A Trilogy of Twinfires

[zenrat]

 

[steelpillow]

There's more of the "middle wing" than I expected. No guns in it? There'd be a lot of space for fuel.

Yes, the Pacific interceptor is a long-range concept, able to take the war out to the Japanese before they reach their targets. It also had to be high-altitude, as some of the Japanese planes flew above the Mk VC's operational ceiling. Both militate a high-aspect-ratio wing of moderate loading (i.e. no extra guns), and as much fuel as the thing can stagger into the air with. But of course, much of the centre section is occupied by wheel wells and ducting and other gubbins, so its fuel capacity is not as massive as one might imagine. Hence the other tanks mentioned.

Most Twinfire whiffs are conceived as dogfighting, low-drag speed machines and centre sections are unrealistically cropped short to the point of being practicable only as a thoroughbred short-distance racer with all military equipment stripped out (as is my Twinful).

However maximum altitude is reached where the stalling speed and maximum speed coincide. This design improves each a little. I sized the centre section to give a little more lift than an entire standard Spit which, like all planes, loses a lot of lift out near the tips (In the case of the Spitfire wing, these tip issues get complicated, so I gloss over that here). Area is not much more than half as much again as a single wing but, because it has no tip losses, lift is over twice as much. Also, not only is frontal area less but again, tip vortex drag is eliminated, so max speed is also a little higher - just enough to catch that Ki-46.

Airframe weight is the critical balancing act, keeping the loading and hence stalling speed low, while keeping stiffness adequate. In fact the stiffness is only barely adequate and it flexes noticeably when manoeuvring, hence the affectionate name, "Wonky Wonder". Caldwell was instructed to carry out only tail chases or diving passes and not to attempt dogfighting! Even so, when he landed afterwards it was bent out of shape and never flew again.

[steelpillow]

Progress has continued, but in a very two-steps-forward-one-step-back kind of way. I managed to knock the MkVIII-VIII on the floor breaking its starboard wing tip - twice. Then, applying a weathering wash, I discovered that the Revell enamel thinners I was using is capable of dissolving unobtainium. So, having reworked the poor thing three times over, what do I do next?
Glutton for punishment, me. I decide that it really needs the detachable tip extensions displaying. Enter a scratchbuilt trestle, a slightly misaligned razor saw and yet another rework. Glue now drying thoroughly before smoothing and repainting.
The idea is that the trestle holds the wing at a comfortable lifting height, so a couple of adequately fit erks can do their stuff. The Spit will of course sit higher once its wheels are on! No plans to do the same to the port tip, so it will display with one shoe off and one shoe on, as it were.
The detachable tip was something that Supermarine did actually consider, owing to the habit of the fixed ones breaking off in combat, but in the end the demand was not that urgent.

[NARSES2]

Neat thought process 

[Rick Lowe]

Well done model, and a good fix to something which Murphy seems determined to keep sticking his oar into... and a second or third repair will never really look as good as the oriiginal build, so well done on the work-around.

[Tophe]

  don't give up, this is so interesting...

[steelpillow]

And after. Tip and trestle after painting up and now fully recovered from the accidents. The rest of the decals are also beginning to appear:

[steelpillow]

Next the sharkmouth decals. Rather than try and flop them around the bulging nose, I decided to paint in the gaping mouths and just apply the coloured bits round the edge. The next step is going to be bad enough anyway...

[Tophe]

Thanks!

[NARSES2]

  

[steelpillow]

All decals now on. Aaargh!'s much as predicted but none proved fatal. The designer had previously been with de Havilland, setting up a Mossie production line in Australia. Had to make a homebrew decal for that one, which is why it is plain black and not steampunk girders.

Technique with the sharkmouths was to cut out the middle to make a vee shape, lay down a base of water with about 20% decalfix, cuss when the decal broke in two anywhere between wetting on the paper and sliding around on the model, keep adding water to stop the decal sticking until both pieces are acceptably positioned, dab off excess water to prevent surface tension from drawing them out of position as they dry unevenly, the cheeky little devils, I know their type, then brush on a generous layer of neat decal fix. Come back an hour or so later, slash any bubbles (pricking can just stick round the hole to the model, so the air is still trapped), dab decal fix on the spot. More dabs where the decal has not sunk into a panel line groove. Five minutes later, press down with tissue to flatten the bubbles out and impress the grooves.

Sharkmouths still far from perfect, as sharkmouth decals always are, but a fine paintbrush can take it from here.

[Old Wombat]

 

[Tophe]

It seems very perfect

[NARSES2]

Looking good to me 

[steelpillow]

This shows the problems more clearly: misalignment of the lower jawline and various teeth due to the inherent clash between plane and elliptical geometries, flakes where decals got abused during the pushing around. All pretty unavoidable. My finest 000 brush is going to have to earn its keep.