How Much Altitude Is Gained In A Zoom Climb?

[Andy Bush]

I ran across this web site recently...it had a conversion formula for figuring altitude gain in a zoom climb. Here it is:
 http://aviation.wmich.edu/aero/htm/energy.html

Multiply 9 times your airspeed times your airspeed loss in hundreds of feet. The reference uses knots...I think we can disregard the difference between mph and knots for the sake of simplicity.

For example, you are at 300mph. You decide to pull up until you slow to 200mph.

Multiply 9 x 300 x 1

Altitude gained equals ~ 2700 feet.

Should be interesting to see if this works out in AH.

Andy

[Zigrat]

you should use

[v(i)^2-v(f)^2)]/(2g) = h

not 100% accurate because of thrust and drag , but if you assume that for the zoom thrust ~ drag (not the best assumption)

for a zoom 300 to 200 mph (437 ft/sec to 292 ft/sec)
(437^2-292^2)/64.4=
1641 ft gained

this will be under-estimating it since thrust only equals drag in steady, unaccelerated flight. but the effect should not add too much more (mabye 20%)unless it is a very high horsepower to weight aircraft (ie 109 g10)

[juzz]

Yeah, what Zigrat said.   Oh and lift isn't factored in either.

[This message has been edited by juzz (edited 11-09-2000).]

[wells]

For V in mph and h in feet, you can use

V^2 = 30h

or as a variation of zigrat's formula,

h = (Vi^2 - Vf^2)/30

[juzz]

Uhh Wells, 100^2 <> (300^2 - 200^2)  

[Glasses]

 Yeah ,yeah,yeah just consider me brain offcially fried...I mean what the heck are you lads thinking....jeez!

------------------
Glasses---I may have 4 eyes ,but you only have one wing.

[Nath-BDP]

hi

[wells]

yeah juzz, a zoom from 100 mph isn't gonna get you very far!

[tssfka]

 

Originally posted by Zigrat:
you should use

[v(i)^2-v(f)^2)]/(2g) = h

not 100% accurate because of thrust and drag , but if you assume that for the zoom thrust ~ drag (not the best assumption)

for a zoom 300 to 200 mph (437 ft/sec to 292 ft/sec)
(437^2-292^2)/64.4=
1641 ft gained

this will be under-estimating it since thrust only equals drag in steady, unaccelerated flight. but the effect should not add too much more (mabye 20%)unless it is a very high horsepower to weight aircraft (ie 109 g10)

Zig,

You're forgetting that kinetic energy is equal to 1/2*m*v^2.  ie you need to include the change in mass due to the fuel burn...  

(Yes I am being facetious)

[funked]

tssfka lol!

[Andy Bush]

Thanks folks...

I don't get anything close to the web site numbers...only about 60% or so. But I get a little more than what your formula comes up with...typically about 30% better or so.

I tried a Nik and a Yak at 50% fuel. I was surprised to note the difference between a hard pull (just below the onset of blackout) and a 3G pull...a considerable increase at the lower G.

Now I didn't try to be super-scientific in my trials...just wanted to get a feel for the numbers.

My one big conclusion is that I have been pulling way too many Gs when I pull up!

Andy

[eskimo]

Andy, you write some great stuff.
Thanks.

Whats your handle in AH?


eskimo

[Andy Bush]

Eskimo

Hi!  Thanks for the compliment!

As for my AH call sign...that's a fair question and deserves a fair answer.

Like some other folks that write professionally for our hobby, I choose to fly anonymously on-line.

Not that I am trying to hide anything! My sign on name in these forums is my real name...I'm in the phone book in St Louis, and my AH profile has as much info as I can put in it.

I fly DC-9s out of St Louis and you all are invited to stick your head in the cockpit and say hello anytime!

I don't mind being high profile in these forums...but when it comes to turnin' and burnin' for fun...well, I'd like to be just one of the thundering herd!

Andy

[gospel]

Yes, Andy you are certainly entitled to your annomymity.

Thank you for writing the great articles at simhq!   Please write more  

I appreciate your helpful and informative posts here on the bbs too.

Oh, Zig & Wells & funked, & all you other engineering types   : I appreciate your engineering expertise, your input helps to shape aces high's high fidelity flight model!
S! gospel
332nd flying mongrels

[This message has been edited by gospel (edited 11-10-2000).]