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AH-64 Apache Plane Kit

De-helecopterize the Apache for mission flexibility
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The AH-64 Apache is widely considered a successful weapons system. It's pretty tough, very flexible, has a wide range of weapons that can hang off it and it looks all cool and black and scary.

It has downsides, but as far as I can see, these are all because of the inherent problems with helicopters. Range, load capacity, speed, max altitude, annoying noise, turn performance. These are all issues when you have to actively generate lift. Everything feeds into this, if you want to move forward, you have to steal some of your lift The faster you go, the more asymmetric your lift becomes... all these things feed into payload/endurance/speed compromises.

Aeroplanes suffer less, so lets make an Apache-plane conversion kit. First, take off the rotors, this is done routinely for transport. Next, lets fit a lovely big hi-wing with all the lovely slats and flaps. Something like a Twin Otter wing, maybe a smaller version of the C130, whatever you can get off the shelf. Now mount it to where the rotors were, should be a bolt on job. Then, have a couple of engines hanging off it. Turboprops seem natural candidates. The bottom of the engine pods should structurally mount to hard points on the end of the little stub wings on the Apache.

The wing should have space for a: lots of fuel b: storage of the rotor blades. Under the wing should be many many hard points for fuel/weapons. Interfacing with the existing controls, some form of tail plane system, and whether to run one of the Apache's engines as an apu will be worked out by people who are good at that.

There, we now have either a: a horrible compromise, b: a long range ferry/ long range deployment option for those without big transport facilities or c: a sort of hybrid medium attack aircraft.

bs0u0155, Aug 14 2014

Mock Up https://www.dropbox.../Apache%20Plane.png
[bs0u0155, Aug 14 2014]

[link]






       OV-10 Bronco   

       [edit: is an attack airplane that looks like, but isn't, an attack helicopter]
FlyingToaster, Aug 14 2014
  

       Awesome concept.   

       Any chance of using the existing turbines for primary or at least additional forward thrust?
doctorremulac3, Aug 14 2014
  

       //OV-10 Bronco//   

       Great aircraft. Doesn't get you an attack helicopter when you get to the forward operating base.   

       Also, a turboprop aircraft gets you out of AAA range. An Apache is nearly always vulnerable to these because of a low service ceiling with any weight on board. So you could fly around in your Apache Plane, dropping munitions on the AAA positions, then take off the wings, and go in nice and low to clear up the rest.
bs0u0155, Aug 14 2014
  

       So, you're hanging wings and hardpoints and feeding control lines at the top in a 'bolt-on job?'   

       I'm a bit skeptical.   

       True story: The local AFROTC's used to pay yearly visit to my college, bringing with them an AH-64, a Huey, and a Blackhawk that we could climb around. While peaking at the AH-64 I happened to notice that the carbon-fibre blade on the rotor appeared cracked. Poor flyboy had to stay there that weekend babysitting it while they brought a new blade to install.
RayfordSteele, Aug 14 2014
  

       //So, you're hanging wings and hardpoints and feeding control lines at the top in a 'bolt-on job?'//   

       No, controls would all be wireless. If we can control a whole Global Hawk via satellite, we can move a few flaps/spoilers via short range digital radio or optical system. It could be as short as a couple of feet, perhaps have an optical transceiver set up on the inner face of each engine pod, dual redundancy, fast, hard to jam.
bs0u0155, Aug 14 2014
  

       What about a rudder, horizontal stabilizer, vertical stabilizer? You say the control surfaces will be wireless but how will they be powered?   

       I hate to say it but, if you want a plane for close air support that has the range and speed of a plane, with the ability to hover and land vertically, the F35 would be less terrible than an Apache with bolt on wings.
DIYMatt, Aug 14 2014
  

       Well, all the control surfaces will be powered in the usual way: generators on the engines, electrical control and usual hydraulic rams etc. Effectively this will be a cheap high wing turboprop with no mid/forward fuselage, remotely controlled from inside the Apache to which it's bolted. I don't expect the Apache-plane to do any taking off or landing vertically. Although Twin otters can get off the ground in 500ft/ 64KIAS, I'd expect a little military money might get that down a bit.
bs0u0155, Aug 14 2014
  

       If fly-by-wire sounded scary, fly-by-wireless sounds even scarier.   

       All that weight hanging on the wings is the problem.
RayfordSteele, Aug 14 2014
  

       //fly-by-wireless//   

       "The recent spate of accidents involving the new "airwire" system were finally traced to the crew's microwave oven..."
FlyingToaster, Aug 14 2014
  

       All that weight hanging on the wings is the problem?   

       Really? A whole Apache is 1000+ kg lighter than a single Trent 900 engine they hang off commercial jet liner wings. They do OK.   

       Every hi-wing plane is essentially hanging from underneath it's wings. Heck, the Apache hangs from underneath its wings WHILE they're spinning 'round. In addition, I'm attaching the wing structure to the hard points on the end of the stub-wings on the Apache (also, plumbed for fuel) creating tough little box sections in a little semi- biplane arrangement.
bs0u0155, Aug 14 2014
  

       //If fly-by-wire sounded scary, fly-by-wireless sounds even scarier//   

       Fly-by-wire airliners are demonstrably safer in terms of control authority than the conventional systems they replace.   

       I like a laser-optical method of relaying info, its hard to jam, and between send and receive points, there's nothing to shoot.
bs0u0155, Aug 14 2014
  

       But the mounting points for those blades are relatively narrow tubes designed to rotate about the long axis of each blade. Fixed wings, especially those with control surfaces, are rather different in terms of the loads they apply to the aircraft.   

       I'm not saying that the wings couldn't handle the weight. I'm saying that in applying all of that weight to the wings, you've increased the plane's inertias substantially in roll and yaw. It'll be a dog since it isn't designed to be a plane anywhere else and effectively carries more useless weight around. I suspect that so much of the thing would need modified that you'd be ahead simply starting from scratch.
RayfordSteele, Aug 14 2014
  

       " I like a laser-optical method of relaying info, its hard to jam, and between send and receive points, there's nothing to shoot. "   

       That could make flying in inclement weather very interesting.   

       Cue music:   

       "Raindrops keep falling on my plane..."
normzone, Aug 14 2014
  

       well water vapor doesn't absorb between 800-900 nm or 1100 up. So use those, although, if you were clever you'd put the light path inside the structure.
bs0u0155, Aug 14 2014
  

       //Fixed wings, especially those with control surfaces, are rather different in terms of the loads they apply to the aircraft//   

       Think of this as more of a plane using a 5 ton Apache as a cockpit, rather than a chopper with a pair of wings bolted on. The wing can a continuous with the whole rotor head mounting to the main spar.
bs0u0155, Aug 14 2014
  

       Leave the bearing in. It can be locked up by the hydraulics on the Apache. Also it doesn't have to take much roll/pitch/yaw loads if the tail and stub wings are all connected up.
bs0u0155, Aug 14 2014
  

       If you hang the engines off of them, that's load inertia that the rotor doesn't typically see.
RayfordSteele, Aug 14 2014
  

       The wing, engines and pseudo fuselage/tailplane construction are all connected together in a standard aeronautical configuration. The Rotor head, tail rotor section AND stub-wing hard points are all connected up. I think the Rotor head will see much lower forces.
bs0u0155, Aug 14 2014
  

       I think you're ignoring forces. Wing torsionals, dynamic inertial reactions, offset weights of engines hanging forward of the wing spar, etc. Your Apache airframe hardpoints are all in the wrong locations.
RayfordSteele, Aug 14 2014
  

       Made a crude mock up. <link> Apart from the very tip of the Apache vertical stabilizer, it fits entirely inside this cheap old Dash-8. Also realised you could leave the landing gear extended and use that as two more hard points.
bs0u0155, Aug 14 2014
  

       Cool. Now you can put the wing on a pivot and call it either the Apachsprey or the Osprhe.
normzone, Aug 14 2014
  

       I'll agree with some of what I've seen above. No need to add engines. The bird already has plenty of power on tap. Just engineer some gearing into the center and nacelle portions of the wings to get that power out to where it's needed. Yes, I'd design the wing to be its own structure, able to lift the aircraft at the mounting point. It's been done before, and it's plenty do-able now. If you can set it up within a day or so, the helicopter can be its own transport into and out of "hot" areas, carrying its rotors in a protected sheath on its belly while enjoying something of the range/speed of a fixed wing turboprop aircraft, and swapping back into helicopter configuration for the duration of its deployment. By the way, don't forget the tail. You'll want to disconnect the tail rotor and attach the antitorque controls to a real rudder, as well as rigging up an elevator (horizontal stab does move 30deg, just make sure it's set up for forward flight). I suppose it might be easier to do these as stated before, with a local ultra-secure wireless network connected to the controls.
spacer, Dec 30 2014
  
      
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