What just happened at Reno?

[dbrown]

This audio is chilling as well, taken from what appears to be 10 rows or so from the impact site. Utterly chilling.



Video at the top of the page.

DB

http://www.tagesschau.sf.tv/Nachrichten ... kommentare

[TonyM]

Yep, that audio is chilling.

[spookythecat]

My thoughts are with my Cascade Warbirds group who were heavily effected by this. I know we lost some people and many were injured. Every year I hear how fun the Reno trip is and how I should come down. I would still consider it if and when the races commence. It still seems unreal to me.

[michaelharadon]

Interesting: http://www.azcentral.com/news/articles/ ... -ntsb.html

[Invader26]

aircraft retro-fitted with electric elevator trim system modified [as I'm reliably informed] from a GA type system...

[mr_warbird]

I believe in the late 90s there was another P-51 (could have been Voodoo) that also had the trim tab ripped off at Reno in a race. After that tore off, the aircraft went straight up for a 1000 feet, the massive G forces caused the pilot to black out. Fortunately the pilot regained his senses after a few moments and was able to land the plane without an accident.

I am quite certain we are seeing a similar failure here with Galloping Ghost. I believe the pilot probably blacked out right after the tab cam off when the aircraft bolted skyward pulling significant G forces, and may or may not have regained senses before the crash.

I do have a theory as to why we are seeing several P-51s losing trim tabs - momentary supersonic airflows over the tail surface. At 500 or so MPH, if a pilot makes an abrupt elevator movement, it is potentially possible to get a local increase in airflow over control surface which could exceed the speed of sound - this will cause shock waves and stresses for which the trim tab component (as well as the whole aircraft) were not designed to withstand.

If this turns out to indeed be the case, it will be interesting to see how the FAA responds. Basically, it could be the unlimited racers are operating so close to the sound barrier with the latest technology and modifications to P-51s that they are encountering momentary airflows and shock waves that the airframes were just simply not designed to support.

I really hope the Reno air races continue (this must be a difficult challenge for the organizers), it will be a very sad blow to the warbird, racing and aviation community as a whole if it is no longer allowed or too expensive as a result of increased insurance costs.

[mr_warbird]

As a suggestion, if a reader is a mechanical engineer and has a fluid dynamics simulation package, it would be very interesting to run a simulation of the horizontal under the same conditions this accident occurred. It would be necessary to model very accurately the trim tab position, amount of elevator deflection, air density, temperatures, air velocity.... and such and see what types of forces are at play or what types of elevator deflection is necessary to create a momentary supersonic airflow over the trim tab, (on the under surface when the elevator is deflected upward as was the case when the plane was pulling +Gs around the pylon when the tab failed)

[CoastieJohn]

I believe in the late 90s there was another P-51 (could have been Voodoo) that also had the trim tab ripped off at Reno in a race. After that tore off, the aircraft went straight up for a 1000 feet, the massive G forces caused the pilot to black out. Fortunately the pilot regained his senses after a few moments and was able to land the plane without an accident.

I am quite certain we are seeing a similar failure here with Galloping Ghost. I believe the pilot probably blacked out right after the tab cam off when the aircraft bolted skyward pulling significant G forces, and may or may not have regained senses before the crash.

I do have a theory as to why we are seeing several P-51s losing trim tabs - momentary supersonic airflows over the tail surface. At 500 or so MPH, if a pilot makes an abrupt elevator movement, it is potentially possible to get a local increase in airflow over control surface which could exceed the speed of sound - this will cause shock waves and stresses for which the trim tab component (as well as the whole aircraft) were not designed to withstand.

If this turns out to indeed be the case, it will be interesting to see how the FAA responds. Basically, it could be the unlimited racers are operating so close to the sound barrier with the latest technology and modifications to P-51s that they are encountering momentary airflows and shock waves that the airframes were just simply not designed to support.

I really hope the Reno air races continue (this must be a difficult challenge for the organizers), it will be a very sad blow to the warbird, racing and aviation community as a whole if it is no longer allowed or too expensive as a result of increased insurance costs.

That is an interesting theory. What do you think about parasitic drag being so great that at the high speeds any fluctuation out of horizontal stab's chordline compounds the effect and would pull the tab off?

[sdennison]

No fire? Thoughts?

[k5083]

No fire? Thoughts?

For me that aspect vividly brought to mind an old Air Classics article that I read covering a fatal Bearcat crash at Reno, or maybe it was Mojave, in the 70s. There was a fiery explosion out on the course and the article writer recorded some comments from people on the field, including one who said, "Can't be a Mustang. Mustangs don't burn." Maybe someone else recalls details of the article.

August

[WIXMOD-Alpha]

Let's be really cautious about speculation folks... A lot of stuff like the trim tab is already out there in the media and is probably fair game for discussion, but we wouldn't want to be the source of misguided rumors.

[jtramo]

With the speed of sound being closer to the mid 700mph range at that density alt I dont see how elevator movement could have accelerated the tail past the speed of sound. I have never heard of elevator movement accelerating the wave, just the wave influencing elevator movement and then of course basic MCRIT. Anywhere I can read up on this?

However mcrit is defined as "the point at which *any* part of the wing reaches mach 1. I doubt they are anywhere near that BUT the mcrit number isny always the same and can begin near .72mach or less.....540mph if mach is 750mph.

[Taigh Ramey]

I beleive that the lack of fire was related to the explosion supressant foam that was in the fuel tanks. The foam remnants are all over the ramp and have been drifting down wind from the crash site. Here is a photo of the foam on the NAHI ramp:



Things could have been much much worse.

[Paul Krumrei]

Let's be really cautious about speculation folks... A lot of stuff like the trim tab is already out there in the media and is probably fair game for discussion, but we wouldn't want to be the source of misguided rumors.

No one is pointing blame on anyone. Knowing some of the facts, we are discussing the possibilities.

Is this not what a discussion board is for to discuss things like this.

Unless it gets to the point where people are point blank saying "this is the reason" I suggest that we continue investigating based on the already obvious evidence that has been pointed out.

Otherwise, what is the sense of having a discussion board?

I don't want to sound like an ungrateful prick, and maybe I am just waking up and not had my caffeine but I think you need to "moderate" it only when it is driven to the point brought to what I mentioned above.

[Steve Nelson]

Latest reports are that another one of the injured has passed away, raising the number of fatalities to ten. Six still critical. Thoughts and prayers to all the victims and their families.

I'd like to thank all those who've contributed to this thread for sharing their expertise. It's very informative to us non-pilot types.

SN