VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #21  
Old 10-02-2015, 03:09 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,104
Default Roll Bar

There is a lot of precedent for the roll bar in front of the pilot. T18 Midget Mustang etc.
If you look at any type of race car as well as some sports cars that are not raced, the roll bar is ALWAYS behind the drivers head. That is the location that provides the optimum protection for the pilots and passengers heads.
Forget about after the flip. One needs to survive the flip with the skull intact or you will not be getting out anyway.
Protection from the vertical fin is also a fallacy. What if the vertical tail is buried half its height in mud??
A much heavier airplane but Charlie Hilliards fatal accident at Sun n Fun 1995 makes an excellent case to study. Roll bar removed, flipped in soft ground, fin did not provide much protection.
Reply With Quote
  #22  
Old 10-02-2015, 03:30 PM
jrs14855 jrs14855 is offline
 
Join Date: Apr 2008
Location: Lake Havasu City AZ
Posts: 2,104
Default Water

There is a fairly recent video of an airshow pilot in a 450 Stearman hitting the water quite hard at the bottom of a looping maneuver. IIRC the airplane flipped and he got out on his own, essentially uninjured.
Reply With Quote
  #23  
Old 10-02-2015, 08:46 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 7,646
Default

After this long I am still surprised how every time one of these discussions develops here on VAF, there are recommendations that jettisoning the canopy before a forced landing is a good option.

Everyone is entitled to an opinion, and everyone has to develop their own plan, so this is not meant to flame anyone, but I hope it will induce some very serious thinking (and possibly some thoughtful conversation) before anyone would settle on this as a good option (whether it be a forced landing in water or on land).

Even though we tend to get the idea that the canopy is very fragile (because of occasional cracks near drilled holes, etc.) acrylic is actually quite strong. Try and purposely break some sometime if you have the chance. I have done tests. It is not easy.

When RV's flip and the top of the canopy gets broken, that implies that a lot of impact load was absorbed by the canopy. Would you really rather have nothing between your head/face and what ever surface the canopy would have come into contact with (if it was still there)?

What about water? Anyone participate in high speed water sports (water skiing, etc.). Water at only 40 MPH feels very hard... and that is when moving somewhat parallel to its surface. Imagine what it might feel like if you where to be rapidly slammed into it nearly perpendicular to the surface.
I choose to have a canopy between my head and that hard water surface.

Back to forced landing on land.... what if the ground is soft... you got rid of your sliding canopy... the flip is violent enough that you still have fwd (now backwards) movement once inverted... the windscreen / roll bar assy. now acts as big scoop in the soft ground which induces enough fwd load to fail the roll bar by folding it fwd.... you may have now lost any escape benefit you hoped to have.

Going into trees... it is fairly common for airplanes to roll, yaw, tumble as they come down through trees... my preference is to have something between me and all of the tree limbs trying to poke inside.

I could go on and on..... maybe others have ideas as well.

Bottom line, when making a plan, think through the entire accident scenario. Not just a single aspect that you think might be the most critical point... a wrong decision could easily shift it from one thing to another
__________________
Any opinions expressed in this message are my own and not necessarily those of my employer.

Scott McDaniels
Hubbard, Oregon
RV-6A (aka "Junkyard Special ")
Reply With Quote
  #24  
Old 10-02-2015, 10:16 PM
F1R F1R is offline
 
Join Date: Nov 2010
Location: ____
Posts: 581
Default Off airport is not the problem

Quote:
Originally Posted by curtis View Post
Most all of the reports I have ever read ALL RVs (tailwheel or nose wheel) that land off airport will end up on their back.
Vlad would respectfully disagree with you. Likely a few hundred off airport landings in his 9A and it's still a very useable 9A.

RV's and other trike and TW AC can be landed off airport, however, any landing surface that is too soft will very often result in a flip over.

The small 5.00 x5" main wheels require a firm enough surface to roll. A dry pasture, a dirt or gravel road would provide a firm enough surface for a landing roll.

Vlad has even been known to use wet sand to land on and take off from.

On the flip side my neighbour landed his cub in my field one night, and almost flipped. The field was just seeded and very soft, even 6.00 tires sunk in and produced more drag than he was expecting.

Last edited by F1R : 10-02-2015 at 10:49 PM.
Reply With Quote
  #25  
Old 10-02-2015, 10:38 PM
F1R F1R is offline
 
Join Date: Nov 2010
Location: ____
Posts: 581
Default AIR BAG on Top

A large enough air bag mounted on the top of the firewall and or on top of the vertical stab. that fired when the top of the V STAB impacted might provide better impact protection and/or better egress after the event. You sure would not want any deployment in flight. Perhaps a manual fired air bag or bags might be a better option.
Possibly a nose gear failure could fire the bags on top.

Last edited by F1R : 10-02-2015 at 10:47 PM.
Reply With Quote
  #26  
Old 10-03-2015, 04:26 AM
curtis's Avatar
curtis curtis is offline
 
Join Date: Jan 2005
Location: Kansas
Posts: 384
Default

Quote:
Originally Posted by F1R View Post
Vlad would respectfully disagree with you. Likely a few hundred off airport landings in his 9A and it's still a very useable 9A.

RV's and other trike and TW AC can be landed off airport, however, any landing surface that is too soft will very often result in a flip over.

The small 5.00 x5" main wheels require a firm enough surface to roll. A dry pasture, a dirt or gravel road would provide a firm enough surface for a landing roll.

Vlad has even been known to use wet sand to land on and take off from.

On the flip side my neighbour landed his cub in my field one night, and almost flipped. The field was just seeded and very soft, even 6.00 tires sunk in and produced more drag than he was expecting.
I'm curious what you define as an off airport landing? To me, an off airport landing is putting your aircraft down somewhere no one has ever landed or even done a preliminary check with a vehicle, such as in an emergency. Grass strips, abandoned airports, and any other surface where numerous other people have already landed and proven the surface safe to do so does not fall into the category of what is being discussed here in my opinion.
__________________
RV-6A Slider
550 hours +

Build it light and cheap

Last edited by curtis : 10-03-2015 at 04:32 AM.
Reply With Quote
  #27  
Old 10-03-2015, 04:53 AM
plehrke's Avatar
plehrke plehrke is offline
 
Join Date: Sep 2006
Location: Defiance, MO
Posts: 1,404
Default

Quote:
Originally Posted by rvbuilder2002 View Post
After this long I am still surprised how every time one of these discussions develops here on VAF, there are recommendations that jettisoning the canopy before a forced landing is a good option.

Everyone is entitled to an opinion, and everyone has to develop their own plan, so this is not meant to flame anyone, but I hope it will induce some very serious thinking (and possibly some thoughtful conversation) before anyone would settle on this as a good option (whether it be a forced landing in water or on land).

Even though we tend to get the idea that the canopy is very fragile (because of occasional cracks near drilled holes, etc.) acrylic is actually quite strong. Try and purposely break some sometime if you have the chance. I have done tests. It is not easy.

When RV's flip and the top of the canopy gets broken, that implies that a lot of impact load was absorbed by the canopy. Would you really rather have nothing between your head/face and what ever surface the canopy would have come into contact with (if it was still there)?

What about water? Anyone participate in high speed water sports (water skiing, etc.). Water at only 40 MPH feels very hard... and that is when moving somewhat parallel to its surface. Imagine what it might feel like if you where to be rapidly slammed into it nearly perpendicular to the surface.
I choose to have a canopy between my head and that hard water surface.

Back to forced landing on land.... what if the ground is soft... you got rid of your sliding canopy... the flip is violent enough that you still have fwd (now backwards) movement once inverted... the windscreen / roll bar assy. now acts as big scoop in the soft ground which induces enough fwd load to fail the roll bar by folding it fwd.... you may have now lost any escape benefit you hoped to have.

Going into trees... it is fairly common for airplanes to roll, yaw, tumble as they come down through trees... my preference is to have something between me and all of the tree limbs trying to poke inside.

I could go on and on..... maybe others have ideas as well.

Bottom line, when making a plan, think through the entire accident scenario. Not just a single aspect that you think might be the most critical point... a wrong decision could easily shift it from one thing to another
Excellent advise for emergency preparedness. Think of all the scenarios and work through possible outcomes.
Just want to add additional food for thought. Where will the canopy go in the process of separating from the airplane? Most likely hit the vertical tail or even could whack you in the head.
__________________
Philip
RV-6A - 11 years over 800 hours
Cessna 140 - 68 years over 3400 hours
Based at 1H0 (Creve Coeur)
Paid dues yearly since 2007
Reply With Quote
  #28  
Old 10-03-2015, 08:16 PM
pilot28906 pilot28906 is offline
 
Join Date: Apr 2006
Location: Murphy, NC
Posts: 399
Default

Thanks for all the info and insights. It does seem that ending up on your back with an off field landing is very probable. There may not be a "best" option with the canopy as both seem to provide good protection.

Thanks again.
__________________
John Johnson
Murphy, NC
RV7
Reply With Quote
  #29  
Old 10-04-2015, 07:34 AM
Bill Boyd's Avatar
Bill Boyd Bill Boyd is offline
 
Join Date: Sep 2006
Location: Landing field "12VA"
Posts: 1,095
Default

Quote:
Originally Posted by rvbuilder2002 View Post
After this long I am still surprised how every time one of these discussions develops here on VAF, there are recommendations that jettisoning the canopy before a forced landing is a good option.

Everyone is entitled to an opinion, and everyone has to develop their own plan, so this is not meant to flame anyone, but I hope it will induce some very serious thinking (and possibly some thoughtful conversation) before anyone would settle on this as a good option (whether it be a forced landing in water or on land).

Even though we tend to get the idea that the canopy is very fragile (because of occasional cracks near drilled holes, etc.) acrylic is actually quite strong. Try and purposely break some sometime if you have the chance. I have done tests. It is not easy.

When RV's flip and the top of the canopy gets broken, that implies that a lot of impact load was absorbed by the canopy. Would you really rather have nothing between your head/face and what ever surface the canopy would have come into contact with (if it was still there)?

What about water? Anyone participate in high speed water sports (water skiing, etc.). Water at only 40 MPH feels very hard... and that is when moving somewhat parallel to its surface. Imagine what it might feel like if you where to be rapidly slammed into it nearly perpendicular to the surface.
I choose to have a canopy between my head and that hard water surface.


Back to forced landing on land.... what if the ground is soft... you got rid of your sliding canopy... the flip is violent enough that you still have fwd (now backwards) movement once inverted... the windscreen / roll bar assy. now acts as big scoop in the soft ground which induces enough fwd load to fail the roll bar by folding it fwd.... you may have now lost any escape benefit you hoped to have.

Going into trees... it is fairly common for airplanes to roll, yaw, tumble as they come down through trees... my preference is to have something between me and all of the tree limbs trying to poke inside.

I could go on and on..... maybe others have ideas as well.

Bottom line, when making a plan, think through the entire accident scenario. Not just a single aspect that you think might be the most critical point... a wrong decision could easily shift it from one thing to another
All true observations; no water skier would disagree about what it feels like. But when I consider an over-water crossing like the Pamlico Sound that lies between me and the Outer Banks, I factor in the likelihood of ending up on my back in water with an average depth of seven feet for miles in any direction, and make the crossing at an altitude that allows gliding to shore. My canopy jettison handle was removed from the panel when I realized there was no way a tip-up 6 canopy would be jettison-able in flight without further mods to the forward deck (slots) and I didn't want rain leaks. Having to live with that choice means I will never be comfortable with a water ditching scenario and subsequent drowning.

Maybe someone will develop a drogue/sea anchor that could be released at the moment of impact in a water ditching. Not that it would ever be worth the weight or risk of inadvertent deployment, but it might mitigate the nose-over.

To make water ditchings survivable in RV's (except 10's, I suppose - doors are different) we must
make the nose-over event unlikely;
add floatation such that for at least a minute the canopy can be opened in shallow water while inverted (wings full of ping-pong balls?);
be able to jettison canopy before impact;
or provide rescue air for all occupants several minutes' worth of hatchet/breaker tool work upside down in flooded cockpit with dim to no visibility.

Last edited by Bill Boyd : 10-04-2015 at 07:42 AM.
Reply With Quote
  #30  
Old 10-15-2015, 10:13 PM
Blain's Avatar
Blain Blain is offline
 
Join Date: Mar 2013
Location: El Dorado Hills, CA
Posts: 645
Default How about a slider with Sikaflex?

It has been brought up that breaking out a canopy set in Sika could be much more difficult. Anyone with this experience?
__________________
Blain
R-22 sold.
RV-8 AW Cert 02-09-17
N82 Sierra Tango
Avatar courtesy of AircraftStickers.com!
Dues gladly paid thru Nov. 2018(my reminder)
.
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 02:12 AM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.