} In article , snipped-for-privacy@aol.com (RayDunakin) writes: } > put the total in the H range, could I? >>
} > } > No. You have to use an H or I motor for Level 1 certification; a J, K, or L } > motor for Level 2, and an M or N motor for Level 3. However, you can fly the
3 } > G cluster without any certification. } } Incorrect! A 3 G cluster would be over both the propellant and total impulse } limits of a model rocket. It would in fact be a complex high power rocket. } } A 2 G cluster could be a model rocket.
I'm not sure what that means then. Does it mean I can't L1 qualify using 3 Gs totalling over the H lower limit, but I need an L1 to fly them?
I'm not defending the rule as it it stands, but I think I see how the disconnect happens... one has to demonstrate the use of a "High Power _Motor_" (i.e., H or larger), to obtain the certification which one is expected to hold in order to fly a "High Power Rocket" (which is defined in such a way that some rockets which use no "High Power Motors" may still be considered "High Power Rockets").
It is this aspect of the structure of the rules, for better or worse, that gives rise to the apparent anomaly noted here.
} In article , } David Weinshenker wrote: } } > I'm not defending the rule as it it stands, but I think I see how the } > disconnect } > happens... one has to demonstrate the use of a "High Power _Motor_" (i.e., H } > or larger), } > to obtain the certification which one is expected to hold in order to fly a } > "High Power } > Rocket" (which is defined in such a way that some rockets which use no "High } > Power Motors" } > may still be considered "High Power Rockets"). } > } > It is this aspect of the structure of the rules, for better or worse, that } > gives } > rise to the apparent anomaly noted here. } > } > -dave w } } The original rule (unsophisticated) was fly an H get approved. } } The new rule is more complicated than that but not much.
I emailed NAR and asked for clarification. The answer was that policy has been set which allows single engine flights for certification only. This is at odds with the rules on the web p0age. However, the rules page was last updated in 2001. Perhaps the rule has changed since, but the page hasn't. I've asked for clarification. If this stands, it makes the question moot (although still illogical; for that matter the problem could exist with three 55 ns F engines).
Ah well, it's a only bit of a distraction to have to build a single engine bird to fly just to keep working on this design.
} I emailed NAR and asked for clarification. The answer was that policy } has been set which allows single engine flights for certification } only. This is at odds with the rules on the web p0age. However, the } rules page was last updated in 2001. Perhaps the rule has changed } since, but the page hasn't. I've asked for clarification. If this } stands, it makes the question moot (although still illogical; for that } matter the problem could exist with three 55 ns F engines).
Correction, certification attempts MAY use clusters. Crap. This eats my lunch. Rules should make sense, especially when they're supposed to be so safety oriented.
They DO make sense from a different perspective...
Let's just say that you did cert for HPR by using a cluster of non-HPR motors. You'd be certified for something that you had not done! (like a driving test with no time in a motorized vehicle! "But I got my bike up to
30 mph, and obeyed the traffic laws!").
Trust me when I say that there is a difference between flying a SU G, or even a consumer G reload (G64), and a H123,H242, etc. motor. It's a minor difference to some, and a biggy to others. I've done probably conducted on the order of 50 L1 certs.
Using the "clustering into a power range" argument, it would be possible to use something as small as A motors! (yes. you'd need a BIG cluster!).
Build your bird so that it can fly a single H128 (29mm) or 3 G64's. Cert on the H-128, and you're in. There's no sense on making the actual cert flight more complex than required. And BTW, it's "for safety", that clusters (in general) are discouraged when doing certs.
Yup. For certification, you CAN cluster, but ONE MOTOR must be in the appropriate category (H or I for L1), and the total must still be within the category. So you could cert with a 2 H cluster, an H or small I with a couple E or F motors, etc. But not with a 3 G cluster.
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!
Actually, the original TRA rule was "fly any HPR motor and get certified for all HPR motors". Theoretically, one could have certified with an M motor. Or a 161ns H motor. But back then motors weren't even tested, so no one really knows what the H89 motor I certified with was. Maybe a low H, maybe a high end G.
And in the original NAR system, you flew a G to get H certified, then an H to bet I certified, etc. and clustering WAS allowed. I know someone who certified under those rules flying a 3xD12-0 CHAD staged to 3xD12-7 rocket.
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD!
} They DO make sense from a different perspective... } } Let's just say that you did cert for HPR by using a cluster of non-HPR } motors. You'd be certified for something that you had not done! (like a } driving test with no time in a motorized vehicle! "But I got my bike up to } 30 mph, and obeyed the traffic laws!"). } } Trust me when I say that there is a difference between flying a SU G, or } even a consumer G reload (G64), and a H123,H242, etc. motor. It's a minor } difference to some, and a biggy to others. I've done probably conducted on } the order of 50 L1 certs.
My 3G cluster IS HPR. I must have L1 to fly it. Yet I can't certify with it.
} Using the "clustering into a power range" argument, it would be possible to } use something as small as A motors! (yes. you'd need a BIG cluster!).
Reducto ad absurdium of a valid point does not invalidate it.
} Build your bird so that it can fly a single H128 (29mm) or 3 G64's. Cert on } the H-128, and you're in. There's no sense on making the actual cert flight } more complex than required. And BTW, it's "for safety", that clusters (in } general) are discouraged when doing certs.
I can't build this bird for both ways. The entire airframe is a 3 cluster tube. Far easier, and as it will happen, to build a single H capable bird for certifying. Getting the cert is no problem. As I said before, my problem is with illogic.
The rules state clustering is allowed. I've seen nothing discouraging it.
} In article , Doktor DynaSoar writes: } > I'm not sure what that means then. Does it mean I can't L1 qualify } > using 3 Gs totalling over the H lower limit, but I need an L1 to fly } > them? } } Yup. For certification, you CAN cluster, but ONE MOTOR must be in the } appropriate category (H or I for L1), and the total must still be within the } category. So you could cert with a 2 H cluster, an H or small I with a } couple E or F motors, etc. But not with a 3 G cluster. }
Unbalanced thrust seems dangerous to me. Surely this WOULD be discouraged, no?
Are you sure about this? I haven't checked but, I think that is ok to fly without a L1 cert enven though the impluse is in the L1 range. Maybe double check this with NAR.
or a config with a center 29mm and three other 29mm spaced evenly around it (6 would actually be the ideal fit!), fly on the center-only for the cert, and the 3 around it for a 3-G cluster. Remember to plug the unused MMT's as you want to contain the ejection charge!
You made me do it - I looked it up. NAR didn't seem to be have much info. Here's the TRA stuff which does say you must use either an H or I for a L1 flight. I think I saw something somewhere about no clusters for certs. On the NAR page, it looks like a cluster is ok. TRA doesn't mention it so, I guess a cluster is ok with them too. I wouldn't sign off on a cert flight unless it had an H or I even if it had 3 G's.
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Do I Certify Level 1?
This is the classic chicken and the egg (which came first?) scenario. How do I get certified if I cannot buy a motor? First to get certified the person wishing to obtain certification must be an active member of the Tripoli Rocketry Association, Inc. This can be accomplished by sending in an application with the appropriate funds or applying at a launch using the Temporary Membership Application (other than large national launches a person wishing to sign up at a launch should contact the prefect of that launch and let them know you will be joining so that they bring the appropriate forms).
To certify at level 1 requires a successful flight of an H or I rocket motor. You must contact the prefect before the launch and prearrange with the prefect for the purchase of an H or I motor. Most dealers will sell you an H or I motor if it is to be sent directly to the prefect for your certification launch. At a large regional launch where a rocket dealer is on site, the prefect can go with you to the dealer where you can purchase the motor for your certification, but the motor is given to the prefect who will then witness you assembling and prepping the motor for your certification attempt. Tripoli members are now allowed to certify level 1 with H or I hybrid motors (by board vote at LDRS 2000).
When ready to launch the rocket, fill out the flight card and add in the comments "CERTIFICATION LEVEL X" (where X is 1, 2 or 3). This will notify the LCO (Launch Control Officer) to announce that this flight will be a certification attempt, getting the attention of the person that will certify the flight (prefect or authorizing person) and if deemed necessary by the RSO (Range Safety Officer) to call for a "Heads Up" launch.
The authorizing person is watching, the rocket is launched and the flight is perfect, i.e. parachute is fully deployed, rocket is safely recovered, the motor did not eject out of the rocket and the rocket IS FLYABLE AGAIN WITHOUT reconstruction or modification, then the authorizing person will sign the 3 part form or Temporary Membership Form signifying that the certifying person witnessed the flight and its safe recovery. The MEMBER then sends in the appropriate page from the multi part form to headquarters. After the form is signed, the member may purchase motors applicable to the certification level attained.
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