Air Flap Release For HDTT
(Horizontal Deployment For Tomy Timer)
Last Edited May 25, 2001
Releasing Tomy Timers has always been a challenge for several reasons. The original method for releasing Tomy Timers that I am away of was began by Bruce Berggren and involved jamming the gears with a rod that was yanked from the rocket on take off by a string tied to the launcher or ground. This is the method I used on Insane Air. The problem was that the jolt of pin removal and timer release created a vibration in the rocket that I feel was eating up a lot of energy during flight.

This challenge was the first to make me interested in coming up with an alternate method of release. The other challenge is that I work with Science Olympiad kids that can use timers for deployment, but could not use a release that separated from the rocket.

Based on need the Air Flap Release (AFR) was invented for Tomy Timers. I have used AFR on both high performance FTC's and Standard Soda Bottles. It was also used on Connally High Schools Science Olympiad rocket winning Division C of the 2001 National Championship and their rockets had the longest flights of the tournament.

With this system, timing can be set to release the chute consistently within .1 seconds of the desired time.

How does it work?  The Air Flap has a hole in it and when the flap is raised to a horizontal position, the pin from the Tomy timer sits in the hole in the air flap. Upon take off, the flap is pushed down and the timer is released.
This is a picture of the AFR in locked position on my 1 Liter high performance rocket "Shot Gun".

The entire weight of AFR is under 1 gram.

The flap is made from 1/32 inch thick Bass Wood. On later versions of this system and on the SO rockets, we place the wood under the hinge, so that the pin on the Tomy Timer Knob was released by the hole in the nylon hinge, not the hole in the
The AFR is shown in the released / flight position. Note the 4 pins on the Tomy Timmer knob. This allows the system to be set for very accurate release timming.

The hinge for the AFR is a nylon hinge obtained from a hobby shop. The hinge is glued with PL Premium onto the bottle or FTC and the hole for the Tomy Timer is drilled right through both the hinge and the bottle. This additionally secures the hinge in position. The wire that holds the Tomy Timer in posittion also wraps around the hinge.
This is the AFR as seen on "Insane Air Light" my newest version of my 772' altitude FTC Insane Air.

Note that the knob on the Tomy Timer has the simple 2 pin system which is adequate for most WR needs.
In the released / flight position the AFR lays flat along the "Insane Air Light's" rocket body behind the Tomy Timer knob.