Monday, September 28, 2009

Aerotech Spacers Out!

Aerotech has officially released a spacer system for their 38mm RMS system. It's a bit different from the Cesaroni system, though.

The Cesaroni system simply uses metal spacer tubes that fit inside the motor, taking up the space of one grain. The AT system is a bit more complicated. It uses 3 parts: metal spacer tubes like in the Cesaroni system, a floating forward closure that can go anywhere inside the motor tube, and a choice of forward closures. One allows the case to be used with its normal-sized reloads as well as smaller one and has a large hole in the center; the other only allows use with spacers (ie, use of a 360Ns case with 240 loads but not 360 loads) but provides an eyebolt attachment for your recovery system.

Aerotech recommends using no more than 2 spacers per case, but theoretically 5 can turn a 38/1080 motor into a 38/120 motor. Imagine being able to use G and J loads in the same casing! The only penalty is 1.9" of case length (over the usual case) and about 50g (1.8 oz) per spacer used. In other words, a 360Ns case with one spacer is 1.9" longer and 1.8oz heavier than the 240Ns case alone.

Currently, the system is not yet certified, but this is expected to come by mid-October. The standard new closure, which allows use of the nominal load for the case plus smaller loads, comes with 2 spacers and the floating forward closure for $29.99. The anchored forward closure, alone, is $19.99.

29mm and 54mm systems will likely join the 38mm system soon. I will certainly buy the 29mm system so I can use 60Ns and 120Ns loads with my 180Ns case. (The 100Ns case uses non-standard-size grains and thus wouldn't work with the spacer.) Aerotech is not sure whether they'll make 75mm and 98mm versions only because they would carry significant weight and length penalties versus the nominal size casing.

Like other Aerotech stuff, this isn't necessarily as simple to use as the Cesaroni version, but it's not too hard, and I personally like assembling my own motor from individual parts. Using a Cesaroni load, which is preassembled, seems like no different from using a single-use motor.

The announcement on TRF, Rocketry Planet, and Aerotech's website.

And now, for your enjoyment, my first embedded Youtube video, which shows the assmbly of the new spacer system and 2 test firings.

1 comment:

ScrapDaddy said...

Where can you find these spacers?