Wide Body Avro Atlantic

[kitnut617]

Now that my STOVL Canberra is all but done, just glueing the bits altogether and paint, my mind is wandering to other things.  I'm thinking of what I will do next and I have two 1/48 Harrier kits which I've used parts from, one I had and another Barry (JHM) had given me.  My first plan was to make a twin Harrier out of them (totally influenced by Radish's project BTW) but 1/48 isn't really the scale I like building in, so that little project will be saved for a pair of 1/72 Harriers (something along the lines of a Prowler/Growler VSTOL).

My thoughts have turned to doing something with the two 1/48 Harriers though, but cross scaling then to 1/72.  I'm thinking that 'what-if' the only practical application of a multi-engined STOVL/STOL was in a twin engined layout, what sort of options do you have and what could be used.  I got to thinking about this while doing the STOVL Canberra, someone mentioned not to forget the wing puffers but to my thinking they wouldn't be very effective (if at all), I'm looking at what they would have to overcome. In the side view, the jet thrust stream is very much like a Harrier where you have what looks like 'one' jet stream (but really one behind the other) and the puffers for the pitch can tilt the jet stream back and forth to correct the pitch, but in the front view you have a totally different scenario.  It has two jet thrust streams set 18 feet apart and the wing tip puffers would have to be extraordinarily powerful to overcome the two jet streams.  I think the answer for roll in the hover would be best accomplished by differential engine control.

I remember watching John Farley in a documentary about the Harrier development, on how they solved a problem about controlling the rate of decent while in the hover, they had found that the normal back and forth movement of the pilot's arm as he moved the throttle was too abrupt, so a little knurled wheel was incorporated into the top of the throttle lever, this calibrated the movement much more precisely, rolling it forward increased power and rolling it backwards, decreasing it.  My thinking is that something like this would have been needed to control the two engines only moving side to side but the two operations had to work in one control.  My solution to that was quite simple though, and most people on computers would have had it right under their mouse hand (might still do for that matter), the answer is the little ball found in the mouse.  It controls two axial shafts for the X & Y co-ordinates of the computer, same would happen on the throttle for the two engines, side to side for the engines, back and forth for the power and anywhere in-between for all of it.

So what's this to do with my new project you might ask, well if only two engines were the only practical layout, what happens if you want to have a bigger STOVL/STOL, like an AW681.  The only option would be to have bigger engines --- so 'what-if' the Pegasus was scaled up into a much bigger engine, what could you use it on.  Once again my thinking is you would need a 'proof-of-concept' project, using an existing airframe which leads to what would I use.  There's a number of options open here, I could go something conservative like using a C-130 or a Transall, or something a bit more ambitious, say like a Nimrod -----

[PR19_Kit]

Robert,

Interesting and formative thinking there. 

I know what you mean about the mouse ball, and I've always taken it further as I've used a trackball since my first ever PC, I find it a lot more intutive than physically moving the mouse from side to side, I just roll the ball around with my fingertips.

I even use a utility called 'Mouse-as-Yoke' to use my trackball as a joystick to 'fly' with Flight Simulator 2004 and it works a treat. I'm sure such a device could work well on a full size aircraft.

As for a type to use your idea on, I fancy the Transall C-160, if only because it's already a twin anyway, but also because it has an ENORMOUS fin that I'm sure will be needed to counteract the size of the two lift jets you plan to use. Having seen the only BS100 engine left, in the FAA Museum at Yeovilton, I should think your engines would be BS200s at least, maybe BS300s! 

Having proved the concept the 'production version' could be a 1/144 scale C-17 with four 1/72 Harriers under the wings....... 

I'm looking forward to seeing how you develop this idea.

[philp]

What about an Osprey?  Replace those two large props.

[kitnut617]

Thanks guys, Kit - the fin is something I'm keeping in mind, it would have to be quite substantial wouldn't it ?  Philp - I was thinking something a bit bigger, the Osprey is closer to the Canberra project although I quite like the idea.

If I used a C-130 or Transall, what swept wing could I use on it ? 

[B777LR]

Thanks guys, Kit - the fin is something I'm keeping in mind, it would have to be quite substantial wouldn't it ?  Philp - I was thinking something a bit bigger, the Osprey is closer to the Canberra project although I quite like the idea.

If I used a C-130 or Transall, what swept wing could I use on it ? 

Nimrod wing?

[PR19_Kit]

You want it SWEPT?  

That takes some thinking about in 1/72. The only thing that comes to mind is a section from a 707, KC-135 or E-3  wing of some sort. Even large 1/144 airliner wings wouldn't really be big enough, except maybe for the A380. A B-52 is a tad narrow in chord, but maybe, just maybe, an XB-35 or -49 would do?

Wouldn't you have to mount it further forward to get the centre of lift in the right place? Remember that the nozzles have to be equally spaced fore and aft of the loaded CG to get the VSTOL to work properly. That's why the HS-681 always looked so snub nosed I reckon.

The loadmasters on your device will DEFINITELY have their work cut out!  

[kitnut617]

A question to anyone who might know the answer, is there a list of High Bypass engines and their diameters.  The 1/48 Pegasus fan measures out to the equivalent to 67" in diameter in 1/72, is there an existing engine that is close to that ?

[kitnut617]

Nimrod wing?

I'm thinking of a STOVL Nimrod tanker, the 1/48 Harrier fuselages happen to fit the 1/72 Nimrod wing much like the 1/72 Harrier fuselages fitted the 1/72 Canberra.

[kitnut617]

You want it SWEPT?  

That takes some thinking about in 1/72. The only thing that comes to mind is a section from a 707, KC-135 or E-3  wing of some sort. Even large 1/144 airliner wings wouldn't really be big enough, except maybe for the A380. A B-52 is a tad narrow in chord, but maybe, just maybe, an XB-35 or -49 would do?

Wouldn't you have to mount it further forward to get the centre of lift in the right place? Remember that the nozzles have to be equally spaced fore and aft of the loaded CG to get the VSTOL to work properly. That's why the HS-681 always looked so snub nosed I reckon.

The loadmasters on your device will DEFINITELY have their work cut out!  

I'd not thought the wing would need to be as big as an C-135's Kit but you may be right, I've thought about 737 wings or Airbus 310, even C-141 wings.  You're right though, the wing root would have to be moved forward some.

[PR19_Kit]

I'd not thought the wing would need to be as big as an C-135's Kit but you may be right, I've thought about 737 wings or Airbus 310, even C-141 wings.  You're right though, the wing root would have to be moved forward some.

I didn't mean all of it actually. By cuttng a suitable section out you could fit the chord to suit your engines and wing root dimesnion, I'd hope so anyway.

The only 1/72 scale 737 I know is the DIABOLICAL ex-Aurora -100, modelled on the prototype, and as rare as hen's teeth these days. Does anyone do a 1/72 A310 or C-141 currently at a sensible price? Transport Wings did do a vacform A310 I think, and of course Nova did the C-141 (I have one in The Loft) but they are a) expensive and b) rare.

[jcf]

GE turbo-fan comparisons:
Commercial
http://www.geae.com/engines/commercial/comparison_turbofan.html

Military
http://www.geae.com/engines/commercial/comparison_turbofan.html

P&W unfortunately isn't as convenient, you'll have to go through each type:
http://www.pw.utc.com/Products/Commercial
The PW2000 seems to be closest at 78.5" diameter.


Rolls-Royce(Same deal as Pratt):
http://www.rolls-royce.com/civil/products/largeaircraft/index.jsp
RB211-535 diameter is 74.1".
An RB-211 based lift 'Pegasus-type' engine is not outside the realm of possibility.

The thing to bear in mind about high-bypass ratio turbo-fans is that you can have very different sized fans
mounted to the same basic core.

Jon

[B777LR]

How about an A-400 or C-160 style airlifter, just 20-30 years before, made in the UK/Canada. Transport fuselage of some kind, possibly a C-130 or C-160, possibly with the nose of a 707/KC-135 to make it more jetty. Perhaps even use a russian transporter, such as the An-12, or if you are thinking smaller, An-24/32. Swept T-tail like the C-17 or A-400M. Propulsion would be the two harrier fuselages fitted as pods under wings, or perhaps embedded into the wing roots. Swept and droopy wings. They could be sourced from following 1/72 kits (all rather easy to come by on the internet):

Heller 707/C-135/KC-135/E-3 (would give you a nose too)
Italeri Tu-22 Blinder (very swept)
Italeri Tu-22M Backfire (For the swing-wing version?)
Italeri XB-35 flying wing (lots of wing to work with in that one)
Italeri B-52
Trumpeter Tu-95
Trumpeter Tu-160 (Swing wing)
And of course the Nimrod.

[kitnut617]

I didn't mean all of it actually. By cuttng a suitable section out you could fit the chord to suit your engines and wing root dimesnion, I'd hope so anyway.

The only 1/72 scale 737 I know is the DIABOLICAL ex-Aurora -100, modelled on the prototype, and as rare as hen's teeth these days. Does anyone do a 1/72 A310 or C-141 currently at a sensible price? Transport Wings did do a vacform A310 I think, and of course Nova did the C-141 (I have one in The Loft) but they are a) expensive and b) rare.

Right, not thinking there Kit (getting too deep into this   )  Aurora (Monogram) -100, got one and it is of the prototype but close to a -100, NASA use one and I've got some decals for it. I have a Welsh Models 1/72 737-200 (they do a number of 737 versions in 1/72) and I've got a vac 737-100 too, a Combat Models kit. I've got a Transport Wings (AiM) A310 too, actually it's a CC-150 Polaris, Combat Models does a vac C-141A/B, got one of those, I've also got about five or six C-135's in various variants, one will be a Boeing C-141 (amazingly, when I overlaid the Lockheed C-141A fuselage over a C-135 one,  I couldn't believe just how close the two fuselages are).  So I've got lots to choose from right  

[kitnut617]

GE turbo-fan comparisons:
Commercial
http://www.geae.com/engines/commercial/comparison_turbofan.html

Military
http://www.geae.com/engines/commercial/comparison_turbofan.html

P&W unfortunately isn't as convenient, you'll have to go through each type:
http://www.pw.utc.com/Products/Commercial
The PW2000 seems to be closest at 78.5" diameter.


Rolls-Royce(Same deal as Pratt):
http://www.rolls-royce.com/civil/products/largeaircraft/index.jsp
RB211-535 diameter is 74.1".
An RB-211 based lift 'Pegasus-type' engine is not outside the realm of possibility.

The thing to bear in mind about high-bypass ratio turbo-fans is that you can have very different sized fans
mounted to the same basic core.

Jon

Thanks for that Jon, that will solve a lot of explaining won't it 

[kitnut617]

How about an A-400 or C-160 style airlifter, just 20-30 years before, made in the UK/Canada. Transport fuselage of some kind, possibly a C-130 or C-160, possibly with the nose of a 707/KC-135 to make it more jetty. Perhaps even use a russian transporter, such as the An-12, or if you are thinking smaller, An-24/32. Swept T-tail like the C-17 or A-400M. Propulsion would be the two harrier fuselages fitted as pods under wings, or perhaps embedded into the wing roots. Swept and droopy wings. They could be sourced from following 1/72 kits (all rather easy to come by on the internet):

Heller 707/C-135/KC-135/E-3 (would give you a nose too)
Italeri Tu-22 Blinder (very swept)
Italeri Tu-22M Backfire (For the swing-wing version?)
Italeri XB-35 flying wing (lots of wing to work with in that one)
Italeri B-52
Trumpeter Tu-95
Trumpeter Tu-160 (Swing wing)
And of course the Nimrod.

Some interesting selections there Thomas, my first thoughts on this was, OK, we have the Harrier, we now have a STOVL bomber/ecm/tanker (thanks to chrisonord)but to complete the mix I was thinking we need a 'tanker' size STOVL tanker, maybe just a STOL though.  The idea of using a C-130 or Transall was to prove the big engines would work in this configuration.