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Jet Provost 1.5metre Andy Blackburn PSS Plan

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Peter Garsden11/10/2019 15:19:14
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I have taken advice, listened to it, and followed it. Here is an extra piece of 1/8 ply on the underside of the wing not seen which will encourage the plastic bolt to snap instead of pulling out the bottom of the fuselage at least that is the theory. This is an addition to the plan.

Bob Jennings 111/10/2019 15:30:39
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Good move. Keep at it Pete, this is really useful and interesting.

Cheers

Andy Blackburn11/10/2019 18:53:32
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If the ply plate is fixed to the wing, then if one wingtip hits first and the wing bolt snaps, the wing will pivot in the horizontal plane and the ply reinforcement will remove part of the wing seat on its way out.

What you could do to try and manage this is to add a chamfer to the edge of the ply plate to try and persuade the wing to move downwards as well as sideways during the crash.

Edited By Andy Blackburn on 11/10/2019 18:54:32

Peter Garsden13/10/2019 18:29:17
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OK will do Andy - chamfering next job. I will use my handy Proxxon mini sander - great tool.

Anyway - following on from Andy' advice on his blog, I have used carbon tows and cyano to bind the wires together instead of fuse wire - works really well, but the brass tube I bought is too small so will swop it for a bigger size.

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Peter Garsden13/10/2019 18:39:21
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Have also been busy making decals from the very helpful photos sent to me by the Newcastle shared Jet Provost that I am copying based at Durham Airport - **LINK**. I emailed them and they were incredibly helpful. They have photographed all the decals close up for me. They also offered me a flight if I pay for the fuel. Couldn't be more obliging. They are also going to take a photo of hte cockpit for me.

I used my Vinyl Cutter to not only cut letters using their software but also print and cut on white vinyl. Worked reasonably well. I uploaded the images then put it through my printer then cut out the scrap. I had to do this for the airforce logos as they were to intricate to cut with a scalpel. The square ones I will simply score with a knife on white printable vinyl with a sticky backing, then the third sheet is clear sticky printable, which will show up against a white background of the top of the fuselage and the grey wing.

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Some of the images I made with Adobe Fireworks - the stripey no step stickers on the right as I couldn't find an internet image. The black squares showing the fuel inlets I made with Microsoft Word

Edited By Peter Garsden on 13/10/2019 18:42:56

Peter Garsden13/10/2019 21:20:34
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1607 forum posts
1187 photos

Next job is to cut out the cockpit profile. As I am going for a deeper cockpit I might put in some extra reinforcement, I don't know. I will definitely put in a floor. The question is what i do with F3 because it will have to be cut out . I think I can cut it right down and it won't affect the strength that much. I plan to cut it out and create a new former where the cockpit starts and the fascia sticks. We will see

I made a cardboard cockpit outline as you can see

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God bless cardboard

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Peter Garsden14/10/2019 21:07:17
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1187 photos

Next job is the tricky under wing sheeting, which is made from 2 sheets of 3/4 inch sheet. I actually ran out of 3/4, so the second sheet was 2 pieces of 3/8" laminated together.

The wing seat ply reinforcement, the wing bolt the dihedral of the wing, and the wing reinforcing tape all stand proud. and the wood needs to be recessed to fit round them.

Andy's helpful tip is to rub a 4B pencil lead on the edges then rub the wood over them to make marks. to cut round

I now need to use epoxy to fix them in position.

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You can see that I have lined the under wing seating with cling film to stop the excess epoxy from sticking the wing to the fuselage.

Edited By Peter Garsden on 14/10/2019 21:09:41

Peter Garsden17/10/2019 15:19:45
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1607 forum posts
1187 photos

This shows the fairing after pairing down with a David Plane and Permagrit files. Due to the raised hight by the bolt head it ended up very thin. A gap also appeared by the trailing edge join which I have filled with P38.

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Notice the judicious use of masking tape to stop the plane taking off unwanted chunks from the fuselage.

Peter Garsden17/10/2019 15:21:17
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1607 forum posts
1187 photos

Next the under wing air intake extensions, which I have carved from 3/4 balsa. Tricky. I used the same sand paper rubbing method to line up the intakes with the fuselage fairing

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Peter Garsden17/10/2019 21:22:53
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1607 forum posts
1187 photos

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Blocks all carved to shape ready for covering before being glued on - would be a filming nightmare with compound curves to negotiate otherwise.

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Looks like a chap wot 'asn't been tut dentist tha' knows wi' 'is teeth all spikey?

Not very neat but they are just there for support of the upper surface - won't be seen as they will be covered by the underneath sheeting.

Peter Garsden18/10/2019 21:08:18
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1607 forum posts
1187 photos

Made some progress with the cockpit. I have used the Dremmel to cut out F3 down to the top of the battery box and have used some 2mm cut offs from the wings to create a cockpit floor.

I have also found a better fascia, which is missing 2 bits but is better IMHO than the version we used for the smaller one. Will upload and post the version I have edited with Fireworks in case you want to use it.

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Peter Garsden18/10/2019 21:30:36
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1607 forum posts
1187 photos

This is the JPEG of the version I amended.

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Previously I have printed out the image on photographic paper, but it is thick and leaves a white edge. After buying some matt printable vinyl, I uploaded it and printed it out then cut it out - perfect. Cut out the image then stuck it onto some 2mm balsa then cut out the edge - perfect.

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Peter Garsden22/10/2019 21:04:47
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1607 forum posts
1187 photos

Andy and Phil put wing fairings on their JP's and I didn't, so, to make it look more authentic, and to help aerodynamics I should do so. I have followed Andy's blog

First I made a paper template, and cut out 2 bases from 1/64" ply, rebated the wing seat by .5mm and glued it them in position

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Peter Garsden23/10/2019 07:54:19
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1607 forum posts
1187 photos

Tricky bit are the fairings. Andy suggests in his blog that because they are so small, soft balsa block is probably the best. In this bigger version, I think that 1/64" ply is better with a combination of thin and medium cyano to fix it in position as it has to bend quite a lot.

Paper templates are the order of the day - particularly the rear template which bends in 3 planes to account for the curve of the fuselage bottom sheeting

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I think that an intermediate former is called for to form the correct curve.

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This shows the rear bottom piece which measured about 30mm for each side of the triangle (not the hypotenuse) with 2mm recessed into the fuselage (I used a Dremmel disc to cut the slot)

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Paper template for the front

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Place it on the sheet and draw round it - you can cut the 1/64 ply with scissors which makes it a lot easier with the curves.

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Paper template for the rear top piece - I marked the edges with my nail then cut it out - do a separate one for each side as, if you are anything like me each side will not be sanded identically.

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And both pieces in situ with some filler to await drying and filing/sanding

Edited By Peter Garsden on 23/10/2019 07:56:08

Peter Garsden23/10/2019 07:59:15
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1607 forum posts
1187 photos

I lined up the wing, fin and tailplane then pinned the rear top fuselage side pieces into position. It will help line everything up, but covering this will not be easy. Separate pieces for each curve and tailplane sides will be necessary, as otherwise the film will pull away from the join in that it is concave.

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Andy Blackburn23/10/2019 08:24:35
509 forum posts
487 photos
1 articles

Looking good, impressed with the dashboard.

Any chance you could weigh all the structural bits before you start covering, please...?

A.

Peter Garsden23/10/2019 20:13:47
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1607 forum posts
1187 photos

Sorry Andy - have now covered the wing. I can weigh everything though if you wish?

Peter Garsden23/10/2019 20:13:49
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1607 forum posts
1187 photos

Sorry Andy - have now covered the wing. I can weigh everything though if you wish?

Peter Garsden25/10/2019 12:00:13
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1607 forum posts
1187 photos

Little nudge for the canopy Phil - where are we up to with it?

So to the fin. As you can see from the picture it is made up of 3 colours with a logo in the middle which I have all ready, so how to lay out the colours. I made a template by drawing round the fin, then marked the lines for each colour, then marked the pattern on the reverse of the film so it only appears on the clear backing film with a Sharpie as usual.

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This is a picture of what I am building, printed out and pinned up in the workroom.

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I cut the white slightly oversize so it could tuck under the red and the blue - the red is slightly see through and shows up dark colours underneath - as I discovered with the Canberra. You can see that I put the red and blue templates over the top to line it up.

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White in place

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Red and blue on - note bare balsa left at the gluing points

Edited By Peter Garsden on 25/10/2019 12:02:23

Peter Garsden25/10/2019 12:16:54
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1607 forum posts
1187 photos

I have made yet more decals - these are for the top of the fuselage and on the jet intake. I made it in Adobe Fireworks with lines etc - took ages as I couldn't find an image online then uploaded it as a cut image to my Vinyl Printing Program - Cricut's own.

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The lights I took from one of the photos the nice chaps from Durham Provost Community took for me, screen shotted it, took out the surround and flipped it for a left light - I only had a right one, again in FIreworks, and have made it into a print then cut vinyl image. Really getting into this now

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