Radial Engines - Pros & Cons

What about this kind of engine? Can it be used for a paramotor? What are the pro’s and cons?

 Type        SPARK IGNITION     
 ---     ---     
 Cylinder Type        7(ABC TYPE)     
 Bore        35.7MM     
 Stroke        37MM     
 RPM Range     1000-5500     
 Weight of Engine     6700g incl.(ignition coil & silencer)     
 Engine Diameter     320MM     
 Length     215MM     
 Prop Range     32X12,32X14,32X18     
 Muffler Type     COLLECTOR RING     
 Plug Type     CM-6     
 Carburetor     WT 621     
 Power     15.6 HP     
 Tank Capacity     260CC     

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I was looking at this engine just today wishing I could put one on a paramotor…

You would either need a gear reduction or a 600-700cc radial engine to have a decent size prop and even though they are 4 strokes, they still burn oil. Other disadvantages include more maintenance, much higher cost, harder to find parts, and an amazing sound that you just cant resist, so you will be flying a lot. lol.

Radio control radial engines run at a much lower rpm than 2-stroke paramotor engines, so you tend to need a much bigger radial engine for the same power. because of this, I recommend looking into Moki radial engines. You can find them up to 500cc and about 25hp which would be better for most people than the 15hp 260cc engine you have specs pulled up for.

Someday I will make a radial engine powered paramotor with Moki 400cc or 500cc engine and a gear reduction as it would sound amazing and look awesome, but it would be one of those show pieces that you wouldn´t fly often and it would be more for taking to airshows and fly-ins just to blow peoples minds.

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I found one of the engines that Bratwurst was talking about on ebay for $2750. This forum won´t let me post a link to ebay, so you would need to look it up.

¨Konig SC430 3 cylinder radial two stroke engine re-manufactured excellent cond!¨

Here’s a link I found:

Apparently, Germany’s Konig was sold to Italy’s Zanzoterra, which was then sold to Canada’s Compact Radial Engines

There seems to have been a larger engine, SD 570:

It weighed 19kg (42 lbs), and produced 28 hp, but was downrated to 24 hp.

Is that kind of downrating done to preserve engine life, or reduce fuel consumption? I can never find any fuel consumption figures for these radial engines.

Also, are fewer cylinders better, in relation to a given horsepower? And if so, then why?
Any such thing as a 2-cyilnder radial engine?

Here’s a Rotary Radial engine:

Apparently, these were developed (back in WW1 :face_with_monocle:) because their rotation helped to aspirate the engine, as well as to further cool it. To me, it would also seem that this engine rotation could perhaps also usefully counter torque.

Obviously this particular model is large, as it’s meant for a full-sized aircraft.
Has any smaller version of something like this ever been used with a paramotor?

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I am under the impression several posts in this forum are getting way off topic lately.

Captain Obvious says: This forum here is related to ELECTRIC PPG.

People that come here are usually not looking some potentially usable designs or multi cylinder piston engines. We can all find hundreds of youtube videos on those topics easily.

If would be great if we could keep a bit of focus to keep the forum valuable and move unrelated stuff to other e.g. regular (thermal engine) PPG forums.

Alright, what about the Electro-Motive Diesel engine (EMD), or ‘pancake diesel’

https://en.wikipedia.org/wiki/Electro-Motive_Diesel#EMD_‘pancake’_diesels

These lightweight radial engines were used to generate electric power onboard submarines, so that they could be propelled electrically. Could these likewise be useful for generating electric power for an ePPG?

What are the pro’s and cons of that approach?

They just call it a 2 cylinder boxer engine or a flat 2. The dle 170 and dle 200 is a common example of this type used by some paramotorists.