Cheyenne Driver

Is there a formula for calculating Climb Gradient's ?

At least get you in the ball park for determining your FPM on climb out.

I got the Pt. 23 and 25 info. just would like to see how you are all figuring this Climb Grad. out.

If DP calls for a certain Alt. climb per. NM. until reaching a specified Alt. Or if it calls for a certain Climb Grad. in % ( like 3.2%) assume you know what your ground speed will be. Do you need to look at Jepp. chart (gradient chart) or is there another way.

I apologize if this has been said before. I'm new to site and you guys have lots of great answers.

jetjockee

Try this-

Ft per NM divided by 6000 times 100, this will give you the Climb Gradient..

500
----- X 100 = .0833333 X 100 = 8.33% Climb Gradient
6000

500' = Ft per NM

6000' = How many feet in a NM ( I believe its 6032' per NM, I just round it off )

OmahaPilot

Rise over Run x 100

Cheyenne Driver

Your, Ft. per NM Divide by 6000 X 100 will give you your FPM that you'll need on VSI. If you change the x 100 to x 200 that will still give you the FPM except you are now at 200 kts GS.

So looks like you are multiplying by what the GS will be. That will get you the FPM.

Thanks for the answer, got me to think about it.

Cheyenne Driver

This appears to be a nice easy formula. Can you give an example?

Or if you have a min. climb of 500' per nm to 1500' and your GS is 150kts. how would you calculate?

Thank you.

geosynchronous

500 feet per nautical mile divided by 6076' (one nautical mile) x 100 will give you the required climb gradient.

500/6076x100= 8.23%

Take your gradient times your groundspeed to get a climb rate in feet per minute

8.23x150= 1235 feet per minute

FlyinFoSheezy

This is a good site with lots of info: Aviation Rules of Thumb - Flightsim Aviation Zone - Number 1 Flight Simulation & Aviation Resource! - Flight Simulator, Aviation Databases

Gives many memory items that are helpful.

edznaz

Nice link! You get a gold star IMHO. Thanks!

skyward80

Another way you can do it is to take 500 feet per nm multiplied by your speed in nm per minute. 150kts is 2.5 nm per min.

500' per nm X 2.5nm per min = 1250' per min.

Don't forget that for larger climbs, your true airspeed will increase even though your calibrated/indicated speed remains constant.

TAS can be computed from Indicated Airspeed (IAS). TAS increases over IAS at the rate of 2 percent per 1,000 feet altitude increase. So, use the
equation:
TAS = IAS + (2% per 1,000 feet) (IAS)

Here's a nice resource available to anybody and I highly recommend it.

http://www.e-publishing.af.mil

There is a search function in the upper right. Type in "11-217" without the quotes. Make sure you have publications selected then click search. This returns two hits. Select 11-217V2 (V1 is all the boring stuff USAF folks must comply with), go to page 69 in V2. It's a great explanation of the 60-to-1 Rule and has a bunch of formulas.

Skyward80

Cheyenne Driver

Thanks guys. Got it figured out. Just getting some of the possible tech. questions answered (studying).

CD