Dead Aurora....
03-11-2008 | 01:58 PM
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From: Austin,
TX
Dead Aurora....
The Aurora died a horrible death a few minutes ago. I was out practicing and did a snap roll. The wing failed and it went in from about 200' and landing on a big-*****ed limestone rock. It looks like the engine survived, although it pulled one header bolt out. I'll have to drill and tap that. The radio gear looks ok, but I just walked in and haven't checked it.
Looking at the wing, it seems as if the skins weren't bonded very well to the foam. I can't tell what was used, but it looks kinda like sorghum. I guess after all these years it let go.
I know every plane has an expiration date, but it sure woulda been nice if was further out... Pics to follow after I charge the camera. At least we can all enjoy a good carnage shot.
Tim
Looking at the wing, it seems as if the skins weren't bonded very well to the foam. I can't tell what was used, but it looks kinda like sorghum. I guess after all these years it let go.
I know every plane has an expiration date, but it sure woulda been nice if was further out... Pics to follow after I charge the camera. At least we can all enjoy a good carnage shot.
Tim
03-11-2008 | 04:35 PM
#3
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RE: Dead Aurora....
It will be interesting to see where the wing fractured. It should be very hard for it to fail in the center section because they usually fail just to the outside of the center section fiberglass. This is sometimes caused by not protecting the balsa skin when sanding the center section fiberglass.
03-11-2008 | 05:31 PM
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From: Austin,
TX
RE: Dead Aurora....
That's exactly where it failed - about 1/8" outboard of the center section glass. As I said above, there was a very poor bond between the sheeting and the core in large areas. It served the original owner well for a lot of flying, so I can only surmise that sitting for the past 13-14 years had a detrimental effect on the bond.
03-11-2008 | 06:56 PM
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From: Austin,
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RE: Dead Aurora....
ORIGINAL: LS171Malibu
Man, that is horrible... I was really hoping to see it at the Ft. Worth contest. Sorry for your loss. [&o]
Man, that is horrible... I was really hoping to see it at the Ft. Worth contest. Sorry for your loss. [&o]
I'm still coming! I'm motivated now to go on an extreme building binge and see if I can get my Curare ready for Ft Worth. Don' know if I'll get it done in time, and even if I do I won't have any practice on it. But, if I can get it in the air I'll still bring it and at least bore some holes in the sky.
03-11-2008 | 07:33 PM
#7
RE: Dead Aurora....
Tim,
Sorry to here the Aurora went in....
I had a Tipo that did the same thing. The wing skin came loose from the foam core. Southern Sorghum was used. One snap is all it took. The Tipo was some what controlled to the ground where it landed into soft grass/hay field that wasn't cut yet. After further investigation.... and going off the other wing panel and stab (which was not touched) it would of appeared the Sorghum expired first.... then the plane followed. I cut one cut one half off the stab off the fuse after I was able to literally pull the skin of the wing with my hands. Sure enough....same goes for the stab. I was able to remove the stab skin with very little effort. From that day on.... I use nothing but epoxy or the newest trend, Gorilla Glue to do skins. Once again... sorry for your loss Tim.
Mark
Sorry to here the Aurora went in....
I had a Tipo that did the same thing. The wing skin came loose from the foam core. Southern Sorghum was used. One snap is all it took. The Tipo was some what controlled to the ground where it landed into soft grass/hay field that wasn't cut yet. After further investigation.... and going off the other wing panel and stab (which was not touched) it would of appeared the Sorghum expired first.... then the plane followed. I cut one cut one half off the stab off the fuse after I was able to literally pull the skin of the wing with my hands. Sure enough....same goes for the stab. I was able to remove the stab skin with very little effort. From that day on.... I use nothing but epoxy or the newest trend, Gorilla Glue to do skins. Once again... sorry for your loss Tim.Mark
03-11-2008 | 08:40 PM
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RE: Dead Aurora....
Would there be any way to check for this flaw or weakness prior to flight or failure? Just curious as I have a couple of these old planes. The T2A MKII I have flown at least 15 times but have not done any hard maneuvering. The Atlanta is undergoing an engine mount to rudder refurbishing right now. And she will fly soon(quiet, navav2002
). Just curious if there is a way to inspect for a potential problem.
). Just curious if there is a way to inspect for a potential problem.
03-11-2008 | 08:54 PM
#11
RE: Dead Aurora....
The only way I can see testing for this is taking the wing and putting a little pressure on the top of the skin and see if there is any movement or flex in the skin itself. If it has pulled away from the foam itself.... you will feel the skin move a little with pressure. I have a wing I'll dig out and shoot some pictures of. This very exact "thing" is going on. Give me a day or to to get it though.
03-11-2008 | 11:54 PM
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From: Monroe, WA
RE: Dead Aurora....
Just as a data point, a few years ago I cut into a foam flying boat hull I'd built in the early 70's. Sourghum was used to attach 1/16" balsa that was then glassed. It had been flown a number of times before being set aside.
What I found was that even after all those years the skins were so tightly bonded that I couldn't get them off without ripping the foam apart.
However, I know from the experience of two friends who had the same flying boats without glassing them (one used Monokote and the other stored his unfinished in an unheated detached garage) that Sourghum will eventually lose its grip in the presence of moisture.
None of this is meant to suggest the bond on the Aurora wing didn't fail. The Sourgum may not have been applied properly, it may have been exposed to dampness at some time or something else. All I can gather from my experience is that it doesn't loose its grip with age alone.
FWIW
What I found was that even after all those years the skins were so tightly bonded that I couldn't get them off without ripping the foam apart.
However, I know from the experience of two friends who had the same flying boats without glassing them (one used Monokote and the other stored his unfinished in an unheated detached garage) that Sourghum will eventually lose its grip in the presence of moisture.
None of this is meant to suggest the bond on the Aurora wing didn't fail. The Sourgum may not have been applied properly, it may have been exposed to dampness at some time or something else. All I can gather from my experience is that it doesn't loose its grip with age alone.
FWIW
03-12-2008 | 02:57 AM
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From: North, UNITED KINGDOM
RE: Dead Aurora....
Very sorry to hear about you loss, if there is any comfort to be had at least you are out flying.
It has been unflyable in England for almost four weeks now.
I have three new F3A models. One unflown, one with two flights, and one with three.
I've got five and a bit weeks to the first comp of the season and I can't get out of the house to trim them out.
33mph winds today!!!!!!!!!!!!
Hope you make it to your comp.
regards piroflip
It has been unflyable in England for almost four weeks now.
I have three new F3A models. One unflown, one with two flights, and one with three.
I've got five and a bit weeks to the first comp of the season and I can't get out of the house to trim them out.
33mph winds today!!!!!!!!!!!!
Hope you make it to your comp.
regards piroflip
03-12-2008 | 01:57 PM
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From: Maynardville, TN
RE: Dead Aurora....
Sorry to hear that a good one went down. This kinda' makes me wonder about those high dollar E-bay kits with pre-skinned foam core wings. I know that some of the MK kits had built up wings, which wouldn't be affected, but I never really considered failure of the glues used in the foam wing kits going bad but after all these years it is something to consider. Makes me feel a little better about not spending the big bucks in the bidding wars. Scratch building is beginning to look a lot more attractive.
03-12-2008 | 02:34 PM
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From: Euharlee,
GA
RE: Dead Aurora....
Yeah..Given this event..I think I'm going to get a new set of cores and re-do the wings for my used Atlanta...It had been converted to a t'dragger and I was going to have to re-work all that anyway...I think I'll just be better off starting from scratch with a new set of wings...I went down and took a look at them last night after reading this post...Although I feel they are probably solid...I'm not overly impressed with the factory sheeting job to begin with...And I feel they could be lighter...
I'm un-decided on the Horizontal Stab for the moment...
I have a few other "pre-sheeted" sets of wings...Suppose I'll just try and keep my eye on those guys...
I'm un-decided on the Horizontal Stab for the moment...
I have a few other "pre-sheeted" sets of wings...Suppose I'll just try and keep my eye on those guys...
03-12-2008 | 03:08 PM
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From: Maynardville, TN
RE: Dead Aurora....
There has been arguments for years over the virtues of built up wings versus foam core wings. Foams are quicker to build but are generally heavier and tend to have more flex than built up wings. My 30 year old curare was peiced together from a MK wing kit (built up) a glass fuselage that I can't even remember where I got and a foam stab. It flew great but needs a refurb. I wonder if the epoxy's that I used back then have also deteriorated... and if the glass fuselage still has it's strength.
03-12-2008 | 04:21 PM
#19
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RE: Dead Aurora....
ORIGINAL: tony-howard
Just as a data point, a few years ago I cut into a foam flying boat hull I'd built in the early 70's. Sourghum was used to attach 1/16" balsa that was then glassed. It had been flown a number of times before being set aside.
What I found was that even after all those years the skins were so tightly bonded that I couldn't get them off without ripping the foam apart.
However, I know from the experience of two friends who had the same flying boats without glassing them (one used Monokote and the other stored his unfinished in an unheated detached garage) that Sourghum will eventually lose its grip in the presence of moisture.
None of this is meant to suggest the bond on the Aurora wing didn't fail. The Sourgum may not have been applied properly, it may have been exposed to dampness at some time or something else. All I can gather from my experience is that it doesn't loose its grip with age alone.
FWIW
Just as a data point, a few years ago I cut into a foam flying boat hull I'd built in the early 70's. Sourghum was used to attach 1/16" balsa that was then glassed. It had been flown a number of times before being set aside.
What I found was that even after all those years the skins were so tightly bonded that I couldn't get them off without ripping the foam apart.
However, I know from the experience of two friends who had the same flying boats without glassing them (one used Monokote and the other stored his unfinished in an unheated detached garage) that Sourghum will eventually lose its grip in the presence of moisture.
None of this is meant to suggest the bond on the Aurora wing didn't fail. The Sourgum may not have been applied properly, it may have been exposed to dampness at some time or something else. All I can gather from my experience is that it doesn't loose its grip with age alone.
FWIW
I’ve had very good long term results with Sourghum too. I use it on wings that I’m going to MonoKote and for painted wings I use epoxy in a press. One that is not good is 3M 77 foam contact spray because it melts in hot sun light.
03-12-2008 | 04:56 PM
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From: Austin,
TX
RE: Dead Aurora....
I really appreciate the sympathy from y'all! Hopefully this thread will save somebody else's historic bird.
From reading all the responses, it seems as everyone has had differing results with different adhesives. I'm beginning to think that it comes down to the quality of the original bond and the conditions that it's been stored in. Having been in San Antonio for its life, it's hard to tell what kind of conditions the wing went through. It's hotter than hell in the summer, cold in the winter (relatively speaking for some of you guys!), and humid as all get-out. I used to even use 3M 77 on all of my high performance slope planes and never had a failure.
I suppose that if/when I buy another used classic, that I'll go ahead and build a set of wings for it that I know are adhered well. I know there are a lot of good builders out there, but I won't chance trashing a classic again. This isn't to bash the guy that built mine - he flew it at the national level for several years before it was retired and never had a problem. It's not the $$ part that hurts, although that does suck. The fact that I just lost one of, or possibly the last, remaining PA2 is the worst.
NAVAV2002 - time to get busy on your plug so I can get a fuse from ya!!!
Tim
From reading all the responses, it seems as everyone has had differing results with different adhesives. I'm beginning to think that it comes down to the quality of the original bond and the conditions that it's been stored in. Having been in San Antonio for its life, it's hard to tell what kind of conditions the wing went through. It's hotter than hell in the summer, cold in the winter (relatively speaking for some of you guys!), and humid as all get-out. I used to even use 3M 77 on all of my high performance slope planes and never had a failure.
I suppose that if/when I buy another used classic, that I'll go ahead and build a set of wings for it that I know are adhered well. I know there are a lot of good builders out there, but I won't chance trashing a classic again. This isn't to bash the guy that built mine - he flew it at the national level for several years before it was retired and never had a problem. It's not the $$ part that hurts, although that does suck. The fact that I just lost one of, or possibly the last, remaining PA2 is the worst.
NAVAV2002 - time to get busy on your plug so I can get a fuse from ya!!!
Tim
03-12-2008 | 07:17 PM
#21
RE: Dead Aurora....
ORIGINAL: Fxrs_tim
I really appreciate the sympathy from y'all! Hopefully this thread will save somebody else's historic bird.
From reading all the responses, it seems as everyone has had differing results with different adhesives. I'm beginning to think that it comes down to the quality of the original bond and the conditions that it's been stored in. Having been in San Antonio for its life, it's hard to tell what kind of conditions the wing went through. It's hotter than hell in the summer, cold in the winter (relatively speaking for some of you guys!), and humid as all get-out. I used to even use 3M 77 on all of my high performance slope planes and never had a failure.
I suppose that if/when I buy another used classic, that I'll go ahead and build a set of wings for it that I know are adhered well. I know there are a lot of good builders out there, but I won't chance trashing a classic again. This isn't to bash the guy that built mine - he flew it at the national level for several years before it was retired and never had a problem. It's not the $$ part that hurts, although that does suck. The fact that I just lost one of, or possibly the last, remaining PA2 is the worst.
NAVAV2002 - time to get busy on your plug so I can get a fuse from ya!!!
Tim
I really appreciate the sympathy from y'all! Hopefully this thread will save somebody else's historic bird.
From reading all the responses, it seems as everyone has had differing results with different adhesives. I'm beginning to think that it comes down to the quality of the original bond and the conditions that it's been stored in. Having been in San Antonio for its life, it's hard to tell what kind of conditions the wing went through. It's hotter than hell in the summer, cold in the winter (relatively speaking for some of you guys!), and humid as all get-out. I used to even use 3M 77 on all of my high performance slope planes and never had a failure.
I suppose that if/when I buy another used classic, that I'll go ahead and build a set of wings for it that I know are adhered well. I know there are a lot of good builders out there, but I won't chance trashing a classic again. This isn't to bash the guy that built mine - he flew it at the national level for several years before it was retired and never had a problem. It's not the $$ part that hurts, although that does suck. The fact that I just lost one of, or possibly the last, remaining PA2 is the worst.
NAVAV2002 - time to get busy on your plug so I can get a fuse from ya!!!
Tim
03-12-2008 | 09:44 PM
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From: Euharlee,
GA
RE: Dead Aurora....
ORIGINAL: Fxrs_tim
<snip>
NAVAV2002 - time to get busy on your plug so I can get a fuse from ya!!!
Tim <snip>
<snip>
NAVAV2002 - time to get busy on your plug so I can get a fuse from ya!!!
Tim <snip>
I was sorta toying with the idea of putting the SkyMaster in front of the Aurora...But I don't think I'm gonna do that...I want an Aurora pretty darn bad myself...
I may try and work them sorta in conjunction with each other but with Aurora as my main priority...After Atlanta of course...
Have Fun...
Chuck
