GT Propeller's blade on Hartzell's hub

[dilamipo]

Dear Vansairforce members greetings from Tuscany Italy

After 3 years of intensive work finally my RV7 with one Lycoming O360A1a ,180 HP driving a constant speed prop and analog avionics had airborne on the 25th of March.
After the first flight of about 20 minuts little cruise and some touch and go were made. All went well.
The performance noted solo and half fuel are :
Take off distance about 100 meters,330 ft.
Climb rateo 2000 FT @ 100 kts
Economic cruise was 160 kts @ 2300 rpm,23 MAP.

The prop I have adopted is the Hartzell HC2YK upgrade with wood composite GTV24HY blades.
Company suggested 73” diameter.
Compared the original stock Hartzell the GT blades reduced weight of about 10 kg,20 pounds with very low inertia moment. Much appreciated on take off !!
Very smooth, expected dynamic balance by factory shortly.
See company link,

http://www.gt-propellers.com/hartzell-propellers.html

I’ll be more precise in performance after next flights.

Thanks Umberto and Vans for this fantastic aircraft.

BD0B-FC426901BE76-601-000000A9EDB8727A_zps201cc320.jpg[/IMG]

[ccsmith51]

Congratulations, beautiful airplane!

[Toobuilder]

Interesting! That may just give new life to the scores of perfectly good, but "worthless" Hartzell hubs out there. With the massive reduction in inertia and change in harmonics, it's logical to assume the (extremely rare) cracking issues would go away. At the very least, the change in blades makes it a whole new ball game.

If the blades perform better than the metal ones, I think there's a future there.

BTW, doesn't Whirlwind use the Hartzell hub?

[rocketbob]

Originally Posted by Toobuilder

BTW, doesn't Whirlwind use the Hartzell hub?

Its because the Hartzell hubs have ground split bearing races which are harder to manufacture. The McCauley hub is easier to machine and source parts for. But the Hartzell hub is simpler in design and easier to seal.

I would want to see before/after performance numbers before I would come to any conclusions, along with the price. The tip chord is very wide which is fine for static thrust but most propeller designs suitable for RVs have a tapered chord which is going to be more efficient at cruise.

[Toobuilder]

Originally Posted by rocketbob

...I would want to see before/after performance numbers before I would come to any conclusions, along with the price...

100% agree. Any new blade or propeller will have to buy its way onto my airplane based upon performance or some other viable metric. Being "the latest thing" is not a legitimate metric. However, I think that competition is a good thing, so this initial (if somewhat unknown) step is definately encouraging, even at face value.

[6 Gun]

No whirlwind does not use Hartzell hub.

[Toobuilder]

Really? Ok, thought I read that... Who's hub do they use (or is it thier own)?

[6 Gun]

If you go to the Whirlwind site it looks like a McCulley knock off.