Aces High Bulletin Board

General Forums => Aircraft and Vehicles => Topic started by: Zigrat on March 21, 2001, 01:18:00 PM

Title: improved version of aircraft test spreadsheet available
Post by: Zigrat on March 21, 2001, 01:18:00 PM

hi
after hearing some testing reports i realized there were quite a few bugs/errors in my first version of the aircraft test spreadsheet

so i updated it with new data i got and corrected bugs found by niklas and others (thanks!)

this version should be about 95% accurate to what is actually happening in aces high, and if you find discrepancies of more than 10% then you might have cause for complanis about flight model. but errors less than that will be due to my generalizations to make it applicable to all different plane types.
 http://www.iit.edu/~buonmic/aircraft-test1.xls (http://www.iit.edu/~buonmic/aircraft-test1.xls)

Title: improved version of aircraft test spreadsheet available
Post by: Sable on March 21, 2001, 01:36:00 PM

Cool, a new version!   (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)

Sable
352nd FG

[This message has been edited by Sable (edited 03-21-2001).]

Title: improved version of aircraft test spreadsheet available
Post by: F4UDOA on March 21, 2001, 02:30:00 PM

Zig,

As usual excellent work.

Guess which plane I think is porked??

Title: improved version of aircraft test spreadsheet available
Post by: Zigrat on March 21, 2001, 03:10:00 PM

hi f4udoa


i think the f4u-1d produced 2000 hp military, 2250 wep right (at sea level)

loaded weight(100% gas and ammo, no external stores) of 12,039 right?

my sheet predicts atht in these conditions, under military, at sea level f4u climbs at at 3200 fpm at 180 MPH at sea level under WEP, and under military power climb at 2800 FPM at a best climb speed of 180 mph.

the aces high table lists, at sea level climbs of 3050 and 2700 in this loaded condition, which is a discrepancy of 4.9% under WEP and 3.7% under military power, which is within the expected error band of my program, so it really cannot be used as evidence either way, other than stating that it most likely supports the aces high model since its within the error band.

trying out the 190 dora, it yields a best climb speed of 4300 FPM at 188 MPH, which is 3.6% greater than that achieved in aces high. In general, after some testing, the program seems to over-estimate climb performance between 3-5% so id say that aces high FMs are generally quite accurate...

now if someone would like to go through all FMs and find if any discrepancies are over 5% then there might be an issue...

Title: improved version of aircraft test spreadsheet available
Post by: niklas on March 21, 2001, 03:11:00 PM

looks very good now, zigrat

Two proposals:
Add a row with a turn time for a full circle(simple: 360/turnrate)

Mark negative values in the Row "excess power" red like in the row "CL" - It´s easier to see when you hit a "sustained turn" (both red areas have to end in the same line, the next line would be the line for the sustained turn)

niklas

Title: improved version of aircraft test spreadsheet available
Post by: F4UDOA on March 21, 2001, 06:02:00 PM

Zig,

I use the performance numbers from the AH charts and the stall data from the pilots manual.

Combat HP=2250
Max speed SL=359
Landing weight=11,400lbs
Stall speed at landing weight=96mph
This weight and stall speed gives you a cl max of 1.48 which is accurate no flap.

This gives you a climb rate of
3449FPM at 180MPH on your spreadsheet

and at military power
2,000HP max speed at sea level 343MPH
Which gives gives you a climb of 2933FPM on your spreadsheet.

Check that against this actual flight test data and you are a genius. How about that!!

  http://www.geocities.com/slakergmb/id73.htm (http://www.geocities.com/slakergmb/id73.htm)  

Pretty compelling huh? The math and the source data all in one.

Picture wouldn't display, check the url.

[This message has been edited by F4UDOA (edited 03-21-2001).]

[This message has been edited by F4UDOA (edited 03-21-2001).]

[This message has been edited by F4UDOA (edited 03-21-2001).]

Title: improved version of aircraft test spreadsheet available
Post by: Zigrat on March 21, 2001, 07:37:00 PM

hi i used the listed weights, and a tested no flap stall speed of 100 mph at sea level no flap (cl=1.48) at the weight of 12175 and cd,0=.168

under wep, i get a climb rate (at this weight) of 3161 fpm at 181.6 mph


under combat power, i get 2690 fpm, again at 182 mph.

which are in both cses about 6-7% lower than those listed in your test reports, but they are greater than aces high performace by a small amount.

Title: improved version of aircraft test spreadsheet available
Post by: LLv34_Snefens on March 21, 2001, 07:43:00 PM

I get "ERR" in the turn columns no matter what data I try to enter. What am I doing wrong?

Title: improved version of aircraft test spreadsheet available
Post by: Zigrat on March 21, 2001, 08:24:00 PM

change the g loafing in the top middle, theres no turn performance at 1 g  (http://bbs.hitechcreations.com/smf/Smileys/default/smile.gif)

Title: improved version of aircraft test spreadsheet available
Post by: LLv34_Snefens on March 22, 2001, 01:48:00 PM

*slaps forehead*

DOH!

Title: improved version of aircraft test spreadsheet available
Post by: janneh on March 23, 2001, 12:28:00 AM

Nice job Zigrat !
I'm not familiar with this kind of data, but willing to learn tho.

Is there somewhere explanations for "CL,D,CD..." ?

Thanks in advance !