Jet Provost Late Starter Build

[Peter Garsden]

I am a new PSSA Member and a very late starter to the build. Hope to be at the Fly In next week with my Vulcan and newly built Alpha Jet.

Have started the build. Done half of the wing, and some fuselage.

Just wanted to warn people not be as stupid as I was. I failed to realise that the fuselage halves are in 4 pieces per side not 2 as I thought. Realised this when too late. I was looking at the plan through baking paper and there are a lot of lines.

Didn't realise that there are two pieces to stick at the top of each half. Glued the triangular bits to the top then realised they were wrong, and had to slice them off again - right mess needing filler.

I think that Traplet could mark all parts like they do the ribs and the Battery Box so it is clear. I had to ring them up to check. They were very helpful.

If each fuselage bit said Fus on it or something it would be easier. Here is a photo.

[Phil Cooke]

Hi Peter,

Good to see you on here and to know your JP is well underway!!

You are not the first one to be caught out with the 2 small pieces required on the fuselage sides, so don't worry! I'm not sure why Traplet label some parts with numbers but not others, it certainly aids the wing build (for example) to have every part individually marked by the laser etch...

Anyway, keep reading the other blogs on here for tips and lessons learnt as you press forward with your build, there's lots of good stuff on this forum section now so many of the builds are approaching airframe completion.

Look forward to seeing you at the weekend, the Alpha Jet sounds intriguing - we don't see too many of them on the slope!?

[Peter Garsden]

I have uploaded two photos just to show you what I have been doing tonight and also to ilustrate what a state the above error has made of the fuselage side. I had to fill it and reinforce it with 1/16th balsa, as it started to split. When prising off the triangular longeron it gauged out some balsa

Edited By Pete B - Moderator on 13/04/2014 10:08:44

[Peter Garsden]

If you dont have a fuselage jig, order one now from SLEC. They are brilliant - specially for a difficult bending fuselage like this one. I wondered whether it was an avoidable luxury but not at all. It can be used to hold things as well as bending fuselages together.

I have used it for every model I have made - even the Alpha Jet which was fibreglass lost foam. It was great for lining up the anhedral tail plane which was very different.

That having been said, I had to use not only the jig but also cramps at the top of the fuselage to hold it all together. This looks like block scaffolding

[Peter Garsden]

Late nights and early mornings make Peter poor and not very wise - is that the saying - think not. This is really turning into a comedy of errors. I like to see it as a word to the wise in case anyone is behind me in the build - maybe?

I managed to snap F5 like a twig when offering it up for fitting. Traplet have made the grain such that if you bend the former at all as you do when putting the fuselage together it splits by the notch at the top as the photo shows. So I have had to reinforce it with some of the scrap 2mm ply - pain.

[Peter Garsden]

After blithering on about how brilliant my SLEC jig was, when I dissembled the fuselage I noticed that the spring of the sides was so great, despite wetting it for 5 minutes as suggested by Andy, that it had not joined successfully even thought I had mixed in some special Ripmax reinforcement powder for fibreglass. It makes the epoxy harder - called Xilica and is better than microballoons - very good for moldies. So have had to reclamp overnight.

See you all at the Orme tomorrow?

[Phil Cooke]

Yep, Ill be there, but will my JP? Still covering here!!

[Peter Garsden]

Dihedral Brace Idea

My solution to the dihedral brace problem is to add another 1/32" ply brace on the other side of the spar (Actually the plan was under my jig, and I guessed the position wrongly as in front of the spar rather than behind, so I thought, why not have two it will bind the spar together and support it).

Problem is that the front one has nothing to attach to because of the spar, so I have made 3 pieces of 3/32 infill to glue the brace to - see picture

[Peter Garsden]

This is the photo of the two braces which are not bedded down yet or ready to glue but by way of illustration

[Peter Garsden]

Just before I go flying, thought I would show you the magic bottles of powder I bought to beef up epoxy. One is Xilica - it really does speed up setting so 30 mins turns into 5 and also hardens up the joint. I have bought it to glue to my fibreglass fuselage which does not take to standard epoxy at all - breaks away. it works. When I joined up my JP fuselage the glue was going off, and as such it hasn't stuck and has come away - so it has a down side.

The other bottle is milled fibreglass which I have not tried yet but fulfiills the same purpose.

[Peter Garsden]

Just thought I would post progress - behind all you lot. Have now nearly finished the wings. I have put in some Savox micro metal geared digital servos I got reduced price on Ebay SH0263 - nearly 9g. I do like Savox.

Even though I shortened the metal arms for the aileros to 20mm as recommended by Andy they still come out of the sides ever so slightly.

Error No 5 - arms for ailerons are not in line - not a major problem

Amendment - I used beech 3/16 x 1/16 for the aileron trailing edge - they neeeded it as the balsa I used is very soft. I also put a 1/64th plywood cap on the outside edge of the ailerons - makes it more robust.

In the photo is also shown my Proxxon Multi Sander which is just brilliant for the trailing edges - don't know how I did without one. Also my chisel balsa knife which I use a lot

I am now starting to think I will actually finish by 1st June.

[Peter Garsden]

[Phil Cooke]

Looking good Pete - still plenty of time to get this one finished!

[Mark Kettle 1]

Good progress Peter I think you'll make it, I'm only just back from holiday and only just started looking at the plan etc. Today may make a start on the ancillary parts like torque rods and elevator arms.

[Peter Garsden]

I got my torque rods all ready from Elite products via Blackburn Model Supplies - easy - nice lot of folks there too.

I have to say I wish my building was as neat as other people on this site but hey how - once I get over 70 maybe scale patience will kick in!

[Peter Garsden]

Tonight I inserted the 6mm dowel into the front of the wing. It was a very sloppy fit so I thought I would use Gorilla Glue. If you have not tried it, it is strong stuff, as the name implies. It start life as an orange goo, then reacts in the air to expand into a yellow hard resin foam. It fills gaps as it dries and reacts with moisture in the air.

The photos show what happen if you put in too much. At this stage, however it is still of glue consistency, and wipes away. It dries in 2 hours and can be sanded. I use it quite a lot.

Edited By Peter Garsden on 28/04/2014 22:56:10

Edited By Peter Garsden on 28/04/2014 23:01:00

Edited By Peter Garsden on 28/04/2014 23:02:17

Edited By Peter Garsden on 28/04/2014 23:07:22

[Peter Garsden]

Put in two of the same photo and cant work out how to delete damn thing

 

Edited By Peter Garsden on 28/04/2014 23:00:09

[Mark Kettle 1]

Well your moving it along Peter, that extra foam will cut and sand off.

[Peter Garsden]

You're right Mark. It has sanded down treat thanks to my Proxxon handy sanding multi tool. That thing is just brilliant. Reallly accurate and avoids the need for the recommended method of using masking tape. Here is a link nline&ei=fftfU4mEPcmFOPKzgEg&ved=0CE0Q2SswAQ">http://www.google.co.uk/shopping/product/7757069663392529335?sclient=tablet-gws&q=proxxon+delta+sander&oq=proxxon+delta+sander&pbx=1&bav=on.2,or.r_cp.&bvm=bv.65397613,d.d2k,pv.xjs.s.en_US.Cf9mlb6I5DA.O&biw=1280&bih=800&tch=1&ech=1&psi=6fpfU86lHcGi0QXI4oHgAg.1398799091573.7&prds=hsecnline&ei=fftfU4mEPcmFOPKzgEg&ved=0CE0Q2SswAQ

[Peter Garsden]

Why is it that most people show their best bits and I upload my mistakes? Because I am umble Mr Uriah Heep sir.

Secondly, sorry for using the slang testicle word. The moderator told me someone had complained and removed it.

I have departed from the advised PVA bandage method and used carbon tape, and resin - because I use it all the time to repair mouldies and to make my fibreglass Alpha Jet and I had some.

I also reinforced the trailing edge with some carbon tow - my fault for sanding it too thin, but was concerned about it being too fragile.

I know everyone is desperate to build light, but I found a Paul Janssen plan of the JP which is made of fibreglass and foam - it is not a floater which answers the point I suppose. The jets would have been easier in fiberglasss than balsa.

[Peter Garsden]

Also I am a bit concerned that one has to cut off one of the fuselage formers to make way for the canopy 1/16 base. Am I mistaken? I have studied the plan and it seems right. I took a cardboard template to draw the line. When I studied the photos some people seem to have stopped at F2.

[Mark Kettle 1]

The 1/16" cockpit floor base finishes at the front between F3 & F2 - I was checking out the size of and scale of the pilot head/s in cockpit

[Phil Cooke]

Pete - as shown in Marks photo of the plan above you have to cut down from F4 and ahead of F3, but not as far as F2. I didn't take a photo of it until I had lined it with 1/16th balsa but you can see here there is a length of fuselage top sheeting before you get to F2 (visible in this shot as I hadn't yet added the nose block sheeting ahead of it! Cutting the former is a little awkward once it is built into the fuselage, a Dremel is useful here to cut without applying too much load to the structure, its a little unconventional - but it does all work out!

[Peter Garsden]

Sorry, Mark and Phil for confusing you both - typo - I didn't mean F2, I meant F3. You can see in my photo that I have taken a balsa saw to it already in preparation for cutting it down. I have sawn it off - it made a good cut without putting too much stress on the structure.

Also because of the direction of the grain, I have decided to wait until I have carved down the fuselage to shape before applying the 1/16 sheet to line the canopy base - I figure it will be easier as the grain runs across the fuselage which willl make carving it difficult.

[Peter Garsden]

Having read about how Phil had had problems wiith the thickness of the walls of the jet at the back, I decided to make a cardboard template as I was unable to use carbon paper for the top of the tailplane.

So far the walls look thick enough. so I don't think I will need to use the wife's Liz Earle - not planed the rest of the fuselage yet so maybe.it will be OK or maybe I will need filler. Actually the tail may end up too heavy.