| Dennis Brooks converts Delta 7 Models into flying rockets. Ever
since we first published these photos we've been hearing from others who
are making their Delta 7 models fly. Below is Dennis' letter describing
how he did it. If you have a different way of converting your rockets,
write and tell us about it.
 
 
Hello Dan,
The first step is to strengthen the paper. I use Smith and
Company Penetrating epoxy to soak the sheets after printing. The
ink does not run, but the epoxy fills the voids in the paper while
allowing it to remain pliable. I have used it on my R/C boats for
some time to avoid dry rot and strengthen the hulls.
I build the model pretty much per the instructions, but as I
build I add a few Estes components and hardware. After rolling the
body tube, I cut a used A-C Estes motor down by about a third,
cutting off the clay nozzle. The remaining 2/3rds becomes the motor
mount for the 1/4 A10-3 motors I use to launch the rocket. You may
need to wrap the motor in one or two layers of paper to get a tight
fit gluing it in to the rocket tube level with the bottom edge. You
do not need an engine hook, the old method of friction fitting the
smaller motors into the used casing works fine. If the live motor
is a little small, you put on a small piece of masking tape to lock
it in tight enough not to blow out during ejection. Attach the fins
as shown, then place a launch lug from Estes, parallel to the body
between two fins with the center of the lug 3 inches up from the
bottom of the rocket. Attach with yellow wood glue for strength.
I put clay weight in the capsule to weight the nose and
allow me to screw in an eye bolt to attach the shock cord. A little
two part epoxy flowed into the capsule after adding the clay as you
seal the heat shield give you the strength needed and holds
everything in place. I added a 3/8ths inch skirt to the bottom of
the capsule that fit snugly into the top of the body tube. This
holds the capsule/nose cone in place during launch.
I use 16 to 18 inches of elastic cord from a sewing shop to
form a shock cord between the capsule and the top of the rocket. You
cut a tall trapezoid of paper, fold and glue with yellow wood glue,
down twice with the cord laid in the center. The folds lock the
cord in place. While still damp use the same yellow glue to attach
the folded paper and cord to the inside of the rocket body tube top
about 3/4ths inch in. You form the damp paper to the tube for a
tight seal and good adhesion. While this is drying you cut a
parachute.
I cut mine from heavy plastic clothing store bags. I used a
6 sided 9 inch across piece for this small rocket. Button hole
twist thread, from the sewing shop, is find for the shroud lines
(from the parachute to the shock cord). I cut three 18 inch cords
and attach each to two adjoining corners of the chute. This leaves
three loops. To attach the corners, place paper reinforcements,
disks or washer style on the corners. Push a sharp pencil point
through for a hole big enough for the thread. Tie each corner with
approximately the same length of thread to keep the loops the same
length. You can glue over the knots to seal and prevent
unraveling. I like to use small fishing swivel clips to attach my
chutes. They allow the chute to spin and not wrap up the shroud
lines. Holding the centers of the three loops together, you feed
them through the eye on the swivel, pull through enough to form a
loop and push the parachute through. As you hold the swivel and
pull the top of the chute, the lines will tighten and slide down to
the swivel locking it at the center point of the shroud loops.
Again, you can glue over to prevent slipping or loosening.
Tie the free end of the shock cord to the capsule eyebolt.
Then form an overhand knot in the shock cord about 1/3 down from the
capsule to the rocket body. Clip the fishing swivel through the
knot and pull the knot tight. You can put a small 3/4 inch hole in
the top of the chute to allow air to escape and prevent the
"rocking" back and forth that normally occurs when a flat chute
spills air as it comes down. The swivel is not necessary, you can
tie the center of the loops directly to the shock cord, this just
helps stabilize during decent and protect the fins on landing.
Once all are dry, put two to three sheets of flame proof
wadding down in the rocket body. Coat the plastic chute with baby
power to prevent static cling and friction burns. Pull it from the
top of the chute, holding the rocket body. This will "spike" the
chute forming a thin bundle. Lay it on a flat surface. Fold the
top of the chute to the middle, the fold again to the bottom. Keep
the bundle tight as you fold so it will fit into the rocket body.
Wrap around the folded bundle with the shroud lines then insert the
shock cord, wrapped chute and cap with the capsule/nose cone.
Insert a 1/4A10-3 engine and arm per package instructions. Using an
Estes launcher or rod into a wood block with a paint can heat
shield, slide the rocket into place on the rod. I use masking tape
on the rod to hold the rocket 3 to 4 inches above the pad heat
shield. This prevents blow back during launch from scorching the
bottom of the rocket. Just take a piece of masking tape about 3
inches long. Fold it over the rod forming a 1.5 inch flat piece
sticking out from the rod. This prevents the launch lug from
sliding over the tape and binding.
Use an Estes launch controller, or a 17 foot double wire with
alligator clips on one end and a square 9 volt battery for power.
If you use the battery, push one wire through the fingers of the
spit pole. Cover the other pole with a flap of tape or similar.
When ready to launch, touch the second wire to the solid pole and
you are in business.
The rocket will fly up to about 250 feet. The ejection
charge fires and the rocket comes back under parachute ready for
another launch. Illustrations for the parachute, lines, shock cord
and attachment can be found in any Estes kit that attaches the shock
cord to the body tube with paper. This is just a scaled down
version. You could use a 1/4A10-3 Estes engine mount, I just had
the used motor cases handy.
These are pretty much the steps. Some model rocket
experience is desired when converting or building from scratch. Any
Estes kit with similar components will help with the diagrams. I
can provide more photos if you like. Let me know what you don't
understand and I will add as necessary to clarify.
Dennis
Brooks
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