Ye Olde Rocket Forum - View Single Post - Scrounged-Up Designs 2006

Quote:

Originally Posted by CPMcGraw

Steve,

What's a good weight value for an electronics package, all-up? I've been wanting some kind of "mass value" to save in the RockSim database for HPR future projects, but I'm not certain the current measurements in the database are "complete", as in, does the weight shown include batteries and pyro holders and "other stuff"?

What's a good "ballpark" figure?

I use the PerfectFlite miniAlt/WD. A PerfectFlite miniAlt/WD Altimeter & 9v battery I plug in 2.293 oz in my RockSim designs. I also use one or two (for single or dual deploy) of the QuickBurst EZ small ejection canisters and I just weighed one of those at .2 oz on my scale. I'd add a couple of grams of black powder to that and you should have a real close estimate to ballpark it.

That's what I use. I'll look through my RockSim designs. I have actual weights for the Loc 3" and 4" electronics bays in a couple of the Loc rockets I built. I'll get that for you.

Edit:

Ok, I also weighed one of the QuickBurst EZ large ejection canisters. Those are .6 oz each. The only project I ever used the large ejection canisters with was 5.5" in dia. The small canisters as a rule will generally work well with up to 4" dia. airframes.

Just FYI and to give you some idea of how Loc sets up their electroics bays, I attached a file for a 3" diameter rocket I built that was designed with one from Loc. To sim the altimeter in the design, I center it in the middle of the electronics bay as a mass object. It's pretty much centered on the little plywood board they give you anyhow. The mass item in the design marked as "EB-3.00 Hardware & Additional Components" is all the 1/4-20 hardware, nuts, plywood board ect. - really everything else other than the bulkheads and couplers. I just center that mass object too since those parts would pretty much balance at the cg of the bay.

I guess to sum it up if you are flying your electronics package in a payload section instead of an electronics bay you'll probably want to add mass objects for at least the altimeter and battery, one or two of those disposable ejection canisters, 1 - 2.5 grams of black powder in each canister and a small plywood sled or weigh some foam rubber if you decide to let the altimter ride without mounting it