So, the question is, with an aerotech motor, how does one increase the ejection charge delay?

You get the L delay, from Tim Thomas. Every sim I've ever done with the I357 puts the delay way longer than the M. Technically, it's RDK-13+ for 15 seconds. PM me your e-mail, and I'll e-mail you two handy .pdf charts, showing all possiblilities. Some are educated guesses at what can be done, most are straight from AT.

Thanks, Bruce, so I can assume that the L delay is longer than the M? Smehow I would think the opposite! Whats RDK-13+? FYI, the flight was ~10 sec. to ejection. Does that sound right for the M?

S=short
M=medium
L=long

This is from the AT '05 catalog:

Short=Approx. 6 sec.;
Medium=Approx. 10 sec.;
Long=Approx. 14 sec.;
X-Long=Approx. 18 sec.

Whats RDK-13+? FYI, the flight was ~10 sec. to ejection. Does that sound right for the M?

So, yes, 10 sec is dead on M. And, probably the Reload Delay Kit 13+ is a little long @15, first time I typed in RDK-12+, which should give you 14. The info is on the RDK bag (and Tim has these), as to what reloads those particular delays work for and the expected delay in time. The MAIN thing to remember is that each delay is specific for a certain propellant's burn time. You can't assume that, say, a 12+ is going to give you such and such a delay with any propellant, i.e., redline, blue thunder, or white lightning. They won't. Next launch, if we're both there, and if Tim's too busy, I can show which one will work. Plus I'll bring my charts. If I get a chance, I'll try to go through my delays and get the correct kit # for you.

Okay, found it.. it IS a RDK-12 PLUS that will make an I 357 go 14 seconds before firing the motor ejection charge.

They do vary in length of time as a S,M,L as per the reload. Not all M are the same if I remember correctly. or at one time it was that way.. May be just me showing some age..lol.. They are pretty well all the same now per the class designation. Best to get it long and have to drill it to shorten it I believe.

8) I too have a Phobos, and I fly it mostly on H motors. I use 10 to 11 seconds for the H. It is almost always dead on. I have flown it on I205's and use the whole 15 sec dalay. The I 357 is a pipey little motor. Go with all the delay you can find. I have all of the RDK kits. I use Bruce's charts all the time. Before you fly, check the chart for the motor you are going to fly and get the longest delay. They are only 2.00 ea. or 3for 5.00. I always bring Bruce's charts to the launch, if you need to see it , just ask. The Phobos is such a nice flyier, but it will get out of sight in a flash! 8)

thanks for all the info guys! if there is one thing i can count on ncr for, it's broad and deep knowledge of all things rockets, and a willingness to share that knowledge freely!

tim you are correct, based on my first three launches, the phobos is perfect on a 10-second delay with an h motor but with the i357 MUCH more is needed. if i can believe the perfectflight altimeter (and i think i can) the rocket was going around 150mph when the ejection charge blew. that would explain the weird way the webbing got tangled up! probably a good thing for that day; almost lost the rocket as it was; but i'd like to see just how much it can do when given the chance. next time out i'll try the i357 again and see you for the rdk. bruce, your charts sound awesome ... where do i get a copy?!

bruce, your charts sound awesome ... where do i get a copy?!

I got them online a while ago at:

http://www.rocstock.org/wizards/rms-delays_2938.pdf

This link gives you the warnings:

http://rocstock.org/wizards/caveats.html

For some reason, I can't access their 54mm version of rms delays.

Here is another one, though not as comprehensive: http://www.info-central.org/propulsion_atdelays.shtml

I have had good luck with this web site.

http://webalt.markworld.com/webalt.html

It has been right on with the delay. I fill out
everything except I leave the delay length and
chute size blank. I look at the time to max alt.
or turn over.

I have not flown as many as some. So I do not
have a large data base.

The sites altitude calculations were some what off.
It said on my Big Nuke with a K445, the altitude would be
3650 and my altimeter beeeeeped out 4748. I am not sure
yet what I filled out wrong or what. I have faith in the
altimeter beep. Its an RRC2x and two people counted
out 4748.