Turbo Proppin'!

[LeadingEdge]

Turbo Proppin'!
Article written by: Jack Price

We live in a wonderful time for flying the giant scale aircraft. Just imagine a project, be it scale or aerobatic and everything that you need is available from the manufacturers who supply this market. I was chatting to Quique at the Tucson shoot out last year and we were discussing the many options for power plants available. Gas engine suppliers have great reliable powerful engines. The up an coming electric possibilities are many and starting to become more viable. It was only a couple of years ago that Jason Shulman shocked the world of F3A aerobatics with his electric pattern plane. Cutting edge as it was we all new it was the start of a new era. No one then would have thought that a 33% plane let alone a 40% could be also flown on electrics. Mark Leseburg proved that was a coming reality too. Although at this point more bleeding edge than cutting edge it will soon be a viable option for modelers as well. What was missing was the final and ultimate power plant the TURBO PROP. We both thought that it would be neat to put together an aerobatic plane that was capable of flying precision and 3D aerobatics that was powered by at turbo prop motor. I don't know if it was the heat or that clear desert air but we both committed to having such a plane flying by 2006.


With the support of Wren and a great deal of help from Jeff Hollsinger we put together the first Super Yak 54 Turbo and test flew it right after the Toledo trade show. The plane is nimble and powerful and very smooth like an electric. It has some turbo lag which requires getting used to but the lag is not so great that it cannot torque roll and do all the major 3D maneuvers with grace.
It is quiet with only the sound of the prop and whoosh of the jet engine exhaust exiting the second stage stacks. It has a TamJet smoke pump and can create more smoke than Mt St Helens. It creates so much smoke that care must be taken to not loose the plane. It has a 50 oz fuel tank and runs on Jet A with turbo oil mixed in to lubricate the bearings. The engine can turn 160,000 rpm and produce 40 plus pounds of thrust. Static RPM is around 6500 on a 27 x 10 prop. In the air the engine can really unload and the RPM can be much higher unlike the electrics.

We have completed the first part of our goal. We are presently working on the second part of this power system which is a VPP (variable pitch propeller) system for it. This will allow us to feel the full potential of the power that this little 4 pound 8 ounce motor can produce. We plan on having it debut in 2007.
It just keeps getting better and better.

Jack Price for The Flying Giants

[gforce]

SHWEEEEEEEEEEEEET!!!!!!!!!!!!

[Kiwi]

Jack,

Great article and explanation. I have always said that when someone brings a VPP turbo prop power package to the 35% 40% play field the rules of the 3D game will be re written. Quique proved the concept with the fixed pitch version and what he done with the plane in his demo time at the Nall was absolutely phenominal. Normally at the midday displays the crowd is rowdy and full of applause. This year when Quique flew it was more like a silent gob smacked group of people.

I am a well known addict to this hobby and feel really priveledged to be living in an era when RC seems to be bouncing from one leading edge advancement to another almost weekly.

Good luck with the VPP setup. With the weight of the turbine package and the expected weight increase with a VPP bolted to the front it still looks like coming in at a good flyable weight.

I just cant wait to see it in action and if Quique is the guy at the sticks I just know he will reinvent what can be done.

Great stuff and a million thanks for sharing it with us.

Kiwi

[GremlinX]

Indeed... Can you imagine a true vpp on this plane???

[notorious_benny]

Just out of curiosity... how long will the model fly on the 50 oz tank??

Also I have heard that if the turbine has a flame out and the prop keeps on spinning you can lunch the gearbox. Is this true?? If so is there a sealed gearbox possibly coming out on the market.

I would love to set up a model with a turbo prop one day if I can get my finances to stretch that far. Is there a set up currenlty available to power a 40% sized model through an Unlimited IMAC sequence??

[Kiwi]

Benny,

The only really commercially available unit I know of is from WREN and I think Duralite are marketing it in the USA. Thats with a wren 54mm turbine and while it had good power on the YAK Quique flew it would be under powered on a 40% I think.

However you know how the wheels turn mate. Its supply and demand. If they get the 54mm cranking reliably and with a VPP prop then its only a matter of time before they come up with a 60mm or larger flame thrower.

Not sure on the gearbox issue but I dont think its force fed with oil so it should windmill OK. We need to wait and see what comes of that question from the guru's of this device.

The turbine running without fuel might be a different kettle of fish. Its lubed from the fuel it burns so if you flamed out way up and had to windmill back to the ground it might be an issue. I dont really know for sure mate, just guessing.

Kiwi

[notorious_benny]

Jet cat make one as well
I have no idea if its more or less powerful though.

http://www.intairco.net/default.asp?...cat=183&id=688

[jongurley]

I'm not trying to interupt the great thinking in this hobby, because lord knows I enjoy each and everyday I get to fly my birds,, my question is how is the VPP on this turboprop plane going to help it be a "3d Monster" wouldn't the turbo lag play into effect,, I mean I am used to seeing the little foamies with VPP, but how or why would VPP be efficient on this plane,,,,thx

[Reza]

First of all I'd like to thank Jack Price at DuraliteBatteries for sharing with us this info.

Jongurley,

Technology is improving everyday. We have access to so many things that our grand grand parents would've never thought it is possible. Like Jack mentioned they just started the venture and I'm sure they will be improving the system one way or another. VPP is next step and it will make a difference in both torque and speed. After experimenting the VPP, they might find out now they need to work on something else to improve the lag. The lag may remain there but shortening the time of lag can be a big help. It's just matter of time but without a start and lots of R&D we will never get there.

Pushing the limits is what it's about. 30 years ago no one was so privileged to sit on his computer if he had one and connect to millions of people all around the world. I think we are living in a world that is full of suprises

BTW, on Quique's website there is another video of the TP Yak that shows lots of 3D. www.qqaircraft.com

I will feed you guys with more info on how this Turbo engine works. I know lots of you might know but it won't hurt.

Reza
www.duralitebatteries.com
www.qqaircraft.com

[notorious_benny]

With VPP you can keep the turbine wound up and rocket out of a hover 'simply' by increasing the pitch a little. They dont nessecarily mean a reversing of the pitch when they say VPP, that could be quite damaging to the airframe/gearbox.

There would be very little lag at all in this system. It would work a bit like a constant speed prop, maybe we will see goveners to peg the prop rpm at a given value.

The speed of pitch adjustment will be mainly dependant on the power of the servo/servos used to adjust the pitch.

[Sandbag Special]

Neat-O

[3DGE 540]

Now that is just Awsome. I am very lucky to be only 14 and have all this technology, I like to talk to the older guys at my field and listen to the stories of how they couldn't even check to see if there plane was recieveing interferience and the only way to tell was to fly it. And how so many people would crash. It's amazing how fast things change.