Finally we have reached the stage where we can launch and test fly our prototype!
If you look closely you'll see the blunted end of the Jart with the unforgivable prop fixed to the front! Vic being a purist was much distressed but agreed to come to the field and watch Daron do his thing.

Daron : the elected test pilot

I canabalised my hotliner, (composite Baudis Zoom) and removed the Axi motor and planetary gearbox. We knew the arangement would work as both planes have a similar all up flying weight of 1300g and fitted a 14x10 folding prop on a 28mm spinner. The nose had to be reshaped from it's oval profile to accommodate the spinner.

The actual launch was pretty uneventful except for a twitchy left and right wiggle as Daron adjusted his fingers on the controls. The motor arangement can take the plane up vertically and by the time Daron cut back the throttle back, the Jart was a tiny speck in the sky.

That was when the problems began......

Daron failed to level out before cutting back and the plane entered a stall and seemed to drop a wing. Besides being so high up our colour scheme did not help with the oriontation and the plane never recovered from the spin. Hard to believe with all that height to play with. We have come to the conclusion that it was all pilot error!

The plane hit the ground nose first on a hard surface. Th amazing thing is that there is hardly anything wrong with the plane. The motor gearbox, prop and elevator servo are buggered, but for the rest the plane is still intact with marginal damage to the wings and fuse.

It was rather distressing, but we'll try again! Just waiting for parts.

Vic's pulling his nose at the thought of a prop!

At this stage the going has not been to good with two flights and two crashes. The first was Vic's balsa prototype in a 100km/h wind and Daron's disoriontation....

Third time lucky!

Johann, Daron & Vic

Finally some progress!
When you receive e-mails stating " I keep looking on the JART-SA blog hoping to see someones Jart progress but nada, niks, and zero." you know the pressure is mounting.
Well to recap, we shaped and glassed plug number 2. There was some debate as to the finishing coats and unfortunately we applied some epoxy coating that ended in disaster. The full curing time was 10 days which conveniently fell over the Christmas holidays.

Plug number 2

Epoxy coating gone wrong

Gel coat and epoxy coating in a marriage gone wrong

Not quite the best spray booth.

Dejavoux

Plug set in the splitter board

The plug still stuck in the mould, but salvaged

De lamination of the K2, probably due to the adhesion to the

epoxy finishing coat remaining in places after sanding.

And finally! The mould had to be cleaned off, but

came out beautifully

4mm studs used as locating lugs

Layup complete and curing

Bench flying!!!!

The fuse seam joints have been a bit of a headache. On this one we tried a wet joint as we have been to scared to cut the mould to enable us to work on the seams. whilst the joint is sound, the overlaps have folded in places.

On the following fuse, we will try smaller overlaps and two pairs of hands!

Thanks for all the continued advice and support.

Finishing for first class results

Hi There,

With Johann currently tackling his second attempt at a moldable plug I thought I would post some pictures of my method , which is by no means the only way of doing things, but works for me.

Although 2k paint sometimes sticks in the molding of the plug , this is most likely due to problems with the release agent and not the paint. B.T.W. this type of paint 2k has been very successfully used in all the team built Shongololo's of Evans building groups, and is still my favorite when spraying a plug and polishing it, or the mold surfaces of a hollow molded glider.

After the blue foam plug is nicely sanded to shape and layed up ,with in this case 3 x 163 gr cloth layers, I sand it smooth with 180grit paper, especially glass cloth join lines.

Then the whole plug is layed up with a layer of 104 or 86gram fine cloth, I add a small amount of micro balloons to this resin layup , this aids in filling pinholes. You will see that although the foam is blue the resin/balloons make it look whiteish.

The plug is now wet sanded with 220grit , the surface becomes smoother and any imperfections are filled and repaired.

The product shown left is an epoxy based finishing resin , it is a two part and seals the surface well and is easy to sand.

Its available in most good hobby shops.

I make a mix of this and add microballoons , this finishing layer is screeded onto the plug and gives a high build smooth coat , as you can see, this is then waterpapered with 480 grit wet and a few drops of dishwashing liquid in the water.

This surface seals the foam from any solvents and provides a good surface onto which you can spray.

My larger plugs were finished in a similar way

but instead of the ZAP finishing resin I finish with a 2 part polyester spray filler (but care is needed as this stuff eats the foam , if it's exposed.)

I trust this may be of help to modellers out there.

Note 2K paint contains ISOCYANATE (a Cyanide derivative) in the harderner which is bad for you, so always wear a respirator and protective clothing.

Happy building.

Thanks for all the support and guidance especially from Evan and Mike. It seems like this has turned into a bit of a process....
I have not had a chance to respond to your e-mails, but I'll get there!
Evan, we managed to get the coating that you recommended for the plug. We tried several places and between only selling the paint in 5l tins at R1600.00 we finally managed to get a litre. I hope it is the correct one! the trade name is SIGMAGUARD HS which is described as a two component high solids polyamine cured epoxy coating and comes in a green grey colour.
The curing times seem to be a bit of an issue as it is described as 20 hours min between coats and 10 days for final cure.....
That means we will only cast our moulds in January......
Vic has given up on us and has proceeded to build a fuse out of balsa. (He has the time and it's his preferred building technique anyway) It may be a blessing in disguise as we can use the prototype to iron out all the gremlins. We'll post some pictures as he progresses.

Meanwhile Daron and I can dream about our future composite plane and colour schemes whilst we wait!


Mmmmm Daron likes black and yellow....

Hi there Mike, Evan & Vic

Thanks for the support that you have provided so far. I must say that some things you mentioned are so logical that I can't believe we never thought it thru such as casting the otherside of the mould without removing the Plug.


Plug number 2


Anyway, The new plug has been shaped and layered up with one 50g cloth and one 200g layer. We have re sanded and got back to shape with minor blemishes.
Should we put on another layer of glass, as I noticed the previous plug developed small pressure indentations during the final sanding and polishing phase?

Our wings are progressing well with some help from Vic Oxley who is an old hand at constructing built up wings. He has kindly undertaken to construct the wings for us. We would love to try bagging, but without a vacuum pump and the suitable knowledge, we will leave this process in abeyance for the time being.
Vic has been building and flying in our area for the last thirty years or so!


Vic Oxley hard at work in his workshop


The foam cores have been cut and he has elected to build a balsa covered wing which poses a bit of head scratching as regards the fixing of the wing to the body.

The thought has been to cut the"canopy" opening down to the bottom edge below the wing so that the wing can be bolted down to the lower section of the fuse and the enlarged canopy will be shaped to the top of the wing profile. It may help to have a removable wing and we are looking to put a centrally placed servo for the ailerons....
We're getting ahead of ourselves!

Thanks for all your positive comments and support.
Kind regards
Johann & Daron

Johann & Daron

It all starts somewhere......
It was about messing around on the Internet, browsing to see what planes were around, when we happened to come across the Jart web site. After looking around the local builders and seeing Adrian's build thread it made us believe we too could build this plane..... how hard could it be?
The fact that neither of us had built a scratch plane (balsa or glass), other than damage repair, did not deter us.
We sourced some Iso board and shaped the plug... so far so good
Then read up on all the epoxy and paint coating specs.....
glassed and painted....
( not without mishaps)
And we were the proud parents of a Plug!!!!
All shiny and smooth.
This was then laid up as described by Evan and others

My daughters got so exited when they saw their Dad busy with blue paint that they volunteered to help....

This only lasted for 5 minutes until they discovered that it was all gooey and did not come off.

The splitter board came off with no problem.

And......

It STUCK.....

I'm trying to get over it!

I must admit it's hard not to just give up.

I'll give it a day or so to come to terms with my short comings...

I suppose it's part of the learning curve and life's rich tapestry of experience.

We'll post some more pictues of our next build....

Progress - down the twisty road now!!

Wings out of the bag, root ribs had to be ditched as I forgot about trimming to the fuselage angle before adding the ribs....

I used a rubber polising wheel on the dremel to dig out the foam. You can go right up against the skin without damaging it and it eats up the foam no problem.

Then I mixed a strong cotton flock mixture (with no cabosil to allow it to run) and

poured it in the gap. The leading edge was dug out to about 50mm to seat the alignment peg - a 5mm diameter length of music wire fitted with an alignment tool - just an old printed circuit board with two holes drilled through it.

A bit of paint, some articulation and a new twf pnf toy is born!!

Articulation

Side on -

Full turn!

Look Ma, no elevator- no aileron ................ no Brakes!!

Just two servo's to fit (DS8711's with plenty amandla) and a ledge for the canopy and were are done.

ps - anyone else done a twf Jart in SA?