Saturday, December 20, 2014

FlisKits Mercury Redstone Build Part 9 Tower Step 3

Continue gluing on the horizontal pieces.
Hold them down with small pieces of tape.

The diagonal ends are cut to the correct angle, taped and glued in place.

All are still left long.

Run a razor blade under all the glued corners to free the glued ends and to make sure everything remains attached.

Secrets of Estes Modeling, Part 2

And more from the same article:

Now you can attach the fins. Here you do use Titebond. do not use epoxy. The Titebond will make a better bond here because you want the water in the glue to pull the resin into the wood of the fin and the paper of the tube. Sorry, but epoxies won't do this and contrary to popular belief among rocketeers, epoxy is the poorer of choices for attaching fins.

Apply a bead of Titebond along the root edge of a fin. Wet the end of your finger and rub along the corner edge of both sides of the fin to make a nice straight glue bead. Don't dilly dally. Carefully attach the fin to the tube between the alignment lines. Do your sighting to make sure it is straight.

Note how the fin bonds to the tube within a few seconds using this technique. You have to have it straight, guys, when you put it down. Now hurry and look from the rear of the tube to be sure the fin stands straight out. You have just enough time to tweak the fin alignment before it sets. This may sound as though this technique is tricky, but I can tell you once you use it you are going to really like it. It just works.

You need to learn from experience just how much glue to put on the fin edge. If you put too much then of course it is going to squish out when you put he fin down on the tube. That's okay as long as you get to it before it dries. I keep a damp Q-Tip at the ready to drag along the fin-body tube joint to clean it up. You DO need to add a small fillet to complete the fin attachment and you can get this at the same time you attach the fins if you have learned the correct amount of glue to put on the root edge. The fillets we want are where the fin-body tube joint is just 'blurred' by the fillet. Anything larger just doesn't look professional.

We pre-finish blow-molded nose cones by dragging a razor blade along the seams to clean even out the joint, sand the entire surface, putting on a coat of the gray primer, and sanding smooth with 400 to 600 wet or dry. At this point the entire model is in gray primer. If not, then make sure it is. The reason is that whatever base color you put on, it will look the same over the entire model. Now, sand everything again using the finest sandpaper you have and wipe it down. A tack-rag is okay as long as most of the goo is gone out of it. It's waxy by nature and if it gets on the model your paint will bead like water on a waxed car.

But wait, there's more. You make this next choice, but we like to put on a coat of flat white Krylon on the entire model followed by a nice even coat of gloss white Krylon. At this point the model is ready for whatever final finish it needs. Note here that the Estes R&D group uses Krylon almost exclusively for all models. We have just never found anything else that works as well over the last twenty years. We do use Pactra or Testors on injection molded plastic parts because Krylon attacks them. Every model you see in the Estes catalogs have been painted with Krylon almost exclusively. BUT you guys can use whatever you want as long as the models come out okay.

What do you know, Estes uses Q-tips too!
I've read a few forum posts where people recommend tack rags. I don't use them for the same reason Mr. Dorffler mentioned: It's waxy by nature and if it gets on the model your paint will bead like water on a waxed car." 
Personally, I like smooth fillets. The larger the model, the wider the radius of the fillet. Smaller models get Titebond M&TG, larger models get epoxy. I guess my fillets aren't very professional!
This article was written a few years back, before Krylon changed their paint formulas. Don't bother with the new Krylon spray paint!

Friday, December 19, 2014

Launch, Soccer Field, December 18, 2014

It was cold by the time I walked over to the Schoolyard field, arriving about 7:30 a.m.
Parachutes will need some dusting with talcum powder to open up.

The (Quest Cobalt) ORANGE was first up to check the system and check for any winds I couldn't feel on the ground.
The Quest A6-4 got it to about 275'.
The parachute is packed into the nose cone, 2/3rds of the NC shoulder base was removed to open it up. I pack the shock cord and Kevlar line in the nose cone first, then the parachute on top of that hoping that the shock cords will pull out the chute. Today it didn't.
It landed easily enough without it but one fin was broken off at the root edge, an easy fix.

The Quest X-15 with an Estes B6-4 is a good fit for this field.
Altitude was about 300' with full chute deploy.
I caught this one before it hit the ground.

I haven't flown the Dr. Zooch TITAN IIIC since June, 2013.
This was my best of the day with an Estes B6-4 reaching approximately 300'.

There was a full garbage bag parachute and another
catch before the flame fins hit the very short grass.

I almost launched the Quest VIPER with a Quest B6-4. This 25mm diameter model would have been lost on this small field.
I switched out the engine for an Estes A10-3t in a adapter.
This 13th flight got to 275' with no damage when I picked it up.

I'm always surprised by how high this stubby, flat nosed model flys.
This is the Custom NOMAD launched today with an Estes B6-4.
Altitude was around 325', an 12" Odd'l parachute brought it down easily.

On the left you can see the nose cone sitting above the body tube end. There's not much room inside and the parachute pushes up the nose cap.
Five up, five recovered. A good start to the day.

FlisKits Mercury Redstone Build Part 8 Tower Step 2

I bought some Evergreen styrene, .030" rods for the verticals and .020" rods for the horizontal an diagonal struts.
These are slightly larger than Mr. Flis recommends but I wanted the tower a bit stronger.

All the tower strut lines were extended beyond the drawing to make the angle cutting easier.

Wax paper was taped down over the tower plans.
The vertical rods were cut oversize and taped over their lines.

To cut the horizontal strut to the correct angle, it was set down on a copy of the tower immediately to the right.
The left side of the strut was cut at an angle to match the angle of the vertical piece.

Cutting all the struts to the correct angles gives you more glue contact.

The horizontal strut was glued down by transferring a very small amount on a toothpick tip.
Note the right side hasn't been cut yet.
All the right side ends will be cut when the tower side is finished. I'll be able to cut the three horizontals with one pass of a razor blade.

Thursday, December 18, 2014

FlisKits Mercury Redstone Build Part 7 Tower Step 1

I emailed Jim Flis about wanting to build the tower instead of using the card stock tower supplied in the kit.
He sent templates and a heavy card alignment stand for gluing it all together.

On the left are the drawings Jim Flis sent.
On the right are some drawings of the Redstone capsule and tower I already had.

The Flis supplied drawings give you the basic tower sides and strut lengths. The horizontal and diagonal strut ends touch on the Flis drawing.

On the actual Redstone tower, the horizontal struts go all the way over from side to side.
The diagonal strut ends are welded directly above and below the horizontal struts.

On this build I'll glue the horizontal struts first and then add the diagonal struts with the angled ends butted up against the horizontals.

Secrets of Estes Modeling, Part 1

In a blog comment, David Carllucy sent me the link to this article by Mike Dorffler telling how Estes builds their catalog models. This copy was in Sport Rocketry magazine but is worth repeating. 

      Secrets of Estes Modeling
by Mike Dorffler, Estes Industries

We break down the method to build a good quality model into specific tasks, then bring these together almost like an automobile assembly line. We plan it out before we start. That way if you screw up one task you can redo that portion and go on. It's much more difficult to completely build the model and then try to paint it. We build the engine mounts, fins, body tube assemblies, etc., finish them as necessary, then bring them together.

We do fins like this. First of all, we replace the balsa with basswood. It's nuts to try to fill and finish fins made from balsa. The basswood is much finer grain and finishing goes so much faster, the results are superior. Go find yourself some Sprayon brand industrial primer light gray #00341. Peel the sales label off the basswood sheet and use some lacquer thinner to rub away any of the adhesive left on the wood from the sticker. Use some 400 wet or dry paper and sand both sides of the sheet smooth. Then stand the wood up on one end against a cardboard box or similar and power drive a heavy coat of the primer into one side. Let this dry and repeat for the other side.

Sand again and paint again. Then sand the sheet again almost back down to the wood itself. Once you have tried this you will immediately see why it works so well.

Now use the balsa fin you are going to replace as a pattern and trace it on the basswood sheet the appropriate number of times. Cut the fins out with a razor blade or X-Acto. We don't use a bandsaw because the fin edge will chip no matter how careful you are. Sure, you could cut them about a 1/16" oversize and sand them back, but it's more work than just blade cutting them in the first place. Sand the fin edges smooth while occasionally stacking them all up to see if they match. Take the 400 and just kiss the edges where they meet the fin sides to make a small radius. Don't make the effort to try to radius all the fin edges. I don't want that. They look better if the edges look almost square. Put a piece of plastic bag over the end of your finger and seal all the fin edges with cyano EXCEPT the root edges. You can actually do this now or after the fins are attached.

We seal the body tubes with a heavy coat of gray primer, sand, seal again, and then sand again. Use whatever tube marking guide or method you choose, but use only a pencil to mark the tube for fin and launch lug placement.

Anything but pencil will get absorbed by the paint pigments. We run straight lines the entire length of the tube so you can sight down them when attaching the fins. Also, to get the lines straight we use two-foot lengths of 1/2" aluminum angle. You just lay it on the tube and it's automatically straight.

First run a set of alignment lines the length of the tube, spaced appropriately for the fins. Then run another set next to the first, spaced the thickness of the fins. The idea here is that you will attach the fins BETWEEN the lines and you can see immediately whether they are straight or not. Now take your pencil and put cross marks on the tube where the fins are going to be making narrow rectangles. Use a narrow sanding bar or those little finger nail sanding strips to sand through the primer and back down to the 'brown' of the body tube.

Build the engine mount, test-fitting it in the body tube as you go along. Paint it flat black when done. Also paint the inside of the body tube flat black where the mount will go just deep enough so that you can't see the brown on the inside. Install the engine mount using epoxy. We use the 15 minute type which allows enough time for adjustments before it sets. We don't use Titebond here because, when it dries, the water in it makes 'coke bottle' type impressions around the body tube where it was applied inside.

These are the Estes methods for building catalog and trade show models.
Over the years I've used similar ideas, like building in sub assemblies and filling all grain and seams before gluing it all together.
Interesting to note: "It's nuts to try to fill and finish fins made from balsa." But, balsa (or now Tung wood) is included in most all kits.
On occasion I use basswood, it's stronger and easier to finish.
Mike mentions using epoxy for engine mounts: "We use the 15 minute type which allows enough time for adjustments before it sets." We've all figured that one out! 
I wouldn't recommend painting the inside of the engine tube flat black, that might interfere with inserting an engine. Again, this is how they build for catalog and face card pictures.

Wednesday, December 17, 2014

FlisKits Mercury Redstone Build Part 6 Fin Air Rudders

Here the pencil lines are drawn down the taper line using the extended lines already drawn on the instruction sheet.

Cut the basswood edge off down to the leading edge on both sides of the Air Rudders.

I used a four sided fingernail file to taper the Air Rudders first.

The Air Rudder squares were a little loose on the basswood.

I added strips off packing tape to both sides to help hold them onto the sheet.

Use the pencil line as a taper reference.
The leading edge tip is a knife edge.

Sand the tapers on opposite sides. The kit included six air rudders. Four will be used in construction, two are extras.