K8 recovering

[blake]

Tom,

Perfect, I will do the same thing, thanks for the great drawing.

Starting the port wing tonight rebuild tonight. When I have stuff drying there I will attack the fuse fairing.

Blake

[blake]

I found this on Tom Bodes ASK18 build, I will do something similar for the K8 but not with the removable gap cover.

[blake]

Ok,

After working on the port wing last night I found some time to look at the root area. I removed the one top piece of balsa that forms the main contour and found that there are several formers in this area that will need to be either removed entirely or reworked.


The area in question. If you look at the yellow and red bird in a previous post, you can see that this is not representative of the full scale KA8 at all.
So with direction and advice from Tom P, I proceeded to open up this area and see what was in there.

Some gentle prying and some muscle and up she came! The pencil line represents the more scale like outline for the sheeting like Tom showed in his drawing.

The areas under the filler are solid blocks of wood and will have to be removed to enable the rework of this area.



This is the look I am going for in my rebuild. You can see the definite line of the separate panels, which is totally different from what the model has right now in this area.

Hopefully tonight I can get some more work done on this project...

Blake

[Tom]

Hmmmmmm.....I would remove all of that framing thats there and start from ground "zero" so to speak.....put some sticks from root to root to support the new balsa skin and then frame in the canopy shroud on top of that. All of that framing that's visible is non structural......so it can all go away.

[blake]

Ok,

I got onto the centre fairing rework and I think it came out looking pretty good.

First step was removing all of the old formers that were in there creating the odd shape.



Next was adding the new cross braces to support the sheeting.



After that dried I added the new sheeting.



Then I created an new sub former behind the existing canopy bow.



After that, I glued in the new centre sheeting that conforms to the actual airfoil shape. The extreme outboard ends of the new sheeting made it possible to use hardly any filler at all in this challenging area.



Another view from the side showing the new lines.



Just some final sanding and then it will be time to glass the entire forward fuse.
I came up with a little rolling stand rig that makes working on the fuselage very easy.



More to come...

Blake

[Tom]

Excellent job!

[ARUP]

Nice! Looks much better.

[blake]

Thanks guys!

Tom, if you do the same thing to your 8, I would suggest you use thin plywood instead of the balsa like I did. To get it to conform I had to sand it pretty thin in spots and its pretty delicate at the moment. I'm glassing the entire front of my fuselage so I'm not too worried about it though.....just a thought.

Up next, I have to re- hinge all of the control surfaces as I had to cut the hinges to separate the components so I could strip the all the old covering off. I bought one of those "Slot Machines" to do the job, hope it works? Anyone here ever used one of theses things?




The saga continues.....

Blake

[lenb]

Yup,
They're pretty good. Practice on a scrap a time or two and see how you like it. Makes short work of the job once you get the hang of it.

[blake]

Thanks Len. I will try it out tonight on some scraps before I try it out on the actual airplane.

[ingrahal]

Start your slots with a hobby knife to give the slot cutter something to follow. Keeps it from wandering at the start.

[lenb]

Good idea Art

[ingrahal]

Thanks, blind hog finds the acorn!!!

[blake]

Ok guys,

Getting inline with the title of this thread I actually started covering the airframe last night.
Spent about 2.5 hours out in the shop just doing my thing....a wonderful experience!

Started with the largest parts, inner panels, both top and bottom, and with the offcuts I managed to get the lower surface of tips covered as well.

My first time using Solartex, love it, great stuff!




Inner panels done, both upper and lower surfaces.









Tips only have the lower surfaces done so far. Managed to use the offcuts from the inner panel layouts so very little wasted material so far.

The work continues!

Blake

[ARUP]

Oh boy! You get a great feeling when the covering goes on the model! Looks really good!

[blake]

Thanks Michael,

Managed to get out to the shop again last night for a bit more covering.

I did the topsides of the tips and managed to use the offcut to cover one of the ailerons.

Questions for you experienced Solartex installers....what do you use to shrink it and at what temperature?

I shrunk the aileron using my covering iron and it seemed to work quite nicely, but I used my heat gun on the actual tip panel and it didn't seem to really pull up tightly enough. Mind you I didn't really throw the heat at it as I was being quite cautious. Any hints out there?

[lenb]

A wise man once told me " read the instructions, follow the instructions, love the instructions.

Covering has a very specific heat range. Scot ( Stew ) is a master at covering and explained to me if you put the covering on with the iron set only to activate the glue, then you will not distort the covering and get excess wrinkles. Once pulled tight and sealed down, step 2 is the first round of shrinking with a temp set as per instructions for that covering. USE AN IRON.
Step 3 is another round of tightening with the temp higher and still only use an Iron.

I was a heat gun guy too, but you cant control the heat with the gun, therefore going past the proper stretch point and the covering will relax in the sun and wrinkle.

Thats my 2 cents,

[blake]

Thanks Len, I will actually sit down and read the instructions before I do anymore covering...LOL!

[Stew2]

I'm no master, especially of my own domain.... wait wrong Seinfeld episode. They guy who taught me to cover was the master. He showed me how to cover 2/3 of a cue ball without a wrinkle and without it ever loosening. It is quite simple actually, the basic philosophy is that you stretch covering on, you don't shrink it on. I set the iron to just activate the adhesive, tack and stretch. You can pull out almost every wrinkle without even shrinking the covering. There are times when you do end up pulling up short lengths that were previously adhered, but that is ok, just get every last wrinkle you can by stretching. This means that you can't be afraid to leave a 2" margin of material all around the part because you need it to be a handle for stretching the covering. Once that you stretched the covering on, go back over it with the iron and your hand to make sure the covering is stuck to the wood surfaces. Then you can shrink the covering. For stuff like Ultrakote shrinking will level out the adhesive and layers of color underneath the mylar top layer and make the covering look like glass, IF you have smoothed and sanded the wood frame. I sand down to 400 and then clean the crap out of the framework with dry paper towels to remove all the sanding dust. Any dust will prohibit the covering from adhering to the framework. i.e. it sticks to the dust, not the framework.... For Solartex or 21st Century fabric, the same process is used and you will see that the shrinking process again, only flows out and evens the covering, it is not used to remove wrinkles. Any wrinkle you shrink out will relax to some degree in the sun and probably show its ugly head. I also prefer to cover in the late WInter when the humidity is lowest in my dungeon/shop and the frame is at its "smallest". Covering is actually easiest with 2 people, one to hold the part, one to stretch and iron. For covering, I always use an iron, just as LEn said, you simply can't control the temps with the heat gun. There is NOTHING that you can't heat with a gun that you can't heat with an iron. Use a sock on your iron to prevent scratches for the "plastic" covering and I use on for the cloth coverings as well, just to keep the iron clean. Very little pressure is used with the iron, it is the heat that is doing the job. Pressure just dents the wood and leaves drag marks. So, stretch your covering on and no pressure on the iron. Temps are all set by testing with pieces of covering to get the adhesive to activate, but not shrink, from there, you can use am iron thermometer to step up the temps to the shrinking temp defined in the destructions, but it is like color sanding paint, you want to go the least aggressively as necessary to get the job done, so use the lowest temp necessary to shrink/flow the covering, leaving the higher temps for the next guy to use.... Heavy curves, like wing tips and edge radii are done by using a temp that would shrink the covering, but you don't let the covering shrink, you heat it with it pulled tight and just off the curved surface, and stretch it over the curve. The tighter the curve, the smaller the amount of material you heat and stretch. I'll be honest, the hardest thing about covering is how to hold the piece you are covering so you can stretch the covering over it. If I am covering solo, I typically do it sitting on a stool so I can use my legs to hold the piece and my hands to stretch and iron. I have to admit, I have never watched the professional guys do it who have made videos, so if they contradict what I have here, then do what they do, they are the experts. This stuff is just what has worked for me. Hope it helps. Have fun!! Covering is typically a very rewarding process.