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I wonder? ………

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Have I wasted a few hours?  Mind you, there was nothing on the tellybox.  This particular version is designed to have a hypodermic needle inserted into the body for strength ( just in case I cannot find a 19 or 29 gauge needle).

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How to waste a couple of hours …..

Looking through my collection of Javelin photos I found a couple that gave me cause to review my ‘open airbrake’ drawings and prints.  Of course this is a waste because it is a rare sight to see A/Bs extended on the ground and the demand for such 3D prints would be negligible (I will pose one of my builds though).  
I re-worked the 2 A/B components so that they could be fitted together accurately and, more or less, in the correct position.  Having saved the files it was time for breakfast.   That was when the revelation occurred!   Instead of 2 fiddly separate items, why not combine the 2 drawings and see if that would print.  This is what the CAD looks like:

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I think that is about as good as it can get in this scale.  The print might prove that bits need thickening but I think it looks pretty good?

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Mixed results with the airbrake printing.  The ‘flush’ airbrake replacement is still not printing effectively so further tweaking has taken place.  I am, however, pretty pleased with airbrake ‘out’ combined print.  I’ve not recessed the wing as the fuselage halves are set up to ensure the shape of my replacement rear end fits as well as I can possibly make it!

Here is a taster of the airbrake out print:spacer.pngspacer.pngspacer.png

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Printing further revisions which include a slight taper on the ‘airframe components’ of the airbrakes to ensure they don’t foul one another on installation.  Yet another attempt at a reasonable representation of the closed airbrakes, slightly beefed up retraction unit on the nose leg and, most importantly, my first attempt at getting the shape of the fuselage join correct.

Details on success, or otherwise, to follow - in about 90 mins! 

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I have trimmed one of the nose wheel legs and the following photo shows it next to the Airfix original together with a variety of variously supported versions.

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That previous post should have been posted about 4 hours ago!

 

Anyway, sorry about the extended delay I was at Air Cadets teaching pilot navigation on a VR flight simulator!  Home now and the bits are toasting in front of the UV lamp.  Finally, I seem to have achieved  the ‘airbrakes retracted’ print, although I need to test them under a coat of primer and paint.  The retraction unit for the nose wheel leg still looks a bit too skinny but I think I have the definitive airbrakes out print.   
 

I will post some photos next but need to remove the items from their print platforms first.

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I now have the ‘definitive’ airbrakes out print so that can go in the completed file!  The airbrakes flush is OK but not sure if they will stand up to paint so I will check before declaring them ready.  The nose wheel leg is pretty much there although the retraction section still needs a bit more meat, I was doing really well removing it from the supports but tried to remove the little nibs with a scalpel- that was a bad idea!

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in the photo are the two airbrake options, the flush will be more obvious in the next photo.  The oval on the fuselage is supposed to be the exact shape of the rear fuselage ‘join’.  To the right are the latest modification to the airbrakes to ensure the base doesn’t foul when fitted - compare with the thicker base of the previous iteration outside right.  Finally, on top of the fuselage is the nose wheel leg which is fine - right up to the point where I broke it!

 

here is a photo that should show the flush airbrake units:

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Sharp eyed amongst you may have noticed a slight curve on the end of the ‘flush airbrake’ part, one of the vagaries of 3D printing.  It is annoying little issues like this that keep me on my toes!  I am at a loss as to why the same effect isn’t seen on the earlier ‘unuseable’ versions! 

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A check fit of the oval in the rear of the fuselage has shown it to be a bit too big.  This time, I have drawn around the forward end of the section I cut off!   I will get that printed off for another check piece.  The actual shape )the kit) is not symmetrical unfortunately.

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I beefed up the nose gear a little more and did a few extra refinements.  I am now happy with the end result:

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The oval printed template is very close.  The top surface is as good as it gets, I need to do a little work on the lower starboard ‘corner’.

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I have done 2 tweaks to the template and I am just waiting on, what I hope is, the final iteration.  I have done a ‘proof of concept’ that I can use the LOFT tool to create the back end, it is a little more difficult because the template is slightly out of shape due to the actual shape of the model!  I am going to have to hope that I get it right.  I might see if I can develop the slight downward curve at the very rear of the fuselage.

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Well that didn’t work!  I wrongly assumed that the new drawing would size correctly using the exact same ratio.  I was very wrong, no idea why!  Literally ‘back to the (electronic) drawing board’.  All a bit too late now.

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It is bloomin’ amazing, just as I thought I knew what I was doing then Fusion360 throws a curve ball.  I have had a couple of practice runs ‘lofting’ from the template to the rear plate and it worked perfectly thus lulling me into a false sense of success!  I have, just now, tried lofting with the revised template and it all went pear shaped (almost literally).  I have to look up creating the ‘rails’ along which the lofting will follow.

 

Lofting is creating the ‘fill’ between two shapes ie to achieve  the rear body of the Javelin the forward shape (the fuselage join) is designed, then the rear (jet pipe exit) designed. By selecting one then the other, Fusion will fill in between the two - easy peasy, except when it is not.  Fear ye not dear, patient, follower of this nonsense, I will prevail (even though my fingers are very firmly crossed).

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We appreciate all the work you're doing, but for me there is no rush. I've been waiting several decades for a good 1:72 Flatiron, so I think I can wait a bit more. Although I am getting pretty old...   :)

 

Cheers,

Bill

 

PS. You know I hate re-scribing right? Any chance you could 3D print the other fuselage and wing bits?   :)  :)  :)  :)

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Bill,

  I have no plans to re-scribe my Javelins, I will remove the raised panel lines but in 1/72 panel lines simply cannot exist!  Indeed, even making the airbrakes ‘obvious’ on the replacement ‘flush’ units is taking it a bit far!  I certainly cannot fathom this ‘pin wash’ the panel lines malarky.  Still, each to their own.

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So far I am happy with the nose gear, although I’ve yet to try and fit a reinforcing Hypodermic needle down the hole in the leg.  I am very happy with the ‘airbrakes out’ prints - right up until some smart a*se tells me the angle is wrong!.  I am happy with the replacement nozzles for the High Planes conversion.  The latest ‘flush airbrakes’ look OK as well.  So, it is just the single most important part that is not ‘playing ball’ just now!

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1 hour ago, TeeELL said:

I have no plans to re-scribe my Javelins, I will remove the raised panel lines but in 1/72 panel lines simply cannot exist!

 

I was just joking. I agree completely - I gave up panel line washes a long time ago. In fact, I terminated my membership in the Modelling Gimmick of the Month Club.    :drunk:

 

Cheers,

Bill

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Good for you Bill.  I did see a clearly defined panel line - turned out to be moss and algae growing in the panel line on an outside museum exhibit!

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It is quite probable that this will be one of my last posts for a couple of weeks - ‘thank goodness for that!’ I hear you say.  I have been studying youtube videos on how to resolve the issue I have with Fusion 360 not joining the profile stages (lofting) to create the rear fuselage component.  If time permits, I will have a go today.

Elsewhere, I was pointed in the direction of ‘dosage needles’ and, courtesy of a well know ‘rain forest’ supply company, have ordered a small number of 19G stainless steel ‘blunt’ needles.  These are 1.04mm external diameter and my plan is to trim and fit one into a revised nose-wheel leg to provide strength and, as I have mentioned, provide the shiny bit of oleo - but that is for a few weeks hence.  When I say ‘revised’ nose wheel leg, I will need to add a sacrificial support to the rear of the leg so that I am not reliant on the scissors mechanism to hold it together!

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Yes I know “what happened to ‘last post for a couple of weeks’?”  Well I did some adjusting to the 3 profiles that make up the rear fuselage and got a better ‘loft’, well actually got a ‘loft’ - not quite there yet but a significant improvement.

 

The plan with the nose wheel, if it works, is to insert the stainless steel needle flush with the lower wheel yoke and super glue into the upper and lower halves, remove the support ‘thing’ and finally trim the top to length leaving a stub to fit in the U/C bay positioning recess.  OK?  Got that??

 

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  • 3 weeks later...

Well now, 

 after a fabulous fortnight in Cuba (including overnight stays in Frankfurt at either end) I am home.  Looking forward, I think, to getting back to resolving the Javelin ‘rear’ and trying out the reinforced nose-leg idea.  I hope to take and display examples of the parts I am creating to SMW, Telford - if my Club is OK about it.

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Today I have been doing some fine tuning of parts.  The nose wheel leg required some adjustments to ensure the separate wheel fitted properly, the latest iteration of ‘fuselage join’ has been blended into the rear fuselage component; this is very difficult because the fuselage, at the cut, is not symmetrical, with variations in curve radii, and I want the part to fit with minimal filler/blending.  This component will be printed for test fit before I refine it any further.

in addition, I have drawn ‘seam free’ intake tubes that should accept the intake bullet/Compressor face component.  I still need to add the 6 petals that are to the rear of the turbines but at present I only have the design from the Airfix 1/48 instructions as a reference.  I am hoping The Jet Age Museum engines will give me a better idea of the look - I will have to nip over there soonest.  That said, in 1/72, does it really matter?  Yes, of course it does ……… Lol.

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