Steampunk Protostar #10 - Finishing Up The Engine Mount / Tail Section

I don't have a lot of confidence in the use of cardstock centering rings for motor mounts.  Especially for withstanding the thrust load of a D or E engine.

Back in my old fleet days, I had an Estes Big Bertha that, on its 6th or 7th flight, the card stock engine mount broke loose during boost and shot straight up through the body tube.  The model crashed and crinkled up the top three inches of the tube.  I was able to cut off the damaged section and continue flying the Bertha in a bit of a shorter version.

I don't relish the idea of a similar thing happening to a model on which I will have invested a lot of time building and detailing.

Over on Hans Chris Michielssen's Model Rocket Building Blog  (I highly recommend checking this blog out if you haven't already), there is a very good solution to this very problem. 

Chris simply cuts out some braces from scrap balsa and glues them between the card stock centering rings.  These keep the rings from flexing during boost and add a lot more strength to the entire assembly.  Even though they add a little more weight to the tail end of the rocket, I think the trade-off is very good insurance.

Here is a pic showing that simple construction process:

One small task which I should have done before even assembling the motor mount is this:

I absolutely loathe the finger tabs on Estes' latter-day engine hooks.  I just think they stick out too far and detract from the looks of the models. Plus, they aren't really necessary. 

Real Model Rocketeers don't need any stinkin' finger tabs, right?

So, I simply cut them off. 

A good heavy duty plier/cutter makes short work of this task.  Actually, the hard metal is easier to remove if it first gets a good scoring cut with the cutter.  The end can then be easily removed by bending it back and forth until it just snaps right off at the score line.  The sharp edge of the remaining hook can then be cleaned up using a metal file.





A couple of other small procedures to finish up:

A line of CA gets applied to the fore end of the engine hook, just in case.

And some small chamfers are sanded around the top edges of the centering rings.  These are meant to retain a line of glue at the ring/body tube joint when the motor mount is installed later.







Lastly, it's a good idea to perform a dry assembly of the engine mount and tail assembly into the main rocket tube, just to make sure everything inserts and fits right before any glue is applied.  Once engine mounts are glued in, they are impossible to remove in order to fix things.

Perfect fit!



I am not going to install the engine mount at this point in the build, because the tail cone is destined to get some additional Steampunk detailing applied.

Also, the proposed painting operation will be better accomplished separate from the main rocket to eliminate having to perform a lot of complicated masking.

BAR Fleet #118 Bandit 3

Source:  Estes Industries

Kit #: 2435  1 of 3

Type:  Sport Model

 Stages: Single

Engine Type: 13mm
Recovery:  Streamer or parachute

 Length:  27.8cm

Diameter:  18.8mm
Weight Empty:  17.8g
Nose Cone:  Tangent Ogive
Fin Type: Combination / plastic fin can
Number of Fins: 4

Color Scheme:  White, Violet w/ orange, violet, and green trim.

Date Completed:  15 September, 2018

 A Quick Build Kit

 Saturday, September 15, 2018, my two oldest grandkids visited my home.  They indicated that they would like to build another model rocket, so it was off to Hobby Lobby to pick out some kits. 

They chose the ‘3 Bandits’ E2X kit because we could each have one to build.  This would actually be good because I could instruct them step by step as I built mine.

 The kids selected the green and orange versions as their preferences, so I got the one with the violet color scheme.  The build was extremely simple, taking around an hour, including helping the youngsters build theirs.  The only difficulty I had was in trying to peel the many decal ‘stickers’ from the backing paper without the use of an X-Acto blade.  Poor eyesight and big, clunky fingers conspired against me!

I found the model’s engine mounting system to be rather interesting in that the casing is intended to be supported solely by the internal tabs and rings of the plastic fin/engine unit.  The engine is retained by a removable plastic ring that clips onto the rear of the fin unit.

I have a bit of skepticism about how durable this arrangement will be after a couple of flights.  I envision a melted plastic fin unit from the engine heat, but I’ll just have to wait and see.

If the fin unit doesn’t survive, I can always re-purpose the body tube and nose for another future model build.

Anyway, this model provided somewhat of a refreshing change from the more advanced models I’ve been constructing over the past few months.  No cutting, sealing, sanding, masking, or painting required.  A great model kit for spending a quiet afternoon with the grand-kiddoes doing something constructive and fun. 

It’s not really a bad looking bird either….

Steampunk Protostar #9, The Plastic Tail Section

Now that the core of the engine mount is completed, the next step is to prepare and install the plastic tail cone that came with the kit. 

After carefully cutting it away from the molded assembly per the instructions, the unit requires a little bit of work before it can be installed on the motor mount.  None of these steps are addressed in the instructions, by the way, but are pretty intuitive.

First the cavity for the engine hook must be widened with a needle file so that the hook can fit and move freely when the tail section is installed.

Second, the plastic 'flange' at the tip of the tail cone most be removed so that the unit can fit cleanly over the engine tube.  I used a Dremel rotary tool equipped with a drum sanding attachment followed by a curved needle file to fine tune.

Now is the time to dry fit the tail cone to its position on the engine mount to make sure everything works.

If all is well, the tail can then be CA'd to the engine mount per the kit instructions.  The main point to watch here is to make sure the top of the tail cone lines up precisely with the aft paper centering ring.

 

The final operation for the tail cone is to remove the unsightly molding seam lines.

This can be accomplished quickly by using an X-Acto knife as a scraper. 

Holding the blade at a 45 degree angle, the blade is drawn backwards (away from the cutting edge) along the seam line.  It effectively shaves off the excess plastic. 

A little more work is done with some fine sandpaper to smooth things out nicely.

On this build I am not going to worry about any depressions along the seams, as the lines will later be completely hidden by 'Steampunk' detailing.  If I were building the Protostar as stock, I would be using some thinned CA to fill the seams and sand smooth.

Steampunk Protostar #8, The Motor Mount

The next phase of the Steampunk Protostar build is the motor mount/tail sub-assembly.

To start off, the main mount parts are put together in accordance with the kit instructions, so I won't go into a step-by-step treatment here.

I'm still not positive about whether I like the new Estes kit instruction format.  The illustration-only presentation is OK, but it tends to leave out a lot of construction details (and potential pitfalls) that accompany each step.  I sometimes try to place myself in the shoes of a novice model rocketeer who might not have a lot of building experience attempting to navigate these directions and build this model by pictures only.

 

Iffy, at best. 

 

This method might work well with LEGO sets, but for a free-flying model meant to be powered by fairly hefty rocket motors - not so much.

Anyway, off of the soapbox and on to the model...

The only thing I did different with the basic mount is to move the forward centering ring back about 3mm.  This allows for the application of a good filleted glue joint between the ring and motor tube.
The kit instructions show the ring glued flush to the very end of the tube.

As for the engine hook retainer ring and aft centering ring, it is extra important to place them EXACTLY at the dimensions specified in the instructions.  The location of these parts will dictate the proper placement of the plastic tail cone later on.  Again, it would be helpful if the instructions had a short written blurb stressing the importance of this small detail.

The final touch to the basic mount is to apply a good glue 'fillet' to the interior engine block/motor tube joint.
Build 'em strong, sez I....

Next post will tackle the prep and installation of the tail cone and a few other extra details (that aren't in the instructions).

Steampunk ProtoStar #7, Still More Fin Prep

"The power of the Mighty D Engine compels you....The power of the Mighty D Engine compels you....The power of the....."

Oh !....Yes.....AHEM......Protostar......

The next step in fin prep/construction is to glue the two halves of each unit together.

This is done using double glue joints after which the fins are placed between sheets of waxed paper and a couple pieces of plate glass. 

A weight is placed on top to keep everything flat and in place until dry.

Once the completed fins are dry, they get another quick overall sanding.

Here are the completed fins.  They will be set aside while other Protostar assemblies will be worked on.

 

 

 

 

 

Steampunk Protostar, Part 6 - More Fin Prep

Now that I have finished posting about re-unions, Flatcats, and Canopii, I can finally get back to the Steampunk Protostar build series that was started way back in June...

Today's rocket building exercise involves a continuation of preparing the Protostar's fins.
This step consists of providing the first bit of  'Steampunk' detailing - specifically, poking a series of holes in the fins.

I have no idea what these holes are for, other than serving as fancy detailing. 

The Victorian design engineers probably know, but they're not divulging any secrets!

I'm only the project's construction grunt.  Those other guys are probably off somewhere in their 'smoking parlor' tipping back a glass of Sherry and engaging in 'merry talk' and 'sallies of wit"!

Anyway...the fins.....

The first step is to mark out the hole locations.  This is done by making a cardstock template of the upper fin section, drawing a guideline using a  French curve drafting tool, and spacing the hole locations.  (Wait a minnit...French curve?  This is supposed to be strictly an English build!)

The four hole sizes will be graduated from 5/16" diameter to 1/8" in 1/16" increments. 

Here, the 3 upper fin sections and the template are stacked, aligned and pinned into position, ready for drilling the holes.

In the interest of keeping this build true to the Victorian-era spirit, I had originally intended to use one of my antique 'egg-beater' hand drills to  make the holes in the fins.

 

But, for the sake of precision and accuracy, I opted out, and resorted to the electric drill press instead.

A plywood backing board placed under the bottom fin helps to prevent drill bit 'tear-out'.

Here is a pic of the drilled fins. Balsa wood is generally very unforgiving with the use any kind of power tools, so there is a bit of tear-out material in the holes that must be cleaned out and smoothed.  Sandpaper and fine needle files will be used here.

Just noticed another interesting vintage tool appearing  in the photo's upper left corner.  Yep, kiddies, a good old fashioned scratch awl can be effectively used in model rocket building!

Back In The Day, #14 - It''s Deja Vu All Over Again!

As I have been wrapping up the final details of the recent Canopus-2 and FlatCat rocket builds, I took some time to descend the dark, dank staircase that leads to the secret BlastFromThePast rocket la-BOR-atory, activate the hidden secret bookshelf and pull out a large secret notebook labeled  'Old Fleet Model Rocket Inventory'.
This massive loose-leaf tome was put together back in 2016 and contains data sheets, any existing photos, and flight information for every single model in my old timey fleet.
Since I had very few photos of my earliest rockets, and flight data recording was very sporadic in those days, it was quite a task to piece together the history of those first 103 model rockets. 
Much of the information was gleaned from memory, which at my age is...well, you know....

Anyway, I discovered something very interesting  - the model rockets with fleet numbers 8 and 9 were - Canopus 1 and a FlatCat boost/Glider, both built in 1974!

44 years later, I find myself building new versions of the same models in exactly the same sequence.

Fleet #8 - Canopus


I did not have any photographs of this bird, but did, at some point, sit down and make a half-scale drawing of the model which I was able to salvage (peel) from an earlier scrap book and mount in the new notebook. 

This drawing even shows the color scheme of the original rocket.  Looking back, sky-blue and black were probably not the greatest paint choices for a rocket that was expected to reach a considerable altitude.

I have absolutely no flight data on the rocket, other than it was launched five times.

The final flight was dated 15 June, 1974.  It took place at a demonstration launch hosted by a fellow Colorado Springs rocket club, the Rapirhawks, headed by Warren Layfield. 

The only notation I have on this flight is "Model was lost".

I'm reasonably sure that a couple of the Canopus' flights were in cluster configuration.

A rocket engine inventory/usage log for 1974 indicated the use of four 1/2A3-0T engines. 

At the time, there were no other rockets in the fleet that would have used such engines, so I surmise that they were employed to help boost the Canopus on at least two of its flights.






Fleet #9 - FlatCat B/G

Built in 1974 from an original MPC kit, the FlatCat did not see its first launch until 11 June, 1975.
The bird was flown as built using a B6-4 engine.  A flight log states that the flight was somewhat successful, but the engine delay was too long for any lengthy glide phase.

Later on, the model was modified into a sliding pod rocket glider.  The dual vertical stabilizers were removed and replaced by a single center v-stab in the manner of more common glider designs.

The model was flown four more times with varying degrees of success:

4 April, 1976 - B62
13 November, 1977 - B4-2
22 January, 1978  -  B4-2
6 August, 1978  There is no flight data on this one other than the notation that the model "crashed and was destroyed".

This is the only photo I have of this bird, showing it in R/G configuration:

 

CHEERS!