Current Projects - Fury 55 - GT15

[Universe]

I don't want 9 HP but just the power that was advertised 2.76 HP it's over any 60 size glow engine.
what's the total weight and will you run it with higher rotor speed ?
I can compare the GT15 with an old OS 32 watch video.

[ame]http://www.youtube.com/watch?v=srdrK6wV6M0[/ame]

[carey shurley]

the model as shown is 9.5 lbs and it has some heavier than necessary parts in it.

when the manufacturers offer actual kits (not using existing parts as I did) they will be able to get some more of that weight off

higher head speed - not with this gearing and if you've been following it wasn't happy with lower gearing

[James Kovach]

Let me make sure I am getting everything straight you have said so far.

7.4:1 Ratio with 640s = Bad

7.9:1 Ratio with 640s = No Good because......

Flight video above is 7.9:1 Ratio with 620s?

The 7.9:1 Ratio is still not the right one and if I remember reading correctly, in another thread you said 8.2:1 would be better.

Based on that video and the fact that 8.2:1 would do nothing but drop the performance level even more ( lower head speed )... IMO, that engine is really worth messing with.

[martin_]

It's definitely not an electric powered heli, but for that motor size and flying time it give, it's ok, and definitely much much better than in a 700.

That motor will need to be piped to get its full potential.

[kva]

Congrats with great flying heli! It was really respectable flight.

I think here is a slight issue with incorrectly set expectations and I am not sure who's fault is that.
Then were is so much effort invested into the conversion and heli is put into Bobby Watts hands everybody expects WOW results. However it looked like WOW was missing.

I agree this heli differ from 700 much. It doesn't bog but it is heavy for 600 size. I am not convinced it is much much better than 700. We might achieve similar results lowering pitch angles from +/-13 to +/-11 for 700. It would be much cheaper modification.

It is a pity that motor operation was not 100%reliable during Bobby's flight. Motor had choppy sound on rapid descents. It seemed like governor low throttle level was too deep or governor gain was too high. It sounded like it was throttle control oscillation. However that is just my observation and it for sure wouldn't affect max motor power.

Anyway I am very happy with successful results of the complex project.


Regards.
Kva

[carey shurley]

in another thread you said 8.2:1 would be better.

you're mixing apples and oranges, I said 8.2 is better with 690mm blades, which was on the Raptor G4, a different helicopter. I have a new set of gears to try that model with 8.53 now when I get around to it

because of its smaller displacement, the motor can be loaded easily at taller gear ratios. A shorter ratio becomes a dance because the motor has an RPM cap in terms of power and most of the helicopters have a particular head speed that they tend to perform the best with. Gary Wright likes to fly his electrics around 1100-1200 RPM. It could be geared around 9.5:1 and easily meet that. But the main reason to turn the electrics at lower speeds is to get a longer flight time. With a typical glow sized tank, this motor will run at least 15 minutes and probably longer so thats not really a requirement.

I prefer to fly the Fury 55 with the 640's, Bobby preferred the 620's

7.92 is the shortest I can run with this setup, my next option would be 8.26 but that will require a lot of modifications to the model including a new set of frames and lower the max head speed to about 1875-1900. That might be interesting with a slightly longer model and a set of 660mm blades.

[carey shurley]

It sounded like it was throttle control oscillation

you are 100% correct on this. I haven't found the right governor/throttle setup to make that go away yet. It is much better than it was initially though

[Universe]

Originally Posted by carey shurley

the model as shown is 9.5 lbs.

ready to fly with fuel ?

[Billme]

I thought it was great myself for stock, there is more to come I'm sure

[ben_beyer]

I'm not a hardcore 3D pilot so if MA comes out with a Whiplash 6G as mentioned, this would be my next heli hands down. A 550 somewhat interests me except for the low flight times. I would rather stick with a 50 size light gasser.

[spacecowboyz]

Will their ever be a conversion kit available? i like the way it flys in the video. Nice job Carey

[billp]

ignoring the few negative comments about the flight performance of your GT15 project, i feel you have done a great job on it !!!
mr. watts demo flight of your machine shows just how well the OS engine can power a 550 - 600 sized bird.
i hope OS engines has thanked you and complimented you on your work and determination in bringing the fury55 to its current success.
i wish you more success in any future projects you have planned, please keep us informed with posts of any new ideas you have brewing in your workshop !!!

billp

[kva]

Hi Carey,

would you be able to post a picture showing temp sensor fixed to the motor? In some post you said you usually measure the temp around the bottom of the cylinder fins. Could you take a look at my picture to check if measuring point is similar to yours?

While my first GT15 motor is being sent to OS for the failure investigation, I have bought second motor to play with. This time I want to be more careful then measuring temperature and RPMs.
Here are my temp and RPM graphs form the third break-in tank. Temp stays within 50-60C (122-140F).

I have also crosschecked temperature with IR thermometer. Eagletree measurement looks to be precise.
However I found that temperatures on the head are at least 20C degrees higher. Is it sensible to move sensor up near the head?

Regards,
Kazimieras

[carey shurley]

I'm using the Futaba temp sensor which is a loop. I've got it looped around the case but at the very top, basically I pushed up under the cylinder head so its measuring on the exhaust side at the very top of the case.

I'll try to take some time to get a pic, I've been getting a goblin ready to be converted.

[brw0513]

It is a pity for us that the EagleTree Cylinder Head Temperature Thermocouple Probe Kit shown on this page only works with their Flight Data Recorder and not the eLogger::

http://www.eagletreesystems.com/Plane/plane.html

There is a TTO temp gauge that might be useful:

http://trailtech.net/tto_temperature.html

I'm very keen to hear more about this Fury 55G.

[brw0513]

Hi Carey,

Your Inbox is full so thought I'd post here to reach you.

I can't shake the idea of fitting a GT15HZ into a Fury 55 frame but getting parts might now be a problem.

Keen to know if you think this is still a reasonable option?

Are the Whiplash donor parts parts limited to Nitro Fan, hub, shroud, clutch, bell, pinion, bearing block and engine mounts or is there something else required?

Am I right to think the converted airframe will have two auto clutches as you mentioned previously?

What pinion did you use to settle on 7.92 with the 640 RT blades i.e. a Fury 55 pinion or a Whiplash pinion?

Thanks.

[Rudy]

You do understand that MA closed down on March 1st. There are no new parts being made and the parts supply is drying up.

It would be much wiser to find some other kit to convert.

[Rahulgaba]

Does the GT15 just need 700 size mount? I have a 600 bird with a 700 engine (nitro) stuffed in it... Wondering if GT15 will fit that mount. I have 7.9 or so gear ratio.

[carey shurley]

the gear ratio you have is probably okay

it needs a 700 class cooling system. The Whiplash system worked REALLY well which is what I had put into this conversion

[Rahulgaba]

I'll see if I can get the whiplash fan and shroud to fit the frame. Very interesting. That'll mean I'll have to keep my nitro whippy parts as a backup