dhal22

ooops! more photos.

david

MTK

Vacuum bagging is a simple and extremely effective way to do many things in this hobby, including sheeting foam. For all of you who still build models, it's a worthwhile technique to learn. I place only the sheeted wings in the bag, not the whole assembly. Once vacuum is applied, the bag is placed on the husk and left there to cure. The outcome is as accurate as the cut foam was to begin with. Compression is extremely consistent throughout so there's very little chance for warps to develop.

MattK

dhal22

matt, i believe you, just never got around to building a vacuum device.

david

MTK

David, you need a small vacuum pump, a nylon bag (ACP carries and 18" and a 30"; I use the 30" and fit both panels at the same time), a pair of vacuum seals (ACP again), a vacuum gauge installed on the pump's suction and a bleeder valve to control the amount of vacuum the pump draws. Oh yeah, plumbers putty to seal around the suction tube where it enters the bag. Paper towels provide the vacuum path through out the bag

MattK

Atlanta 60

My Feedback: (18)

Just so happens I know where you can get a Really Good Deal on such an apparatus...

You would need a regulator for skinning wings but that wouldn't be a problem...I've only used for making parts so it's set up for 100% debulk...I was going to get a regulator for doing wings but havn't got around to it yet...

Have Fun...

Chuck

dhal22

send me some details chuck. thx.

david

dhal22

filling in the retract areas using 1/64 birch ply and balsa. also exposed the aileron servo pockets. i plan on using a couple of aileron servo panels from an arf that expired long ago. just goes to show you there are uses for arfs.[X(] soon to have a full wing. i can't wait.

david

rghalcomb

Hey Dave your gear opening looks good. Keep it up..........Ron

dhal22

what a great hobby!

david

MTK

Dave,

Hopefully you reinforced the bottom skins adequately before you skinned. That many cut outs on the bottom of the wing could be a strength problem. I am talking from experience and on the one that failed on me, the skins were 3/32" and the wing was fully glassed. I admit to some fairly snappy snap rolls doing the wing in so if you don't fly crazy you may be ok, but better safe than sorry.

One way to get strength back at the cutouts is to lay down a layer of 1-1 1/2 oz cloth first and then glass with the 0.6 oz cloth. Or altrenately, a layer of 0.5 carbon mat then glassing as usual

MattK

dhal22

thx, any lightweight strength advice is always welcome. anyone else have a foam wing failure because of retract/servo cutouts? i did not use any spars or carbon strips under the skins.

thx, david

dhal22

Mattk, i used Probond polyurethane to glue the skins to the foam. an extremely strong method as the expanding glue injects itself into the foam and wood. i don't know what method you used on your failed wing but the poly glue method is a heck of a lot stronger than the 3M adhesive spray method i used in the 90's. i think i've got a pretty strong wing here. please no offense taken here at all.

david

Deadstik

My Feedback: (8)

David,

I wouldn't worry too much about your wing as the method you used is very strong. I've never had a wing fail due to retract or servo cutouts and I too like those SNAPS......

Plane is looking great David....


Dan
Carolina Custom Aircraft

MTK

Used epoxy, vacuum bagged. It's never been a problem before but on that fateful wing, well, it cracked the bottom sheeting through the cutouts, both sides. It surpised me actually. I used 3/32" 5 pound density balsa. The wing did not fail fully; just cracked the bottom sheeting.

The pundits will say it will never happen. My point is it can and it will given the chance. You may never have a problem but you might, and it might ruin your day. Up to you.

Since going to conventional gear set-ups and plug in wings, the issue has never re-appeared. But then again, loading is lower and construction technique has improved from 20 years ago. The tube socket is installed using 1/8" thick 15" long balsa subspars top and bottom along the length of the socket (spanwise) and the sheeting is glued flush on the subspars. Very light and strong and highly recommended method for those wing types.

Not a help for the Angel tho since it's 1 piece wing.

BTW, 1-piece wings can be built easily with sockets and can be pull apart twin panels if one desired such a set-up. Just as light as the glassed center section types and with the added convenience of pull apart features for easier transport.

If there's interest, I can outline the technique I developed around the time we transitioned to plug in wings (20 years or so give or take)

MattK

dhal22

taking a break from wing work i decided to get the engine opening done. wasn't as bad as i thought.

david

dhal22

don't know why i go through long layoffs on my projects. i needed some thick wood for the wingtips (my order of balsa from national balsa has been disappointing) so that was part of the downtime. i ended up laminating the wingtips and adding a 1/8 lite ply center section for dent resistance. being too aggressive on lightening holes caused me to build a 2nd set of wingtips. more shaping is still to be done but i'm getting there. i also decided to try to line my engine opening with 1/64 birch ply. it should neaten up the opening once i get to the glass and paint stage.

dhal22

edit

dhal22

i'm starting to get behind on updates. since there are other places to get step by step construction tips i will skip to a couple of recent photos. i have shaped the ailerons (8178 style), finished the wingtips (except for final sanding), completed the wing mounting to the fuse and i am getting close to having the belly pan shaped.

hrrcflyer

Hey David,

You don't want to know what us loyal thread followers do to people who get behind with their updates......[>:]

At the rate you're going, you will be ready for paint in no time. Keep up the good work[sm=thumbs_up.gif]

dhal22

i should finish the belly pan later today and then what? rear stabs need to be attached and then i really am getting close to glass time. more later.

zubba

Man is that looking sweet!!
"line my engine opening with 1/64 birch ply" I am going to have to steal that idea , that cleans up the opening perfectly.
Awesome build !!!

-Jason

dhal22

since it worked so well i'm thinking about doing the same thing with my nose gear retract opening. there is a lot of blue filler in the photos (i don't build as tight as some do), it is evercoat rage lightweight body filler. it's ready to sand in 3-5 minutes and very easy to sand. i like to use the regular balsa colored filler also but it takes a lot longer to dry. of course the color won't matter after fiberglass and paint.

dhal22

more belly pan work. it is all filled in and ready for final sanding. i painted a coat of watered down hobbylite over the balsa not covered by evercoat. it makes for a super smooth finish after sanding. i did the fuse that way and was very happy with the results. i will 'paint' the balance of the wing that way next.

pitstop000

My Feedback: (26)

Nice work there Daid,
Realy like the engine bay, A finished edge like that when painted will look realy great ( like a fiberglass fuse)
I'm also going to get some of that evercoat stuff, How is on weight?

dhal22

seems to be very light. i've heard superfil is lighter but the evercoat was available right down the street.