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Jan 07, 2011, 10:50 PM
Thermal Wrangler
DrFragnasty's Avatar
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wip nexor pro


WIP,

All ribs/ servo bay close-outs done ready for routing.

Note the 'dam" at the joiner box. This is filled with a light bog
mix when closing the mold. Incidence pins are positioned just prior to
the bog going in. The 4mm pin holes are formed using K&S 4mm plastic dowel.

Next-up, routing top and bottom halves, slots for servo leads then ready for joining.


Chris.
http://www.seat.org.au
Last edited by DrFragnasty; Jan 08, 2011 at 12:07 AM. Reason: more fibre
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Jan 11, 2011, 07:16 AM
Thermal Wrangler
DrFragnasty's Avatar
Thread OP

WIP Nexor Pro; internals routed


All ribs/ dams/ spars routed.

Next-up servo lead holes, carbon patches for servos, measure hinge location again then join the wing.
Jan 24, 2011, 06:41 AM
Thermal Wrangler
DrFragnasty's Avatar
Thread OP

Closer to joining


2 steps fwd 1 step back

The hinge line on the lower skin clashed with the upper skin sub-spar at the tip root-rib.

Just enough so there wasn't enough room for the wiper to clear the sub-spar.

Moved the hinge line 3mm closer to the TE after measuring 5 times.

Note to self: the Nexor Pro has a kinked hinge line, NOT STRAIGHT.

Somewhere in step 342 I assumed it was straight and marked it as such.

Not a biggie but put us back 1 day.

The red heat shrink seems like a good idea. After it's cured the servo lead access hole is cut from underneath and located within are the 4 leads. The heat shrink conforms to the cavity and prevents the bog from touching the leads.
The blue foam inserts at the tip join allow the servo connector to be housed. After the bog has cured, acetone on a screwdriver is used to remove the foam. The subsequent hole is just big enough to house a standard connector on the centre panel.

Should join the top/btm tomorrow!

Chris.
Last edited by DrFragnasty; Jan 24, 2011 at 06:48 AM.
Jan 24, 2011, 11:50 AM
Just fly it!
wyowindworks's Avatar
Looking good, Chris. I like the heat shrink tube idea.

Adam
Jan 25, 2011, 08:35 AM
Thermal Wrangler
DrFragnasty's Avatar
Thread OP

Manual Labour


Thanks Adam.

Steve, Bruce and myself re-checked the thicknesses and found the TE was too thick as were the tips. This was put-down to a slightly conservative router depth.

A lot more sanding and planing of the TE, spars and ribs and a trial fit mold closure with joiner boxes in place justified the extra effort.

Also the aileron close-outs and locator guides are done and the spar where the joiner boxes locate hadn't been cut yet. All sorted.

It's now ready to join. Should be popped open on the weekend.


Chris.
Jan 27, 2011, 07:33 AM
Thermal Wrangler
DrFragnasty's Avatar
Thread OP
Spent tonight joining mold halves with Bruce.

Mixed up LY3600 resin and West 403 (colloidal and microfibre)
for joining. Around 350g of resin/bog mix made-up probably leaving 300g in the layup

Freezer bags used to pipe the bog along TE, LE, spars, joiner boxes and aileron sock close-outs.

Took around 2 hrs including butternut snaps and cups of tea.

Chris.
Jan 27, 2011, 01:56 PM
Detail Freak
target's Avatar
Good, Chris.

I've been waiting a long time for you to finish my plane!

R,
target
Jan 27, 2011, 10:41 PM
Thermal Wrangler
DrFragnasty's Avatar
Thread OP
If the wing's under 2Kg it's yours ;0)

Chris.
Jan 28, 2011, 07:14 AM
Thermal Wrangler
DrFragnasty's Avatar
Thread OP

Please release me let me go...


Despite only 24hrs for the joining bog to cure and despite my reservations about insufficient wax (Bruce & Steve were confident it'd be OK) the wing released pretty much perfectly.

It took a few percussive taps with a chisel to separate one tip then gentle coaxing with mylar strips under the leading edge to fully release both sides.

The LE is spot-on, the TE is a tad thick near the tips. It won't be razor thin.

The paint is AOK but didn't hold too well on TE of the flaps. There's carbon showing along the edge.

In hindsight I'd use flouro orange given half-a-chance after seeing how Steve's Supra Pro looks in the air at 600ft.


As for weight, it might be around 1374g ;0)

A bit much, but for a balsa lay-up with a big spar it's not too bad.


Next up:
Trimming LE/TE, cutting tips off, hinges, wiper gap routing, cutting servo bays, servo connectors and centre panel bolt holes.

Chris.
Jan 28, 2011, 09:17 PM
Detail Freak
target's Avatar
Sweet!
Jan 28, 2011, 09:51 PM
Retired USAF
cynjon's Avatar
That looks awesome Chris! Nice job!
Jan 29, 2011, 03:12 AM
Thermal Wrangler
DrFragnasty's Avatar
Thread OP

I give it a 7 out of ten


Thanks T and Cynjon (how's your XPro going Cynjon?)

Spent this arvo sanding the LE & TE (after attacking the garden with a whipper snipper/ evicting pygmy clans/ wild boars etc. etc.)

The LE is pretty much spot-on, the TE not so. Certainly not razor thin where just upper and lower fabrics come together creating that knife edge. It's more of a bread knife TE. It's a result of the fabric not sitting flush with the mold when it's joined.

Furthermore there's 2 cavities on the LE about the size of a flea each but apart from that it's looking good.

The next one will use the same paint (2-pak epoxy) but I'll see if it comes in flouro orange. The paint worked well.

Note to self: the inner 3/4oz needs to go in first THEN routed out for the spar/ sub-spar (to avoid the awful crimping and folding creases).

Also the next one will use Rohacel 51g instead of balsa to save weight and make feathering edges easier.

Chris.
Jan 29, 2011, 09:40 AM
Registered User
Quote:
The LE is pretty much spot-on, the TE not so. Certainly not razor thin where just upper and lower fabrics come together creating that knife edge. It's more of a bread knife TE. It's a result of the fabric not sitting flush with the mold when it's joined.
Hi Chris, it looking great!

I'm about to attempt something similar, but much smaller scale, and I've been concerned about the trailing edge thickness and getting the mold right. Could you expand a little on the part about the fabric not sitting flush with the mold ? I'm not sure I follow. Did a little of the fabric move up into the mold flange, or above the mold flange to keep the mold from completely bottoming out ? Better yet, what's the fix ? Thanks!
Jan 29, 2011, 05:13 PM
Thermal Wrangler
DrFragnasty's Avatar
Thread OP

Chunky TE


Probably 3 things Soggy:

Using balsa made it difficult (not impossible) to get the skins to taper properly. More fastidious attention to that would help as would moving to Rohacel.

The inner layer of 3/4oz didn't sit down as flush as it could have under vacuum due to the spar/ sub-spar getting in the way.

Too much fabric overhang over the TE of the mold made the fabric buckle-up around the lip under vacuum. Just a matter of cutting (while it's wet-out) it flush with the edge of the mold.

Easy enought to address on the next lay-up though.

As for the paint lines, I'm impressed! All done with ordinary beige masking tape.


What are you molding?

Chris.
Jan 31, 2011, 01:44 AM
Registered User
Its looking good Chris,
but on the same hand it looks heavy.


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