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Old Oct 26, 2008, 07:41 AM
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Lovely! But that proves it, a 2nd wing is only weighing the plane down I'll go chop up my planes now and be a happy single wing flyer from now on ...

Cheers,

Sander.
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Old Oct 26, 2008, 09:35 AM
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The wing didn't "fall off" it was BROKEN off ...

Sorry Jim, but I find it unbelievable that NO ONE has called you to the carpet for conducting a snap roll at full throttle and, presumably, at a high rate of speed such that it exceeded the structural limit of the wings.

Given your extensive model aviation experience, as well as your experience with full scale aviation, you should have known better! Especially considering the recent repairs done to the wing!!

Don't take this personally, but everyone here is putting you on a pedestal for a good save, when in fact you broke a buddy's perfectly good airplane through bad judgment and poor technique.

I know some folks will suggest Iím being a first-class jerk, but everyone should spend some time reading this forum:

http://www.airtalk.org/1-vt16256.html?start=0

Here is the disclaimer Ö this forum is discussing full scale aircraft and we all know that most models are built to withstand higher G loads. However, the basic principle is still the same Ö snap rolls should not be conducted at speeds greater than 2 times the stall speed. Since most of us donít have live telemetry showing the airspeed of the model, a general rule of Ĺ throttle in level flight would be safe. On down lines, itís safe to say that the throttle should not be greater than Ĺ as well.

If you conduct snaps above these speeds, you are flying at risk and will likely break the airplane. This video is a perfect case-in-point! It might not break the first time you do a high speed snap, but over time you will certainly fatigue the airplane to the point of structural failure.

So, good save Jim, but shame on you for creating this situation in the first place.

I will now put on my flame retardant suit ... flame on everybody ...
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Old Oct 26, 2008, 10:16 AM
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Quote:
Originally Posted by AIVIA
Sorry Jim, but I find it unbelievable that NO ONE has called you to the carpet for conducting a snap roll at full throttle and, presumably, at a high rate of speed such that it exceeded the structural limit of the wings.

Given your extensive model aviation experience, as well as your experience with full scale aviation, you should have known better! Especially considering the recent repairs done to the wing!!

Don't take this personally, but everyone here is putting you on a pedestal for a good save, when in fact you broke a buddy's perfectly good airplane through bad judgment and poor technique.

I know some folks will suggest Iím being a first-class jerk, but everyone should spend some time reading this forum:

http://www.airtalk.org/1-vt16256.html?start=0

Here is the disclaimer Ö this forum is discussing full scale aircraft and we all know that most models are built to withstand higher G loads. However, the basic principle is still the same Ö snap rolls should not be conducted at speeds greater than 2 times the stall speed. Since most of us donít have live telemetry showing the airspeed of the model, a general rule of Ĺ throttle in level flight would be safe. On down lines, itís safe to say that the throttle should not be greater than Ĺ as well.

If you conduct snaps above these speeds, you are flying at risk and will likely break the airplane. This video is a perfect case-in-point! It might not break the first time you do a high speed snap, but over time you will certainly fatigue the airplane to the point of structural failure.

So, good save Jim, but shame on you for creating this situation in the first place.

I will now put on my flame retardant suit ... flame on everybody ...


Well yeah, so what you are suggesting is that everyone with an Extra/Yak/ Or a 3d capable model, should only putt putt around in circles, as to stay safe with an airplane?!
That's what scale Cessna's are for!
You are telling everyone to do no manouvers!
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Old Oct 26, 2008, 11:05 AM
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Well yeah, so what you are suggesting is that everyone with an Extra/Yak/ Or a 3d capable model, should only putt putt around in circles, as to stay safe with an airplane?!
At what point did I suggest that? EVERY airplane, from Trainers to 3D acro machines, has structural limits ... I'm suggesting Jim exceeded those when he snapped the airplane at full throttle. It struck me funny that everyone was patting him on the back for the save, when it was poor technique that got him in that position to begin with. Again, my point was ... stay within the designed structural limits of the airplane you are flying and you won't have to resort to the "heroics" of landing an airplane with only 1 wing.

Quote:
You are telling everyone to do no manouvers!
Again, where have I suggested that? I've been an acro guy for 20 years and I've NEVER broken an airplane in flight. Why? Because I understand the correlation of airspeed, G loading, and structural limits. All too often modelers break airplanes because they don't understand this simple concept. For whatever reason, many modelers think a 3D or aerobatic airplane is indestructible and you can just bang the sticks around at any airspeed and it should hold up. Far from the truth, as Jim has proven.

By the way, it's maneuvers not manouvers.

And one more thing ... I don't know Jim and my post isn't aimed at him personally. In fact, I greatly enjoyed his article in Sport Aerobatics and applaud his efforts to bridge the two sports together. I would hope that given his experience with full scale aerobatics, he would use this platform to help educate modelers on the importance of aircraft limitations. I assure you, he flies Russian Thunder with more respect than he did Keith's Yak. But why should it be different, just because your butt is in the seat? Do we really need a 30% or 40% acro machine, with only 1 wing, crashing into the pitts or spectator area? Thankfully, Jim's skills allowed him to dodge that bullet.
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Old Oct 26, 2008, 11:16 AM
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Again, my point was ... stay within the designed structural limits of the airplane you are flying and you won't have to resort to the "heroics" of landing an airplane with only 1 wing.
I'm going to respectfully have to disagree with you here. How is one to know the structural limits of a model airplane? Due to the scale factor they can take far more 'abuse' that a full scale airplane, hence other than trail-and-error it is hard to guesstimate how well the wing (or any other part of the airplane) is going to hold up under stress.

I routinely put my planes through a level of stress that would rip a full scale airplane to bits and pieces and up until now I haven't lost any due to structural failure. So to my opinion and experience Jim wasn't doing anything wrong here, frankly he probably saved the plane from a crash at a later date that might not have ended this well as the pilot would've been his buddy, who most likely has not practized this scenario in the simulator, hence kudos to Jim for saving his buddy's airplane.

Cheers,

Sander.
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Old Oct 26, 2008, 11:28 AM
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Quote:
Originally Posted by ssassen
I'm going to respectfully have to disagree with you here. How is one to know the structural limits of a model airplane? Due to the scale factor they can take far more 'abuse' that a full scale airplane, hence other than trail-and-error it is hard to guesstimate how well the wing (or any other part of the airplane) is going to hold up under stress.

I routinely put my planes through a level of stress that would rip a full scale airplane to bits and pieces and up until now I haven't lost any due to structural failure. So to my opinion and experience Jim wasn't doing anything wrong here, frankly he probably saved the plane from a crash at a later date that might not have ended this well as the pilot would've been his buddy, who most likely has not practized this scenario in the simulator, hence kudos to Jim for saving his buddy's airplane.

Cheers,

Sander.
Exactly what I meant.

Quote:
Originally Posted by AIVIA
Sorry Jim, but I find it unbelievable that NO ONE has called you to the carpet for conducting a snap roll at full throttle and, presumably, at a high rate of speed such that it exceeded the structural limit of the wings.

Given your extensive model aviation experience, as well as your experience with full scale aviation, you should have known better! Especially considering the recent repairs done to the wing!!

Don't take this personally, but everyone here is putting you on a pedestal for a good save, when in fact you broke a buddy's perfectly good airplane through bad judgment and poor technique.

I know some folks will suggest Iím being a first-class jerk, but everyone should spend some time reading this forum:

http://www.airtalk.org/1-vt16256.html?start=0

Here is the disclaimer Ö this forum is discussing full scale aircraft and we all know that most models are built to withstand higher G loads. However, the basic principle is still the same Ö snap rolls should not be conducted at speeds greater than 2 times the stall speed. Since most of us donít have live telemetry showing the airspeed of the model, a general rule of Ĺ throttle in level flight would be safe. On down lines, itís safe to say that the throttle should not be greater than Ĺ as well.

If you conduct snaps above these speeds, you are flying at risk and will likely break the airplane. This video is a perfect case-in-point! It might not break the first time you do a high speed snap, but over time you will certainly fatigue the airplane to the point of structural failure.

So, good save Jim, but shame on you for creating this situation in the first place.

I will now put on my flame retardant suit ... flame on everybody ...

How do we know the limits??
Are we supposed to buy some machine that will keep pulling on the plane until it snaps? Then we will know??
Many modelers probably don't worry about the limits, if the plane was high quality [Maybe Jim skipped some steps(I don't know)] and he did that maneuver (Sorry if I spelled it wrong, No one is perfect) this would have never happened.
I see people at the field do WAY more stressful things to their planes, without EVEN CONSIDERING the plane might fall apart.
But from your post it seemed as if everyone should monitor their planes (Which they all do) But to a point where a person has to obsess over their plane and fix every last tiny crack. [Which in reality will do NO HARM]
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Old Oct 26, 2008, 12:34 PM
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[QUOTE]How is one to know the structural limits of a model airplane? Due to the scale factor they can take far more 'abuse' that a full scale airplane, hence other than trail-and-error it is hard to guesstimate how well the wing (or any other part of the airplane) is going to hold up under stress.[QUOTE]

Sander, you make a great point. It's virtually impossible for one to know, with any degree of specificity, the structural limits of the airplane they are flying. And even more so, it's impossible to tell if they are nearing those limits while in flight. Honestly, it takes experience, which it seems you have as well as Jim. It takes an understanding of structural design, not at an engineering level, but a basic understanding of what a strong structure looks like versus one that was built light (intentionally) for improved aerobatic performance. The variables get even harder to sort out if the airplane was built from a kit vice an ARF. So, when you have inexperienced modelers out there "abusing" their airplanes, it creates a safety scenario that concerns me. Simulator practice is a great way to mitigate what we can't always predict. Not abusing your equipment and being smart is another way.

MarcinB1995, you made my point for me:
Quote:
Many modelers probably don't worry about the limits, if the plane was high quality [Maybe Jim skipped some steps(I don't know)] and he did that maneuver (Sorry if I spelled it wrong, No one is perfect) this would have never happened.
I see people at the field do WAY more stressful things to their planes, without EVEN CONSIDERING the plane might fall apart.
Maybe it's time folks start thinking about limits. I think we can all agree that airplanes do have some kind of structural limits, right? The people that don't consider this (and you admitted there are "many") are usually the first ones to flame a manufacturer on RCGroups or RCU for an ARF that came apart, after they probably abused it. Is it a manufacturing defect or brain defect? I'm guessing many wouldn't man-up to a brain defect, pilot error, or poor flying technique.

Quote:
But from your post it seemed as if everyone should monitor their planes (Which they all do) But to a point where a person has to obsess over their plane and fix every last tiny crack. [Which in reality will do NO HARM]
Come on now, I'm not suggesting people "obsess" over every crack. But you should know the difference between structural repairs (as was done to one of the wings on the Yak Jim was flying) and repairs to non-structural aspects of the airplane that will do "NO HARM" as you stated. Just like structural limits, how does one tell if a structural repair is strong enough to hold up to the same stresses as it did when new? You really can't, without destructive testing, which is impractical. So, what do you do? Go out and abuse it and see what happens ... Git-R-Done style? Or, do you apply a little common sense and treat the airplane with some respect, by throttling back a bit and not abusing it so hard? And no, I'm not suggesting you "putt putt" around, but for God's sake, don't snap the thing a full throttle just because everything "felt good" and it was "grooving" after a few high speed passes!

Oh, another point, if I may: if you decide to abuse an airplane like that (meaning one that was recently repaired), make sure it's YOUR airplane and not your buddy's! Honestly, it's comical ... "I ripped the wing of my buddy's airplane, but made an amazing save ... hoorah for me!"
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Old Oct 26, 2008, 12:52 PM
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we can all agree that airplanes do have some kind of structural limits, right?
Of course, and I think you can safely expect that a plane which is labelled as '3D acrobatic' with a recommended flying weight will hold up under stress even when doing demanding 3D maneuvres with it.

However since these are model aircraft and require some amount of DIY to get them flyable it also comes down to how well it is constructed by the pilot. Using the wrong type of glue for example to glue some essential parts could reduce the ability of the airplane to withstand stress and cause for failures.

So it is a combination of common sense, experience and not straying to far from the recommended setup in my book.

Cheers,

Sander.
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Old Oct 26, 2008, 01:48 PM
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[QUOTE=AIVIA][QUOTE]How is one to know the structural limits of a model airplane? Due to the scale factor they can take far more 'abuse' that a full scale airplane, hence other than trail-and-error it is hard to guesstimate how well the wing (or any other part of the airplane) is going to hold up under stress.
Quote:

Sander, you make a great point. It's virtually impossible for one to know, with any degree of specificity, the structural limits of the airplane they are flying. And even more so, it's impossible to tell if they are nearing those limits while in flight. Honestly, it takes experience, which it seems you have as well as Jim. It takes an understanding of structural design, not at an engineering level, but a basic understanding of what a strong structure looks like versus one that was built light (intentionally) for improved aerobatic performance. The variables get even harder to sort out if the airplane was built from a kit vice an ARF. So, when you have inexperienced modelers out there "abusing" their airplanes, it creates a safety scenario that concerns me. Simulator practice is a great way to mitigate what we can't always predict. Not abusing your equipment and being smart is another way.

MarcinB1995, you made my point for me:


Maybe it's time folks start thinking about limits. I think we can all agree that airplanes do have some kind of structural limits, right? The people that don't consider this (and you admitted there are "many") are usually the first ones to flame a manufacturer on RCGroups or RCU for an ARF that came apart, after they probably abused it. Is it a manufacturing defect or brain defect? I'm guessing many wouldn't man-up to a brain defect, pilot error, or poor flying technique.



Come on now, I'm not suggesting people "obsess" over every crack. But you should know the difference between structural repairs (as was done to one of the wings on the Yak Jim was flying) and repairs to non-structural aspects of the airplane that will do "NO HARM" as you stated. Just like structural limits, how does one tell if a structural repair is strong enough to hold up to the same stresses as it did when new? You really can't, without destructive testing, which is impractical. So, what do you do? Go out and abuse it and see what happens ... Git-R-Done style? Or, do you apply a little common sense and treat the airplane with some respect, by throttling back a bit and not abusing it so hard? And no, I'm not suggesting you "putt putt" around, but for God's sake, don't snap the thing a full throttle just because everything "felt good" and it was "grooving" after a few high speed passes!

Oh, another point, if I may: if you decide to abuse an airplane like that (meaning one that was recently repaired), make sure it's YOUR airplane and not your buddy's! Honestly, it's comical ... "I ripped the wing of my buddy's airplane, but made an amazing save ... hoorah for me!"

Yeah you're right.
I first fly around, then I check over the plane, and then I go and do some stunts, I don't just send it up and HOPE that it will keep together, though.
I do not know if Jim did a snap roll at no throttle, full throttle, or even half throttle as the video doesn't show that. He should of started by "Putting" around, then check the plane, do mild maneuvers, check the plane, then go crazy after once again checking over the plane.
If he did that he can safely say it wasn't his fault and he can be considered an RC "Hero" If he just took off and went crazy, we can obviously see who's fault it was.
By the way, Why was Jim flying his buddies plane after repairs instead of his buddy




Quote:
Originally Posted by ssassen
Of course, and I think you can safely expect that a plane which is labelled as '3D acrobatic' with a recommended flying weight will hold up under stress even when doing demanding 3D maneuvres with it.

However since these are model aircraft and require some amount of DIY to get them flyable it also comes down to how well it is constructed by the pilot. Using the wrong type of glue for example to glue some essential parts could reduce the ability of the airplane to withstand stress and cause for failures.

So it is a combination of common sense, experience and not straying to far from the recommended setup in my book.

Cheers,

Sander.
That is also a good point. If you buy a 3d ready plane, you shouldn't have to worry that your plane will fall apart during a rolling circle.
But if you buy an Avistar and try to do 3d with that, and the plane breaks apart, it is probably your fault.
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Old Oct 26, 2008, 02:14 PM
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I certainly did exceed the structural limits of the airplane. The incident is a chilling reminder of what could happen to me if I exceeded the limits of Russian Thunder.

However, I think all of that goes without saying.

Jim
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Old Oct 26, 2008, 04:42 PM
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I certainly did exceed the structural limits of the airplane. The incident is a chilling reminder of what could happen to me if I exceeded the limits of Russian Thunder.

However, I think all of that goes without saying.

Jim
So what's the moral of the story Jim??
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Old Oct 26, 2008, 04:47 PM
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Sounds to me like the moral of the story is that an R/C plane is replaceable but the Russian Thunder and her pilot are not.
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Old Oct 26, 2008, 05:32 PM
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Originally Posted by BoneDoc
Freakin cool Jim! It looks like there's not enough wing tube length there .
I concur with Bonesy on lack of tube length for hotdoggin' manoeuvres or is that manoovers
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Old Oct 26, 2008, 06:10 PM
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Originally Posted by SteveM732
Sounds to me like the moral of the story is that an R/C plane is replaceable but the Russian Thunder and her pilot are not.
And that next time.... Jim should try a NO WING landing!
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Old Oct 26, 2008, 06:55 PM
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Originally Posted by MarcinB1995
And that next time.... Jim should try a NO WING landing!
I would of thought catching it from a no-wings prophang would work too!

Bonesy uses cracks in the runway for wing removal!

Maggie.
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