Is the Cirrus a Coffin Maker?
Join Date: Aug 1999
Location: uk
Posts: 247
Likes: 0
Received 0 Likes
on
0 Posts
flew one in LA with an FAA safety counsellor as the check out pilot. He had a very sceptical view of the whole Cirrus manual/philosophy/parachute etc
The good news is that the plane is just fine, handles perfectly well, and after about an hour and a half of circuits plus sim engine failures and an IFR flight back to Santa Monica revealed no unpleasant traits at all. Any competent pilot could fly it.
But..........
It only has one engine, so...night or actual IFR ...over populated areas/mountains/sea etc is still as unwise with achute as without.
Also the glass cockpit encourages VFR pilots to fly like pretend IFR pilots, and a lot of customers are seduced by the false security provided by all the shiny technology, rather than stick their head out of the window and use natures horizon.
Almost lastly, my chum went to cirrus "approved" training and asked about their unusual attitude recovery technique. The instructor's response was that Cirrus recommend immediate engagement of the autopilot to correct unusual attitudes!! Cue pilot rolling inverted and engaging autopilot.....
Is this true?
Finally, just get a Twinstar and have done with it, thats how I'd spend my money, I'll take the extra engine over the parachute.
The good news is that the plane is just fine, handles perfectly well, and after about an hour and a half of circuits plus sim engine failures and an IFR flight back to Santa Monica revealed no unpleasant traits at all. Any competent pilot could fly it.
But..........
It only has one engine, so...night or actual IFR ...over populated areas/mountains/sea etc is still as unwise with achute as without.
Also the glass cockpit encourages VFR pilots to fly like pretend IFR pilots, and a lot of customers are seduced by the false security provided by all the shiny technology, rather than stick their head out of the window and use natures horizon.
Almost lastly, my chum went to cirrus "approved" training and asked about their unusual attitude recovery technique. The instructor's response was that Cirrus recommend immediate engagement of the autopilot to correct unusual attitudes!! Cue pilot rolling inverted and engaging autopilot.....
Is this true?
Finally, just get a Twinstar and have done with it, thats how I'd spend my money, I'll take the extra engine over the parachute.
Join Date: Jun 2003
Location: EuroGA.org
Posts: 13,787
Likes: 0
Received 0 Likes
on
0 Posts
The instructor's response was that Cirrus recommend immediate engagement of the autopilot to correct unusual attitudes!! Cue pilot rolling inverted and engaging autopilot.....
Sounds totally unreal. An AP will auto disconnect if the pitch or roll exceed certain values, and it doesn't take much.
Sounds totally unreal. An AP will auto disconnect if the pitch or roll exceed certain values, and it doesn't take much.
Join Date: Aug 2006
Location: Sth Bucks UK
Age: 60
Posts: 927
Likes: 0
Received 0 Likes
on
0 Posts
I met Angelina Jolie at Denham once. The big screen doesn't do her justice! When i cracked a joke and she smiled at me I damn near had an accident there and then!
Join Date: Mar 2000
Location: U.K.
Age: 46
Posts: 3,112
Likes: 0
Received 0 Likes
on
0 Posts
Since the vast majority of accidents are caused by poor decision making, low currency and a lack of training/familiarity with a machine.
The thought of most PPL's I have met (I hasten to add that hopefully the folks I've had a hand in training don't fall into this category) jumping into something like a Cirrus with a minimum of training fills me with dread.
A Cirrus is fast, complex and very different from your average spamcan and requires differences training and maybe even a type rating. I hope we don't wait until there are accidents before this becomes reality.
The thought that you recover from an unusual attitude by switching on the autopilot fills me with horror.
Aztruck, I hope that isn't the case! If so, it shows a startling lack of understanding by the manufacturer of what happens in a cockpit when someone panics after everything goes wrong unexpectedly. That would be the first time I would totally ignore something in a POH!
The thought of most PPL's I have met (I hasten to add that hopefully the folks I've had a hand in training don't fall into this category) jumping into something like a Cirrus with a minimum of training fills me with dread.
A Cirrus is fast, complex and very different from your average spamcan and requires differences training and maybe even a type rating. I hope we don't wait until there are accidents before this becomes reality.
The thought that you recover from an unusual attitude by switching on the autopilot fills me with horror.
Aztruck, I hope that isn't the case! If so, it shows a startling lack of understanding by the manufacturer of what happens in a cockpit when someone panics after everything goes wrong unexpectedly. That would be the first time I would totally ignore something in a POH!
Last edited by Say again s l o w l y; 15th Oct 2006 at 22:59.
Join Date: Jan 2003
Location: Kelowna Wine Country
Posts: 509
Likes: 0
Received 24 Likes
on
10 Posts
I suspect that, if it was not said tongue in cheek, what the chap meant was that if you were to become dis-oriented then you should switch on the autopilot and so allow the aircraft to avoid extreme attitudes.
Having said that there are planes, granted they are bigger ones, in which the auto pilot, or at least the aircraft's computer controls are far more effiecient at returning the aircraft to normal flight after an upset than pilots are. Do not some modern passenger aircraft fly so on the edge of control in some circumstances that it is almost impossible for a pilot to stabilise oscillations without the help of the computers or is that just fiction?
Having said that there are planes, granted they are bigger ones, in which the auto pilot, or at least the aircraft's computer controls are far more effiecient at returning the aircraft to normal flight after an upset than pilots are. Do not some modern passenger aircraft fly so on the edge of control in some circumstances that it is almost impossible for a pilot to stabilise oscillations without the help of the computers or is that just fiction?
Join Date: Mar 2000
Location: U.K.
Age: 46
Posts: 3,112
Likes: 0
Received 0 Likes
on
0 Posts
No, I think you are thinking about the current crop of military fast jets. They rely on computer control (fly by wire) as they are designed to be unstable so that they respond faster.
Snapping into a 9G turn is not something we require our passenger a/c to do. There would be a few G&T's spilt, not to mention the trifling issue of the airframe being ripped apart!
Airbus use fly by wire for other reasons other than purely for stability control. Basically because we pilots like to do things the engineers would rather we didn't and the FBW helps stop that. (i.e flying into the ground and taking no corrective action. If the system can detect it, then it'll do something even if you don't.)
Snapping into a 9G turn is not something we require our passenger a/c to do. There would be a few G&T's spilt, not to mention the trifling issue of the airframe being ripped apart!
Airbus use fly by wire for other reasons other than purely for stability control. Basically because we pilots like to do things the engineers would rather we didn't and the FBW helps stop that. (i.e flying into the ground and taking no corrective action. If the system can detect it, then it'll do something even if you don't.)
I'm a relatively low time PPL and it's been suggested more than once that I should get a Cirrus endorsement as there are a few around here for hire.
I've just last week done an endorsement on Piper Lance - my first six cylinder/six seat aircraft, and that is quite enough to keep me very busy for the forseeable future. I'm current in C172, Warriors, Arrow etc.
My current opinion is that I'm quite busy learning to handle a Lance competently and getting used to planning ahead in a 140/160 knot aircraft. A Cirrus (178 knots?) seems to me to be a bit too much of a handful just now.
Then of course there is the glass cockpit to train on. I note that the Cirrus POH seems to be about three inches thick as well.
My gut feel is as follows: While its a lovely aircraft, I'm a tad concerned about its marketing and who is buying it. I can't see myself in one for at least another year, and to use it propelry I would really like to have an IFR rating.
I'm also concerned about the possibility of "risk shifting" regarding the chute. It is possible that people may be taking more risks on the basis that they believe the BRS will get them out of trouble.
I've just last week done an endorsement on Piper Lance - my first six cylinder/six seat aircraft, and that is quite enough to keep me very busy for the forseeable future. I'm current in C172, Warriors, Arrow etc.
My current opinion is that I'm quite busy learning to handle a Lance competently and getting used to planning ahead in a 140/160 knot aircraft. A Cirrus (178 knots?) seems to me to be a bit too much of a handful just now.
Then of course there is the glass cockpit to train on. I note that the Cirrus POH seems to be about three inches thick as well.
My gut feel is as follows: While its a lovely aircraft, I'm a tad concerned about its marketing and who is buying it. I can't see myself in one for at least another year, and to use it propelry I would really like to have an IFR rating.
I'm also concerned about the possibility of "risk shifting" regarding the chute. It is possible that people may be taking more risks on the basis that they believe the BRS will get them out of trouble.
Join Date: Jun 2003
Location: EuroGA.org
Posts: 13,787
Likes: 0
Received 0 Likes
on
0 Posts
Autopilot operation is indeed mandatory on some bizjets, above a certain altitude, because it flies too close to mach 1 and can become very hard to control (for a human pilot) in pitch.
Speaking as someone who went from a C150/PA28 straight to a TB20, I had about 10 hrs' diff training and that was plenty for VFR flight. Then I did the IMC Rating in it (no point in flying something like that VFR-only); another 20-30hrs. No problem.
Training how to do flight/weather planning for the sort of missions one is going to want to do is something else altogether. There simply isn't anybody in the UK who knows how to do that; VFR or IFR. To this day I have not met an instructor who has even 1/10 of a clue how to do European touring flight planning combined with this level of (limited) mission capability.
I don't think it is flying a nice 150kt plane that is going to get somebody killed. 150kt v. 100kt just means you have to think 1.5 times faster but that's no big deal; it comes with doing a bit of regular flying anyway (which is a fair point; you can fly a C150 at 6.1 hours a year and stay alive, and many do just that, but you can't fly a decent plane at that level). The "slippery" bit means you have to plan ahead a bit but if you get that wrong you just end up overhead the target airfield, still at 5000ft and doing 149kt, so you end up looking like a d*ck, but it won't do any harm. It also means it can go into a spiral dive faster, but that's a pretty basic sort of inattention, IMHO.
What will get you will be stuff like flying into a mountain, or collecting six inches of ice and plummetting.
Speaking as someone who went from a C150/PA28 straight to a TB20, I had about 10 hrs' diff training and that was plenty for VFR flight. Then I did the IMC Rating in it (no point in flying something like that VFR-only); another 20-30hrs. No problem.
Training how to do flight/weather planning for the sort of missions one is going to want to do is something else altogether. There simply isn't anybody in the UK who knows how to do that; VFR or IFR. To this day I have not met an instructor who has even 1/10 of a clue how to do European touring flight planning combined with this level of (limited) mission capability.
I don't think it is flying a nice 150kt plane that is going to get somebody killed. 150kt v. 100kt just means you have to think 1.5 times faster but that's no big deal; it comes with doing a bit of regular flying anyway (which is a fair point; you can fly a C150 at 6.1 hours a year and stay alive, and many do just that, but you can't fly a decent plane at that level). The "slippery" bit means you have to plan ahead a bit but if you get that wrong you just end up overhead the target airfield, still at 5000ft and doing 149kt, so you end up looking like a d*ck, but it won't do any harm. It also means it can go into a spiral dive faster, but that's a pretty basic sort of inattention, IMHO.
What will get you will be stuff like flying into a mountain, or collecting six inches of ice and plummetting.
Grandpa Aerotart
The fact that the Cirrus is viewed as such a potential handfull is more a example of how truly pathetic the modern standard of pilot training has become than anything else.
The BRS has been fitted, in my opinion, to minimise the exposure of the manufacturers to the US penchant for product liability law suits. If fewer people die in their product there will be fewer law suites from the family...and the few there are can be defended with.."But we fited a parachute that could have saved them and they didn't use it..or they didn't use it until it was too late..etc"
As far as modern civvy jet handling at high mach numbers is concerned?
They handle beautifully...on the B767 I currently fly we cruise at Barber Pole...exceeding barber pole (MMO) occassions a beeper alert and nothing else...the handling is so benign they don't even have Mach trim.
I took a falcon corporate jet to M0.90 once on a test flight...the normal limit (MMO) being M0.865...slight buffet and had to push bloody hard against the mach trim but that was it.
Modern passenger jets don't have the levels of automation they have because the aircraft are hard to handfly, they are easy to hand fly. Busy, crowded airspace, complex SIDs and STARs and allowing for the lowest common denominator airline pilot is the driver behind ever more clever airliner automagics.
The BRS has been fitted, in my opinion, to minimise the exposure of the manufacturers to the US penchant for product liability law suits. If fewer people die in their product there will be fewer law suites from the family...and the few there are can be defended with.."But we fited a parachute that could have saved them and they didn't use it..or they didn't use it until it was too late..etc"
As far as modern civvy jet handling at high mach numbers is concerned?
They handle beautifully...on the B767 I currently fly we cruise at Barber Pole...exceeding barber pole (MMO) occassions a beeper alert and nothing else...the handling is so benign they don't even have Mach trim.
I took a falcon corporate jet to M0.90 once on a test flight...the normal limit (MMO) being M0.865...slight buffet and had to push bloody hard against the mach trim but that was it.
Modern passenger jets don't have the levels of automation they have because the aircraft are hard to handfly, they are easy to hand fly. Busy, crowded airspace, complex SIDs and STARs and allowing for the lowest common denominator airline pilot is the driver behind ever more clever airliner automagics.
Join Date: Apr 2003
Location: Midlands
Posts: 2,359
Likes: 0
Received 0 Likes
on
0 Posts
scooter boy
“Fixed gear hanging down into the slipstream (even the most aerodynamic gear fairings are still worse than doing what the birds do and tucking the gear away).”
Most of the modern studies would disagree. By the time you have added in the extra weight and the compromised wing design you break even on performance but lose out on useful load. You also have increased maintenance and insurance costs.
“Composite - I still don't trust it when there is any chance of lightning”
A modern carbon fiber aircraft designed for IFR is likely to survive a lightning strike much better than a 1950’s metal machine.
I find it hard to understand how you can compare a 1950;’d design with a modern aircraft, it is just a shame that it does not use a modern engine.
Rod1
“Fixed gear hanging down into the slipstream (even the most aerodynamic gear fairings are still worse than doing what the birds do and tucking the gear away).”
Most of the modern studies would disagree. By the time you have added in the extra weight and the compromised wing design you break even on performance but lose out on useful load. You also have increased maintenance and insurance costs.
“Composite - I still don't trust it when there is any chance of lightning”
A modern carbon fiber aircraft designed for IFR is likely to survive a lightning strike much better than a 1950’s metal machine.
I find it hard to understand how you can compare a 1950;’d design with a modern aircraft, it is just a shame that it does not use a modern engine.
Rod1
Join Date: Jun 2006
Location: Maders UK
Age: 57
Posts: 806
Likes: 0
Received 0 Likes
on
0 Posts
scooter boy
“Fixed gear hanging down into the slipstream (even the most aerodynamic gear fairings are still worse than doing what the birds do and tucking the gear away).”
Most of the modern studies would disagree. By the time you have added in the extra weight and the compromised wing design you break even on performance but lose out on useful load. You also have increased maintenance and insurance costs.
“Composite - I still don't trust it when there is any chance of lightning”
A modern carbon fiber aircraft designed for IFR is likely to survive a lightning strike much better than a 1950’s metal machine.
I find it hard to understand how you can compare a 1950;’d design with a modern aircraft, it is just a shame that it does not use a modern engine.
Rod1
“Fixed gear hanging down into the slipstream (even the most aerodynamic gear fairings are still worse than doing what the birds do and tucking the gear away).”
Most of the modern studies would disagree. By the time you have added in the extra weight and the compromised wing design you break even on performance but lose out on useful load. You also have increased maintenance and insurance costs.
“Composite - I still don't trust it when there is any chance of lightning”
A modern carbon fiber aircraft designed for IFR is likely to survive a lightning strike much better than a 1950’s metal machine.
I find it hard to understand how you can compare a 1950;’d design with a modern aircraft, it is just a shame that it does not use a modern engine.
Rod1
I chose a Mooney over the Cirrus, lancair columbia and twinstar for many reasons - The best way of summing up my reasoning is "Product Integrity".
Product integrity IMHO is proven over time and the long body Mooney airframe has had a pretty long shakedown in my opinion. Accident statistics will confirm that when a Mooney crashes (usually) all of the bits are usually found in the same spot - meaning bits do not fall off (unlike cirrus where ailerons have left the airframe on 2 reported occasions in the short life of this airframe without it even having been subjected to a lightning strike).
Yes, the shape of the Mooney is not new but the aerodynamic principles hold true, as does the structural integrity of the very overengineered airframe - (I have visited the factory and seen the Mooney wing structure during assembly - it truly is something to behold. I have also flown with the Mooney chief test pilot and been demonstrated the aircraft and shown that it performs exactly as published in the book - 192KTAS in the cruise - how many other manufacturers can say the same (twinstar owners case in point in particular - you max out 40 ktas slower than you guys were led to believe!).
In addition to this a friend of mine is a retired Air France 747-400 training captain (now flying instructor).
He instructs on the cirrus SR-22 and tells me that it requires far more grunt (power and fuel) to cover the same distance as even a 1970s Mooney (like his own).
If you have any doubts about composite and lightning I would recommend reading the AAIB report into the glider which was struck a year or 2 ago. Remember the Top Gear test when Hamster Hammond was put in a golf and electrocuted? Metal shields the occupants from a perm (or worse).
Sorry, but IMHO age of design is unimportant - you really want to know it won't fall apart on you and that you are not just another "test pilot" for the manufacturer - my advive is give any new design 5-10 years to be shaken down. Look at the Mooney Acclaim (237KTAS) vs anything else (except the columbia which is almost as fast).
As for the undercarriage I just hate the way fixed gear looks - call it subjective but it is just plain ugly IMHO ruining the lines of what would otherwise be stunning looking aircraft (bit like a ferrari with stabilisers or towing a caravan) - sorry but I hate the look.
What I love though is the feeling of acceleration I get when my mooney gear doors completely seal in my gear and we get underway.
SB
Join Date: May 2001
Location: 75N 16E
Age: 54
Posts: 4,729
Likes: 0
Received 0 Likes
on
0 Posts
Did you hear that she gave her instructor a present of her bra when she passed her PPL test?
The fact is that chutes, Glass cockpits and FADEC are here and will be here to stay whether anyone likes it or not. Might as well get to grips with it now. Parachutes will become commonplace on all new aeroplanes I am sure.
A lot of this "new plane" FITS training is based around the autopilot, which lets face it, is a bloody good pilot aid. For serious "go places" flight, why bother with hand flying when the auto pilot can do it? You can then spend more time concentrating on other things, like the routing, aeroplane systems etc....
On the subject of spins and the Cirrus, some people would like to believe that the spin characteristics of the aeroplane may be the cause of a number of accidents. As a comparison there is not one twin out there certified for spins, the reason being that if you put one into a spin, it won't be coming out unless you are very very lucky. So whats the problem? At least the Cirrus has a way out, you pop the chute.
It probably won't be long before we see light aeroplanes with built in protocols to prevent pilot induced unusual attitudes or stressing the aeroplane beyond limits. The G1000 is half way there, you pull up beyond about 30° or roll beyond a certain limit and a series of red arrow appear on the screen showing you which way to push or pull to correct the UA.
Join Date: Jun 2003
Location: EuroGA.org
Posts: 13,787
Likes: 0
Received 0 Likes
on
0 Posts
“Fixed gear hanging down into the slipstream (even the most aerodynamic gear fairings are still worse than doing what the birds do and tucking the gear away).”
Most of the modern studies would disagree. By the time you have added in the extra weight and the compromised wing design you break even on performance but lose out on useful load. You also have increased maintenance and insurance costs.
This one is regurgitated over and over, by fixed gear proponents or fixed gear aircraft owners.
I don't actually believe it myself. It is admittedly hard to test one way or the other, because there are so few planes which are available in an identical form but with and without fixed gear, but there are some. There is the TB10 and the TB20, fairly similar, and if you compare fuel flow rates (I don't have the data handy but remember doing it a while ago) you find that about 20-25% of engine power must be lost on the wheels. That is with wheels in generous PA28-type cowlings suitable for European-type grass airfields.
Cirrus's cowlings are more slippery than the TB10s but by compromising the tyre-cowling clearance, so you risk fouling with grass or mud, and the grass catching fire from hot brakes.
Lancair have gone nearly all the way to making the thing unusable on grass, with very tight cowlings. But their main market by far is the USA; same with Cirrus. In the USA, fixed gear is a key marketing point.
A Cirrus doesn't go any faster than a TB20, for the same fuel flow rate. Presumably the Cirrus is more slippery to start with, before they chuck it all away on the fixed gear.
For Lancair I have no data because all the fuel flow figures I have seen are for close to full bore flight, and they are understandably very high. I'd like to know what the flow rate is for 140k IAS... should be better than say a TB20 but by how much?
As to the often quoted maintenance issues: let's say you fly 150hrs/year. That will cost you about £8000/year. 20% of that is £1600/year. if you put that towards maintenance, you can have a brand new undercarriage every few years
And you will have a much better looking plane in the meantime
Most of the modern studies would disagree. By the time you have added in the extra weight and the compromised wing design you break even on performance but lose out on useful load. You also have increased maintenance and insurance costs.
This one is regurgitated over and over, by fixed gear proponents or fixed gear aircraft owners.
I don't actually believe it myself. It is admittedly hard to test one way or the other, because there are so few planes which are available in an identical form but with and without fixed gear, but there are some. There is the TB10 and the TB20, fairly similar, and if you compare fuel flow rates (I don't have the data handy but remember doing it a while ago) you find that about 20-25% of engine power must be lost on the wheels. That is with wheels in generous PA28-type cowlings suitable for European-type grass airfields.
Cirrus's cowlings are more slippery than the TB10s but by compromising the tyre-cowling clearance, so you risk fouling with grass or mud, and the grass catching fire from hot brakes.
Lancair have gone nearly all the way to making the thing unusable on grass, with very tight cowlings. But their main market by far is the USA; same with Cirrus. In the USA, fixed gear is a key marketing point.
A Cirrus doesn't go any faster than a TB20, for the same fuel flow rate. Presumably the Cirrus is more slippery to start with, before they chuck it all away on the fixed gear.
For Lancair I have no data because all the fuel flow figures I have seen are for close to full bore flight, and they are understandably very high. I'd like to know what the flow rate is for 140k IAS... should be better than say a TB20 but by how much?
As to the often quoted maintenance issues: let's say you fly 150hrs/year. That will cost you about £8000/year. 20% of that is £1600/year. if you put that towards maintenance, you can have a brand new undercarriage every few years
And you will have a much better looking plane in the meantime
Join Date: Apr 2003
Location: Midlands
Posts: 2,359
Likes: 0
Received 0 Likes
on
0 Posts
"If you have any doubts about composite and lightning I would recommend reading the AAIB report into the glider which was struck a year or 2 ago. Remember the Top Gear test when Hamster Hammond was put in a golf and electrocuted? Metal shields the occupants from a perm (or worse)."
I know about the accident, I am an ex gilder pilot and have built a composite PFA aircraft. WHY do you think metal is better than Carbon?
Rod1
I know about the accident, I am an ex gilder pilot and have built a composite PFA aircraft. WHY do you think metal is better than Carbon?
Rod1
Join Date: Jun 2006
Location: Maders UK
Age: 57
Posts: 806
Likes: 0
Received 0 Likes
on
0 Posts
Composite vs metal in lightning
Rod,
I think (and I may well be wrong) that metal acts as a conductor and carbon fibre acts as a capacitor - so carbon fibre is more likely to overheat and blow when a large discharge takes place across it than metal which shields the contents and passes the charge on to another point. The entry and exit points in the glider wreck mentioned previously were the aileron push/pull as far as I remember and the wings just vapourised leaving the metal bits behind - a perfect time to reach for the Cirrus parachute handle.
Any materials scientists out there?
I'm sure Stephen Hawking could help with this one.
Alternatively we could go to Top Gear again - perhaps Jeremy Clarkson (as Hammond is out of action for now but hopefully making a speedy recovery) might volunteer to sit in a Sinclair C5 (composite car) and repeat the Hammond lightning experiment - it certainly might improve his hairstyle!
Actually a reliant Robin (another plastic car) would be a fairer choice as it is not a convertible and would not expose the Clarkson perm to the megawattage so directly.
SB
I think (and I may well be wrong) that metal acts as a conductor and carbon fibre acts as a capacitor - so carbon fibre is more likely to overheat and blow when a large discharge takes place across it than metal which shields the contents and passes the charge on to another point. The entry and exit points in the glider wreck mentioned previously were the aileron push/pull as far as I remember and the wings just vapourised leaving the metal bits behind - a perfect time to reach for the Cirrus parachute handle.
Any materials scientists out there?
I'm sure Stephen Hawking could help with this one.
Alternatively we could go to Top Gear again - perhaps Jeremy Clarkson (as Hammond is out of action for now but hopefully making a speedy recovery) might volunteer to sit in a Sinclair C5 (composite car) and repeat the Hammond lightning experiment - it certainly might improve his hairstyle!
Actually a reliant Robin (another plastic car) would be a fairer choice as it is not a convertible and would not expose the Clarkson perm to the megawattage so directly.
SB
Join Date: Apr 2003
Location: Midlands
Posts: 2,359
Likes: 0
Received 0 Likes
on
0 Posts
Now we are getting some ware. Carbon fibre is an excellent conductor, fibreglass is not. Composite is a very wide range of materials, which is why I mentioned carbon. A Carbon structure is capable of handing lightning strikes, and the modern tests are to a higher standard than the old metal airframes were tested to. Metal aircraft sometimes survive a strike with their controls welded solid …..
Rod1
Rod1
Join Date: Jun 2003
Location: EuroGA.org
Posts: 13,787
Likes: 0
Received 0 Likes
on
0 Posts
Glass fibre + resin is an insulator, and if lightning hits it will break down the insulation, turn it into a partial conductor, and fry the material.
Carbon fibre is a relatively poor conductor, and if lightning hits then the current flow will raise the temperature of the stuff and fry it.
Metal is a good conductor.
AIUI.
That's why composite IFR planes have metal mesh embedded within the insulated sections, to conduct the current away so it cannot ionise (and destroy) the nonconductive material.
Carbon fibre is a relatively poor conductor, and if lightning hits then the current flow will raise the temperature of the stuff and fry it.
Metal is a good conductor.
AIUI.
That's why composite IFR planes have metal mesh embedded within the insulated sections, to conduct the current away so it cannot ionise (and destroy) the nonconductive material.
Join Date: Apr 2003
Location: Midlands
Posts: 2,359
Likes: 0
Received 0 Likes
on
0 Posts
Think about it. You have a carbon webb , all interconnected with resin running around the web. The Jel coat is an insulator, but is very thin and about as relevant as the non conducting paint on a metal aircraft.
During the construction of my MCR fus I touched a 1.5 v bulb to the skin at one end, a battery at the other and a wire to complete the circuit, it lit as it would if it had been two wires. The resistance was very low indeed at any point on the fus. This would be just as capable of forming a faraday cage as a metal structure. Carbon fibre is strands of carbon woven together and conducts just fine. Glass fibre, Dealin or Kevlar are all good insulators, (and composite materials along with carbon)
Rod1
During the construction of my MCR fus I touched a 1.5 v bulb to the skin at one end, a battery at the other and a wire to complete the circuit, it lit as it would if it had been two wires. The resistance was very low indeed at any point on the fus. This would be just as capable of forming a faraday cage as a metal structure. Carbon fibre is strands of carbon woven together and conducts just fine. Glass fibre, Dealin or Kevlar are all good insulators, (and composite materials along with carbon)
Rod1
Join Date: Feb 2005
Location: England
Posts: 551
Likes: 0
Received 0 Likes
on
0 Posts
Interestingly, there have been reports on the Cirrus owners' forum about p-static issues, causing heavy static interference on the radios and electrostatic discharges. Given that those aircraft don't have any static wicks, I wonder how conductive the surfaces of its wings are. In comparison, both Columbia 300/400's and Diamond DA4x's do have wicks.
Join Date: Oct 2003
Location: Ireland
Age: 44
Posts: 338
Likes: 0
Received 0 Likes
on
0 Posts
No CB will suck a 1000kg+ lump upwards, IMHO.
Firstly it's not a lump, it's an aerodynamic object. With a chute that simply means that if the descent rate is matched by a similar updraft, the the object will neither climb nor descend. If it's stronger, it will go up. Without a chute makes very little difference - once again if the updraft exceeds the descent rate you will climb. That's the basis of gliding, and it works for heavier aircraft. There have been multiple instances of jet aircraft simply not having the power to climb in a microburst, and consequently the aircraft crashed. The opposite is also true. No pilot can risk assuming he will be able to descend (or climb) in a CB.
How fast can a TB20 safely descend? 4000fpm? A CB can easily exceed a 5000fpm updraft. What was it the man said? 'Rule books are paper - they will not cushion a sudden meeting of stone and metal.'