Zenith, KR2S, or Sonerai: Safety Record Comparison

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JayKoit

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I've got my first project narrowed down to my final four: 1) Zenith 601 HD (the old school design with no wing "issues"), the Zenith 701 with VG's instead of slats (better cruise and glide ratio), the KR2S, and the Sonerai 2 stretch. All of these I would build tri-gear.

i have read things here and there about each aircrafts safety records, including some accident reports, but I'd like to hear feedback from the HBA crew here about which ones you consider the safest, and which ones you would avoid. How would you rank them From safest to most dangerous? I'd like to primarily hear about crashworthiness, fatal accident rates, as well as flight characteristics and stall/spin recovery. Thanks!
 

Aircar

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The KR2 had a fairly poor safety record --there was a special meeting convened one time over here of the Sports Aircraft Association with the special guest being the guy in charge of approving kits and plans for amateur construction (by our pale version of the FAA) -the meeting consisted of a long rollcall of fatal accidents to KRs and the circumstances, pilot qualifications, aircraft time in service and reason for crash --it may be accessible somehow via CASA website or NTSB (Australia) --in any case it seemed that having engine failure in a KR2 was a particularly bad idea.
 

JayKoit

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Thanks aircar, that's pretty close to what I've gathered as well, just from Googling "KR2 safety record". So far it looks like KR2 has the worst fatal accident ratio, and the 701 by far the best -- arguably the best in experimental aviation. But, the 701 overall rate is pretty high, apparently due to its high sink rate, use of alternative engines, and lack of STOL transition training (so I've read).

SVSUsteve, I'd love to hear your thoughts, (and anyone else's too) especially on the Sonerai and KR2S, but also how they compare to the zenith spam can designs...
 

Rick McWilliams

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I have flown the Zenair 701. It has excellent performance but poor handling qualities. The elevator is very sensitive and then loses power at low speeds. The directional stability with feet off the pedeals will result in a slip of about 10 degrees. It requires constant attention in flight. The ailerons have high friction and comparatively high force. The adverse yaw with flaperons active requires attention. The deck angle at stall with slats is impressively high. The short field technique is impressive and requires good technique.

zenair pilots think that regular certified airplanes are easy to fly. I have a very good time flying my easy Zlin through all kinds of aerobatics and even landings. Build a easy to fly Fast RV and be happy.
 

TFF

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You have two fast and two slow. I would bet the fast planes have problems with pilots skill level not high enough for the challenge, mixed in with high performance VW engine reliability. I would like the Sonerai personally. Unless everyone is tiny, the fast planes are just single seaters with room to squeeze another person in.
 

Tiger Tim

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I don't like when people rate ordinary designs as 'safe' or 'dangerous.' If you somehow plotted the safety of every airplane ever on a chart, you'd probably find the vast majority of them all grouped together at the safer end. Besides, as Jack Northrop famously said, "The Piper Cub is the safest airplane ever made, it can just barely kill you." The way I see it, it's the decisions you make building and flying that will be the greatest contributors to how dangerous the plane is.

So, barring designs that have a history of in flight breakups, I think what you really want is reliability. I would go with the airplane with the simplest systems and the one that requires you to be the least test pilotey, and less likely to ever have to test that crashworthiness. Something easy to fly would help too, I guess, but your list seems like a group of fairly tame airplanes to begin with.

Building an airplane is a massive undertaking. When I start I want something that I will love so that it actually gets finished (and without regrets), then I can make sure I have the proficiency to operate it safely.

-Tim
 

TFF

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The safest aircraft around is the Bell JetRanger. The JetRanger is measured in crash per million flight hour; something like 2 crashes per million. Van's is the only kit plane that would have enough sample to be accurate. How do you rate craft like this? Cirrus VK 30 has a 50% crash rate but only 12 planes have ever been completed. The Robinson R66 has a 100% death rate if crashed. Most of those crashes are with people who dont have the skill but the pocket book. We have a guy at the airport just about to finish a fixed gear Glasair. No way is his pilot skills ready for that plane. He has a simple taildragger but he does not fly it well yet. People want high performance with no skill acquired. If you cant do touch and goes in a Beech Bonanza all day long how are you going to fly something hotter?
 

autoreply

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This chart does not tell you anything. How about fatal accidents (not deaths) per 100k hours flown?
Actually it is maybe even more telling as deaths per hour. That number is highly related to the type of airframe, some types of airframe attract dangerous pilots (more money than skill) and due to their mission (fast, long-range) for example are more prone to loss of control in IMC, while the airframe itself might be pretty safe.
 

Topaz

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You have two fast and two slow. I would bet the fast planes have problems with pilots skill level not high enough for the challenge, mixed in with high performance VW engine reliability. I would like the Sonerai personally. Unless everyone is tiny, the fast planes are just single seaters with room to squeeze another person in.
+1. Definitely. The fact is that 1960's-70's era homebuilts are very small, with relatively large engines for their size, and rather relaxed stability compared to Cessnas, Pipers, and the like. They're twitchy, they're hot, and guys were getting into them with little or no transition training of any kind. In the 1980's, you started to see a big emphasis in Sport Aviation and other magazines in talking about the "light controls" of these aircraft and the need for proper transition training. In the 1990's, you started to see kit manufacturers acknowledge reality and the horizontal tails on kitplanes started getting larger. The Lancair Legacy, for example, has something like 10-15% more horizontal tail area than the otherwise nearly identical Lancair 320 from which it was derived.

Look at Autoreply's chart. What's got the highest kill ratio? The hot, fast, high-power birds. People jump into these things from a 150 or 172, without the proper transition training, and then wonder how they end up on the ground in a twisted ball of homebuilt.

What's a wonder is that more guys don't get killed this way.
 

harrisonaero

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What auto's graphic tells us isn't the odds of an aircraft or pilot causing an accident but rather the odds of surviving an accident if one does occur. It's very telling.

There are also similar graphs for stall/approach speed (very non-linear), type of structure (wood vs composite vs aluminum vs steel tube), etc. I know I've seen these in the past- does anyone have them?
 

autoreply

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What auto's graphic tells us isn't the odds of an aircraft or pilot causing an accident but rather the odds of surviving an accident if one does occur. It's very telling.

There are also similar graphs for stall/approach speed (very non-linear), type of structure (wood vs composite vs aluminum vs steel tube), etc. I know I've seen these in the past- does anyone have them?
The most interesting thing is the ones that stand out. Similar stall speeds (by far the largest factor), but very different lethalities. The DA40 vs SR20 comes to mind with afaik 4 times lower lethality record. A good crash cockpit and design for crashes really pays off.
This is the article:
http://documents.zenith.aero/uploads/3/7/5/9/3759177/safety_is_no_accident_zenith_kp1110.pdf
I've seen the stall/lethality rates plotted as well (scaled virtually perfect with kinetic energy at clean stall speed, which afaik was the reason to define LSA as a clean stall speed, not flaps down) and I think they were based on Wanttaja's articles and research.
 

Holden

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When I started designing the Sea-Era with Paul Weston I took the time to read the crash reports for several months. In my opinion safety starts with the ability to LAND ON THE ROAD. :gig: Had to say that because it is true.

When the engine quits, where do you land? Road. If you cannot land there you end up in a field. If it flips over at 40 mph it ain't going to end well with a bubble canopy.

Another issue not shown is that an RV-6 usually has a reliable engine compared to other craft so the airframe record is distorted. A 701 may have a piece of junk engine and it dies 10 times more often. Lumping them all together distorts the cause and effect. 5% for the 701 vs 30% for the RV-6. Why?

701 has big tires and a nose gear with a big tire. This prevents it from flipping over. speeds are slow. RV-6 has small tires, no nose wheel, and it goes right over in the dirt. The 701, if it flips, has side doors. The RV has a bubble canopy. Which do you think makes sense when you are hanging from the seat belt and gas is leaking on you?

When you read the crash reports, you have to read between the lines. Most are NOT pilot error. Most are design error, big time. The pilot usually has little training of how the airplane behaves with a true engine out. Engine out...no place to land. Get slow...spin and die. If they make it to the field then it flips over or the gear digs in. How many cars would "crash" in a field if they were put in a field from the air at 55 mph? Most! Why?

As for any of the choices? None of the above. The 701 is the safest. If you like that ilk, then try the 750 instead. The KR2 or Sonerai 2 is a funeral waiting to happen. Is your life that worthless?

The bottom line is that there is really NO airplane that meets the test of safety, performance, usefullness, and value on the market today that I would buy. That is why I am designing new. It don't exist.

Holden
 
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Aviator168

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In my opinion safety starts with the ability to LAND ON THE ROAD. :gig: Had to say that because it is true.
And fold the wing right after touch down.
BTW. Every trike is able to land on a road.
[video=youtube;E3MlRRM9tpA]http://www.youtube.com/watch?v=E3MlRRM9tpA[/video]
 
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Turd Ferguson

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I've got my first project narrowed down to my final four: 1) Zenith 601 HD (the old school design with no wing "issues"), the Zenith 701 with VG's instead of slats (better cruise and glide ratio), the KR2S, and the Sonerai 2 stretch. All of these I would build tri-gear.
The STOCK CH 701 is the hands down winner based on your criteria. One fatal accident in the US and that's been just recently? However, I wouldn't build one unless I needed it's unique capability, i.e., I wouldn't try to make it go faster cause you'll be disappointed. The 601HD is a good all around airplane which I think would be a good choice for an all metal, all around recreational airplane. With the KR and Sonerai, you'll be doing a lot more experimenting.
 

Pops

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I have a Zenith 601 HD with the good wing. Not finished, needs firewall forward and Canopy. Setting in it, at 6' X 225lbs, the seat is not that comfortable for my size. Dan
 

Holtzy3

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well for a failure that was a pretty good landing. He would have been in a world of trouble if his engine hadn't restarted after the first failure.
 

Brian Clayton

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I think the obvious answer here is to just build all 4, and then fly each one and report back to us. That way each plane will have the same builder and pilot. In fact, if you build all 4 at the same time, then the build quality will not change between models. Seriously, the best thing you can probably do is talk to the highest time owners of each plane you can find and take a realistic appraisal of your personal piloting skills and go from there. Then all you have to do is convince yourself that you made the right decision and take the plunge. Like marrying a really, really ugly woman.
 
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