shockie
High Plains Rocketeer
nevermind
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It would be very easy if that chart in post #13 had units, but it doesn't and the units I try don't give those numbers. Here's something I can stand by: http://rocketrycalculator.com/rocketry-calculator/thrust-to-weight-ratio/
So the online calculator is incorrect?That calculator I linked to includes "Gravity(".
Well that should be "Gravity(9.8m/s^2)"
It's up to the RSO.All I need to know is what does the RSO use at the check-in table?
Probably not.And (here's the tough part), do all RSO's use the same check using the same units?
Yes. 3:1 using the certified average thrust of the motor.In other words, are there TRA and NAR standards that all RSO's have to follow?
Probably not. But the higher your T:W, the more likely you'll get a "go".Will I get the same result (ok to go, or no) everywhere I go with the same rocket?
NFPA 1127, the NAR High Power Safety Code and TRA's Safe Launch Practices require that the certified average thrust of the motor be 3 times the total weight. But this is just a minimum. In the interest of safety, the RSO is free to require a higher thrust if he chooses, based on his experience and judgment. We trust the RSO is in a better position to determine the correct T:W ratio needed for the situation than the writers of the respective codes. The correct T:W is not one-size fits all, so the RSO has the final say, so long as the minimum is met.And if not, why not?
Thank you very much Funkworks!It would be very easy if that chart in post #13 had units, but it doesn't and the units I try don't give those numbers. Here's something I can stand by: http://rocketrycalculator.com/rocketry-calculator/thrust-to-weight-ratio/
... the RSO is free to require a higher thrust if he chooses...
I have to say that's one area of this sport that I dislike the most
It is what it is. But consider this from the RSO’s perspective. His job is to keep spectators, flyers and property as safe as he can while ensuring everyone has a good time. He has to balance between people having fun and keeping the club’s insurance intact.I have to say that's one area of this sport that I dislike the most
… As lakeroadster said, you can always fly on your own. Then you can be your own RSO. You just have to get permission from a property owner, a waiver from the FAA (for most HPR), and follow the respective safety code and the applicable regulations.
Yes. Ridiculous. No one has ever done it before. Gosh, how do the clubs do it?Which is a ridiculous suggestion.
My point is why so much variation from one to the next?
If it's safe, it's safe. If we have national standards, national organizations, why so arbitrary?
extra restrictive launch Nazi.
Which is a ridiculous suggestion.
My point is why so much variation from one to the next?
If it's safe, it's safe. If we have national standards, national organizations, why so arbitrary?
All I'm saying is I'd like to be reasonably confident after I spend weeks reading thru the standards/code, simulating, building and painting a rocket, that after I drive 3 or 4 hours to a launch, I don't get turned away because of an extra restrictive launch Nazi.
Which is a ridiculous suggestion.
My point is why so much variation from one to the next?
If it's safe, it's safe. If we have national standards, national organizations, why so arbitrary?
You must be very lonely....I don't talk to people who are "offended" by SI units. I just pity them.
It is only the dumb, recalcitrant US population that clings to feet, inches, and pounds.
I'm retired from a US manufacturer of high precision optical and electronic equipment. I never saw anything but SI units employed. It is only the dumb, recalcitrant US population that clings to feet, inches, and pounds.
Hi Scud-B,
The point is to work only in the metric system. That way no one ever has to convert out of it to any other system.
Stanley
You have a good point but you have not consider another reason why.......besides the safety code and regulations ........Unless there is a Specific law stating what can be and not be done....most everything is up to discretion. So base on Thrust to weight ratio.......your SIMs, actual flight data you can provide,, discretionary decision making is normal a expectation. As others have mention in other posts...you can buy a motor on site from a vendor that RSO make agreed with.All I'm saying is I'd like to be reasonably confident after I spend weeks reading thru the standards/code, simulating, building and painting a rocket, that after I drive 3 or 4 hours to a launch, I don't get turned away because of an extra restrictive launch Nazi.
What do you mean, please, that you were doing conversions between metric units?
Hi Scud-B,But generally, when I say conversions among metric units, I mean something like grams*cm/s^2 to kg*m/s^2. That's not one of the specific examples from my work, it's just a conversion within a measurement system.
I'm retired from a US manufacturer of high precision optical and electronic equipment. I never saw anything but SI units employed. It is only the dumb, recalcitrant US population that clings to feet, inches, and pounds.
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