New GT Propeller

I've finally installed my new propeller.

As you can see from these images I'm using our old spinner assembly but I may end up developing a new spinner as well.

The 74 inch propeller built by GT Propeller is 9,5 kg lighter than the former Hartzell. It is built out of wood and carbon fiber and after the engine test on the ground I must say vibration-wise it's a different world.

As you know I have a modified IO-360 developing 212 hp (high compression piston and so on...)


GT Propeller has studied and optimized the propeller blades for the speed, weight and engine rpm of my Falco. The quality and craftsmanship is simply astonishing! I'm so happy. It's probably the best improvement to my plane since I built it. You can't really imagine the vibration reduction.

On the ground I've really appreciated the smoothness feeling.

Service and the company feedback is incredible, let me say from a fashion point of view, it's tailor made!

I'll get back to you shortly with the results of the first flight test.



Today I've done a few flight tests, and I'm satisfied.

The main quality and improvement is certainly smoothness! While flying I was thinking how much I've flown missing this sensational lack of vibration. Noise has changed and the frequency is much lower, during a low pass at more than 200 kt I've been reported that the primary noise was aerodynamic.

Speed: It's too early to compare, today due to rain and very low ceiling I had to stay at 1200 feet (with a density altitude of 1410 feet) at 28,8 of map and 2690 rpm I was getting 192 kt, but it's really a rough number. I'll come back with a full report after I'll have set RPM.

Honestly I'll never be totally satisfied about speed as it would mean I stop my speed research, and I guess we are all speed alcoholics...)

One very positive advantage is the reduced torque during take off -- the 9,5 less kilos up front spinning -- shows very well along -- once again -- with the almost non-existent vibrations! Just to give you an idea I had to use half rudder movement compared to the Hartzell prop.

I've already spoken to GT Propeller, and they will send me new blades after I'll have finished the flight test collecting all the data. The new blades will be further optimized.

CG has improved and you can easily feel there are 9,5 kg less on the nose during approach and landing. (On my plane I've also the added weight of the Christen inverted system on top to the IO-360) so it was nose heavy.

I must say overall I'm really satisfied. It should be a must on all the IO-360 Falcos. For the first time today my Falco has resembled me the flight characteristic of the original ones.

Will write you more as soon as the weather will improve.


I've flown again with the new propeller, and I've gained some interesting data. The propeller performs very well at high speed but not so well immediately after the rotation and until 110 Kt, then the climb rate increases compared to the Hartzell. Max speed has gone up 4-5 Kt but due to turbulence I'll check again on Wednesday as I'll fly to GT Propeller to do some adjustment and trim away two inches in order to check if it goes even faster.

They are actually designing the second set of blades which I'll install as soon as they are ready.

As you can see from the photos I've the right main gear door that opens (above 170 Kt) and I've not solved the problem yet, I'm thinking to install a NACA fairing ahead and behind the wheel in order to smooth the air flow and avoid the door opening.

There is still room to improve the performance of my tiny old Falco!



Alex and Paolo Tonini trimming one inch. Waiting for the new blades. I felt 74 inches was too much.





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