Seller doesn't know what it is - thinks it might be a 10cc (11.5 cm in height) Serial #258. Czech maybe ?
http://www.ebay.de/itm/alter-Diesel-...item3cc4b3eaec

http://www.ebay.de/sch/rc-modellhobb...id=p4340.l2562

That's a lovely, clean design.

Same seller -
http://www.ebay.de/itm/alter-Diesel-...item3a72dfe4c2

Perhaps a Spanish ZOM ?
http://www.ebay.com/itm/Zom-2-49cc-d...item2ebd157b73

Build your own.....
http://www.ebay.de/itm/Bauplan-funkt...item53ec0331f2

Was this prototype ever sold commercially?

Image taken from "Model Aero Engine Encyclopedia" 1958, compiled by R. G. Moulton

That inline 4 would have been incredibly fun to run and most fascinating too.

In the rocking horse manure category....
http://www.ebay.co.uk/itm/AEROL-HURR...item1e6cfffe5b

"This engine is an early British diesel engine of 2cc displacement produced by Aerol Engineering in 1948 prior to its replacement by the famous Elfin 1.8cc."

On your marks - get set.........!
http://www.ebay.com/itm/Vintage-Barb...item27c5c1a68b

Gotta love the compression adjustment !
http://www.ebay.com/itm/MODEL-AIRPLA...item1e6d07fc52

Might as well have some more just for the sound

Irvine Mills 1.3 9x4

Mills 1 3 7k 9x4 (0 min 12 sec)

IrvineMills (Mk. 1) 0.75 7x4

Irvine Mills 75 (0 min 30 sec)

Boddo's CS Oliver 8x6...with that Combat front end dribble ;-}

Boddo's Oliver.mpg (0 min 39 sec)

Originally Posted by Twin-Stack

In the rocking horse manure category....
http://www.ebay.co.uk/itm/AEROL-HURR...item1e6cfffe5b

"This engine is an early British diesel engine of 2cc displacement produced by Aerol Engineering in 1948 prior to its replacement by the famous Elfin 1.8cc."

And there's also a Gremlin and a 1.8 up for grabs too if you search.

Not many of these 19's around......
http://www.ebay.com/itm/Micromeccani...item27c5c5f948

So that's where Leon got the name from !

Here is the new Parra Wasp. It’s a 1.5 cc or .09 diesel.
If you are looking for a small diesel to actually use and fly your model with, this will make a lot more sense than a used EB of questionable condition.