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#11
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On Wed, 03 Sep 2003 13:01:42 GMT, Jay Honeck wrote:
Reason for asking: A long discussion with some pilots who were staying at the inn, who contend that they just won't last. Using as an example the fiberglass wing tips and cowlings that always crack, flake, and crumble after 15 years, requiring costly (and usually unsuccessful) repairs, these pilots are convinced that the composite material in Cirrus will eventually behave in much the same way. And once your fuselage parts start to crack, flake, and delaminate, the planes will become essentially large paper-weights. Our flying club in Houston had an old Arrow 1. The cowling was still in good (but not perfect) condition. The cowling is in a hostile place - baking hot engine. The structure of the fibreglass was sound. It had been around since the 1960s. As others have noted, plenty of old fibreglass gliders are still beautiful today. Take care of the paintwork and the composite Cirrus will last too. You need to take care of the paintwork on a metal plane too (or they corrode, especially where I live, right next to the sea). You can't really compare Piper's crappy cowlings from the 60s to the processes used to make the Cirrus/Lancair/Diamond aircraft today. -- Dylan Smith, Castletown, Isle of Man Flying: http://www.dylansmith.net Frontier Elite Universe: http://www.alioth.net "Maintain thine airspeed, lest the ground come up and smite thee" |
#12
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Jay Honeck wrote: So what's the group-think here? Will we by flying used Cirrus' in 20 years? I still see a fair number of antique Corvettes on the road. George Patterson A friend will help you move. A really good friend will help you move the body. |
#13
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Composite gliders have been around for over 40 years with an excellent
record for structural integrity. My Glasflugel H301 Libelle glider, N301BW, will be 40 years old in 2004. Made of plain 'ol E glass and epoxy. Closing in on 3000 hours of flying time, still looks and performs great. Very few AD's, all on the metal parts. I have owned and flown old wood, old metal, and old glass. I have had more problems with the metal than the wood and glass put together. Corrosion and fatigue. Probably because people are more likely to take care of wood and plastic and to neglect metal. Fabric covered aluminum wings are probably the worst for this. Often left sitting out for years with moisture collecting in wing, not to mention rodent urine, etc. Seen aircoupe spars that were little more than aluminum oxide powder. One thing about old glass: Old fiberglass aircraft were significantly overbuilt to get some rigidity out of the very flexible fiberglass. Hence, my glider has a 9.5 g wing just to make the wing stiff enough to keep both tips from drooping to the ground when it's not flying. Carbon is stiff enough that you can build a stiff structure that is still pretty weak. Composite materials tech and fabricating methods are advancing at a high rate. Eventually, new metal airplanes are going to get rare (says the guy who just bought a bunch of steel tubes, rags, and sticks with a late 40's Continental to drag it through the air). |
#14
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In a previous article, Foster said:
Paul Tomblin wrote: Looking at the 5 Pipers on our flight line (http://www.rochesterflyingclub.com/f...equipment.html), (and the four aircraft that we've sold in the time I've belonged to the club) I'd have to say that Piper wingtips, wheel fairings and cowls are made with possibly the worst grade of fiberglass ever made. That's why they're so cheap to replace. ;-) No, that's why we've got a pair of LoPresti Zip Tips waiting for us when we take the Dakota to Goderich to get repainted this fall. We're not wasting another dime of Piper crap fiberglass. -- Paul Tomblin , not speaking for anybody It could have been raining flaming bulldozers, and those idiots would have been standing out there smoking, going 'hey, look at that John Deere burn!' -- Texan AMD security guard |
#15
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Paul Tomblin wrote: Looking at the 5 Pipers on our flight line (http://www.rochesterflyingclub.com/f...equipment.html), (and the four aircraft that we've sold in the time I've belonged to the club) I'd have to say that Piper wingtips, wheel fairings and cowls are made with possibly the worst grade of fiberglass ever made. That's why they're so cheap to replace. ;-) |
#16
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Jay,
The composites used on Cirrus are not anything close to the fiberglass material you describe. The better comparison is to look at composite sailplanes that are twenty and thirty years old and have no problems. The UV issue was dealt with 20 years ago as well. Because of the FAA's extremely conservative certification procedures for composites, the structures are far, far stronger than metal airplanes, which is why they also weigh as much. The FAA certification procedures took away the weight advantage of composites, but what it did was give us airplanes that are evern more overbuilt than the Grumman Ironworks figthers of WWII. Warmest regards, Rick "Jay Honeck" wrote in message news:WCl5b.344377$uu5.68896@sccrnsc04... Okay, so Cirrus is cooking along at 60 aircraft per month. They're selling everything they can build, and people who have bought them are ecstatic. Fast forward to the year 2018. What's going to be happening to these composite beauties? Reason for asking: A long discussion with some pilots who were staying at the inn, who contend that they just won't last. Using as an example the fiberglass wing tips and cowlings that always crack, flake, and crumble after 15 years, requiring costly (and usually unsuccessful) repairs, these pilots are convinced that the composite material in Cirrus will eventually behave in much the same way. And once your fuselage parts start to crack, flake, and delaminate, the planes will become essentially large paper-weights. So what's the group-think here? Will we by flying used Cirrus' in 20 years? Or will they all be scrap by then? |
#17
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#18
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A good place to start looking at longevity is the Slingsby T-3. It is
probably the one aircraft out there that is really accumulating hours at a rate with reliable and exacting maintenance standards, that will give you a good idea. So far it has been a big bust in the training program for the USAF. It is the only aircraft that I have ever seen that has a structural temperature limitation. If the structure is over a certain surface temp, it is prohibited from flight due to structural degredation at the elevated temp. With the big engine, it is extremely temp sensitive under the cowling and has what appears to be massive vapor locking problems despite using multiple fuel pumps. The problems with the a/c power and structure have become so problematical, that the USAF grounded the fleet and will probably destroy the a/c rather than let them get into civilian hands. I know it's only one aircraft, but the design is certified at a minimum to FAR 23 standards. What is interesting, is the a/c that are built to the same TC, and using the smaller engines so far don't have the same problems. Even those that are in military training programs outside the USAF don't have the same fuel and structure problems that I've been able to find. Craig C. |
#19
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"Craig" wrote in message om... A good place to start looking at longevity is the Slingsby T-3. It is probably the one aircraft out there that is really accumulating hours at a rate with reliable and exacting maintenance standards, that will give you a good idea. So far it has been a big bust in the training program for the USAF. It is the only aircraft that I have ever seen that has a structural temperature limitation. If the structure is over a certain surface temp, it is prohibited from flight due to structural degredation at the elevated temp. With the big engine, it is extremely temp sensitive under the cowling and has what appears to be massive vapor locking problems despite using multiple fuel pumps. The problems with the a/c power and structure have become so problematical, that the USAF grounded the fleet and will probably destroy the a/c rather than let them get into civilian hands. I know it's only one aircraft, but the design is certified at a minimum to FAR 23 standards. What is interesting, is the a/c that are built to the same TC, and using the smaller engines so far don't have the same problems. Even those that are in military training programs outside the USAF don't have the same fuel and structure problems that I've been able to find. Craig C. The Slingsby's problems are not composite related. They are engine/fuel system related. Some (all?) of the Diamona's (sp?) have structural temp limitations as well. That's why they paint 'em white. Also, the folks who live in Phoenix or other places that have extreme temperatures often keep 'em hangared. KB |
#20
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Jay Honeck wrote: Okay, so Cirrus is cooking along at 60 aircraft per month. They're selling everything they can build, and people who have bought them are ecstatic. Fast forward to the year 2018. What's going to be happening to these composite beauties? A recent Hot Topic in the local aerobatic community as the recent economic situation has driven several 12-14 year old Extra 300 aircraft onto the market. These birds have 2000 to 2500 hours on them, with a factory limit life of 5000 hrs. These aircraft have been rode hard as flight demonstration team aircraft and appear fine. But, until someone puts the requisite 5000 hrs on one and sends it back to be cut up by the factory for examination it's anybodys guess what the insides look like. Lots of anguish over a recent article in Sport Aerobatics when Bud Davisson had his 30 year old S2A recovered and found lots of weakened/broken glue joints in his wings. Everything was repairable using well established procedures. Nothing like being able to tear off the old cover and get in and have a look around! Try that with your 300k dollar composite airplane! Jerry |
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