Sunday, May 31, 2015

Centuri Draconian Marauder #5336 Build, Part 8, Missile Launchers Part A

The missile launcher heat sinks needed many cuts to free them from the card stock.

The instructions show the first two heat sinks simply glued to the sides of a dowel. These first two heat sinks would end up low and not centered on the dowel. All the remaining pieces would end up even more off center.

I used one of the other heat sinks pieces to raise up the piece I was gluing.

This was repeated on the other side and did put the root edges down the center line of the dowel.

Before gluing any of the heat sinks, be sure they are straight and flat!

On the left is after removing from the sheet, the inset shows it straightened out.

Saturday, May 30, 2015

Centuri Draconian Marauder #5336 Build, Part 7, Wing and Rudder Prep

The wings and rudder got a shot of primer / filler.
With all the edge preparation some edge fill was needed.
Both wing sides were glued together and weights set on top.

I found it interesting that I had to glue the wing halves together with one die cut top up, the other one down. I wish the die cutting was set up with both top sides facing up. Without surface prep (sanding down the bottom crimps from the die cutting) one half of the wing would have raised edges.

Some of the razor blades might have been a little long.
Some inside corners were over cut and needed a little glue fill.

With the wing halves even at the back, the front tip needed to be trimmed to match up.

5/20 13mm Engine Adapter

I know Estes has new plastic engine adapters, but sometimes I like to go old school.
Most all of us know a 13mm T engine casing fits into an 18MM empty casing. An 18mm casing will fit into a 24mm casing.
In this case my 13mm engine was too tight for the 18mm casing I had.

Take the tip of your knife to start the peel inside the casing.
Start the inside peel at one end using long needle nosed pliers.

Don't just pull straight up. Peel a bit and let go with the pliers.
Grab again, this time lower down the peel. Repeat.

When you get half way down, turn over the casing and start a second peel from the other side. You should meet the peels in the middle.

You'll still have to friction fit the engine in the larger casing.

Fred Shector made this suggestion on TRF:
TIP: Start the masking tape just over the top of the casing. this prevents the tape from rolling back over itself inside the mount.
It also make for easier removal after the flight.
Don't cover the ejection charge!

Here's the 13mm A10-3t engine in the 18 mm adapter.

Believe it or not, this A10-3t engine in the larger casing actually weighs less than a 18 mm A8-3 engine!

Friday, May 29, 2015

Centuri Draconian Marauder #5336 Build, Part 6, Engine Mount Assembly

The wide centering ring is tight over the engine hook.
The hook was held inside and traced for width with a pencil.
TIP: Don't mark and cut the relief slot over an inside spiral wrap seam.

Score and peel off a few inside layers.

The inset picture shows the new fit over the engine hook.

The large centering rings are glued to the back, The forward ring butts up against the wide Centering ring. There is 1/4" between the two rings.

The engine ring spacer (between the large rings) was used to help spacing. It'll be glued in place later after the mount is glued into the body tube.

Old Cox Engines

On TRF in 2013, Krusty posted some pictures of some Cox Rocket Engines.
These were three B6-6 engines from 1971.
Instead of printing directly on the brown casing, the Cox engines got a paper wrap, like the imported Quest engines.

To see the 1972 Cox catalog, CLICK HERE 
The Cox rockets were heavy, molded of a high impact plastic.
I never saw any Cox rockets or engines in my local hobby stores.
DCastle asked:
"Were these relabled Estes engines?"
Bob Sanford responded:
"No, Cox had their own motor making machines.
These machines existed until the early 1990s when they were broken up for scrap."

What stopped production? I was told: 
The engines were produced indoors, in the same large building where ALL the Cox products were produced. Black powder dust was everywhere, even settling above in the rafters. A spark ignited the dust and there was an explosion.

These were always an interesting feature of the Cox engine package. The igniters reminded me of a match head. You would plug them into an adapter at the end of the wire lead. No micro clips!
If you wanted to fly an Estes engine with nichrome wire igniters, you couldn't connect the Cox launcher leads to them!
Cox included FOUR igniters in a three engine package. Estes and Centuri used to include an extra igniter, but later only packaged three igniters, one per engine.
The newer "Starter" igniters (no pyrogen on the tip) aren't as reliable. Estes now packages four Starters, one extra in each engine package.

Thursday, May 28, 2015

Centuri Draconian Marauder #5336 Build, Part 5, Before and After

This is the front and back of  the landing gear pieces.
The right picture is the smoother top side cut, the left is the CA'd and sanded back side.

The front landing gear piece has some inside rounded curves.

They were rough when removed from the card stock. CA was applied and the round edges smoothed with 400 grit wrapped around a dowel.

The wing supports weren't cut very straight and had "nubs" on the corners.
Again, CA and sanding made them more presentable.

TIP: When applying CA, keep it off the edges that will get glued during assembly.

Better Kevlar / Shock Cord Knot?

Quest kit instructions show a very simple overhand knot to join the Kevlar and Elastic ends of the shock cord.

It works fine but I never cared for this knot. I always look for something cleaner.
I knew there was a better way to join the two lines.

Here's how I was joining together the lines.
It works, I've never had a break or separation.

Yes, I know the Kevlar should not go over the tube edge. This is just for the picture.

This might be my new knot choice.
It's called an Albright Knot.
This picture and instructions are at the Animated Knots website: CLICK HERE

I like this knot because it is smaller and cleaner.
Like the Duncan Loop Knot (used to tie the shock cord to the nose cone screw eye or lug) the ends are parallel to the line going into the knot.
Very secure, both cords aren't going anywhere!
I only used four wraps of the elastic, not ten like shown above.

All knots take practice. You probably won't get it right the first time. Everybody uses different knots to tie the recovery system together.
This is what works for me right now. Find what works best for you.

EDIT: In the comments below, Eerofluge made the following suggestion:
"The Albright Knot is often used to join thicker leader material to fishing line, which is a good application for joining a thick shock cord to thinner Kevlar cord. However, usually the thicker line forms the single loop (gold cord in example picture) and the wraps are made by the thinner cord (blue cord in the picture)."

Thanks Eero, I'll have to try it both ways and see how the knot lies.

Wednesday, May 27, 2015

Centuri Draconian Marauder #5336 Build, Part 4, Wings

The wings were cut free from the thick card stock with a sharp knife.

The root edges of the wings weren't cut straight.
A few passes with 220 on a block closed up the gaps.

This is the rudder piece.
Under a light you can see the raised areas along the outside cuts.

On the finished model you can see both sides of the wings and rudder. The raised edges will be removed here, too.

Sanding alone will just give you a fuzzy edge.
Rolling on some medium CA hardens up the surface for easier, fuzz-free sanding.

The front landing gear support piece also got cleaned up.
Here I'm sanding down the raised edge with 220 grit.
If any fuzz shows, reapply some CA and sand again with 400 grit.

A Little Canaroc History

On YORF, Pterodactyl posted a link to a Canaroc news story: CLICK HERE

To check out a Canaroc catalog go to Ninfinger's - CLICK HERE

Tuesday, May 26, 2015

Centuri Draconian Marauder #5336 Build, Part 3, Engine Mount

You can't just sand the raised areas off and end up with a smooth surface.
Brush over the raised areas with medium CA applied with a Q-tip.
Sand with 220 on a block to surface. Apply more CA and sand smooth with 400 grit.

I wouldn't normally bother with the raised edges but these surfaces will be seen on the outside off the finished model.
This picture was taken before the ring on the bottom was trimmed to match the upper ring.

The rings were sprayed with primer/filler and sanded.

On the left is the top smoother side.
On the right is the bottom side with the raised edges that were CA'd and sanded down.

The fit of the rings was very loose.

The centering ring will end up 1/2" from the rear of the engine mount tube.
For a wider outside diameter, a glue stick was used to adhere a single wrap of 20 lb. copy paper.
That was enough for a good fit of the rings.

MRN Idea Box TIP- From February 1969

Mojo 1986 was selling some older Estes Model Rocket News (MRNs) on Ebay.
For me, one of the most valuable pages was "The Idea Box".
I did some screen grabs and will feature some older ideas that still have some value today.

"This safety cap by Hervert H. Maston of Lavonia, Georgia works well as a wind direction indicator in addition to its primary function. The tube may be a plastic straw or an LL-2D launching lug.
The flag may be of red plastic tape or of painted PRM-1."

How many eyes were poked by people leaning over the launch rods?
Launchers are typically low to the ground and I'm sure it has happened enough to justify including rod caps with launchers.
This one is a great idea as the safety cap also works as a wind direction indicator.

I put together a PDF of a Launch Rock Safety Cap.
It's a great, simple addition for your next launch day. Print, cut and glue around a launch lug.

This PDF only took up half the sheet so I added some more safety flags to choose from.

If you'd like a copy of the PDF, email me at:
and request the Launch Rod Safety Flag PDF

Monday, May 25, 2015

Centuri Draconian Marauder #5336 Build, Part 2, Engine Mount

These offset rings are actually outside the model off the rear of the extended engine mount tube.
The two large engine rings were a little off.
You can easily see the engine hook notches weren't cut the same.

The rings were stacked to check alignment.
At the the bottom you can see the lower ring is a little out of round.
This overhang was traced with a pencil and cut off with scissors.

The crooked notch was re-punched so both were the same.

The corners were re-cut so they were straight and square.

Here's one of the problems with die-cut thick card stock.

The side that was facing up during the cutting has a slightly rounded edge. The back side has square edges.

Around the back edges the card stock is raised, buckled from the pressure of the cuts.
See the next post for a "fix".

MRN Idea Box TIP- From December 1967

Mojo 1986 was selling some older Estes Model Rocket News (MRNs) on Ebay.
For me, one of the most valuable pages was "The Idea Box".
I did some screen grabs and will feature some older ideas that still have some value today.

The original Estes copy:
"You can do a perfect scale job on a bird which is normally not equipped with launching lugs and still fly it with regular launch systems thanks to this clip-on launching lug suggested by Ed Brown of Florence, Colo., and of Estes' Machine Shop Crew.
Select a piece of body tube of the same diameter of your bird and slit it as shown. Glue a launching lug on the outside opposite side of the slit. When ready to fly, just slide the unit to the C/G of your bird and prepare to launch as usual."

On one of my models:
I did this on the FlisKit BT-5 based Mecury Redstone.
The 1/8" lug would look too large glued to the side of this small scaled model.
The tube collar is a little loose and does need a piece of tape to hold it on for flight.

Sunday, May 24, 2015

Centuri Draconian Marauder #5336 Build, Part 1, Parts

This one turned out to be one of the weirdest builds yet!
The way the model was engineered was interesting but required some extra primer and sealing steps.
If you were to just punch out the pieces, glue it together and paint, you'd end up with many rough, bulged edges.

I picked up two of these on Ebay for a very reasonable price.
In the mid to late 1970s, many Centuri kits had die-cut card stock fins instead of balsa. These two had LOTS of layered card stock.

Centuri called the Marauder fins "baffled, multi-layer" wings.
Making a model like this out of balsa would have been difficult. Thick card stock construction solved many problems.

Here's all the parts.
There are four sheets of die-cut card stock in three different thicknesses.

The parts of interest:
The LONG blow molded nose cone. By 1979, Centuri was steering away from the two part molded nose cones.
The shock cord mount is just a small piece of card stock, maybe too small.
The clay nose weight is hard but still usable.
One of the two ST-7 missile launcher tubes was a dark purple color. Held up to a light it was almost translucent. I've never seen a body tube like this before.
In the second picture is the "Super" decal sheet. It's not really super, it's about 1 1/2" x 4".

MRN Idea Box TIP- From December 1966

Mojo 1986 was selling some older Estes Model Rocket News (MRNs) on Ebay.
For me, one of the most valuable pages was "The Idea Box".
I did some screen grabs and will feature some older ideas that still have some value today.

The Original Estes Copy:
"McLean, Va. is heard from as Steffan Parcells suggests a reel for the leads from the Electro-Launch to the Launch Controller.
The wire can either 1/8" welding rod or a piece of clothes hanger wire."

Enlarge the picture for a better view.

This as basically a cord wrap tool.
It is much better than just tightly wrapping the cord around the launch controller.
Launch lead wires are much thinner and more delicate now. This wrap tool makes an effective "strain relief" for the cable.
Most controller failures start when the wire breaks from flexing at the exit point at the top of the controller.

From an Ebay listing, here's an example of cables wrapped too tightly.
On the right side of the top four cases, the thin lead wire is bent sharply right out of the plastic casing. Chances are, some of the copper wire is already over flexed and broken.
I wouldn't bid on these! 

Here's how I wrap the lines.
At the top there is no strain on the lead line. The hole where the lead exits has a sharp enough edge that it could cut the cord.
The line leaves the controller straight up - not bent down at a 90 degree angle.

Take the extra moment to wrap your lead lines loose. Your controller will last much longer than just a few launches.

Saturday, May 23, 2015

MRN Idea Box TIP- From December 1965

Mojo 1986 was selling some older Estes Model Rocket News (MRNs) on Ebay.
For me, one of the most valuable pages was "The Idea Box".
I did some screen grabs and will feature some older ideas that still have some value today.

The original Estes Copy:
"Remove those dents in balsa nose cone, etc. by the method suggested by Jim Merriman of East St. Louis Illinois. 
Put a drop of water on the dent and touch lightly with a wood burning pencil or soldering gun. 
Heat and moisture will swell the wood fibers and refill the depression."

One thing the article didn't mention - 
This tip is for bare wood (not finished) nose cones. If the nose cone is finished you would have to fill and sand the dent (or Estes smile) smooth. 

All the wood is still there, the fibers are just compressed making the dent.
Water and heat will swell the wood and raise the depressed area.

I wouldn't apply a soldering iron directly onto the wood, you might burn the balsa.
Wet a paper towel and set that over the dent. Then set the hot soldering iron over the paper dowel.
This will protect the balsa surface.

Friday, May 22, 2015

FlisKits Honest John Finished

On the left is my older Fliskit Honest John, it has 21 flights.

On the right is the new replacement.

Since the first Honest John build in 2010, my decals are turning out better.
The ink is darker and more dense.
I was hoping the nose cone decals would fit the diameter but they still had to be cut apart and set down individually. The spin rockets look better now.
In this kit, FlisKits doesn't include decals anymore.

MRN Idea Box TIP- From March 1965

Mojo 1986 was selling some older Estes Model Rocket News (MRNs) on Ebay.
For me, one of the most valuable pages was "The Idea Box".
I did some screen grabs and will feature some older ideas that still have some value today.

The original Estes Copy:
"Get the right engine block position for sure with one of these gauges.
A few layers of 1/2" masking tape wrapper around one end of an engine casing makes engine block installation a deft one-move operation without fear of freezing out of place.
The 1/2" unit give proper positioning for upper stages, the 1/4" unit allows the engine to be taped to the engine tube for easy installation and removal.

Here's my engine block "gauge":

In LPR, most all engines extend 1/4" out the back of the engine mount tube.
Instead of just pencil marking the engine spacing guide tube at 1/4", wrap tape around and engine casing 7 or 8 times at 1/4" from the low end for a positive "stop". Cut off the tape that extends over the end of the casing.

Apply glue far up inside the engine mount tube. Set the engine block in the tube end then push it in place with the casing until the tape wraps butt up against the tube edge. Remove the casing tool - Done!