Removable Altimeter Bay

Hi there,

I have an idea on a removable altimeter bay, along the lines of the Smokin Rockets Altitube, but I need some additional advice.

I have a PML Mini BBX that I want to modify for dual deployment. I have an Altacc. I have some extra parts lying around...

My plan is to have a coupler that is glued to the upper section of the BBX (the lower section is fastened on this coupler with screws, so one can take it off to exchange the altimeter, refill ejection charges and the like). This coupler has two bulkheads to which the shock cords leading to the pistons are attached. Also, there are (or rather will be) holes in the bulkheads to accomodate a 38 mm tube with bulkheads to slide in. This tube includes the altimeter, holds ejection canisters and whatever you need. Now I need a way to secure this 38 mm tube in this coupler or on the outer bulkheads... Any ideas?

Oliver

PML (I think) offers plastic rivets that are removable for just such a purpose.
Other than that, there's the possibility of drilling (mating) radial holes in the airframe and coupler for the application of teensy weensy screws to hold everything together.

I have had good success mounting thread-inserts into the altimeter bay and then using screws. No so tinsy-winsy either.

You can see how I have done it and also a link to how Missile Works recommended it on my Descon 9 entry.

I also outline the differences that I made from the Missile Works version. I made it stronger.

The mount involves wooden dowels glued to the inside of the altimeter bay. The inserts go into the dowels and the screws are then through the airframe into the altimeter bay.

Most of the information is on this page: HERE

For a diagram and the starting page of the whole rocket go: HERE

EMRR, that is the coolest design I have seen in a long time. Great work. MarkBrown and I had talked about a design like the Estes DC Gemini where the two side tubes are external of the main airframe. End result is 3 engines, 3 nosecones, one chute in the main and a removable altimeter. It would look similar to what you have in the Big Blue Dog. Isn't this sport/hobby fun???

BTW: I don't think the paint job looks bad at all....

Hi there,

I guess I finally found a way to build an exchangeable altimeter bay (mounting as in PML 2.1" QT airframe, e.g. Mini BBX, Phobos).

<img src="https://www.shuttle-endeavour.de/webimg/altibay_eng.jpg">

I have a standard length coupler glued halfway into the airframe. It has bulkheads with 38 mm holes and two threaded rods on each end (as seen on the front). There is the 38 mm electronics tube (with the Altacc shown inside), which has bulkheads on each end too, onto which are mounted the ej chg canister (not shown). One of the bulkheads just sits in/on the tube, as it has to be removable to change the battery on the Altacc. This tube is slid into the coupler and secured by washers nutted down onto the rods on both ends (on the not shown end, the washers are permanently fastened, since I only have to change the Altacc from one end - the washers might be replaced by a wooden ring, that will just let the ej chg canister slide through).
The other half of the airframe is secured on the coupler by screws.

Any further improvements greatly appreciated.

Oliver