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  #71  
Old 08-19-2022, 03:57 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
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Default Test Pilot Mode

If you built an EAB and flew the entire phase one, certifying documentation as required-exactly what mode were you in if not test pilot mode?
To the letter of FAA requirements for EAB the airplane must be tested at least to Vne and some would argue to 110% of Vne.
The Atlantic city accident has strong evidence of gross overspeed, far in excess of Vne. In some of the other accidents such evidence is not very strong. In the Utah accident the NTSB was uncertain which of two ground tracks was the accident airplane. The Washington accident was a vertical event according to witnesses. Most of the airplane was not recovered from the water.
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  #72  
Old 08-19-2022, 07:31 PM
swift12 swift12 is offline
 
Join Date: May 2021
Location: Palmerston North
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Default

if you want to get all scientific about mass balancing and flutter.
https://raptor-scientific.com/conten...l_Surfaces.pdf
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  #73  
Old 08-19-2022, 07:51 PM
swift12 swift12 is offline
 
Join Date: May 2021
Location: Palmerston North
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And from the New Zealand accident report...

"Anecdotal evidence from individuals who knew the pilot, indicated that the pilot liked to fly “around the clouds”. On the day before the accident flight, the pilot had conducted a local flight in ZK-DVS, to the north-west of Whangarei. During this flight, the pilot climbed the aircraft to an altitude of approximately 6,000ft. On the accident flight the pilot climbed the aircraft to an altitude of approximately 4,500ft. On both days cloud layers were reported to be either at or below these altitudes (refer environmental factors section).
In addition to holding a private pilot licence - Aeroplane (PPL-A), the pilot also held an airline transport pilot licence - Helicopter (ATPL - H), with an instrument rating. Thus, the pilot would have received training and operational experience in IMC during his piloting career.
Although the pilot held an instrument rating, research has shown that the effects of spatial disorientation associated with an inadvertent IMC encounter, can still impact the performance of instrument rated pilots.3
The safety investigation could not conclusively determine if the aircraft inadvertently entered cloud. If, however, an inadvertent IMC encounter did occur, it is possible the pilot experienced the effects of spatial disorientation, leading to the aircraft entering an unusual attitude."

Bearing in mind these are slippery aircraft unlike some aircraft that are very draggy. Get these noses down too long and quickly find yourself in trouble. Respecting VNE, VA, training and flying within your ability level are the keys here. There have been many safe hours flown in RV's worldwide. If you are a low time private pilot consider advanced training of how to get out of something if you get into it and more importantly how not to get into it in the first place.
I, like many here fly commercially and have over 20000 hours but I'm going to get trained on my RV 7 when its built by an experienced RV pilot and approach it with the same professionalism I do in my day job. One ex colleague does flight testing for BFR's now and its surprising to hear some don't even know how to do a weight and balance on their aircraft.

I went to take a C172 for a weekend and needed to get current....maybe 10 or 15 years since i flew the last lighty. The young instructor said to me I wont do to much as you are very experienced....I said yes I am....on airliners....not 172's so you do what you need to ensure I'm safe. the first landing I think I rounded at 50 feet and couldn't find the ground....lol. My point is...even for fun you have to approach flying seriously to be safe and these accidents point to not design faults but pilot error.
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Last edited by swift12 : 08-20-2022 at 12:22 AM.
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  #74  
Old 08-19-2022, 11:53 PM
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DanH DanH is offline
 
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Default

Quote:
Originally Posted by BillL View Post
This is speculation and should be removed.
I think the rules allow us to speculate at will, after the full reports are published.
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  #75  
Old 08-20-2022, 12:20 AM
swift12 swift12 is offline
 
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Quote:
Originally Posted by DanH View Post
I think the rules allow us to speculate at will, after the full reports are published.
this is absolutely from the official accident report and not something I made up. the rest is my opinion. cheers DanH.
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  #76  
Old 08-20-2022, 12:27 AM
swift12 swift12 is offline
 
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Quote:
Originally Posted by BillL View Post
This is speculation and should be removed.
Thanks Bill I edited my opinion on what caused this accident however reiterate this information comes from the official report. whatever happened he got to 244 knots and if you read the report these snapshots are taken 5 seconds apart so the speed may have even been higher than that.

also from the report...."The safety investigation could not conclusively determine if the aircraft inadvertently entered cloud. If, however, an inadvertent IMC encounter did occur, it is possible the pilot experienced the effects of spatial disorientation, leading to the aircraft entering an unusual attitude". so that is speculation only on my part...rightly or wrongly....simply my opinion...I had a student once put me in a 90 degree angle of bank over a VOR in an Arrow.....its always a possibility.

also the report detailed his experience on the sikorsky heli he operated and the recovery from an unusual attitude is different than for a fixed wing...namely reducing the power in a fixed wing versus increasing power in a heli....and possibly resulting in a time delay reducing power with increasing airspeed in a high angle of bank nose low situation.

Whatever happened the point is looking at the data and the report rudder flutter was the cause from overspeeding the aircraft. They even show other breakup rudders and they all seem to show the same damage...broken in the middle and unzipped....all caused by flutter. (and high speed events)

hey Im just keen on learning everything possible....because i dont want it to happen to me.
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Last edited by swift12 : 08-20-2022 at 12:38 AM.
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  #77  
Old 08-20-2022, 11:37 AM
theduff theduff is offline
 
Join Date: Jan 2012
Location: L-18
Posts: 398
Default RV-4 wing separation

Quote:
Originally Posted by Roadjunkie1 View Post
There was a post a while ago, possibly referring to a Kitplanes article, about the most common cause of RV-4 wings parting company with the airplane. As I remember, it was pilots newly acquiring an RV-4, not builders, that would execute a fast low pass with a zooming pull-up. Easy to overstress any airplane. The RV series is very responsive without being twitchy but even SMALL stick inputs can results in LARGE changes in attitude. Pull the stick back half an inch at cruise and see how fast you are suddenly at another altitude. .
Too my knowledge there has never been a in flight wing separation in an RV-4. If you have an actual incident I would be very interested in hearing about it.

Duff
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  #78  
Old 08-20-2022, 12:19 PM
jrs14855 jrs14855 is offline
 
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Location: Lake Havasu City AZ
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Default Wing Separation

In some of the RV7 reports the breakup starts with the failure of the vertical tail, followed by the horizontal tail, then the wing(s) The NZ report clearly states rudder flutter.
So yes, the wings failed, probably a result of G forces far beyond the design strength. Probably a G load similar to what Van discusses in "Aerobatic Epistle".
Once again-the Washington accident-most of the airplane was never recovered so no sequence of events in the NTSB final.
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  #79  
Old 08-20-2022, 12:35 PM
jrs14855 jrs14855 is offline
 
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Default RV4

A search using RV-4 wings folded will confirm that at that time there had never been a structural failure of an RV-4. I believe that remains correct.
That misconception likely came from confusing an early RV8 wing failure with the RV4.
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  #80  
Old 08-20-2022, 03:38 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
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Default Limitations

Flying within published limits is a very admirable goal.
When I was instructing aerobatics full time in the Pitts S2B, T34, Stearman and Sukhoi SU29 I would always try to provide time for a short chat with a new trainee beyond the standard briefing.
An older gentleman showed up. What do you fly? RV6. Do you have any aerobatic experience? "Well I was trying to do rolls in the RV and I got confused and stopped the roll inverted and pulled. How fast did you get. Almost 300 but the worst part was I almost hit the ground.
I do not recall a discussion of G load. The point is the pilot and the airplane survived. All indications are that he would have survived in a RV4. But likely not in a RV7.
I have some very strong opinions on how this should be remedied but I will bite my tongue for now.
I am motivated by a number of reasons. Very high on the list is that I exchanged a series of emails with the pilot who died in the Atlantic City area crash. I wonder if I missed an opportunity to try and talk him out of "teaching himself rolls".
I detest seeing the words aerobatics, homebuilt and structural failure and fatal all in the same paragraph.
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