highest flight

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TRFfan

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Has anyone ever got a record with a certain motor size that is the limit to how high that motor can go? A lot of the altitude records online look like they can be improved on but i was wondering if there was one record flight that cannot be beaten (like best fin shape and size, nose cone length, etc.).
 

Incongruent

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There isn't a set maximum altitude since air density, humidity, etc. will vary.
 

CoyoteNumber2

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If you had a hypothetical rocket with a mass of zero and a drag coefficient of zero, wouldn't that be the highest any given motor could fly?
 

Bat-mite

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A launch from Denver is going to go about a mile higher than from New York. :wink:

Seriously, though, lower atmospheric pressure at already high altitudes will get higher launches. There is no magic number for a given motor. Even if there were, motors have tolerances. Launch two AT G80s in the same rocket on the same day and one will go higher than the other.
 

Incongruent

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There is a flight record that cannot be beaten: infinity. But that doesn't help much.
 

Incongruent

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A completely optimized rocket will differ for different environmental conditions.

Example: With half the atmospheric pressure at ground level, the fins will have to be bigger than with the pressure at ground level.
 

TRFfan

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A completely optimized rocket will differ for different environmental conditions.

Example: With half the atmospheric pressure at ground level, the fins will have to be bigger than with the pressure at ground level.
At sea level.
 

RocketFeller

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I mean a completely optimized rocket.
There is no such thing in the real world. "Completely optimized" will constantly change as material sciences advance and better computational models arrive. Rockets built using titanium and carbon fiber may be "completely optimized" today, but tomorrow's technology will eventually make that rocket less than optimal.
 

TRFfan

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There is no such thing in the real world. "Completely optimized" will constantly change as material sciences advance and better computational models arrive. Rockets built using titanium and carbon fiber may be "completely optimized" today, but tomorrow's technology will eventually make that rocket less than optimal.
But using today's tech you can still get some decent altitude.
 

GregGleason

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I am certain that there is too much in the way of motor and atmospheric variance to say "This record will stand" with any kind of certainty.

Greg
 

markkoelsch

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In simple terms maybe. If you look at what Von Delius has done with his J record Flight one would be very hard pressed to beat it. That said, it may well be beaten at some point.

Complete optimization is a concept. Completely optimized tends to put rockets close to the edge in terms of stability. It is also completely motor dependent. What is optimal for a given motor will not be optimal for another motor.

I do see one record being set for certain- the most threads started by a single user about related topics 😀
 

Charles_McG

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If you had a hypothetical rocket with a mass of zero and a drag coefficient of zero, wouldn't that be the highest any given motor could fly?
To quote Heinlein: 'It stands to reason, you can't accelerate something that ain't got mass'
Rolling Stones (on why ghosts in the asteroid belt can't get home)
 

DavidMcCann

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Completely optimized would mean operating with zero safety margin. Every variance would have to go totally in your favor. When you start relying on things you can't control, that's luck, not design. At some point the question is "can I best that record?- well maybe if I'm lucky ". But not a reliable "yes"
 

watheyak

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You're teensy and simple triangle fins on your G rocket are far from an optimized or ideal shape if you want the least amount of drag. There's more factors at play than what the Sims are telling you.
 

new2hpr

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A launch from Denver is going to go about a mile higher than from New York. :wink:
Not AGL, but it will go higher.

If anyone holding a current record takes the same rocket and launches with Tripoli Colorado in Hartsel (elevation 8864'), they will go higher, assuming they're still stable with the thinner air!

Any club with a higher base elevation?
-Ken
 

CoyoteNumber2

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It's not possible for the rocket in the original question to have no mass if the motor has mass.
Of course the rocket and motor as an integrated system would have mass. TRFfan was asking about “the limit to how high [a] motor can go” in a “completely optimized rocket.” What do we do to optimize a rocket? We make it lighter and more aerodynamic. Ergo, a hypothetical “completely optimized” rocket would be massless and dragless, with the motor only lifting its own weight.

At least that's my take on it. It’s just a thought experiment.
 

watheyak

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For rockets smaller than K impulse you have to ADD mass for maximum altitude.

And the spherical cows in a vacuum must also be perfectly elastic. A minor detail, but important nonetheless.
 
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