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Thread: Feedback Needed - Homebuilt Aircraft Cruise Speeds

  1. #21

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    Ron, the number of Airdrome Nieuports, both 11 and 17, are barely in double digits, and true replicas are in the single digits. The vast majority of them are Circa (Graham Lee).

    The differences between Circa and Airdrome aren't meaningful when it comes to surviveability; they're both aluminum tube-and-gusset with pop rivets.

    I suspect true statistics on wrecks vs injury in inexpensive, light aircraft like these is impossible. Liability without hull insurance is the rule. When I flipped my plane, replacing two spars, the prop, crankshaft, gear leg, brakes, wheels, recover and paint the two wings cost less than 1,500 bucks. It won't show up in a database, as it wasn't reported to the FAA or NTSB (though I did file a NASA report).

    Talking within the community, incidents like mine aren't as uncommon as I thought they were. If it doesn't happen in front of the FAA, the cops, or a reporter, it just didn't happen.

    If I had the big money put into an RV, though, I'd probably report it properly and file a claim, as those kinds of repairs would be high. And the stats would be more robust.
    Last edited by Frank Giger; 12-08-2017 at 10:36 AM.
    The opinions and statements of this poster are largely based on facts and portray a possible version of the actual events.

  2. #22
    rwanttaja's Avatar
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    Quote Originally Posted by Frank Giger View Post
    I suspect true statistics on wrecks vs injury in inexpensive, light aircraft like these is impossible. Liability without hull insurance is the rule. When I flipped my plane, replacing two spars, the prop, crankshaft, gear leg, brakes, wheels, recover and paint the two wings cost less than 1,500 bucks. It won't show up in a database, as it wasn't reported to the FAA or NTSB (though I did file a NASA report).

    Talking within the community, incidents like mine aren't as uncommon as I thought they were. If it doesn't happen in front of the FAA, the cops, or a reporter, it just didn't happen.
    Or with serious injuries or death, of course.

    Otherwise, very true, and not just on the low-buck airplanes. I had previously mentioned a BD-4 accident that occurred at an EAA picnic on an airpark. Chapter members got the pieces stuffed into a hangar before the cops showed up.

    Another case involved a taxi accident of another BD-4. The owner argued this didn't qualify as an aviation accident because the airplane hadn't yet been given an airworthiness certificate. Plus it didn't have wings on.

    Ron Wanttaja

  3. #23
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    Quote Originally Posted by Frank Giger View Post
    Talking within the community, incidents like mine aren't as uncommon as I thought they were. If it doesn't happen in front of the FAA, the cops, or a reporter, it just didn't happen.
    Quote Originally Posted by rwanttaja View Post
    Otherwise, very true, and not just on the low-buck airplanes. I had previously mentioned a BD-4 accident that occurred at an EAA picnic on an airpark. Chapter members got the pieces stuffed into a hangar before the cops showed up.
    Yeah, I've seen more than a few wrecks being tucked out of sight as soon as possible. But with cellphones being ubiquitous nowadays people are just programmed to dial 911 at the slightest provocation, so I suspect even minor accidents will be more likely to be reported.

    Of course I was just unlucky, making my forced landing earlier this fall within sight of a major interstate. They demanded I remove the wreckage immediately just so they'd stop getting 911 calls.

  4. #24

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    Quote Originally Posted by Dana View Post
    Yeah, I've seen more than a few wrecks being tucked out of sight as soon as possible. But with cellphones being ubiquitous nowadays people are just programmed to dial 911 at the slightest provocation, so I suspect even minor accidents will be more likely to be reported.

    Of course I was just unlucky, making my forced landing earlier this fall within sight of a major interstate. They demanded I remove the wreckage immediately just so they'd stop getting 911 calls.
    "The Guys" at small GA airfields are a little more autonomous (anti authority?) and value privacy more than your typical Facebook poster. I've known of a few bent airplanes that were loaded onto an airplane gurney, tucked away into a hangar, and healed themselves without any "help" from persons outside the airport community.

  5. #25

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    Quote Originally Posted by rwanttaja View Post
    Or with serious injuries or death, of course.

    Otherwise, very true, and not just on the low-buck airplanes. I had previously mentioned a BD-4 accident that occurred at an EAA picnic on an airpark. Chapter members got the pieces stuffed into a hangar before the cops showed up.

    Another case involved a taxi accident of another BD-4. The owner argued this didn't qualify as an aviation accident because the airplane hadn't yet been given an airworthiness certificate. Plus it didn't have wings on.
    A friend of mine had the engine quit on a T-cart when he was about to enter downwind in the pattern. Could not quite make the runway and the plane flipped over in a field. The locals were there before the dirt settled, one of which was John Swick. After a brief discussion, JS said "the fewer people that find out the better" so they toted the plane to an empty hangar and and had the sight cleaned up in no time. I like that kind of thinking.

    I know of a no wings installed accident and the feds said, nope, no intent to fly so it was essentially a go-kart accident.

  6. #26

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    Ron, the KR2 is significantly slower than the (still) published 180 mph. And I believe that early claim was for top speed, not cruise. Almost no KR's have retract gear anymore (and haven't for many years --- bad original design), and even with the later larger-bore VW engines, cruise is in the 140-150 mph range. Top speed 165-170. The few flyers who have put a Corvair engine in their KR are getting up in that 180-195 area. And loving it!

  7. #27
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    Quote Originally Posted by rwanttaja View Post
    I tend to leave off types with fewer accidents, since it's tough to draw conclusions over only a couple of cases. This is why a number of types aren't included.

    On a similar note, I have 17 Nieuport accidents in my database...but no reliable way to tell which are CIRCA/Graham Lee, Aerodrome, Redfern, etc. types. Eleven had VW engines, so I expect they're CIRCA. But, again, not enough accidents to draw conclusions.

    I didn't include the RV-12 as it's tough to differentiate the EAB from the ELSAs in the NTSB reports and FAA registry, and my focus is EABs. I attempt to track them, but generally don't include them on any released analyses.



    My 1998-2016 database is showing six Tango accidents in the US, but only one fatal (FTW01LA032, continued VFR into IFR conditions, with icing thrown in). I'm suspecting this is an aircraft nomenclature issue (e.g., aircraft model something that doesn't parse as "Tango"). I'd be obliged for more information, to help tune my database.

    Ron Wanttaja
    The accident occurred on July 1st, 1997, so I guess it's out of your range.

    Here's the link anyway...

    https://app.ntsb.gov/pdfgenerator/Re...mmary&IType=LA

    Looks like the NTSB has cleaned up it's database a bit and the older reports are not as detailed as they once were. The report I saw a bunch of years ago went into a bit more detail about the pilot and his "unwise" flying habits. It's only touched on in the link I provided, but I believe that the folks investigating the accident determined that he had done a complete 360 from the top of the trees to impact.
    Someday I'll come up with something profound to put here.

  8. #28

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    Hi Ron,
    Always appreciate your analysis of aircraft accidents. It informs the entire community.
    Instead of cruise speed as differentiator, why not use stall speed since most accidents occur during takeoff and landing.

    Quote Originally Posted by rwanttaja View Post
    My definition of Fatality Rate is the number of accidents with at least one fatality, vs. the total number of accidents.



    Certainly, but unfortunately, that's difficult data to extract. Plus, of course, accidents are random events...a fatality might depend on whether the passenger is leaning over to tie his shoe, etc.

    I certainly understand I can't *prove* the theory that wing position affects survivability. I'm attempting to find some correlation by using thousands of aircraft in each configuration. The homebuilt accident record provides about 3800 accidents over the 19-year period my database runs.

    Obviously, the speed at impact is a very big driver...energy increases by the square of the impact velocity. I'm hoping to use cruise speed to differentiate...but, of course, few airplanes actually CRASH at cruise speed. I'm using cruise speed just to indicate the approximate operating range of the aircraft. An RV-6 approaches faster than the cruise speed of Frank's Nieuport, but by using cruise speed as the factor the difference in capability is acknowledged.

    One drawback is that there ARE no quantities of high-performance high-wing homebuilts. There are a few Aerocomps, even fewer Stallions. So it's hard to get data in the higher-performance regime.

    There is some correlation in the production-aircraft world. The Cessna 172 has a fatality rate of 12.%, while the PA-28 (through the -181) it's 19%. The Bonanza and the Cirrus both have rates in the low '30s, while the Cessna 210 is 20%. However, the 210 has a lot of landing-gear-related and fuel starvation accidents, which usually aren't fatal.

    Ron Wanttaja

  9. #29
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    Quote Originally Posted by SamP View Post
    Hi Ron,
    Always appreciate your analysis of aircraft accidents. It informs the entire community.
    Instead of cruise speed as differentiator, why not use stall speed since most accidents occur during takeoff and landing.
    It certainly can be argued either way. However, when I'm looking at fatality rates, I prefer cruise speed for a couple of reasons.

    1. It's a better indicator of a high-performance aircraft. If a plane "gets away" from the pilot, a higher cruise speed indicates it would accelerate faster and to a higher speed.

    2. There's the difference between dirty and clean stall speeds... which would I use? Dirty stall speed is applicable to landing accidents, while clean stall speeds are more related to stalls in other phases. Note this graphic from an upcoming KITPLANES article...it's tough to decide which parameter to compare. Since most stalls of operational homebuilt occur on takeoff and initial climb, clean stall might be better. But the base/final stall/spin is such an ingrained aspect of our lives, it's hard to fight the dirty-stall idea.

    Discussing it, though, makes me wonder if wing loading might be a better factor than cruise or stall speed. Probably less prone to marketing distortion.

    Ron Wanttaja
    Last edited by rwanttaja; 04-20-2018 at 04:34 PM.

  10. #30

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    Quote Originally Posted by rwanttaja View Post
    Note this graphic from an upcoming KITPLANES article...it's tough to decide which parameter to compare.

    Discussing it, though, makes me wonder if wing loading might be a better factor than cruise or stall speed. Probably less prone to marketing distortion.

    Ron Wanttaja
    The fatal accident data for certificated airplanes is very similar in where the accidents occurred. Many, many more are on takeoff and go-around.

    wing loading might be good. ASTM is looking at control forces, configuration changes (and resulting forces), etc.

    I look forward to your upcoming article!

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