Wide Body Avro Atlantic

[Brian da Basher]

That nose fits like a glove!

You've really got my interest now!

Brian da Basher

[kitnut617]

I think I'll settle on this layout for the tail cone, it's not totally right compared to the brochure sketch though.



I worked out the distance from the ground to the underside of the fuslage (assuming the fuselage has a horizontal stance when on the ground) which dictated that the fin/rudder had to be a tad larger than what the Vulcan had which is understandable. The extra size I'll just add it to the bottom of the fin I think.  Now to work out the templates for the cones, there will be four half cone of one shape or another.

[kitnut617]

Before I cut the inner wings off,  I've measured the AoA the wing is set at on the Vulcan, which is 5.5 degrees. That's the centerline of the chord to the centerline of the fuselage.  One thing I'm certain of, it can't be that on this Atlantic, the main wing spar would effectively block any passage through the cabin and there's no way you can put a step-over to get over it.  I'm thinking maybe 3.5 degrees but until I can trace the root chord and get it in the computer I won't be able to tell for sure.Looking at the sketch in the brochure would seem to confirm that though.

This pic shows what I mean,



I've traced this outer chord and added it to my side profile and even though this chord is the smaller one it was still way up into the cabin area.  Measuring the kit where the main spar would be right next to the fuselage I scale it at 6'-6" deep, the deepest point of the chord scales to 7'-6" but this isn't where a spar runs through. 

[Brian da Basher]

Wow that's some seriously impressive draftsmanship, Robert! I always appreciate a very thoughtful whiff.

You're more than one up on me. I would've taken the cheesy way out and just used the 737 tail.

I'm really, really enjoying this one! Thanks for the update!

Brian da Basher

[kitnut617]

Hey Brian, my drafting is assisted by things you can get off the net, I had forgotten I got a 3-View of a 737 in Autocad form so it was relatively easy to 'copy & paste' what i needed    (we really need an 'embarressed' smiley)

I did trace the shape first and it came close to the 3-View so I know the Combat Models -100 is fairly accurate.  The tail I just traced around the kit part then modified it a bit.

Anyway, I've decided to do a very subtle re-profiling to the underside of the 737 fuselage to make it look a bit more like the Atlantic.  The transition from the nose tip to the bottom of the fuselage in the side view is much more smoother.

This pic is of how the 737 is, the bulged look to it is because the wheel bay is in this location.



I've re-worked the drawing profile to look more like the Atlantic and to make the profile more gradual, I've had to make a keel that will hold the shape, this is helped by the fact the vacuform plastic is very flimsy.  But I needed to do something else while I did this, put the new wheel bay in too. I've used the Vulcan wheel bay for this and I've attached the keel to the front of it.  Actually it's the back of the wheel bay, but because the front u/c retracts forward on the Atlantic, I've turned it around.  The u/c leg will now be just in front of the radome.

[kitnut617]

There was a small problem of trying to keep the keel/wheel bay in the correct orientation so I had to make some bulkheads and such.

Here's a couple of pics of the keel/wheelbay assembly.




I cut myself a round bulkhead which fits just in the 737 fuselage, then marked out where it will straddle the wheelbay. This was all glued together with a stiffener to hold the bulkhead square to the wheelbay.




Then it was just a case of glueing the assembly into the fuselages.




You can see the slight difference the new profile is now

[kitnut617]

A 'before & after'

[kitnut617]

I can't lay claim to the idea Duncan, all the Aircraft in Miniature kits have a keel, even the DC-9 one.  These though are a full keel top to bottom and also have a little flange all around the keel which is used to glue the two sides too.  Thanks for your comments --

[kitnut617]

Another view of the keel, I tapered the flange because as you get to the nose the fuselage sides become closer to the center. I rounded off the flange too, to conform better with the sides.

[Brian da Basher]

This is some seriously sophisticated whiffery, Robert! It's really beginning to take shape and thanks for keeping us up to date with the pics and the play-by-play!

Brian da Basher

[Taiidantomcat]

That is some surgical precision!  Superb job so far 

[kitnut617]

So I got some more done, in between bouts of intense RW stuff.

I've duplicated the starboard side of the fuselage but not the 737 bit, leaving that off for a while because I want to detail the cockpit. I've now glued the two sides together.

I'm going to copy this for the cockpit, it comes from the Welsh Models 1/72 737-200 kit:



I'll either do it with styrene, or do something I've never tried before, ""dropping it in rubber"".  I might just give the casting a try because I have a lot of other things I wouldn't mind doing a casting of.

So I started on the tail end and the plan was to use as much of the B-36 as I could.  Unfortunately, the compound curves of the B-36 tapering don't match up very well with what I've managed to develop for the Atlantic.  So I chopped the tail off right where the tapering starts.  I added in a bulkhead right where I chopped the tail off so I had something to attach the tail section.



What I did was to make a keel in the vertical and horizontal, then filled it with some formers.  These I had to work out what the correct shape would be for each station.

[kitnut617]

To make the formers I developed them in my CAD program, then printed them onto a large sticky backed label. Originally I was going to do it like this;



but then got to thinking 'that's a lot of cutting', so I joined them up like this (these are not round but eliptical);



where I was able to do one cut for the lot of them in one direction;



I then developed out the skin, this isn't a simple cone shape as all the sides have a compound curve so the end result of the development looked like this;



Which was then printed on the sticky label, stuck to styrene and then cut out.



Each one of those little 'fingers' has a slight curve to each side which when the large end is rolled into a tube, the 'fingers' form the compound curve of the fuselage, That's what the plan was ---

[kitnut617]

I marked the center finger and then glued this to the top of the vertical keel, then worked my way down each side glueing each finger to the next one.  I got very involved with this and forgot to take some pics of what I was doing (I'll do it when I do the bottom half) but in the end it worked out, --- fairly well ----





You'll notice I've used the small radome from the Vulcan, I cut some slots into the bit that is inserted into the tail and used this to hold the keels in shape at the very end.  Plus the ledge works as a good point for collecting and glueing all the fingers ends.



Before I stated on the skinning I added a brace because the whole keel assemble would twist if I wasn't to careful, it did stiffen it up quite a bit.  This was purely for assembling purposes because now the the skin is on the whole structure is very stiff.



I've given the skin a precursory sanding just to take the rough edges off, did this just so I can see what the shape turned out like.  It won't get the full sanding until the whole tail is skinned.

[jcf]

Cheater. Yer s'posed ta spile each 'plank' individually mate. 
Ye'd never make it as a boatbuilder.

Nice work Robert.