HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Aug 15, 2007, 08:53 PM
Embrace the suck
nauga's Avatar
Joined Nov 2004
4,269 Posts
Discussion
YAJBT (Yet another Jart build thread)

Jeff Charlot, I’m Rick James and I thought a long time ago that three or more people building Jarts together should be a lot faster than building the same number independently. Turns out we were waaay wrong, but have a good story to tell anyway. The idea was that each of us would do what we were best at, and if there was something none of us knew we’d learn it together. I learned a lot doing it this way, and I’ve already had a chance to apply what I learned on other airplanes. It took a lot longer than I think any of us expected, but considering how different our build styles (and levels of shop cleanliness/organization – I’m at the bottom of that one) are I’d say it went amazingly smooth. On with the show.

Nauga,
who needs a time machine
nauga is offline Find More Posts by nauga
Last edited by nauga; Aug 16, 2007 at 12:58 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 15, 2007, 08:55 PM
Embrace the suck
nauga's Avatar
Joined Nov 2004
4,269 Posts
We started with Reed’s blessing and two blocks of S2S basswood crosscut roughly to fuselage length. A couple of passes with a red rattle can will give a defined centerline when the planks are face-joined. They were glued up with PU and clamped for a while. The PU makes shaping the blank a *lot* easier than epoxy or pretty much any other shop glue.

Nauga,
with PU on the face
nauga is offline Find More Posts by nauga
Reply With Quote
Old Aug 15, 2007, 09:01 PM
Embrace the suck
nauga's Avatar
Joined Nov 2004
4,269 Posts
The fuselage profile was traced onto the bass blank, then roughed out on a bandsaw and edges smoothed with a bench sander. Things happen quickly on a bench sander with clean belts. We start to see the PNF shape come through.

Nauga,
who has no fingerprints
nauga is offline Find More Posts by nauga
Reply With Quote
Old Aug 15, 2007, 09:08 PM
find me @samotage
samotage's Avatar
Melbourne Australia
Joined Jul 2005
8,362 Posts
mmm, this must be the progenator for that unbenownst Jart run featured some time ago?

Sam,
and his eye for the detail.
samotage is offline Find More Posts by samotage
Reply With Quote
Old Aug 15, 2007, 09:09 PM
Embrace the suck
nauga's Avatar
Joined Nov 2004
4,269 Posts
The canopy/hatch was cut on a bandsaw and a good seal made with Bondo Ultimate and wax paper. The hatch was then screwed back onto the fuse for final shaping.

Nauga,
racing the dinnerbell
nauga is offline Find More Posts by nauga
Reply With Quote
Old Aug 15, 2007, 09:16 PM
Embrace the suck
nauga's Avatar
Joined Nov 2004
4,269 Posts
The vertical was laid out on poplar (why? Because it was handy.) and trimmed. After shaping the LE and TE it was glued to the fuse blank and faired in with scrap wood and Bondo. Once we were all happy with the shape the hatch was pulled, the screw holes filled with body putty, and the whole thing was given many coats of WBPU and sanded and sanded and sanded…

Nauga,
tired of paperwork
nauga is offline Find More Posts by nauga
Last edited by nauga; Aug 15, 2007 at 10:17 PM.
Reply With Quote
Old Aug 15, 2007, 09:18 PM
Russ Young
isoarthenland's Avatar
United States, UT, South Jordan
Joined Mar 2006
1,168 Posts
Oh boy...more moldy stuff
isoarthenland is offline Find More Posts by isoarthenland
Reply With Quote
Old Aug 15, 2007, 09:34 PM
PNF
infopimp's Avatar
Los Gatos, CA
Joined May 2005
4,422 Posts
PNFscribed.
infopimp is offline Find More Posts by infopimp
Reply With Quote
Old Aug 15, 2007, 09:54 PM
Embrace the suck
nauga's Avatar
Joined Nov 2004
4,269 Posts
'Precision-cut' CNC cores were next. We started with Foamular 250 because that’s what was hanging in the rafters…that would soon change. And finally one night we had a bench-flying session with the plug. We tried cutting stab cores but decided later that they weren’t up to our standards. A glance at the stab core setup should tell you that that was bound to happen.

Nauga,
teetering on the brink
nauga is offline Find More Posts by nauga
Reply With Quote
Old Aug 15, 2007, 10:04 PM
Embrace the suck
nauga's Avatar
Joined Nov 2004
4,269 Posts
The canopy got a little rework before laying up the canopy mold. Finally, the fuse was masked and the canopy plug waxed, then the mold was laid up with the plug in place.

Nauga,
who saw this part through pictures
nauga is offline Find More Posts by nauga
Reply With Quote
Old Aug 15, 2007, 10:05 PM
Embrace the suck
nauga's Avatar
Joined Nov 2004
4,269 Posts
I'm Rick James and Jeff Charlot layed up the mold - If you can get me some pics I'll add them here so they're in order. Like magic the fuselages started appearing.

Nauga,
following orders
nauga is offline Find More Posts by nauga
Last edited by nauga; Aug 16, 2007 at 12:27 AM.
Reply With Quote
Old Aug 15, 2007, 11:35 PM
Insert custom witicism
Jeff Charlot's Avatar
San Diego
Joined Jun 2001
3,526 Posts
Sean may have a few good pics of the mold making process. Then again.....he may not. It was a fun night, learned a lot and ended up with a Jart mold! After that, the fuses just started falling out of the mold, as if by magic. Pffft!
Jeff Charlot is offline Find More Posts by Jeff Charlot
Reply With Quote
Old Aug 16, 2007, 12:33 AM
Embrace the suck
nauga's Avatar
Joined Nov 2004
4,269 Posts
At some point we decided to abandon the foam horizontals. We cut balsa tail skins and sandwiched carbon fiber and Kevlar hinges, then glassed and bagged them.

Nauga,
and his continuity check
nauga is offline Find More Posts by nauga
Reply With Quote
Old Aug 16, 2007, 12:36 AM
Retired USAF
cynjon's Avatar
USA, SD, Piedmont
Joined Jul 2005
2,910 Posts
Very nice Nauga/IRJ/Jeff! I would love to learn how to do fuse layups and make my own Jart some day...I guess we need to start a Kansas build club.

Subscribed...
cynjon is offline Find More Posts by cynjon
Reply With Quote
Old Aug 16, 2007, 12:41 AM
Embrace the suck
nauga's Avatar
Joined Nov 2004
4,269 Posts
Through a communication mixup the pink foam wing cores ended up out of our hands for a while, so we decided to cut new cores rather than waiting until we could get the originals back (by the way, I have since retrieved the originals and still have them. They are available if anyone is interested). We sheeted them with 0.8mm door skin ply and epoxy. I was amazed when Jeff showed me how little epoxy is required when bagging the skins – there’s that learning thing again. These wings are sooo much lighter than any others I’d done previously with epoxy…and just as stiff. Since it was bare wood on top they were bagged with just peel ply and breather around the skins/cores and into the bag – no mylars (yet).

Nauga,
who is done for the night
nauga is offline Find More Posts by nauga
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Build Log Oh yeah another jart build Thread! W49 Slope 48 Oct 18, 2006 08:46 AM
Discussion Yet Another Raptor Build Thread A6INTRUDER Slope 22 Apr 07, 2006 10:49 PM
Yet another what to buy thread... (SAL/DLG, long post) dimple Hand Launch 28 Dec 20, 2003 04:36 AM
Yet Another Brushless Switchback Thread 02ViperTwin Parkflyers 89 Oct 22, 2002 03:07 PM
Yet Another Zero Build Question Runyond Parkflyers 1 Jul 21, 2002 03:19 PM