Semroc IRIS Build Part 21 Oops!

This is what can happen when you take pictures for a blog by yourself. I dropped it!

The IRIS fell hard and broke off two fins. The fin on the left has a pretty good ding in the trailing edge.
Sure, it's all repairable.



I used CWF (without thinning it with water) right out of the tub.
For filling a corner ding like this, the CWF dries much harder and sticks better when used full strength.
A razor blade was used to apply and "trowel" off the filler.
The filler was left wider than the fin thickness so it could be sanded to the flat surfaces of the fin.





After the filler dried, it was sanded down and level with the rest of the fin surfaces.

Semroc IRIS Build Part 20 Fin Mask and Gluing

All four fins have been sprayed red. The root edge on the left still has the thin masking tape strip in place.
On the right, the tape has been removed.

I used a sanding block over the root edge to remove the paint "step" and to take off most of the red down to the bare wood.





A thin strip of Monokote Trim was removed for the root edge gluing.







Using the "double glue" method, the fins were glued in place.
I'm going back and adding some thin CA glue with a toothpick tip. The glue will be set at the rear of the root edge and under the fin tabs with the hope it will run underneath and reinforce the joint.



NOTE: Gluing the fins on after painting doesn't make for the strongest bond! Gluing bare balsa to a bare tube and fillets before painting is much stronger. But, taking into consideration the color separations on the body tube and the fin tabs getting in the way, this seemed to be the way to go.

Estes A8-3 Burn Through

After the July 18 launch, I was removing the Estes A8-3 engine from my Squatty Body. Here's what the casing looked like.
To the right (nozzle) side you can see lots of charring and what looks like a hole.



I made a long cut down the length of the casing and unrolled the paper.
It's clearly a burn through.

I've seen this happen in monocopters with Quest Chinese made engines.
This is very unusual on an Estes engine.




Here's the inside of the engine mount showing the burn through hole. It didn't go through the outside body tube so it'll be okay for more flying.

NOTE: Never cut into a live, unused engine!
This expended (used) engine posed no danger when opened up for post-flight analysis.

LAUNCH! Schoolyard July 18, 2011

7:30 a.m., Soccer field - no wind!

Perfect conditions for the Odd'l Rockets CYCLONE with a 1/2A3-2t engine.

Straight boost to 375' with a little whistle heard from the air passing by the porthole. Clean separation at ejection. The upper single blade spins very fast as it almost hovers, both sections landed close to the launcher.





The FlisKits HONEST JOHN flew flawlessly to 125' with a MicroMaxx engine.

It was followed up by the 13mm Odd'l Rockets UP! CUP with a A10-3t engine. Clean flights from both birds.






My original prototype of the Odd'l Rockets SQUATTY BODY was launched with an Estes A8-3 engine. After dozens of flights, this one is showing a few scars.




Normally I wouldn't launch a B6-4 on the soccer field, but it's a perfect match in the Semroc CENTURION. Altitude was around 325'.
With one of the two 12" parachutes removed it still lands easy enough on the low cut grass.

This was one of those launch days when everything worked as planned.
All were recovered with no dings or repairs needed.

Semroc IRIS Build Part 19 Rear Color and Lugs

I used some aluminum Monokote trim material for the silver area behind the rear band. I used aluminum because the silver Monokote looked a little too metallic and shiny.

The lower launch lug was wrapped with the same trim material. I didn't wrap it all the way around, but left a narrow open strip of exposed lug for gluing.

A small rectangle was cut away for the lug to sit in. the lug was glued in place with wood glue.

The upper lug was painted white and glued to a masked rectangle on the upper body. Both lugs were lines up using a 18" length of launch rod.

Semroc IRIS Build Part 18 Color Separations

The tube is marked halfway between the upper and lower bands, around 7 1/2" from the top.

I wrapped card stock around the tube for an edge to cut against.
Use a sharp knife and cut carefully. The paint will chip off if cut to quickly.

Use a sanding block with 400 grit sandpaper to clean and square up the edge. The coupler is already inserted for support of the edge when sanding.

Remember the coupler from Parts 6 and 7?
Join the two cut halves together.

Turn the upper tube 90 degrees - Voila!



If you took the extra time to make sure the tube was masked evenly, you should have a clean separation with the corners matching up. Nobody will notice the cut tube, the sharp color breaks will hide the line.

Semroc IRIS Build Part 17 Color Separations

It's hard to see in this picture, but Scotch tape was used over the white area separation lines.
Masking tape covered the area between the thinner Scotch tape lines.





Here, the Scotch tape is removed. The mask line is looking clean so far.





With all the tape removed, here's where the tube stands now, four long bands. Two white and two in black.

Note, the fin root edge and launch lug gluing lines were masked for better adhesion on the body tube.