Friday, December 15, 2017

True Modeler's Rocket Kits NASA Scout Build, Part 3, Nozzle Forming

The shroud and rear nozzle are printed on manila file folder card stock. Its a great material for shrouds.

The straight lines are cut first with a new blade and strait edge. After the straight lines are cut use scissors for the curved arc lines.

TIP: Before forming the nozzle check to find the smooth side of the card stock. Sometimes one side of the card stock that is smoother than the other side. Form the curve with the smoother side out.

Enlarge the picture and you can see the bottom image shows the smoother side. That side should end up on the outside of the shroud.

Form the shroud by rolling a clean dowel with the card stock in the soft heel of your palm. This method works better than dragging the card stock over the edge of a table top.
You'll just have to try it once to see how smooth the curve can be. No creases and no wrinkles.

Also form the inside glue tab over a dowel. This puts a small curve into the tab so it will be less visible under the shroud ends.

Baffles - Which Side Up? Part 2

On the N.A.R. Facebook Page, Joseph Barrett asked:

"Which is top and which is bottom? Also the build thread I’m following says to spray the lower half of the Executioner with high heat spray paint. Is this necessary?"
According to the Centuri instructions, the tighter set, centered holes should go towards the bottom of the rocket.
Centuri originally designed it, I'd go with their recommendation.

I did add a smoothed coat of wood glue to the rear facing sides of the disks before they were glued onto the coupler. I don't think high heat paint would be needed.

My Semroc Centurion (with the Centuri style baffle) had over 15 flights when I opened it up.
To see the surprising autopsy - CLICK HERE

Thursday, December 14, 2017

True Modeler's Rocket Kits NASA Scout Build, Part 2, More Parts

More parts of interest:
You are supplied with two sheets of shrouds. EVERY KIT SHOULD SUPPLY YOU WITH AN EXTRA SHROUD. You can make two of each, two nozzles and two 5/50 transitions.
Two lead fishing weights, two different sizes.
Shroud lines, pre-cut.
A 16" black nylon parachute with metal grommets
A peel and stick roll pattern

The fins are pre-cut from basswood.
Notice the root edge is marked with pencil.

Here's a closeup of the 5/50 centering rings. You can see how one is glued inside the other.

On the right is the same ring after being sanded flat.

Baffles - Which Side Up? Part 1

On the N.A.R. Facebook Page, Joseph Barrett asked:
"Which is top and which is bottom?
First, a little background:
The baffle that Joseph is referring to was a Centuri Patent design.
Centuri introduced this style of baffle first in 1971 with the Centurion kit.
To see that catalog page, CLICK HERE

The Estes Bandit with their "Ejection Ducting System" came along a year later in 1972.
The ejection gasses had to go up, hit a bulkhead and exit out punched side holes into an outer tube. The ejection then traveled down, then up again past a notched top ring to eject the parachute.
Compared to the simplicity of the Centuri baffle, the Estes system reminds you of a Rube Goldberg drawing.

Wednesday, December 13, 2017

True Modeler's Rocket Kits NASA Scout Build, Part 1, Parts

I don't know a lot about True Modeler's Rocket Kits, I picked this kit up on Ebay.
The website is still online, the last update was in 2009. I've emailed them to find out if the kits are still being produced but haven't received a response.

This kit is a scale model of the NASA Scout, # TMRK9801.
The model is 30.25" tall and flys with A8-3, B6-4 and C6-5 engines.
The lowest tube is a BT-60, the upper sections are BT-50 and a BT-5.

Some parts of interest:
The conical BT-5 sized nose cone.
Two thick 5/50 centering rings, made up from 5/20 rings glued into 20/50 rings.
1/8' wide elastic shock cord, a little short at 16" long.
A small tri-fold shock cord mount printed on thin paper.
Three pre-cut fins, cut from 3/32" thick basswood
20/50 centering rings die-cut from thin cards stock.

The Worst Kit?

I was asked recently what was the worst kit I ever built?
That's a hard call, I don't want to offend any vendor. Here's one from a company long out of business.

The Die Fledermaus was a boost glider from the Union Stadt Zepplin Works.
The picture on the right is from a review by Matt Gillard on Rocket Reviews: CLICK HERE

In my old rocket binders I found a 1977 letter from Robert Haley, the president of U.S.Z.W.
Robert was interested in me doing a review of his kit. My review would not have been favorable.

Matt Gillard had the same results I did. The build was difficult with vague instructions.
The written instructions were on one side of an 8 1/2" x 11" sheet. Enlarge the picture on the left.
The promo page called it a rocket plane. Rocket gliders (by NAR definition) don't eject the engine.

The full size assembly drawing was on the other side.
You have to warp balsa around the fuselage and form the nose from a block of balsa.

The A3-2t engine would eject and was supposed to glide at a 6 to 1 glide ratio.
Mine got 20 feet up and power pranged into the ground!

Tuesday, December 12, 2017

New Duplicolor Primer/Filler?

Paul K wrote on YORF:
I've been using both Dupli-Color Filler/Primer and 3M Bondo Filler/Primer for a number of years, both are fast drying, very sandable primers, that can take just about any paint, especially the lacquers I like to use when possible. The 3M Bondo dried a little faster, the Dupli-Color filled a little better, so I'd use them based on how much fill I needed.

Well, the last can of Dupli-Color I bought had a different label, but is still called "Filler & Sandable Primer".

I used it on a large plastic nose cone, and immediately noticed it was a bit darker gray. No big deal, I thought, so put on a few light coats like I usually do. When I went to sand it with 320, it clogged up the sandpaper very fast, more like some enamel primers I've used. The stuff is awful! 

PaulK followed with:
The Dupli-Color 2-In-1 (Bad stuff) is the new one with 8 ingredients
The Dupli-Color Filler Primer (Good Stuff) is the old one with 14 ingredients.

My response:
I bought two cans of what I thought was a "new" label filler/primer at Advance Auto. I couldn't find the grey label FILLER that I've bought before.
I got home, checked the product number on the old empty can of Duplicolor Filler/Primer
and knew it was a different formulation.

I went back to the store with the two, unused cans of the '2 In 1" label. I did find new re-stocked cans of the original grey label marked "FILLER" and exchanged them.

Look for the grey label that says "PRIMER FILLER". Check the back of the can for the number FP101 above the UPC symbols.

Great - More labels and more formulations to confuse everybody.