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HelicopterTurbine Helicopters › Turbine 3D
04-03-2005 03:58 PM  13 years agoPost 1
dnp

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DFW Texas

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Why is no one yet doing violent 3D with turbines? If it is turbine lag, could'nt that be dealt with with the free turbine having variable nozzle guide vanes controlled by its own governor, and the gas generator with its own...or perhaps both governors intermixed? Or is that adding complexity too early in the turbine evolution? Am sure looking forward to getting a turbine heli once I see that they are indeed fully capable of "gittin it on"

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04-03-2005 04:37 PM  13 years agoPost 2
Peter Wales

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Orlando Fl

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Because violent 3D is done by people who cant fly properly and just bang the sticks around. Turbine owners have more skill and sense

Flame suit on

Peter Wales
http://scalehelicopters.org

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04-03-2005 08:53 PM  13 years agoPost 3
Peter Wales

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Orlando Fl

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Weeelll this question has been asked and answered so many times before.

People are doing 3D with them and it will get more prevalent, but a 50 Raptor will always be more violent than the turbine heli cos its smaller and lighter, so no matter how radical the 3D gets it will never seem as violent as a smaller lighter heli, even though it is doing the same stuff.

Alan Szabo is doing super smooth 3D with his Odyssey, and it definitely is not designed to do 3D. It can be done.

Its like asking why a truck with a 500 HP motor isn't as maneuverable as a Ferrari with a 400 hp motor.

Peter Wales
http://scalehelicopters.org

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04-03-2005 09:49 PM  13 years agoPost 4
wolfdad

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Southern Maryland

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Dang Greg! I think Peter, bless his heart, said it like it needs to be said.

wolfdad sends....

"There are those who have...and, those who will" IRCHA #2117, AMA #70068, Turbine Waiver #105

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04-03-2005 10:37 PM  13 years agoPost 5
dnp

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DFW Texas

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So...A turbine heli is or is not capable of performing the full range of 3D manuvers? Or at least, the helis on the market so far?
And turbine lag really does'nt matter for aerobatic heli manuvers?
Is it way too early to be asking these capability questions?
And another thing....an airframe is an airframe...simply because it houses a turbine engine does that justify a price difference between a nitro version and a turbine version, albeit perhaps a tad larger in size, that may be lots of hundreds or thousands of dollars?
Turbines are probably going to end up being the "Power" 3D helis, I think.

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04-04-2005 12:16 AM  13 years agoPost 6
vetrider

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Daleville, AL (Ft.Rucker)

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90% of why a turbine is used in a REAL helicopter is RELIABILITY. Power comes at the expense of heat. The more heat the less the reliability of a turbine.

It's a give and take and Alan can do what he does because he is as Peter said "SMOOTH" with the turbine.

Nolan

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04-04-2005 12:36 AM  13 years agoPost 7
wolfdad

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Southern Maryland

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dnp,
We have only "scratched the surface" when it comes to turbine-powered heli's. Vetrider's comments, along with Peter Wales' are absolutely correct. If you asked me if you will ever see a turbine helicopter do the "snatch and grab" style of 3D flight, I would have to answer with an "I don't know at this point." I am not particularly enamored with that style of flight anyway, however I can tell you that turbine-powered helicopters as demonstrated by both Alan and Jason are perfectly capable now of most aerobatic manuevers. BTW, dependent on exactly how the Wren 54 is set up in the FADEC, "turbine lag" can be minimized to such an extent as to be almost negligible. Smooth, powerful and fast are the three turbine by-words that will come to be known in wider circles during this year.

wolfdad sends....

"There are those who have...and, those who will" IRCHA #2117, AMA #70068, Turbine Waiver #105

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04-04-2005 05:11 AM  13 years agoPost 8
Branzzz

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Singapore

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i'm very interested in this topic too. do correct me if i'm wrong, but isn't agility based on disk loading? isn't that why a 90 will perform better than even a 50 size, because it has slightly lower disk loading? considering turbine helis can spin much larger disks than a 90 size, would it be possible to get to a point where the disk loading of a turbine heli matches that of a 90 sized nitro?

Raptor 50V2
OS 50SX-Hyper
GY502/9253
Hitec 6975
Airtronics ERG-VB
JR 3810

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04-04-2005 05:15 AM  13 years agoPost 9
TMoore

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Cookeville, TN

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Watch Bob Johnston with a Turbine powered Cuatro. Looks OK to me.

TM

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04-04-2005 09:06 AM  13 years agoPost 10
NEIL2-UK

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UK - South East

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Turbine 3D... or Not?
Hi All who have interest in this subject

Turbines can throw 3D manoeuvres... as already said in this thread, the Bob Johnston manoeuvres with the Cuatro (whether Wren or JC powered) have shown that it can be done.

Dean Jackson in the UK could 3D the TT-Cuatro just as BJ has done in the past...

Ken Gale (scale specialist - UK) flys his TT-Cuatro as if it was a scale heli... smoothly and with slow head speed. This was to get used to turbines (flying since September 04) and now it is sitting in the Vario Bell230 conversion.

Airframes are not so expensive, but the turbine system is... the turbine can deliver raw power or can be tuned down to give just torque with low speed and lots of blade pitch. Gearing is more flexible and does not need to be so precise in setup as other engine power systems.

Ken Gale flies TT-Cuatro at around 1380rpm... but on the same gearing it can be flown 3D with 1800+rpm. Both speeds on a set of 795mm BBT blades.
TT-Stormfire is flying 720mm blades. The same engine system flys the 1/4 Scale JetRanger on 2.5metre blade disc... but with a different airframe system and obviously this is geared to a lower headspeed.

The power does not suffer lag problems, when setup correctly... and can be a much more flexible power source than the Gasser or ic-nitro engines. Most people fly and setup withpitch/throttle curves to suit the turbine... and with the two-stage system you can run near constant speed and stable power delivery.

A well setup turbine two-stage system such as the Wren based systems deliver virtually no residual thrust, and run at low temperatures. The single stage systems have thrust problems which require a more careful installation, and the heat in the system is generally much higher and can cause problems in the scale applications.

Good Luck with Turbine Flying

NEIL

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04-04-2005 02:21 PM  13 years agoPost 11
wolfdad

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Southern Maryland

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chopper jockey,
I would do some more homework prior to making a "hard" statement like that. There is an abundance of very conclusive evidence that turbine power is far more reliable in full-size helicopters than piston-power. In fact, I am unaware of any remaining piston-powered helicopters in the US military inventory. Additionally, both vetrider and I are both in military RDT&E communities where the homework on this particular subject is daily fare. Were I you, I wouldn't jump too far off the curb on this one....

As heli_jack just said....2 cents.

wolfdad ends...

"There are those who have...and, those who will" IRCHA #2117, AMA #70068, Turbine Waiver #105

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04-04-2005 03:14 PM  13 years agoPost 12
Gary Travis

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Utah

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First we are talking about model helicopters, I would have to agree with Wolfdad. It would be hard to disagree as he has a wealth of knowledge on both the model turbine two stage as well being involved with full size turbines in his employment.
I am presently flying a two stage Wren system and also have a JC single stage, Wolfdad has had a JC until recently and now flys the 2 stage. There are a few more people in the US at present flying the Two stage Wren system, we all converse on a regular basis to try and share the info on these. Neil at TT has stated that the Cuatro will fly 3d as it has been done by various persons in the UK. Neil hass spent alot of time and effort to get the Cuatro as well as his other machines to this point, and is more than happy to share this info.
That being said, I can say that the 2 stage can be flown in 3D mode and the headspeed with a little tweaking can be brought constant. Also shortly you will see a govenor for these. Between Neil, Wren, Wolfdad, Greg Alderman, and myself I see the capabilities of these machines getting better at a rapid pace.
I have flown most of the turbines available and in the plan on flying different madels as they becone available, I have seen great leaps lately and expect to see more due to the constant development by all involved.
Gary Travis

Bergen R/C Helicopters Duralite Batteries DJI Innovations Magnum Fuels Wren Turbinesl

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04-04-2005 03:52 PM  13 years agoPost 13
dnp

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DFW Texas

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Some excellent information from all who have answered. Thank you.
One final question...The Bergen turbine looks very interesting but I am wondering why the transmission chosen is the type which puts the engine low...rather than the Aussie RC Rotortech transmission which allows placement of the powerplant up much higher, closer to the rotor, which would seem to allow more manuver agility...I think. One respondant mentioned "pendulum effect" from having more weight hung lower under the disc; it would seem that a more "linear" powerplant installation up high would be less pendulous.
Not to detract from the transmission or installation Bergen has gone with, of course!
Thanks again to all for the good info.

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04-04-2005 04:28 PM  13 years agoPost 14
Donovan Dow

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Barrhaven Ottawa Ontario Canada

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Morning All

It has been my experience when the CG is near the rotor head the rolls are fantastic but the loops were dogs (not so good).

cheers
Don Dow

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04-04-2005 07:50 PM  13 years agoPost 15
wolfdad

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Southern Maryland

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Gregory,
I think that was said with a lisp as well....as I review my latest edition of "Bait" magazine.

wolfdad sends....and grins....

"There are those who have...and, those who will" IRCHA #2117, AMA #70068, Turbine Waiver #105

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04-05-2005 09:48 AM  13 years agoPost 16
coolice

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Northamptonshire, England

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Hey,

I'd just like to chime in here & say with a resounding yes that 3D can be done with a turbine heli.

With the WREN Century Predator over here in the UK I am performing mild 3D and pushing harder & harder the more I fly it.
In my mind the machine I have is more capable than I am if I'm honest, plus I do also have a fondness for it and so play cautiously until asked to try something. But the time I put on the stick with it the better I get at exploiting the power & agility it has.

Although I do feel that 3D'ing a turbine require's more of a softer touch to the sticks rather than the proverbial stick bashing. As my main area of concentration is on FAI F3C this type of flying suits me better. My 90's I can flip & roll pretty quick, but a weighty turbine needs respect.

I've just recently fitted a GY401 to the machine which now inspires a lot more confidence as I do not have to worry about the tail so much. The previous 460T I had didn't hold at all and consequently held me back from enjoying it as much as I do now.
.

Ian Contessa
Team Robbe SchluterUK
Midland Helicopters

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