Saturday, August 23, 2014

Carded Downscale Black Brant VB - Part 6 Laminated Fins B


Before cutting, study the fin at the right.

Look for the small dashed lines near the middle. After folding this will be the rounded leading edge.

Note the upper side of the fin is slightly larger than the lower side. This is to insure full red ink coverage on the larger side after the fin is cut out.

After folding and gluing the fin will be cut out through all three layers on the ROOT EDGE side.


First, score the dashed line using something blunt like the tip of the butter knife shown in the inset picture.

Use a straightedge and not much pressure to score a line down the middle using the dashed lines as an end point.
It is important that the embossed fold goes right down the dashed lines.

Cut out the fins outside of the edges.









First fold gently by hand then use your burnished to make a sharper crease down the embossed line.
This fold doesn't have to be razor sharp!
It should end up being a rounded edge.

Parachute Descent Rate Calculators




On TRF, sooner.boomer posted the question:
Parachute-How Big, Too Big?
How can I find the minimum weight for a given diameter chute (assuming a spherical chute)? 

Race58 gave these links:
By Jordan Hiller
http://www.rocketreviews.com/descent-rate-calculator.html
By Jordan Hiller
http://www.onlinetesting.net/cgi-bin/descent3.3.cgi
By Randy Culp
http://www.rocketmime.com/rockets/descent.html

Friday, August 22, 2014

Carded Downscale Black Brant VB - Part 5 Laminated Fins A

I've written about the cereal box laminated fins before.
If you haven't made fins from a card stock laminate you might be surprised how strong they are.

These fins are actually a triple thickness of:
1. Printed 100 lb. card stock (one side)
2. Cereal Box cardboard
3. Printed 100 lb. card stock (the other side)

The outside printed layers of 110 lb. card stock are "butterflied" and fold over the cereal box cardboard at the leading edge.
If folded and glued correctly, this makes a rounded leading edge on the finished fin.
Trust me, it's easier to do than read through the description.

You'll need :
The fins printed on 110 lb. card stock, 220 grit sandpaper, cereal box cardboard (this is from a Cheerios box), glue stick, straightedge and a sharp hobby knife.

First, rough up the printed side of the cereal box cardboard with 220 grit sandpaper.
It won't take much, just remove some of the gloss and ink.
The glued outside layers will stick better if some of the ink is removed.

This sanded ink and fine dust can get everywhere! Dust off the cardboard and wash your hands before gluing anything.


You will need a straight long cut to be the inside leading edge of the ply fins.
With  sharp knife and straightedge, cut off the crooked edge down a long side of the cereal box board.



For a rounded leading edge, lightly sand the the square cut you just made with 400 grit.
Don't over sand it, just knock the corners off the edge.

NARCON LPR Construction Video

From last March, my NARCON session on LPR Construction and Tips is on the  www.narcon.org website. CLICK HERE
Other sessions are being added.

Many of the techniques from the blog are on the video.
It's always weird to hear yourself talk.
Note to self: Don't slump.

Thursday, August 21, 2014

Carded Downscale Black Brant VB - Part 4, Body Tube Trim




The edges of the Estes plastic nose cone are too square and could turn the interior body tube edges in.
A simple rounding of the base edges gave an better slip fit.



The BT-5 tube was longer than the wraps.
Both ends of the tube were trimmed down, just above the printed wrap ends. The nose cone was slipped into the tubes for support when cutting.
The remaining white tube was sanded down to the wrap ends.



I know, stick to the subject -   
With the nose cone inserted in the bottom, the tube makes a good single note Pan Flute.
The 7" BT-5 tube plays clear, close to an F#.

Try this next time you have to entertain the grand kids. They'll think you're a genius.

Plywood, Chicken Wire and Fiberglass Mercury Capsule

I went with my daughter Whitney and her boyfriend Paul to the Orlando History Center Museum on Sunday August 17. My daughter is a big fan of "Gone With The Wind". They had the touring display of movie props.

On the first floor was a small NASA space program display.
Along with plastic models of manned space vehicles there is a Mercury capsule. I had to get inside of it. The plaque states:
"This is a recreation of the actual Mercury capsule. It is constructed of plywood, chicken wire and fiberglass and is approximately 98% scale of the actual Freedom 7."

Only 98% scale? I thought the fit was a little tight.
Inside the capsule is a small TV screen where you can actually play Space Invaders.
Just like the real thing!

Wednesday, August 20, 2014

Carded Downscale Black Brant VB - Part 3, Launch Lug Wrap



Cut out the lug wrap and do a pre-curl in the heel of your hand.
Use a small dowel or the shaft of a Q-tip.

Apply a coat of glue stick to the inside surface.
The lug is small and you can start the wrap from the center working out.

I set the lug in the middle of the wrap an rolled the sides to the top.
This lug is purposely longer than the wrap and will be sanded to the to and bottom of the wrap.

By the time I got to the other side the glue had started to set up. Another rub of glue stick and the wrap was finished.

The top and botttom of the lug were sanded to the length of the wrap with 400 grit on a block.
On the left you can see some of the lug edge rolling into the middle.
Pick out and raise the edge over the top of the lug. Raise about 1/3 of the turned under edge and sand off.
Turn the lug 1/3 turn and raised the next third inside edge. Sand that off.
Work your way around the inside of the lug until all the edges are removed.

Compare the lower picture with the upper lug and you can see the rolled over edge is gone.
A turned under lug edge might get caught on a launch rod or slow down the boost speed. It should be cleaned off.

The inset picture shows the wrap seam. Like the body tube wrap the edges are almost invisible.
This lug wrap seam will be turned into the fin fillet area.