CTI Prol 6gxl - Northern Colorado Rocketry

This topic has 23 replies, 8 voices, and was last updated 14 years, 5 months ago by SCOTT EVANS.

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April 8, 2011 at 8:47 pm #41236
greywolves
Hi everyone,

I’ve been planning my Kestrel rocket, and i understand the 6grain XL motors are all plugged, and have 1/4-20 threads in the forward end.
I’ve looked at the CTI site and it shows some pictures, but not well enough for me to figure this out.
#1- How far past the casing does the motor hang out, forward end?

#2- How many threads or how much 1/4″ all thread will the forward end hold?

Reason I ask, I’m planing on having a bulkhead in front of the motor, that i can then thread the motor on to, along with some friction fitting tape, although not sure how much tape i could do and still turn the motor inside the tube. Any and all thought welcome, thanks guys.
April 8, 2011 at 8:56 pm #54120
SCOTT EVANS
I have a couple i could show you. Or I could take a picture. 1.5 to 2 inches i guess.
April 8, 2011 at 9:16 pm #54121
greywolves
Hey Scott,

Motor hangs out 1.5 to 2″ out of the casing? ok cool.
Do you also know about how deep the 1/4-20 hole is?
Thank you sir!
April 9, 2011 at 4:28 am #54122
SCOTT EVANS
I was way wrong picture is split wierd but you can see the measurement.
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April 9, 2011 at 5:59 am #54123
greywolves
Thanks Scotte, looks like 5/8″ to me. 😀
April 12, 2011 at 3:15 am #54124
John A. Wilke
Participant
Guys, rather than using those big honkin’ eyenuts, I have some hardpoint anchors in 1/4-20. They are identical to the anchors that came with the KestreL except the threaded core is 1/4-20 (same length, OD, cross-hole, etc.)

The 1/4-20 anchors are $4.50 ea. I think I have a half-dozen or so….

The KestreL doesn’t have a whole lot of room in that area – that is why I made these anchors.
April 12, 2011 at 4:57 am #54125
John A. Wilke
Participant
The 1/4-20 anchors are sold out 😯

I will have some more made in the future…

JW
April 12, 2011 at 2:26 pm #54126
SCOTT EVANS
The 1/4-20 anchors are sold out 😯

I will have some more made in the future…

JW

So….I guess its back to “using those big honkin’ eyenuts” 😉

A guy could go down to ALRECO and get some bar stock and in 1/2 hour with a drill(drill press would be better) and tap make himself 1 or 10
April 12, 2011 at 5:16 pm #54127
BEAR
Forgive my ignorance, but why not go to Ace Hardware and get a short 1/4-20 eyebolt, cut the threads to the length you want, put a jam nut on it and call it good. Would that not do the same thing and be pretty quick and in-expensive? If I am wrong, would someone please educate me.

Remember, if the women don’t find you handsome, at least they will find you handy!
April 12, 2011 at 5:41 pm #54128
John A. Wilke
Participant
Yep – you could do that. There is some extra weight, and eyebolts tend to open up (seen it happen many times). You could, of course, weld it.

The advantages of the anchors are they are smaller and lighter. This particular area in a KestreL is way very, very tight – so something a bit more svelte is good. On larger rockets, you are right on (as long as you weld it shut)
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