Semroc MMX Orbital Transport, KMX-01, Finished!

Without any size reference, this mini Orbital Transport looks like the full sized original.
The build is small and would be hard to fill the wood parts after assembly. I'd recommend filling the parts, seams and notches as you go.
The small glider could be tricky to trim for a good glide. I'll launch it eventually!

Semroc MMX Orbital Transport, KMX-01, Build Part 11, Decals & Finishing Up

Here's a bit of the Semroc instructions showing the decal placement.
The water slide decals are small!








Notice the bottom of the decal -
TIP: To fit against the wing you've got to cut right at the red ink border. The rest of this decal sides don't need to be cut as close.




TIP: Here's another decal that has a close cut on the bottom to fit right over the forward small canard fins.







I couldn't get the SEMROC ASTRONAUTIC LINES to line up on both sides. This is simply the way the decals were set. With the yellow globes even at the front, this is how the names line up on the right and left sides!




The toothpick is centered and stuck into the balsa shoulder of the nose cone. The Kevlar shock cord is knotted and pressed into the hole with the toothpick. Remove the toothpick, squirt a little glue into the hole and push the toothpick back in.

The streamer is taped to the shock cord.






The other half of the toothpick is stuck into the small glider/orbiter nose cone. This gives you something to wrap the balancing clay around when test gliding the orbiter. I haven't tested or balanced the glider yet.

Semroc MMX Orbital Transport, KMX-01, Build Part 10, Final Smoothing & White Paint

The launch lug is glued in place on the bottom center line of the main body.

I used some tape to hold it in place while some medium CA glue was applied with a toothpick. The small drop of CA was allowed to run down the joint.

The entire model got a shot of gloss white.

The picture shows the sanded rough areas that show up with that first coat of paint.

There was a lot of fine sanding with 400 grit to smooth out the fillets and some rough areas.

TIP: Some inside areas were painted with a brush.
I knew I wouldn't be able to reach these spots with the spray can. 







The glider was spray painted separately.

TIP: Mask off the inside of the notched hooks on the glider and main body to keep the paint out.

Here's the underside after a final coat of white.

The model is ready for the tiny decals.

Semroc MMX Orbital Transport, KMX-01, Build Part 9, Orbiter Glider Construction

GOTCHA: Something wasn't right. I had built three other full size Orbital Transports before.
Check the instruction photo showing the glider body tube. The front extends probably 3/8" beyond the front center tip of the wing. The kit supplied tube was too short!

Luckily I had some MicroMaxx sized tubing in the spare parts drawers. 



Good thing I didn't add those wing glue fillets!
I used a single edge razor blade to remove the wing and rudder. The new longer tube was glued in place.

The orbiter nozzle shroud is tiny!
You can pre-form it using a sharpened dowel end.

The glue tab was held shut with tweezers while the glue set up.
TIP: Use very little glue to adhere card stock shrouds and nozzles like this.

The nozzle is glued to a small disk and coupler to be slid into the rear of the glider body tube.

Semroc MMX Orbital Transport, KMX-01, Build Part 8, Orbiter Glider Construction

The dihedral of the glider wing is done by setting the joint over the glider body tube. When the outside tips of the wing sides touch your work bench, the angle is correct.

I also filled the joint at the wing center.

The instructions suggest glue fillets along the top joint of the wings.
I wouldn't recommend this - it isn't needed. Getting a bubble free fillet is difficult and adds a lot of weight.






One side of the template jig is used to set the elevon angle.







The notched hook is glued even with the front of the wing.
GOTCHA: Notice anything wrong here? More in the next post.

Semroc MMX Orbital Transport, KMX-01, Build Part 7, Motor Housing Gluing

The engine housings are glued into the remaining slots on the bottom of the wing.

These slots also require filling with CWF and smooth sanding.

The smaller auxiliary fins are glued on the top and bottom.
The small ones are on the top, the back of the orbiter glider rests on these. Like the small fins on the wings, the taller side is to the rear.

One of the supplied templates is used for positioning. Use the inside slots for these fins.

The larger auxiliary fins are on the bottom.
The outside slots on the template are used for these.

Semroc MMX Orbital Transport, KMX-01, Build Part 6, Wing Construction

The wings and other wood parts are thin! The lower wing had the tab break off before it was glued up.
Glue on the fairings on a flat surface.

The side wings got a fillet, applying the glue with a toothpick. Use a toothpick, the inside angle is too small for a standard glue bottle nozzle.






More filling is needed on the tab and slot joints.







The small upright fins are set in place to show positioning, no glue yet. Be sure the setting is correct, the taller side of the small fin goes to the back.

Semroc MMX Orbital Transport, KMX-01, Build Part 5, Engine Housings

The housings needed some fine fitting.
I used my small diamond file. The better fit is shown on the right.

The sides are glued on.
The inside corners are small so I used a Q-tip to even up the fillets.









Here's the assembled engine housings with the shorter center piece and lugs (engines) glued in.

As usual with laser cut slot and tab construction, these require filling. I used some CWF applied with a small brush.

Semroc MMX Orbital Transport, KMX-01, Build Part 3, Parts Prep

I didn't want to use the burnt launch lug "engines" on my build. in addition to the burnt edges, the lengths were inconsistent.
I have plenty of small launch lug pieces saved from previous builds. Four lengths were cut and the edges sanded smooth.

The laser cut parts are 1/32" thick basswood.

There isn't much grain in basswood but there is enough that it can be filled and sanded smooth.
I don't normally spray a sheet with the parts still attached, but these were small to treat individually.

The front and back of the sheet got hit with a good spray of Duplicolor Filler/Primer.


EDIT: When the build was finished I almost wish I had done a second shot of filler/primer and smooth sanding. There was still some grain showing. Still, it was much better than no grain filling at all.


Here's how one half of the glider wing looked after the filler/primer was sanded down.

All 36 pieces were held in a small zip bag until needed. I'd recommend keeping them all together - some are small and would be easy to lose.

Semroc MMX Orbital Transport, KMX-01, Build Part 2, More Parts

Parts of interest, from the upper left going clockwise:
The Engine Block - Maybe longer than needed, note the laser burnt ends.
Glider Hook - An improvement over the old dowel/launch lug connection.
Cardstock trim pieces - that glider nozzle is small!
Glider nose cone
Centering rings
Jet Engines - Badly burnt launch lug pieces. These will be replaced.






Semroc includes alignment jigs in many of their kits.
Initially it seems a little confusing. The instructions show what pieces are used in what steps.

The decals, like the rest of the model, are tiny!
For the full-size O.T. kit, Semroc sells a few decals in different colors. This MMX kit has the original red and black decor.

Semroc MMX Orbital Transport, KMX-01, Build Part 1, Parts

When the package is turned over, it looks like some parts might be missing.
All the laser cut basswood is inside the folded instructions.

Most parts were of good quality. The small laser cut launch lugs were replaced. The laser cutting melts the plastic Mylar on the lugs.

Semroc MMX Orbital Transport, KMX-01, Build Background

I remember getting this 1970 catalog in the mail!
The slick, new Orbital Transport was featured on the cover. This was Estes kit number K-42 and sold for $3.25.
The design was by Wayne Kellner. The kit was sold from 1969 through 1985.

No die-cut or laser cut balsa on this one! All 36 (Yes, I said 36) pieces of balsa were traced from patterns and cut by hand. Launch lugs and stand-off dowels were also cut to size.

The O.T. is still a fun launch. At ejection the orbiter usually glides well, circling around the booster descending under a parachute.

Estes re-released the kit in 2002. Surprisingly you still had to trace and cut out all the balsa!
Semroc has also released their version of the full size O.T. All the balsa stock is laser cut, the parts are notched for better alignment and easier assembly.
This next blog build will be their recent Micro Maxx version. Semroc claims it reaches 220' with a MMX engine. I don't think it'll get that high -
I have yet to launch this finished MMX Orbital Transport. About ten years ago I built a downscale carded version of the O.T. Boost was straight with a A10-3t engine. At ejection, that heavy card stock glider didn't glide!