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-   -   DECAP's (http://www.oldrocketforum.com/showthread.php?t=9616)

Carl@Semroc 07-19-2011 11:28 PM

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"?

BEC 07-20-2011 01:01 AM

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?

Mark II 07-20-2011 02:14 AM

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.

chanstevens 07-20-2011 05:55 AM

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.

Eagle3 07-20-2011 08:47 AM

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

Vanel 07-20-2011 09:13 AM

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.

Bazookadale 07-20-2011 10:07 AM

1) Yes
2) If they can't figure it out they shouldn't be flying rockets

Chas Russell 07-20-2011 02:32 PM

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.

ghrocketman 07-21-2011 10:15 AM

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.

chanstevens 07-21-2011 11:20 AM

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?


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