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Subject: C-130 Transport Goes Vertical
Puff    11/24/2003 6:52:42 AM
An idea drawn from the early days of commercial aviation may help the Army solve its chief 21st century logistics problem: getting materiel inside hostile terrain without diverting troops to protect supply lines. Responding to a request from the Defense Advanced Research Projects Agency, Groen Brothers Aviation of Salt Lake City, Utah, has devised a way to turn a standard Lockheed Martin C-130 cargo plane into an aerial delivery truck. The converted aircraft could take off and land like a helicopter, then sprint out of harm's way at 300-mph speeds. Converting a C-130 into what Groen calls a Gyrolifter would require altering the airplane's tail assembly and adding a 5-blade rotor. http://rotter.net/forum/scoop/5260.shtml BTW, the american army already tried to do it using rockets and built 2 prototypes. At the bottom of the page (link) there are two photos of it.
 
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WinsettZ    RE:C-130 Transport Goes Vertical   11/24/2003 7:50:38 AM
Hope it doesn't crash like the Osprey. In any case, I think the problem lies in that we may need a new "tactical airlifter": C130 seems suited for Vietnam era stuff like M113 and Sheridan. Today's junk is heavy and laden with electronics and other heavy components (see Stryker). We probably need more airlift in tonnage out of the C130s, and greater range, more then we might need VTOL.
 
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Puff    RE:C-130 Transport Goes Vertical   11/24/2003 9:39:46 AM
you 100% right it's heavy. very heavy. and i find it hard to believe they will build an operational plane with a plopeller. it might fly in dreams, not in reality. vectorial drive like in the harrier is the right thing to use
 
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Heorot    RE:C-130 Transport Goes Vertical   11/25/2003 7:51:50 AM
The aircaft the this is based on was the Fairey Rotodyne developed in the 50's. It used exactly the same idea; uncoupled rotors with rotor tip jets to spin up the rotors. Unfortunately, there was no industry or government support so the project was cancelled. I think that ths would be a better route than Osprey but its too late now. With modern materials and engines I think that this would still work but I agree that modifying a C-130 is the wrong way to go.
 
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Thomas    RE:C-130 Transport Goes Vertical   11/25/2003 8:03:33 AM
I'm sorry but it reminds me of some of the drawing i made at school, when the teacher was more than usually boring. Fine planes; but forgot the engine. As far as I can see, it is a an autogyro, which is STOVL, not VTOL. Providing the frame can take the changed stresses, we will still have to contend with all the maneouvre and handling problems an autogyro has. they tried some years back to give tactical transport vectored thust with the YC-14/YC-15 programme apparently it didn't work - I heard the noise was simply unacceptable - that's a lot if you know what the earplugs they hand out to C-130 PAX are made for. The problem is that some people just won't accept that heavy troops trade operational mobility for tactical mobility - and light troop are vice-versa.
 
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Dancing Johnny    RE:C-130 Transport Goes Vertical   11/25/2003 6:33:48 PM
If memory serves me right, this prototype was developed after the failed Iranian hostage rescue attempt. It was to be used mostly by Special Forces for rescue work. Unfortunatly the rockets on the prototype generated too much heat (reflected off ground and onto wing), and the wing was burned off during one of the test. The project was cancelled after that. I remember seeing photos or video of this failed test about 20 years ago. Does anyone know if there is more info on this?
 
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Heorot    RE:C-130 Transport Goes Vertical - Thomas   11/26/2003 9:40:36 AM
The proposal (and the Fairey Autodyne it is based on) were helicopter on takeoff with the tip jets providing the propulsion for the rotors and thus no tail rotor was required. Once airborne and moving forward the tip rotors were switched off and the aircraft did fly as an autogyro.
 
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wagner95696    RE:C-130 Transport Goes Vertical   12/29/2003 1:09:25 AM
I think this 'Roto-Herk' concept is a good idea, much better than the Osprey. It is always better to build a new design from scratch but, I believe, the idea behind Groen's concept is that converting an existing aircraft would provide a quick and cheap way of testing the concept. Besides there are a lot of c-130 airframes spread around the world. Compared to the Osprey it avoids the complexity of rotating engines and rotors. There are no clearance problems beteen any of the rotors/props and the ground. Because the nain rotor is centrally located there is not a problem of assymetric thrust and resultant control problems if an engine fails. Compared to a vectored thrust aircraft the has minimal impact on the aircraft's useful internal volume, no ducting, no center of gravity problems. An autogyro also has good autorotation characteristics which could help a damaged aircraft make it down safely. Combining the autogyro with a large, fast, long range aircraft such as the C-130 could make a good search and rescue platform. Combined with Lockheed's proposed c-130 seaplane version it would be unbeatable. VTOL is much overated. It uses too much fuel and severely limits payload. In a transport payload and range are everything. Speed is quite secondary. An STOL autogyro does not need to generate enough power at the main rotor to physically lift the aircraft vertically into the air, as does a helicopter. It is only necessary to produce enough rotor rpm to produce a significant amaount of lift. Some autogyros use mechanical rotor drives with clutches to spin up the rotor but that adds weight and mechanical complications. It would not be surprising that with all the progress that has been made with very light, very compact electric motors in recent years that it would be possible to use an electric motor drawing power from the main engines to spin the rotor. Furthermore, autogyros do not have an inherent problem with maneuverability. Just as helicopters require different techniques than fixed wings Gyros require different techniques than either. Not better. Not worse. Just different.
 
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Heorot    RE:C-130 Transport Goes Vertical - Wagner   12/29/2003 7:42:36 AM
If you look at this site: http://www.helis.com/50s/h_rotdyn.php you will see that the rotor tip jets on the Autodyne were powered by air bled off from the main turbine engines, so there was little in the way of weight penalty with this system. Given that a production version was proposed that could take off and land vertically whilst carrying between 57 and 75 passengers, and all this using 1950?s technology, it makes Osprey look a little sick. The comparison below is for the flying prototype. Look at the weight/capacity/power in particular. The stats for the flying prototype were: Cruise Speed: 300 km/h Range: 700 km Weight: Max: 14.900 Kgs Crew: 3 + 40 Powerplant: 2 x 2.800 hp Napier Eland NEL7 Rotor Span: 90ft For comparison: Osprey Weight: 47,500 lbs Cruise speed: 272 knots Crew: 2 + 24 Powerplant: 2 x Rolls-Royce/Allison Turboshaft Engines, 6,150 shp Each. Wing Span: 41ft 1.75in Span with rotors: 83ft 10in
 
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wagner95696    RE:C-130 Transport Goes Vertical - Wagner   1/4/2004 8:32:09 PM
I agree the Rotodyne was, and is, a great concept far superior to OSPREY. I believe that one reason for Rotodyne's cancellation is that it was conceived for deployment from downtown 'heliports' and the tip rotors were VERY noisy. I think they utilized tip burning whereby hot gas from the compressor state wwas mixed with fuel in the rotor tips and ignited to produce jet thrust. Several helicopters using 'jet propelled' rotors, including ram jet engines, have been tested but all were eventually rejected because of noise and high fuel consumption. I seem to recall a Hughes helicopter prototype that was proposed as a USMC heavy lift helicopter several years ago but it met the same fate. That is why I proposed an alternative quieter rotor drive.
 
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Heorot    RE:C-130 Transport Goes Vertical - Wagner   1/6/2004 9:17:14 AM
I didn't realise that was the reason. Of course, for the military, noise is irrelevant. In flight the rotors wouldn't be powerered so I don't think that fuel consumption would be a problem now for military applications.
 
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