Quantcast

Cesaroni Trouble

The Rocketry Forum

Help Support The Rocketry Forum:

Trenman

Well-Known Member
Joined
May 26, 2009
Messages
158
Reaction score
0
Forgive my ignorance in this matter. I have never used a reload before so I purchased a 38/120 1g motor to start out with. Below is pictured what I received.



My question: I am rather baffled by the delay instructions. I dont seem to have a drill holder or drill bit in the kit at all, yet instructions say to use them to set the delay function.



Honestly, maybe its because I dont have the parts, but the instructions seem vague. Could someone help me get on the right path? Cheers. L
 

quickburst

Well-Known Member
TRF Supporter
Joined
Jan 20, 2009
Messages
1,698
Reaction score
31
You need to buy the DAT (delay adjustment tool) tool. Your vendor should have it.

I'm assuming you have the motor case?
 

Trenman

Well-Known Member
Joined
May 26, 2009
Messages
158
Reaction score
0
Yes I have the case. Do I NEED to mess with the delay to pass my L1?
 

Bazookadale

Well-Known Member
Joined
Jan 18, 2009
Messages
1,318
Reaction score
0
Yes I have the case. Do I NEED to mess with the delay to pass my L1?
Well it's an 11 second delay - is your rocket light enough to safely deploy with that long a delay? If not you need to shorten it!
 

stickershock23

Never Fly Naked
Joined
Jan 18, 2009
Messages
4,180
Reaction score
236
I believe, BUT AM NOT CERTAIN, that The pro 38 delays can be shortened without the DAT tool, drill a hole 1/32" per second (about .030") that you need to remove from the propellant side of the delay.

Before you try this, someone from CTI please confirm that number.

Although I will say this, If you are going to fly any CTI reloads. the price of the tool is well worth it.

Good luck with you LI and enjoy!
 

Trenman

Well-Known Member
Joined
May 26, 2009
Messages
158
Reaction score
0
I ought to buy the tool. Everyone is sold out.... arghghhg
 

deandome

Well-Known Member
Joined
Jan 20, 2009
Messages
843
Reaction score
2
If you're launching w/a club of any size, SOMEONE will have one you can borrow.
 

Trenman

Well-Known Member
Joined
May 26, 2009
Messages
158
Reaction score
0
I'm sure thAt's the case but I've never done it before and I don't want to look completely stupid before my L1 cert for fear of not passing. I suppose I can just read and reread the instructions. I am quite sure it's a piece of cake for someone who has done it before. I never have but the instructions seem a bit vague.
 

stickershock23

Never Fly Naked
Joined
Jan 18, 2009
Messages
4,180
Reaction score
236
Once you have the Pro DAT tool in your hand, it will all make sense.
It is very simple. no O-rings to mess with no seals, no spacers no grains to install..... Nothing. quick delay adjustment, slap the closure in... done.

Good luck
 

Trenman

Well-Known Member
Joined
May 26, 2009
Messages
158
Reaction score
0
I'll ask for clarification: do I understand correctly that a 2G reload actually has 2 grains plus a delay grain? I think that's correct.

So my question: does the igniter go all the way through the 2 grains and into the delay or does one have to be careful not to put it that far up, instead letting it rest into the 2nd grain?
 

n3tjm

Papa Elf
Joined
Jan 21, 2009
Messages
7,381
Reaction score
226
Location
Penns Creek, PA
On the motors with the black poweder pellets, you want the igniter to go all the way up against the pellet. With the motors that dont have the bp pellet, you put the way up and then back it off about half an inch.
 

bobkrech

Well-Known Member
Joined
Jan 20, 2009
Messages
8,354
Reaction score
29
Trenman

1.) Read and you will understand the directions! The Pro38 is as easy as dirt to use. Look at the pictures.

2.) Follow the igniter installation directions exactly. The igniter must extend all the way up to the delay grain that has a black powder starter pellet built in. If you use the supplied nozzle cap, it will hold the igniter in place. When the supplied igniter is in contact with the delay unit, the motor will light instantly.

3.) When you get to the field, find someone who uses Pro38 motors. Get him to guide and watch you assemble the motor.

4.) Borrow a PRODAT. Sim you rocket with the actual as built weight and use a Cd of 0.6 and 0.75 to determine the motor delay required. PRO 38 motors have the maximum delay as part of the identifier, The ProDat delay drill remove delay time from the delay grain and the amount remove is indicated on the tool.

For example if you use a motor with -13A at the end of the designation, and you need a 6 second delay after burnout according from your sim, you set the tool to 6 - 13 = -7 seconds and drill out the delay until the tool bottoms out. It's really that simple.

5.) Make a check list of what you have to do before you go to the field and follow it. Check off each item when you do it and you won't have a stupid mistake wreck your cert flight.

6.) Take a deep breath, and relax. With the mentoring of an experience person, you flight will go well.

Good luck.

Bob
 

Jeroen_at_CTI

Well-Known Member
Joined
Apr 27, 2009
Messages
564
Reaction score
1
I believe, BUT AM NOT CERTAIN, that The pro 38 delays can be shortened without the DAT tool, drill a hole 1/32" per second (about .030") that you need to remove from the propellant side of the delay. Before you try this, someone from CTI please confirm that number.
Please use the delay tool. It is a lot more accurate and the same tool can be used for all Pro38 and Pro29 reloads (as well as Loki and AT and....).

The actual number is closer to 0.040" / s, btw.

Jeroen
 

stickershock23

Never Fly Naked
Joined
Jan 18, 2009
Messages
4,180
Reaction score
236
Please use the delay tool. It is a lot more accurate and the same tool can be used for all Pro38 and Pro29 reloads (as well as Loki and AT and....).

The actual number is closer to 0.040" / s, btw.

Jeroen
Most definitely, I was just curious to the number... XXXinch = XXX seconds

The tool is totally accurate.
 

MarkII

Well-Known Member
Joined
Jan 18, 2009
Messages
8,255
Reaction score
9
Instead of having to produce multiple versions of each Pro38 and Pro54 reload with different set delays, CTI provides all of them with the maximum delay installed. You can then shorten the delay to the interval that you require. Not a bad approach to the issue of providing the user with a range of delays for a given motor. I'm not as familiar with their Pro29's, but I suspect that they carry this feature as well.

MarkII
 

cjl

Well-Known Member
Joined
Jan 18, 2009
Messages
12,549
Reaction score
5
Correct - I'm pretty sure the 29's use the 38mm DAT with an adapter.
 
Top