Big Girtha Rebuild Part 2 Fins

The Big Girtha fins were more of a Big Bertha shape.
The kit fins were used but needed a little more on the leading edge to match the shape of the original Girtha.

There was enough kit balsa to add to the leading edge.
A fourth fin was cut out.

The Big Bertha has four 1/8" thick fins, the Big Betty's three fins are 3/32" thick.

All four fins were pinned together and sanded to the same size on a block with 220 grit.

These fins will be covered with copy paper like my first Girtha.

Big Girtha Rebuild Part 1 Parts

To rebuild the Big Girtha I'll be using parts from a Quest Big Betty kit bought on Ebay.

This kit is older, most all the parts are great quality.
The die-cut fins were a bit rough, typical of most cut fins when the blades get dull.
The nose cone has minor seams and the white plastic has some streaks in it.

Parts of interest, clockwise from the top:
The stick-on "decal" name is HUGE! I'm not a big fan of the type font.

The shroud lines are pre-cut and very thick.
The "Gripper" shroud line fasteners are die cut Tyvek.
The engine hook is interesting. The upper bend goes over the top of the yellow engine mount tube hooking over the top of the engine block. The engine hook is spring steel and doesn't easily bend.

Big Girtha Autopsy

If you missed the earlier post about my "lost" Big Girtha -
The Big Girtha is a 2 engine cluster Big Bertha built from a Quest Big Betty kit.
At the February Tampa TTRA launch it drifted away after a great boost on two Estes C6-5 engines. I had a video camera taped on and hoped to get a good video. It was found and stored in the TTRA trailer until I made it back to a launch. The camera was gone! I found out Brian U. pulled the camera for safe keeping. I hope to get the camera back soon!
The model was ruined by water, there is some water in the field.
This model is a favorite and I have two Big Betty kits upstairs. Time for a re-build - with as few improvements!

I'm salvaging as much  as I can from the weather worn Big Girtha for the re-build.

The plastic nose cone is fine and will be re-used.

The body tube was cut open.
This is the upper side of the baffle. After four flights you can see what little of the ejection charge got through on the tube walls. While I probably could have used the old baffle, I'll make a new one.

The piece of body tube used for a shock cord mount is still in place and well glued.

The nylon parachute and shock cord are in great shape and will be used again.

The two engine cluster mount had some water damage and the centering rings were de-laminating.
The black electrical tape wraps look like new. If these wraps were brown masking tape they would probably be coming off.

The only thing I can use again are the engine hooks.

Old Models On Display At NSL

John Boren (Estes, JumpJet on YORF) and Bill Stine (Quest) brought plenty of classic models to the National Sport Launch this past weekend in Pueblo, CO.
There were 10 tables with 450 models on display!
Check out the pictures starting at post 44:
http://forums.rocketshoppe.com/showthread.php?t=12539&page=5&pp=10

Original Model Missiles from the Stine Collection:

Just a few brought in from Estes, some are the same models seen in the old catalogs:

Estes brought the new black powder 29mm E16 and F15 engines.
Also on display were new Pro Series E2X models.
I wasn't there, wish I was! These pictures were copied from the YORF posts.

Estes Bullpup Build Finished

A classic Estes kit, everybody has one in the build pile.
The model shown above is the rebuild of one of the first kits I built when getting back into the hobby.
I wanted to refinish with opaque white paint and water slide decals. "Real" decals certainly look better than the kit supplied stickers.
This one has squared fin edges, the new build is identical except has rounded leading edges.

Estes Bullpup Build Nose Cone Lug Fix

An Email from Orlando R.O.C.K. President J. Brian Coyle:

Knowing you, you've probably already finished and flown the Bullpup a few times... ;)
But today's post about the nose lug flash reminded me of a concern.  The Bullpup requires a bit of nose weight.  I don't like relying that tiny piece of plastic to avoid separations. (Especially true if folks don't replace the too short stock elastic).
It's better to drill a pair of holes into the base and make a Kevlar loop to attach the recovery harness.
Can't wait to see this one!  Especially your new decals.

Thanks Brian - good tip!

Taking the suggestion from Brian's email, here's how I fixed it.

On the left is that lug with the shock cord tied on.
On the right - 
I cut a slot into the nose cone shoulder. 
Only one hole is cut in the angled shoulder, the elastic is fed through the already open base hole. 
Start with a smaller hole drilled with a older X-Acto blade.
This hole was enlarged into the rounded slot using the small diamond files.
No sharp corners on this slot, I don't want the elastic to wear through.
Not shown, The old plastic loop was cut off. 

As Brian suggested, you could use Kevlar instead and make the loop.

Estes Bullpup Build Comparison - Old and New

Here's my old Bullpup, refinished with new home printed water slide decals.
The silver stripes (either side of the U.S. AIR FORCE) are more of a grey, no metallic shine at all.
The red stripes should be closer to a dark orange, but that's just how my home print decals turned out.

Above is the new build Bullpup using the water slide decals packed with the kit.
The silver decals have a shimmer to them. The rear fins have rounded leading edges and are slightly larger.

I was pretty happy with the font matches.
The "weight" of the fonts are close but not perfect.
The old build will be part of my active fleet.

The new unflown build will probably be sold on Ebay!

Estes Bullpup Build Part 10, Decals

Here's the address for the Jim Ball Scale Website:
http://www.rocketryonline.com/jimball/jimball/construction/pup/default.htm

This are the decals ones I redrew and printed installed on my old Bullpup build.
The "silver" bands on the home made decals were drawn a little long on purpose.
To help line these up, look over the leading edge.
These will be trimmed up (shown in picture three) after they are dried a bit and are better adhered.

A paper strip was wrapped around the tube to help line up the "Cradle Here" decals. All are at the same distance from the leading edge tip.

Now that the silver strips have set up they can be trimmed to the root edge joint. You'll need to let these dry and adhere better before trimming.

Use a new blade and lightly cut just the decal skin.
If done correctly you won't see the cut line.

Those eight black bars go to the trailing edges of the fins.
I used another paper strip with a pencil tick mark to be sure they were all the same distance from the root edge.

The forward stripe goes right above the nose cone shoulder joint.
After trimming off the clear edge with a razor blade the edge was a little rough.
TIP: I used a red Sharpie to run the red color under the shoulder lip. Now when the nose cone is in place no white or grey primer will show at the top off the body tube.
This doesn't always work, the permanent marker may not match the decal color. Black marker is always a good match. Other colors, not so much.

Estes Bullpup Build Part 9, Decals Information

The Estes instructions say to use the face card picture for decal placement.
The problem is, it only shows one side. 
Viewing from the rear, we'll call this the right side - the nose cone facing to the right.

I did a web search for pictures and came across the Jim Ball scale site:
HERE
That link will take you to the Bullpup page. At the bottom you can visit the home page - lots of great information there.

Here's the "right" side off my re-finished Bullpup.
Decals are applied as the facecard shows.

If you were to apply the right side decals first with the nose cone to the right -
Set the model on a table top and rotate it 180 degrees so the nose cone is facing to the left.
The decals shown here are now on the opposite side.

This second picture is from the Jim Ball's site shows a (slightly elongated) Bullpup with the decal view from the "left" side.

If the real Bullpup were hanging under the wing of a fighter jet, you could read the warnings and U.S. AIR FORCE (right side up) from both sides of the missile.

Launch! Schoolyard, May 25, 2013

Central Florida is heating up and the winds start earlier each day.
I was at the Schoolyard at 7:00 a.m.

I don't fly MicroMaxx models much anymore but today I loaded up the ASP WAC CORPORAL with the TINY TIM Booster.
The ASP MMX designs are all great flyers, altitude was probably over 100 feet.
The Mylar streamer makes it easier to follow and find. I stuck the landing.  

The Quest Cobalt ORANGE flew to an estimated 275' with a Quest A6-4 engine. At ejection the parachute did not pull out of the nose cone.
I'll stuff the shock cord and Kevlar line into the nose cone cavity first then pack the parachute on top of that. At ejection the shock cord (under the parachute) would normally pull everything out - not this time.
No damage. This one still looks like new!

The Odd'l Rockets UP! CUP didn't have one of it's better flights.
With an Estes C6-3 it turned 45 degrees to the West!
There was no wind and for the first time it didn't fly straight up. Maybe some rod tip off?

In the inset launch picture you can see a street and home. It landed in the gutter on this side of that house.

My refinished Estes RED MAX had a perfect flight with an Estes B6-4 to an estimated 350'.
This was an early build and I installed an 18" parachute, thinking the original kit had a chute that large.
I taped the shroud lines together to keep the chute from fully opening. The tape slid down the lines when the chute opened.
No problem and little drift landing 200' from the launcher.

Last up was my well worn Semroc THUNDERBEE with an Estes 1/2A3-4t.
The Semroc webpage says it'll reach 450' with that engine.
Two of the three fins have broken at the root edge. This model might be a good candidate for a string tether anchored at a fin root edge for a horizontal descent.

The last three flights were witnessed by a group setting up exercise mats on the basketball courts. All three flights got applause.

Estes Bullpup Build Part 8, Primer and Paint Sand

After lightly sanding down the gray primer you can see the primer left in the gain pores.

A light coat of gloss white followed.

Hold the surfaces under a bright light and you can see some rough spots.
Lightly sand these spots with 400 grit, dry.
Don't wet sand yet, the paint cover isn't thick enough. The water might get down into the tube and balsa.

This is the same fin after lightly sanding the first light coat of white.

When sanding between coats you just want to dull the surface. You won't need to sand off all the paint.

Estes Bullpup Build Part 7, Primer and Sand

There's one disadvantage to using the Titebond Molding and Trim Glue.
Enlarge the picture and look close at the leading edge tip and ends of the launch lugs.

Even if you try to clean up the ends when smoothing the fillets, the TM&TG leaves small glue blobs. The middle of the fillets are smooth, just the ends need sanding after the primer is applied.

There were some interesting molding ridges on the nose cone that you wouldn't see until the primer was sanded down.

Estes Bullpup Build Part 6, Engine Mount Glue and Alignment

The plastic tail cone is used to push the engine mount to the correct distance inside the body tube.
Continue pushing the plastic tail cone until the shoulder seats against the body tube and remove it.

From the top, I used a rounded end dowel to smooth out and remove excess glue from the fillet on the upper centering ring.





Before gluing the tail cone in place slide it in dry with no glue.
Rotate the tail cone until it it evenly centered around the engine mount tube. Left pic is before, inset pic is rotated and centered.
After finding the center, mark the tail cone and body tube with an pencil.
After applying glue, rotate the tail cone to the center mark.


Look at the instruction illustration at the top:
The instructions direct you to apply plastic cement to the shoulder of the tail cone. If you do this, you'll have glue squeeze out the back when you push the tail cone in the tube.

You'll be best off using a line of epoxy in the back of the body tube. This way the glue is pushed forward inside the tube.
Turn the tail cone to the center marks from the last step.

Estes Bullpup Build Part 5, Fin Gluing

I'll be installing the engine mount in after the fins are on.
No real reason for this, I just glued the fins on first. With no engine hook on this model I won't have to center it between two fins or opposite the launch lug location.

There were no instructions so I made a fin marking guide out of a strip of paper wrapped, marked the overlap then folded into quarters.

After marking the fin positions with pencil, a straight strip of paper was taped around the rear of the tube, 3/4" from the end. The rear of the fins will be at the 3/4" top of the paper strip.

TIP: I could have simply pencil marked the body tube four times at 3/4" from the rear. I'll make one pencil mark at 3/4" then wrap the strip at that mark. The strip guarantees that all fins are exactly the same distance from the end of the tube.
After the first fin was tacked on, a strip was wrapped around the leading edge tip for alignment of the other three fins.




The same idea is used at the front for the smaller fins.

Estes Bullpup Build Part 4, Plastic Parts Prep

Most every blow-molded nose cone will have a seam.
This one was pretty clean and only needed the ridge sanded off with 400 grit. No filling was required.

The back end lug was closed.





Don't use a knife to remove the lug flash. It's too easy to cut through the lug.
Use a small rat tail file to keep the hole round.
Any rough edges could wear against the tied on shock cord.

I didn't need a razor file to remove the adapter ends.
A few turns with my knife was enough to take them off.
The knife easily stayed in the shoulder grooves while scoring the plastic.

Wrap some 400 grit around an engine casing and sand a more rounded end.

Estes Bullpup Build Part 3, Instructions

This bag of parts didn't include the Estes instructions.
Easy enough to find them at JimZs: HERE

I also found a great Peter Alway drawing online.
The small end of the tail cone isn't really round.






From the Estes instructions:
Take a look at the balsa grain direction in steps 3 and 6.

Estes Bullpup Build Part 2, Fin Comparison

Here's the first older Bullpup build.
Look close at the white paint on the fins.
It's almost translucent, you can see the balsa grain through the paint. I was using the cheap $1.00 a can WalMart paint back then.
For whatever reason, the launch lug wasn't painted.
Check out how thick the stick-on decals are!

I'll be refinishing this old model at the same time I'm building the new kit.
New water slide decals will be drawn up from a scan of the kit decals.

There are slight differences between the two versions of the kit.

The larger rear fins are slightly smaller on the older (water slide) version of the kit.
The front small vanes are the same size.
On this side the decals are on upside down - more on that later!

Estes Bullpup Build Part 1, Parts

I'm sure everybody has built one of these.
I built a Bullpup when I got back into the hobby a few years back. My kit was a later version with the stick-on decals. Like most, I've always hated stick-ons.
I bought another and did a kit-bash to make a convincing sport scale MX-774.

This "kit" was bought from the JonRocket trailer at a recent R.O.C.K. launch.
There were no instructions included, but for $5.00 I didn't pass it up.

Here's all the parts next to my original built up Bullpup.

This early kit included the water slide decals!
All the die cut fins were broken off the balsa sheet.
The blades were dull when these fins were cut out.

The pieces of interest -
The tail cone/adapter,
Yellow thrust ring spacing tube,
3.5" long engine mount tube,
Too short length (16" long) of elastic, not rubber
Water slide decals! (Worth the $5.00 sale price alone)
1/2 oz of melted clay nose weight
Separated die-cut fins, 3/32" thick