This may look like a standard build but we will be covering:
Making your own centering rings from card stock and cereal box cardboard
Making a "close" clone from a internet photograph
The Odd'l Rockets XLEH E X tended L ength E ngine H ooks
I know that most modelers would "clone" ...
Please note: This model is designed, owned and Copyright by Quest Aerospace. I would hope you would buy the Quest kit or parts to make your own. I am only using it as an example of how to make a "near clone" using just the picture from the website. This'll be a little hard to describe - I'll do my ...
Because it is so new, the Cobalt instructions or fin patterns are not available online.
We'll do the best we can from the picture on the Quest website.
The Cobalt image was copied and imported into my Corel Draw Software.
The image was rotated to vertical.
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The XLEH Extended Length Engine Hook is 3" long. By gluing the engine block BELOW the upper bend of the hook, there is no chance of tearing the motor mount tube if you have a strong ejection. The engine is effectively locked in place. With a strong ejection, the engine is kicked backwards pulling ...
When using the Odd'l Rockets EXEH , the engine block (or thrust ring) goes under the top bend of the 3" long hook.
You do have to use a 1/4" long engine block . The EXEH hook is 3" long. With a 1/4" engine block ring below the upper bend of the hook, that leaves 2 3/4" for a standard ...
I made some centering rings from Cereal Box ply. I always have some on hand for rings and fins. This thick white stock was made three ply from: 1. 110 lb. card stock glued over 2. Cereal Box card stock glued over 3. 110 Lb. card stock Lay on some glue, smooth it out, lay the ply and let dry in a ...
Cut the centers out first.
Use a SHARP knife, this homemade card stock is thick!
Note that I cut INSIDE the drawn line. This is because you traced around the outside of the motor mount tube and the drawn diameter is too big for a good fit.
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The Quest nose cones are inexpensive. They are also not perfect.
After you sand down the convex raised seam you'll still have some concave areas. Carpenter's Wood Filler will not stay in this shallow groove.
Lay a ...
If you ever fly the Cobalt with anything more powerful than a Quest A6-4, you'll want to open up the hole in the back of the nose cone shoulder to install clay weight.
Start widening the hole with ...
I'm slowly adopting a new way to fill the body tube seams with thinned Carpenter's Wood Filler.
I now dip the tip of a hobby knife into the tube of thinned CWF.
A small drop is left on the knife tip.
The blade is set into the seam and the drop is dragged ...
This is a technique suggested in a TRF post by Todd (Bradycros on TRF)
The filler will be "locked" into the seam with thin super glue.
I set a drop of CYA on a scrap piece of card stock. In the picture I used the backside of some old sandpaper.
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The exposed end of the engine mount will be painted black.
This picture isn't of the engine mount slid into the body tube, that's paper taped around the centering ring for masking. The tape is over the centering ring edge.
I slid a used engine casing into the rear ...
Some instructions tell you to extend the fin marking lines downthe entire length of the body tube.
I used the root edge of the fin as a guide for how long to make the line.
I'll make the line a little longer than the root edge length.
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Using the pencil line as a guide, lightly sand to rough up the surface for better glue adhesion.
Notice I left a little bit of the mark at the top to draw the line again.
Using that remaining tick mark and your aluminum ...
After the fins are in place and the glue is dried, erase as much of the forward pencil alignment line as you can. You won't be able to erase it if there is any dried glue on the line.
The Cobalt clone is ready for white undercoats, followed by the overall blue ...
After the blue had thoroughly dried, I started masking for the two silver fins. While many use expensive, specialty masking tapes, I get great results using regular clear Scotch tape for color separations.
It's not hard to mask down a straight root edge, but I wanted the ...
The rest of the rocket is covered with pieces of a cut up plastic grocery bag.
You can see where masking tape was to the side of the Scotch tape already in place.
The nose cone has been removed and the bag ends are tucked into the top of the body tube. ...
After spraying the silver on two opposing fins, the model is left to dry.
Never touch a fin to see if it is dry! If you have to check, touch some paint on a covered masked area to check it.
TIP: In the picture, notice how I pull the ...
Now that the body paint is finished, the engine mount is glued in place.
Because the body tube is so short, I'll set the mount in the tube dry and add glue afterwards.
This'll give me the chance align the engine hook centered between two fins.
I went ahead ...
Here's how the streamer was attached to the shock cord. The streamer is only 1" wide.
Usually the snap swivel would be flipped around when using a parachute. But on this model, there will never be enough room for a parachute. I used the swivel this way so when I ...
Last year I built a clone of the new Quest Cobalt kit. I know - Why build a clone of a available kit? A few reasons: 1. I had extra Quest PNC40 nose cones and 40mm body tubing at hand. 2. I wanted a good schoolyard rocket for all the A6-4 engines I'd bought. 3. I'm cheap. I did my best to clone ...
