Safety and Warbird Acro
Wed Nov 04, 2009 12:40 pm
70 % OF WARBIRD FATAL ACCIDENTS ARE FROM LOW ALTITUDE ACRO !
Hopefully that got your attention, especially anyone who is new to warbirds.
Let me explain and clarify that a little. First, this is only my guesstimate, I have not seen exact figures. But I am pretty sure this is in the ballpark. Next when I say acro, or aerobatics, I am referring also to hard high g like maneuvers that might not actually be aerobatic. If you come down the runway at 50 feet in a T-6 with a heavy passenger in the back seat and roll into a 60 % bank and pull hard; it may result in an accident just as if it was fully aerobatic. The strict definition of aerobatic would be a bank of more than 60* and/or pitch up or down of more than 30*. A 30* change in pitch from level flight is fairly steep, a normal climb out is about 5 or 10 *. A 60* bank is part of the commercial pilot test so is still considered normal. In airshows the FAA may use 70* or so as the definition, no one has a protracter anyway.
Why am I bothering to make such a big deal about this? Read the first sentence again.
Just recently there was a discussion on WIX about warbird acro, interesting and informative, all well and good. But there was not much mention of the history of accidents from this.
Yes,I know the party line, the mantra is that we are highly skilled and trained professionals , ace of aces , the envy of mere mortals, and we'd never make a mistake. It must be only the novices who are caught in this realm. Could never be anyone like Art Scholl could it? And of course we are so much better than he was. We can eat the onion burrito for breakfast and never even need a breath mint.
The point I am trying to make is two fold. Yes, training and skill are prime in learning to fly warbirds and especially acro. But they are no guarantee, it does not make you immortal. I don't care how good you are, there is increased risk the lower you do acro and the farther you vary from normal flight. I wouldn't ride through a loop at 50 feet even it was with Patti Wagstaff or Bob Hoover, unless it was necessary for training. And certainly would not do that with a passenger on board.
The potential danger goes up as you get lower. If you do your snap rolls on takeoff in a T-6 (Harvard) you have few feet for margin of error. You'd better be as good as Bud Granley. Or doing a roll at perhaps 100 feet after takeoff like Elliot Cross did in the Spitfire at Oskosh, you have to be good, there is just so little room for error. I am not as good as these folks, I leave more room. I have had a low altitude acro permit since I got it from the FAA in a CAF show in 1987. My limit is 500 feet, I don't need do do it any lower. There is a little wiggle room there, if I were to loose a few feet coming out of a roll a little nose low. There is just no margin at 50 feet. I don't practice hours daily all week long like the top folks do.
Another factor is what type act you do. The farther you get from normal flight the more it takes to recover. A simple roll is not that big a departure from a steep turn, just more so. You need to keep the nose above or around the horizon and start with the correct entry speed and most of all not pull Gs when inverted. But the normal progression, given room will bring you back to level flight. Looping maneuvers are more "abnormal", anything vertical involves the potential for a stall at the top or over g or a dive into the ground at the bottom. If it involves an intentional stall/spin, then you have in effect moved from "flying " to "falling" , and have to do a little more to get back to normal flight. This "little more" may take more skill and if anything goes wrong, make need more time/altitude to recover.
This has gotten longer than I intended and I haven't covered types of planes yet.
The point I am trying to make is be very careful, If you do this stuff down low it is not good enough to be right most of the time. It's not like being a winning pitcher in baseball with a 20-10 record.
And don't do it at all with a passenger unless you have lot's of air under your and that means thousands of feet, not hundreds.
Hopefully that got your attention, especially anyone who is new to warbirds.
Let me explain and clarify that a little. First, this is only my guesstimate, I have not seen exact figures. But I am pretty sure this is in the ballpark. Next when I say acro, or aerobatics, I am referring also to hard high g like maneuvers that might not actually be aerobatic. If you come down the runway at 50 feet in a T-6 with a heavy passenger in the back seat and roll into a 60 % bank and pull hard; it may result in an accident just as if it was fully aerobatic. The strict definition of aerobatic would be a bank of more than 60* and/or pitch up or down of more than 30*. A 30* change in pitch from level flight is fairly steep, a normal climb out is about 5 or 10 *. A 60* bank is part of the commercial pilot test so is still considered normal. In airshows the FAA may use 70* or so as the definition, no one has a protracter anyway.
Why am I bothering to make such a big deal about this? Read the first sentence again.
Just recently there was a discussion on WIX about warbird acro, interesting and informative, all well and good. But there was not much mention of the history of accidents from this.
Yes,I know the party line, the mantra is that we are highly skilled and trained professionals , ace of aces , the envy of mere mortals, and we'd never make a mistake. It must be only the novices who are caught in this realm. Could never be anyone like Art Scholl could it? And of course we are so much better than he was. We can eat the onion burrito for breakfast and never even need a breath mint.
The point I am trying to make is two fold. Yes, training and skill are prime in learning to fly warbirds and especially acro. But they are no guarantee, it does not make you immortal. I don't care how good you are, there is increased risk the lower you do acro and the farther you vary from normal flight. I wouldn't ride through a loop at 50 feet even it was with Patti Wagstaff or Bob Hoover, unless it was necessary for training. And certainly would not do that with a passenger on board.
The potential danger goes up as you get lower. If you do your snap rolls on takeoff in a T-6 (Harvard) you have few feet for margin of error. You'd better be as good as Bud Granley. Or doing a roll at perhaps 100 feet after takeoff like Elliot Cross did in the Spitfire at Oskosh, you have to be good, there is just so little room for error. I am not as good as these folks, I leave more room. I have had a low altitude acro permit since I got it from the FAA in a CAF show in 1987. My limit is 500 feet, I don't need do do it any lower. There is a little wiggle room there, if I were to loose a few feet coming out of a roll a little nose low. There is just no margin at 50 feet. I don't practice hours daily all week long like the top folks do.
Another factor is what type act you do. The farther you get from normal flight the more it takes to recover. A simple roll is not that big a departure from a steep turn, just more so. You need to keep the nose above or around the horizon and start with the correct entry speed and most of all not pull Gs when inverted. But the normal progression, given room will bring you back to level flight. Looping maneuvers are more "abnormal", anything vertical involves the potential for a stall at the top or over g or a dive into the ground at the bottom. If it involves an intentional stall/spin, then you have in effect moved from "flying " to "falling" , and have to do a little more to get back to normal flight. This "little more" may take more skill and if anything goes wrong, make need more time/altitude to recover.
This has gotten longer than I intended and I haven't covered types of planes yet.
The point I am trying to make is be very careful, If you do this stuff down low it is not good enough to be right most of the time. It's not like being a winning pitcher in baseball with a 20-10 record.
And don't do it at all with a passenger unless you have lot's of air under your and that means thousands of feet, not hundreds.
Re: Safety and Warbird Acro
Wed Nov 04, 2009 12:48 pm
Bill Greenwood wrote:If you do this stuff down low it is not good enough to be right most of the time.
This sounds right on Bill!
It is a shame that we loose many people every year just because they were "wrong" that one time...
Wed Nov 04, 2009 12:58 pm
Well written! How many of us have pushed our cars a little too fast to stop or corner, bumped a curb or gone in the ditch! You do that in an Aircraft and there may be no "Next time"! Down low there is NO room for error. Plan it, think it, practice it, fly it.
Wed Nov 04, 2009 1:06 pm
Basically, all these combat aircrafts were not designed to make funky manoeuvers at low altitudes, but to fly as fast and to hit as hard as possible.
That's why, in meetings, I don't like to see rare and old aircrafts flying in a way they were not conceived for.
High and slow, ok.
Fast and low, ok.
But low and slow with such aircrafts, not ok.
That's why, in meetings, I don't like to see rare and old aircrafts flying in a way they were not conceived for.
High and slow, ok.
Fast and low, ok.
But low and slow with such aircrafts, not ok.
Wed Nov 04, 2009 1:18 pm
Agreed. I love the site and sound of a warbird aircraf flying in the air however, once I see the pilot showing off their skills in it my first thought is always, why risk such a beautiful and precious machine. Go do the aerobatics in a Pitts instead. That way my kids, and their kids will be guranteed a glimpse at this artifact of the past in it's proper elemtn, flying.
Safety and Warbird Acro
Wed Nov 04, 2009 2:00 pm
Perhaps I overstated my case. I don't mean that warbird pilots or planes should not do acro. I am just saying that if it is done down low, say hundreds of feet instead of thousands, then there is extra risk and THAT HAS BEEN THE CAUSE OF MOST OF THE FATAL WARBIRD ACCIDENTS IN THE 25 YEARS THAT I HAVE BEEN INVOLVED IN IT.
So be very careful when doing it. Not only train and practice, but maybe add some extra margin below you which gives a little more cushion in time and altitude to recover. You can also tailor your choice of maneuvers to fit your ability as well as the type of plane you are flying. I use 500' as a minimum and I start only at the correct entry speed, (206Kmin) for my plane, and on a climbing arc. I don't do verticals or spins down there.
AND MOST OF ALL, DON'T DO IT WITH PASSENGERS DOWN LOW.
So be very careful when doing it. Not only train and practice, but maybe add some extra margin below you which gives a little more cushion in time and altitude to recover. You can also tailor your choice of maneuvers to fit your ability as well as the type of plane you are flying. I use 500' as a minimum and I start only at the correct entry speed, (206Kmin) for my plane, and on a climbing arc. I don't do verticals or spins down there.
AND MOST OF ALL, DON'T DO IT WITH PASSENGERS DOWN LOW.
Wed Nov 04, 2009 2:19 pm
I hate to see acro in the hundreds of feet range in any warbird with any pilot. It doesn't matter how good you are if you loose your engine at the top of a loop with little margin for error you're toast and a piece of history is destroyed. Go buy a pitts, extra, decathlon etc that isnt 60 year old and unforgiving. Well said, Bill. good to see you back.
I never do wifferdills with passengers..
Wed Nov 04, 2009 10:43 pm
...period. I personally feel that those kinds of things are only fun for the guy doing them and I simply refuse if someone asks. of course my opinion and $1.50 will get you a small coffee at any strarbucks.
Thu Nov 05, 2009 3:20 am
THAT HAS BEEN THE CAUSE OF MOST OF THE FATAL WARBIRD ACCIDENTS IN THE 25 YEARS THAT I HAVE BEEN INVOLVED IN IT.
I've personally been in the back of a T6 doing limit turns at 50 feet with a 55 yr old 25,000 hr pilot flying , he was a great pilot but everyone has an off day , at the time I was thinking to myself that if anything happens it will be over quickly , not fun , there was absolutely no margin for error and at that moment I didn't want to be sitting in the back of that particular T6 ... and no intercom either to express my displeasure !
When the owner of the aircraft heard about it he wasn't happy either
Sometimes ego and adrenalin can get to the best of us.
Last edited by aseanaero on Thu Nov 05, 2009 3:40 am, edited 3 times in total.
Thu Nov 05, 2009 3:26 am
double post ...
Thu Nov 05, 2009 3:45 am
triple post ... sorry
Thu Nov 05, 2009 6:35 am
What are "limit turns"?
Thu Nov 05, 2009 6:41 am
High speed max angle of bank turns at about 70 to 80 degrees angle of bank up until you start hitting a stall buffet
Safety and Warbird Acro
Thu Nov 05, 2009 11:51 am
Another safety factor is the type of plane used; how does it behave in acro or near g limits?
I think the safest warbird acro I ever saw was a Curtiss Jenny at a California airshow years ago. The pilot did an intentional spin STARTING AT 1000 FEET! He did two turns and easily pulled out above 600 feet. That thing must have had the wing loading of a hummingbird, and it operated as if it was in another dimension. It probably weighed 1600 lbs or so and had two big sets of wings to support it. The max speed was probably 90mph and stall probably 30mph.
The opposite might be some jet with high speeds and very high wing loading. Or in prop warbirds something like a B-26 with high speed, high wing loading and the added factor of two engines needed to support it. Of course one can be skilled enough, like Bob Hoover in the Shrike, to do a show even in this kind of plane if you are very careful about your airspeed margin and g loads.
Some airplanes have very docile stall behavior and lot's of warning like a 220 hp Stearman or a Merlin Spitfire, thus flying close to g/stall limit is a little easier than perhaps a Mustang or FW 190, with less stall warning.
I don't have much direct experience or knowledge of the pure acro planes like Pitts, Sukoi, Extra, etc. I do know quite a few have come to grief even with highly skilled pilots.
I think the safest warbird acro I ever saw was a Curtiss Jenny at a California airshow years ago. The pilot did an intentional spin STARTING AT 1000 FEET! He did two turns and easily pulled out above 600 feet. That thing must have had the wing loading of a hummingbird, and it operated as if it was in another dimension. It probably weighed 1600 lbs or so and had two big sets of wings to support it. The max speed was probably 90mph and stall probably 30mph.
The opposite might be some jet with high speeds and very high wing loading. Or in prop warbirds something like a B-26 with high speed, high wing loading and the added factor of two engines needed to support it. Of course one can be skilled enough, like Bob Hoover in the Shrike, to do a show even in this kind of plane if you are very careful about your airspeed margin and g loads.
Some airplanes have very docile stall behavior and lot's of warning like a 220 hp Stearman or a Merlin Spitfire, thus flying close to g/stall limit is a little easier than perhaps a Mustang or FW 190, with less stall warning.
I don't have much direct experience or knowledge of the pure acro planes like Pitts, Sukoi, Extra, etc. I do know quite a few have come to grief even with highly skilled pilots.
Thu Nov 05, 2009 7:00 pm
aseanaero wrote:High speed max angle of bank turns at about 70 to 80 degrees angle of bank up until you start hitting a stall buffet
Well, there are certainly stupid things that pilots do which transcend aircraft category, class, or type.
That being said, flying a high performance airplane near it's limits down at low altitude -- while inherently dangerous -- isn't necessarily wrong or stupid. It all depends on the reason.
Everybody that straps on an airplane accepts a certain level of risk. That level of risk depends on an infinite number of different factors.
If you really want to be "safe" -- don't fly. If you really don't want to risk a historic airplane -- don't fly it.