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Jet Provost 1.5metre Andy Blackburn PSS Plan


Peter Garsden
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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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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

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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.

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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.

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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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This is the JPEG of the version I amended.

jetprovostcockpitlayout(2019).jpg

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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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

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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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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

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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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Posted by Peter Garsden on 25/10/2019 12:00:13:

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

Hiya Pete - yep Im still working the plug, I've just been so busy with work I've not had much modelling time this week - I'll send you another update later today as I have a good days session ahead.

Gut feel is I should have the plug with Steve Davis at Vortex some time next week. Steve will no doubt pull a form and then make a production plug from that first form in his own material, so a little more work needed his end before we can offer the production product. Shouldn't delay you too long I hope!!

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Posted by Andy Blackburn on 25/10/2019 19:50:35:
Posted by Peter Garsden on 23/10/2019 20:13:47:

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

OK, no problem - if you could maybe weigh the covered parts without the radio, that would be great. I can make allowances for the covering (Oracover, I assume?)

 

Just weighed it at 65.8oz or 4ilbs 9 oz. Here is a picture so you can tell how much solarlilm there is. There are 2 servos in the wings but no servo or battery in the fuselage. Will now look up the surface area of the wing to work out the wing loading - it is 3.8 square feet which is 17.8oz per square foot - bit more to take account of the rest of the solarfilm and the battery.

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Edited By Peter Garsden on 27/10/2019 19:08:39

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Posted by Peter Garsden on 27/10/2019 19:00:19:
Posted by Andy Blackburn on 25/10/2019 19:50:35:
Posted by Peter Garsden on 23/10/2019 20:13:47:

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

OK, no problem - if you could maybe weigh the covered parts without the radio, that would be great. I can make allowances for the covering (Oracover, I assume?)

Just weighed it at 65.8oz or 4ilbs 9 oz. Here is a picture so you can tell how much solarlilm there is. There are 2 servos in the wings but no servo or battery in the fuselage. Will now look up the surface area of the wing to work out the wing loading - it is 3.8 square feet which is 17.8oz per square foot - bit more to take account of the rest of the solarfilm and the battery.

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Edited By Peter Garsden on 27/10/2019 19:08:39

That's looking pretty good - it's only just over 4lb so let's call the final weight about 4.5 lb, maybe 4.75 lb with a bit of nose weight, so even though it's about 60" span I'd say you're probably looking at 19-20 oz/sq ft.

Perfect! smiley

A.

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Posted by Andy Meade on 28/10/2019 15:29:08:

Cracking on with this one Pete! Let me know when / if you still want seats and pilots yes

Oh - what a shame, wish I had asked earlier rather than ordering from Real Model Pilots - not inexpensive at £69 per pilot on his seat. I am now kicking myself very hard indeed.

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