Are the Unlimiteds tested in 500-600mph speed dives to test their modifications?

[SkyvanDelta]

Steve Hinton Jr says in his radio interview at 6:05 that the airplanes are tested to a higher speed and G Force than what you would see on the race course. So how do they test the higher speeds? Take the plane to 15,000 feet and put it in a dive? How fast do they go in this higher speed testing?

Radio interview here: http://knprnews.org/post/pilot-share...reno-air-races

[Wild Bill Kelso]

Re: Are the Unlimiteds tested in 500-600mph speed dives to test their modifications?

In 2013 we were required to dive test to VNE on PM. Which is about 550.

[SkyvanDelta]

Re: Are the Unlimiteds tested in 500-600mph speed dives to test their modifications?

In 2013 we were required to dive test to VNE on PM. Which is about 550.

Can you give us an idea of how this takes place? How high do you go, angle of descent, do you have lots of power on during the descent or back off the power and let gravity bring speed, how long do you stay at this speed?

[Thom Richard]

Re: Are the Unlimiteds tested in 500-600mph speed dives to test their modifications?

The Vne on the P-51 is 505 mph IAS at sea level on a standard day and the MMO is Mach 0.77. It would be a really bad idea to exceed either one of these, regardless of airframe upgrades. None of the aircraft in Reno approaches these numbers on the course. The True Air Speed (TAS) is significantly higher than the IAS at altitude and higher temperatures, which is where we get Dago Red type lap speeds.

How you attain the speed, through the use of high power or by diving matters little. Obviously, beating on a engine to accomplish this makes little sense, so diving from 15,000' to 5,000' is the easy way to duplicate "race conditions" for testing. And, due to possible calibration errors, you should give yourself a little margin on the airspeed indicator. We had PM up to 562 mph TAS and Mach 0.74 in testing last year. At which point we completed flutter testing and high G verifications. 7.5G's I believe (if my memory serves me right) we pulled at that time. The airframe was solid as could be. Definitely a confidence builder in the machine.

And yes, you do need special permission to exceed 250KIAS below 10,000'. Which of course we had. Its not that hard to get if you have a good relationship with the local FSDO and TRACON.

[TheRickster]

Re: Are the Unlimiteds tested in 500-600mph speed dives to test their modifications?

Here is an intersting talk done by Skip and he goes into detail about all the testing on Tsunami.. The flutter testing was funny although I am sure at the time it wasn't...