I think cheeks like in a basic trainer are much more beautiful then most beautiful cowl you can imagine around the motor section of an airplane.

I’m saying this because there is nothing uglier then an airplane that was designed with a cowl and then the cowl broke.

Questions: how bad is the influence of the fire wall and cheeks on flying characteristics of an airplane or what price am I paying leaving the airplane with cheeks only?

Thanks
Alex

With a trainer, no price. The difference in speed will be so small you would probably have a hard time measuring it, and in ordinary flying you won't even notice it. The cowl on a trainer is there for looks, period.

I had Ultra Sport 60 or TF contender in mind when I posted this question.
I’m asking this because cowl is a trade off to an easy access to the motor.

Thanks
Alex

Can't be sure with that one, as I've never tried that sleek a plane without the cowl. I still doubt that it would matter much. The cowl on an Ultrasport has a big hole for the cylinder head to stick out of and there's a muffler out there in the breeze, too. So how much difference is a little more drag from the firewall going to make?

Alex, I'm currently flying a Kaos which is an Ultrasport with cheeks and without a turtle deck. I've also lived with the aggravation of a plane with a faired in nose very similar to the US60 only it was a 40 size plane, thus even more confined. It was so slippery I had to take a lap at 1/4 throttle to slow it down for landing!

The large canopy, thick wing and fixed gear of the US60 means you already have a 'dirty' plane from a high speed standpoint. If the plane were mine I'd build it faired per instructions but I have to admit for access, cheeks are nice. Nose gears are notorious maintenance magnets and a faired in nose can make it frustrating. With that said I personally prefer a faired in nose over cheeks (or cowl) on all but the most utilitarian airplanes, both for looks and profile drag. One of the most important streamlining areas is at the nose of the plane near the prop.

Thanks guys,
CrateCruncher you got my point, i forgot how much trouble i had with the trainers nose gear, im building my US60 with a nose gear and want to cry already because of the repairs i can see coming...
i'll order another wing kit - profiles and will build another wing with retracts.
so fast you get used to good things like tail draggers.

Thanks
Alex

cross section of the fuselage means little
unless you completely blank out the prop -like scale models of GeeBee R1 craft
The closer a large dia. flat plate is located immediately aft the twirling prop, the lower the thrust will be .
You can do all kinds of cowl shapes on our small models and never make 2 cents worth of difference in performance.
for max efficiency you will extend a spinner and prop as far as possible ,from the larger cross sections of th fuselage
sorta like the spinner /cowl on turbo props.
here is an example