Tren 744 Turbine

[tomcarpenter]

what's supplying the fuel and gas valves their power?

the lipo that comes with the kit (2s that plugs into the ECU [that must be stepped-down internally somewhere]) or are they powered from your transmitter.

[kevinww]

The 2s supplied with the motor powers the solenoids, starter fuel pump etc. Receiver is powered from a separate reciever pack, which also powers the FADEC via the throttle connection from the receiver

[tomcarpenter]

sorry for the silly question kevin! It's just that some predator wrens users told me differentenlty (unless the 54 electric setup is different)

[kevinww]

I Could be wrong on the solenoids being powered off the wren pack, but the FADEC is powered by the reciever pack as its all i had plugged in when i set it up.

[Skiddz]

I would assume the 44 is set up similarly to the 54 and I can tell you for a fact that the Fadec will power up with the receiver and the pump/solenoid pack not even plugged in.

[kevinww]

Just got back from a cold and blustery day at the field, must say the 7.6 gears have made an enormous difference. Gear train is so much quieter with the tighter gear mesh, head speed now up around 1780, power now comes in so much smoother and just builds. Its like a rocket ship now, a low pass down the field then throttle up to around 7/8 throttle saw it climb to around 300 feet in a couple of seconds. Just awsomely smooth and all the power you could want, at least til i get really comfortable with it then i can start tweeking the max RPM up on the turbine, as its still currently set at 175k factory setting.

[Drevil02]

Kevin,

As the result of Dave's post, I too switched to the 7.6:1 ratio and have been very happy. My flight times went up, did yours?

I am at 6 minutes of idle 2 flight time with a max RPM of 180k and the stock fuel tank plus a 60ml header and the BVM UAT as a reserve. I did high speed test and got 6:47 out of it before it flamed out. Do yourself a favor and up the RPM, I saw a big difference between 175 and 180.

BTW, I actually blew the tail rotor out on my Tren 700, but luckly was able to auto it down (thanks to Chris at Bergen for telling me I don't need a tail rotor for an auto).So I was just back in the air this past weekend.

MWG

Originally Posted by kevinww

Just got back from a cold and blustery day at the field, must say the 7.6 gears have made an enormous difference. Gear train is so much quieter with the tighter gear mesh, head speed now up around 1780, power now comes in so much smoother and just builds. Its like a rocket ship now, a low pass down the field then throttle up to around 7/8 throttle saw it climb to around 300 feet in a couple of seconds. Just awsomely smooth and all the power you could want, at least til i get really comfortable with it then i can start tweeking the max RPM up on the turbine, as its still currently set at 175k factory setting.

[tomcarpenter]

hi
how is your turbine mounted; just by the 4 os90 nitro mount bolt holes?

did you also support the front end of the engine with a wren strap or whatever (as wren suggest)?

I have a strap but there's nothing really to bolt to on the frame.

I could use a heavy duty tie wrap, covered heat protecting sleeve, that would be very easy and probably just as effective.

[Drevil02]

Wren specifically says you "must" mount the front of the engine. I am currently using a high density nylon strap and a machined spacer.... far from the optimal solution. The tie wrap will work "in flight" but it will NOT hold in a crash and that is where you can bend metal and if you bend any of the structural portion of a turbine, you have most likely just bought a new one as the repair is probably more costly to diagnose and repair.

I am designing a high-end Trex conversion kit that will include machined carbon frames, machined aluminum (or carbon, still testing this) engine mounts, the required gear train, and other hardware necessary to do this conversion the right way. It is not simple if you take into account C/G, weight and durability. I am hopeful to have the first 5 prototypes out to select folks before Christmas (the first two are already spoken for).

mwg

Originally Posted by tomcarpenter

hi
how is your turbine mounted; just by the 4 os90 nitro mount bolt holes?

did you also support the front end of the engine with a wren strap or whatever (as wren suggest)?

I have a strap but there's nothing really to bolt to on the frame.

I could use a heavy duty tie wrap, covered heat protecting sleeve, that would be very easy and probably just as effective.

[tomcarpenter]

this is no ordinary tie wrap I have Crashes do happen of course, but I always do thorough preflight checks on my expensive heli's.

The trex frame doesn't give you many choices to support the front of the engine.

I am very happy with my frame conversion, but will keep 2 eyes on any frame kit developements.

[Coolice]

Originally Posted by Drevil02

Wren specifically says you "must" mount the front of the engine. I am currently using a high density nylon strap and a machined spacer.... far from the optimal solution. The tie wrap will work "in flight" but it will NOT hold in a crash and that is where you can bend metal and if you bend any of the structural portion of a turbine, you have most likely just bought a new one as the repair is probably more costly to diagnose and repair.

I am designing a high-end Trex conversion kit that will include machined carbon frames, machined aluminum (or carbon, still testing this) engine mounts, the required gear train, and other hardware necessary to do this conversion the right way. It is not simple if you take into account C/G, weight and durability. I am hopeful to have the first 5 prototypes out to select folks before Christmas (the first two are already spoken for).

mwg

Hey,

I'm also very interested to see and hear about this conversion you're working on, as this will turn a Trex700 it into a more specialist Turbine airframe which will give it the edge it deserves.

Ian

[Drevil02]

I will post something as soon as I have something worthy. I am VERY excited as it seems to be a great conversion platform (flies great, cheap to buy and more importantly repair...).

Michael

Originally Posted by Coolice

Hey,

I'm also very interested to see and hear about this conversion you're working on, as this will turn a Trex700 it into a more specialist Turbine airframe which will give it the edge it deserves.

Ian

[kevinww]

Had a great day out with the 744 yesterday, decided it was time to stop babying it now that the gearing is sorted out and i have got a better feel for it. So flew a basic routine of stall turns, loops, flips and rolls.

Loops you can make as big as you like, single and multiple rolls were perefectly axial in either direction, and the flips were fairly sedate and didn't deviate in location, stall turns were a breeze and you can really get it to hussle across the field when you want and throughout the MW44 performed fautlesely.

[kevinww]

Back in 2009 there was a video taken of my maiden test flights with the Tren 744 which has just been put up on the tube, its taken a while, but here it is.

[ame]http://www.youtube.com/watch?v=rYwl7KfsoHQ[/ame]

Nothing fancy as it was the first flights and was just checking things out.

[cbdane]

I'd love to watch a "music free" version. That is, other than the wonderful music of the turbine exhaust.

[kevinww]

Its not my video, so not really much i can do about the music. Just pleased its been put up on the tube so I can finally show it off, although the livery has changed since those first test flights.

[Aussieheliguy]

How many hours have you got up on your engine. Mine has moved past 45 hours, getting close to the magic 50 hour mark.

[kevinww]

No where near what you have, probably about 12-14 hours.

[kevinww]

Originally Posted by cbdane

I'd love to watch a "music free" version. That is, other than the wonderful music of the turbine exhaust.

Here's a more recent video where the only sound track is the turbine.
[ame]http://vimeo.com/26965429[/ame]

Currently thinking of converting it flybarless and stretching it to an 800.

[Aussieheliguy]

Yep done that to mine a while ago, now has a slower h/s ( around 1600 rpm ), more like a larger heli now. I went with CGY750 and NHP 800 mains plus 115mm Edge tails.