PDA

View Full Version : Best Way to Test Planes



CarpeNoctem43
06-19-2007, 07:55 AM
I took a class over @ www.joint-ops.com (http://www.joint-ops.com) and they had us develop a flight envelope for the 1940 Zero. It was a real learning experience!

Basically, at various altitudes (1000m to service ceiling incrementing altitude) you recorded stall speed and max speed @ 100% power w/radiator settings that allowed you not to overheat.

After recording all IAS values, we developed a tab format file and coverted values to TAS. If you did it correctly, and didn't quit before you met the service ceiling (i got 11470m) you ended up with values that would plot out a very nice flight envelope.

How I did it was in a single shot, flew the Zero and climbed to each altitude.

I am now thinking there must be a better way. What technique do all of you use, if you record such things.

Also, what else can be tested and how? I.e. How could you test turn rate? How about Vx and Vy? i am really interested in finding best glide speed too.

Best regards,

Raven

CarpeNoctem43
06-19-2007, 07:55 AM
I took a class over @ www.joint-ops.com (http://www.joint-ops.com) and they had us develop a flight envelope for the 1940 Zero. It was a real learning experience!

Basically, at various altitudes (1000m to service ceiling incrementing altitude) you recorded stall speed and max speed @ 100% power w/radiator settings that allowed you not to overheat.

After recording all IAS values, we developed a tab format file and coverted values to TAS. If you did it correctly, and didn't quit before you met the service ceiling (i got 11470m) you ended up with values that would plot out a very nice flight envelope.

How I did it was in a single shot, flew the Zero and climbed to each altitude.

I am now thinking there must be a better way. What technique do all of you use, if you record such things.

Also, what else can be tested and how? I.e. How could you test turn rate? How about Vx and Vy? i am really interested in finding best glide speed too.

Best regards,

Raven

BBB_Hyperion
06-19-2007, 10:59 PM
For AI Data use IL2Compare. When you want to test yourself there are several conditions to monitor.

Each map has it's own density distribution.

You can extrapolate data from 1000 m to alt to some degree.

So IAS / TAS conversion is different for each map.

For own recordings you could use devicelink interface to check how good your turn was basically a human flown plane can't match best sustained turn cause you fly not that perfect.

On the other hand turntimes for sustained turns are pretty useless in df cause absolute no one uses them instead instant turns or combat turns are used bleeding energy to gain and break off when not gaining enough.

GerritJ9
06-20-2007, 03:44 PM
1C use the Crimea map when testing, so that is what I now use. I have to add, though, that I have found little difference when comparing test results on the Crimea map with results obtained on other maps.

AKA_TAGERT
06-20-2007, 04:17 PM
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by CarpeNoctem43:
I am now thinking there must be a better way. What technique do all of you use, if you record such things. </div></BLOCKQUOTE>
For recording things you have a couple of choices

UDPSpeed
UDPGraph

Here is an link that covers the usage of those utils

http://forums.ubi.com/eve/forums/a/tpc/f/49310655/m/7201027043

And if your interested in repeatable tests.. You may want to take a look at this autopilot util

http://lesnihu.wz.cz/autopilot/autopilot.html

In the read me of that util he talks about setting it up for turn testing.. I have not tried doing any turn tests yet, but I have used it for rate of climb (ROC) testing and top speed testing. I hope more people start using it than we build a data base of script files that we can all share.

Pigeon_
06-22-2007, 04:36 AM
So what about the good old paper, pen and stopwatch?

Turn rate

You can describe this in two different ways:

- Degrees per second (e.g. 150?/s).

- The amount of time it takes to complete a set turn ratio (e.g. 2.4 seconds for a 360 degree turn (full circle)).

To find the best turn ratio, you must also find the optimum turning speed. I would do this by flying the aircraft in multiple circles at a set speed (ofcourse, it's very difficult to maintain the exact same speed whilst flying multiple circles, this may need a lot of practise. Practise makes perfect though. http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif ). The more circles you fly, the more accurate your calculation will be. After completing a set of circles, you can calculate your turn rate for that particular airspeed.

For example, your airspeed was 180 kts and it took you 26 seconds to complete 10 full circles, the turn rate at 180 kts is 2.6 seconds for 360 degrees (= 138.5?/s). To make this calculation even more accurate, you should practise a few times first and then do multiple flights of 10 circles. After that, you can calculate the mean of the outcomes for more accuracy.

Now you only know the turn rate for 180 kts though... You have to experiment with different speeds to get the optimal turning speed and thus, the optimal turn rate. Start out by making a rough estimate of the optimal speed. If, for example, you think 195 kts is the optimal turning speed, try 190, 195 and 200 kts to see wich speed gives you the fastest turns. Then narrow it down to the optimal airspeed (Yes, this takes a lot of flying!). There's no need yet to be very precise in your calculations though. Just increase the accuracy of your calculations as you get closer to the optimal turning speed.


Optimal climb/glide speed (I don't know what you mean by Vx and Vy...)

Just start out at a certain altitude and measure how much time it takes you to ascend/descend to a certain altidue. Try this at different speeds and try to narrow it down to the optimum speed (the speed at which it takes you the smallest amount of time to ascend/descend to your target altitude). Again, the longer the flight (high altitude difference), the better the accuracy of your calculation will be. Also, you can repeat the flight at the same speed and calculate the mean of your outcome for even better accuracy.

Optimal climb/glide speeds my differ at various altitudes.


I hope this information will be of some use to you. Good luck! http://forums.ubi.com/groupee_common/emoticons/icon_smile.gif

Pigeon_
06-22-2007, 05:34 AM
You may also want to ahve a look at this site:

http://www.target4today.co.uk/ (link provided by Stuntie)

Click on 'Pilot's notes' to get an idea of the data you can accumulate from test flying.