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P1067 the Hawker Hunter prototype in 5mm XPS


Simon Chaddock
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I must daft but I just could not resist completing the development set.

It seemed logical to model the prototype as it was nearest to the P1081 predecessor. In addition the protoype would be the easiest to make true scale as the production Hunter had quite a few modifications over its life.

Protoype.jpg.88f9428753aa6f8a785b4c2a142ca2c7.jpg  

It was painted in the same very pale green/blue as the P1081.

The fuselage plan tile printed to the same scale as the Sea Hawk et al.

FusePlan.JPG.f7b3a9f958d18f73ee561b66c5221dad.JPG

This gave the size of the tail pipe, 41 mm, which is exactly the diameter to give 90% of the FSA of a 50 mm EDF and I just happen to have a nice 8 blade one!

The Hunter inlet duct for the Avon is much less restricted than was required for the Nene but this means the EDF will be rather further back.

As before the next task is to design and print the complete duct to be used as a spine so the fuselage can be built around it.

At just 50 mm diameter this duct is going look long. This is just the exhaust part.

ExhaustTube1.JPG.c8ce6777cd3fd0e2451546292283da60.JPG 

There is an EDF down in there somewhere!

EDF50mm.JPG.cf9c8b1e1d204997b36689379cf427c8.JPG

This could take some time. ?

 

 

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All most another full day printing the inlet duct or rather trying to 'adjust' the design so that it would and that the actual inlets were in the right place!

The CAD image of the inlet duct.

InletFull.jpg.cbc6472cce0508205d3a30366a5c8743.jpg

Much too tall to fit the printer so it is printed in two parts with a section 'submerged' under the bed.

inletPrint1.jpg.93c7c8686ea75a442407af4f5aef0160.jpg

  Turned over 160 degrees and submerged to exactly the right point and the two have will match exactly.

The rear part of the inlet duct that locates onto the EDF.

Inletr2.JPG.df80b3f5d008628e4651c20874d054d2.JPG

Vase printed with a single 0.3 mm wall but still over 2 hours to print. 

As  it turned out even the other half has draw backs so I ended up having to print each 'side' of the inlet individually.

InletFsingle.JPG.09f9f622f01cdf8400ad2fbe9a3ae6cb.JPG

But they are at least symmetrical so it is just a matter of printing the same thing twice.

The next problem is to design and print a bell mouth piece to go on the end on each duct to achieve the classic Hunter 'staggered' inlet.

 

 

Intake1.jpg

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JD 8

I believe it was the single seat development of the P1103, the P1121 that proceeded to the mock up stage as Sidney Camm favoured it. it was privately funded by Hawker (then Hawker Siddeley).

Mockup.jpg.c29a419234306b5f15c8536da7626fb8.jpg.

Quite a bit of the prototype airframe was actually built and being privately funded it was not the property of the Air Ministry so was not immediately scrapped. It went to Cranfield as an instructional airframe.

Cranfield2.thumb.jpg.867b5314f58c4eca7480ebfd7db56bf0.jpg

The wings were lost somewhere along the way but the remains of the fuselage are now at Cosford although not on public display.

No itch to scratch as I built one in 2012 out of Depron and it is still hanging on the wall in front of me.?

24May16.jpg.8d414318d662be0ca339c0a130ccd90d.jpg

 

   

 

Edited by Simon Chaddock
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With the duct glue fully dry I just had to run it up to get an idea of the thrust that would be available. No point in going further if that long duct 'strangles' the EDF too much.

https://www.youtube.com/watch?v=ExYlZsx07Ls

On a 3s although the EDF is 4s capable. Not very scientific but it did blow the door shut!

A second 'hand held' run gave a push that was at least equivalent to that of my other Hawkers. So provided it does not come out too heavy. the Hunter has a slightly bigger span and is a touch longer longer, it should fly well enough.  

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Many hours of planking and I have arrived at this.

Planks2.JPG.95b6f0f2c5511e3554cf3f5f349ff891.JPG

The wing roots still to do.

The un planked area at the tail is to mount the base of the fin. It also supports the tail plane. The area at the front is for the substantial fairing aft of the canopy.

The Hunter has a spine that runs along the top of the fuselage from the fin to cockpit. I will use it to house the elevator servo wire. There will be no rudder.

Tail feathers next. 

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Slowly grinding on. The tail feathers and the wing root skin added.

TailPlane4.JPG.8aa28a547b04a1a35e85cd45dc9cf8e2.JPG

The wire for the twin elevator servos runs inside the hollow fuselage spine.

The fairing aft of the cockpit has to be left open until the wings are in place to give access to bring the aileron servo wires forward to the cockpit area.

So the wings have to be next.

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Still slow although in principle the wings are very simple, identical top and bottom skins and two shear webs but there is a lot of internal skin sanding to achieve a fine trailing edge. Then many clamps to hold the skins together whilst the glue dries.

WingClamps.JPG.3bbbdbc8e02601a562b99c73d89ad4d1.JPG

I don't have enough clamps to do both wings at once but the result is very smooth. The Hunter wing is rather a thinner section than the Sea Hawk so whether a simple unreinforced glued joint will be adequate is open to question.

We shall see!

  

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With the aileron cut out, a servo 'let in' from the underside and the wire extended long enough to reach the cockpit the wings can be glued in place.

WingsOn.JPG.32a60741a4848b0e5d5b95692b6cfb49.JPG

It is precariously balanced whilst the glues set hard enough until it can be moved.

The area in the red circle looks like a flap but it isn't. For some reason the POR actually softened the XPS on the very thin trailing edge so a section had to be replaced.  

 

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The nose section was built in the same manner as for the previous Hawkers as a half shell over the plan.

NoseOn1.JPG.5526a0b65a0a4b45fa8790c51571adc8.JPG

The black square is the fingered heat sink for the ESC. The canopy will be the battery hatch.

The big printed nose cone proved to be quite an issue. Whilst I can print a nice elliptical nose cone this can only be done from a circular base but with the Hunter the first former is itself elliptical and not quite a symmetrical one at that. ?

FormerAA.jpg.4bedf96ddeb3de04f1a696c22c469110.jpg

A 'vase' printed single wall cone is quite flexible so I judged if I could get the circular base perimeter to be exactly the same as the perimeter of the required ellipse I judged it would be possible to 'squeeze' the nose cone base into the required shape. Took a bit of trial and error to get it exactly right but it worked giving a nice elliptical nose cone with a smooth transition from an asymmetric ellipse base to a simple circular base ellipse towards its tip. ?

The prototype Hunter was initially painted the same very pale blue/green as the P1081 so the next job is to give the grey XPS a white under coat.

Edited by Simon Chaddock
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The Hunter in white.

WhiteCoat.JPG.2c60d2e795ac12510f1858b680c6d224.JPG

Just a very light brushed coat as the acrylic paint is quite heavy.

It is amazing how the first coat shows up every hole and imperfection! A light sand with 120 paper and a bit more lightweight filler but always remembering this is just a light weight "foamie". ?   

 

Edited by Simon Chaddock
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First coat of the pale blue/green paint.

1stBlue.JPG.ca21e5d21334f55df7244b8011c4d8e9.JPG

Under artificial light the camera make sit look rather paler than it really is.

A rough check of the CofG compared to the similar wing of the P1081 indicates the battery will have to go rather further forward than intended so it will have to slide into the nose a bit from the cockpit.

BattForward.JPG.288a7d911fcf789e20305cfd7fdc0ce8.JPG

I want to get the Lemon stab rx from the P1081 in there as well particularly for the maiden. Its all going to be a bit tight!  

 

Edited by Simon Chaddock
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Nearly there!

The Lemon rx squeezed in and connected up.

StabRx.JPG.8052719f168ec956af45d369345da8c1.JPG

Paint complete and 'not quite right' decals added.

Outside the camera gives a better rendition of the actual colour.

Decals.JPG.6c62c1b6f3a9fa6c3eec10d63854e9bb.JPG

The canopy is off simply because it is held down by magnets and the glue was not set hard enough to hold them in.

It will need another clear lacquer spay to get the finish anywhere near the gloss of the full size.

Last job is to check (twice!) that the stab function operates in the correct sense then it is down to the weather.

I have never built 4 planes so rapidly one after the other.

Now I have the problem of where to put them. ?   

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Simon, I really enjoy your threads, and also admire your building skills, because I only ever (generally) work with wood plus a bit of f/g here and there. It has been great watching these Hawker types coming together because I followed all of them when  when I was a sprog. Your stated problem (where to put them) is not a problem that will solve itself I am confident. However now the 1067 is complete, look on it as an opportunity to start on the contemporary Supermarine types...... please ? Break a leg, with the maiden ?

Edited by maurice northcott
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Just to complete the story it flies! Sorry no video yet.

As I suspected the 50 mm QX EDF uses more juice than the 55 mm AEOs but it has quite an adequate performance for a light weight foamy. The complete lack of dihedral is noticeable but as I hoped the stab rx certainly keeps the sensitivity in check.

The Hunter alongside its development predecessor, the P1081

1288306228_HunterP1081.JPG.4862a5f6cc8da5773a33067b08532dfa.JPG

It certainly shows how 'slim' the Hunter is in comparison.  

Its next flight will be videoed.   

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I promised a video for the next flight. Well here it is all 4 seconds of it! ?

https://www.youtube.com/watch?v=aiQfd0f9P6E

The motor cut out. I don't know if the controls were still working although I was too low for it to make any difference.

What it did show is that XPS does not crumple and absorb the impact like Depron does so the fuselage broke in half just behind the trailing edge. The duct inside actually snapped into 3 pieces. The shock of the impact also shattered parts of the skin as well as creating long cracks in the wing roots!

A short video of the damage.

https://www.youtube.com/watch?v=FNIwPEhWMiw

The first repair was to attempt to join the duct. The first break was a simple glue job but the second was deeper in the fuselage and would have to achieve as the foam skin was joined at the same time. A short duct sleeve was printed to go ever the joint. Took some fiddling to get it all to line up a make a good foam join all at the same time.

After two days with a complete 'new build' nose section it now looks like this.

Complete1.JPG.3d7cc94003246a1968024033b3dc86dd.JPG

Although the skin is being restored to something like its original strength there is a concern that the shock loads may have reduced how well the skin remains glued to the formers. Without the proper former support the skin will tend to buckle and bow when under compression. ?

After repairs will it safe to fly? 

  

  

Edited by Simon Chaddock
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