Turboprop Skyraider?

[GregP]

In another thread we came up with an idea for a modern turboprop Douglas AD-1 Skyraider. The real turboprop Skyraider, the Douglas A2D Skyshark, was a failure … mostly due to the fact that Douglas tried to use a 5,100 HP Allison XT-40 turboprop (no real problem) driving a contra-prop gearbox (the fatal fault). Apparently it could chug its way up to 500 mph and climb 7,290 feet per minute … but could not keep the gearbox in one piece.

We came up with the idea to use a single prop version with about 5,000 – 6,000 HP (similar to the Skyshark), but also having a modern yaw damper and electronic stability system similar to the Pilatus PC-21 trainer. In the PC-21, you can exercise the throttle with your feet flat on the floor because the electronic stability system compensates for torque reaction automatically in both yaw and roll.

So the proposal is for a Skyraider with a modern turboprop system … basically a functional Skyshark with modern avionics, modern systems, and a modern gun … possibly one, two, or more chain guns slaved to the pilot’s helmet, but still with some fixed forward-firing armament in traditional configuration. The chain guns would allow off-axis attack, the fixed guns would allow conventional attack, and the power would certainly haul some ordnance. The turboprop would allow MUCH greater acceleration than a jet and would be about as fast as an A-10, clean. Slower, of course, with an ordnance load.

I’d want the ability to launch missiles of various types, small drones, smart bombs, and old-style iron bombs (with accuracy), and perhaps the ability to emply the entire aircraft remotely if required … but I prefer a pilot.

Similar to the F-22, each turbo-Skyraider would know what armament other turbo-Skyraiders had and could employ either their own or someone else’s who was in a better position. This assumes the computer woluld not add undue weight. Otherwise, ditch it and keep the plane agile and formibale. We still want a 7,000 feet per minute or better climb, clean and light.

Opinions?

[MikeGazdik]

Great ideas, that I agree with. Last year I did some digging and the Air Force was looking into procuring some sort of aircraft that you have described. There are a couple of flying specimens. I cannot recall right now.

It is a needed aircraft. Just look at how many times the A-10 was written off as un-needed or un-wanted. It still exists and the mission it conducts is still needed. The A-10 is a cold war weapon though, overly large because it had to defeat Soviet armor. What we are talking about is not an anti-armor weapon. Traditional CAS, with SMART abilities.

[pinsog]

It would still have anti-armor capability, just not with a gun. How many Hellfire missiles could you hang under a 5,000 hp Skyraider?

[GregP]

Exactly, a classic attack plane with modern systems and power, not a dedicated anti-armor aircraft. The chain guns (or similar trainable weapon) would offer a great attack capability during an otherwise off-axis attack path, and the computers would render the torque issue moot most of the time unless they were authored by Microsoft in which case you'd have to upgrade during an attack, unless it feezes. Keep the software in assembly language!

[pinsog]

This aircraft should be about perfect for the war in Afghanistan. Slow enough for good ground support, but higher ceiling than the helicopter gunships. Should effectively bridge the gap between helicopters and jets, especially in the high altitude thin air of Afghanistan where helicopters struggle.

[GregP]

A Hellfire weighs about 100 pounds, so assuming multi-TERs (tripple ejection racks, one behind the other) and maybe 7 to 9 hard points, you could carry 42 to 54 Hellfires if you didn't also have to carry extra fuel tanks (short attack mission). If you DID have to carry ... say ... two big fuel tanks, you'd STILL have 30 to 42 Hellfires if that was the only load out.

I'd say the aircraft would be VERY formidable. Then again, it might need an ECM pod in place on one hard point .... decreasing your load out by six.

[pinsog]

What fixed armament would you give it? What caliber flexible chain gun would you install? Where would you install a flexible chain gun?

[michaelmaltby]

Any Skyraider is a great Skyraider, IMO.

From "tossing" nucs (in practice) in the early years of the CW to chain guns over Af'stan -- what a plane. It's range (in piston engine incarnation) only limited by how much engine oil it could carry ...

MM

[jim]

Mr GreqP
A very good idea ! By coincidence we had the same conversation with a few friends in another forum a few weeks ago.
The lighter turboprop would realese some weight for additional armor as well
. A much more capable aircraft than Super Tucano

[wuzak]

We came up with the idea to use a single prop version with about 5,000 – 6,000 HP (similar to the Skyshark), but also having a modern yaw damper and electronic stability system similar to the Pilatus PC-21 trainer. In the PC-21, you can exercise the throttle with your feet flat on the floor because the electronic stability system compensates for torque reaction automatically in both yaw and roll.

Since you are talking about 3-4 times the amount of power of a Pilatus, are we sure that the electronic stability system would be enough? Or would it just mean a larger rudder and ailerons?

I don't think there would be as much of a problem with gearboxes today as they had back then, so a contra-prop shoudl be well and truly possible. You could also pair a couple of smaller turbines to drive co-axial counter rotating props.

[wuzak]

I wonder if you wouldn't go for a prop-fan.

Like http://upload.wikimedia.org/wikipedi...v_An-70%29.jpg

Progress D-27 - Wikipedia, the free encyclopedia

Europrop TP400 - Wikipedia, the free encyclopedia


I also wonder if the requirements put forth here, like the need for a chain gun (trainable or otherwise) would point towards the need for a pusher arrangement?
http://upload.wikimedia.org/wikipedi...x-TP400-D6.JPG

[davebender]

The Skyraider was a fantastic attack aircraft when it entered service during the late 1940s but that was 65 years ago. The turboprop Skyraider should have entered service during the 1950s.

If we are building a turboprop CAS aircraft today we should start with a clean sheet of paper to take advantage of modern technology.

[KiwiBiggles]

The pusher is a great idea. It would free up the nosecone for decent radar/FLIR etc, and modern ejection seats remove one of the main drawbacks faced by pushers 70 years ago (minced pilot). Perhaps even a canard layout, to keep the engine weight near the centre of lift.

Just checked the specs of the Progress D-27 compared to the R-3350 in the Skyraider. R-3350 1200 kg; D-27 1600 kg - only 400 kg more! Imagine having 14,000 hp to play with!

[GregP]

I'd stick with single turbine-single prop. Before I'd use a gearbox for contra-props, I'd go for twin turbines and coaxial props. That would add complexity, weight, and cost ... so the first choice would be a single turbine.

I'd put either two Vulcans (or similar) gattling guns fixed or four 20 mmm cannons fixed, and either one or two chain guns slaved to the pilot's helmet. If one, the mount would be centerline in front of whatever centerline pylon is mounted ... could even be in the front OF the centerline pylon. If two, the mount would be inside the wing with the chain guns protruding out underneath the wing in relatively streamlined installations. I'd allow for as much as 90° of travel off-axis. Alternately, they COULD be mounted at the wing leading edge, allowing for training the chain guns UPWARD as well as downward. In certain circumstances, it could work to a huge advantage. and the firing arcs could be electronicallty connected to the propeller arc to prevent shooting off your own prop or even the pilot.

With 5,000 to 6,500 HP, the weight-hauling ability should be pretty decent and I'd expect (really) about 400 mph or better in clean condition and 350+ mph loaded, with about a 6,000 to 7.500 feet per minute climb rate. If the two-engine configuration were selected, one engine could be stopped and the prop feathered to extend loiter.

One feature I'd add would be to put in a lot of ammunition, especially for the chain gun(s), so that the extended loiter would not be wasted by quickly running out of ammunition. That would cut down on ordnance, but would allow for extended ground support in a guerilla warfare environment. A possible alternative would be to come up with a wing-mounted (on a TER or MER) ammunition tray that could be mounted next to the gun to extend the ammunition only when necesasary for the mission. Like the Skyraider, I'd use conventional landing gear, not tricycle gear, and would fit it out for Naval operations if requuired. That means folding wings and arrester hook and catapult-launch capability.

The overall size would be about the same as a Skyraider or slightly larger, depending on weight when the design was developed. Smaller is better as long as it remains maneuverable, tough, and rugged.

I'd mandate a symmetrical airfoil on both the wing and the tail so that wing panels and tail stabilators could be interchanged for battle damage repair. I'd skin it with .050" or thicker 2024-Aluminum for ruggedness and stress it for 8g at mnaximum load out (which would mean 12+g at light weights ... though "light" might be relative).

Speed brakes very similar to the Skyraider would be fitted, too. I'd also want a propeller brake, and the plane could have the engine running with the propeller stopped if the turbine were selected to be an indirectly-coupled unit. That might or might not prove useful in normal circumstances, be WOULD in a quick-turn rearm in a hot combat zone.

Just some thoughts about what would be effective today ina limirted war. In unlimited war it could also be effective or could be irrelvant if the Earth is destroyed by nuclear arms.

The concept can be argued as good or bad, but the product has absolutely shown itelf to be useful in real war. The Skyraider was only retired when the R=3350 engine became difficult to service and keep running with the available spares. If the new plane were modular, worn or damaged sections could simply be replaced at any depot. If we mandated an engine mount taht was, say 15 - 20% bigger than needed, then the engine compartment would allow for growth engines to be fitted as well. That adds a bit of otherwise unnecesary wetted area, but we're only talking 400 - 500 mph anyway, so the ectra area isn't very critical.

All just an idea that will probably never see the light of day other than in here ...

[FLYBOYJ]

Would be great to see an aircraft like this fly today but you won't see it flown by any military branch of the US...

Taildragger.