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View Full Version : Why no BT "G" load for 29/40-120 ??


ghrocketman
01-23-2007, 10:35 PM
Anybody happen to know why there is no Blue Thunder "G" load for the 29/40-120 RMS hobby case ?

Seems to me that a G80 or G90 RMS load would be great for that case.
I'd much rather have that than an "E" anything in 29mm as the 24/40 case holds full 40n-sec E's with BJ, WL, and BT propellant.
Now if Aerotech would just release Redline propellant in the Hobby-line cases.....

ghost
01-24-2007, 01:30 AM
Why don't Easy Access reloads work?
Like this one: https://www.discountrocketry.com/aerotech-g77rm-reload-p-1053.html?osCsid=7819bfc74d0657733ee043b49ac1a9d8

ghrocketman
01-24-2007, 09:09 AM
Because they are NOT designed for the 29/40-120 hobby-line case, they are for the High-Power 29-120 case.
Trust me it WILL NOT WORK !!!!
The grains, liners, and delays are different between the two cases.
Trying to use one in the opposite case WILL result in a CATO and a ruined, expensive case and rocket.

Initiator001
01-24-2007, 01:08 PM
Anybody happen to know why there is no Blue Thunder "G" load for the 29/40-120 RMS hobby case ?

Seems to me that a G80 or G90 RMS load would be great for that case.
I'd much rather have that than an "E" anything in 29mm as the 24/40 case holds full 40n-sec E's with BJ, WL, and BT propellant.
Now if Aerotech would just release Redline propellant in the Hobby-line cases.....

A Blue Thunder propellant load for the RMS-29/40-120 would exceed the NFPA rule that a 'model rocket motor' cannot have an average impulse greater than 80 Newtons.

As for Redline propellant for this casing, I wouldn't be surprised if AeroTech releases something this year (Unless it has the same 'problem' as a BT load, i.e., NFPA).

Bob

ghrocketman
01-24-2007, 03:05 PM
As usual, too many stinkin' un-needed regulations.
What about for those states that don't follow NFPA ?
How about under-rating it or only making it a G80 ?
G80 single use are ok, why could there not be a G80 reload ?

barone
01-24-2007, 07:17 PM
A Blue Thunder propellant load for the RMS-29/40-120 would exceed the NFPA rule that a 'model rocket motor' cannot have an average impulse greater than 80 Newtons.

As for Redline propellant for this casing, I wouldn't be surprised if AeroTech releases something this year (Unless it has the same 'problem' as a BT load, i.e., NFPA).

Bob

I'm I missing something here? I thought you couldn't exceed 160 newtons (a G motor). NAR still list those as certified for model rocket competition. Exceeding 160 newtons puts you in the high power rocket category. Of course, I'm looking at total impulse as opposed to average. I can fly two F motors (80 newtons each) to give me a full G (160 newtons) and still be certified for competition. If you'll notice, (http://nar.org/SandT/NARenglist.shtml) once you exceed the 160 newtons, the motors are no longer certified for model rocket competition but are still certified for HPR.

Carl@Semroc
01-24-2007, 09:02 PM
A Model Rocket Motor as defined can not exceed:
1. 80 N average thrust
2. 62.5 g of propellant
3. 160 N-sec total impulse

There have been several G motors over the years that have gone over these limits. All it has to do is go over on any one to be High Power.

None now are over the 160 N-sec, but several are over the 62.5G and/or the 80 N avg thrust.

Royatl
01-24-2007, 09:11 PM
Yes, you're missing something. Initiator001 was talking about average thrust, not total impulse.

80 newtons average thrust is the limit for a model rocket motor per National Fire Protection Association. The motor can have up to 160 ns of total impulse, but you have to limit its average thrust to 80 or under.

Now, the case itself is designed for only around 120ns. Right now, the White Lightning load is at 64 newtons ave thrust. Initiator001 is saying that a similar geometry BT load would probably break 80.

Shreadvector
01-24-2007, 09:23 PM
http://home.flash.net/~samily/stuff/HPR_metric8.pdf

Bookmark/Favorite.
Read.
Understand.
Print.
Share with others.

I'm I missing something here? I thought you couldn't exceed 160 newtons (a G motor). NAR still list those as certified for model rocket competition. Exceeding 160 newtons puts you in the high power rocket category. Of course, I'm looking at total impulse as opposed to average. I can fly two F motors (80 newtons each) to give me a full G (160 newtons) and still be certified for competition. If you'll notice, (http://nar.org/SandT/NARenglist.shtml) once you exceed the 160 newtons, the motors are no longer certified for model rocket competition but are still certified for HPR.

barone
01-24-2007, 09:26 PM
Yeap.....my bad. Caught on at Carl's post..... :o