmax351 on December 09, 2015, 11:49:55 AM

Air-oil cooled R11's or R12's are probably a better bet. The oil cooler can be thermostatically controlled, and potentially controlled with flaps. Also, carbureted and can be set up with dual plugs and (potentially) magnetos. Don't want engine failure from electrical failure. That way you can duplicate critical parts.

Counter Balancer adds some weight too.

BMW bike engines are good for this, they have a high duty rating, and separate engine/transmission.

You will need to consider the thrust loading on the output shaft. If you are doing a reduction drive (which I would assume you are) that will take care of it.

Title: Re: K engine driving an ultralight
Post by: F14CRAZY on December 09, 2015, 12:17:40 PM

Someone's done it before

http://www.homebuiltairplanes.com/forums/general-auto-conversion-discussion/4438-bmw-motorcycle-engine-plane-3.html (http://www.homebuiltairplanes.com/forums/general-auto-conversion-discussion/4438-bmw-motorcycle-engine-plane-3.html)

Title: Re: K engine driving an ultralight
Post by: Laitch on December 09, 2015, 01:12:39 PM

It'd be more adventuresome to use a Ural engine; however, you'd probably be making shorter flights. :hehehe

Title: Re: K engine driving an ultralight
Post by: FranK75 on December 09, 2015, 10:50:43 PM

No problem. I would bring lots of tools and spare parts.

Title: Re: K engine driving an ultralight
Post by: Chaos on December 09, 2015, 11:26:30 PM

Quote from: Laitch on December 09, 2015, 01:12:39 PM

It'd be more adventuresome to use a Ural engine; however, you'd probably be making shorter flights. :hehehe

As a rabid Uraligist I resent that remark though I cannot argue with it  :giggles

Title: Re: K engine driving an ultralight
Post by: F14CRAZY on December 10, 2015, 05:53:20 AM

How about a Chang Jiang engine?