scsmith
Well Known Member
A Tale of Two Airplanes
This is a story about two airplanes, or rather, two stories about airplanes. At the end, I will voice some ideas for you to think about.
The first story is about an RV-8. This beautiful airplane was enjoyed by its owner for many hours; its home airport in the pacific northwest was paved, but narrow, and lined with well-manicured grass on both sides. One winter, the owner decided to sell this very nice example of what many of us regard as a fantastic airplane. I forget why – maybe he decided to build another.
Anyway, on this particular day, the owner was demo'ing the airplane to a prospective buyer. They departed the home airport and did some flying around, stopping at another airport for lunch. By the time they finished lunch, it was stormy and windy. They flew back to the home airport to find it very windy, very gusty, and it had rained, so the paved runway was soaked and the grass was slick.
The owner wasn't overly concerned about the gusty crosswind. This was his home airport, and he had lots of practice with strong cross winds there. He flew an approach with some extra speed margin for the gusts, did a careful wheel landing ( first the right, then the left). He was really attentive as the airplane slowed and he let the tail wheel down. There. All is well.
But he didn't let his guard down; there's a reason why they say you fly a taildragger until its parked. As he let the speed bleed down, he was careful to keep the airplane on centerline, straight, stick all the way back. About the time he was slowing through 25 or 30 mph, a very strong gust hit from the right. Zing! Just like that, the tailwheel broke traction, the airplane yawed violently to the right and started sliding. Both main wheels were sliding on the wet pavement until the airplane drifted off onto the grass. The right wheel slipped easily on the slick grass, but when the left wheel left the pavement, it sank into the soggy grass and dug in. Umph, the plane stopped. The left landing gear tower tore out of the floor and twisted grotesquely, the left wingtip came to rest on the grass. His beautiful airplane was now seriously damaged. The owner chided himself for perhaps being a little slow to move his feet up onto the brakes, maybe he would have been able to correct the slide in time.
I didn't make this story up – it really happened. I may have gotten some details wrong, but the salient points are true. **(edit: I'm embarrassed to have to say that I realized after I wrote this that I unintentionally have merged two separate incidences - the damage in the incident described here was not catastrophic, and apparently the gear retention bolts failed, perhaps preventing other damage- a good thing. I have examined detailed photos from two other incidents in which the gear tower was torn loose, twisted and much of the surrounding fuselage badly damaged)**
The rest of this paragraph is my speculation: it would not have mattered if the pilot was quicker on the brakes. The hard, smooth rubber tail wheel lost traction on a gust and the airplane yawed very quickly.. The runway was so wet the main wheels were sliding – brake application would have done little or nothing. It might be that a pneumatic tail wheel with some tread on it might have prevented the accident, I don't know.
The second story is about a Cessna 180 Skywagon. It happens that this particular Skywagon had been fitted with the P-Pong after-market landing gear reinforcement system. The owner was flying under IMC over the central valley of California, when the engine quit. Instantly quiet. Emergency engine-out procedures were followed, no joy. He told ATC he was descending, and turned away from the suburban area he knew he was approaching, retreating toward open farm country. He broke out of the clouds at 1500 ft. Lots of very soggy, half-flooded fields of crops, divided by a grid of muddy farm roads. He picked a road that was more-or-less into the wind, checked for wires while on downwind, turned base and noticed that the road was elevated from the fields on either side by several feet. It was narrow, but quite landable.
The pilot flew a wheel landing to maintain good visibility on the road as he touched down. He could tell immediately that the road was very slick with mud. He worked hard to keep the airplane headed straight as he slowed down. Tail wheel came down, all OK so far. At a certain point, he just could not keep it on the road, and it slid over the edge and down the slope into the drainage ditch alongside the road. It slid until the left wheel got to the bottom of the slope and stuck in the muddy drainage ditch. Umph, the plane stopped. The owner got out and was pleased, even a little surprised to find the landing gear apparently intact. The farmer showed up with a truck, pulled the plane out of the ditch and back to a dry barn to check things over.
The landing gear was fine. The engine stoppage was determined to be from a plugged carburetor jet, from a small flake of orange RTV that somehow got inside the carburetor. When the carburetor came back from the rebuilder, it was bolted back on and the airplane took off from the same road it had landed on the previous week, and flew home.
I didn't make this story up – it really happened. I may have gotten some details wrong, but the salient points are true. The rest of this paragraph is my speculation: The P-pong landing gear reinforcement may have saved the airplane. Perhaps the original stock Cessna landing gear would have survived too, I don't know. Skywagons are pretty tough birds. And with the availability of some well-thought-out modifications, they can be even better than new.
Some thoughts:
First of all, I do NOT understand the view expressed by some that Van's airplanes are perfect, and you are an idiot if you suggest changing it to perhaps make it better. I have nothing but respect and appreciation for Van and his team for developing such successful kit airplanes that are superior to many production airplanes. Special kudo's to Ken Kruger, who I believe did the majority of the detailed design work on the –8. It is a magnificent airplane, to be sure. But that doesn't mean there aren't some places for improvement.
What if some simple reinforcement was available for the RV-8 landing gear that substantially increased its strength in a couple of critical areas, and added just one pound to the empty weight? Its not possible to make any landing gear failure-proof. Subjected to enough violence, anything will break. But what if the reinforcement was just enough extra strength to save the poor fellow in the first story from the despair of breaking his beautiful airplane?
Some people would say this is a solution without a problem because every failed gear on an RV-8 is from pilot error. Some would say that Van knows best and it would be foolish to try to make the –8 better. I say that I have studied more than one gear failure, and I have studied the structural design, and I think a simple parts substitution during construction can make a big difference to the strength of the landing gear, at the cost of just about one pound of weight.
I started from a quick-build kit, and the assembly was far enough along that I was not able to incorporate my ideas into my airplane. When I build the next one, I will do it. If you think I'm wasting my time and breath, fine. I don't need to hear from you. If you are building an RV-8 fuselage and you have not yet attached the subfloor parts to the inner floor and bottom of the gear towers, and you think you would like to add some strength, send me a PM.
This is a story about two airplanes, or rather, two stories about airplanes. At the end, I will voice some ideas for you to think about.
The first story is about an RV-8. This beautiful airplane was enjoyed by its owner for many hours; its home airport in the pacific northwest was paved, but narrow, and lined with well-manicured grass on both sides. One winter, the owner decided to sell this very nice example of what many of us regard as a fantastic airplane. I forget why – maybe he decided to build another.
Anyway, on this particular day, the owner was demo'ing the airplane to a prospective buyer. They departed the home airport and did some flying around, stopping at another airport for lunch. By the time they finished lunch, it was stormy and windy. They flew back to the home airport to find it very windy, very gusty, and it had rained, so the paved runway was soaked and the grass was slick.
The owner wasn't overly concerned about the gusty crosswind. This was his home airport, and he had lots of practice with strong cross winds there. He flew an approach with some extra speed margin for the gusts, did a careful wheel landing ( first the right, then the left). He was really attentive as the airplane slowed and he let the tail wheel down. There. All is well.
But he didn't let his guard down; there's a reason why they say you fly a taildragger until its parked. As he let the speed bleed down, he was careful to keep the airplane on centerline, straight, stick all the way back. About the time he was slowing through 25 or 30 mph, a very strong gust hit from the right. Zing! Just like that, the tailwheel broke traction, the airplane yawed violently to the right and started sliding. Both main wheels were sliding on the wet pavement until the airplane drifted off onto the grass. The right wheel slipped easily on the slick grass, but when the left wheel left the pavement, it sank into the soggy grass and dug in. Umph, the plane stopped. The left landing gear tower tore out of the floor and twisted grotesquely, the left wingtip came to rest on the grass. His beautiful airplane was now seriously damaged. The owner chided himself for perhaps being a little slow to move his feet up onto the brakes, maybe he would have been able to correct the slide in time.
I didn't make this story up – it really happened. I may have gotten some details wrong, but the salient points are true. **(edit: I'm embarrassed to have to say that I realized after I wrote this that I unintentionally have merged two separate incidences - the damage in the incident described here was not catastrophic, and apparently the gear retention bolts failed, perhaps preventing other damage- a good thing. I have examined detailed photos from two other incidents in which the gear tower was torn loose, twisted and much of the surrounding fuselage badly damaged)**
The rest of this paragraph is my speculation: it would not have mattered if the pilot was quicker on the brakes. The hard, smooth rubber tail wheel lost traction on a gust and the airplane yawed very quickly.. The runway was so wet the main wheels were sliding – brake application would have done little or nothing. It might be that a pneumatic tail wheel with some tread on it might have prevented the accident, I don't know.
The second story is about a Cessna 180 Skywagon. It happens that this particular Skywagon had been fitted with the P-Pong after-market landing gear reinforcement system. The owner was flying under IMC over the central valley of California, when the engine quit. Instantly quiet. Emergency engine-out procedures were followed, no joy. He told ATC he was descending, and turned away from the suburban area he knew he was approaching, retreating toward open farm country. He broke out of the clouds at 1500 ft. Lots of very soggy, half-flooded fields of crops, divided by a grid of muddy farm roads. He picked a road that was more-or-less into the wind, checked for wires while on downwind, turned base and noticed that the road was elevated from the fields on either side by several feet. It was narrow, but quite landable.
The pilot flew a wheel landing to maintain good visibility on the road as he touched down. He could tell immediately that the road was very slick with mud. He worked hard to keep the airplane headed straight as he slowed down. Tail wheel came down, all OK so far. At a certain point, he just could not keep it on the road, and it slid over the edge and down the slope into the drainage ditch alongside the road. It slid until the left wheel got to the bottom of the slope and stuck in the muddy drainage ditch. Umph, the plane stopped. The owner got out and was pleased, even a little surprised to find the landing gear apparently intact. The farmer showed up with a truck, pulled the plane out of the ditch and back to a dry barn to check things over.
The landing gear was fine. The engine stoppage was determined to be from a plugged carburetor jet, from a small flake of orange RTV that somehow got inside the carburetor. When the carburetor came back from the rebuilder, it was bolted back on and the airplane took off from the same road it had landed on the previous week, and flew home.
I didn't make this story up – it really happened. I may have gotten some details wrong, but the salient points are true. The rest of this paragraph is my speculation: The P-pong landing gear reinforcement may have saved the airplane. Perhaps the original stock Cessna landing gear would have survived too, I don't know. Skywagons are pretty tough birds. And with the availability of some well-thought-out modifications, they can be even better than new.
Some thoughts:
First of all, I do NOT understand the view expressed by some that Van's airplanes are perfect, and you are an idiot if you suggest changing it to perhaps make it better. I have nothing but respect and appreciation for Van and his team for developing such successful kit airplanes that are superior to many production airplanes. Special kudo's to Ken Kruger, who I believe did the majority of the detailed design work on the –8. It is a magnificent airplane, to be sure. But that doesn't mean there aren't some places for improvement.
What if some simple reinforcement was available for the RV-8 landing gear that substantially increased its strength in a couple of critical areas, and added just one pound to the empty weight? Its not possible to make any landing gear failure-proof. Subjected to enough violence, anything will break. But what if the reinforcement was just enough extra strength to save the poor fellow in the first story from the despair of breaking his beautiful airplane?
Some people would say this is a solution without a problem because every failed gear on an RV-8 is from pilot error. Some would say that Van knows best and it would be foolish to try to make the –8 better. I say that I have studied more than one gear failure, and I have studied the structural design, and I think a simple parts substitution during construction can make a big difference to the strength of the landing gear, at the cost of just about one pound of weight.
I started from a quick-build kit, and the assembly was far enough along that I was not able to incorporate my ideas into my airplane. When I build the next one, I will do it. If you think I'm wasting my time and breath, fine. I don't need to hear from you. If you are building an RV-8 fuselage and you have not yet attached the subfloor parts to the inner floor and bottom of the gear towers, and you think you would like to add some strength, send me a PM.
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