The P.1121 get's it's feet wet

[George the Cat]

Well done so far Gondor. 

[Gondor]

There are advantages and disadvantages to having plans to work with when building a model. The advantages, assuming the plans are correct, are that you can build an accurate model. The disadvantages are exactly the same.

In trying to match the Whirlybird kit to the plans I am working from, I have found several things that are different. The latest is that the length of the kit's fuselage is too long.



The above picture shows the undercarriage bays lined up with the drawing. As you can see, the tail is too long, and thereby hangs a tail,



Approximately one scale foot too long, but it's not as simple as cutting it off the rear of the fuselage. That would be far too easy. If you move the fuselage forward that foot, the bulge from the transonic area ruling of the fuselage matches the drawing far better, as well as the location for the tail surfaces aligning, this will, of course, move the rest of the fuselage forward a scale foot. The removal of the foot will have to be to the rear of the fuselage, after the trailing edge of the wing, as moving the wing root is another different kettle of fish. The removal of the foot also has to avoid the main undercarriage bays as they match with the intake and nose undercarriage on the drawing.



This is getting rather complicated, not helped by my wanting to add the details I have already started on. I am now thinking that perhaps I should build the interior, as best I can, and then skin that with as much of the kit as possible? Or at least approach this build in something like that. So with that in mind, if you are into stocks and shares, perhaps you ought to invest in shares in fillers and sandpaper.

Gondor

[Gondor]

I have finally found some plastic tubing near enough to the diameter given in the drawings for the Reheat section of the exhaust, located between the rear tailplanes of the aircraft.

I will be using a section of the item below.



You may well be wondering what on earth it is, how did I find it, and what is it from?

Let's start with how did I find it. I was measuring the drawing and found that the diameter given in the drawing for the reheat section of the exhaust was roughly 1.5cm, roughly 10/16". So a search of the internet and a couple of my favourite modelling shops resulted in tubing half that diameter. Next thought was fuel tanks, which can be big and of constant diameter for some of them. I work in 1/72 and am now wishing that I had some 1/48 fuel tanks as they might have been close enough, but I don't, so that couldn't work.

What is it from, and what is it? Then I realised that I had a 1/72 Stratos4 specific sprue lying around. For those who don't know what that is, it's a Japanese cartoon which uses an aircraft based on the TSR.2, Airfix released both Season One and Season Two styled markings of their TSR.2 kit with an additional sprue to convert the aircraft into the Stratos4 machine, which includes the missile parts in the above picture. This is one of those times that I am glad I hardly ever throw any parts away.

So, as it is just after ten in the evening, I will start cutting things up tomorrow, and I shall sleep well tonight knowing that another piece of the puzzle is in place.

Gondor

[Weaver]

LOL - my Stratos 4 rocket is currently hanging in the middle of a baby's aerospace-themed mobile...

[Rick Lowe]

LOL - my Stratos 4 rocket is currently hanging in the middle of a baby's aerospace-themed mobile...

  Starting them early.. 

[Gondor]

After a bit more hacking around I have got this far





More work required, but it is getting there.



Still, you see what I am aiming for, more trimming of both the ducting and the intake, but it's more progress.

Gondor

[Spino]

There are advantages and disadvantages to having plans to work with when building a model. The advantages, assuming the plans are correct, are that you can build an accurate model. The disadvantages are exactly the same.

In trying to match the Whirlybird kit to the plans I am working from, I have found several things that are different. The latest is that the length of the kit's fuselage is too long.


Approximately one scale foot too long, but it's not as simple as cutting it off the rear of the fuselage. That would be far too easy. If you move the fuselage forward that foot, the bulge from the transonic area ruling of the fuselage matches the drawing far better, as well as the location for the tail surfaces aligning, this will, of course, move the rest of the fuselage forward a scale foot. The removal of the foot will have to be to the rear of the fuselage, after the trailing edge of the wing, as moving the wing root is another different kettle of fish. The removal of the foot also has to avoid the main undercarriage bays as they match with the intake and nose undercarriage on the drawing.

Suppose you just use whiffery to explain away that extra scale foot.   Extra stage on the afterburner?  Stretched fuselage for more electronics?  When I did my F-107E build I failed to print the forward and aft sections of the model at the same joint area, so the plane ended up being a scale foot or two longer than the prototype would have been.  Totally fine for me since it was always intended to be a further developed version (I seem to recall one of the F-105 variants got longer IRL too, and not because of adding a second seat, something about a new radar in the 105D vs the B maybe).

[Gondor]

To help me model the engine intakes, I opened up the upper forward fuselage. While I was doing that, I decided to cut a scale foot out of the rear fuselage.



The upper forward fuselage cut was made where the front of the engine is.



And the rear fuselage still matches up with the main undercarriage bays.



Well, the front of it does anyway. This will not be a problem as the kit being a late Wirlybird production of the Maintrack kit, the undercarriage bays are resin items with the main bay having bulkheads at the front and rear. I will probably have to open a hole in the rear bulkhead for the engine exhaust, but we will see.

The big advantage to all this cutting up of the fuselage is that I can assemble the centre section and drop in the nose undercarriage bay and the intake ducting, as I want to check their fit. One thing I have realised is that the diameter of the Lightning intake is smaller than the engine front. I will pack out the gaps with parts of the engine cowling I used for the front of the engine. Filler should take care of the rest.

Gondor

[overscan]

The rear fuselage differs between the Gyron, Olympus and Conway 21. So any deviation could be easily explained.

[Gondor]

The rear fuselage differs between the Gyron, Olympus and Conway 21. So any deviation could be easily explained.

That could simply be the answer in this case. The Maintrack based Whirlybird kit being a land based version with one engine type, while this is the Naval version with probably a different engine.

[Gondor]

I have encountered a bit of a problem, which I am looking for some suggestions to get around.

I started to assemble the parts for the exhaust, running from the rear of the engine to the rear of the airframe.



As you can see from the above picture, I have a length of plastic tube, the rear bulkhead for the undercarriage bay, with a hole cut out by me, and the undercarriage bay.

The problem is related to the undercarriage bay, which is a partial cylinder of resin with the bays being recessed into the external surfaces. The problem is that part of the resin needs to be removed. The two pictures below show the area.



Rear end elevation



Plan view, rear to the left.

The main problem is coming up with a safe and easy method of removing the shaded section in the last picture, to the depth in the previous picture. More could be removed, but in the vertical axis only; otherwise, I could easily find myself cutting into the undercarriage bays.

I have limited tools, and the part is not exactly an easy shape to hold mechanically.

I have lots of other parts to work on, so it's not as if this needs to be done this weekend.

Gondor

[scautomoton]

I would just use a small round or half-round file

[Rick Lowe]

I would just use a small round or half-round file

To start with, sure - but it ends in a vertical face, so that end will be a problem.

You may have to carefully carve, or scrape the last bit.
You can't cut the part completely in half and use the file idea? Through he bays yes, but you could rejoin and fill/fix?

If you had any sort of drill, I'd suggest a grinding bit.

[Gondor]

I would just use a small round or half-round file

To start with, sure - but it ends in a vertical face, so that end will be a problem.

You may have to carefully carve, or scrape the last bit.
You can't cut the part completely in half and use the file idea? Through he bays yes, but you could rejoin and fill/fix?

If you had any sort of drill, I'd suggest a grinding bit.

I have drill bits, but no grinding bit that would enable me to go deep enough from the end. I am thinking of drilling on the flat surface multiple times, chain drill technique, across the whole rectangular surface with the depth of the drilling corresponding to the  cross section of what I need to remove when looked at from the end. Lots of swarf as a result, but less dust and I should be able to cut away what's left before filing the surface smoothish.

[Weaver]

What I'd do is stick a ball-ended cutting bit in my Dremel, then take the material out in multiple shallow, careful passes. Then use a barrel-shaped cutter with end cutting surfaces to work up to the blind end, then finish off manually with a chisel blade in a craft knife. Of course all that only works if you've got a Dremel...