Nike Goon Build, Part 2, Scaling to a BT-60

I found this picture at RocketReviews.com, from a build and review by Matthew Bond.
This is the Goony version designed and produced by Excelsior Rocketry.

I didn't have the Excelsior plan/decal set and I'm not trying to make an exact copy of the Excelsior model. There are a few Baby Bertha kits in the build pile and I wanted to make something different from them.

I dropped the Estes picture into Corel Draw, the original is on the left.
That was stretched to the diameter of a BT-60 at 1.637" wide. The stretched version is shown on the right.
Some adjustments were made. When stretched to the BT-60 width the fins were too wide.

Drawing it this way makes it closer to the Estes kit profile even though it is now wider and shorter.





A line tracing was made and copied to a new page. This gives a pretty clean representation of how the Goony version will look.

AVI Nike Tomahawk Build Part 3 Scratch Coupler

You'll want to sand the coupler to have a tight slip fit into the 35mm tube, so make the second cut slightly oversize.

The short mark on the left was the overlap mark when it was in the 35mm tube.
The long line is the oversize cut line.

Cut on the long oversize line and test the fit.




Chances are the coupler will need some sanding until you get the tight fit you want.

This picture shows a good fit with both edges of the coupler tight against each other.

Cut a glue tab from some scrap tube.
I cut mine just inside the 1" length of the coupler.
It's just over 7/8" long x 3/8" wide.

Glue 1/2 of the tab inside the coupler edge. Let dry.

It's hard to see in the picture but the other side of the glued tab is being pressed inside the coupler.

Turn the coupler to be sure it doesn't get glued into the tube.
When the tab is pressed in place excess glue might be pressed out of the coupler seam.

AVI Nike Tomahawk Build Part 2 Scratch Coupler

Good luck trying to find a 35mm coupler! It'll be made from a 1" long piece of 35mm tube.

I'll be joining a 20mm tube to a 35mm tube.
The center circle pencil line was simply a trace around a 20mm tube.
The center was marked.
The outside ring was drawn with a compass to a diameter of 1.5"

To get a tight fit around the 20mm tube, cut just inside of the the pencil line you traced around the 20mm tube.
We'll come back to the centering rings after the coupler is made.

A 1" length of 35mm tube will be used for the coupler.
Two wraps of masking tape were set at the 1" mark to give an edge to cut against.

Use a sharp knife and a few passes around the tube to cut all the way through.
The Quest 35mm tubes are thick and didn't need any support on the inside while cutting.

Square up the cut ends on a sanding block.

Mark a line straight down the length of the tube.

Cut down and through the tube using a straightedge.

Let the tube overlap itself and slide into the 35mm lower body tube.

Press the cut coupler piece tight against the inside of the 35mm tube.
Mark the overlap with a sharp pencil.

Remove the cut coupler.

AVI Nike Tomahawk Build Part 1 Scale Factor

This is one I'd wanted to build ever since I received the AVI catalog in 1973 -
The NIKE TOMAHAWK
Check out the AVI catalog here:
http://www.ninfinger.org/rockets/nostalgia/73avicat.html

I don't think many of the kits in the catalog ever made it to the hobby stores.
A few of the AVI engines have been shown on the forums.

This was a kit made up from two older MPC kits, the Tomahawk and the Nike Smoke.
The Tomahawk was 20mm tube based, the Nike Smoke was a 35 mm tube.
Quest sold both the plastic fin cans up until July of this year, I ordered three.
The plastic transition doesn't exist - it'll have to be made from card stock shrouds.

The model is based on the Peter Alway drawings from Rockets of the World, 3rd edition. You can find it on page 161.

Before I show the parts, the adapter will have to be made.

The scale factor (based on the 35mm tube at 1.378" diameter) is 11.93.

To get the scale factor, the diameter of the Nike Booster body (16.44") was divided by the 35mm body tube (1.378") The result was a scale factor of 11.93.

All the dimensions in the Alway drawings were divided by the 11.93 to get the model dimensions. 

On the left side are the real dimensions in inches. On the right are the model dimensions.

The 20mm tube is a bit off. 9.0" (real Tomahawk diameter) divided by 11.93 = .754" model diameter.

The 20mm tube is .787", close enough for sport scale.

The adapter will need two rings 1.5" wide. They are cut from mat board and two will be glued back to back for the wider center piece between the two shrouds.

Before showing all the parts, I'll need to clean up what I have and make the adapter.
This adapter assembly will take up a few posts!

Minin Honest John Build Part 15 Scale Factor for Masking

The real M-50 Honest John diameter is 23".
The model diameter is a BT-50 at .976"

23" divided by .976" = a scaling factor of 23.56

All the measurements on the Peter Alway drawings will be divided by the scaling factor of 23.56

Instead of painting the model an overall Olive Drab, I decided to paint it in the test round pattern shown in the lower right of the Alway drawing.

The tip of the real HoJo is light grey down to 32.41".
Divide 32.41" by the scaling factor of 23.56 and the grey on the model will go to
1.37" down from the tip.

I divided the scaling factor into the other nose cone masks and came up with the measurements shown in the picture.