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Van's over-engineering compared to certified aircraft

David Paule said:
"Over-engineering" is a rather vague term. To some it means over-strength and to others, it approaches the infamous "paralysis by analysis," excessive use of engineering time.

Are the RVs over-strength? Apparently not, from all I've read. They seem to be adequately designed for their mission, without a whole lot of margin. Remember, their mission includes being built by amateurs.

Has Van's wasted excessive engineering on them? Probably not, because they are still in business.

Dave
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Concur.

“Over engineered” means doing too much engineering. Definitely not a description on a Vans aircraft as prices are so reasonable there probably was not an excess of analysis or testing. In my day job we do lots more engineering to maximize performance and reduce risk. It is a cost vs performance trade.

“Over designed” is the correct terminology for making it stronger than it needs to be. Also not a trait of a Vans aircraft as performance shows low weight was high on the trade priority. Over designing is a weight vs performance trade.

Over engineered and over designed are related. If you want to do more engineering you are able to minimize material to meet the strength requirements. If you do not want to do the detailed analysis and over engineer, you tend to add some material to make up for the lack of analysis. Usually called conservative design and not over designed in the aero biz.

Over engineered and over designed are sliding scales that need to be judged for each airplane not compared across different designs. More analysis maybe required for very similar aircraft missions just based on construction material and methods.

The only place to really compare is in a cost vs performance vs risk trade. That is what the market does and based on sales, Vans must not be over engineered or over designed.
 
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Vans has good basic designs, simple, strong enough where they need to be and fairly efficient. I wouldn't say over engineered etc just adequate for the task at hand.
Remember AC revolved around one main criteria, weight which can be looked as ......more doesn't necessarily mean better:)
 
mfleming said:
I've heard people exclaim about Van's being overbuilt :eek:...but it's just not true IMHO.

My -7 is NOT over engineered, far from it. It's a great aircraft but the total performance comes from the light weight design. Some Beechcraft's may be considered over designed...they're built like a tank.
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Now that's a very true statement. I had a midair collision with a helicopter years ago in my Debonair; it smacked my right wing and ripped it open, but I was still able to make it back to the airport and make a "good landing" (The FAA's term for we walked away, but the airplane wasn't reusable).

The NTSB investigator's comment was, "that would have ripped through a Piper's spar, but Beechcraft, they're built like a bank vault." The Debonair, hence Bonanza and Baron's, the spar is a box design, so pretty stout.

Having built a couple RV's, currently a -10, and having owned several Beech's that I personally maintained, the RV's are pretty stout, but not the same structure as a Beech - if we're comparing wings and spars. They have thicker skin too on a Beech; mostly 0.032.

Now, comparing to the Zenith 601XL, my first build, there is no comparison to the RV in structural strength, IMHO.

Overall, I'd say RV's are a very well designed and engineered aircraft. Not overly engineered - just right.
 
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I think airplanes have to be broken down into flyability, reliability, durability and crashabilty.

No question in my mind the Vans aircraft are the best flying aircraft ever made for the general aviation public. They are faster, more fun to fly and less expensive than just about any aircraft produced today. They are truly a total performance airplane. I never worry about density altitude period. I hope to never sell my RV but one day?

Designed both using approved aircraft engines and construction procedures; they are simpler than most GA aircraft and very reliable. I do not hesitate to take a long cross country trip in my RV-4

Durability not so much. They are designed light for the above reasons. I have a Cessna 170 that has 7000 hours on the airframe and it still looks good. I give tail dragger instruction on a fairy rough grass strip and have dropped it in many times with no side effects. I would not give instruction in my RV-4 because it?s not durable enough. The gear is weak compared to a Cessna. I owned a Bonanza. I would run and jump on the wing flap. Try that in an RV. I never once worried about damaging any part of the Bonanza. It was built like a tank. RV-4, not so much, I have replaced cracked control surfaces after only a few hundred hours. I always land like a feather because firewall damage can and will result otherwise. Cracks on the firewall are ?normal. ?Compared to Cessna or a Beechcraft, I can?t imagine what it would look like if not handled gently after 7000 hours.

Crashabilty not so much. Thin metal bends easily. Not much steal or reinforcements surrounding a RV driver. As the above contributor stated, I much rather be in a Cessna than an RV in case of a crash. A friend of mine crashed landed his Cessna 210 in a field and slid through a fence. They hauled it out of the field and he was flying it a year later. Another friend of mine landed his Bonanza on a sandy beach. The gear sunk in the sand and he traveled less than 50 feet with no damage to the gear or airframe. Try that in an RV.

In summary, if you want a pickup truck get a Cessna, if you want a super fast fun to drive vehicle get a sports car, motorcycle or RV.
 
506DC said:
I think airplanes have to be broken down into flyability, reliability, durability and crashabilty.

No question in my mind the Vans aircraft are the best flying aircraft ever made for the general aviation public. They are faster, more fun to fly and less expensive than just about any aircraft produced today. They are truly a total performance airplane. I never worry about density altitude period. I hope to never sell my RV but one day?

Designed both using approved aircraft engines and construction procedures; they are simpler than most GA aircraft and very reliable. I do not hesitate to take a long cross country trip in my RV-4

Durability not so much. They are designed light for the above reasons. I have a Cessna 170 that has 7000 hours on the airframe and it still looks good. I give tail dragger instruction on a fairy rough grass strip and have dropped it in many times with no side effects. I would not give instruction in my RV-4 because it’s not durable enough. The gear is weak compared to a Cessna. I owned a Bonanza. I would run and jump on the wing flap. Try that in an RV. I never once worried about damaging any part of the Bonanza. It was built like a tank. RV-4, not so much, I have replaced cracked control surfaces after only a few hundred hours. I always land like a feather because firewall damage can and will result otherwise. Cracks on the firewall are “normal. ”Compared to Cessna or a Beechcraft, I can’t imagine what it would look like if not handled gently after 7000 hours.

Crashabilty not so much. Thin metal bends easily. Not much steal or reinforcements surrounding a RV driver. As the above contributor stated, I much rather be in a Cessna than an RV in case of a crash. A friend of mine crashed landed his Cessna 210 in a field and slid through a fence. They hauled it out of the field and he was flying it a year later. Another friend of mine landed his Bonanza on a sandy beach. The gear sunk in the sand and he traveled less than 50 feet with no damage to the gear or airframe. Try that in an RV.

In summary, if you want a pickup truck get a Cessna, if you want a super fast fun to drive vehicle get a sports car, motorcycle or RV.
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I like that, sums it all up nicely:):)
 
RV Bonanza etc

The round spring gear as designed by Steve Wittman is one of the strongest landing gears ever installed on a light airplane. The problem on the RV's is the fuselage area where the gear mounts. Having said that Rosie is approaching 5000 hours on the RV6 with no apparent problems.
 
Bonanza etc

If I were try to correct all the nonsense that has been posted here about Bonanza, Cessna etc, it would take a week. The Bonanza, Commanche, Lance and non strut braced 210's all have box spar wing center sections. The rest of the spars are channel sections or I section, NOT BOX SPARS.
The Bonanza main gear is very strong, the nose gear relatively fragile. Most single Cessna nose gears are fragile with the 182 having the worst record because of the weight on the nose. Piper is probably the best. If you do break a Piper nose gear it is by far the easiest repair of the three.
Of the first 1000 Bonanzas 100 crashed due to structural failures. Typically loss of control in IMC. Commanche is the safest in that regard.
The basic design of the Bonanza wing evolved to the outer wing panels of the Twin Bonanza, Queen Air and King Air. The basic Commanche wing evolved to the outer wing panels of the entire Cheyenne series.
I don't trust the structure of the Cessna 210. I don't like the wing attach design on the Beechcraft's except for the later model King Airs which are different.
To say that any of the above are built like a tank is absurd. Each has its own unique design features. Each has its own unique weaknesses.
 
In life we all tend to be much more influenced by what we see and experience rather than by what we read or are told. Let me tell you about my experience. Many years ago I was driving directly past Moorabbin Airport in Australia and I observed two aircraft crash on short final. It was a typical case of a low wing aircraft (a Piper Warrior) descending on top of a high wing aircraft (a Cessna 172). It was a violent impact at about 100 feet agl and the Piper immediately plummeted to the ground instantly killing the sole occupant. The Cessna however continued to fly (sort of) and pancaked onto the runway shearing off all of the landing gear. It then skidded on its belly on the asphalt for about a hundred metres before it came to a stop. The amazing thing was that the Cessna fuel tanks ruptured on first impact with the runway and the fuel caught fire. And the fuel continued to spew from the plane as it skidded along the runway. This created a wall of fire about 10 feet high that followed the skidding Cessna. But that wall of fire took about about 5 seconds to catch up to the aircraft after it came to a stop. And in those 5 seconds the pilot and his passenger were able to open their respective doors and bolt from the plane. And miraculously neither was burnt or badly injured. And then I saw the wall of flames catch up with the empty Cessna and it literally exploded in a ball of fire that went about 50 feet into the air. After it finished burning it was absolutely amazing how little of the plane remained....it was just a burnt engine and the rest of the fuselage and wings were just a completely melted mess of metal a couple of inches high. The whole plane just melted to the ground and was unrecognisable.
I saw this episode in its entirety with my own eyes and I was the sole witness of the entire event and ultimately gave a report to the Coroner?s Inquest. In my opinion the 2 occupants of that Cessna survived that crash because the aircraft exhibited amazing robustness, because the aircraft protected the occupants from impact injuries, because the aircraft did not flip inverted, and because the occupants were able to exit the aircraft through dual doors within seconds of the plane skidding to a halt.
So I always say that I love flying my RV7A....but I?d much rather crash a Cessna. And that is why I say it.
 
I dont dare throw my Super Viking into the debate:D. With it?s chrome moly steel tube frame and wings made from Sitka Spruce and Mahogany, I feel very safe in that airplane. The plane handles like an RV but is solid as an OX, smooth and quiet. I love that plane and a lot less delicate than an RV. Cruises fast, carry?s a load, only at the cost of fuel. Most notably much more solid landing and taxi feel than an RV.
 
Vikings

My cousin's husband landed in trees in a Viking near Clearwater, FL. They were forced to land due to an in-flight fire. He had some burns on his hand but he and the pilot got out with no other injuries. They credited that steel cage as having protected them.

I was having lunch with my cousin when she got word of the accident. Her husband called from the burning plane to say he loved her and that they were about to "crash land". All turned out well thanks to a well engineered airframe. John
 
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I?m seeing some confusion here between ?overengineering? and ?overbuilding?.
I generally associate overbuilding with under-engineering(or sloppy engineering). Van?s aircraft are all very elegantly engineered, taking into account ease of construction, practicality, amateur builder tolerance, and many other factors. They are neither overbuilt nor underbuilt.

This elegance of engineering should be respected and adhered to by builders. All of the essential structures are so well engineered that you are not likely to improve upon them with backyard modifications. Most particularly, resist the temptation to increase gross weight with a fountain pen, a truly egregious insult to Van?s brilliant work, and take CG and operating limitations very seriously. -Otis
 
Snowflake said:
On the other hand, the -7 was designed with a computer, and as such could be optimized at every point on the aiframe to meet the mission, with safety factors, and no more. .
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I doubt Van considered any more load cases than the basic ones on the 7. It's not because you use CAD that all of a sudden you can easily analyse every part of the structure for every load case. You would need a squad of people working for years. I suspect that CAD was used to aid in the manufacturing. He might have used it as the basis for some FEM (finite element analysis) or he might have just done all the same hand calcs that he did on the other airplanes. You would have to ask him. But don't assume that because there was a computer involved that they could do magic.

Also, on the Boeing vs Airbus front, there was a NOVA special on the 777 development. They should the static test to failure of the wing. There was a big clock showing the %limit load. They were shooting for 150% plus the tiniest little bit more. It failed at 152% of limit load, so they passed. If they failed at 160%, or more, like the people who think that Boeings are stronger claim, then the airplane would be too heavy and it wouldn't be competitive. Every lb you add is a lb less of fuel or payload. So no, they are designed to the same strength spec as airbus. The one that pulled 5g on recovery was no doubt lighter than Max TO weight or it would have failed. In fact it did deform the structure and it was scrap. The design specs are very conservative. You design to them and no more or you haven't done your job right.
 
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