carlsnilsson

G'day Keith: that's most kind. Q. Do you have a paper book copy or CD? If the former, I am presuming there is a procedure for removing and replacing the horizontal tailplane. If you have a scanner, perhaps you could scan those pages and upload a file or zip it and email me PM (not quite sure how to do that, but I guess the procedure is explained by the webmaster somewhere on this board - my son tells me it is bad practice to publicly post an email address). I'll look tomorrow. Alternatively, if no scanner, I should be able to PM you my postal address and ask you to copy pages and post. Of course, if there is nothing in the manual about removing the tailplane, we can forget it and I'll just follow my normal procedure of simply winging it. It's not exactly complicated - i just thought it would make a nice change for me to read what i'm meant to do before I go ahead and do things in the wrong order. (Removing the carbies from the 912 is one such example - there's the right way and several wrong ways of going about it!) On the other hand entirely, if you have it on CD, we should talk some more! I'm talking about the maintenance manual for the aeroplane, not the 912. Regards Carl

G'day Wigg: In note above where, nearly five years ago, you offered to post a CD copy of the Skyfox (CA22 or 25) maintenance manual to someone in need. I have a CA22 taildragger Ser. no. 22027 Reg. 55-0688 for which a copy would be most useful. Is your kind offer still open? I would quite happy to make a modest payment for your costs plus post - maybe could use Paypal if you have an account or whatever. I fly out of Cambridge, Hobart. Regards Carl

.That's good advice. You can get pretty compact emergency parachutes that open smartly. Glider pilots sometimes have them. Use as a cushion - either for the back or the bum. Carl

Firstly, it takes a pretty good crack to bend that spar. When I pushed mine (backwards) through hitting a tree, the shear force tore the mounting of an internal diagonal drag brace and showed that shear by tearing the fabric above the fuel tank. The innermost bay with the tank has no drag brace and hence can be more easily distorted in shear - the tank taking some of the distortion. My front wing mount bracket (the short vertical tube into which the clevis pin goes) was also bent, as was the pin itself. I managed to straighten the bracket tube, after checking that the weld was not damaged, although I spent a couple of days doing it rather carefully. In your case, it rather sounds as if the frame tube took up the distortion. If it is not kinked, then it likely could be straightened. As for the spar, all may not be lost. If you decide to go ahead with repair, get into contact with foxworker. He has some good contacts in prime Fox country (SE Queensland). Regards Carl

G'day Mike: Either my brain (?) has gone to sleep or I'm not familiar with the "TG" in CA25TG. I presume that's a taildragger CA25 -yes? If all the aileron hangars snapped and the wing struts ruptured, it would seem that the left wing took a pretty severe impact. Did the fabric tear above the fuel tank in the bay nearest the fuselage - that would indicate a fair amount of shear on the wing which may have bent the spars - or at least the front spar. Also, take a look at the wing attachment points. On the other hand, I have a friend with a Fox that hit power lines on final approach and nose-dived into the ground. He and his wings were undamaged, although the fuselage needed some repair. It flies beautifully today. Carl

John: I'd be surprised if anyone could answer your question authoritatively. There has not been any AD or AN re wear on these bushes, to the best of my knowledge. Certainly a number of Foxes have done lots more hours - some up around the 5000 hour mark, I believe. There are probably quite a few which have done 3999.9 hours! However, I would use my own judgement, based on the following:- firstly, can you rattle the whole aileron on the ground inside those bushes? Flutter would probably be more easily induced by a change of aileron angle of attack rather than a minute wobbling of position. (I'm speculating, but this would be my thinking). Flutter is an oscillation, so you have to have at least two opposing forces. When an aileron is out of balance, the moment of inertia changes (probably increases). Flutter occurs when wing/aileron distortion (i.e. elasticity of the system, which may have several components) opposes the air pressure distribution which is distorting the system. In addition, some important part of the wing/aileron structure needs to have a resonant frequency in tune with, say, the fluctuating control surface. "Out-of-balance" for the ailerons is an important factor because it effects the moment of inertia which determines the natural frequency. If you ever felt a vibration of the ailerons that came and went, for example, that would be a warning sign not to be ignored. Now, Daffyd Llewellyn, when testing, found that he could sometimes induce flutter in the Fox ailerons (I can't remember whether they were one piece or segmented, but I can check) at speeds as low as 65 kn IAS by giving the stick a sideways rabbit punch. If you are worried about your ailerons, try that! Try it first at low speed, say 60 kn with a very modest sideways knock. If nothing results, increase the force of the sideways knock a little. A small step at a time is the watch phrase of a test pilot! On one occasion instructor Tony Curzon discovered that he could induce some modest flutter at cruising IAS in a friend's Fox and immediately reduced speed (the correct thing to do) and promptly landed. The torque tube bushes through the fuselage were pretty loose so they did something about that and the effect went away, so I am told. I have given my stick the sideways knock test at 70 kn with no effect. That's good enough for me. "If it ain't broke, don't fix it" might be applicable here with regard to the hanger bushes. The point about the sideways knock is that it generates a sudden force. That is, the suddenness - the short rise time - incites a range of frequencies, unlike a gradual push. The range of frequencies might be enough to excite some resonance in the system. That would be a warning and that, I think, would be what an aeronautical engineer might suggest in order to answer your question. Regards Carl

John: Remember, this is a flexible wing. The original ailerons before certification were one piece. When loaded in flight, the wing bends enough such that the original one-piece ailerons jammed solid. That's what Llewellyn was testing. That's why the ailerons are now segmented. The wings still bend in flight and so does the full length of aileron. Play when the wing is unloaded on the ground does not necessarily mean play in flight. I suspect that you need some degree of clearance in those bushes to prevent binding in flight. So long as the bushes are still in one piece, I don't think I would worry about it, unless the aileron as a whole rattles around. The wings can flex inches in flight. I think the one bush you should pay attention to is the one that constrains the torque tube where it emerges from the fuselage/turtle deck, based on the experience of my friend Tony Curzon who once suffered aileron flutter. I'm not an expert in this matter. Few people are. Llewellyn is. Carl