GliderIreland - Ireland RC Forum - Flying Model forum in Ireland
Gliders => Slope Soaring => Topic started by: billscottni on September 24, 2009, 20:41:31 PM
-
Most people will know of the Jart, but for those who don't check out;
http://www.jartworld.com/
Plans used to be free, but now are $10. I've had mine for a looooong time and only just getting round to building. The Jart is available to buy in a couple of versions, but being a tight Scotsman, I'm going to build from scratch. Model has a glass fuz which I'm going to produce using the lost foam method. The best explanation I've seen of this can be found here: http://www.pjmodelclassics.be/ under Building Methods. Basically you shape the fuz in foam, glass over that and then melt out/remove the foam. The wing will be a standard vac bagged blue foam. The original is a one piece, but I'm going to make the wing removable for ease of transport.
Started tonight, by making templates for the fuz,
(http://www.gliderireland.net/forum/images/uploads/billscottni/DSC00002.JPG)
I then cut this from blue foam and shaped it before starting to cover it in strapping tape:
(http://www.gliderireland.net/forum/images/uploads/billscottni/DSC00005.JPG)
More to follow as it gets done
-
Hi Bill
Please, please, please, please sir! can I have one of these.
JohnP
-
Make yourself the fuz and I'll get the wings and tails done for you!
-
Looking forward to this build Bill. I got a Jart LT. Like you, I got the plan off Reed ages ago but never got round to it.
Those just cardboard templates? Cut with a hot wire?
I built a 2 metre U2 from a PJ plan. Lost foam fuse. Good quick way of making a decent fuse. Plan on doing another few in the near future. Have a few more PJ plans that need building.
-
Hardboard templates! It was what was lying around the garage! Seal the edges with cyano or epoxy, but it does burn if you don't keep the wire moving.
Yes Hot wire cut and the lots of sanding.....bloody blue dust gets everywhere.
Cut off the vertical fin to shape it using SD8020 templates and will stick it back in place before I glass it.
Prnter has packed in, so I will have to wait until monday to print wing and tail templates for the cut
-
O.K. Bill
Thats a deal, I will call with you this week some evening, I have to call into Ian's to finish the Elan.
JohnP
-
Hi Bill
Just on the BMFA website, and seen this Jart for sale at £250, not cheap
http://www.bmfaclassifieds.co.uk/detail.php?id=5013
JohnP
-
Half the appeal of this model when it first came out, was the fact that it HAD to be built from scratch. That's still the appeal for me.
Although you can buy them now, thy're still not available in huge numbers.
-
Joe,
I take it PJ is Paul Lanssens?
What's your next build from his plans?
-
Yeah, meant Paul Janssens.
I've had a few of his plans knockin' about for a while now. I will go for either a 1.5m Seafury. Which will be a decent size with chunky fuse. Or a 1metre Mirage 2000. The Seafury is foam veneer wing and fuse. The Mirage is a lost foam fuse and a built up wing. Both have been scaled up from the original plans.
The original 0.72metre version
(http://www.gliderireland.net/forum/images/uploads/joe/mirage2000_nieuw.JPG.jpeg)
Original 1.12metre version
(http://www.gliderireland.net/forum/images/uploads/joe/pic%20paul2.JPG.jpeg)
-
I'd go for the Seafury, but then I like prop jobs.
-
Suscribed to that one ! :D
Not finished yet !!?? :P
-
Not yet. Printer's playing up so can't print out templates for the wing.
-
Some movement on this build.
Joe very kindly offered to cut me a set of wings using his cnc cutter. These arrived today and are far better than I could have done with templates and my drop arm cuttter.
I have attached the vertical fin to the fuz and tomorrow will finish fairing it in to the main fuz. Then I'll be abe to apply the carbon, kevlar and glass.
Will add pics as I go through the stages
-
Fin attached to plug and ready for fairing in. Then I'll get the glass and carbon on it before melting out the foam. Put a couple of balsa ribs in the fin for strength.
(http://www.gliderireland.net/forum/images/uploads/billscottni/jart%20fin.jpg)
-
Will you do all the glass/carbon at once or one layer at a time?
Had my Jart LT out a few days ago down by the sea. Lots of wind. Haven't flown it in decent lift for a long time. Really good. The best flights I've had with it. It really suits the smooth coastal lift. Well, I guess thats what it was designed for after all. Unfortunately only got half an hour in before the wind showed up.
Just some encouragement for you Bill.
I'm sure your fuse will be solid Bill. The LT version is like an egg shell. Rotor slammed me into the ground twice and I have a nice big crack to show for it. The gel coat is very brittle and the layup is very light for this sort of machine. Will try get some carbon in there one of these days. That pointy nose is not the easiest to get into though!
-
Probably a layer of glass, then carbon followed by at least 1 more layer of glass. Carbon will be in the high stress areas e.g. wing seat, base of fin.
Usually don't do them all at once, which means they have to be lightly sanded before the next layer goes on
-
doing it all at once it a PITA. Don't ask me how I know. Might be a little lighter that way but you probably get a better smoother job with one layer at a time.
-
Looks great Bill. But just one question. How do you make sure that the fin is straight on the plug.
-
the good old mk 1 eyeball, checked from in front and above!!
nothing fancy Alan.
-
One of my New Years resolutions, apart from losing weight (Doctors orders!), is to get my ass in gear on the builds I have on the boards.
Ordered some bits I need for both the KA-3 and the SU25, (mainly brass tube, piano wire and carbon tube/rod).
Then I got on with glassing the lost foam fuselage. Attached is a pic of the fuz with the first layer of light glass added. Tomorrow I will put on some carbon reinforcement, (around the wing mount and LE of the fin).
(http://www.gliderireland.net/forum/images/uploads/billscottni/jartglassed.jpg)
-
Hi Bill. Good to see the jart back on the building board. What weight and how many layers are you going for?
-
Not aiming for any particular weight Joe. More concerned with durability.
That first layer is a light cloth (50g/m), easier to work with on the smooth tape surface. I'm then planning on a length of 50mm carbon tape along the bottom from nose to tail and layer of the same tape on the LE of the fin. Possibly a criss cross pattern of Carbon tow nose to tail to give an overall strength. Then at least 2 layers (maybe 3) of a heavier cloth (100g/m), finishing off with another layer of the 50g/m.
That's the current plan, but I will adjust if the strength doesn't seem too good. Hope to get the carbon and one layer of 100g/m done tomorrow and then cut tails for it.
-
Not as much done as I'd hoped today. :?
Got the carbon reinforcement along the bottom of the fuz and LE of the fin done. Carbon reinforcing and another layer of glass (100g/m) on the hatch, which doubles as a wing cover too. (see the second pic in my first post).
Sanding down of the first layer of glass took longer than anticipated and I was a lazy bugger and had a lie in!! :!:
-
As I said in my Fiu thread, a productive weekend. Spent today sanding the final layer of "heavy" cloth in the Jart fuz. Resorting to the angle grinder on a couple of stubborn spots to remove epoxy runs. Carbon tape aling the bottom and fin LE. Carbon tow reinforcement in a couple of strategic places. One layer of "light" cloth now needed to finish it off before a final sanding and shooting primer/filler on it.
(http://www.gliderireland.net/forum/images/uploads/billscottni/Jart%20fuz%20glass.jpg)
-
You've gone building mad Bill!!
-
Ex-wife pissed me around over seeing the kids, so I needed to do something to get it out of my system :!: :!: