An Agglomeration of Andromedas (MPR)

[les]

COMMON INFO
Well, off to another 3 way build.... I've done a trio of Tridents and the Mars Snooper Mayhem.
But a slight issue, one is LPR, another is MPR, and the last is HPR.
Where to put the build thread? Average to MPR?? But then LPR or HPR folks may miss it......
I decided on creating 3 threads, one in each sub-forum. There will probably be some cross-referencing between the threads.

So what am I building? The thread title tells some of the story. I have:
Semroc USS Andromeda (LPR) - Clone of the Estes model, 18mm motor
Q Model USS Andromeda (MPR) - 1.65X upscale, 24mm motor
Wildman USS Andromeda (HPR) - 3X upscale, 54mm motor

I've had the Q model kit sitting around for a while. I had planned to clone the Estes size version, and bought some parts for it, but never started it. Then Semroc came out with their clone. I was thinking of starting the two, when Wildman announced he was coming out with a 3X version. So.... off we go
END COMMON INFO

 

[les]

Some people might question building the Q model - it is a collectors kit.
If anyone wants it, let me know....
5...4...3...2...1... too late

The kit parts. Notice that the large sail fin is two pieces due to its large size.


Here is a shot of the tubes with the Elmer's F&F. I tried using Chris Michielssen's approach of using an exacto knife to apply the F&F directly into the spiral. A little more tedious, but I did find sanding the tube after was a lot easier.

 

[les]

I glued the two pieces for the sail fins together - sorry - forgot to get a picture, and then sanded the joints smooth and papered the entire fin.

 

[les]

Q-Model always used a laser cut system to mount the fins. Marking the tube and installing the system.



A centering ring is glued tot he bottom. I used some clamps to hold it in place while the glue dried.

 

[les]

COMMON

Wanted to show the differences in the sizes of the sail fins

END COMMON

 

[les]

Some centering rings on the motor mount, then time to glue the motor mount into the body tube.



For this I mixed up a bit of 15min epoxy. You need time to align the slots in the tube with the fin mount system and I was afraid wood glue would grab too quickly. Side note - the directions actually call out to use CA for the majority of the construction. However, CA can be brittle and break so I primarily used wood glue and double glue joints (see my LPR thread for a description of this if you are not familiar)

To ensure the slots were aligned, a clamped together a jig to keep the fins straight.

 

[les]

I should discuss the design/build of this kit. The instructions include 3 options for the build:
1) One big rocket with chute out the top larger tube. Pro - easier to pack chute. Cons - transporting this long rocket with large sail fins without damaging it and possibly crinkling body tube on recovery.
2) Build a special dowel and L-joint system so the rocket can be separated in about half for transport. Pro - easier to transport, easier to pack chute. Cons - harder construction, potential separation point failure, and crinkling tube on recovery
3) Build the rocket to separate with 2 chutes, one for each half. Pros - ease of transport, eliminates potential of crinkling body on landing. Cons - Now need to pack two chutes and shock cord in the small diameter tube and potential recover failure. They state "with practice and compact packing techniques it is possible to pack the recovery system..."

I'm actually thinking of a variation to option 2 but without the complex L-joint. The first and potentially easiest would be to 3D print a screw coupler, similar to the latest version of the Estes Mean Machine. Unfortunately, I don't have a 3D printer......
Another variation is how I did the US Rockets version of the upscale Trident. I would glue the heavy coupler onto one end, and drill and tap multiple holes for screws.
Pix from my Trident build


My concept would be to use #4 truss head black screws and would look something like this



Thoughts? Suggestions?

 

[les]

The Q-Model kit also comes with jigs that require assembly



The jigs get used to attach trim to the pods, attach pods to the fins, align sail fins to tube, align fairings and antenna

Used the jig (and kitchen island) to attach the sail fins.


I did discover the tabs for the pod fin would not reach the inner tube, so a glued and trimmed some extensions. Honestly - I didn't notice if the sail fins had a similar problem, but they were already glued in. I think they were good, but just not 100% certain.... Too late now.

 

[Wally Ferrer]

I should discuss the design/build of this kit. The instructions include 3 options for the build:
1) One big rocket with chute out the top larger tube. Pro - easier to pack chute. Cons - transporting this long rocket with large sail fins without damaging it and possibly crinkling body tube on recovery.
2) Build a special dowel and L-joint system so the rocket can be separated in about half for transport. Pro - easier to transport, easier to pack chute. Cons - harder construction, potential separation point failure, and crinkling tube on recovery
3) Build the rocket to separate with 2 chutes, one for each half. Pros - ease of transport, eliminates potential of crinkling body on landing. Cons - Now need to pack two chutes and shock cord in the small diameter tube and potential recover failure. They state "with practice and compact packing techniques it is possible to pack the recovery system..."

I'm actually thinking of a variation to option 2 but without the complex L-joint. The first and potentially easiest would be to 3D print a screw coupler, similar to the latest version of the Estes Mean Machine. Unfortunately, I don't have a 3D printer......
Another variation is how I did the US Rockets version of the upscale Trident. I would glue the heavy coupler onto one end, and drill and tap multiple holes for screws.
Pix from my Trident build
View attachment 428050View attachment 428051

My concept would be to use #4 truss head black screws and would look something like this

View attachment 428052 View attachment 428053

Thoughts? Suggestions?

I think that would work, you could even use nylon pop rivets for the assembly. As long as your recovery is soft enough, I wouldn't worry too much about crinkling on landing...

 

[les]

COMMON with LPR
Differences in build sequence

LPR version - the pod fins are glued to the body first, then the pods are glues to the fins.
The fairings are glued to the body first, then the dowels are glued to the fairings and sail fins

MPR version - the pods are glued to the fins, then the fins with pods are glued to the body.
The dowels are glued to the fairings first, then glued to the body and sail fins

The differences are partially due to the differences in the jigs. Both had pros and cons....

END COMMON

So for this construction, glued the dowels to the fairings, and then sanded even. - sorry for the different orientations



I again trimmed the jig (one side done) and then glued the fairings on. The fairings wanted to pull away from the body tube so I used a rubber band to hold them until the glue set.

 

[les]

I installed the pod fin assemblies. The instructions want you to use the small jig to ensure they are square. I found it was too big and cumbersome and was too busy trying to hold the jig, rocket, and fin to take a picture. But they are on!

You mark the center point of the dowels and antenna, and glue the dowels onto the antenna. Before I did that I did sand and round the dowel ends (the instructions do not call out for this). Forgot to get a pix (bad day).

But I did get a pix of attaching the antenna to the sail fin. Rather than use their jig a used one of my squares.

 

[les]

Went with using 2 - #4 screws on each side. Drilled and tapped first hole. I then installed a screw to ensure nothing "slipped" before drilling the other holes. I did drop from 3 per side (as marked) to two.



The directions call to install two centering rings for the larger top tube. The top most one is supposed to be 1/16" from the edge, but the edge itself was cut with a 1/16" cant.

But the exact placement really isn't that critical.

A hole needs to be drill in the top ring. The kevlar cord is tied around the tube and passed through the hole. Sorry, but missed this picture too...

Also filled the mold line on the nose cone with bondo and sanded.

 

[les]

This shows the larger tube glued to the centering rings.
An additional ring is added for the transition. NOTE - shown before gluing in place



The transition comes with a separate glue tab. I use a nose cone to help form the cone. And installed.

 

[les]

Sorry for the delay - various life events....

The kit came with a jig for placement of the detail panels. Use it for marking, then gluing.

 

[les]

Launch lug - I'm not happy with their design. You get about a 2" length of 1/4" lug that you are supposed to cut in half. One part glues to the fins/radiator rings and the other half glues to the fairing. This rocket is about 6' tall. Once the fairing clears the rod the rocket then only has a 1" lug to guide it as it continues to accelerate.

Instead I'm going to leave the 2" lug intact and glue it to the fins/radiator rings and then glue another lug using material I have to the fairing.

 

[les]

Views of attaching the lugs - I used the rods from the Wildman Andromeda to align them!

 

[les]

One interesting difference with the Q model. On the Semroc version, there are some disks mounted on the small tube and in line with fairings. The Q model version has you place the disks on the large tube and between the fairings. One of the build options has you mount a dowel for separation and the disk would cover it. However, two other build options do not require the dowel, but the instructions still have you place the disk where the dowel would have been. I penciled in where the disk would go. I decided not to install the disks - and I already have some "detail" with the screws to hold the two halves together.



Basically ready to prime now!

 

[les]

Common Info

Thought I would show the different nose cone profiles

The Semroc is scale. It has multiple angles.
Q model is elliptical
Wildman is pointed

 

[les]

Primer - the great equalizer. Hides certain faults, shows others. But gets things to a uniform color...
Easier to find things and not get hung up on stuff that is ok but looks bad due to color differences

 

[les]

FINALLY getting back to this.....
The transition really needed cleanup. Applied some F&F



Also found fillets I missed or needed cleanup

 

[les]

Finally got around to painting the bloody thing. A few runs to clean up (only showing one)



Also disappointed in the body tube. Various spirals showing through.
Trying to decide about fixing them. They don't really show from a distance.
I know some people don't even fill the spirals, and others need the mirror finish.....

 

[neil_w]

Once you've reached that stage of paint I wouldn't worry about the spirals. It'll still look fantastic.

 

[BABAR]

Finally got around to painting the bloody thing. A few runs to clean up (only showing one)

View attachment 438279 View attachment 438280

Also disappointed in the body tube. Various spirals showing through.
Trying to decide about fixing them. They don't really show from a distance.
I know some people don't even fill the spirals, and others need the mirror finish.....

View attachment 438281

Maybe in the year 2350, interplanetary ships that never enter the atmosphere WILL be constructed with spirals intentionally (since air resistance will not be an issue), maybe for the same reason as out paper tubes are, It may be more efficient to build them that way in space!

I always like the, “Oh I meant to do that,,,,,” approach.