Rocketarium Hydra Sandhawk Build Part 12, Vent Hole Drilling TIP

1/4" diameter vent holes are drilled in the booster side walls.
The instructions say to drill a 1/8" hole first then enlarge it to 1/4".

TIP: You can make a "drill" out of a 1/4" diameter brass tube.
The inside wall of the tube was filed to a sharp edge using a half round file.

This sharp edge works pretty well to cut a 1/4" hole through the tube wall.

Take an extra moment to center the tube before starting to drill.
Spin the tube until you start to scratch the outside layer. Remove it and check to be sure it is centered. If the circle is positioned correctly, continue the drill.
The tube will want to collapse in so go slowly. It's easier to drill a hole when you can apply some finger pressure on the inside tube wall. You can't reach the inside of the BT-60.
After drilling through the outside continue through the interior BT-50 engine tube wall.

Here's how the tube will look after drilling through both sides of both tubes.
We'll clean up and strengthen the edges in the next post.

Rocketarium Hydra Sandhawk Build Part 11, Booster Mount

I used a dowel to set the glue inside the body tube for the engine mounts.

A line of glue was to be set 2 1/2" from the end. That is the position of the forward ring when the mount is slid in place.

The inset picture shows how I set the glue line just before the forward ring. The dowel was marked just inside of the 2 1/2" mark. This way I know the ring will go through the ring of glue.

For now, glue was only applied for the upper ring.

The mount was slid into position, I used the flat side of my sanding block to be sure the tube ends were even.

The inset picture shows the front end of the booster. The tube ends are even on both sides.

The rear ring got a fillet of glue applied drop by drop on the end of a rounded dowel.
Set a drop in the seam and smooth it out using the rounded dowel end.

Apply more glue drops until the fillet is all the way around the ring joint.

Clean up any excess glue using a Q-Tip.

Rocketarium Hydra Sandhawk Build Part 10, Booster Fin Replacement

Look at the booster fins on this picture shown earlier on the blog.
Those booster fins are very thin.

The fin stock in the kit is 1/8" thick.
That works great for the upper stage  fin taper, but the booster fins would look clumsy.

I wanted to cut new fins from 1/16" thick ply but didn't have any at hand.
I did have some very dense 1/16" thick balsa.

Here's one of the new thinner fins on the right.
It looks larger than the thicker original, but it is the same size.

NARAM Live! Online Coverage

Once again the National Association of Rocketry Annual Meet (NARAM) is online at:
http://www.naramlive.com/naramlive-2013/naramlive/index.html

Thanks to Chris Taylor for setting up the website.

Launch! Schoolyard Soccer Field, July 21, 2013

I didn't go to the Tampa TTRA launch yesterday.
A full day of launching in the Florida Summer heat can be hard to get through.
Another reason for not making the 1 1/2 hour drive, the LPR launchers are in rough shape. There is only four LPR pads, sometimes only two lines are working.
I didn't feel like paying a launch fee and hoping to get a few in the air.
The field is huge and the people are great, just fix the equipment please!
I headed over to the schoolyard a little after 7:00 a.m Sunday morning.

Here's a new one - The FlisKits MMX SATURN V.
This thing is tiny and a challenge to build. It's only 4.75" tall from above the shroud to the escape tower tip. On the bottom is a card stock shroud for stability.
Very stable off the pad, probably got to 60 feet. Whoo-hoo!
The nose section did eject but a melted plastic streamer stayed inside.
Break-apart recovery was still fine, no damage when recovered.

A blog build is upcoming -    

I was hoping to fly the Quest plastic MMX Saturn for a comparison. I couldn't get it over the MMX launch rod, the plastic lug holes were too small! 

This one stays in my range box, loaded and ready to fly.
The Quest VIPER is actually pretty good for a starter kit.
The Quest A6-4 got it up to around 250'.
The spill hole in the chute brought it back close.






Over the last few days I made a CHEROKEE GOON.
1/4 oz. of clay was pressed into the nose cone. This much weight should be good for launching with B6-4s.
The first launch today was with an A8-3 to an estimated 300'.
Full parachute deploy and no damage on recovery.
Sorry, not much of a launch shot!

I've just refinished a beaten HONEST GOON.
This model has been through the wringer, plenty of air time and a test subject for many different clear coats.
Decals were lifted and everything sanded clean.
New decals were drawn up, less were applied this time. The fins got the appropriate black and white treatment.

Launched with a B6-4 it got to an estimated 325' with garbage bag parachute recovery. No damage.



Also flown:
Estes STINGRAY Mk-109 with an A10-3t in a 5/20 adapter.
Not much altitude, still a complete flight to 225'.

Rocketarium Hydra Sandhawk Build Part 9, Sustainer Fin Shaping

From this picture found online you can see the fins wedge shape on the outside edge.
The leading edge looks like a rounded knife edge.

The small booster fins look very thin, much thinner than the 3/32" thick fins in the kit. I might buy some thin plywood to get them to a closer scale profile.

I drew a center line down the leading edge of the fin.
A wedge shape was drawn on the outside edge.

This line was drawn with a fine point Sharpie. The lines were drawn quickly so no ink would soak into the fin. The fins will be painted white and I don't want black ink to bleed through the white paint.

The leading edge taper was sanded first, almost to the center line.
220 grit sandpaper was used on a sanding block.

The leading edge was sanded first then the sides flattened.
Setting the fin surface on the block you can see the convex side that needed to be sanded flat.

Here's the first fin fully tapered.
I marked the root edge with a "M" for "master".
This fin will be used as a "guide" for shaping the other three fins.
Try to match the thickness of the leading edge when shaping the other three.






Next to a untapered fin:
On the left is the root edge, on the right is the outside edge.

Estes Drifter Engine Retention

I went to Jim Z's recently and looked up the old Estes Drifter instructions. The Drifter was introduced in the mid 1960s.
Check out the instructions HERE

For simple motor retention:
I had thought that a simple tape wrap around the end of the engine tube and engine was a fairly new idea.
It's a better method over friction fitting.
I just didn't realize this technique went that far back!