# highest flight

#### TRFfan

##### Well-Known Member
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

##### Well-Known Member
There isn't a set maximum altitude since air density, humidity, etc. will vary.

#### CoyoteNumber2

##### Original San Diego High Power Rocketry
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

##### Rocketeer in MD
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

##### Well-Known Member
There is a flight record that cannot be beaten: infinity. But that doesn't help much.

#### TRFfan

##### Well-Known Member
I mean a completely optimized rocket.

#### Incongruent

##### Well-Known Member
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

##### Well-Known Member
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

##### Well-Known Member
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

##### Well-Known Member
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.

#### Incongruent

##### Well-Known Member
But using today's tech you can still get some decent altitude.

Completely optimized is more than just decent.

#### GregGleason

##### Well-Known Member
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

#### OregonBAR

##### Rocketeer
TRF Supporter
There is a flight record that cannot be beaten: infinity.

Oh, I thought Buzz Lightyear beat that record

#### markkoelsch

##### Well-Known Member
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 &#128512;

TRF Supporter
Hehe. +1

#### tim cubbedge

##### Well-Known Member
Staff member
Global Mod
I do see one record being set for certain- the most threads started by a single user about related topics &#128512;

&#128515;

+2

#### Charles_McG

##### Ciderwright
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

##### Well-Known Member
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

##### Ex-Jaywalker
TRF Supporter
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

##### Well-Known Member
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

#### Steve Shannon

##### Well-Known Member
TRF Supporter
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?

In that case the altitude would be infinity.

#### CoyoteNumber2

##### Original San Diego High Power Rocketry
In that case the altitude would be infinity.

Even if the motor still has mass?

#### dhbarr

##### Amateur Professional
TRF Supporter
Even if the motor still has mass?
Spherical cows in a vacuum, my friend.

#### Steve Shannon

##### Well-Known Member
TRF Supporter
Even if the motor still has mass?

It's not possible for the rocket in the original question to have no mass if the motor has mass.

#### CoyoteNumber2

##### Original San Diego High Power Rocketry
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 &#8220;the limit to how high [a] motor can go&#8221; in a &#8220;completely optimized rocket.&#8221; What do we do to optimize a rocket? We make it lighter and more aerodynamic. Ergo, a hypothetical &#8220;completely optimized&#8221; rocket would be massless and dragless, with the motor only lifting its own weight.

At least that's my take on it. It&#8217;s just a thought experiment.

#### watheyak

##### Ex-Jaywalker
TRF Supporter
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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#### CoyoteNumber2

##### Original San Diego High Power Rocketry
For rockets smaller that K impulse you have to ADD mass for maximum altitude.

Excellent point, I hadn't considered that for smaller rockets.

#### Steve Shannon

##### Well-Known Member
TRF Supporter
Excellent point, I hadn't considered that for smaller rockets.

But that is only because of drag. In the scenario you proposed there was no drag.

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