Lots of space in an H130

Spent some time assembling motors for this Saturday’s launch and ran into this with a H130:


There is a TON of space at the aft end. The kit does not include any spacers to fit between these “little” grains and of course the genetic instructions do not mention anything specific to the H130. I am used to some “grain rattle” with Aerotech reloads, but this doesn’t seem right

Does this look correct to you all or am I missing some parts?

Thanks

Looks OK to me, I've put together quite a few H130s and all had plenty of "grain rattle". Definitely no grain spacers needed. Similar motor shows room, but maybe a bit less:

https://www.aerotech-rocketry.com/c...gs/38mm_hp_rms/38-240/38-240_h123w-l_assy.pdf

Seems normal to me.

Interesting. I have an H130 I was going to use this Sunday. Mine is going to go in the 360 case with the RAS spacers. I'll work on it tomorrow and post a pic. See if it has an unusual amount of space.

thanks all, good deal

tOD, I look forward to hearing what yours looks like.

Theory said:

Spent some time assembling motors for this Saturday’s launch and ran into this with a H130:
View attachment 388174

There is a TON of space at the aft end. The kit does not include any spacers to fit between these “little” grains and of course the genetic instructions do not mention anything specific to the H130. I am used to some “grain rattle” with Aerotech reloads, but this doesn’t seem right

Does this look correct to you all or am I missing some parts?

Thanks

Click to expand...

Looks right. You need a little room for the nozzle to insert, then the o-ring and aft closure.

Steve Shannon said:

Looks right. You need a little room for the nozzle to insert, then the o-ring and aft closure.

Click to expand...

that's just it though, per the instructions there is a fiber insulator placed at the end of the liner then the o-ring / nozzle assembly. if it was like the 29 40-120 system then I would be 100% ok with this, as there is an insulator, the gap is "held"

OK Theory, here's a couple of pictures from my assembly. I used a 38/360 case, floating forward closure, and one spacer from the RAS. One photo is of the liner with the grains on it sitting flat on the table. The liner is actually longer than the stack of grains. Since the delay spacers are the same OD as the liner the gap is going to persist in the finished assembly. Second photo is the aft end after the delay assembly, forward seal disc, forward spacer and floating forward closure are installed and the finished assembly is stood on end. Last step was to install the aft seal disc, gasket, nozzle, and rear closure. There was some grain rattle after all was tightened up. There would have to be due to the difference in the length of the liner compared to the length of the grains. I've built this motor before, but can't remember for sure if it rattled. I'm also not sure if there is more our less rattle depending on propellant type. Somehow I think the reds and the black jacks don't have as much space when completed. Let me know how yours turns out. I'm hoping to fly mine in a Wildman Darkstar Jr on Sunday. Should get about 1100' our so.

thank you!

I will measure mine when I get home but from here it looks to be almost exactly the same.

if all goes well the H130 will be the second flight in my new LOC Caliber ISP this coming Saturday.

Not the best measurement. Ok, it’s really bad, but it’s darn close to yours.



Gonna tighten the closures and fire it!

Theory said:

Not the best measurement. Ok, it’s really bad, but it’s darn close to yours.

View attachment 388212

Gonna tighten the closures and fire it!

Click to expand...

That's the spirit!
I confess I'm wimping out with an H130 in this rocket. I flew it on an I364 and thought it was gone forever.
Low and slow until I finish the mounting for the Eggfinder GPS.

I'm kinda doing the same as I built my Caliber for much larger motors. just looking to get in a few shake down flights on Saturday (H220 & H180). Hopefully I will be able to pick up an I300 or an I435 at the launch for the fall. that flight will be much more "my style"

Hi Theory! Here's a shot of my Darkstar Jr lifting off on the H130W. 1183ft. First test of my Eggfinder GPS. Landed within sight so not much of a test.

Nice!

Sadly I spent a good deal of time getting my Caliber’s first flight (H220) out of a bunch of trees so I didn’t get to the 180. No worries though, it’s still loaded and will fly in September

Theory said:

Nice!

Sadly I spent a good deal of time getting my Caliber’s first flight (H220) out of a bunch of trees so I didn’t get to the 180. No worries though, it’s still loaded and will fly in September

Click to expand...

I just wanted to add my $0.02, when storing AT motors I usually loosen the aft closure to decompress the O-rings and improve fire safety, i.e if for any reason the motor ignites it doesn't shoot off in a random direction and instead blows appart and just burns in place.

Just my $0.02.

Theory said:

Nice!

Sadly I spent a good deal of time getting my Caliber’s first flight (H220) out of a bunch of trees so I didn’t get to the 180. No worries though, it’s still loaded and will fly in September

Click to expand...

Glad to hear you got it back. I haven't ended up in a tree yet (still too new), but I know it's coming. A guy at the launch today was passing out cards for a local tree guy. I thought I was headed for the barn roof, but the wind was with me.