Martin, I have an Enya 50ss and when I was breaking it in I also was breaking in a ST51. There was no real attempt made to document anything at the time but the tach at the end of the run in period said the Enya was a little stronger,'Now that would not be the case if perhaps you had a reworked ST51.
Sorry i can't be of more help.
dennis

Thanks Dennis for your reply. Now that Randy is selling Enya Engines we will be hearing more about them next year.

I have done some flying with one and it has a pretty solid run from start to end.

I think the Enya SS50 will come to proof it self as a better engine then the ST G51. It is lighter and built with better materials.

Just for testing, we were able to bolt an Enya SS50 on a old plane that had a ST 51 before without any modifications, just the tank height was different. We didn't flew it enough to tell how good the SS50 really is pulling a 60 size plane. But so far so good.  It felt very strong pulling the old heavy plane with a TopFlite 13x6 Prop. Perhaps a 13x5 would work even better on this engine.

I also did a few flights with the Pathfinder using the Enya SS50. I used the original muffler and the CG come just right on. Tried the  Rev UP 12x5 and a Bolly 12.5x5.5, 10% Wildcat fuel, Enya 3 plug. The Flight was just awesome having so much extra power >big grin<. The Engine ran very constant, like a 4S.

Martin

                                       A            B           C           D           E           F           G

Enya              50SS       0.14       1.35       0.71       1.67       1.93       2.00       3.23
Super Tigre      G51        0.14       1.38       0.76       1.65       1.95       1.97       3.24


A= Mounting Hole Diameter

B= Engine Width at Mounting lugs (Crankcase width excluding engine lugs)

C= Fore/Aft Distance between Mounting Holes (Center to Center)

D= Width wise Distance Between Mounting Holes (Center to Center)

E= Distance From Center of Front Mounting Hole To Face of Thrust Washer

F= Overall width of engine mounting lugs

G= Overall Length From Backplate to face of Thrust Washer

Very Close.