On the right, the mount is flipped over. The upper end of the engine hook is in place. A line of glue is set down for the upper centering ring.
Note the upper ring is not even with the end of the engine tube. Setting it below the edge a bit allows for a glue fillet on both sides of the ring.
To be sure the vane crescents are smooth, they were set down on a piece of masking tape for a spray of gloss white.
The sides were lightly sanded with 400 grit.
I had originally built four Antar models, this picture shows two of the lower centering rings.
The vane tabs were sanded at a slight angle to slide into the centering ring slots.
This is a dry fit of the vanes. Notice the vane on the right side.
The vertical inside edge is even with the interior circle. The outside overhangs the the outside edge.
When the mount is slid into the main airframe tube, the overhanging corner of the vanes will stop and position the mount even with the end of the tube.
Chris - hard to tell from the pictures but would it be possible to go up to a 24mm motor tube by opening up the existing centering rings and trimming the “vanes”? Those vanes are such nice detail be a shame to lose them.
ReplyDeleteHi Openroad,
DeleteAs I understand it - The original G. Harry Stine design had a hole drilled in the engine location that was right about 18mm. Maybe Bill Stine wanted that in the Estes kit design for historic reasons.
You could probably go with a 24mm engine mount but it would involve cutting up the vanes and changing the engine end profile.
You would also have to consider more nose weight, there is already 1/2 oz. of clay in the nose cone for the 18mm version.
I'd probably play it safe and go with an 18mm D composite motor. But - If you change the design, stability is in your hands, not by any recommendation from me!
Great point - I didn’t think about using QJets, easy to get stuck in “old school” mode, using a D20W is a lot simpler than modding the motor mount! Even sticking to Estes C11s would mean adding over 1/4 oz more nose weight - using full-length 24mm motors might mean an additional ounce or more - QJets are a better way.
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