Look at LOC Precisions site. They do an avionics bay for 3" & 4" kits. I
know that's not the size you want, but there is a very good diagram of how
is constructed which may help you out in making a well designed bay from
I have had good luck creating a 2 inch bay from the LOC 54/38 mm motor mount
adapter. I glue the thrust ring to the middle of the coupler tube. Epoxy
both of the centering rings an 1/8 inch deep into each end of the coupler
tube. Discard the motor tube to the spare parts bin and purchase 2 couple
bulk plates to use as end caps....drill then for 1/8 inch all thread and
voila....2 inch electronics bay.
If your interested I have some photos of a 54mm ebay I did on my Phobos.
Extremely simple design and very functional. Send me a line at tdstr
at visi dot com and I'll dig them up.
Email Giant Leap Rocketry. I have their 4 inch version and it is
first class. I'm sure they can provide the pieces to do a 2 inch
John<==the 1/4 inch all thread may be a little oversized, though
I put together a 2.25" diameter electronics bay. You can
view the results / example pictures here:
XAVIEN and U.S. Rockets are currently putting together a kit for the
smaller diameter series.
Good luck, let me know if you have any questions.
* XAVIEN *
Phoenix, Az USA
Building an altimeter bay is easy. I have built my particular version in
sizes from 2" to 6" diameter with no troubles.
2 ea. bulkheads sized for couplers
Cut a length of coupler to at least twice the diameter of the airframe.
For a 2" airframe this is at least 4". The length of your altimeter will
determine the required length in this case. The interior needs to be
long enough for the altimeter and provide clearance for the hardware in
Cut another length of coupler that is the same length minus the
thickness of the two bulkheads. Slit it lengthwise and remove a slice of
material sufficient to let it slide into the first coupler.
Slide it into the first coupler and test fit the bulkheads. Make any
adjustments required. Now remove the bulkheads and use CA on the inner
coupler to keep it in place.
Now epoxy in one of the bulkheads. You probably want to install the U or
eye-bolt first. Be sure to use a little Loc-tite or equivalent on the nut.
Now drill the bulkhead and install one or more pieces of threaded rod
that run the full length of the coupler to the other bulkhead.
Fill out the other details such as altimeter mounting, holes for wires,
U-bolts, and you are done.
Because I typically use an AltAcc, I do a slight variation on this. The
AltAcc is designed to bolt to the inside of the airframe. Rather than
add extra unsightly bolt heads on the outside, I put them inside. Before
gluing the two coupler pieces together, I first drill the altimeter
mounting holes. The inner coupler has small holes for the machine screws
and the outer coupler has holes larger enough for the screw heads. PML
coupler is typically thick enough that the screw heads do not interfere
with sliding into the airframe. If they do, a little work with a file
solves that problem.
To make sure everything lines up the way I want, I start by fitting the
coupler into the body tube where I want it. Then I drill the arming and
LED holes through the body tube and coupler. Now I measure the mounting
holes in the coupler from these holes.
To prevent mixups in the field, I install a wire harness with a
polarized connector on the altimeter and in the altimeter bay. This
makes it easy to install the altimeter and I don't have to worry about
mixing up drogue and main. Which happens more often that you would think.
Altimeter bays are as simple or complicated as you care to make them.
David W. Schultz
If you cannot get a long enough piece of coupler tubing, take 3 couplers and
slit one of them to use as an internal splice for the other two. If it
will be a coupler bay between the booster and payload bays, glue a short
length of body tube over the splice as well. Add bulkheads, etc. just like
the fatter bays. Not all units will fit in a bay like this, but most of
the smaller ones will.
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