Monday, October 13, 2014

Estes Altimeter Holes Part 1

Before punching holes in a body tube for the altimeter, I checked the instructions for three altimeters - The Estes Altimeter and the older and newer Jolly Logic One

Installation Tips:
Altimeter One (OLD)
“We advise that you punch at least three 1/16" to 1/8" diameter holes evenly spaced around the payload bay or the fuselage as close to the nosecone as possible, but low enough not to be blocked by the nosecone once it is inserted.”

Altimeter One (NEW)
“Add a few holes to allow air to escape at altitude.
The larger the airspace in your model, the larger the holes should be."

Estes Altimeter
". . . it is necessary to create 3 to 4 evenly spaced 1/8 inch square or round holes, approximately 2 inches below the open end of the body tube or payload section of your rocket. Cut holes using a hobby knife or 1/8 inch drill."

I knew I couldn't get three or four consistent square holes using an X-Acto knife. How many times has the knife cut farther than you would have liked when cutting a simple engine hook slit?
Cutting 1/8" squares would mean 12 or 16 small straight cuts! That's a ruined tube just waiting to happen.
I could spin the knife tip drilling a round hole. That works pretty well for smaller holes but when the diameter gets larger it's hard to keep the hole round. Drilling with a knife tip could chip the paint.
I'll just punch them.


  1. I use a micro hand drill - the apogee way; they have a video on the subject. I put those in in my reflector model and well most rockets with a payload bay. After all what is probably the number one item that you'll put in a low level rockets payload bay?

    1. Hi Scott,
      I've got micro drills but the punch is quicker and leaves cleaner edges. The Jolly Logic instructions said the the hole sizes should be larger on a larger model. This BT-60 Patriot got holes about 1/8" diameter.