UMS 7-160 on 87” Ziroli Stearman.
 

Do you think this is just too much power? I’d like to have a 7 cyl.
The plane may come in at about 40”#. maybe a bit over with this radial.
it pulls about 36# wide open with a 28x10 prop, weighs 9.5#, and has 10.2 horses.
the next smallest radial in the UMS line is 6 horse, weighs about 6#, and has a maximum thrust of about 20# with a 24x10 prop.
I am primarily interested in flying scale.
The 87” Ziroli Is a heavy plane.
I

I would like to know if a G 38 or Q 42 would be strong enough. J

Ziroli Stearman power
 

Those engines would suit the 77” 1/5 scale perfectly.
I don’t think they would be a good match for the 87” model. For the 87 incher the plan calls for a G62.

Curious, did you ever installed the UMS 7-160 on your Stearman? If so, I would like to know your opinion of the UMS radial engine. I am currently building the Balsa USA 1/3 scale Stearman, and would like to consider the UMS 260 as the powerplant. Unfortunately, I am not finding very many comments from people currently using the UMS radials for their models. Prices of the UMS radial engines are very appealing, but just not sure how reliable/durable these engines are. Would greatly appreciate your opinion.