Wing bagging final

Well with only a week to go before these wings take to the air , I can post the final steps in the completion of these foam cored , vacumn bagged wings.
The finishing and fitting out is very time consuming but worth getting right.



The exposed foam on the wing and control surface is sanded into a concave shape (Dremel sanding attachment) in the case of the wing a small groove it routed out to allow the aileron servo wiring to be run in . This wiring (heavy duty twisted) is then sealed with a thin strip of masking tape. I also fit a piece of ply into the control surface where the control horn bolts through.
I now make up a mix of epoxy and flox with a little cabosil and paint this into the hollow. Once cured it bonds the skins together and makes a hard surface for the silicon hindging.





In this photo the silicon bead is run in and scraped flat across the gap with a shaped stick, I use a blue sellotape masking tape that releases and does not leave a sticky residue on the painted surfaces.




In this photo the ailerons are shown top hindged and the flap bottom hindged and secured in position until the silicon cures.



The next job was to cut the servo bays , this was marked up and a little cut at a time as I did not wish to cut the carbon spars, fortunately all my measurements were spot on and the servo fits just before the carbon spars and shearweb, more luck than skill.
Hardwood blocks and screws hold the servo's in place,

So in just over 30 days this glider has been completed, currently I am setting up the flight modes and programming and will certainly post some pictures of its first flights at the Sungazer Slope event next weekend.
Cheers
Mike

Ken's Fox. He's getting it ready for the Sungazer Scale Weekend at Volksrust

I wonder what the pilots think of it.

Wing vacumn bagging

Hi There
There will be this and one more stage in the completion of these wings.
Basically the structure is complete and it is the wing finishing and control surfaces that need to be completed.

The wing tips are made with the correct dihedral when joined with some strips of glass cloth.

As seen in this photo the alutube are cut through and these tipswill now align perfectly. The tubes are sealed and the blue foam sqaushed in a little , a mix of micro-balloons and resin is used to fill these hollows and makes a hard end rib once cured.

The hollows have been filled , the whole wing water-papered with 360 grit and the final coat applied the results are very shiney and I am pleased.
The glider is starting to come together and these wings will be a big part of its performance.
Each wing weighs about 1850 grams and the aircraft all up weight should be between 7 and 8 kgs with an estimated wing loading of 60-70gr per dmsq quite acceptable.
Cheers
Mike

Andy's Ju 87.

An elegant Spitfire, Tim's I think

Francois' Mistral takes off on aerotow behind Stuart's tug

Wing Bagging part 5

We left off last time with the wing in the vacumn bag overnight, I had a very good seal on this new bag and my vacumn pump (controlled by an electric switch coupled with a car advance vacumn switch)cycling about every 6 to 8 mins , after an hour I checked the vacumn/compressor set up and it was running ice cold.




Next morning everything looked ok except that I had misaligned the bottom skin at the root, but only some carbon cloth was short, when scratch building models "re-engineering " is often required , in this case I dont believe strength will be compromised so It will be filled as will all the hollows, waterpapered down and the whole wing given a final spray of 2k.



The second wing has gone into the vacumn bag and its time to clean up and trim wing number one. I always use a slight overlap and the mylars can move slightly , so first of its time to cut the trailing edge to shape where I have plenty of overlap.
I mark using a permanent marker and a straight edge the line to cut, then I mask this line with masking tape , the line shows through, this is important otherwise the cutting blade can slip and veer off damaging the surface, with a new sharp blade you cut with a series of cuts. This has a carbon skin which is really tough , I broke a sweat cutting this edge .


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The leading edge was carefully trimmed back to the rounded section that was formed during the core preparation.



The wing now looks great but has a few blemishes and a black leading edge , some sanding , filling and when both wings are ready , final paint. "IMPORTANT MESSAGE"
Sand the leading edge with a block and not your hand and sand paper trying to make a rounded shape, last time I did that the paper snagged the carbon tows , lifting a splinter that went right through the middle of my finger and resulted in a trip to hospital for removal, this wasted a whole evening of building time and some money.



So the next post is the finishing of of the tips and cutting the control surfaces
the servo wiring and servo placement. The fuselage is also well underway and if anyone is interested in how that is being built I will do a build sequence on that
No one has asked what the heck I am building (its a bit of a secret)its going to have its maiden flight at the upcomming Sungazer Slope event at Volksrust.
Cheers For Now
Mike

Denis and Peter. I think they were giving first aid to Denis' arm Peter's Extra in the foreground.