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RV-12 rivets

N

nowlen

Member
i was considering buying a zodiac 601xl untill 2 had the wings fail inflight ( fatal accidents) . seems the top wing skins pulled loose and bent the wing aft along the fuselage. they stayed attached to the airframe however. the ntsb hasn't come to any conclusions and probably won't because of the experimantal nature of the plane. the plane is built using AVEX blind rivets( considered non structural). they are not dimpled or countersunk. they use a "flush" rivet with a puller that upsets the head to make it a round head shape that's half the height of a standard solid or round head rivet. the wing ribs are about 18"-24" apart with no diagonals or cross bracing and there are only 5 of then outboard of the wing walk area( each wing is about 12' long).

after all that, here is my question: what type of rivets will the rv12 be using and will there be additional ribs in the wings ? i called vans and they wouldn't comment. i think the 12 will be a great plane even if it doesn't have an O-200, sliding canopy, and a tailwheel. bernie
 
RV-12 Wing

nowlen said:
...after all that, here is my question: what type of rivets will the rv12 be using and will there be additional ribs in the wings ? i called vans and they wouldn't comment. i think the 12 will be a great plane even if it doesn't have an O-200, sliding canopy, and a tailwheel. bernie
Click to expand...
I don't know that anybody has seen the new wing for the RV-12. I also don't know if they will demo/test fly it on the POC or wait for the first prototype. I assume you would have an indication of the number of ribs by counting the rivet lines in the existing wing... but I am not sure if there would be any skin joints that weren't on top of a rib. I believe Van's discusses the rivets in the development section for the RV-12 on the company website... but I don't think they are real specific. For the existing wing - see here (zoom in):

http://www.eaa292.org/images/RV12Visit/RV12.02.jpg

Side note to our friends at Van's... It would sure be nice to get an update and photo's of the prototype. I appreciate the Ran's site, as they show a lot of pictures and you get a good feel for construction methods and what I would be getting myself into. I would love to see that for the RV-12. (Still strongly leaning towards the -12) :)

DJ
 
Phyrcooler said:
Side note to our friends at Van's... It would sure be nice to get an update and photo's of the prototype. I appreciate the Ran's site, as they show a lot of pictures and you get a good feel for construction methods and what I would be getting myself into. I would love to see that for the RV-12. (Still strongly leaning towards the -12) :)

DJ
Click to expand...


Yeah, what he said :) :D

Maybe an update at Homecoming??
 
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Do your own research

nowlen said:
i was considering buying a zodiac 601xl untill 2 had the wings fail inflight ( fatal accidents) . seems the top wing skins pulled loose and bent the wing aft along the fuselage.
Click to expand...

One reference is to N105RH, full narrative here: http://www.ntsb.gov/ntsb/brief2.asp?ev_id=20060217X00209&ntsbno=LAX06LA105&akey=1

According to someone I spoke with who claimed to have personally examined the wreckage (in all fairness I can only take his word that this is true), this was a result of the rear spar attachment bolts not being reinstalled. Evidently the aircraft can be flown without those bolts - until the flaps are deployed which imparts a twisting of the wing should the rear spar bolts not be present.

Neither the wing attachment point hole nor the fuselage attachment point hole where the rear spar bolts go through showed any deformation in the wreckage - hence it is thought that the bolts were not present. Had they been present, the metal would have been deformed as they pulled out. The NTSB narrative mentions only 12 bolts, which seems to corraborate this. I don't know anything about top wing skins having any trouble.


The second reference is N10028, preliminary report here: http://www.ntsb.gov/ntsb/brief.asp?ev_id=20070509X00539&key=1

Convective activity played a role here. Noteworthy are weather reports at the time of the accident: "Weather reported at Hemphill County Airport at 1230 was wind from 020 degrees at 4 knots, visibility 10 statute miles, scattered clouds 1,200 feet, broken clouds 2,000 feet, overcast clouds 2,600 feet, temperature 63 degrees, dew point 61 degrees, and a barometric pressure setting of 29.94 inches of Mercury.

Weather reported at 1245 was wind from 100 degrees at 7 knots, visibility 3 statute miles, heavy rain, scattered clouds 500 feet, broken clouds 2,000 feet, overcast clouds 2,900 feet, temperature 61 degrees, dew point 61 degrees, a barometric pressure setting of 29.94 inches of Mercury, and lightning southwest of the airport.

Weather reported at 1305, was wind from 360 degrees at 5 knots, visibility 2 statute miles, heavy rain, scattered clouds 200 feet, broken clouds 800 feet, overcast clouds 2,000 feet, temperature 59 degrees, dew point 59 degrees, and a barometric pressure setting of 29.93 inches of Mercury."

Comments welcome.

PatrickW
 
ntsb reports/sodiac 601xl

thanks for that info. those ntsb reports are 2 of the 4 accidents. the other 2 were in ca. a 701 and 601. what you say makes sense. you'd think the ntsb and the manufacture (zenith) would put out that information. i'll just have to wait till the rv 12 gets online. it will probably be a better airplane than the zodiac even thought i don't really like the engine they are using. now you get to worry about a coolent leak in additin to an oil leak. thanks again for the info bernie
 
601XL wings

Hi bernie,
I have been following the 601XL accidents for some time. From what I can gather, the last 601 accident with airframe braking up is pilot error. I was talking to one guy at Oshkosh, who lives in the area. He stated that the pilot entered IFR conditions without wearing a seatbelt!

For the other accident, I have a friend in CA who stated that the pilot was ejected out the aircraft in the air. Extreme negative g loads seem to be the cause of this, as I cannot see how else anyone can be ejected out of an aircraft.

I do not wee what rivets have to do with it. The rivet used is also used on FAA certified aircraft. I just decided to purchase a 601XL QBK, so I did a lot of research on this, and as an engineer, I am 100% confident about the structure and rivets of the XL.



nowlen said:
i was considering buying a zodiac 601xl untill 2 had the wings fail inflight ( fatal accidents) . seems the top wing skins pulled loose and bent the wing aft along the fuselage. they stayed attached to the airframe however. the ntsb hasn't come to any conclusions and probably won't because of the experimantal nature of the plane. the plane is built using AVEX blind rivets( considered non structural). they are not dimpled or countersunk. they use a "flush" rivet with a puller that upsets the head to make it a round head shape that's half the height of a standard solid or round head rivet. the wing ribs are about 18"-24" apart with no diagonals or cross bracing and there are only 5 of then outboard of the wing walk area( each wing is about 12' long).

after all that, here is my question: what type of rivets will the rv12 be using and will there be additional ribs in the wings ? i called vans and they wouldn't comment. i think the 12 will be a great plane even if it doesn't have an O-200, sliding canopy, and a tailwheel. bernie
Click to expand...
 
601xl

have you noticed that the 601xl has 1/2 of the # of wing ribs outboard of the wing walk as the the rv-12 and rans s-19 ? they also use .025 6061 al instead of 2024. that should tell us something. bernie 530-275-3103
 
nowlen said:
have you noticed that the 601xl has 1/2 of the # of wing ribs outboard of the wing walk as the the rv-12 and rans s-19 ? they also use .025 6061 al instead of 2024. that should tell us something. bernie 530-275-3103
Click to expand...

It tells us that the RV-12 and the S-19 require that more attention be paid to preventing corrosion.

I don't know about the impact of the number of ribs outside of the wing walk. Sounds reasonable that "more is better" up to a point. Maybe double the number would be better? Or triple the number? Better yet, how about 4 times the number...?

Does anyone here know where the point of diminishing returns on the strength to weight curve is? Given the large number of examples that are actually flying I'd say that it's on the safe side. If it wasn't, the FAA would ground them faster than you can believe.

Again, do your own research...

Patrick
 
nowlen said:
have you noticed that the 601xl has 1/2 of the # of wing ribs outboard of the wing walk as the the rv-12 and rans s-19 ? they also use .025 6061 al instead of 2024. that should tell us something. bernie 530-275-3103
Click to expand...
It tells us that Chris Heintz knows that for thin sheet metal structure the failure mode of many parts is by buckling. The load that a part will take before buckling depends on the thickness of the metal and its elastic modulus, not the yield strength. All aluminum alloys have the same elastic modulus, so a thin sheet metal structure made from 6061 will have the same strength as one made from 2024, but the one made from 6061 will be cheaper and more resistant to corrosion.
 
6061 is widely used for construction of aircraft structures, such as wings and fuselages, more commonly in homebuilt aircraft than commercial or military aircraft. [2]

6061 is used for yacht construction, including small utility boats. [3]

6061 is commonly used in the construction of Bicycle Frames and components. The Cycling industry also uses 7005 and 7075 aluminium alloys.

2024 is widely used for construction of aircraft structures, such as wings and fuselages. [2] The superior metal fatigue resistance of 2024 makes it popular for aircraft structures which are under tension, such as the bottom of wings. [3]
 
Stronger...

Kevin Horton said:
It tells us that Chris Heintz knows that for thin sheet metal structure the failure mode of many parts is by buckling. The load that a part will take before buckling depends on the thickness of the metal and its elastic modulus, not the yield strength. All aluminum alloys have the same elastic modulus, so a thin sheet metal structure made from 6061 will have the same strength as one made from 2024, but the one made from 6061 will be cheaper and more resistant to corrosion.
Click to expand...
It could also say he is "value conscious" (aka cheap).... :)

For almost all other physical properties, and just about every other failure mode, 2024-T3 is quite measurably better than 6061-T6

Compare numbers...

http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA2024T3

http://asm.matweb.com/search/SpecificMaterial.asp?bassnum=MA6061T6

gil in Tucson
 
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