F7U-3 Cutlass conversion

[Scotaidh]

Thats one of the joys of this forum mate.
We all feel free to join in and tell each other how we would build each others projects, pointing out where, in our opinions, the other has gone wrong.
And mostly it doesn't matter because in Whiff world you can justify almost anything.

Yes, I get that, and I hope no-one took that as "go away and leave me alone", because I enjoy the by-play and comments.  I've gone down some truly strange rabbit holes because of the chats on this site.    And, I've enjoyed every one! 

[NARSES2]

Thats one of the joys of this forum mate.
We all feel free to join in and tell each other how we would build each others projects, pointing out where, in our opinions, the other has gone wrong.
And mostly it doesn't matter because in Whiff world you can justify almost anything.

Yes, I get that, and I hope no-one took that as "go away and leave me alone", because I enjoy the by-play and comments.  I've gone down some truly strange rabbit holes because of the chats on this site.    And, I've enjoyed every one! 

But did the rabbits ? 

Always remember the unofficial motto of the site "it's my model" 

[zenrat]

Even if you did come out and say "go away and leave me alone" and then airbrushed it in letters six inches high on the inside of our screens some of us STILL wouldn't get the hint and would continue offering advice.

[Charlie_c67]

Even if you did come out and say "go away and leave me alone" and then airbrushed it in letters six inches high on the inside of our screens some of us STILL wouldn't get the hint and would continue offering advice.

Now go and paint it in the colours of the Republic of Biafra... you know it makes sense 

[Scotaidh]

Even if you did come out and say "go away and leave me alone" and then airbrushed it in letters six inches high on the inside of our screens some of us STILL wouldn't get the hint and would continue offering advice.

Now go and paint it in the colours of the Republic of Biafra... you know it makes sense 

You jest, but that might actually work.  I was in Nigeria in 1970, just after the Biafran War ended - I had classmates who had chunks of shrapnel and pieces of mortar bombs as souvenirs ... I didn't have anything to do with all that, as I was in the centre of the country and never went to the contended area.  Biafra was still a very touchy subject, though - not one for whites to talk about in public.

[Scotaidh]

When I was a child, I never dreamed how useful Lego <registered trademark> would be in my later years. The dark bit behind the engine bulkhead is a locating block so the bulkhead has something on which to positively adhere. In a useful bit of serendipity, the section of the "For Sale" sign that provided the bulkheads was part of the black lettering, so no need to paint!



I used a bit of Evergreen "angle iron" for the location blocks. I know that in the F-4 Phantom there's about 6 feet or so of trunking ahead of the turbine face - does anyone know a) if that's important; and b) why so?

[Scotaidh]

A bit of basic research on Biafra revealed that their air force aircraft were simply painted green over-all; and they wore roundels, thus:

Their aircraft, for anyone interested, consisted of
2 B-25 Mitchells
2 B-26 Invaders
1 DC-3
1 DH Dove
5 MFI-9B/Bolkow BO 208
4 T-6G Texan

The colour schemes varied greatly - different shades of green in wavy patterns; all green under black squiggles; black and green wavy patterns.  At least one of the Mitchells featured a shark-mouth.

[Scotaidh]

I believe the important thing is the shape of the inlet and the trunking to the turbine for supersonic flight.

I'm sure you're right.  I used to work with a bloke who was a maintainance chief for United - what he doesn't know about jet engines is - well, it might be worth knowing, I guess, but I'd bet on him knowing it if it was important.    Unfortunately he got hurt on the job and is convalescing, so I can't ask him.   

In the meantime, there's this:



I neglected to get a picture of the exhaust nozzle before I operated on it, so this picture of the instructions will have to do. It was intended to hold the exhaust nozzles and complete the rear end of the fuselage, but it is now much too small to do so. I snipped off the outside round parts, leaving only the centre bit that projects between the nozzles - but it, too, is too short due to the increased diameter of the new engines. I cut it in two horizontally, and put in a filler to make the part work.



This is the filler bit - a small length of Plastruct tubing. I guess it'll be a fuel dump or something - might have to lengthen it a bit! I'm thinking that perhaps the new engines will require some additional cooling around the rear ends, particularly the after-burners - much like the Phantom FGR-1s & -2s have that aux cooling door. I'm sure I can source some vents from somewhere ... IIRC, StarShipModeler's store has a nifty line of exhaust ports ... hmmmm

[TheChronicOne]

This is awesome. Keep going!!! 

[zenrat]

It's so neat and tidy.
So different (and this is not a criticism - we all work differently) from the "stuff it with filler" approach.

[Scotaidh]

Don't worry - there will be plenty of putty to come.    I first have to get over this sinus infection ...   

[Scotaidh]

Styrene strips in place - some adjustment is required, but it does cut down on the dreaded PSR. Two more to do, underneath. Each one has to be measured, cut, and inserted/placed separately.



As you can see, my cuts aren't all that precise. Now I know the dimensions of the fuselage, I think I'll put in another frame-plate. Then I can fix my intake trunks to that, and no-one has to see the penny whistles. After all, they're just there to determine the final size of the aircraft.

[Scotaidh]

Better late than never, I guess.

Some comparative data for the two engines concerned. I know there are other figures for these engines, but these are representative. I find it interesting that the J79 has double the Thrust-to-weight ratio, more than double the Air Mass Flow, and all for much less fuel consumption. I must discuss this with my jet engine guru, on Monday.


I decided, after looking at the fuselage shapes, that further surgery was necessary to avoid me having to sculpt complex curves. The two tubes will be re-skinned to fill in the cut-out area. The intakes will then be added on the front, and then I can worry about the nose - which may also have to be modified. It never seems to stop!


Just another view of the damage.

[Scotaidh]

The tubes in place. As you can see, I had to trim them a bit .


Speaking of the cut-out piece, it's come apart at the seams.  Right now, the only thing holding that lot together is hope and the internal intake trunking.   I guess it's time for the yet-to-be-fabricated internal reinforcement plates.


Onward, as they say. Who doesn't need extra splitter plates?


One problem, highlighted by Picture #16, was how to build up the fuselage skin over the extension. I cut a 1" wide strip of very thin plastic sheet, glued down one end, and am wrapping it around to create a very strong skin. The wing roots will have to be putty, I guess - Aves Apoxie, for choice. I'll also use that to fair in/over the fuselage joint.

[NARSES2]

I'm enjoying watching this come together