Enerjet by Aerotech, Astrobee D Build, Background

My mistake - 

Aerotech needs the Astrobee D built before the Strong Arm, I'll be shifting builds and get back to the Strong Arm later.

This is a tall rocket, the largest I've ever assembled.

It's a scale model. As the info block reads: "Nearly 6 feet long - Almost one half size of the actual sounding rocket!"

Here's all the specs - 

There are two parachutes as the body splits in half at ejection.

Enerjet by Aerotech Strong Arm Build, Part 4, Strakes

On the left is the front of the strake, on the right is the rear.

The final tip cuts are marked with pencil.

Cut them a little wide outside the pencil lines. Then sand to shape with a block.

TIP: It's easier to visualize the shape by turning over the strake and checking the bottom.

I drew a centerline to better see the wedge shape.

Enerjet by Aerotech Strong Arm Build, Part 3, Strakes

Here I'm cutting the back of the strake.

Notice I'm cutting a little outside the pencil line.

The top picture shows the rough cut using a knife.

Here's the same cut after sanding with 220 grit on a block, followed by 400 grit on a sanding block.

Another before and after picture - 

220 to take down the rough cuts then 400 grit to smooth.

This inside angle is tough to smooth out.

Mark the side with a pencil and use a finger to block the block edge from cutting in too deep.

Enerjet by Aerotech Strong Arm Build, Part 2, Strakes

The strake material is white plastic, 12" long.

Be sure to check the lengths of the four strakes.

Set back to back, one strake was about 1/16" longer than the other three.

Even them up before trimming the strake shape.

Use a pencil to mark the side of the strake cuts.

The top picture shows the rear of the strake.

The bottom picture shows the front half of the strake.

At first I tried a razor saw but the raised base made it difficult.

It's also hard to get a straightedge onto the surface to use as a cutting guide.

I ended up simply cutting the lines freehand. I cut a little wide knowing I would do the final shaping and cleaning up with a sanding block.

In the two pictures on the right side - 

This obtuse (inside) angle cut is the most difficult.

Start and stop your cuts right at the apex of the inside angle.

The upper picture shows one cut.

The strake is flipped over in the second picture showing the start of the cut from the center to the outside edge.

Enerjet by Aerotech Strong Arm Build, Part 1, Parts

Out of the box, all the parts are of high quality.

There is a second body tube, same length as the tube on the left, without fin and launch lug slots.

The tube in the upper center is a coupler to joint the two 2.6" diameter tubes.

The instructions mention "Aero-Fibre" centering rings. The kit now includes plywood rings.

The black ring in the lower left is an screw on aluminum motor retainer.

 

The strakes are molded in white plastic.

These are trimmed to shape. The inset picture shows the profile.

The conformal rail guides are 3D printed.

The black launch lugs fit a 1/4" diameter launch rod.

The decals are peel and stick.

Enerjet by Aerotech Strong Arm Build, Background

 

Here's my latest build for Aerotech.

The Aerotech mid-power kits now carry the Enerjet name.

It's a big model for me at 44" tall.

It resembles the General Dynamics AGM-78 Standard ARM. 

All the Specs:

The build starts tomorrow!

Enerjet by Aerotech Initiator Build, Part 13A, Launch Lugs

A little backtracking to show the launch lug attachments in the body tube slots.

   

The kit includes (squared) plastic launch lugs and conformal rail guides. The client asked for the squared launch lugs.

Like the fins, there are pre-cut slots for the rectangular tab underneath the base of the lug.

The top of the plastic lug overhangs the top end of the body tube slot. The back end is even with the low ends of the slot.

When cutting out the die-cut slot, try to make the low end clean and square. Don't make vertical cuts below the base end of the launch lug. 

I had painted the tubes and launch lugs before assembly, the launch lugs were molded out of black plastic.

You should cut away the paint for better glue adhesion.

I used lines of masking tape to guide the knife blade line and score into the paint. 

On the right side picture, the tube is flipped over.

The paint was scraped. The paint should chip along the score lines.

 

Here's one of the two inline lugs glued in place.

The tab molded into the bottom face of the lug fits into the cut slot.