Gonzalo38

I'm ready to do the maiden of my turboprop Marchetti equipped with a Jetcat SPT5 and I was wondering if you guys have changed the preset values of the turbine.

While exchanging some info with Bevar, he told me that he limits his propeller speed to a max of 7750 rpm in order to protect the reduction gears. Is anybody else doing these ?

Maximum rpm's set at the factory are around 8250 rpm so I'm wondering if with this reduction you are loosing a lot of performance.

My main turbine maximum rpm's are set at 165.000 rpm's.

Jetkopter

My Feedback: (1)

Thrust: 55 lbs with 27" prop at 7,0000 RPM

Weight: 4.9 LB, incl. starter

Length: 15.25 inches

Turbine RPM Range: 50,000 - 165,000

Propeller RPM Range: 1500 - 7000 RPM

Exhaust gas temp.: 580°C -710°C

Fuel consumption: 8 oz per/min at full power

Fuel: Jet A1, 1-K kerosene

I had mine in a turbo raven, if you run the prop too fast it will let you know as the tips go supersonic! Sounds cool but with all that thrust dialing the rpm down should not be a problem

Gonzalo38

Thanks Jetcopter...... but if the specs say that propeller rpm's should range between 5.000 to 7.000, why it comes set up at over 8.000 rpm's from the factory ?

Springbok Flyer

Gonzalo,

I have been flying my Tucano with the same JetCat SPT5 v3 for about a year now. I use the Biela 24x12 3blade prop and the standard settings as the turbine came from the factory. Absolutely no problems - it is a great combination.

Cheers,

Jan

martin_wam

I contacted Jetcat about this and they said it would not be a problem to dial the turbine up to maximum, which I did with my Tucano.

I wonder why it isn't dial up to max from the factory.

Gonzalo38

Martin:

What are the maximums that you are using ?

pilot tw

just testing my spt5 v3 today


http://v.youku.com/v_show/id_XNTY3Mzk0MDI0.html

Gonzalo38

Anton:

Is that Pilatus a new development from Skymaster ?

What are the maximum rpm's that you are getting on your prop ?

pilot tw

yes, this is new PC-21 prototype, i have no chance for check the rpm, but the power of spt5 very good when i maiden the prototype PC21 today, here is maiden video for PC 21,


http://v.youku.com/v_show/id_XNTY3NDA3NTIw.html

Gonzalo38

Anton:

Congratulations on your maiden. It is really good to see that you are working hard on developing new models....... specially ones that are not ready available in the market. There are not many airframes available for turboprops so this should be good news for a lot of people.

bevar

My Feedback: (27)

Hi Gonz,

I'd have answered sooner but have been out flying the heavy iron today...oh well.

A few things to know. The SPT come set up for a 2 blade prop which turns higher than a 3 blade.

The standard Biela 24 x 12 3 blade prop is only rated for 8,000 RPM. You need the "Turbo" 3 blade prop to get a 10,000 RPM limit. Either way, that's too high from a prop efficiency aspect to turn...you are just making noise at those elevated levels.

I set the prop to 7,750 RPM with the 3 blade because honestly it does not need to be any higher. You can only pull 6,000RPM static so why abuse the gearbox or risk blowing up the prop (I run the standard prop).

I limit the turbine RPM to 168,000. The reason is that the Max Limit is 170,000 RPM and if set to this number in flight it will actually hit 171,000+. I again drop the limit just a bit to take it easy on the turbine.

I now have 20 hours on the gearbox and have not had a single issue with it. It's as strong and tight as the day I took it out of the box and it has not had a thing done to it. JetCat rebuilt the turbine section for me under warranty last month because I simply wore it out but did nothing to the gearbox because it is still perfect.

Kudos to Bob and his crew for the excellent service and you will love the reliability of your SPT V3 Turbo Prop...it's the best baby!

Saludos,

Bolivar

Gonzalo38

Boli:

Thanks for the info. It is much more clear for me now. Will keep it at 7,750 rpm and see how it goes.

Carbon-Customs

the prop tips dossent go supersonic....

the tips just makes some turbolence which go supersonic, like a whiplash...