Bell HTR
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Interesting... but comparing to X2... huge. And will pose some challenges with stability. The idea seems to be coming back - first with Focke-Wulf FW61, then Fa223, and than Ka-22 and Mi-12, not very practical then, but today a FBW should eliminate some problems.
Although the size...
Well, future looks interesting. With the Piasecki, Sikorsky and Bell concepts, wonder what's Boeing up to
Although the size...
Well, future looks interesting. With the Piasecki, Sikorsky and Bell concepts, wonder what's Boeing up to
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On "The DEW Line" blog that poster is in full detail
I don't have much against that concept (except the rather large footprint) although I'm curious what Nick have to say about it, as - paraphrasing his words - this one have all the parts of a Chinook and F-8 Crusader.
I wonder if someone working on that concept thought about giving those wings enough lift to let it glide at least into survivable crash in case of one, or both rotor gearboxes seizures/catastrophic failures, as this design would provide such possibility.
I don't have much against that concept (except the rather large footprint) although I'm curious what Nick have to say about it, as - paraphrasing his words - this one have all the parts of a Chinook and F-8 Crusader.
I wonder if someone working on that concept thought about giving those wings enough lift to let it glide at least into survivable crash in case of one, or both rotor gearboxes seizures/catastrophic failures, as this design would provide such possibility.
Why not consider this flying prototype funded by the US Army.....it shows much merit....and looks more sensible than with the HTR or V-22.
CarterCopter Technology Demonstrator on CarterAviationTechnologies.com
At 7:40 AM on June 17, 2005, while flight-testing for a U.S. Army contract out of Olney Airport in Texas, the CarterCopter reached μ-1 (Mu-1). This is the first time in history that any rotorcraft has reached μ-1. The condition was achieved during normal flight-testing while collecting data on a newly developed speed controller for the rotor. The milestone attempt was not planned but evolved as flight-testing proved the rotor to be very stable as the rpm was decreased. Test pilot, Larry Neal, was decreasing rotor rpm in small increments when he neared μ-1. With all systems stable the decision was made to proceed to μ-1. Data from the flight shows that the airspeed was 170 mph and the rotor was slowed to 107 rpm giving a μ value of 1. Previously, the lowest rotor speed achieved was 115 rpm. The μ-1 flight time was just 1.5 seconds before Neal reduced the throttle to slow the aircraft, but the aircraft was operated continuously above μ 0.9 for over 20 seconds, and the high μ flight was accomplished without incident. The pilots commented that the aircraft was so smooth that there was no vibration or noise to indicate that they were in a rotary wing aircraft, let alone one flying at 170 mph with the rotor slowed to 107 rpm.
Oh wow a compound tiltwing, what a novel concept.
This goes hand in hand with the Xworks' X-Hawk......
But the most important question is.............Is Bell completely out of the 609?
This goes hand in hand with the Xworks' X-Hawk......
But the most important question is.............Is Bell completely out of the 609?
Last edited by tottigol; 12th May 2009 at 04:42.
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It's all good and nice but...
While Bell is pondering about the military sector the civil sector again is left on its own devices. For f%$k sakes develop a civil work horse without those damn huge tail fins which tolerates a bit more crosswind without "binging" away on certain parameters.
Seems the the Ted Stinson philosophy is still prevailing at Bell. "I don't care about the civilian sector - I only care about the military projects".
Seems the the Ted Stinson philosophy is still prevailing at Bell. "I don't care about the civilian sector - I only care about the military projects".
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The link in post #1 says that the Hybrid Tandem Rotor could achieve a forward speed of 225 kts, but the video appears to show turbo-jets.
Strange. The cruise speed and the turbo-jets are not compatible.
Lt.Fubar;
It had to happen, eventually. Bilateral Symmetry
Dave
Strange. The cruise speed and the turbo-jets are not compatible.
Lt.Fubar;
The idea seems to be coming back - first with Focke-Wulf FW61, then Fa223, and than Ka-22 and Mi-12, not very practical then, but today a FBW should eliminate some problems.
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HTR pros and cons:
I'm strictly a mechanical systems guy with very limited knowledge of rotorcraft aero or dynamic issues, but here's my two cents:
In short, the HTR seems to be Bell's attempt to circumvent Sikorsky's X2 concept. Although it's hard to tell from the images, it appears as though the HTR's rotors might actually intermesh slightly. A large diameter rotor that doesn't fully tilt (like the V22) would seem to help make the HTR more efficient than a conventional tilt-rotor, without the need for a multi-speed transmission like the X2. Even though it would have a lower forward speed, apparently Bell thinks it is a better compromise overall?
In short, the HTR seems to be Bell's attempt to circumvent Sikorsky's X2 concept. Although it's hard to tell from the images, it appears as though the HTR's rotors might actually intermesh slightly. A large diameter rotor that doesn't fully tilt (like the V22) would seem to help make the HTR more efficient than a conventional tilt-rotor, without the need for a multi-speed transmission like the X2. Even though it would have a lower forward speed, apparently Bell thinks it is a better compromise overall?
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Originally Posted by Dave Jackson
The link in post #1 says that the Hybrid Tandem Rotor could achieve a forward speed of 225 kts, but the video appears to show turbo-jets.
Originally Posted by riff raff
Even though it would have a lower forward speed, apparently Bell thinks it is a better compromise overall?
I love to see those design concepts, especially the LHX program was a golden age of weird drawings. The problem here I see also is with promoting the design to military first. I'm not sure this is a good idea, there is a rare opportunity today, with recent crashes - to promote development of a design that could bring people down safely in case of catastrophic gearbox failure in offshore environment. HTR can have this potential, and not exploiting this opportunity seems weird
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The June issue of Rotor & Wing says the Bell Hybrid Tandem Rotor design is: "led by industry veteran Nick Lappos."
Why is it called "tandem rotor"?
Looks like a side by side configuration, I must be missing something.
slowrotor
Why is it called "tandem rotor"?
Looks like a side by side configuration, I must be missing something.
slowrotor
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Dave
you have got to be having a serious lend of everyone with that "concept" drawing, or "concept" photoshop.
it looks to me as if I can spot at least five different aircraft types there from the first ME 262 through to the F 105, sorry, also the glass of the A6.
fair dinkum, it was a good laugh.
but, i can say that anyone who has tried to fly a rotorcraft even with 2 degrees more lead than they are supposed to have and think for one milli-second that lead as portrayed in your "concept" will not destroy the rotor system as soon as pitch is pulled is pulling more than fantasy could ever allow, even in Dr Who.
Of course that is providing that the rotor systems were set up "on the floor" to be exactly neutral at flat pitch, otherwise there would have been broken glass everywhere.
cheers tet
you have got to be having a serious lend of everyone with that "concept" drawing, or "concept" photoshop.
it looks to me as if I can spot at least five different aircraft types there from the first ME 262 through to the F 105, sorry, also the glass of the A6.
fair dinkum, it was a good laugh.
but, i can say that anyone who has tried to fly a rotorcraft even with 2 degrees more lead than they are supposed to have and think for one milli-second that lead as portrayed in your "concept" will not destroy the rotor system as soon as pitch is pulled is pulling more than fantasy could ever allow, even in Dr Who.
Of course that is providing that the rotor systems were set up "on the floor" to be exactly neutral at flat pitch, otherwise there would have been broken glass everywhere.
cheers tet
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topendtorque
Never, never 
No joke. It was serious. ~ seriously
It it was a Blokow concept similar to the Bolkow P-310 concept. Both of which had Interleaving configurations.
The large 40-degree lead-lag decreases the airspeed differential between the leading and trailing blades during high speed flight.
They were based on the Bolkow Bo-46
Boelkow Bo-46 helicopter - development history, photos, technical data
Bölkow Bo 46 - Wikipedia, the free encyclopedia
Worldwide Rotorcraft Website: Unusual Rotorcraft - Bolkow 46 Pics
Dave
you have got to be having a serious lend of everyone with that "concept" drawing, or "concept" photoshop.
No joke. It was serious. ~ seriously
It it was a Blokow concept similar to the Bolkow P-310 concept. Both of which had Interleaving configurations.
The large 40-degree lead-lag decreases the airspeed differential between the leading and trailing blades during high speed flight.
They were based on the Bolkow Bo-46
Boelkow Bo-46 helicopter - development history, photos, technical data
Bölkow Bo 46 - Wikipedia, the free encyclopedia
Worldwide Rotorcraft Website: Unusual Rotorcraft - Bolkow 46 Pics
Dave
