motzartmerv

For the less educated amongst us, what is the thermal expansion rate of the cylinder heads, compared with the crank case?

Yes oscar. We have seen several examples of material loss on the crank case halves due to fretting which closes the gaps on the bearing journals and causes some big problems. Retaining the crank case AND the cylinder heads with the same bolts does not help the problem. I dont know if the engine thats failed here is the infamous one you speak of, I hope not:)

It's all good mate. She will pull thru!! Keep ya chin up alf. U have a lot of mates here.

Interesting comment oscar. Doesnt reflect conversations Ive had with him, and probably about the actual engine which is the star of this thread:).

hard to say. I havnt spoken to the operator yet, but I doubt they would know too much. Im not even sure if its one of the school aeroplanes (at a school where I used to work). They had some high time Jab 160's running on avgas in the training environment. Not many other facts about the life of the plane without knowing exactly which one it was. All were LAME maintained, one out of 3 was GA registered. All would be over 1000 hours TT, with none of them being on their original engine. I will talk to the Chief tomorrow and see whats been discovered.

Dave?

Rememebr, its never LOST, your just temporarily unsure of its position...

Ummm.. Would you like a briefing?

Glad they are ok. Wondering who the young Instructor is. I only know of a slightly aged instructor working in jabs at Camden. Nothing to add re the jabs, but to say nothing surprising.

I did, i offered, several times. Met with the usual stone wall. One day ill be one of the boys!!...haha:amazon:

I think if its a clear cut safety issue, ie something on the aeroplane has failed, then the ATSB (or whoever) has a responsibility to get the inof out ASAP. That, after all is the point of any investigation, to hopefully prevent it happening again. I was involved in an investigation of a double fatal helicopter prang a couple of years ago, everybody pretty much knew on the day why the crash occured. But because it was quite clearly a human error, the investigation didnt say much about it for about a year. Where as the identical accident that occurred one year (to the day) previously (another R44 laid over and killed 2 people), was found very quickly to be a component failure. This finding was released very quickly in the prelim report. Mind you. The actual cause of death in BOTH (and many many more) was the post impact fire, not the accident itself. With all the weight of evidence, factual findings and dozens of lives lost around the world, it still took many many deaths before CASA stepped in and made a safety decision to upgrade the SB to and AD regarding the fuel tanks. And, I might add, it was only after considerable pressure from the community that they did act. The point im making is, knowledge is the key. We can't hold our breath waiting for CASA or the ATSB to keep us safe. Its simply not going to happen. But, with knowledge, we can make decisions ourselves. There is no way in the world I would have sat in an R44 without the bladder tank mod done, even BEFORE its became an AD. because I had knowledge of what to expect if it even just laid on its side.

121 kts cruise? Typical website fluff..

Good move..Still reckon we need to bring back the "tossa" icon tho..Was very.....Usefull sometimes!!...

hahaha... Bloody strong aeroplane to look like that after a "crash" and a fire. Wow.!!! What type is it? Looks like maybe a storm, but not seen the canopy design on one before.

Thats good HIC. Thanks. I see what your saying, now that you've actually said it. Thats an excellent description. I still maintain that being lighter, the aeroplane will resist change in ALL directions, AND, Attitudes much less then it will at higher weights. That includes increasing AofA. VA is an issue for ALL control inputs, not just the elevator. How can we explain these limitations.?

Yes. I get that. Thank you. But seeing as the entire problem relates to controls and their use, I was discussing its use in that particular situation. The elevator does provide a turning moment about the lateral axis, if you want to be picky..

HIC Mate. Im not going to make this personal. If you have something to add then i respectfully ask you get to the point. I can sit here picking holes in your statements too, all day, but its not helping clear the matter up is it? Ive offered a point of view, what exactly is your point of view? No. The wings are not subject to the same loads at all. Without a change there is no increase in load. Again, and im getting blue in the face here, without change there is no increase in load. No change in AOFA no load increase. No change in trajectory (thanx nev) no load increase. Ive never seen a "trying" to attain new direction in any formula. The physics relating to this problem can be summed up in two basic (high school ) formulas. p=mv f=ma The difference between the two, but more so the relationship between the two explains this phenomena very well, and one of them answers your last question.

Thank you Nev. And your post brings the second part of the equation into it. We arent simply talking about control inputs. We are also talking about turbulence etc. ANYTHING that causes the aeroplane to accelerate in ANY direction, if too quickly, will have potential to cause problems. Not just the controls. A heavy object will resist acceleration more then a light object. Very very simple physics. And the reason as I get older (and increase mass) I resist change in both acceleration and 'the world' ...lol

A bit circular there HIC. Does the elevator apply a force or not? In one sentence you stated it doesnt and then it does. (not a great instructional technique) I would simply say that yes it certainly does apply a force. I was attempting to keep the problem simple to clarify it. If we are looking for students to understand the issue then the KISS principle should be applied. How quickly the aeroplane ACTUALLY responds to AOA increase is the exact issue we are trying to understand. The load factor will not increase until the aeroplane describes a new direction, so there for no, the wings will not tear off UNTIL the new direction is attained. Which is the whole point behind understanding inertia.. The lighter plane WILL respond to change much faster due to its lack of inertia and there for the LOAD factor WILL increase to critical levels. ..

Hic, I was replying to your comments on the matter ;)You contended comments made by myself and other instructors, so I was replying to that. If you dont wish to discuss it...... I think it was me who highlighted the knowledge gap and offered some ways to approach the problem in the other thread. The idea that its only related to stalling speed changes with weight is a common 'miss conception' and my point the whole time has been that inertia is the biggest factor when talking about load limits and manourvering. The accident referenced in Dj's article above highlights this precisely where an airliner was misshandled to the point of structural failure well below the quoted VA of the aircraft. And it had nothing to do with the stall, or the stall speed. To explain it, imagine an aeroplane that is massively massively heavy. Hundreds of times over its MTOW. Ignore the obvious problems with this and just think about whats going to happen when the stick is suddenly pulled back. If the aeroplane is super super heavy, its inertia will cause it to continue on a straight line ( as defined by newtons first law) until its acted upon by an unbalanced force. So to cause a change in its direction (acceleration) a force proportional to its massive weight needs to be applied to it. Now, the elevator is designed to cause a change to the aeroplane AT A SPECIFIC AND DEFINED MASS. If this aeroplane is 100 times heavier then this defined mass, the elevator will NOT apply enough force to cause a change in its direction (acceleration) and it will continue along the straight line with NO INCREASE TO THE LOAD FACTOR. Its the CHANGE in direction, acceleration, that causes the load increase. While its silly to imagine this overweight aeroplane, the physics are still the same when you add or remove normal weights too and from and aeroplane. Its the rate of change in direction that is the issue. The dangerous part about all this is that while we define a VA, it by no means insures full and rapid control deflections wont cause the inertia to reach dangerous levels.

HIC. Thank you for the thread, as you say its a very misunderstood, and under taught subject. Not to put to fine a point on it, but I wonder how long it has been for you? The two most highly used and published texts on BAK over the last 20 years for use in GA are The Trvor thom (ATC) and the Bob tait BAK. To quote Trevors Thom: Chapter 1-6 The primary effect of moving the ailerons is to roll the aeroplane. A secondary or further effect is to cause yaw, since when the aeroplane is banked, the nose will have a tendency to slip sideways INTO the turn. To Quote Bob Taits BAK: page 1.10 Note, The primary response to the application of aileron was roll. However the sidelsip which resulted from the roll produced yaw. In the absence of any other control inputs, the secondary effect of aileron is to produce yaw in the direction of bank. The CPL aerodynamics exam also had " Yaw into the direction of turn" as required knowledge. I also note in Bobs text on the same page " The aircrafts response to the offset airflow is similar to that of a weather cock- infact its sometimes called weathercocking." I just thought I would give the above references for you, so you can see what people who have learned to fly in the last 2 decades have been taught.

Really? Quite an accurate description of the effect. Ive always argued with the theory books, secondary effects of aileron being 'yaw' but in the opposite direction, followed by yaw in the same direction of the turn due to nev's weathercocking effect. All the text books will say 'yaw in the same direction' is the secondary effect of aileron. In most light aircraft this is simply not true. Yes, it does yaw in the same direction, but only AFTER a yaw away from the turn. Any Jab jockey with lazy feet will agree.

:) .... Thank you. So does it mention the stall? Does it single out the Pitch attitude and Axis? Either by Gusts or full defection of controls.. What do you think that statement means? It means a gust OR a full deflection will cause a change TOO rapidly and the deisgn limits can be exceeded. Definition of inertia" a property of matter by which it continues in its existing state of rest or uniform motion in a straight line, unless that state is changed by an external force." A heavier aeroplane will RESIST change better then a light aeroplane will. It CAN NOT be overloaded without a rapid change.

Ok nobody. I'm here;) Answer a few question for me. What is the defintion of VA? Is it only to do with the elevator? Or does it state " full deflection of the controls"? It is not simply a matter if increasing or decreasing stalling speed. I can't stress that enough. If you force a change to the aeroplane in ANY axis too quickly the loads can exceed design limits. It's not Just pitch changes.

Nobody. Yes I understand quite well the principle your using. It doesn't negate the relationship between load factor and acceleration. The reason the wing is being over loaded is due to the load factor being too high yea? How can that load factor be increased by a control input if te aircrafts motion doesn't change? I can assure you, enertia ( acceleration) is required.