In another thread the turn rates of the Yak-9U came into question.
Several suggestions on the turn characteristics and ways to test its sustained turn rate versus the published data were brought up. Including direct testing against the La-5fn. So I conducted the testing this afternoon, and my test method is posted below.
In short, both the La-5fn and the Yak-9U seem to have approximately a 15-20% difference between their published turn performance and my AH testing.
The La-5fn has a published 360 degree left turn time of 19 seconds. In my AH testing the La-5fn produced 22.27 second average turn times to the right, and 22.59 second average turn times to the left with 100% fuel. With 50% fuel (it was suggested by Funked that the published data was with 50% fuel) the average times were 21.08/21.52 respectively.
The Yak-9U has a published 360 degree right turn time of 20 seconds. In my AH testing the Yak-9U produced 24.37 second average turn times to the left, and 24.04 second average turn times to the right with 100% fuel. With 50% fuel the average times were 23.84/23.32 respectively.
Raw Data
So in conclusion, if you compare the published figures versus my test data, the Yak-9U is between 14%-16% too slow in turn rate, depending on which is the correct tested fuel load. And the La-5fn is between 10%-15% too slow in turn rate.
I'll let you guys decide if you think this is a significant error or not.
What do you think? Opinons?
Test Procedure:Tests were conducted with a digital stopwatch and were recorded to the hundreths of seconds. Aircraft was launched at field A6 with 100% fuel (or 50% if so marked), and climbed to 1,000ft. At 1,000ft., the aircraft was set to autolevel and throttle was adjusted till 175IAS was reached (and stabilized) and aircraft trimmed correctly for that speed. Once reached the aircraft was rolled 90 degree's, the stop watch was started, and the aircraft was turned thru 360 degree's, and the time recorded. Each test was conducted 10 times for both left and right hand turns. Extreme care was taken to make sure the turns were "flat" and at maximum possible turn rates (ie edge of stall). If the aircraft deviate from the starting altitude by more than plus or minus 100ft (150ft to the off torque side) this test was thrown, out and it was repeated. It should be noted that the "off side" turns (against the torque) were much more difficult to accurately measure since the aircraft was much more prone to porpoise thru the turn.
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Vermillion
**MOL**, Men of Leisure
"Real Men fly Radials, Nancy Boys fly Spitfires"