Robinson R66 (merged threads)
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Air intake
Any idea how enough air gets into the compressors ? i think all other turbine heli's i've seen have air intakes - normally toward the front - and i've always been told if these get blocked it stops! I assume the small vents on the back are possibly the air intake and mean you dont fly forward - just backward?
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MJB, increased clearance will help reduce risk of bladestrike, so may also have been a factor.
120, air intakes are at the root of the tail boom. The RR300 may not have been optimised to make use of the dynamic pressure from forward facing inlets in cruise. Normally this would be accomplished with moveable stators at inlet of an axial compressor, but this unit has a centrifugal. I'm planning to read up a lot more on gas turbine design in the future.
helicopter-redeye, is there another name for "chadwickomiter"? I gather this would be some instrumentatiun to measure flapwise movement of blade?
Actually the vertical stabiliser, and blade just above it in photo, appear to have a network of strain guages over them to determine in flight loads. That most likely means this R44 based powertrain prototype is flying R66 rotors and tail fins. Looking at details like the aerofoil section skid struts, this machine is aimed at a good cruise speed.
120, air intakes are at the root of the tail boom. The RR300 may not have been optimised to make use of the dynamic pressure from forward facing inlets in cruise. Normally this would be accomplished with moveable stators at inlet of an axial compressor, but this unit has a centrifugal. I'm planning to read up a lot more on gas turbine design in the future.
helicopter-redeye, is there another name for "chadwickomiter"? I gather this would be some instrumentatiun to measure flapwise movement of blade?
Actually the vertical stabiliser, and blade just above it in photo, appear to have a network of strain guages over them to determine in flight loads. That most likely means this R44 based powertrain prototype is flying R66 rotors and tail fins. Looking at details like the aerofoil section skid struts, this machine is aimed at a good cruise speed.
Last edited by Graviman; 31st Dec 2007 at 11:14. Reason: Typo.
bystander blast
Will jet blast have a distinctive effect to a bystander (it being so close to ground level) or will it mix with down wash?
Also in a typical testing programme (at this stage) would an enlargement of the cabin have to be based on the length of the cabin in the test ship with only way of increasing capacity by width extension, or can the cabin be lengthened?
Could this testing be applied to a completely new cabin?
Mickjoebill
Also in a typical testing programme (at this stage) would an enlargement of the cabin have to be based on the length of the cabin in the test ship with only way of increasing capacity by width extension, or can the cabin be lengthened?
Could this testing be applied to a completely new cabin?
Mickjoebill
Better red than ...
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helicopter-redeye, is there another name for "chadwickomiter"? I gather this would be some instrumentatiun to measure flapwise movement of blade?
IF this is what the device and wire/ tape is for then I guess the engineers would be looking for any blade tracking deviations in certain manoeuvers.
h-r (CDT)
Jetblast
If this would be the final design of the R-66 (which I seriously doubt) it would not be the first helicopter with its "smoke-stacks" close to the ground. There are quite a few 500's out there, high or low-skid and there seems not to be of any problems as long as you stay away from the area under the tail-cone (which should be avoided in ANY case, as there are more imminent dangers there!!!) The enstrom 480, and Schweizer 330-series helicopters also has the pipes under the tail and haven't heard of anyone yet, with "jetblast" injuries.
This is most likely only the testbed for the engine that they have desided to go for in the new aircraft.
This is most likely only the testbed for the engine that they have desided to go for in the new aircraft.
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IF this is what the device and wire/ tape is for then I guess the engineers would be looking for any blade tracking deviations in certain manoeuvers.
Chuck
Crystal balls
That's the magnetic pickup. It's used for determining rotor azimuth (clock angle), rotor speed and triggering the strobe if used
Some are saying the craft is a test bed for the engine and not necessarily anything to do with final layout for the airframe.
Mickjoebill
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Thanks, helicopter-redeye - this system looks nicely automated:
http://www.e-equipments.com/vibrex2000.htm
Some interesting discussions going on here about instrumentation techniques.
MJB, regarding cabin size increase the CG will have been carefully calculated. This machine will have been designed as a prototype using the R66 powertrain, but adapted to an R44 testbed. You will probably find that that the prototype has been massed up to replicated the likely R66 weight (depending on test requirement). This just allows the design engineers to gain confidence in their components/systems, by accumulating some hours before the proper R66 airframe is tested.
I imagine there was a detailed R66 concept evaluation before even starting the powertrain evaluation prototype design. Most likely RHC have done extensive wind tunnel or CFD work and have a very good idea of drag coefficients and cruising speed. I would have though they opted for 3 in the back as a good packaging compromise. From memory a "tadpole" shape with 2.4:1 length:width offers the lowest fuselage Cd. Once the flight testing has proven out the R66 powertrain, you will likely see a prototype with the intended R66 fuselage.
Doing it in small stages is the sign of a well run test/development program...
http://www.e-equipments.com/vibrex2000.htm
Some interesting discussions going on here about instrumentation techniques.
MJB, regarding cabin size increase the CG will have been carefully calculated. This machine will have been designed as a prototype using the R66 powertrain, but adapted to an R44 testbed. You will probably find that that the prototype has been massed up to replicated the likely R66 weight (depending on test requirement). This just allows the design engineers to gain confidence in their components/systems, by accumulating some hours before the proper R66 airframe is tested.
I imagine there was a detailed R66 concept evaluation before even starting the powertrain evaluation prototype design. Most likely RHC have done extensive wind tunnel or CFD work and have a very good idea of drag coefficients and cruising speed. I would have though they opted for 3 in the back as a good packaging compromise. From memory a "tadpole" shape with 2.4:1 length:width offers the lowest fuselage Cd. Once the flight testing has proven out the R66 powertrain, you will likely see a prototype with the intended R66 fuselage.
Doing it in small stages is the sign of a well run test/development program...
I guess I'll see it in a few weeks in Heli Expo Houston
R66 test flight video
Note sure if this has been linked, I assume it is genuine despite not hearing much turbine music...
R66 test flight.. the first?
http://www.youtube.com/watch?v=3gMM7jl_smw
http://www.youtube.com/watch?v=zO1kx...eature=related
Mickjoebill
R66 test flight.. the first?
http://www.youtube.com/watch?v=3gMM7jl_smw
http://www.youtube.com/watch?v=zO1kx...eature=related
Mickjoebill
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I'm going to sound like a smartarse here - without really meaning to I might add - but......
The only people likely to have good enough access to an R66 to get good, high res pictures are those within Robinson.
Give 'em a try, you never know.
Otherwise, does it have to happen right now?
The only people likely to have good enough access to an R66 to get good, high res pictures are those within Robinson.
Give 'em a try, you never know.
Otherwise, does it have to happen right now?
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My understanding is that Robinson is not releasing R66 photos itself, but is not working too hard to prevent others from taking them. Am happy to be corrected on this.
Elan
Elan
Last edited by Senior Pilot; 9th Jun 2008 at 10:09. Reason: Remove advertising reference