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  #181  
Old 06-10-2020, 11:51 AM
gerrychuck gerrychuck is offline
 
Join Date: Jun 2011
Location: Moose Jaw, SK, Canada
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Quote:
Originally Posted by emsvitil View Post
There is a mechanism for "whiplash" and this accident points right at it...

A forward flip, then sudden stop would be the same as being rear-ended.
Exact opposite; the initial deceleration is forward, equivalent to a front-end collision, as the nose gear digs in.
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Gerry Julian
Moose Jaw Saskatchewan
RV6A "Second Wind" C-GERZ (born N242UL)
O-360 A1A, Sensenich FP prop

Those who think any system is foolproof greatly underestimate the ingenuity of fools
  #182  
Old 06-11-2020, 07:35 AM
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Snowflake Snowflake is offline
 
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Quote:
Originally Posted by gerrychuck View Post
Exact opposite; the initial deceleration is forward, equivalent to a front-end collision, as the nose gear digs in.
This is my thought as well. Once you're going upside down, the majority of your motion is vertical, towards the ground. Very little "forward" (or tail pointing forward) motion remains after the engine has dug in, to give you any whiplash back into your seat.
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Rob Prior
1996 RV-6 "Tweety" C-FRBP (formerly N196RV)
  #183  
Old 06-11-2020, 11:40 AM
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Caveman Caveman is offline
 
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Location: Oklahoma
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Originally Posted by Snowflake View Post
What would provide the force to "recoil" someone into the seat? There are no springs or recoil mechanisms in most light aircraft. More likely would be the seat hitting you in the back as the rest of the airplane comes to a stop after you do.
For sake of the conversation, no two accidents are alike and the shoulder harness seat belt system stretches much more that most realize and then may pull you back. I remember years ago that Wayne Handley crashed the turbo Raven and video was dramatic in illustrating this point. The only one I can find now is low resolution but is still a good example of some of the various dynamics affecting a body during a crash. If you watch this in slow motion you can see Wayne nearly get ejected from the airplane and pulled back in. The second impact is the most violent. The aircraft also turns and slides backwards before coming to a stop.

https://www.youtube.com/watch?v=BJWjbpA_zIc
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Joe Schneider
RV-7, IO-360, BA Hartzell, N847CR
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  #184  
Old 06-11-2020, 12:44 PM
gerrychuck gerrychuck is offline
 
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Location: Moose Jaw, SK, Canada
Posts: 550
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Wow; that is a lot of vertical g-force. I would be shocked if he didn't suffer compression fractures with that impact. He is fortunate to be alive for sure. As a side note, I shared my hangar for 5 years with a former Snowbird pilot who now flies a Pitts as a civilian airshow performer (Brent Handy). He did all his Pitts training with Wayne about 6 years ago.
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Gerry Julian
Moose Jaw Saskatchewan
RV6A "Second Wind" C-GERZ (born N242UL)
O-360 A1A, Sensenich FP prop

Those who think any system is foolproof greatly underestimate the ingenuity of fools
  #185  
Old 06-11-2020, 07:12 PM
Robert Sailor Robert Sailor is offline
 
Join Date: Nov 2018
Location: Nanaimo BC Canada
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Quote:
Originally Posted by gerrychuck View Post
Wow; that is a lot of vertical g-force. I would be shocked if he didn't suffer compression fractures with that impact. He is fortunate to be alive for sure. As a side note, I shared my hangar for 5 years with a former Snowbird pilot who now flies a Pitts as a civilian airshow performer (Brent Handy). He did all his Pitts training with Wayne about 6 years ago.
Brent is currently enroute from Mexico to the USA east coast on their sailboat. Nice fellow, nice family...looking forward to some flying.
  #186  
Old 06-11-2020, 10:52 PM
JDeanda JDeanda is offline
 
Join Date: Apr 2013
Location: Ventura, CA
Posts: 151
Default Wayne's Tale

Wayne did indeed have some serious spinal compression injuries, to the point he figured he'd never fly again. But he did, and even did some airshows. Great guy.
  #187  
Old 06-12-2020, 07:15 AM
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Snowflake Snowflake is offline
 
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Quote:
Originally Posted by Caveman View Post
For sake of the conversation, no two accidents are alike and the shoulder harness seat belt system stretches much more that most realize and then may pull you back.
No. Neither nylon webbing nor the common cables used to attach it to the airframe (where it's not bolted directly) have any significant "springiness" to provide recoil. They're designed specifically to absorb the impact by stretching *without* recoil, as snapping back like a rubber band could cause further injury in an accident.

Quote:
If you watch this in slow motion you can see Wayne nearly get ejected from the airplane and pulled back in. The second impact is the most violent. The aircraft also turns and slides backwards before coming to a stop.
You must be seeing something i'm not. He is almost ejected, yes, but only to the limits of his restraint's travel, before gravity pulls him back in... That's not "recoil." And while the plane is turning and sliding to a stop backwards, you don't see his head moving aft.
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1996 RV-6 "Tweety" C-FRBP (formerly N196RV)

Last edited by Snowflake : 06-12-2020 at 07:20 AM.
  #188  
Old 06-14-2020, 08:31 AM
Captain Avgas Captain Avgas is offline
 
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Location: Melbourne, Australia
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Quote:
Originally Posted by simpkinsona View Post
There?s no reason for a nose gear failure on takeoff other than poor pilot techniques.

-Andy
On the contrary, I would say there?s no reason for a nose gear failure on takeoff other than poor nose gear design.

I fully understand that good takeoff procedure in an RV(A) is to lift the nose gear off the ground during the takeoff run as soon as there is elevator authority available to do so...and I am not advocating any other technique. However for those who insist in barrelling down the runway and pulling the nose gear off the ground at rotation the price should not be a nose gear collapse which is what happened at the Avalon Airshow. Any valid nose gear design should have enough structural redundancy to put up with this type of poor take off technique. After all, this is the type of take off technique employed by 90% of private pilots.

Just go to any busy general aviation airfield and watch the light aircraft take off....virtually no one lifts the nose gear off the ground earlier than rotation. Terrible technique admittedly, but any reasonably designed nose gear should be able to comfortably put up with that punishment. If it can?t then that simply means the safety margin is way too slender.
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RV7A
  #189  
Old 06-14-2020, 12:50 PM
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rvbuilder2002 rvbuilder2002 is offline
 
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Location: Hubbard Oregon
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Quote:
Originally Posted by Captain Avgas View Post
the price should not be a nose gear collapse which is what happened at the Avalon Airshow.
If this occurred on a properly maintained / paved runway, then I would contend that there are other extenuating circumstances that haven't been provided, that could possibly provide an explanation.

It is unreasonable to lump every single failed nose gear accident that has occurred on RV's into the same group and state that if only the nose gear was designed as it should have been, that none of those accidents would have occurred.
It is basically saying that anything designed correctly should not be able to be broken by any user. Taking that position is just plain wrong.

You have not provide any info other than an accident ended with a failed nose gear that occurred during take-off in an A model RV. That in itself does not mean that the fault is with the design of the airplane.

Now if this accident occurred on a dirt / grass runway, the fact that a large percentage of pilots use poor technique for every take-off is also not a reason to cast blame on the airplane.



I have a serious question.

If an airplane should be able to survive any level of technique (in some instances maybe "abuse" would be more appropriate), why do you suppose there is so much emphases on training pilots to use soft field take-off and landing techniques (at least it is a standard here in the U.S., so I assume elsewhere as well)

The answer is - Because the nose gear on a tricycle geared airplane takes the most abuse and is probably the most vulnerable component on the airplane to damage by the typical user.

If the contentions that are often made were true (most pilots fly the same... nose gear stuck to the runway, properly designed airplanes can always tolerate what ever techniques the average pilot uses, etc.), then why would the people that have been in charge of developing and evolving the training curriculum's have every added soft field take-off and landing techniques to the syllabus?

And by the way, the proper definition of a soft field runway surface is not a muddy farm meadow out behind the barn where your airplane will be covered with mud after landing or taking off.

It is any surface that is not hard (meaning concrete or asphalt).

Why?

Because the surface condition of any soft field runway has a high chance of having issues today, that weren't there yesterday.

One thing we can agree on is that a large percentage of the pilot community has obviously forgotten at least some of the basic fundamentals they were taught while training to be a pilot.

Hopefully discussions like these will cause us all to do some self evaluation on a regular basis and look to improve in areas that we might be deficient.

A personal tool I use is to ask my self...
Is there anything (piloting skill, knowledge, etc.) that I can think of that if I needed to perform it for an examiner on the next flight I make as pilot(meaning not going out and doing some advanced practicing or study prep.), that I couldn't do it to well beyond the minimum standard I had to meet when I because a pilot.

When we pass an examination for any rating we have shown that we at least meet the minimum requirements.

Anyone that has been flying for quite a while should be able to easily exceed all of those minimums.
If there is something that they think they probably couldn't, that would be a very good thing to personally challenge yourself with improving on.

Remember... many of the skills we are taught are things that are not going to be used on a regular basis.
Soft field take-offs and landings are a good example.... emergency forced landings are another.
Often times when we need to utilize those skills, we aren't provided the opportunity to practice for a while before we execute them.
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Van's Aircraft Engineering Prototype Shop Manager
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
  #190  
Old 06-14-2020, 03:08 PM
SPX SPX is online now
 
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Location: San Diego
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When this topic comes up, I often think about the RV-6A that Mike Seager operates out of Vernonia. That airplane has thousands of hours, and likely tens of thousands of landings. It does not have any third-party nose gear modifications, operates out of the grass runway at Vernonia for at least two takeoff and landings everyday, and is used exclusively for training.. aka: it sees a lot of less than perfect technique.

The nose gear on this aircraft hasn't collapsed. Why? Could it be that Mike does not allow the airplane to continue the approach when it's too fast, too high, about to touch nose first, or three pointed? Instead, opting for go around and trying again? If so, does this perhaps imply that perfect technique is not required, but rather just something better than an abusive technique?

Van's has alluded to the fact that design choices were made with the nose gear that perhaps make it less robust than something that is over engineered and more tolerant of abuse. (See this short piece) But, just because the nose gear is less tolerant of abuse, that does not mean that it's poorly designed.

Scott -- Do you have any info on the number of hours and/or landings on the RV-6A that Mike has Vernonia?
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