Tuesday, December 30, 2014

FlisKits Mercury Redstone Build Part 20, Masking and Cleaning Up

I've masked and painted Mercury Redstones before but this was a small hard mask.
The Scotch tape strips look strange in the left side picture. More masking tape was added.
On the right is the reveal after the tape was pulled.
The horizontal lines were rough and there was some paint that got under the tape.
To clean it up I used some orange cleaner on a Q-tip. The swab was dipped into the cleaner and the excess blotted in a paper towel.

Careful wiping took off the black that rolled over the leading edge of the fin.
There wasn't much I could do with the horizontal mask. Some thin decal strips were cut and placed over the bad mask.

Here's the lower end after cleaning it up.
It's not perfect but good enough for me.

More touch-ups with a small brush are needed.

Keeping Fin Edges Square TIP

When sanding filler, primer or wet sanding between color coats you don't want to round over purposely squared fin edges.
On this Payloader II model the leading edges are rounded, all other sides are square.

On the right I'm sanding the flat sides of the fin right up to the squared edge.
Notice I make a "V" with my thumb and middle finger. With the sandpaper wrapped over my thumb it keeps it from getting too close or going over and rounding the square edge.
By varying the pressure and position you can get very close to the edge.

To sand the outside square edges, use sandpaper wrapped around a Q-tip.
Hold the fin under a bright light so you can see the gloss shine of the paint on the flat edge.
Just sand enough to dull the paint gloss.

Follow up with another undercoat.

FlisKits Mercury Redstone Build Part 19, Primer and Sanding

The fins were shot with primer/filler.
The air rudder joint had some fuzz that showed up when the primer dried.

The low end of the fin fillet (fairing) was sanded round with 400 grit wrapped around a Q-tip.

The upper half of the fillet was sanded with a sharp fold of 400 grit.

The first white coat followed. (Inset picture)
The square corner of a razor blade was dragged over the fin tip and air rudder joint to sharpen the inside corner. I'm not cutting here, just scraping a little filler and defining the joint.

Why Do They Go Up?

I'm sure some won't agree with this explanation. For me it explained the basics of thrust.

It's 1969, I'm in my eighth grade Science class.
I thought I knew everything about model rocketry. I'd been building them for a year and probably had a few dozen flights under my belt.

I was talking to my science teacher about my new hobby.
He asked: "What makes your rockets move?"
I tried to explain: "The thrust gasses push against the air outside the rocket. That friction makes the rocket go up and fly."

He said: "No, no exactly." He added something like: "The model moves because the pressure inside the engine isn't even."
What? I still didn't get it. (That catalog drawing with all the arrows inside the cutaway engine didn't make sense.)

He grabbed a piece of paper and pencil and drew some stick figures in a box.
The box has no bottom, their feet are on the floor under the box sides.
(I'll try to explain what he showed me.) 

"Here's Jim and Fred in a big cardboard box. They have a bet who will break through the box first. Jim is on the left, Fred is on the right. Both are pushing hard on opposite walls of the box.
First to break through their side wall wins."

"Fred (on the right) doesn't know that Jim (on the left) has installed a trick door on his side."

"With both pressing hard on their sides,
Jim hits the switch and the trick door on Fred's side pops open!
Which way does the box move?
With the door open and the back pressure released out that door, Jim's push to the left is what moves the box!"

Flip the box vertically, imagine it's a rocket engine.
"Think of the open door as the rocket nozzle. Fred's pushing effort is the escaping gas out the nozzle."
It's the upward push that gives the rocket it's movement.

This was one of those "AH HA!" moments.
My science teacher explained it in a way I could visualize and understand.

Monday, December 29, 2014

FlisKits Mercury Redstone Build Part 18, Fin Gluing, Fillets and Launch Lug

The rear of the fins overhang the rear end of the body tube.
The center low air rudder in the inset picture will have to be adjusted. It's leaning to the left.

Fillets were applied and smoothed wider at the bottom.
The real Redstone had a tapered fairing that was thin at the top and wide at the rear.
I might add some pull away plugs.

The launch lug and standoff seem too big for the model.
I'll probably do some sort of removable lug or a pop lug. I haven't made pop off lug in years.

Altimeter Hole Sizes? TIP

The Estes Altimeter instructions are vague about how big the pressure sampling holes should be.
They show small square holes, very hard to cut with an X-Acto knife.

Perfect Flight makes small "flashing count" altimeters for $25.00 CLICK HERE
From the Firefly PDF instructions here's some more in depth information:

Static Pressure Sampling Holes 

You must drill one or more clean-edged holes in the payload
compartment to allow outside air pressure to be sampled by
the altimeter (see table below for recommended sizes). These holes should be as far away from the nosecone shoulder and other body tube irregularities as possible (at least 3 times the body tube diameter or more) to minimize pressure disturbances being created by turbulent airflow over the body
tube. Sand the area around the hole as necessary to eliminate flashing or raised edges.
Best performance and greatest accuracy will be achieved by using four smaller holes distributed at 90 degree intervals around the body tube’s circumference instead of a single larger hole. When using four holes, each hole should be ½ the size of a single hole as noted in the table. This will minimize the pressure variations due to wind currents perpendicular to the rocket’s direction of travel.

According to the list above, the holes I've been punching in payload tubes have been WAY too large!
These are directions for the Perfect Flight Altimeter, not the Estes Altimeter. There might be a difference in the recommended hole sizes and different brand altimeters - who knows!

Sunday, December 28, 2014

What Part Is This?

Can anybody identify this rocket kit part?

No prize, I'm just curious if anyone knows what it is.
I usually keep small pieces in zip-lock bags and was surprised when I couldn't find it during assembly. I found it on the bathroom floor, of all places!

Answer in the Comments below . . .

FlisKits Mercury Redstone Build Part 17, Stabilizer Fin Unit

A fin pattern sheet is included but all the fins are laser cut.
It's a good thing, I wouldn't want to cut anything this small and try to get them consistent in size.

The fin marking guide is cut out.

The stabilizing fin unit tube is only 1/4" long.
I'd recommend setting it over an engine casing for support when gluing on the fins.

The inset shows two opposite fins glued on.
Look across the top to be sure both are in line and centered.

These fins are thin, long and tip heavy. It takes a few tries to get them to stick.

The finished fin unit.

It'll get a shot of primer/filler and sanding before being painted flat black.

The two tape disks for the streamer were paper.
I replaced them with Avery plastic rings.
The cotton string was tied on with a square knot.

Saturday, December 27, 2014

FlisKits Mercury Redstone Build Part 16, Fin Assembly

The surface of the card stock fin tips is glossy.
I lightly scraped the gluing area for a better bond.

The air rudders glue even with the bottoms of the card stock fin tips.

The inset shows a small amount of glue applied to the joint with a Q-tip.
The excess was wiped off making a very small fillet.

All four fins are complete.
The ruler gives you an idea how small they are.

Igniter Placement Tip

When setting an igniter in an engine, try this:
Set the igniter wires away from the launch lug position.
It's simply easier to connect up the clips when the igniter ends are oppossite from the launch rod.
The two wires should be placed between two fins opposite the lug.
If your igniter is not away from the launch lug or not between two fins, don't bend the igniter into this position. You could bend and cross the igniter leads.
Simply lift the engine hook and rotate the engine casing to a better position.

Notice the igniter leads are lightly bent up and turned to the side away from the open nozzle.
The leads are not straight down from the nozzle hole.
This keeps the micro clips away from the engine flame extending their usable life.

Friday, December 26, 2014

FlisKits Mercury Redstone Build Part 15, Fin Assembly

I did give the fins a shot of primer/filler before gluing them together. Basswood still has a small grain and these would be impossible to fill after gluing the pieces together.

Here the air rudders (still together on the sheet) and fins are taped down to a piece of cardboard for spraying.

The fins are stuck down on their root edges so no paint will get on that gluing surface. I'll have to sand the primer off the outside edges for gluing on the outside pieces.

After careful sanding with 400 grit you can see some primer/filler in the grain pores of the basswood.

After spraying, the air rudders were removed from the sheet.

The edges were sanded to remove any marks left from the laser cutting.
On the left - before sanding. The inset picture shows that edge after sanding smooth.

The card stock fin tip pieces are glued on the outside edges of the fins.

Take an extra moment and be sure it is centered and slightly raised up to match the cut at the bottom.

Whadja' Get For Christmas?

My older daughter asked what I'd like for Christmas.
On TRF, MyGypsy posted a link to the INCRA Rulers video CLICK HERE

This is one of those tools that could be invaluable.
The inset picture shows the small holes and slots that fit a .5 MM (fine) mechanical pencil. Instead of marking over the edge of a standard ruler, your pencil point goes into the holes and slots for more accurate marking!

Here's the link to the Incra Website: CLICK HERE

Thursday, December 25, 2014

Merry Christmas To All . . .

And to all a good night!

FlisKits Mercury Redstone Build Part 14, Tower Eject Housing

Before the dowel is cut to size, I'd recommend drilling a small hole for the tower spike.
The instructions just say to glue it on top. With it set in a hole it won't break off as easily.

Instead of cutting up the instructions, I cut new strips off the bottom of the sheet.

I ended up cutting the top band a little wider. It will be glued overhanging the top of the dowel and then sanded flush with the end. This way the top will end up smoother without a ridge from the glued paper rings.

Tack the end down first and let dry.

Run some white glue down the strip with a Q-tip.
The wider top wrap gets two full wraps, the two thin bands get one wrap.

On the upper left notice the pencil tick mark. All the band ends were started at this mark.

At the wrap start and overlap point a razor blade makes a very thin notch. (Notice the top band is starting to come off. It was glued back down before gluing down the channel strip.

A drop of glue was set on my work table. The root edge was dragged over the glue drop while the channel was held with tweezers.

I made two housings, I'll probably use the second try, the one on the right. The tower tip is just a little long.

Wednesday, December 24, 2014

TOP TEN for 2014

Here we go, Counting Down the
Top Ten for 2014
Some were great, some not so good, all were interesting.
10 is the not so good up to #1 - the best of the year,
Click on the names to see to the builds . . .

Warped plastic, heavy and under powered with a C6-3.

9. Estes SR-71 BLACKBIRD
A real PITA build! Impossible to shape body skins, not worth the effort.
I have to wonder how many sit in a closet, started and never finished.

A funny rocket even funnier when it blew up!

Centuri's well engineered OOP Starter Kit with a near perfect one-piece plastic fin can.

6. Estes PATRIOT
Strong BT-60 body. Better with a payload section and 24mm power.

Clearance kit prices dip low over most holidays.
Husbands have to convince their wives it's too good to pass up. 
More and more rockets are added to the build piles across the country.
4. Odd'l Rockets LITTLE GREEN MAN
Most fun I've had designing and a surprising stable flyer. 
This is also a self serving sales plug.

3. Fliskits MACME SHREW
A challenge getting all the small body segments to match up. Considering it's girth, good performance with MMX engines.

A great kit with a perfect fitting vinyl roll pattern. Highly recommended.

And the Best Build of the year . . .

Best built with a 24mm mount. It would be under powered with a 18mm C6 engine.
Success with a new spray paint, the Rusto Metallic. The Stiletto is always a favorite at the field.

Total flights for 2014 was 132, eight less than the 140 launches in 2013.
27 models were built and finished in 2014.
Click on the "Top Ten" below (under Labels) to go to listings from previous years - 

FlisKits Mercury Redstone Build Part 13, Tower Assembly?

The tower sides were too wide to fit against the escape rocket dowel! There wouldn't be enough contact to make a good glue joint.

I had a few extra sides made up.
The diagonal and horizontal struts were cut apart and trimmed a little shorter.
The second tower was glued up.
On the left is the first tower, on the right the second (slightly narrower) tower.
While the fit is better, to me it still looks too thick and clumsy.
I picked this thickness of plastic rods for strength, I knew they would be thicker than actual scale. Mr. Flis sent a letter explaining that the scale plastic rods would be a smaller diameter than what I used. It was a compromise, for strength and the local hobby store didn't have the thin plastic.
Even on the Estes and Centuri kits the tower structure was thicker than actual scale and had to be for strength. But on a model this small it looks clunky.
You've got to give credit to FlisKits for providing all the tower information and jig to glue it together. Building a tower is always a good exercise to see if you could really do it!
But, this time for simplicity I'll probably go with the kit folded card stock tower.

Tuesday, December 23, 2014

More New Estes Kits

The best news is - 
The 2" diameter (Centuri capsule) Mercury Redstone is returning!
This is the Liberty Bell version. They specify a C6-3 engine only for a 200' altitude.
This version has laser cut wood fins and water slide decals.

The upcoming Odyssey is a skill level 5 kit made for 24mm engines.
There are some scalloped body tubes on the back end.

Three different parts packages called the Mix N' Match will feature three models built around a BT-50, BT-55 or BT-60. These use the new fin can design with interchangeable fins.

The Flip Flyer is a helicopter recovery model that turns over when the three large blades release at ejection. It looks like it rotates with the open body tube down. The nose cone comes down by a 9" parachute.

A new 9" parachute and 24mm to 29mm adapters are also listed.
To check out the new products CLICK HERE

FlisKits Mercury Redstone Build Part 12, Tower Assembly

While the instructions show the tower base ring to be a single layer, I glued the two together for a thicker ring.
This is glued to the "shelf" on the nose cone.
The lower tower inverted "Vs" will be glued to the ring.
The raised lip near the base of the capsule was built up with CWF.
This assembly will be painted black.

I made a few extra tower sides to have extras to pick from.

The side of the tower joints was carefully sanded at an angle to better fit against the adjoining tower side.

In the picture, the vertical is turned down and away from the block to get the angle.

One side of tower was taped down.
A second side was held with tweezers and CA glue was set on the joint with the tip of a toothpick.

The inset picture shows the finished tower.
The struts are thicker than actual scale. With all three sides glued up it's stronger than you would think.
The finished tower will be painted red.

Monday, December 22, 2014

FlisKits Mercury Redstone Build Part 11, Tower Step 5 V Braces

At the top of the inverted "V" the tips were cut at an angle.
The very tip point is cut off for a flat end for the tower side low end.

The inset shows the bottom ends cut off  (both even) with the razor blade.

The "Vs" are very small and easy to lose!
I'll keep the "Vs" on the sticky side of a strip of masking tape until all is assembled.