Since you plan to physically test an existing structure, I guess there is no need to worry about the engineering involved in designing a structure to withstand those forces.

180 deg in one second is 30 rpm.

30 rpm is 1800 revolutions per hour.

1800 revolutions in one hour = 250 miles.

1800 * 2 * pi * r = 250 mi.

solving for r,

r(adius) = 116.71 ft (35.57 m).

a = v^2 / r

where a = acceleration, v = velocity and r = radius

250 mph = 111.76 m/s

a = ((111.76 m/s)^2)/(35.57 m) = 351.15 m/s^2

1 g = 9.81 m/s^2

351.15/9.81 = 35.8 g

That's a lot of g's, but not unreasonable, if one has ever watched a formula 1 model airplane race.

Remember, there is at least a 50% safety factor built in to small full-scale aircraft. So the structure must not fail up to at least 54 g if you follow that practice. With a model and no telemetry, I would feel better with a 100% safety factor, or 72 g!. Don't forget to consider the loads on the stab/elevator, and the fuselage and engine mount.

DISCLAIMER: I am not an engineer, and I'm not liable if your plane breaks anything, or hurts anybody. These calculations and $3.50 will get you a cup of coffee at Starbucks!


Good luck, and be careful!


P. S. Dick, are you reading this? A few minutes work on a scratch pad can provide data for ground testing that might prevent an in-flight structural failure. I'd sure rather have it fail on the ground during a test than in the air!