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Andy Greene

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Im trying to convert comparable motors from the build sheet of one of my MadCow kits- the RMS motors listed are all AT- and I have a CTI case. CTI lists their specs of max thrust in lbs - and not all F- reloads is it even listed. AT lists theirs in NS -
So how do I know whats what ? Im looking at a comparable load for my CTI case as the AT -
E23T-5
F22J-5
F40W-7

Also is there anything else needed to fly 2g CTI loads in a 3g case , besides the spacer??
I have a Pro 29-3g

Any help would be appreciated.
 
The motors you listed are all AT Hobbyline 29/40-120 reloads. The comparable CTI loads would be the Pro29-1G reloads. If you want to fly the CTI Pro29-2G loads, then compare them to the G sized Hobbyline loads such as the G53FJ, G64W, and G71R, loads.

To compare lbs of thrust to N of thrust, multiply the lbs by 4.44882 to get N. If you multiply the N by .2248 you'll get the equivalent lbs. Of course you can divide the N by 4.44882 to get the lbs also.
 
Thanks guys- looks like I need 2 grain spacers, and yes I have the rear closure. Appreciate the help.
Now time to crunch some numbers- Looking for something for my MC Mozzie and keep it in the 800-1200 ft range . 1500 max
Most of the 1g CTI stuff seems to have really long delays times- Im lost on what way to go here.

EDIT- Duh delay tool - but where to cut it to ?


Andy
 
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the delays for CTI motors are adjustable. You'll need the PRO38 Delay Adjustment tool and a 29mm adapter for the tool. Then you can take 3, 5, 7. or 9 seconds off the posted delay. I've recently converted an large Easter Egg and fly it on CTI loads. With it's high drag I have to shorten the delay to 3 or 4 seconds.

You remove the delay element from the reload and drill out part of the delay element. Check out the CTI sites of get with someone who can show you how it workds.
 
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get openrocket, it is a free download and free to use. lets you sim the flights with just about any available motor. Search for a Rocksim file for your rocket on google and you are in business. gives you stability, speed, optimum delay and altitude.
 
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Thanks guys- looks like I need 2 grain spacers, and yes I have the rear closure. Appreciate the help.
Now time to crunch some numbers- Looking for something for my MC Mozzie and keep it in the 800-1200 ft range . 1500 max
Most of the 1g CTI stuff seems to have really long delays times- Im lost on what way to go here.

EDIT- Duh delay tool - but where to cut it to ?

Andy
For a rough estimate- I use a scale to get the total Loaded mass of the rocket-that's everything including parachute, case, paint, propellant, etc. Check out Mr. Coker's very excellent Thrustcurve.,org and run the very easy to use simulator. All the motor data is there. Check out the time to apogee for an initial idea of what to remove for your optimum (lowest deployment speed) delay. You can also see and try other motors for your rocket. And it's FREE! I never fly without it!
 
For a rough estimate- I use a scale to get the total Loaded mass of the rocket-that's everything including parachute, case, paint, propellant, etc. Check out Mr. Coker's very excellent Thrustcurve.,org and run the very easy to use simulator. All the motor data is there. Check out the time to apogee for an initial idea of what to remove for your optimum (lowest deployment speed) delay. You can also see and try other motors for your rocket. And it's FREE! I never fly without it!

Used it today and ave me a really good starting point- thanks again
 
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