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Airbus Helicopters offering X3/Racer to US Army
Airbus Helicopters offering proposing X3 / Racer offshoot to the US Army FARA https://www.rotorandwing.com/2019/02...t-competition/ Cheers |
I'll give Airbus top marks for thinking outside the box, and higher marks for being pure fantasy.
American stuff has to be deployable. That is due to US strategic situation and a thing called geography. Now look at the profile of that thing, and tell me how you fit it into a C-5 or a C-17, as compared to an Apache. You've got some significant structural bits spread out that hold the engines/props on. Is that detachable, or not? If not, don't even bother to show up. One MAJOR strike against the US Army buying this particular kit, regardless of how neat of a flying machine that it is, unless those two assemblies that end in the propellers are detachable. |
Originally Posted by Lonewolf_50
(Post 10396939)
Now look at the profile of that thing, and tell me how you fit it into a C-5 or a C-17, as compared to an Apache.
You've got some significant structural bits spread out that hold the engines/props on. Is that detachable, or not? If not, don't even bother to show up. Your remark is interesting, but the Bell V-280 does not seem to have a foldable system for its large wings and rotors either (unlike the V22) ... |
Originally Posted by Lonewolf_50
(Post 10396939)
I'll give Airbus top marks for thinking outside the box, and higher marks for being pure fantasy.
American stuff has to be deployable. That is due to US strategic situation and a thing called geography. Now look at the profile of that thing, and tell me how you fit it into a C-5 or a C-17, as compared to an Apache. You've got some significant structural bits spread out that hold the engines/props on. Is that detachable, or not? If not, don't even bother to show up. One MAJOR strike against the US Army buying this particular kit, regardless of how neat of a flying machine that it is, unless those two assemblies that end in the propellers are detachable. “You’re on the right track,” Tumpak said, when asked if the Airbus offering is based on X3 technology. Tumpak spoke to reporters Feb. 19 during a visit to the Airbus plant in Donauworth, Germany |
The USA FARA RFP does not limit aircraft dimensions or stipulate deployment criteria, probably on purpose to avoid disqualifying particular designs. The UTTAS specifications stated that 2 aircraft were required to fit inside an USAF C-130. However, how often has that been done? To this day the H-60 design lives with the consequences. Self-deployment is always an option.
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where there is a will there is a way.
They ship Chinooks by plane. How do they deploy a CH53 to the dust bowl? Super Pumas don't flog across the ocean on their own do they?? What about Russia, how do they get MI 26's great distances? Thinking outside of the box is a requirement here. I'm sure if Airbus knows this has to fit in a plane they will design it to do so. They aren't new to this game at all. |
Super Pumas don't flog across the ocean on their own do they??
Originally Posted by GrayHorizonsHeli
(Post 10397576)
What about Russia, how do they get MI 26's great distances?
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JimEli,
The C-130/C-141 carriage requirement for UTTAS nearly killed the UH-60 due to the low rotor head causing extensive vibration and drag issues (not to mention concerns over disc/cockpit interaction…) - only solved by the clever introduction of a removable rotor mast extender. It would be interesting to know how often the -60 has been shipped by -130…. |
Originally Posted by Tatischeff
(Post 10397462)
Your remark is interesting, but the Bell V-280 does not seem to have a foldable system for its large wings and rotors either (unlike the V22) ... |
Originally Posted by Evalu8ter
(Post 10398223)
JimEli,
The C-130/C-141 carriage requirement for UTTAS nearly killed the UH-60 due to the low rotor head causing extensive vibration and drag issues (not to mention concerns over disc/cockpit interaction…) - only solved by the clever introduction of a removable rotor mast extender. It would be interesting to know how often the -60 has been shipped by -130…. https://cimg1.ibsrv.net/gimg/pprune....efd2575e00.jpg I’m aware of one transport via C-130, an incredibly tight fit. Since the C-130 could access smaller airfields, it was therefore thought beneficial. IMHO, a highly impractical form of transport, which in real life situations were avoided through alternative deployment options. |
Originally Posted by Nubian
(Post 10397666)
Yes, they do, lots of ferry flights from France to China etc.
They fly them..... fill the cargo compartment with great big ferry-tanks.... or you have to fly the damn thing chopped up as spare parts! then its not impossible to do that with Airbus' offering now is it? Thats all I am saying. where there is a will there is a way. The Generals and who ever else makes the plans just need to think more to get it done |
The decision to raise the main rotor had nothing to do with vibrations. It had everything to do wit a 20-25 kt deficiency at the high speed level flight end of things, compared with predicted performance. An aero performance expert performed a detailed analysis which indicated the culprit was the upflow of air over the relatively flat sloped cockpit front, which was stalling the entire inner front part of the rotor disc. He produced some dramatically impressive, wall sized computer visual flow mosaics “ proving “ his theory. Big meeting and a decision to raise the rotor to gain back the predicted speed. A monumental effort, including a full scale fatigue test to the modified main shaft, resulted in flying the extended shaft 30 days after the meeting. The first flight test ( done at design GW ) forward flight Vh ( max speed at 100%Q-2800 SHP then ) revealed an increase of exactly zero knots. BUT, the 5P vibes ( not a typo ) were reduced dramatically and the raised rotor also eliminated an “ elephant in the room “ issue with regard to main blade to cockpit/engine nacelle/tail cone clearance* in operational/maneuvering flight conditions and victory was declared. Said engineer departed the company some months later. *there is a picture in the SA archives showing the cockpit view from behind with yours truly and Dick Wright, then Chief Pilot. On the top of the instrument panel is a horizontally oriented instrumentation box showing real time blade clearance over the cockpit, engine nacelles and tail cone. There were four modified Chicago Aerial electronic blade tracker sensors feeding blade clearance data to that box and thru the telemetry system to the flight test engineers. I’ll add one early data point: just doing low speed flight in the Stratford flight field, and slowing down normally back to a hover from a paced forward flight at 35 kts, the clearance to the cockpit roof structure was down to 5 inches. There is a great story about how that box got there, but you won’t find it in the book. |
Originally Posted by JimEli
The short nose and canted tail rotor are the primary vestiges of the transport requirement.
The lift was not totally free as it mucked up some of the handling qualities. But, that made for some interesting work for him as he was a flight controls guy. |
Originally Posted by IFMU
(Post 10398376)
The UH60 was a helicopter out of my Father's generation.
... “The Sikorsky UTTAS was designed with its 4-blade tail rotor canted upwards 20 degrees to provide approximately 400 pounds of extra lift. This lift at the tail permitted the aircraft center of gravity to be placed aft of the main rotor, which allowed the nose and cockpit to be moved aft thereby shortening the fuselage length to better fit inside the C-130 cabin during air transport.” |
Originally Posted by JohnDixson
(Post 10398350)
The decision to raise the main rotor had nothing to do with vibrations. ... *there is a picture in the SA archives showing the cockpit view from behind with yours truly and Dick Wright, then Chief Pilot. On the top of the instrument panel is a horizontally oriented instrumentation box showing real time blade clearance over the cockpit, engine nacelles and tail cone. ... In some old A model variants we flew, there was a small tab riveted to the upper windshield support, in front of the engine power control levers. I always thought it an odd gizmo, and could never figure what is was for. Several years ago, I contacted a Sikorsky test pilot, who had to ask around the plant until finding an old engineer who said it was a mounting point for a piece of test equipment. The tab was not removed from the production plans, the result being, the mounting bracket was incorporated into many an early Blackhawk. Possibly the box you refer to? |
JimEli, re post #15; I don’t recall the tab you refer to in front of the throttle quadrant. Can say that it wasn’t part of the blade clearance instrumentation, as that cockpit clearance senso was further aft on the roof so as to be the least clearance point as measured from a straight line from the elastomeric flapping hinge to forward structure. ( I do not recall this detail, but typically in discussions like this, there was additional consideration of the blade bending resultant after contact with the in flight droop stop ). |
[QUOTE[color=left=#000000]Like the V-22 the production V-280 will be self deplorable anywhere in the world and not need an air lift. As for the Sb-1 Defiant it is not self deployable and will not fit in a transport without major disassembly due its height.][/QUOTE]
The production V-280 will be self deplorable?....Freudian slip?....Sorry Sultan, I just couldn't resist. |
IFMU.in post #13, you noted: " The Boeing UTTAS entry was about 400lbs short of the lift spec requirement." Had not heard it expressed that way. From experience during the fly-off, there were two events which indicated that the hover performance wad different by a very significant margin. 1. Ft Rucker Al Shell Field. Training of the Army pilots designated to perform the operational eval at FT Campbell. Same day-same weather. Both the Boeing and SA aircraft had cargo hooks approved for 7000 lbs.The sling load consisted of seven, 1000 lb drums, individually attached by steel cable to a collector ring, which could then be easily slipped into the hook by a ground crewman standing on one of the drums.SA went first and starting with full fuel, trained all their 10 pilots, stopping after 5 to refuel. No issues with the pilots or load. Boeing then started and could not budge the 7 drum load. Disconnected one drum and tried again. No luck with 6000 lbs. Disconnected another drum and just about lifted that 5000 lb load to a low hover, from which they carefully did a very slow takeoff.No HOGE noted. 2. FT Campbell KY. One UTTAS requirement was to sling the new Army vehicle called a Gamma Goat. Weight was 7000 lbs. The Army pilots/crew took a fully equipped SA UTTAS with full fuel picked up the Gamma Goat, flew it around and landed it without an issue. As did the Boeing UTTAS, EXCEPTwe learned later, from an Army pilot flying that day, that the Boeing UTTAS had only 400 lbs of fuel, had removed all the cabin interior and seats and all but a single UHF comm radio. Full fuel on UTTAS was about 2400 lbs as I recall. You can do the math. |
JimEli a further comment re that tab mentioned in Post #15. After being bothered about a dim memory, I sent a note to a very good friend with what seems like a photographic memory, and this is his reply to my query: ” You jumped in an SH-60B with me one day and said "what it that bracket doing here; it was only for flight test instrumentation!" We told Alan Walding, who decided it would cost more to take it out than leave it in. But it had been removed from UH-60! “ So, Jim, your recollection is confirmed. Best, John |
Originally Posted by Evalu8ter
(Post 10398223)
JimEli,
The C-130/C-141 carriage requirement for UTTAS nearly killed the UH-60 due to the low rotor head causing extensive vibration and drag issues (not to mention concerns over disc/cockpit interaction…) - only solved by the clever introduction of a removable rotor mast extender. It would be interesting to know how often the -60 has been shipped by -130…. |
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