Ye Olde Rocket Forum

Go Back   Ye Olde Rocket Forum > Semroc > SAM - Semroc Astronautic Modeler Team
User Name
Password
Auctions Register FAQ Members List Calendar Today's Posts Search Mark Forums Read


Reply
 
Thread Tools Search this Thread Display Modes
  #1  
Old 07-19-2011, 11:28 PM
Carl@Semroc's Avatar
Carl@Semroc Carl@Semroc is offline
Junior ??? Rocketeer
 
Join Date: Mar 2005
Location: Knightdale, NC
Posts: 1,470
Default DECAP's

DECAP's (delay ejection charge auxillary packages) are not on the survey, but I have done some work characterizing them. The projected prices show a difference in booster engines and delay engines. This reflects the fact that a booster takes 2 seconds less to make than a delayed engine and the cost of black powder is about the same as the cost of the delay in an 18mm A engine, so there is a real cost difference.

Briefly, a DECAP is about .51" diameter by 1.2" long and glues inside a booster engine to add the delay and ejection charge. They would be available in all times from 2 seconds to 9 seconds. They would also be available as .5 g ejection charge (standard 18mm load) and 1.2g ejection charge (standard 24mm load). So if you wanted a B5-5, you would glue a DECAP-5 inside a B5-0 engine. If you wanted a C5-4 in a long, large diameter tube, you would glue a DECAP-4X inside a C5-0.

Retail price for a singe DECAP is going to be in the $1.00 range, but the difference in an 18mm booster and delay engine is about $.75. So a B5-4 would cost about $3.25 if prepackaged, but $3.50 if it was made with a booster and DECAP. Questions are:

1. Would it be worth the extra $.25 to have the ability to select delays?
2. Would the average (over 18) user be able to "figure it out"?
__________________
Carl McLawhorn
NAR#4717 L2
semroc.com
Reply With Quote
  #2  
Old 07-20-2011, 01:01 AM
BEC's Avatar
BEC BEC is offline
Master Modeler
 
Join Date: Feb 2009
Location: Auburn, Washington
Posts: 3,026
Default

Carl,

That is very interesting....

I know I have found myself in situations where I wished I had a delay between existing available delays amongst Estes/Quest motors - your example of a 5 second delay on a B impulse motor is certainly one of those.

So - I vote "yes" on question number one.

On number two....not so clear. If all goes the way you wish it to, how widely would your motors be available? The reason I ask is that I expect a bit of a difference in the willingness to be careful and pay attention (and the ability to follow directions) between those who would seek an alternative to mass-marketed motors either directly from you or from specialist dealers compared with those who might just encounter rocketry products in a mass-market type store.

You're suggesting the need for something not unlike the understanding necessary to assemble reloadable motors successfully. I wonder how much handholding Aerotech or Apogee or Cesaroni or such have to do?
__________________
Bernard Cawley
NAR 89040 L1 - Life Member
SAM 0061
AMA 42160
KG7AIE
Reply With Quote
  #3  
Old 07-20-2011, 02:14 AM
Mark II's Avatar
Mark II Mark II is offline
Forest Sprite
 
Join Date: Dec 2006
Location: Back Up in the Woods
Posts: 3,657
Default

My thoughts:

1. Yes, of course.

2. Installing a DECAP sounds like a much simpler process than, say, assembling a reloadable motor. AeroTech and CTI seem to manage just fine by including detailed instruction sheets with their motors. I don't know how many reloadable motors and reloads are sold to naive customers who have no idea what they require and I suspect that most people who buy them have some notion of what they are all about. This does not mean that every customer uses them properly, but the rocketry community is swift to condemn anyone who squawks about a motor failure when it is evident that the person didn't follow the directions for its use. Black powder motors have a lower "education" threshold for potential consumers, but even novices have to read some instructions before they even know how to ignite them properly. I think that the imagined scenario of a totally naive customer buying black powder motors without having a clue about how to use them isn't actually that likely; most people would not be inclined to buy something that they have no idea how to use. So the vast majority of your potential customers would either know already what they were getting or would at least realize that they needed to read some instructions on what to do with the darned things. So, yes, I think that the average user would be able to follow the instructions in order to use the product properly, especially if the packaging and the motor label clearly indicates that a delay and ejection charge module must be added to the motor to make it capable of deploying a parachute or streamer.
__________________
Mark S. Kulka NAR #86134 L1,_ASTRE #471_Adirondack Mountains, NY
Opinions Unfettered by Logic Advice Unsullied by Erudition Rocketry Without Pity
+09281962-TAK-08272007+
SAM # 0011
Reply With Quote
  #4  
Old 07-20-2011, 05:55 AM
chanstevens's Avatar
chanstevens chanstevens is offline
Rocket buildin' machine
 
Join Date: Jan 2007
Location: Cincinnati OH
Posts: 520
Default

I'd doubt the wider market appeal of them, from from a competition perspective I can say this would be VERY attractive. Once certified, you'd probably get a few of us that would just load up on a hundred or so because whenever we find something this good, we buy a lifetime supply before it disappears.

I do think the delay flexibility would be worth it as an option, not as a forced standard. I think most over 18 would be able to figure it out. I just think most flyers really aren't going to pay much attention to the difference between a 4 and a 5 second delay. If their chute comes out and their rocket comes back, they're happy. Slightly before/after apogee is for the purists.
Reply With Quote
  #5  
Old 07-20-2011, 08:47 AM
Eagle3's Avatar
Eagle3 Eagle3 is offline
Administrator
 
Join Date: Jun 2004
Location: Manchester,MI
Posts: 1,262
Default

Yes and Yes, but as Bernard mentioned, you'd have to be prepared for a lot of virtual hand-holding for number 2. Enlisting SAM members to help out on that could be a major plus.

It sounds a lot easier to do than a typical AT reload, somewhat easier than a Loki, but not as easy as a CTI. To me though, if you can glue fins on the right end of the body tube you should be able to do this.

Buzz
__________________
Quando Omni Flunkus Moritati
Reply With Quote
  #6  
Old 07-20-2011, 09:13 AM
Vanel Vanel is offline
Master Modeler
 
Join Date: Jun 2005
Posts: 798
Default

Quote:
Originally Posted by Carl@Semroc
1. Would it be worth the extra $.25 to have the ability to select delays?
2. Would the average (over 18) user be able to "figure it out"?


1) Definitely!
2) I would certainly hope so - if they can put a rocket together, they should be able to handle a DECAP.
__________________
Up next:
Under construction:
Under repair:
In finishing: ERP #46 Skylance
In primer: Estes Olympus, Boyce Redstone missile
In paint: Jupiter-C PMC
Ready for decals:

Bill Cooke
NAR #31312
TRA #19705
SAM #0001
Huntsville, AL

My rocket blog
My rocket fleet
Reply With Quote
  #7  
Old 07-20-2011, 10:07 AM
Bazookadale's Avatar
Bazookadale Bazookadale is offline
I wish I was a spaceman!
 
Join Date: Jan 2006
Location: Elizabethtown,PA
Posts: 431
Default

1) Yes
2) If they can't figure it out they shouldn't be flying rockets
__________________
Did the chicken really cross the road, or did the
road move beneath the chicken? Albert Einstein

You Can't break the laws of physics but they can break you. Christine McKinley


Dale Greene

Mentor, Penn Manor Rocket Club

VISIT SPAAR
2010 Calder Cup
The Old West
2009 Calder Cup

" Speaking the Truth in times of universal deceit is a revolutionary act. " George Orwell
Reply With Quote
  #8  
Old 07-20-2011, 02:32 PM
Chas Russell's Avatar
Chas Russell Chas Russell is offline
Retired Missile Technician
 
Join Date: Mar 2005
Location: Fort Worth, TX
Posts: 969
Default

Having worked Standards and Testing way back when, I think you would have to get their input about what they would certify both from a safety and a contest certification point of view. I have WAY too many 18mm composite reloads as once a pak is impounded and then opened, it cannot be used for competition again (must be an unopened pak). This is so the modeler does not "modify" components. This could be carried oper to a multipak of delays.

Seeing as some of the S&T members will be at NARAM for the Board of Trustee meeting, you might want to take them into your confidence and see if they have issues or suggestions.
We didn't call it Standards and Torture fur nuthin'!

Chas
BoT 9 years, S&T 3 years, first MESS chair, NARTREK 3 years or so, Contest Board very briefly before overseas assignment...
and the beatings go on.
__________________
Charles Russell, MSgt,USAF (ret.)
NAR 9790, Lvl 1
SAM "Balls Three"

Last edited by Chas Russell : 07-20-2011 at 02:33 PM. Reason: Typo
Reply With Quote
  #9  
Old 07-21-2011, 10:15 AM
ghrocketman's Avatar
ghrocketman ghrocketman is offline
President, MAYHEM AGITATORS, Inc.
 
Join Date: Jul 2005
Location: Michigan
Posts: 11,267
Default

The DECAP idea sounds great !
Every delay for every engine.

As a side note, one could do all sorts of "unique" things with say a B5-9 in a large rocket....buuuwwhhhaaaahaha !

NAR needs to relax their draconian competition rules regarding reloads, PERIOD.
There is no reason AT ALL why they could not re-seal the 3 pak with a special NAR only tamper-proof seal.
__________________
When in doubt, WHACK the GAS and DITCH the brake !!!

Yes, there is such a thing as NORMAL
, if you have to ask what is "NORMAL" , you probably aren't
!
Reply With Quote
  #10  
Old 07-21-2011, 11:20 AM
chanstevens's Avatar
chanstevens chanstevens is offline
Rocket buildin' machine
 
Join Date: Jan 2007
Location: Cincinnati OH
Posts: 520
Default

Quote:
Originally Posted by ghrocketman
The DECAP idea sounds great !
Every delay for every engine.

As a side note, one could do all sorts of "unique" things with say a B5-9 in a large rocket....buuuwwhhhaaaahaha !

NAR needs to relax their draconian competition rules regarding reloads, PERIOD.
There is no reason AT ALL why they could not re-seal the 3 pak with a special NAR only tamper-proof seal.


Draconian rules? Sheesh, get over yourself. The reload rule is pretty stupid, but so is complaining about it when all it takes is writing up a rules change proposal and shooting it off to the appropriate volunteer (Jim Filler at the moment). Once a year everyone gets to vote on the proposals, and whatever passes goes into effect. The NAR itself doesn't write any rules or make any decrees. It's about the most grass roots, democratic, power-to-the-people part of the NAR and I'd think that's a bandwagon right up your alley for jumping on.

Out of curiosity, how many contests have you flown where you were either incovenienced by this Draconian rule, or did not fly specifically because of this Draconian rule?
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT -5. The time now is 06:53 PM.


Powered by: vBulletin Version 3.0.7
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Ye Olde Rocket Shoppe 1998-2021