Friday, September 21, 2018

Steampunk Protostar #11, Just Nosing Around....

The next part of the build is to prepare the model's nose.

A quick aside - I'm trying to train myself to abandon some of the model rocketry terminology that was engrained in my brain back in the 70s, and start using the more modern versions.  Things like 'nose' instead of 'nose cone'; 'motor' rather than 'engine' (though Estes still uses 'engine' in their literature); and 'starter' as opposed to 'igniter'.  Old habits die hard, and you will probably still see some of the old stuff here on the blog.  But I'm trying.

There is nothing particularly unique about prepping the Protostar nose co....er...nose.

One item that the instructions didn't address is filing down the recovery attachment eye after the mold flashing is removed.  There will be remnants of a sharp line of plastic that, if left in place, could cut into the shock cord over time and cause a failure..  A little work with a small needle file takes care of this.

A bit of scraping with an X-Acto blade takes care of the nose's molding seams.









The Protostar kit comes with three pats of clay for nose weight.

Since the hole in the nose base is fairly large, the clay pats are quite easy to install and tamp in place with a half inch dowel.

Rinse and Repeat 2 more times.








A little bit of CA is dripped into the cone to help hold the clay in place.

All done!

That's a fairly heave nose.

Next post - It's on to yet more plastic parts sub-assembly - fin pod prep.

Thursday, September 20, 2018

An Astronomical Interlude

A couple of posts back, I mentioned that my grand-kids were over for a visit on Saturday, during which we built the three models in the Estes '3 Bandits' kit.

Later that evening, I happened to look outside and see a bright, nearly first quarter moon hanging in the sky.
I pulled out my old 60mm refractor telescope from the closet, and set it up on the back deck so that the kids could view the moon.  Lots of  Ooohs, Aaaahs, and "Cool !"s as we took turns observing all of the craters, mountains and plains highlighted along the moon's limb using a 25mm eyepiece.

While we were out, I noticed that Venus was hanging well above the western horizon, so I trained the telescope on that object. To my surprise, the seeing (degree of atmospheric turbulence) was very good, and we could distinctively see Venus' 'half disc' phase.

A further scan of the sky along the ecliptic revealed yet another of the bright planets. 
"I'm betting that's Jupiter"  I told the kids.  The view in the telescope optics confirmed it.  More exclamations from the young 'uns as we were able to make out the north and south equatorial bands and two of the Galilean moons using a higher power eyepiece.

"Grampa, what is that one?" one  of the kids exclaimed, pointing further eastward.

I looked, and to my surprise, there was a bright reddish steady object. 
Mars.
The telescopic view didn't show too much remarkable there.  A small reddish disc.

It was then that I noticed, about halfway between the moon and Mars, another fainter steady object.
"No way!", I said,  "That's got to be Saturn!"

Sure enough, the ringed planet was easily visible and a pleasant sight at around 100x. The planet currently is at a point in its orbit where the rings are near full inclination to our view. More gleeful reactions from the kids.

I was pretty thrilled at all of this myself, mainly because I had never before observed the moon and the four brighter planets so closely aligned along the ecliptic, and observable on the same evening.

It was truly a great day with the grand kids for model rocketry and solar system visual astronomy!


Wednesday, September 19, 2018

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.


Tuesday, September 18, 2018

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….

Monday, September 17, 2018

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.

Friday, September 14, 2018

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).

Thursday, September 13, 2018

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.