First Titanium Autogyro flys in the USA

fara

AR-1 gyro manufacturer
I guess the question to ask is everything else being equal, is static thrust one indicator of a props performance or not? In other words setting a fixed prop on a tandem pusher gyro, for a Rotax 914 to deliver say 5400 RPM at max RPM on the ground, is static thrust not a measure that can be used to compare two props at least at those parameters? If not, why not? I understand hat this does not automatically mean the props will be comparable in all situations, but it would seem reasonable that static thrust can be used as a reliable starting point. I guess the next question to Fara is: Is there data to show that there is no connection between static thrust and other forms of measurement or is there a linear relationship? Do prop manufacturers have this type of data?
Yes they are a measure of which prop produces more static thrust for sure. What I am saying is that that measure is a bit useless and unfair if you are looking for a good prop for say your MTO. Even though gyroplanes are slow they are not flying at 30 to 40 mph
 

MadMuz

Newbie
I find the best thing a static thrust test is good for, is to see that you have the prop pitched correctly, so the engine doesn't over rev, or struggle to reach the revs you want. However, if you want a motor, say a 582 to max out at 6800 rpm, you would have to set the prop while the machine is tied or on the trailer, stationary, to about 6400 rpm.... if you set it for 6800 on the trailer, it will over rev in flight at wot.

The thing is that people can cheat a static thrust (pull measurement) test by setting the pitch for best static thrust.... but that wouldn't be best in flight...then re set the pitch of the prop again before flying.:yo:
 

JAL

Member
I find the best thing a static thrust test is good for, is to see that you have the prop pitched correctly, so the engine doesn't over rev, or struggle to reach the revs you want. However, if you want a motor, say a 582 to max out at 6800 rpm, you would have to set the prop while the machine is tied or on the trailer, stationary, to about 6400 rpm.... if you set it for 6800 on the trailer, it will over rev in flight at wot.

The thing is that people can cheat a static thrust (pull measurement) test by setting the pitch for best static thrust.... but that wouldn't be best in flight...then re set the pitch of the prop again before flying.:yo:
But even using static test to set the prop pitch doesnt work that well either as it doesnt account for the forward movement through the air and the subsequent change of AoA of the prop blade so therefore pitching your prop based on a static stationary test is only optimising you thrust for being stationary.

To pitch your prop and/or optimise the thrust (at given airspeed) require empirical flight testing so that the optimal pitch can be calculated.

Static tests are not necessarily the best way to compare fixed pitch props because the prop pitched for maximum static thrust will have a course pitch compared to the one optimised at 60 knots airspeed.

A static test will say the former has more thrust than the latter but it will be reversed at 60 knots, it just depends where you want the engine/prop combination to be the most efficient.
 

TAGNA

Titanium Autogyro
The Titanium Explorer will be at Mentone. The price has dropped to just over 64,000 for the 912 model and this includes build assist. This might not last for to long and is based on the Ausie Dollar. The 914 is just over 73000.
We hope you all have a great time and we will enjoy meeting many of you!
 
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