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Why isn't FAA waiver altitude determined???

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JMX

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Lots of frustration trying to reconcile this. It doesn't make much sense.

Somebody can stick a 125gram propellant H motor in a minimum diameter rocket and go over a mile high. OVER 5280 feet high but you can't launch a bigger I or J motor heavier rocket to 3,000 or 4,000!?!?!?


Why isn't it determined by altitude?

Why is it determined by propellant weight?

I know for a fact a well engineered min diameter rocket can go like 7,000 feet with a motor that doesn't require a waiver. A long burn H motor with 125grams of propellant will get you there.

But yet I can't launch my 20 lb J motor slow and low starship to 2500ft.

Why did they decide to go with propellant weight of all things?
 

rharshberger

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Propellant weight is only one determining factor among others as to whether you need a waiver, 1500grams rocket max weight is another, occupied structures within X distance and air traffic concerns are more considerations on how high the waiver can be.

Look at FAR 101 sect 101.23 actually a FAR 101 designates rockets that do and don't require waivers, when they are required and what notifications are required. The FAA also determines exactly what the waivers altitude will be if required.

The rockets falling below the requirements for a waiver are considered not hazardous to aviation as it has been explained to me (right or wrong, but thats one of the reasons I was told).
 

dhbarr

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I suspect part of the reason may be that altitude-in-flight is not directly observable and therefore fairly difficult to enforce.

Granted I know of no case where a rocket has been seized & weighed, but IMO that speaks more to the good citizenship of most rocketeers ( contrast with lasers, quadcopters ).
 

OverTheTop

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The amount of energy in the motor comes into it. If something goes wrong there is more energy there to be dissipated in other objects, especially if it does something like goes unstable as it leaves the rail. LIkewise with heavier rockets they can impact the ground with more energy when they have a recovery failure (about 73% of all failures I think I read somewhere, so quite a likely scenario). It's not the fall that kills you it is the sudden stop at the end ;). How much energy is there to dissipate on another object?
 
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