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Semroc - Swift BG

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msjohnso

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I realize I am jumping in late here, but my un-brother Kevin is right. Weight is your enemy. My typical glider finishing consists of the following:

- Work up the wing and tail surfaces to the desired shape, dressing them down to smoothness with finer sandpaper, down to at least 400 grit. If the airfoil is hand-formed, get all the lumps and bumps out at this stage.

- Apply two coats of clear dope, cut 50% with dope thinner, to both sides of each surface. On raw balsa, it dries really quickly and you will be able to do both coats in a matter of minutes. You want to do both sides at the same time, and prop the pieces up on edge, because doing one side at a time can cause warpage. Often I don't even use a brush - a soft cloth or even Kleenex tissues works quite well.

- Let these parts dry overnight or thereabouts.

- Lightly sand with 400, then 600 grit sandpaper, to reach a high degree of general smoothness. Don't worry about the grain, you'll take care of it with the next step.

- Now here comes the tricky part. Cut out pieces of Japanese tissue and apply them to each surface, shiny side out. Make the tissue pieces with a margin about 1/4 to 1/2 inch on all sides. The tissue can be obtained at many hobby shops that cater to free-flight model aircraft folks, or online at peck-polymers.com. You'll use the same 50-50 cut dope both as an adhesive and a cover coat. Typically, I will start at the leading edge of a surface, applying dope in bands a half inch to one inch all the way across the span, then apply the tissue, stretch out the wrinkles and work out the air bubbles, and then move on to the next section, holding the tissue folded back until the next area has been doped.

- After you have finished an entire surface and have the wrinkles and bubbles out - I work them with kleenex - apply a light coat of dope to the whole side and wipe most of it off, sort of like applying stain to fine woodwork. Then apply the tissue to the other side of the same part immediately, in the same manner. As with applying the base coat, this is needed to keep the part from warping.

- When the flat surfaces are dry, trim back the edges and seal them down in a reasonably-aerodynamic fashion, again using the 50-50 clear dope.

- Let all the wing and tail pieces dry thoroughly (overnight should be enough), then lightly sand with 600 grit sandpaper and proceed to assemble the glider.

Many folks may differ with me, but on 3 and 4-panel dihedral wings, I generally cover an entire wing half as a single piece, then cut and bevel for the wing dihedral. I will admit that it takes time to learn how to do tissue well, but it adds a lot of strength and darn little weight. There is a distinction between "Japanese" and "American" tissue - the Japanese imported stuff is a little bit lighter - but both are available in several colors. Being red-green color blind, I use a two-tone scheme on my B/G wings a lot of the time - red or orange on the bottom, for contrast against the sky, and blue for the top, since it contrasts well against brown weeds or dirt, as well as most hues of green grass.

MJ
 

AKPilot

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If for competition yes. If for enjoyment no.

The problem for recreation is that people leave on too much primer. If most of it's sanded off, and the paint applied appropriately (e.g. not saturated) you'll be okay. Often the aerodynamics/lift of the wing can more than adequately compensate for an ounce or two of paint; if not increase lift, due to a decreased amount of parasite drag.
 

JAL3

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Oh noes! I fear the glider will turn into a brick! How much weight did the filler and kilz add? I know you aren't going for competition like performance, but extra weight is your enemy with gliders.

kj
I didn't weight it before I sprayed on the Kilz. I tried to keep it light.

If it has a glide ration better than 1:1 when this is done, I'll be well satisfied.

Weight has long been my enemy. A few years ago, I was much heavier than now, 492 lbs. The doctor said, "John, yer average NFL cheerleader ways about a hundred pounds, not including the silicone. You could stand to lose 2 and a half, mebbe three cheerleaders.":eek:

Now I've been losing cheerleaders all my life. Its something I'm good at. I figured I'd go ahead and give it a try.

I'll make sure I sand off at least a cheerleader's worth of KilZ.
 

JAL3

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I realize I am jumping in late here, but my un-brother Kevin is right. Weight is your enemy. My typical glider finishing consists of the following:

- Work up the wing and tail surfaces to the desired shape, dressing them down to smoothness with finer sandpaper, down to at least 400 grit. If the airfoil is hand-formed, get all the lumps and bumps out at this stage.

- Apply two coats of clear dope, cut 50% with dope thinner, to both sides of each surface. On raw balsa, it dries really quickly and you will be able to do both coats in a matter of minutes. You want to do both sides at the same time, and prop the pieces up on edge, because doing one side at a time can cause warpage. Often I don't even use a brush - a soft cloth or even Kleenex tissues works quite well.

- Let these parts dry overnight or thereabouts.

- Lightly sand with 400, then 600 grit sandpaper, to reach a high degree of general smoothness. Don't worry about the grain, you'll take care of it with the next step.

- Now here comes the tricky part. Cut out pieces of Japanese tissue and apply them to each surface, shiny side out. Make the tissue pieces with a margin about 1/4 to 1/2 inch on all sides. The tissue can be obtained at many hobby shops that cater to free-flight model aircraft folks, or online at peck-polymers.com. You'll use the same 50-50 cut dope both as an adhesive and a cover coat. Typically, I will start at the leading edge of a surface, applying dope in bands a half inch to one inch all the way across the span, then apply the tissue, stretch out the wrinkles and work out the air bubbles, and then move on to the next section, holding the tissue folded back until the next area has been doped.

- After you have finished an entire surface and have the wrinkles and bubbles out - I work them with kleenex - apply a light coat of dope to the whole side and wipe most of it off, sort of like applying stain to fine woodwork. Then apply the tissue to the other side of the same part immediately, in the same manner. As with applying the base coat, this is needed to keep the part from warping.

- When the flat surfaces are dry, trim back the edges and seal them down in a reasonably-aerodynamic fashion, again using the 50-50 clear dope.

- Let all the wing and tail pieces dry thoroughly (overnight should be enough), then lightly sand with 600 grit sandpaper and proceed to assemble the glider.

Many folks may differ with me, but on 3 and 4-panel dihedral wings, I generally cover an entire wing half as a single piece, then cut and bevel for the wing dihedral. I will admit that it takes time to learn how to do tissue well, but it adds a lot of strength and darn little weight. There is a distinction between "Japanese" and "American" tissue - the Japanese imported stuff is a little bit lighter - but both are available in several colors. Being red-green color blind, I use a two-tone scheme on my B/G wings a lot of the time - red or orange on the bottom, for contrast against the sky, and blue for the top, since it contrasts well against brown weeds or dirt, as well as most hues of green grass.

MJ
I appreciate the tips. I AM going to keep them handy for if I ever want to try a competition glider. I know I will someday and when I do, the process you describe sounds like an enjoyable challenge. Right now, though, it seems like WORK!

Of course, a lot of the things I do with rockets now that are enjoyable sounded like work when I first found about them. And it was...but I grew into it. I'll grow into the gliding too.

Thanks again for the tips. I do appreciate them.
 

JAL3

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If for competition yes. If for enjoyment no.

The problem for recreation is that people leave on too much primer. If most of it's sanded off, and the paint applied appropriately (e.g. not saturated) you'll be okay. Often the aerodynamics/lift of the wing can more than adequately compensate for an ounce or two of paint; if not increase lift, due to a decreased amount of parasite drag.
I'm not at all confident that the lift generated by my wing section is something to be proud of, except that I think its the best I've done to date. I'm pleased.

I am curious to see in a few days how the paint and primer will affect the glide. I hope it still glides. I'm feeling lucky right now and think it will. If not, it will look reasonably good as it plays the Stuka.:D
 

JAL3

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A day later, the pod was sanded again. I was mindful of the warnings I had heard about building up too much sealer/primer/paint and went after it with 320 and then 400 sandpaper. When I was done, I had misgivings because it mostly still looked white. I could see grain and pencil marks, though. Knowing how fast Kilz covers things up, I figured that most of what I was seeing was the chalkiness of the balsa fillercoat.

SBG-primer-sanded-1.jpg


SBG-primer-sanded-2.jpg
 

JAL3

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The pod was then taken back to the booth and given a single coat of gloss white.

SBG-white-1.jpg


SBG-white-2.jpg
 

JAL3

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The glider was sanded with similar results. There were still some nasty spots of grain but I sanded down to where the wood was just starting to show through.

SBG-primer-sanded-3.jpg


SBG-primer-sanded-4.jpg
 

JAL3

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The glider was then given a single coat of gloss white as well.

SBG-white-3.jpg


SBG-white-4.jpg
 

AKPilot

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John, your builds are a personal inspiration to me. :)
 

kjohnson

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Tip for next time, mask off the part of the pod that slides into the glider. If that isn't a loose fit, your pod may not come off which will ruin your day.

My guide for this is if I hold the glider, will the pod fall out of the slot with no shaking or tapping, then it should be good to go. If there is any resistance, I sand the hook, slot or both.

kj

A day later, the pod was sanded again. I was mindful of the warnings I had heard about building up too much sealer/primer/paint and went after it with 320 and then 400 sandpaper. When I was done, I had misgivings because it mostly still looked white. I could see grain and pencil marks, though. Knowing how fast Kilz covers things up, I figured that most of what I was seeing was the chalkiness of the balsa fillercoat.
 

JAL3

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Tip for next time, mask off the part of the pod that slides into the glider. If that isn't a loose fit, your pod may not come off which will ruin your day.

My guide for this is if I hold the glider, will the pod fall out of the slot with no shaking or tapping, then it should be good to go. If there is any resistance, I sand the hook, slot or both.

kj
Thanks.

I'll check that out.
 

JAL3

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The next day, a ring of masking was applied just below the nose cone of the pod and foil was wrapped around the rest of the body.

SBG-masked-for-orange-1.jpg
 

JAL3

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The nose cone was then sprayed a bright orange.

SBG-orange-1.jpg


SBG-orange-2.jpg
 

JAL3

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The glider was masked as well leaving the wing tips, boom and vertical tail assembly exposed for paint.

SBG-masked-for-orange-2.jpg


SBG-masked-for-orange-3.jpg


SBG-masked-for-orange-4.jpg
 

JAL3

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The glider then had its date with the orange paint. This was done in 2 stages so that I would have something to grip.

SBG-orange-3.jpg


SBG-orange-4.jpg


SBG-orange-5.jpg


SBG-orange-6.jpg
 

JAL3

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The next day I peeled off the masking to take a look and It was looking good.

SBG-orange-7.jpg


SBG-orange-8.jpg


SBG-orange-9.jpg


SBG-orange-10.jpg
 

JAL3

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That left only the blue striping and I took out the tape to mask for a thin stripe on each wing and the the horizontal stabilizer. I then used a brush to place the blue paint.

SBG-masked-for-blue-1.jpg


SBG-masked-for-blue-2.jpg


SBG-masked-for-blue-3.jpg


SBG-masked-for-blue-4.jpg
 
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JAL3

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So far this project had gone extremely well; better than I had imagined it could with a glider project. Now was the time for tragedy to strike. It struck when I removed the masking and saw what had happened when the paint had wicked under the tape.

SBG-blue-1.jpg


SBG-blue-2.jpg


SBG-blue-3.jpg


SBG-blue-4.jpg


SBG-blue-5.jpg
 

JAL3

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While I was stewing about the blue paint, I took the time to test fit the pod to the glider. It was a bit tight due to paint having gotten in the hook cavity. I took a sanding stick and cleaned it out some until the fit seemed a good one.

SBG-pot-test-fit-1.jpg
 

TheAviator

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So far this project had gone extremely well; better than I had imagined it could with a glider project. Now was the time for tragedy to strike. It struck when I removed the masking and saw what had happened when the paint had wicked under the tape.
You said you brushed on the blue paint? I think that's pretty much your problem. By brushing on the paint, you put far more paint on than would be applied with good spray technique. After I started doing mist coats instead of heavy coats of paint, my problems with bleeding pretty much disappeared. For small projects like this, you may want to try purchasing an airbrush. It is particularly handy with gliders because the paint flow rate is controlled to a much greater degree.
 

e42

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John, Another great build. Sorry about the paint bleed. I look forward to hearing about the maiden flight.


--- Ron
 

JAL3

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You said you brushed on the blue paint? I think that's pretty much your problem. By brushing on the paint, you put far more paint on than would be applied with good spray technique. After I started doing mist coats instead of heavy coats of paint, my problems with bleeding pretty much disappeared. For small projects like this, you may want to try purchasing an airbrush. It is particularly handy with gliders because the paint flow rate is controlled to a much greater degree.
I appreciate the tip.

I do have an airbrush around here someplace. I've used it exactly once and that was several years ago.

I think the main issue here was my own laziness. I tried to get by with simple masking instead of doing it right. That coupled with the grain not being fully filled let the paint seep under the tape. You're right that there was certainly more present than if I had just sprayed.

Live and learn.:cool:
 

JAL3

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John, Another great build. Sorry about the paint bleed. I look forward to hearing about the maiden flight.


--- Ron
Thanks for the support. I hope it will take off 2 weeks from today.:D
 

JAL3

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A day later, I was sure the blue paint had dried completely. I took some white acrylic and used a brush to try and cover up the worst of the bleeding. It certainly toned things down but it could probably stand another 2 applications in addition to the 2 that were put on.

SBG-white-touch-up-1.jpg


SBG-white-touch-up-2.jpg
 

JAL3

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The decals for the Swift are a simple matter but add a lot to the finished product. The largest of the decals has the Semroc logo and the name of the rocket. I mounted it as on the facecard; on the dorsal surface of the right wing.

SBG-decal-1.jpg
 

JAL3

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The kit also came with a pair of smaller versions of the same design. These were mounted on the horizontal stabilizer, one on top and one on the bottom, both on the right as you face the rocket.

SBG-decal-2.jpg


SBG-decal-3.jpg
 

JAL3

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My kit also came with an additional decal identifying is as production number 10 and having some more info about the rocket. I put this one on the left dorsal surface of the main wing.

SBG-decal-4.jpg
 

JAL3

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That completed the "finishing" and, as I said, I thought even the simple decals added a lot.

SBG-done-1.jpg


SBG-done-2.jpg
 
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