Third time lucky. A definitive Javelin? Airfix 1:72

[TeeELL]

Some of you may have been following my Javelin build.  I have had to call it a day on that build due to a major painting error on my part.  Fortunately, I have spare Airfix FAW9s but I will use my development ‘mule’.  Having visited The Jet Age Museum I noticed that features on the aircraft showed that the old Heller/Airfix version was wrong.  As a consequence I have decided to leave the previous build and start afresh.

My sources of reference are the LIDAR created 1:48 Airfix Javelin and an aerial photo of a museum aircraft.  The new build will require the 4 pitot heads of the artificial feel system re-positioning along with the pylons and gun ports.

[badger]

Sorry to hear about your problems with the previous build, especially given that you had managed to rescue it from the first paint issue.

 

Am excited to see where this thread goes to though.

 

All the best

Ben

[TeeELL]

8 hours ago, badger said:

Sorry to hear about your problems with the previous build, especially given that you had managed to rescue it from the first paint issue.

 

Am excited to see where this thread goes to though.

 

All the best

Ben

Thanks Ben,

  I confess that I’d always assumed the kit was accurate (or as accurate as tooling from that era could be).  That said, the FAW9 version hails from 1994 and I don’t know how many were under cover back then for measuring.  Still, I have a FAW9 almost on my doorstep and now that I’ve started identifying errors in the kit I can dig out my tape measure - I shall be hanging on to the 1:48 scale version a while longer as well.  I’ve harped on about it being created from LIDAR scans of my ‘doorstep’ aircraft.

In addition, the staff at Newark Air Museum are also very helpful with access to their FAW8.

[TeeELL]

Just at the moment I am studying the tailplane/elevator 3D print - the real thing has quite unsubtle hinge points - so I am giving ‘my’ print a little more definition in those areas.  I’ve also been able to do a bit more ‘design sanding’ of the elevator to reduce the real sanding.  I am doing the same with the ailerons but I am leaning towards leaving the ‘hinges’ in place on the model and creating cut outs on the aileron - it is a bit more work in the cutting and filing stage of the outer wing but will be more effective because, again, those areas on the aircraft are very obvious, almost agricultural to be honest.

I’ve realised that the pylons, certainly the inboard, are in the wrong place; even with the overly fat aftermarket underwing tanks fitted on my first attempt at this kit the U/C door to tank side is significant and certainly precludes any need for cranked inner pylons.

As I correct the errors I shall list what I’ve found and what is required to correct them in case anyone else wishes to undertake the same.

oh, daft as it might seem, I will also take a look at the other Javelin kit I have (Plastik is it) in case they got dimensions right or have better examples of parts.

[TeeELL]

Back in 2019/2020 there was extensive discussion on the best 1:72 Javelin, all the available models were discussed and the general consensus was the Airfix FAW9 with the HPM rear was the best solution - until it was discovered that there were 2 issues with the HPM conversion:  the most significant being the reheat nozzles (too great in diameter, no inward/downward cant and an incorrectly orientated vent).  Of slightly less significance was the lack of downward change to the rear of the fuselage component.

 

If you are following my previous Javelin build, you will know that I produce my own version of the rear fuselage plug and in one area I am as guilty as HPM - the slight downward change to the very rear of the fuselage.  I’ve banged on about access to the FAW9 at TJAM and my photos affirm the change but it is very difficult to achieve it without compromise elsewhere.  My printed rear fuselage rear end is as close to scale as I can make it and there is no wiggle room for that subtle downward change.  It is all a function of the scale ie actual aircraft skin thickness versus minimum scale thinnesses achievable. 
 

[Gondor44]

I will follow this as I have your previous threads on the subject. I have still not started to build my kit yet, in fact, I have bought a second so I can produce a model of an operator other than my initial choice.

I look forward to your progress.

 

Gondor

[TeeELL]

Back in 2019/2020 there was extensive discussion on the best 1:72 Javelin, all the available models were discussed and the general consensus was the Airfix FAW9 with the HPM rear was the best solution - until it was discovered that there were 2 issues with the HPM conversion:  the most significant being the reheat nozzles (too great in diameter, no inward/downward cant and an incorrectly orientated vent).  Of slightly less significance was the lack of downward change to the rear of the fuselage component.

 

If you are following my previous Javelin build, you will know that I produce my own version of the rear fuselage plug and in one area I am as guilty as HPM - the slight downward change to the very rear of the fuselage.  I’ve banged on about access to the FAW9 at TJAM and my photos affirm the change but it is very difficult to achieve it without compromise elsewhere.  My printed rear fuselage rear end is as close to scale as I can make it and there is no wiggle room for that subtle downward change.  It is all a function of the scale ie actual aircraft skin thickness versus minimum scale thinnesses achievable. 

[TeeELL]

8 minutes ago, Gondor44 said:

I will follow this as I have your previous threads on the subject. I have still not started to build my kit yet, in fact, I have bought a second so I can produce a model of an operator other than my initial choice.

I look forward to your progress.

 

Gondor

I hope I get things right this time!  Of course, I have the U/C parts etc ready from the previous build so that isn’t an issue and I can rescue the pitot tubes.  I will have to recreate the cranked pylons but as they need fitting further inboard that isn't an issue.  I will try and work out the best way to get the outer wing units to match the inner sections.

[Adam Poultney]

You know Airfix will just have to release one next year just because of all the effort you're putting into getting a decent Javelin model!

[TeeELL]

Perhaps Adam.  In the meantime I keep working on the 3D parts for the old version.

[TeeELL]

I have revised the tailplane/elevators to give a bit more agricultural look to the hinge line, I’ve photos taken at TJAM which show the gaps.  In addition, I have redesigned the ailerons so that they use the hinge points of the kit because, again, the gaps are more significant than my original prints achieved.  Minor parts are the 2 supplementary intakes found on the Sapphire 7 aircraft, the original parts aren’t quite right.  Not sure if it is worth designing and printing the artificial feel pitot heads though.

I’ve been studying the canopy and there are 2 canopy arches moulded which don’t exist, I think I will sand them down although, having a couple of spares, I could create the separate canopy sections and have the canopy open - now there’s a thought!

[TeeELL]

I have explained the difficulty of creating the subtle angle changes at the rear of the Javelin fuselage.  This is the real deal:

 

 

as you can see, the metal of the rear fuselage is only 2 layer of thin metal thick.

 

Moving on, I have removed the sellotape holding my development mule together in order to instate it as the basis for this build attempt.  I have started by checking and correcting the position of the 4 artificial feel pitot head positioned on the upper rear of the fuselage.  Using both the scaled overhead photo and the 1:48 Airfix Javelin I have checked the positions of the auxiliary intakes and pitot heads.  Rather than explain all the measurements, here is a photo:

 

It turns out that the in general the positions are accurate with the exception of the outer pitot heads (ph).  The original hole for the outer ph probes is correct for the inner; to get the outer hole positioned a mark 2.75mm out from the centre of that hole.  All in all a far simpler job than I had anticipated.   I shall drill out the 2 holes marked X below and use some stretch sprue to fill.  The positions wherebthe pencil lines cross is where the new holes need to be drilled.

 

The next significan task is measuring the correct positions for the guns and the pylons.  A quick check indicates that, certainly, the inboard pylon and the gun ports are too far out.  If I am permitted, I will take some measurements of the TJAM FAW9 to complement the dimensions of the 1:48 model.

[TeeELL]

I have measured the positions of the gun ports and inboard pylon.  I have used the wing join as the reference point.  The outboard gun port needs to move inboard by 2mm whilst the inboard gun port need to move in by 2.5mm.  The pylon needs to move inboard by 2mm as it is marginally closer to the outboard gun port.  In the photo I’ve written 6mm but it should read 5.6mm.

 

Now to measure the outboard pylon’s position.

[TeeELL]

The outboard pylon is about 0.5mm too far out, but I’ll not do anything about that until the outboard wings are fitted.  The cannon blast tubes are 5” in diameter so approx 1.7mm - I am going to reproduce the tubes with the conical aerodynamic covers I think (saves worrying about drilling the tubes out, especially as the metal is very thin).

[TeeELL]

The vertical view that I am using as a cross reference can be found here:

https://www.thunder-and-lightnings.co.uk/javelin/survivor.php?id=689

 

[TeeELL]

I removed the intake lip for the design mule and created a replacement in 3D, the printed result is oK but very slightly too great in outside diameter,  I shall review it again tomorrow and tweak the drawing if necessary.  I have also copied the profile of the FAW9 radome and designed a 3D replacement - the Airfix kit has a different profile upper compared to lower.  I’ll print a couple tomorrow and do the rhinoplasty on the mule to see how it looks and check the length.

[TeeELL]

After oversleeping and having to rush off to the dental surgery for my hygienist’s appointment, I have returned.  Although the measurements of the intake lips and the cut back fuselage match, there is still a small step between them.  I’ve modified the intake lip very slightly.

Right now I have set the printer running with the Radome, intakes and the cannon shroud covers being printed, it is going to be a couple of hours before I get to see the final results.  Time for a coffee.

[TeeELL]

This is a photo of the 2 parts I designed yesterday for the Javelin:

 

The gaps at the radome join are due to me not being able to file the plastic of the forward fuselage smooth, due to the lump of lead firmly fixed in the forward fuselage.

[TeeELL]

I am going to revisit my replacement rear fuselage because, having looked at the photo carefully and viewed some other photos, there are some very subtle changes in the contour of the upper fuselage before the distinct downward part at the end.  I might be able to revise my ‘definitive’ replacement and make it more so.  
Apologies for submitting this photo again but it is easier to see what I mean with the photo here.  From the fuselage on the right, the top curves gently downwards to approximately where the cammo green changes colour on the fin, it then flattens (or, rather, reduces the curvature) until the final section where it takes the significant curve down to the rear.  That is what I need to see if I can create!

In other news, the cockpit is going together using the Airwaves etched set, the kit instrument panel transfers plus some after market instrument faces.  I am also preparing a second set of ejection seats as I am unhappy with what I had done previously.

 

[TeeELL]

I’ve spent the last couple of hours drawing out the dimensions and angular changes leaving the vital dimensions of the rear as before.  Early indications suggest that it is doable in theory, I just have to persuade it to all connect in practice.  So it is fingers crossed and I will look at it tomorrow.

[TallBlondJohn]

Great work TeeELL. I do plan to buy a pile of updates for my Javelin project, just waiting to see how it all goes together.

[TeeELL]

1 minute ago, TallBlondJohn said:

Great work TeeELL. I do plan to buy a pile of updates for my Javelin project, just waiting to see how it all goes together.

I am happy with the way things are progressing, the rear fuselage I am working on should be OK although I’ve had no complaints from people who have my current version.

Anything I produce for my Javelin will be available and be added to my list of parts.

[TeeELL]

Yesterday evening and this morning have been a little frustrating, having determined that the geometry of the rear fuselage is doable without any compromise in the rear plate and afterburner nozzles, actually achieving the shape has really hurt my ‘little grey cell’.  After watching a couple of You-tube videos, I think I know what has to be done!  By way of a mental break for my overworked brain cell, I broke out the sanding sticks and made a start on removing the raised panels.  The ‘silver’ plastic is great if you are of a mind to scribe furrows, as there is a ghost line remaining - I won’t be doing that.  In addition to removing the raised panel lines, I’ve thinned the wing trailing edge.  Jobs yet to do before construction commences: cut off the ailerons leaving the original hinge points and cut out the rectangles for the airbrakes.

 

During the painting of the previous Javelin I used foam and blue-tac to protect the cockpit; unfortunately the small raised nav's display was damaged during handling.  I’ve spent a few moments designing a cover that will fit into the cockpit and over the rear display - it is printing just now.  This would not really be necessary if I were to have the canopy closed (I don’t know why I didn’t do that previously?) but I am going to use the 2 canopies to make one with the 2 sections slid open - well that’s the plan.

 

That’s all for now folks

[Gondor44]

You do like to make a rod for your own back don't you?

 

Mind you, it does mean some of us end up benefitting from the fruits of your labours

 

Gondor

[TeeELL]

45 minutes ago, Gondor44 said:

You do like to make a rod for your own back don't you?

 

Mind you, it does mean some of us end up benefitting from the fruits of your labours

 

Gondor

To be honest, this non-essential stuff is just ‘stuff’ I think about to make life easier!  I really need to focus on the rear fuselage, I will get there and, hopefully, will be to the benefit of anyone with the Airfix 1:72 Javelin in their stash.