Redline? What redline?

[flyboycpa]

General topic of curiosity here, whether it's F-1, Bipe, Sport, Super Sport, Jet, Unlimited...doesn't matter.

How close to the placarded redline are the racers running typically?

Over redline? Just under? If so, are the pilots at all concerned with the effects of the turbulence and G's on the airframe?

This just came to mind watching Scotty's new Unleashed video and noticing the ASI so close to the red. Also, I just ferried a highly-modified Globe Swift that will cruise 24"/2400 rpm at 180mph (only 5 mph below redline) and while enroute this past weekend I picked up some not-so-mild turbulence and ended up pulling the speed waaaaay back (back to the green) to try to take care of the gentleman's airplane.

Just curious of y'all's thoughts on the subject.

Sam

[team zipper]

Re: Redline? What redline?

In my formula one and biplane experience, if after crossing the finish line, if the oil temp, cylinder head temp and others are not over the redline, you are not trying hard enough.
It's like running a marathon. If there is no blood in your urine the next morning, you did not try hard enough.
We run the O-200s at 4200 rpm and the IO360s at 3300 rpm, WAAAYYover redline.
redlines?, we don't need no stinkin redlines!
...TEAM ZIPPER AIR RACING

[flyboycpa]

Re: Redline? What redline?

Yeah, you're right....

I probably should have qualified the question a little better, as I know the engine is assumed to get flogged beyond redline in rpm and temps.

Specifically, I was questioning how much over redline airspeed folks feel comfortable running during a race.

We all know when we are trained as newbie Private Pilots to keep it in the green arc during turbulence, but how much banging around during the race while in the yellow arc, or beyond redline, is ok before worrying about deformation, delamination, shedding pieces, etc.?

I hope nobody takes these questions as criticisms, I'm not a hater, I'm just jealous that I'm not up there yet myself running beyond the limits.

Sam

[Scotty G]

Re: Redline? What redline?

Well, our slogan in 2006 was "Redlines aren't limits, they're targets."

But airspeed is a little different animal, especially for an airplane like Unleashed. You have to flight test and see if you're going to have a problem with control flutter. The other things you think about; dynamic pressure ripping off something that isn't used to seeing that kind of speed/pressure, or something that's been weakened over time and is ready to fail.

And what about the things we already know about? The faster you go, the more the center of lift moves aft. (Not any deal with Unleashed, but you get into some really fast airplanes and you start to have problems.) Wing torsion with control use, G load under rolling loads, etc, etc, etc.

In most cases, smooth air and redline airspeed at the race start isn't that big of a exposure to risk in my eyes. Unless, of course, it's bumpy as hell. Now you introduce G spikes at extremely high airspeeds and you could have a problem .2 seconds later.

So, how bad do you wanna race, and how fast do you wanna go?

Airplanes like the P-51, Sea Fury, and probably the NXT and Darryl's Legacy are designed for these types of speeds. Actually, most of the WWII stuff is way overdesigned.

Engine limits; I'll leave that to the pro's like Barrow, Chiavetta, and how to handle them: Eldridge!

[Dudewanarace]

Re: Redline? What redline?

In regards to Unleashed..

As per the Lancair operators manual, Vne is 273 mph. Best average race speed this year was 263.909.

Then you have the discussion about indicated versus true airspeed, and what is the published Vne based on.

Pre-Reno testing I took the airplane to indicated Vne at a pretty good altitude, thus true airspeed was well beyond Vne with no noticable problems.

I know of an RV-7 that had rudder flutter below indicated Vne, but above Vne true airspeed. Lucky to be alive. For that reason, I'll stay the hell away from a Harmon Rocket thank you very much.

[Mluvara]

Re: Redline? What redline?

The P-51, in a stock configuration, has a Vne of 505 indicated. None of the racers are doing 505 indicated on the course. I actually saw the highest telemetry data that I have ever seen this year at 481 IAS on the start in Voodoo. Obviously, this is a modified airplane, much away from the stock configuration and one would have to go look at what the North American engineers set as a safety factor and what they thought the issues you would see were past Vne.

Czech Mate I believe is significantly over Vne (somewhere around 410).

Michael

[Race5]

Re: Redline? What redline?

The P-51, in a stock configuration, has a Vne of 505 indicated. None of the racers are doing 505 indicated on the course. I actually saw the highest telemetry data that I have ever seen this year at 481 IAS on the start in Voodoo. Obviously, this is a modified airplane, much away from the stock configuration and one would have to go look at what the North American engineers set as a safety factor and what they thought the issues you would see were past Vne.

Czech Mate I believe is significantly over Vne (somewhere around 410).

Michael

Makes you wonder what kind of speed Strega was making. He wasn't just blasting away from Voodoo, but was definitely pulling out on him.

[shorebird]

Re: Redline? What redline?

Any Pitts running over 203 mph is operating over Vne. DragRacer #25 and Norm Way's Magic are 20 to 30 mph over Vne when turning into pylon #4.

[AirDOGGe]

Re: Redline? What redline?

In regards to Unleashed..

As per the Lancair operators manual, Vne is 273 mph. Best average race speed this year was 263.909.

Is that true for a Lancair 3? I ask because Jeff Lavelle did much faster TOP speed.

Quoted from a recent flying-related article at Aero-news.net:

Flying his Glasair III at the 2010 National Championship Air Races in Stead, Nevada, Jeff Lavelle set a blistering new Sport Class qualifying record, setting the bar up at 362.481 MPH.

If so, then that's quite a jump beyond the "redline". Whew!


.

[wingman]

Re: Redline? What redline?

There are several quite different Lancair models (but there is not a Lancair 3), and Jeff Lavelle was not flying any of them...

[stuntflyr]

Re: Redline? What redline?

Any Pitts running over 203 mph is operating over Vne. DragRacer #25 and Norm Way's Magic are 20 to 30 mph over Vne when turning into pylon #4.

Any fixed pitch S-1 entering the box at less than 203 mph and 3300 rpm isn't trying!!! Typical aerobatic contest fare.
Chris...

[AirDOGGe]

Re: Redline? What redline?

There are several quite different Lancair models (but there is not a Lancair 3), and Jeff Lavelle was not flying any of them...

Ok, AirHEAD here (me) confused Glasairs with Lancairs. Lemme see what I can find...

(looks up the info...)


Glasair III - Glasair Aviation
Never Exceed Speed (Vne), 335 mph / 291 knots


So he was only 30 knots over redline as well. That makes more sense. Thanks for the correction.

[flyboycpa]

Re: Redline? What redline?

Czech Mate I believe is significantly over Vne (somewhere around 410).

Michael

This point by Michael really hits the nail on the head of why I was asking the question. As we all know, our own Bucky captured the images of Czechmate this year and arguably saved us from a potentially really-bad outcome had the wing decided to bid adieu.

Particularly in the Pitts, it seems that running over is fairly common. Are there any common items that seem overly fatigued afterwards (fairings, strut attachments, etc.)?

Sam