 |
 | Home | Contact Us | FAQ | Search & Site Map | Link to Us |
 | Sign In | Join | Other 45 Sites in Network |
| HomeDiscussion Groups General ModelsRailroadsRocketsRadio Controlled Air ModelsHelicoptersLand ModelsWater ModelsModelGeeks.com Contact UsLink To UsSearch & Site Map |
Model Forum / General / Rockets / May 2008Sizing secondary deployment charges
I could use a bit of advice on sizing secondary deployment charges. Rocket is 6" diameter, dual deploy, three #2-56 shear pins attach the nose cone, 20 pounds total weight. In ground testing I got a nice clean ejection with 1.75g for apogee and 2g for the main (ffffg powder). I've heard folks say they use 50% additional powder for the secondary charges, but that sounds excessive. I was thinking more in terms of 10% - but is that adequate? Kevin On May 21, 4:57 pm, ke...@askforaddress.com wrote: Is there a such a thing as different sized condoms to fit the different sized penis's as I know you rocketeers sure would not like to shove up a wrinked old condom up some poor old butthole. You all did not get the moniker of chute packers for nothing! Guyess we need to wait for the in house guru Freddie Boi or Darrell or his other brother Darrell or his other brother Darrell to get done their w.nking and post the answer. > On May 21, 4:57 pm, ke...@askforaddress.com wrote: > Is there a such a thing as different sized condoms to fit the [quoted text clipped - 4 lines] > brother Darrell or his other brother Darrell to get done their w.nking > and post the answer. We wondered where Art Deco had gotten to! >Is there a such a thing as different sized <Moron posting snipped> > > We wondered where Art Deco had gotten to! And you just had to answer the moron. Killfile and his posts go away; unless someone like you responds. > >Is there a such a thing as different sized <Moron posting snipped> > > > We wondered where Art Deco had gotten to! > > And you just had to answer the moron. Killfile and his posts go away; > unless someone like you responds. Get off the line you fool! >>>Is there a such a thing as different sized <Moron posting snipped> >> [quoted text clipped - 4 lines] > > Get off the line you fool! Oh, so your one of those morons also.... Plonk you go.. > >>>Is there a such a thing as different sized <Moron posting snipped> > [quoted text clipped - 10 lines] > > - Show quoted text - Surely your jot caloing Freddie Wallace a f.cking fool now are you ? hahahahahhhhhha a fool and a dead corpse f.cker is what Freddie Boi is! > On May 21, 4:57 pm, ke...@askforaddress.com wrote: > Is there a such a thing as different sized condoms to fit the [quoted text clipped - 4 lines] > brother Darrell or his other brother Darrell to get done their w.nking > and post the answer. > I could use a bit of advice on sizing secondary deployment charges. > [quoted text clipped - 7 lines] > > Kevin If I understand your question, I equate "secondary deployment charge" to the same acronym, "back-up charge". If that is the case, I don't use 50% or other fractions in the secondary/back-up charge. As an example; if I use 2gr in the primary charge, I use 2gr or a slightly larger, (say 2.5gr), in the secondary/back-up charge. My reasoning is simple: If the primary charge fails to deploy the recovery stage completely, lets not take any chances by using a less robust back-up/secondary deployment charge-- reason; "a partial separation from the primary may have caused jamming of the nose cone or coupler in the body tube, requiring as much or greater force to effect back-up/secondary separation/recovery deployment. Hope that helps... Fred I only use one charge, even with redundant HW... Then an ematch from each boards into the same charge. Lets say that 2g of BP will do the job. I might add a bit more (.5g). A bit more pressure, but got a lot. Using separate charges, each at 2g (or 2g and 3g as in your question), there is a worst case scenario - that is both charges go off at the same time (if you're using the same two boards, this is more likely), and then the pressure is double (or more) what you need. A very "energetic" separation could result. Even if only one charge goes off, it could set off the second one... (tiny bits of burning BP hit the second charge). BTW, I also never never use two of the same boards for redundant (not even the same manufacturer). Don't know if it's still out there, but missleworks had a really good description for calculating the required BP in there docs, and it was available on their website. > I could use a bit of advice on sizing secondary deployment charges. > [quoted text clipped - 7 lines] > > Kevin For the most part I use one charge for apogee also. However, I sometimes use two charges on the mains and change the altitude setting on one of the hardware devices. I use Adept, Missleworks, and Perfectflite devices, most of the time, and seldom mix brands. Like you, I use only one charge for apogee, but like I said, (mostly on the first flight), I use two charges for main deployment. I use sealed charge containers, so never worry about chain firing the back-up charge. Atlantic Rockets also had a reliable calculator. When I get time today, I'll try and find it on my laptop and post it to ABMR. Fred > I only use one charge, even with redundant HW... Then an ematch from > each boards into the same charge. [quoted text clipped - 29 lines] >> >> Kevin I worry that something might cause the containment to fail. Maybe I botch the tape job and it comes open. Or the laundry moves around and pulls the e-match harness. I figure an e-match and powder are cheap so I do completely independent chains on a large project. The exception to that is when I use something like the RouseTech CD3. I put two e-matches into the single mechanism. Your mileage may vary... 8) Best wishes, Will > I only use one charge, even with redundant HW... Then an ematch from > each boards into the same charge. ...  SignatureWill Marchant, NAR 13356, Tripoli 10125 L3, FBIS kc6rol@amsat.org http://www.spaceflightsoftware.com/will/ |
Reply to this Message |
 Sign In
 Join
 My Latest Posts My Monitored Threads My Blog My Photo Gallery My Profile My Homepage Start New Thread Enable EMail Alerts Rate this Thread
|
©2008 Advenet LLC Privacy Policy - Terms of Use
This website includes both content owned or controlled by Advenet as well as content owned or controlled by third parties.