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Old 01-09-2009, 02:30 PM
dogcaller dogcaller is offline
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Default 3 questions

OK, so I'm thinking about this stuff more and more now, and luckily I just got two more kits to (help my kids--but they better not touch!) build.

1) I've often disregarded the enclosed launch lugs in favor of cut down drinking straws. Mainly because they're available and larger in diameter, making them more forgiving. Any problem with this idea? I haven't had trouble so far. BTW, I don't compete or do anything serious with these rockets (except serious fun!).

2) Does anyone have a tutorial of the best way (or even better, multiple good ways) to fold parachutes, especially for the smaller diameter stuff? Pics are great! Shroud lines around the folded chute, or no? I do have the directions they come with of course, but often find that collective experience can be a great teacher.

3) How should I judge when to use the longer delays in ejectiong charges
(i.e., C6-5 vs. C6-7)? I figure there must be a theory to it.

Thanks so much!
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Old 01-09-2009, 02:50 PM
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tbzep tbzep is offline
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Quote:
Originally Posted by dogcaller
OK, so I'm thinking about this stuff more and more now, and luckily I just got two more kits to (help my kids--but they better not touch!) build.

1) I've often disregarded the enclosed launch lugs in favor of cut down drinking straws. Mainly because they're available and larger in diameter, making them more forgiving. Any problem with this idea? I haven't had trouble so far. BTW, I don't compete or do anything serious with these rockets (except serious fun!).

2) Does anyone have a tutorial of the best way (or even better, multiple good ways) to fold parachutes, especially for the smaller diameter stuff? Pics are great! Shroud lines around the folded chute, or no? I do have the directions they come with of course, but often find that collective experience can be a great teacher.

3) How should I judge when to use the longer delays in ejectiong charges
(i.e., C6-5 vs. C6-7)? I figure there must be a theory to it.

Thanks so much!


1. If it works better for you, keep doing it.

2. I do the plastic chutes pretty much the way the printed instructions show. In the winter I use some baby powder to keep it from sticking together. In cold weather I always repack the chute just before flight to help give it a better chance of opening. If your chute is made of heavy, stiff plastic, throw it away and get a better chute, either nylon or plastic from somebody like Semroc or Fliskits. In the past, Quest had some terrible chutes, and from the looks of it, some of the new Chinese Estes chutes may be too stiff also. I haven't fooled with any of them yet, though.

3. Use the manufacturer's recommended motors as a guide. If it's windy, the rocket will arc over earlier, so you need the shorter of the recommended delays. Example, D12-3 for windy days, D12-5 for calm days if both are recommended by the manufacturer. If you build heavy, you may need to use the shorter recommended delay regardless. If it's still going up when it ejects, use a longer delay. If it has already descended considerably before it ejects, use a shorter delay. You will soon get the hang of picking the correct delay for conditions and will be able to choose delays without looking at the manufacturer's recommendation and for your own scratch built rockets too. Don't forget that both Estes and Quest make motors and their burn times and ejections are slightly different. If one brand doesn't suit your model, try the other. As an example, Estes A8-3's are often too short and their A8-5's are often too long for some models. Quest makes an A6-4 that works great in this situation. Also, even though Quest and Estes make motors with the same designations, such as the C6-5, their burn times and ejection times are somewhat different.
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Old 01-09-2009, 05:13 PM
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CPMcGraw CPMcGraw is offline
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Quote:
Originally Posted by dogcaller
OK, so I'm thinking about this stuff more and more now, and luckily I just got two more kits to (help my kids--but they better not touch!) build.

1) I've often disregarded the enclosed launch lugs in favor of cut down drinking straws. Mainly because they're available and larger in diameter, making them more forgiving. Any problem with this idea? I haven't had trouble so far. BTW, I don't compete or do anything serious with these rockets (except serious fun!).

2) Does anyone have a tutorial of the best way (or even better, multiple good ways) to fold parachutes, especially for the smaller diameter stuff? Pics are great! Shroud lines around the folded chute, or no? I do have the directions they come with of course, but often find that collective experience can be a great teacher.

3) How should I judge when to use the longer delays in ejectiong charges
(i.e., C6-5 vs. C6-7)? I figure there must be a theory to it.

Thanks so much!


From a personal perspective...

1. I use the launch lugs that come with the kits. If you should ever have a binding issue with your model on the rod, chances are it's not the launch lug. It will nearly always be the rod. Always check the rod for kinks or other bends which should not be there. Also, check for end-cut burring, where the chop might not have been clean. Over time, the rod will acquire a layer of corrosion, whether it's made of aluminum or steel, and this will act like glue to the lug. Keep the launch rod wiped down with a paper towel before and after each session. If you see any rust (on the steel rod) polish it off with sandpaper or emery cloth, then wipe it down. The smaller-diameter lugs keep the rocket from skewing as much as a soda straw, which can grab the model and affect the flight.

2. Look at some of the Centuri plans on how they recommended a parachute be folded. They had some good illustrations on the process. I do wrap the lines around the chute, and not always loosely. Always use talcum powder at the start of your session, as this keeps the plastic from sticking. Keep your parachutes separate from the rockets when you are not flying. Attach the shrouds to snap links; attach the chute to the rocket just before flight, and remove it immediately after the flight.

3. As Tim already said, follow the manufacturer's suggested motor/delay combinations. If you're "rolling your own" designs, you really need the use of a tool like RockSim to determine which motor and delay will work best. Really, if you're using typical Estes black powder motors, then the most common motors will be the A8-3, B4-4, B6-4, and C6-5. While not necessarily the best motors for every flight, these pairings will put you in the middle of the zones most of the time.
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  #4  
Old 01-09-2009, 05:40 PM
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Bazookadale Bazookadale is offline
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I prefer to go one size bigger on launch lugs - substitute 3/16 for 1/8, 1/4 for 3/16, ect.
I do this for 2 reasons, first 3/16" lugs will never bind on a 1/8" rod , second as a lazy pearson I don't have to switch rods that often if I have 2 choices . Sometimes this causes confusion at a launch, I have several G powered rockets that were designed for 1/4" rods, I have 1/2" lugs on them and sometimes an RSO will insist that I put it on a high power pad even though I have flown it a hundred times of a 1/4" rod!
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