Why not? Hey, the experimental in homebuilt experimental aircraft means just that - experimenting. There is absolutely no law or regulation forbidding the builder of such an airplane from making extensive deviations from the original design either while building it or later, after construction. For that matter, there is a person just over the state line from me who designed and built an airplace from scratch (it’s a pretty good one, too, called a “Breezy”) without the aid of an “expert”. He’s been flying it safely for about 30 years now. In fact, that airport has a good-sized group of amateur builders, a couple of whom I’ve flown with. You can go there, see 4 or 5 RV-6 kit planes lined up, and if you start looking you start seeing each and every one seems to have something significantly different - a different shaped rudder, or a different set to the landing gear, or a different canopy construction…
Oh, about that Breezy - do NOT get it into a full stall unless you’re at least 8000 feet - it takes at least a half mile to recover it to normal flight. Why? I don’t know. But it does. Neither does the designer. Other than that, it behaves pretty much like a convetional airplane. See, experimentals can bite you like that - perfectly normal until you hit a particular weirdness.
There is absolutely nothing to prevent another pilot from building an E-Z today with the fuel selector in a different location than Rutan intended. Next time, it might be overhead, or on the right. Would be pretty dumb to do that, but the FAA will allow you to kill yourself in an airplane - their main concern is that you not kill anyone else in it or with it.
Homebuilts don’t have ADs. Mainly because each one is unique.
WHY would they do this? What possible motivation would the NTSB have to deny a birdstrike? This makes zero sense, unless you’re preposing a seabird conspiracy. Are you?
Have you ever seen an EZ up close? Touched one? Maybe even sat in one?
I’ve helped pull one out of a hanger and helped the pilot pre-flight and set up to fly. I not only saw the same plane after it crashed, I handled some of the pieces. (Charming conversation in the hangar - “Zeke, you think we can salvage this seat belt?” “Naw – we’ll never get all that blood out of it…”)
Let’s start with a very basic concept - an E-Z travels fast. Landing speed is around 100-110 mph (large variation because, being homebuilts, they vary a lot) - that’s after it has slowed down from cruise. The guy who smashed his up in my area had already landed and was probably under 100mph when he wrapped it around the light pole. Fiberglass may be strong, but the shell on an E-Z is thin to keep the weight down and is there more for streamlining purposes than anything else. The fuselage, as I said before, shattered. We’re not talking about something as sturdy as a boat hull. When getting into a small plane of this sort you want to step carefully because if you don’t you can and will punch through the skin of the airplane.
Now, Denver’s plane was in flight, well over 100 mph even if he was “low and slow” in the traffic pattern. Hitting a solid object with that plane in flight (and, at those speeds, water is more solid than liquid for impact purposes) would guarantee the fiberglass body would break up. When it does, it breaks up into very sharp-edged pieces. For our local wreck, the salvagers handling the fuselage fragments wore heavy gloves to prevent serious cuts - hitting an edge like that would be like falling on a meat cleaver.
Now, the airplane doesn’t care which way it’s nose is pointed. There is no magically ground-detecting wing. If it can fly straight and level at 150 mph (as an example) there is no reason it won’t happily fly 150 mph (and then some!) with the nose pointed straight down towards the center of the earth. Add an engine and some gravity you can build up a fearsome rate of speed in a very short time. Any airplane can be pointed nose down and generate enough speed - without a stall - to physically rip the wing off the airplane. This can be done even with a glider, that is, without any engine at all you can use gravity to build up enough speed to destroy your airplane. An airplane is an inanimate object - it does what you tell it to, even if that’s not what you intend. Denver didn’t have to stall to crash - he only had to put the wrong control input in, get the nose pointed down, and do it so low he simply had no time to fix the problem.
Get your facts in order. Yes, spatial disorientation is the official cause of JFK, Jr.'s death. But it was NOT a clear night! It was foggy, misty, and hazy, with minimal VFR visilities (3-5 mph) at best… There was no starlight or moonlight to reflect, and only the distant lights of Martha’s Vineyard to see - if that.
Yes, it is. Life expectancy of a pilot without instrument training flying into instrument-requiring conditions is under three minutes.
VFR pilots are given minimal training in this sort of flying, with the idea that it might save a life to know something, and it has, but a lot of people have been killed over the year by harmless-looking white fluffy clouds. Me, the time I screwed up and found myself in this situation I opted to land in someone’s backyard rather than continue the flight.
I know it’s poor form to post without reading the entire thread, but I’m going to do it.
I also didn’t read the whole NTSB report. However, I did read this part:
I read a letter in a flying magazine from a Long-EZ pilot. IIRC, he had the fuel selector located in the same place as the crash airplane. He said that the act of twisting the seat caused him to inadvertantly press on the right rudder pedal. This resulted in putting the aircraft into an unstable position. Obviously, he was able to recover. But he had power. From what I read not long after the crash, it seems as if this is the likely scenario: The engine suffered fuel starvation and left the aircraft without power. Denver reached around to switch tanks. In doing so, he inadvertantly pressed the rudder pedal. This yawed the aircraft and put it into an unusual position. Without power, Denver was unable to recover from the unusual position. I’ll read the NTSB report after I get some caffeine in me.
Sam Stone says that was a “human factors error”. I still lean toward pilot error, since a pilot should always insure there is enough fuel in the aircraft for the completion of his flight.
His plane went down right next to one of my surf spots here in the Pacific Ocean not far from land. Alot of people think it went down near Lover’s Point, but actually it was near Asilomar blvd. I have to agree with Broomstick that he flew into the water at a high rate of speed, but was there water in his lungs? Wouldn’t the fact he was under water be a factor?
Not if his head was ripped off. The autopsy showed that he died of blunt trauma. I doubt he would have been able to take a breath, putting water in his lungs.
A note about Long EZ (and VariEze – pronounced “very easy”) construction. The are built much like surfboards. There is a foam core sandwiched between layers of fiberglass. This results in a strong, lightweight structure that is said to be easier to work with than aluminum. I have a video in storage that I got at RAF that demonstrates the strength of the structure. A canard was built, half of it in the foam/fiberglass construction and the other half in the traditional aluminum construction. Burt Rutan and his test pilot and co-builder (whose name escapes me at the moment) supported it on cinder blocks and jumped on it. The aluminum section was smashed. Then they put the foam/fiberglass construction on the blocks and they both stood on it, bouncing a little. It remained intact.
Broomstick is right though, that the airframe itself is like an egg shell. It’s very strong, but once it breaks it can shatter.
I went back and read the NTSB report. It said that the calculated CG was at 110 inches. Scaled Composites says that the aft limit was 103 inches (although they tested it at 104). In an aft-CG situation, an aircraft may become unrecoverable in a stall. Now, a Long EZ is not prone to stalling; it was designed not to stall. But an aft-CG situation combined with an inadvertant deflection of a control surface while the pilot is pre-occupied by a sputtering engine is a recipe for disaster, which was to be demonstrated.
Far be it from me to continue a hijack, but I wanted to emphasize something Broomstick said:
I was staying at a hotel on the water on Long Island Sound (Water’s Edge in Westbrook, CT, FTR) the night JFK Jr.'s plane went down. I remember waking up to the sound of a CH-47 flying low and slow along the coast. It wasn’t until around noon that I found out why.
That evening, my wife and I were walking around the grounds. Although there weren’t any clouds above, there was a thick haze over the water. That haze persisted until well into the late morning. As two data points, a small island about 100 yards offshore that I was later able to wade to was not visible from shore that night or in the morning. Also, the various aircraft (the CH-47 was only one of about 5 military ones I saw that AM) that flew overhead were very difficult to make out. The offshore haze definitely obscured them and extended for some distance upward.
This is all corroborative to the Meteorological Information section of the NTSB accident report. I thought that a personal perspective might be appreciated in this context.
I just wanted to comment that the designer may have nothing to do with the engineering of said plane. Afterall, didn’t McDonnell Douglas take their lumps for the DC-10 design, for example? Now, is it a faulty design, or is it poor engineering? In some cases, these two words may be one and the same depending on just how far the designer takes a design into production. Consider Frank Lloyd Wright’s dream designs, but someone has to actually build it and make it work. In short, fauty design could refer to the actual construction, too. If it were a faulty weld holding an airframe together, for example, it is possible that the weld called out on the blueprints was not the right choice OR the welder did not perform the welding job up to standards.
Splitting hairs, but even the greatest genius can be sunk by this!
For those who support the seabird conspiracy theory, I spoke with a few pilots after Mr. Rocky Mountain died, and they all said, best I can recall, exactly what Broomstick says. Being professional airline pilots former military gods, they tended to be a little more harsh.
The Onion reported that significant amounts of sunshine were found in Denver’s system, in and around the area of his shoulders. The medical examiner said the levels were more than enough to have made him high.
"They scooped up what they could find in multiple garbage bags, but what was left weighed only 128 pounds. Here’s a list of what ended up forever fish food:
His brain, his teeth, his eyes, for that matter, 75% of his head was missing. Also gone were his right hemipelvis, and right thigh, one lung and his gallbladder. His left arm was missing, but they found it an hour or so later."
Thank you handy for that Gratuitous Gore post. Where’s my barfing smiley? We really need on for this crowd.
Personally, I thought “his head was ripped off” was plenty explicit enough, I really did not need an organ by organ recitation of missing body parts. Couldn’t you have just stopped with the link? Maybe used a spoiler box?
BTW - just to get back somewhat on track - perhaps Sam Stone or someone else with a little better grasp of aerodynamic engineering might wish to explain why a bunch of us out here are saying things like “you can’t stall a canard.” For that matter, you might want to mention we’re not talking about engines stalling but wings. And what a canard is As a pilot, I know why canards are “stall-proof”, but I know I’d bungle the explanation trying to put it into layman’s terms.
IANAAE, but here’s how I understand it. If a canard aircraft is approaching an airspeed and attitude combination that would stall a conventional airplane, the canard stalls. This lowers the nose before the wings reach the critical airspeed/attitude configuration.
This doesn’t mean that you can’t stall a canard, but that a properly designed canard-configured aircraft should be more stall resistant than an aircraft with a conventional layout.
Incidentally, this is a Long EZ. The pods you see under the wings are not fuel tanks (as on fighter jets), but cargo pods. According to the NTSB report, Denver’s aircraft was fitted with pods; but I’d have to re-read it to see if it says if they were attached during the last flight.
The reason you see no nosewheel is that it is retractable to reduce drag. The nosewheel is also retracted for parking, which keeps the aircraft from tipping backwards.
Canards are stall resistant - if built correctly. The reason that Velocity now sells their kits with pre-formed wing cores is because a fellow managed to put his plane into a deep stall - twice. The second was fatal.
But yes, the canard (the little wing out front, just like the Wright flyer) is designed to stall (stop producing lift because it’s angle of attack (pitch relative to the wind) is too great) before the wing, thereby causing the nose to drop, thus preventing the wing from getting its AOA high enough to stall.
Think of when you were a kid and stuck your hand out the car window, palm down - remember altering the pitch of your hand, and if you got it too high, the wind would whip it backwards? That is the kind of thing an aerodynamic stall is.
(not bad for someone who knows nothing about planes, huh?)
The simple answer is that the canard is designed to have a lower critical angle of attack than the main wing. So the canard stalls before the main wing does, and the nose drops.
In a conventional aircraft, the center of lift of the wing is behind the center of gravity. Therefore, without a tail, the aircraft would want to pitch over on its nose. A conventional tail therefore creates negative lift - it is designed to push the back of the airplane down to keep the nose up. When set up right, this causes the airplane to be stable - if the plane slows down, the tail force decreases, the nose pitches down, and the airplane accelerates back to its trimmed speed. If the plane goes too fast, the tail pushes down more, and pulls the nose up.
The problem with a conventional tail is that it is creating a downforce acting against the lift of the wing, which makes the wing have to work harder to keep the airplane aloft. That causes an increase in induced drag, and makes the airplane a little less efficient.
A canard is fundamentally different, in that both the canard and the wing create positive lift. Think of the airplane as being supported on both ends by a column of air. Because both surfaces create lift, the canard is theoretically more efficient. And because both create lift in the same direction, and both have a positive AOA all the time, you can set them up so that the canard stalls first when the nose is raised. So the nose falls forward, the canard gains lift, the nose comes up, the canard stalls, etc. The main wing never stops flying. In a properly set up canard airplane, holding the stick back in your lap will result in the thing bobbing along like a sick duck, but still flying.
So why aren’t all airplanes canards? There are a number of reasons - like anything in aviation, there are no perfect solutions. One of the problems with a canard design (maybe the biggest problem) is that they need lots of runway and land very fast. Again, because the canard stalls before the wing does, you have to fly the airplane onto the runway. In a conventional airplane, you can do a full-stall landing and use the maximum lift capability of the wing. No can do in a canard airplane.
Another problem is where to put the engine. Canards need nice smooth uninterrupted airflow, so you don’t want to stick one behind a propeller. So most canard aircraft have their engine in the back, and that creates a number of design headaches - everything from cooling to propeller strikes to strange pitch behaviour when power is applied.
Finally, there are conditions under which you can stall a canard. Several canard aircraft have suffered from ‘deep stall’ problems. Basically, what happens is that the wing design that is usually dictated by a canard (swept back aft wing) can set up a situation where at an angle the Cg of the airplane actually moves behind the center of lift. So even though the canard stalls and stops flying, the nose won’t come down.
There’s an airplane called a ‘Velocity’ that had this problem. I remember reading an accident report where the pilot got into a deep stall, and tried everything he could to get out of it, including opening the door of the plane and trying to climb out into the nose to help it go down. Nothing worked, so he sat back down, and realized that he was only descending at a few hundred feet per minute (a deep stall in this airplane was a very high drag situation). So basically he just buckled up, braced himself, and waited for impact. The airplane went SPLAT in shallow water just offshore, and the pilot got out completely uninjured. And the airplane was towed in and flew again.
And I’m sure that’s more than anyone in this thread wanted to know about canards!
Johnny: I prefer ‘human factors’ to ‘pilot error’ when there are mitigating circumstances like this, because it helps to get the idea across that pilot error isn’t quite as cut-and-dried as it sounds.
For instance, if I designed an airplane with the gear lever right beside the flap handle, but wired so that the gear was ‘down’ when the lever was ‘up’, I can guarantee that that airplane would have far more than its fair share of accidental gear up landings. Sure, if a pilot carelessly reaches over and flips the gear switch instead of the flaps, it’s ‘pilot error’. But just saying that masks the fact that there is a real flaw in the design of the airplane.
In the case of John Denver’s Long-EZE, the placement of the fuel selector was a usability nightmare. It ensured that the pilot put himself in a very difficult position to fly the airplane, at a time when he most needs to fly.
Now sure, one can be supremely careful with fuel management, practice constantly, and make that fuel selector as safe as anything else in the airplane. But the design gets in your way.
Human factors is an interest of mine, and also part of my job (usability of software). I highly recommend a book called The Design of Everyday Things, which is a great introduction to this stuff.
For example, consider how many times you’ve pushed on a door that you were supposed to pull. Often, the door will just have a bar on each side which can be pulled or pushed. With such a door which doesn’t give you natural cues as to its function, no amount of signs saying PUSH or PULL will stop people from pulling when they should push or pushing when they should pull. It’s too hardwired in us. But put a pulling handle on one side, and a push plate on the other, and suddenly we all ‘get it’ and never made that mistake. Simple things.
Homebuilt aircraft are human factors disasters. It’s usually the last thing an amateur builder considers, especially when he’s making the airplane for himself. That complicated latch mechanism is intuitively obvious in function - to the guy who designed and painstakingly built it. To everyone else, it may be a nightmare, and when you need to get out of your airplane in a hurry, that strange latch mechanism will thwart you.
Airplanes are usually very good at human factors, because designers have studied it for years. Take a simple throttle control - push forward, go forward. Pull back, slow down. Imagine if the throttle was a dial that you turned right and left instead. You’d have to think about which way to turn it all the time. And imagine if half the airplanes you flew had counterclockwide = more power and the other half did the opposite. Sure, pulling the power by accident when you need to apply it is pilot error, but it’s understandable.
In homebuilts, this happens all the time. And that’s what killed John Denver. Sure, the proximate cause was that he screwed up. But there really was a much larger issue.
This was actually a problem at one point during WW2, when the RAF took over a number of different American aircraft after the fall of France in 1940 from French Air Force contracts. The French used a throttle setup which worked in the opposite direction from the the British/American norm, and the A/C all had to be modified before RAF pilots could fly them safely.