Friday, July 9, 2010

Big 29/40-120 reloads

From the Aerotech Facebook page (the only thing I still legitimately like about that site anymore):

Today, they tested a new 29/40-120 reload. It generated 150 Ns of total impulse. That's a whole lot more than the current G loads for the case, which top out at 120 Newton-seconds (G64). (G76G is 115, G71R is 107, G53FJ is 91).

That means it must have been a high-impulse Blue Thunder blend (the only more efficient propellant, Warp Nine, isn;t used in such small cases), with an Isp (efficiency) of 245 (assuming 62.5g of propellant, the max that usually fits in the case). That's very high; most blends top out at about 200. See previous post.

The burn time is apparently 1.17 seconds, for what is about a G128T. That's an awesome motor, and would kick some major ass if it's released as a commercial load.

But it gets better. Oh yes.

They're looking to put an H load in it. Obviously a baby H - just over the limit at 161 Ns or so. Average thrust between 100 and 120. That's pushing 263 for the Isp for 62.5g of propellant. Even if they've got 72.2 grams - the amount in the old G33J, and the maximum that'll fit in the casing - that's still a nice high 228.

I thoroughly approve of this, and I really hope they get a motor to market. I have several rockets - the Mozzie chief among them - that could rock on a big G or baby H, but can't quite fit a 29/180 casing.

Also, since it's a small amount of propellant, it'll be cheap. And everybody, it seems, has the hobby casing (29/40-120) for mid-power stuff; it'd be cheaper to certify with that than by buying the larger casing.


Dick said...

I wouldn't discount a Warp9 derivative. They originally said Redline wouldn't work in that case. And then they said Mojave Green wouldn't. Then they released them and made my 29/120 cases essentially useless.

Time will tell. I just hope it has a delay train.

KenKzak said...

No reason at all the red and green wouldn't work in the 29/40-120 case. However, I suspect that for a while Aerotech was considering the retail reloadable programs to be a dieing cause. I'm glad their philosophy has now gone the other way.