25% Laser 200 bit by the flutter bug (amazing video)
05-25-2006, 08:59 AM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
OK, here's my $.02. First, I believe it's a 1/3 scale Laser. Second, I don't think it was going too fast for its design. Lasers can handle speed as long as they are set up correctly; non-slop linkage, flying wires, sealed hinge lines, structural soundness. A major fault in any one of these (and more) can contribute to flutter at almost any speed. It's possible that the flutter was caused by minor contributions from a combination of factors; a little play in the linkage with a couple of the 8 flying wires not snug, or/and an unnoticed bad glue joint or crack. What this video really brings home is that crap happens in this hobby, sometimes so fast you don't have time to say "OH CRA..[X(]"
05-25-2006, 10:12 AM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
ORIGINAL: ehfleming
First, I believe it's a 1/3 scale Laser.
First, I believe it's a 1/3 scale Laser.
05-25-2006, 10:32 AM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
Well think about it. When you watch an aerobatics guy doing his thing, the one thing that usually does not enter in to the equation is speed. Lots of flats, rolling circles, knife edge, (which can be a fast based manuver, but not usually) hover, and so on. All of them are power based moves. Thats why they so completely over motor the plane. You need to be able to power up through your manuvers, not down through them. If you see someone doing these manuver well, what is one thing that that pilot would do, that this pilot had no concept of? Throttle control. How many times did you hear it drop? He simply over flew the airframe. If the tailfeathers were set up wrong, then it would simply happen faster than it would if everything was perfect. So that was a factor also. But in my book (and not meaning to be harsh here) sheer inexperience caused more of a problem than anything.
05-25-2006, 11:13 AM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
Snap goes your branch! Flying wires, being used properly, would not allow the stab to flex. That is their purpose. Elevator flutter would cause them to come off, but not the whole tail section, if the wires were set up right. I seen the wires on the top side of the stab, but what of the bottom? I could not see them. If they are not there, then elevator futter would cause the stabs to flex upwards, but not down. If they were there and set up properly, plain and simple, no stab flex. I still hated to see the plane come down like that. Just my $.02
ORIGINAL: Rcpilet
After watching the slower videos;
It sure looks to me like the elevators were deflecting to max throw in opposite directions. Left was going up and the right was going down at the same time. Both elevators gyrated back and forth a couple times before the pieces started flying off.
That would certainly cause the stab to flex drastically--as dionysusbacchus said--the horizontal stab is twisting. I do agree that the twisting was what caused the stab to disentigrate. I think the elevators moving in opposite directions caused the stab to twist, and thats what led to the stab disentigrating.
I'll go way out on a limb here:
I'll bet money the guy was using a reversing Y-harness on his elevator servos, and it failed. This is CLASSIC reversing Y-harness failure mode. Both servos start freaking out and deflecting to max throw. It just so happens that they went opposite directions on this plane, and that caused the stab to twist up like a pretzel. The twisting caused the stab to disentigrate.
NTSB Report:
Mechanical/electrical equipment failure. Faulty servo reverser on elevator servos.
But, I been wrong before. Just a theory. Now, I'd really like to know if he was using a reverser on the servos. If he was--then I think I may have just found the problem.
Any way you slice it:
It sure looks to me like the elevators were deflecting pretty wildly just prior to the stab falling apart. I think that the elevators deflecting so wildly in opposite directions caused the stab to twist and thats what caused the stab to twist and disentigrate.
It's either a faulty reversing Y or both of the elevator linkages experienced catastrophic failure at the same time. Could be something as simple as not using lock nuts on the elevator linkages. The rods will vibrate around inside the clevis and strip the inside of the clevis in short order. Thats why I put locktite on my clevis, and I also use a jam nut up against the clevis with loctite on that jam nut too. Maybe the guy just ran the rods up in the clevis's and didn't lock them in.
After watching the slower videos;
It sure looks to me like the elevators were deflecting to max throw in opposite directions. Left was going up and the right was going down at the same time. Both elevators gyrated back and forth a couple times before the pieces started flying off.
That would certainly cause the stab to flex drastically--as dionysusbacchus said--the horizontal stab is twisting. I do agree that the twisting was what caused the stab to disentigrate. I think the elevators moving in opposite directions caused the stab to twist, and thats what led to the stab disentigrating.
I'll go way out on a limb here:
I'll bet money the guy was using a reversing Y-harness on his elevator servos, and it failed. This is CLASSIC reversing Y-harness failure mode. Both servos start freaking out and deflecting to max throw. It just so happens that they went opposite directions on this plane, and that caused the stab to twist up like a pretzel. The twisting caused the stab to disentigrate.
NTSB Report:
Mechanical/electrical equipment failure. Faulty servo reverser on elevator servos.
But, I been wrong before.
Just a theory. Now, I'd really like to know if he was using a reverser on the servos. If he was--then I think I may have just found the problem.Any way you slice it:
It sure looks to me like the elevators were deflecting pretty wildly just prior to the stab falling apart. I think that the elevators deflecting so wildly in opposite directions caused the stab to twist and thats what caused the stab to twist and disentigrate.
It's either a faulty reversing Y or both of the elevator linkages experienced catastrophic failure at the same time. Could be something as simple as not using lock nuts on the elevator linkages. The rods will vibrate around inside the clevis and strip the inside of the clevis in short order. Thats why I put locktite on my clevis, and I also use a jam nut up against the clevis with loctite on that jam nut too. Maybe the guy just ran the rods up in the clevis's and didn't lock them in.
05-25-2006, 11:29 AM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
ORIGINAL: Liberator
Well think about it. When you watch an aerobatics guy doing his thing, the one thing that usually does not enter in to the equation is speed. Lots of flats, rolling circles, knife edge, (which can be a fast based manuver, but not usually) hover, and so on. All of them are power based moves. Thats why they so completely over motor the plane. You need to be able to power up through your manuvers, not down through them. If you see someone doing these manuver well, what is one thing that that pilot would do, that this pilot had no concept of? Throttle control. How many times did you hear it drop? He simply over flew the airframe. If the tailfeathers were set up wrong, then it would simply happen faster than it would if everything was perfect. So that was a factor also. But in my book (and not meaning to be harsh here) sheer inexperience caused more of a problem than anything.
Well think about it. When you watch an aerobatics guy doing his thing, the one thing that usually does not enter in to the equation is speed. Lots of flats, rolling circles, knife edge, (which can be a fast based manuver, but not usually) hover, and so on. All of them are power based moves. Thats why they so completely over motor the plane. You need to be able to power up through your manuvers, not down through them. If you see someone doing these manuver well, what is one thing that that pilot would do, that this pilot had no concept of? Throttle control. How many times did you hear it drop? He simply over flew the airframe. If the tailfeathers were set up wrong, then it would simply happen faster than it would if everything was perfect. So that was a factor also. But in my book (and not meaning to be harsh here) sheer inexperience caused more of a problem than anything.
Though I agree with most of what you have said, but in this case, I must disagree. Speed was not a factor here. The stab not being stabilized and subjected to that flying speed caused the problem. Do you know if this plane was over motored, as you put it? Everytime I heard it "drop", it sounded like to me, he was getting out of the throttle.
05-25-2006, 12:09 PM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
[/quote]
Me too!! I'd have probably smacked that guy right upside the head and knocked his ballcap right off.
[/quote]
Ya! That would have helped to save that motor!
But not your *****!!!!
Do you make it a habit of smacking people around? Have you ever smacked a guy right upside the head and knocked his ballcap off? Uh? Tough guy?
I think not!
Delete this post and his!!!!!!!
05-25-2006, 12:56 PM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
Disagree away. thats what makes this place fun.
I believe though that someone said the stab WAS wired. Could they have done that wrong? You betcha, but I still tend to think that the this person just never dropped the throttle, at least the only time I heard it drop was just after take off he makes a right turn I believe and the throttle came back a little. After that it looked and sounded like it was slammin and jammin time. Have I seen these types of planes flown fast? Heck yeah, ever seen the Flying Cirkus? That was a great site and a bunch of very educational content as well. But, those guys knew how to set a plane up. I still though have never seen them do a full on full throttle dive. Even with the most expensive servos, those types of flying surfaces can and will induce flutter when flown too fast.
Bottom line, wanna go fast, get a jet.
I believe though that someone said the stab WAS wired. Could they have done that wrong? You betcha, but I still tend to think that the this person just never dropped the throttle, at least the only time I heard it drop was just after take off he makes a right turn I believe and the throttle came back a little. After that it looked and sounded like it was slammin and jammin time. Have I seen these types of planes flown fast? Heck yeah, ever seen the Flying Cirkus? That was a great site and a bunch of very educational content as well. But, those guys knew how to set a plane up. I still though have never seen them do a full on full throttle dive. Even with the most expensive servos, those types of flying surfaces can and will induce flutter when flown too fast.
Bottom line, wanna go fast, get a jet.
05-25-2006, 01:19 PM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
ORIGINAL: Liberator
Disagree away. thats what makes this place fun.
I believe though that someone said the stab WAS wired. Could they have done that wrong? You betcha, but I still tend to think that the this person just never dropped the throttle, at least the only time I heard it drop was just after take off he makes a right turn I believe and the throttle came back a little. After that it looked and sounded like it was slammin and jammin time. Have I seen these types of planes flown fast? Heck yeah, ever seen the Flying Cirkus? That was a great site and a bunch of very educational content as well. But, those guys knew how to set a plane up. I still though have never seen them do a full on full throttle dive. Even with the most expensive servos, those types of flying surfaces can and will induce flutter when flown too fast.
Bottom line, wanna go fast, get a jet.
Disagree away. thats what makes this place fun.
I believe though that someone said the stab WAS wired. Could they have done that wrong? You betcha, but I still tend to think that the this person just never dropped the throttle, at least the only time I heard it drop was just after take off he makes a right turn I believe and the throttle came back a little. After that it looked and sounded like it was slammin and jammin time. Have I seen these types of planes flown fast? Heck yeah, ever seen the Flying Cirkus? That was a great site and a bunch of very educational content as well. But, those guys knew how to set a plane up. I still though have never seen them do a full on full throttle dive. Even with the most expensive servos, those types of flying surfaces can and will induce flutter when flown too fast.
Bottom line, wanna go fast, get a jet.
If the stab was wired, properly, how could it twist so violently? No matter what the throttle setting was. So speed has nothing to do with it, if the stab was wired properly. If not, then yes, any speed kills. But it still boils down to if the stab was wired properly, not the speed. If you listen you will hear the engine building RPM, but it never gets to full. And what dive? Ya he was losing altitude, but in no way was it a dive. Watch it again. The increase in RPM may have been from the plane losing altitude and unloading the engine. Watch the plane! He was not going fast!! Not for that size and type of a plane. Oh! you did not answer my question. Do you know if the plane was over motored? BTW.... Motors are electric.
05-25-2006, 01:53 PM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
Motors are electric huh? So was that called for?
You do realize that regardless of what type of stab is in place on a given plane that enough speed will cause flutter leading up to and including catastrophic failure right?
Have you ever seen the F-15 flutter tests? Can you think of a more rigid flight platform and it still flutters?
My opinion and thats all I ever said it was, is that this individual had no exprience with this type of plane soley based on what I saw in the video. Was it over "engined"? (is that better?) Sure looks like it to me. He did blow it up after all. Had he cut the throttle and made the pass flat and level would that tail group have turned to confetti? I don't think so.
You do realize that regardless of what type of stab is in place on a given plane that enough speed will cause flutter leading up to and including catastrophic failure right?
Have you ever seen the F-15 flutter tests? Can you think of a more rigid flight platform and it still flutters?
My opinion and thats all I ever said it was, is that this individual had no exprience with this type of plane soley based on what I saw in the video. Was it over "engined"? (is that better?) Sure looks like it to me. He did blow it up after all. Had he cut the throttle and made the pass flat and level would that tail group have turned to confetti? I don't think so.
05-25-2006, 02:05 PM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
Well I went back and watched again.
Yes the pilot did reduce the throttle a few time, usually just before a turn when his speed had dropped off anyway, but he did reduce it.
Was he diving when it occured? Yup, was it a full on dive? nope, but a dive none the less. The ENGINE (see how annoying that was) was probably not quite rapped up top full, but pretty close. The thing was running pretty bad so it was probably to rich to get to full anyway.
I still think he was flying too fast. But whatever.
Yes the pilot did reduce the throttle a few time, usually just before a turn when his speed had dropped off anyway, but he did reduce it.
Was he diving when it occured? Yup, was it a full on dive? nope, but a dive none the less. The ENGINE (see how annoying that was) was probably not quite rapped up top full, but pretty close. The thing was running pretty bad so it was probably to rich to get to full anyway.
I still think he was flying too fast. But whatever.
05-25-2006, 08:26 PM
#62
RE: 25% Laser 200 bit by the flutter bug (amazing video)
Just spoke to my buddy who is building these Lasers and he viewed both versions of the tape. He disagrees that the plane was flying too fast. The pilot was probably at half throttle, as heard on the tape. The only difference in his Lasers and the one in the video is that he modifies his with counterbalances. In any case, speed is probably not a factor at all. Speed isn't really what causes flutter unless it is a critical speed where a defect will let flutter manifest. But it isn't a situation that caused purely by some speed.
I was wrong about gaps causing flutter. It so happens that my friends brother is a stability and controls expert, and he has asked his brother quite a lot about flutter. I had a plane that experienced elevator flutter and crashed twice. So, he asked when we were trying to figure out why the plane fluttered and crashed. The only contribution to flutter that a gap has is if the hinges are off center, and the gap allows uneven airflow over and under the hinges/control surface which is a flutter situation waiting to happen.
I was wrong about gaps causing flutter. It so happens that my friends brother is a stability and controls expert, and he has asked his brother quite a lot about flutter. I had a plane that experienced elevator flutter and crashed twice. So, he asked when we were trying to figure out why the plane fluttered and crashed. The only contribution to flutter that a gap has is if the hinges are off center, and the gap allows uneven airflow over and under the hinges/control surface which is a flutter situation waiting to happen.
05-25-2006, 09:57 PM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
After talking with a few local guys today, who knew the previous owner of the 1/3 Scale Laser in question, I believe they said it had been recovered before. Could it be possible that the stab was weakened by an exacto blade, when the first covering was cut off, along the edge where it was glued in at? One of the guys I talked with today, said that doing that, is just like cutting plate glass, make a score and it will snap right into.
Later,
Omaha
Later,
Omaha
05-25-2006, 10:13 PM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
Hmm half throttle huh? Did that really sound like half throttle to you?
Also notice the way the flutter starts. Its not the control surfaces that seem to go first, it is oscillating up and down at the tips of the stab. Keep in mind, we are dealing with highly exaggerated surface areas on these types of planes. That is what allows them to be a tumble weed. To say that speed does not cause flutter isnt really telling the whole story. Speed essentially says "if there is a problem here, I am going to make it worse." All the problem has to be is big surfaces.
I'm going to ask Dick Hanson to take a look at it. He has forgotton more than I will ever know about all things Plane.
Also notice the way the flutter starts. Its not the control surfaces that seem to go first, it is oscillating up and down at the tips of the stab. Keep in mind, we are dealing with highly exaggerated surface areas on these types of planes. That is what allows them to be a tumble weed. To say that speed does not cause flutter isnt really telling the whole story. Speed essentially says "if there is a problem here, I am going to make it worse." All the problem has to be is big surfaces.
I'm going to ask Dick Hanson to take a look at it. He has forgotton more than I will ever know about all things Plane.
05-25-2006, 10:15 PM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
You bet Omaha, if you have that scoring in place, AND you fly the plane beyond its airframe a bit, then 2+2 will probably make 4.
05-26-2006, 08:29 AM
#66
RE: 25% Laser 200 bit by the flutter bug (amazing video)
Liberator--
from the sound on the tape -- the engine was turning faster than at any other time - meaning it was unloading - typical in a dive.
Common error.
This type flying unloads the entire airframe - meaning the diving model has least induced drag ( not as much lift required ) and the trim drag (really inportant part here ) is at zero or close to it .
So-
a flat plate is seeing almost equal presure on both sides - setting the stage for a rapidly shifting load top to bottom etc.
this type of resonance is usually going to self excite and increase till failure occurs.
Almost all tail flutters occur on a unloaded dive -or- just after levelling out from a split S - again, unloading the tailplanes.
bad linkage/servos / poor linkage geometry/ loose wires/etc., all of or part of these can cause flutter .
the gap - forget it .
Sealing the gap may reduce flex, effectively stiffening the tail. If you build properly, no seals are needed . If you want to seal go ahead -on loose gaps it does improve response.
flying wires , to be even marginally effective , must be very solid and tight -otherwise -worthless.
Wanting to do a ripping pass is common amongst flyers -it is exciting - tho the model may be exiting-------
from the sound on the tape -- the engine was turning faster than at any other time - meaning it was unloading - typical in a dive.
Common error.
This type flying unloads the entire airframe - meaning the diving model has least induced drag ( not as much lift required ) and the trim drag (really inportant part here ) is at zero or close to it .
So-
a flat plate is seeing almost equal presure on both sides - setting the stage for a rapidly shifting load top to bottom etc.
this type of resonance is usually going to self excite and increase till failure occurs.
Almost all tail flutters occur on a unloaded dive -or- just after levelling out from a split S - again, unloading the tailplanes.
bad linkage/servos / poor linkage geometry/ loose wires/etc., all of or part of these can cause flutter .
the gap - forget it .
Sealing the gap may reduce flex, effectively stiffening the tail. If you build properly, no seals are needed . If you want to seal go ahead -on loose gaps it does improve response.
flying wires , to be even marginally effective , must be very solid and tight -otherwise -worthless.
Wanting to do a ripping pass is common amongst flyers -it is exciting - tho the model may be exiting-------
05-26-2006, 09:46 AM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
I just rewatched the video... by FAR the best part is just after the fuse hits the ground... there is about 1 second of silence and someone simply says...... "oooooph"
Priceless
and we have all said it at some time!
Priceless
and we have all said it at some time!
05-26-2006, 11:09 AM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
Absolutely!!!
I also liked it when it got played over in slow motion "ooooooooooooooooooooooooooooooooooooooooooooooooph"
I also liked it when it got played over in slow motion "ooooooooooooooooooooooooooooooooooooooooooooooooph"
05-26-2006, 08:17 PM
#70
RE: 25% Laser 200 bit by the flutter bug (amazing video)
ORIGINAL: rcs36
Me too!! I'd have probably smacked that guy right upside the head and knocked his ballcap right off.
Ya! That would have helped to save that motor!
But not your *****!!!!
Do you make it a habit of smacking people around? Have you ever smacked a guy right upside the head and knocked his ballcap off? Uh? Tough guy?
I think not!
Delete this post and his!!!!!!!
Me too!! I'd have probably smacked that guy right upside the head and knocked his ballcap right off.
But not your *****!!!!
Do you make it a habit of smacking people around? Have you ever smacked a guy right upside the head and knocked his ballcap off? Uh? Tough guy?
I think not!
Delete this post and his!!!!!!!
05-26-2006, 08:37 PM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
ORIGINAL: bdavison
Guys, I have a great tip for you.
Everyone knows a majority of flutter results from air getting up into the gap between the hinge line.
There is a very easy solution though.
Dubro Electric Hinge Tape.
This tape is 3M Blenderm(originally medical tape), Dubro packages rolls of it for electric flyers to use to do the hinges on small foamies.
There are a couple of pilots here that have used this tape along the hinge lines on their big gas planes. It is fuel proof and wont come off. When inserted into the hinge gap, it seals it up real good.
I would highly recommend to anyone looking for a solution, to try this stuff.
Its also got a very nice clear matte finish so it doesnt look unsightly.
I know of a 40% Extra that uses this method to seal up the hinge gaps, and so far....zero problems.
Guys, I have a great tip for you.
Everyone knows a majority of flutter results from air getting up into the gap between the hinge line.
There is a very easy solution though.
Dubro Electric Hinge Tape.
This tape is 3M Blenderm(originally medical tape), Dubro packages rolls of it for electric flyers to use to do the hinges on small foamies.
There are a couple of pilots here that have used this tape along the hinge lines on their big gas planes. It is fuel proof and wont come off. When inserted into the hinge gap, it seals it up real good.
I would highly recommend to anyone looking for a solution, to try this stuff.
Its also got a very nice clear matte finish so it doesnt look unsightly.
I know of a 40% Extra that uses this method to seal up the hinge gaps, and so far....zero problems.
Thats exactly what I use on my Yak and Edge..works better than clear Ultracote
05-27-2006, 09:24 PM
#72
RE: 25% Laser 200 bit by the flutter bug (amazing video)
I didn't *like* any part of the sequence as I am aware of how much was lost in that crash....even when listening in slow motion.
Looking at the film again, I don't think he was in a deep dive, but rather lost about 10 feet in the tight turn. He looked like he was level for a second or two before the flutter started. I know that I've watched 3 or 4 of these Lasers do much wilder stuff and keep on flying fine.
Flutter is basically a harmonic frequency that occurs, hopefully at a point where you will not be flying. Poorly installed hinge lines or slop anywhere in the linkage train can cause the resonance to start. High speed is sometimes immaterial. It doesn't have to be a high speed. For instance, my Fantasy would usually flutter around half throttle. It only fluttered the last time at high speed. The other times were when the model was balanced properly and usually when in a very slight nose down attitude. It fluttered a few times before it crashed the first time. There was a mistake when the plane was balanced the first time and it never fluttered until I found the error. The same thing happened again when another balancing error was found after the rebuild. Skyshark RC bought the design and the owner wrote that it took a redesign of the aft fuselage with an extra former to prevent the flutter characteristics of the original design.
Looking at the film again, I don't think he was in a deep dive, but rather lost about 10 feet in the tight turn. He looked like he was level for a second or two before the flutter started. I know that I've watched 3 or 4 of these Lasers do much wilder stuff and keep on flying fine.
Flutter is basically a harmonic frequency that occurs, hopefully at a point where you will not be flying. Poorly installed hinge lines or slop anywhere in the linkage train can cause the resonance to start. High speed is sometimes immaterial. It doesn't have to be a high speed. For instance, my Fantasy would usually flutter around half throttle. It only fluttered the last time at high speed. The other times were when the model was balanced properly and usually when in a very slight nose down attitude. It fluttered a few times before it crashed the first time. There was a mistake when the plane was balanced the first time and it never fluttered until I found the error. The same thing happened again when another balancing error was found after the rebuild. Skyshark RC bought the design and the owner wrote that it took a redesign of the aft fuselage with an extra former to prevent the flutter characteristics of the original design.
05-28-2006, 07:10 AM
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
hi again everyone
listen it doesnt make any difference if you have flying wires or not, if you could get an iron control surface to fly, in an enviroment where flutter would occur the failure would look the same.
the one thing that seems to be a sticking point in peoples mind is the twisting that is taking place. without a time line its impossible to tell what is failing when. but there are multiple things taking place. 1st you can see the flutter begin. and there should be a buzzing sound begining. 2nd now something else has failed, a hinge? the trailing edge of the stab? i dont know but the orginal problem (flutter) is still present but now has increased along with the buzzing sound and with the secondary failure has started the twisting motion the twist magnifys itself while the flutter is still there ripping apart the horizontal stab and weakens the veritcal stab and rudder. and you can see the results. which is step 3
I never said the airplane was being flown to fast. I said it was at higher airspeed. it flew to the speed that flutter got it. flutter airspeed will always be slower than the max airspeed of the airframe. (think about that one) in other words every airframe has a speed that flutter will become a factor. you want that airspeed to be above what the airframe can attain.
like so many things in aviation flutter depends on alot of factors. barometric pressure, speed,direction of wind. speed, heading of the aircraft realitive to wind direction . gap in the control surface. etc etc.
bottom line is if you have a large enough gap. and condtions are right there will be another thread like this one. with people wondering what happened.
once you see flutter in person you will believe.
listen it doesnt make any difference if you have flying wires or not, if you could get an iron control surface to fly, in an enviroment where flutter would occur the failure would look the same.
the one thing that seems to be a sticking point in peoples mind is the twisting that is taking place. without a time line its impossible to tell what is failing when. but there are multiple things taking place. 1st you can see the flutter begin. and there should be a buzzing sound begining. 2nd now something else has failed, a hinge? the trailing edge of the stab? i dont know but the orginal problem (flutter) is still present but now has increased along with the buzzing sound and with the secondary failure has started the twisting motion the twist magnifys itself while the flutter is still there ripping apart the horizontal stab and weakens the veritcal stab and rudder. and you can see the results. which is step 3
I never said the airplane was being flown to fast. I said it was at higher airspeed. it flew to the speed that flutter got it. flutter airspeed will always be slower than the max airspeed of the airframe. (think about that one) in other words every airframe has a speed that flutter will become a factor. you want that airspeed to be above what the airframe can attain.
like so many things in aviation flutter depends on alot of factors. barometric pressure, speed,direction of wind. speed, heading of the aircraft realitive to wind direction . gap in the control surface. etc etc.
bottom line is if you have a large enough gap. and condtions are right there will be another thread like this one. with people wondering what happened.
once you see flutter in person you will believe.
05-29-2006, 09:34 PM
#74
RE: 25% Laser 200 bit by the flutter bug (amazing video)
If the Laser in the video is a Lanier kit, then I saw 2 of them today fly 2 to 3 times faster in all kinds of dives, pull ups, elevators, blenders, etc and neither fluttered. Both were modified with counterbalances and had Brisson 3.2 engines. Lots of full throttle stuff.
05-29-2006, 09:59 PM
#75
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RE: 25% Laser 200 bit by the flutter bug (amazing video)
If speed isnt a factor, riddle me this.
Did you ever see a plane flutter to death...in the hangar?
Dick Hanson is spot on.
Did you ever see a plane flutter to death...in the hangar?
Dick Hanson is spot on.