AVI Motors - Yellow paint on ends - Is it OK?

Yellow paint was to make them "Gold". They were marketed as "Gold Motors".

Gold paint on booster will do NOTHING negative to your ability to stage.

I used Many of these motors from every year of their production and I know about the problems they had and how they solved them.

Things to keep in mind with AVI Gold Motors:

• The long D (18mm) and E (24mm) motors were made in 2+ versions. First version was very long and had oodles of total impulse. Problem was they burned so long they eroded a hole in the side of the casing (Challenger without the joint - straight through the side of the casing). This resulted in "Major Malfunctions". Solution was to redesign the motors shorter with less propellant/shorter burn/less total impulse.

• Motors had delay elements epoxied in place. Think of an Estes D12-0 (or a longer version in the case of the AVI E) with a small length of 18mm motor tube containing only the delay and ejection epoxied on top. Well, when the booster burns through the top it exposes a HUGE surface area that burns all at once and produces a HUGE second thrust spike (almost off the test stand scale). This overpressure could blow out the already eroded casing aneurism. On the really fat motors (the E24/F23 IIRC) the sound was LOUD. I flew one in Superroc at NARAM 19 and won, but the RSO thought the motor exploded when it had actually just reached burnout. Solution was to paint some of the upper surface of the propellant before epoxying in the delay element. I don't remember if he used epoxy or yellow paint on this inside coating.

If you need igniters for these motors, see my eBay listings for nichrome wire below. (I got in a free plug)

-Fred Shecter NAR 20117

These were their "gold" series motors, thus the "gold" caps.

never realized they did it to the booster motors too.