Another half-baked VTOL idea - two F-35 prop. units for VTOL transport

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doggtag RE:Another half-baked VTOL idea - two F-35 prop. units for VTOL transport 2/19/2005 4:31:24 PM

Interesting idea. It was similarly tried decades ago, with the (West) German Dornier D031, utilizing two (Harrier) Pegasus engines, and optional wingtip lift pods. The problem here is, you'd need absolute reliability in your engines to guarantee continuously safe VTOL ability: otherwise, if one engine goes down, you've just become a standard long runway (or at most STOL) transport. link There is also a considerable amount of interesting designs, both built and concepts, available at link (of course, I'm partial to the vastly-improved, albeit it sci-fi concept, V-22-derived VTOL used in Ghost in the Shell, Stand Alone Complex.) .

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reefdiver RE:Another half-baked VTOL idea - two F-35 prop. units for VTOL transport 2/19/2005 7:29:52 PM

Problem with engine reliability and/or combat engine damage is same as for the V-22, except the V-22 can't land with props down.. Also, the Dornier mentioned was created in 1967...the JSF power plant and ducted fans have got to be better

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blacksmith RE:Another half-baked VTOL idea - two F-35 prop. units for VTOL transport 2/20/2005 11:41:46 PM

Like the V-22, the F-35B is a mechanical nightmere. Show me what part of that aircraft doesn't move in order to hover. Putting two of those things together would create... Lord I have trouble envisioning it. Now I have to go wash my mind's eye with Drayno.

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perfectgeneral RE:Another half-baked VTOL idea - two F-35 prop. units for VTOL transport 5/8/2005 10:10:17 PM

The liftFan gives you cool thrust that you can duct around. You could have two F136 at the back either side of the tail. Rear loading would be out of the question, but 75,000lbs of thrust can really lift. Due to ineffeciencies the resultant downward thrust would be a lot less, but still high.

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blacksmith RE:Another half-baked VTOL idea - two F-35 prop. units for VTOL transport 5/12/2005 7:42:47 PM

The reason the X-35 won the JSF flyoff is that the fan provides more thrust than just ducted thrust from the engine. It effectively increases the by-pass ratio of the engine. The problem is the complexity. I predict the F-35B to be a widow[er]maker. (have to be PC you know) When anything in the drive train hiccups while hovering, the aircraft will pitchpole end over end. This gives the pilot about a 50% chance of ejecting straight into the ground. At least the Harrier tended to settle level if the engine died. Two F-35B STOVL propulsions systems, with ducting routed all over... Darn, I have to go flush my minds eye with Drayno again.

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PowerPointRanger Mounting the engines in-board 9/17/2005 1:03:27 PM

One of the unique features of of the F/A-35 VTOL variation is that it does not rely entirely on engine thrust for its vertical lift. It uses the engine to power a vertical fan in the front of the aircraft via a transmission. The advantage of this is that it avoids the problem of heated jet thrust getting sucked into the intake. This can cause the aircraft to lose vertical thrust because the air can no longer expand from being heated (the expasion of air is source of the thrust) since it is already heated/expanded. I could see this type of system being used for a transport version of the F/A-35. The fans could be embedded in the nose and/or wings, while leaving the engines inboard. There's no question that air transport is in something of a crisis. The choppers are becoming old/obsolete & the Osprey is looking like an expensive boondoggle that will be obsolete from the moment it enters service. We need a plan B.

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PowerPointRanger Another point 9/17/2005 1:08:06 PM

Another advantage of the transmission-fan combo is that it can operate even with 1 engine down. I know the F/A-35 only has 1 engine, but if our hypothetical transport had 2, one engine could power both fans (although with only half the power, this might be enough if there's a light load).

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