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Vulcan is a custom rocket that I designed to carry my
video
transmitter module for live video downlink. It is 5.5 inches in
diameter and over 8 feet long. It deploys both the transmitter payload module
and its own recovery parachute at apogee. The transmitter and the rocket
come down separately. Vulcan has a 75mm motor mount that will
accommodate up to an M1315 motor. The airframe is flexible phenolic with
two layers of 6 oz fiberglass. The centering rings are cut from 0.5-inch
aircraft plywood.
Click here to view
launch photos of Vulcan.
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Length: |
8 feet, 8
inches |
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Diameter: |
5.5 inches |
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Weight: |
38 pounds with
M1315 motor and video payload |
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Motor: |
75mm mount
accommodates up to M1315 motor. (Aerotech 6400 NS case) |
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Altimeters: |
2 each,
Missile Works RRC2 |
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Locator: |
Walston radio
transmitter |
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Payload: |
CCD video
camera, 1.3GHz transmitter, GPS info overlay |
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Parachute: |
Rocketman R14
on rocket, Rocketman R12 on payload module |
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Built: |
Jan. - Mar.
2001 |
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First Flight: |
April 28, 2001
on K700 at Crater Rings launch site near Mountain Home Idaho |
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Construction: |
Body tube:
flexible phenolic + 2 layers of 6 oz fiberglass
Fins: G10 fiberglass
Nose cone: plastic
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Results are for L850 motor plus video transmitter payload.
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| Motor: L850W |
| Maximum altitude: 5908 feet |
| Maximum velocity: 426 MPH |
| Maximum acceleration: 6.8 g's |
| Time to burnout: 4.7 sec. |
| Time to apogee: 19.8 sec.
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| Launch guide length: 96 in.
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| Velocity at launch guide departure:
38 MPH |
| The launch guide was cleared at:
0.35 sec |
| Liftoff weight: 35.1 lbs |
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The altimeter bay in Vulcan contains two
Missile Works RRC2
altimeters. Each is completely independent of the other in order to
provide redundancy for improved reliability. In addition, each altimeter is
configured for redundant deployment at apogee. This means each altimeter
can ignite two separate ejection charges. There are two black powder
ejection charge holders inside Vulcan. Each altimeter is connected to
each BP charge. This means a total of four ejection charge igniters are
used on each flight. Vulcan requires 4.5 grams of BP in each holder.
The primary circuit on each altimeter is wired to the same ejection charge
holder. Likewise the secondary (or backup) circuits from each altimeter
are wired to the same ejection charge holder. This avoids the
possibility of having both charges go off simultaneously.
The ejection charge holders in Vulcan are simply
3/4-inch PVC pipe end caps mounted to the bulkhead that closes off the
altimeter bay. The igniter wires also go through a small PVC fitting in
that same bulkhead. The inside of the small fitting is filled with clay
to seal the wires off so that ejection charge gases can not reach the
altimeters themselves.
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The nose is a standard injection molded
plastic cone. I used the PNC-5.38L available from
Magnum. |
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Vulcan fins are cut from 0.125-inch thick G10
material. A carbide jig saw blade was used to cut them. |
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These two photos show the
fins as they were aligned and held in place prior to adding the
forward centering ring to them. |
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The photos above show the
four fins being held in place and being attached to the forward and aft
centering rings. Since there are four fins at 90 degree angles, I
simply used some scrap pieces of 1x2 that I clamped to the surface of each
fin with the "Quick Grip" clamps you see in the photos above. A tee
square was used to make sure both sets of fins were perpendicular to each
other. There are small angle brackets attached to the top and bottom
of each fin. Screws were used to attach these angle brackets to the
centering rings. Once this was done, the motor tube was slid down
the middle of the fin set and everything was then locked in place
with generous amounts of epoxy. |
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This shows the fin set after
the motor tube was added and everything had been epoxied in place. You
can also see the addition of a small block of wood on top of the upper
centering ring. This small block contains a threaded brass insert that
is the mount point for the upper launch rail guide button. There is
another brass insert in the aft centering ring for the lower guide button.
These inserts allow the use of a machine screw for mounting the rail guides.
(They also have a much higher pull-out force than do wood screws into the
edge of a plywood centering ring.) |
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This photo shows that the
body tube as been slotted and added to the fin section. Blue tape is
at the end of each fin root to act as a dam for holding epoxy in place.
The fin fillets are formed by simply pouring epoxy into the joint and
letting gravity level it. Once the epoxy cures, the blue tape is
removed and a Dremel tool is used to touch-up and form the ends of the
fillets. |
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