Wide Body Avro Atlantic

[kitnut617]

I've been thinking about another project, I've always wanted to build an Avro Atlantic and finally have all the bits gathered together to start one.  I'm actually planning on building two, one as it was proposed but with Vulcan B.1 wings, but the other as a wide body variant.  I'm going along the same lines as what Avro did with their Tudor, after the first small diameter fuselage version was put into use, the operators wanted a bigger one.

The info I've managed to gather and contacts I've made with people who were in the drafting office when it was being studied, have suggested that there might have been a Boeing connection, because I saw that various diagrams of the Atlantic had a distinquitive Boeing look to the nose (top two pics).  I had asked if there might have been a possibility that Avro would have used the 707 fuselage and the answer I got was "there had been discussions".

So my idea is to have a wide body fuselage and use the B.2 wing and much more powerful engines and keeping with the Boeing theme, I've decided to use a 767 fuselage.  Mainly because there's a good chance I can get one in 1/72 scale in the near future, but also because it's diameter is closer to what I want to use.  Ideally it would have been around 15 feet in diameter (as a competitor to the Handley Page HP.111) but as the 767 fuselage diameter is 16'-6" I think it would be close enough.

Now the engine scenario I've been giving a lot of thought to.  It's pretty obvious from studying a cutaway drawing of a Vulcan (3rd pic) that the 20,000 lb thrust Olympus was probably the max that could be installed in a Vulcan as it was, the engines performance being dictated by the intake ducting size with this being dictated by the main spar depth.  Anything that required more air would have meant a major center wing re-design I think.  But I don't think it wasn't considered, I saw in BSP-Bombers since 1949 a picture of a Phase 6 Victor, which had massive air intakes so the idea wasn't dismissed.

[kitnut617]

Studying the cutaway, I can see that the engines were set quite a bit further back to the front main spar but the boxes that the engines sit in would prevent an engine getting any bigger diameter wise, it would seem though the length of the engine could be longer.  The main spar is also the front end of the bombay (the rear spar being the back end) and after seeing this cutaway, my idea for a bigger engine for the Atlantic started to fall into place.  I'm going to give it high-bypass engines and I'm thinking of modified Pegasus 11 Mk 106 or 107 engines.  Instead of having the cold air coming out of swivelling nozzles, I'll have the plenum revised to have the air coming out of ducts on top and below the engine, something very similar to how the RB-57F has it's TF-33's configured.  

This will need a new center wing section and as this is for the Atlantic and not the Vulcan, a much deeper main spar can be used and wider engine housing boxes too.  Another thing is I could even use a second main spar right at the fronts of the engine fans because there's no bomb bay to consider, the space between the two spars where it goes under the passenger deck, being one large fuel tank.

I will go with three 4-wheel bogies, two in the normal place and one on the centerline.

[Mossie]

Robert, it'd be less spectacular, but how about a non-reheated version of the Olympus 593?  It produced 30,00lb dry so that would give you some oomph.

Following your thought lines, you could use the RB.431 straight-through Pegasus variant of Pegasus?  That & the Medway, I vaguely recall there was a straight through version of this engine too?

[kitnut617]

I'll have a look at those Simon, but my thoughts are to have the bypass air going over and under the wing in the center section, I was thinking that the exit of the air ducts could be made to work like the CFM engine reversers, where the rear half of the duct moves back and toggles some deflectors so the bypass air turns to brake the aircraft on landing.  Something like that anyway.

[Mossie]

So I'm guessing your intending it as some kind of boundary layer control, blowing air over the wing to improve lift?  Kind of like the YC-14 & An-72, just intergrated into the wing?

[kitnut617]

I wasn't thinking of boundary layer blowing but it could couldn't it ?  If you look at the pic of the RB-57F below you can see that the bypass air was ducted down a channel above the engine nacelle, it also has a channel on the underside too so I don't think this has any boundary layer control to it.  If you notice, the bypass air is prevented from going across the wing by being blocked off up the sides of the nacelles

If a system like that was put in a Vulcan wing the front of the engine is at about half chord, the bypass outlet edge would be about 2/3 to 3/4 back from the leading edge, so wouldn't have a lot of boundary layer control anyway, I'm thinking

[Mossie]

Robert, I've had a look at the Atlantic entry in the Aerofax guide for the Vulcan.  There are some GA drawings of a later Atlantic design than the one you've got above.  The nose & fuselage is a little different with a bit less of the Boeing look about it, but the main point of interest is the intake & accomodation for the eingines.  They've been re-positioned approximately half span, there are fairings to take the engines due the redcued wing thickness in this area.  I assume this was for noise reduction to the cabin & possibly to improve saftey in the event of an engine explosion or fire. 

The bypass ducts sound good, they'll add a bit of interest.  I think your right, with the bypass air exiting in the position your mentioning they probably wouldn't add that much to the wing, but they could blow the flaps for extra take off performance?

[kitnut617]

Simon, if it's this diagram below,  the information I was given was that this is an earlier design using a Comet nose

[PR19_Kit]

Robert,

Looks loads better with that nose! How about combining the two?

[kitnut617]

Well, I've already acquired a 1/72 737 fuselage front for the 12'-6" diameter Atlantic Kit, for the wide body one I've got a line on a 767 fuselage (in 1/72 scale).  I could go with an Airbus nose which is similar to a Boeing but then the fuselage diameter gets too big, the Airbus A310 being the only one I could try to get in 1/72 scale.  I think the diameter is 19 feet or something like that.  I was planning on modifying the noses by making them a bit more pointy though, and change the windshield outline a tad.

[Mossie]

Thats the one Robert.  In the Aerofax guide it states the first pic you've got above as being from June 1953, the one in your recent post dating from September 1953.  Phil & Tony Butler are the authors, I know you're in contact with Tony so it might be worth calarifying it with him?

From the main body text:
[qoute]The Atlantic had four engines, Olympus, Rolls Royce Conway or any other engine of equivalent thrust, placed some way out along the wing (when the intitial data was released in June 1953these sat alongside the fuselage).[/quote]

Accompanying the same pic as the first one from your first post:

This impression of the Type 722 Atlantic was first released to the public in June 1953 and shows theengines next to the fuselage as per the Vulcan

Accompanying the GA diagram from your recent post:

By the time a new Atlantic brochure was competed in September 1953, in time for the Farnborough Show, the engines had been moved further away from the fuselage.  This allowed the leading edge wing roots to be blended in to the fuselage.

There's a third pic with seating arrangements, showing the same nose as the one in your most recent GA diagram:

The seating arrangements for the September 1953 Atlantic with & without a bar.  Note again rearward facing seats.

[rickshaw]

Robert,

Looks loads better with that nose! How about combining the two?

I've always quite liked the Comet nose.  I think its a lot better looking than the Boeing nose.

[PR19_Kit]

I've always quite liked the Comet nose.  I think its a lot better looking than the Boeing nose.

Absolutely! 

[kitnut617]

I'm not too keen on the layout which has the engines at mid span but I have to a agree, the Comet style nose does appear a lot more streamlined.  (side note- the Caravelle got the Comet nose too).  I think I'll stick with what I have gathered for the model though, I've asked Denzel at Welsh Models a couple of times if I could buy certain parts from his kits or rejects that didn't quite make the grade but he said he doesn't want to break-up the sets, apparently all the forming and casting is done elsewhere so no spares or rejects are around.  I've got one of his Comet Mk.1 kits to do (RCAF of course   ) so I'll have a look at it and see what I can do with it but it's not one I'd want to cannibalize.  Besides it would be a hell of a job to try and make the Comet style nose for the wide-body.

[kitnut617]

Thats the one Robert.  In the Aerofax guide it states the first pic you've got above as being from June 1953, the one in your recent post dating from September 1953.  Phil & Tony Butler are the authors, I know you're in contact with Tony so it might be worth calarifying it with him?

I'll send Tony an email and see if I can get this clarified Simon, I'm sure the fellow I contacted who used to work in the Avro drafting office at the time told me it was the other way around.  I'll send this fellow an email too, but it was quite some time ago that I had chatted with him so I'll have to see if his email addy is still current.

Incidently, the Avro Atlantic was featured in a Neville Shute book ----