Altimeter inside an Estes Executioner nose cone

[4regt4]

I acquired via an ebay auction several Alt15K/WD altimeters. They have minimal protection, and are intended to be anchored down to something, not just left flopping around like you would do with an Estes altimeter (for example). For my rockets with a payload section, I wrap them in foam. Works fine. They are nearly the same diameter and length as my index finger and fairly light.

But the Executioner doesn't have a payload section. However it has a big nose cone. I'm thinking of installing a BT-20 tube inside the nose cone, but not sure how to hold it (and the altimeter) in place. I know some people install bulkheads, etc., but I'm looking for something quick, easy, and light. I don't have the tools to fabricate anything with reasonable precision. And the bulkhead route would be overkill for a $15 altimeter that may not last long anyway. If I cut a hole in the base of the nose cone, I would lose the molded on plastic loop that the shock cord is attached to unless I offset it a bit. (I also have a small loop of Kevlar going through little holes in the nose cone base in case the plastic loop breaks.) Any idea I've come up with makes access to the altimeter difficult. I have to remove it to turn it on, install it, and then remove it after flight to hook up to my laptop.

I'm currently using a Firefly on a tether wrapped in foam in this rocket, but I'd like to utilize the data logging capabilities of the Alt15K, and there is a generous amount of room in the Executioner nose cone if I find a simple way to use it.

Hans,

 

[BEC]

Put a piece of BT-20 in offset as you suggest. Since there's no accelerometer in the that altimeter, the angle/orientation really doesn't matter. Make the tube long enough that maybe 1/2 inch sticks out beyond the base of the nose cone. Stuff some wadding or paper towel in the top, put in the Alt15K and a bit more paper towel so that the altimeter doesn't rattle around. Put a piece of tape (masking tape, probably, over the lower end to retain the unit between flights, being careful NOT to seal the tube with the tape. I presume you have some static vent ports in the body of the model.

 

[4regt4]

Put a piece of BT-20 in offset as you suggest. Since there's no accelerometer in the that altimeter, the angle/orientation really doesn't matter. Make the tube long enough that maybe 1/2 inch sticks out beyond the base of the nose cone. Stuff some wadding or paper towel in the top, put in the Alt15K and a bit more paper towel so that the altimeter doesn't rattle around. Put a piece of tape (masking tape, probably, over the lower end to retain the unit between flights, being careful NOT to seal the tube with the tape. I presume you have some static vent ports in the body of the model.

Thanks. Tape was a consideration, but I wasn't sure if it would hold good enough.

Perhaps if I leave some of the BT20 sticking out, I could use a twist tie or small zip tie passing through holes in the BT20.

Hans.

 

[BEC]

That could work, also. Just a twist tie or two, maybe crossed so the the altimeter doesn't sneak by one in the middle on boost.

 

[4regt4]

Base of nose cone. The black is overspray - I didn't mask the base very well.....

 

[cerving]

Gluing a BT20 (or maybe BT50 if you can fit it) into the nose cone is probably your best solution. Just mount the altimeter on a narrow strip of 1/8" basswood, you should have enough room for both the altimeter and a battery. You'll want to plug the forward end to keep it from sliding forward, and use some kind of cap on the open end to hold it in place; a hardwood plug with a couple of #4 self-tapping screws works fine.

 

[4regt4]

It's a perfect fit in the BT20, doesn't move around (laterally) at all. If I were to attach it to a strip of basswood, the BT50 would be necessary.

The 2 rockets that I use a couple of the others in have BT50 payload tubes. I put a piece of foam rubber in the end, wrap the Alt15K in some thin foam, and finish with another plug of foam.

Thanks all,
Hans.