Dafydd Llewellyn

I'm a fan of gliders, but I would suggest a modified EMT Emergency Manoeuvers Training in an aerobatic certified aircraft for RAAus INSTRUCTORS at least.. This is NOT aerobatics.... If the instructor is on the ball in other ways I reckon 2 hours flying would cover it and if he/she is already proficient then demonstrate .... Would take about 40 minutes. Be silly to doing any actual flying without ground briefing of a significant nature or you are wasting money. Nev

Yes, that's a good idea. I once pulled a glider up into a stall turn, and the instructor in the back nearly wet his pants! He'd never been in such an attitude! How anybody can instruct without this basic knowledge is beyond me. But this sort of thing should indeed be done in a aerobatic-certificated aircraft, because the speeds in recovery are likely to exceed the flight envelope of a recreational aeroplane.

 

 

Great initiative and should be made a compulsory component of an RA Aus Pilots certificate, and that would not be hard to do. There are plenty of gliding clubs around Australia

That's the way to do it! It would be interesting to hear from the pilots who took advantage of the opportunity.

 

 

The sweeping statement was directly from a flight safety magazine, admittedly a few years ago, but from what I read, the numbers included recreational flying, and were about 84% CFIT. I made the statement in reply to another that suggested most of our incidents are maintenance related.

Well, that's two sweeping statements. Pardon me again, please, if I don't accept either of them. CFIT is a broad-brush handle that really tells us little or nothing about the cause - unless its use is confined to flying into the side of a hill under IFR, which is (in the broadest sense) an error in navigation - and should never occur in an aircraft flown under VFR - so it really should be inapplicable to RAA aircraft (though of course, we know it's not - but 84% sounds just a tad on the high side, don't you think?). Otherwise, a mucked-up forced landing could be described as CFIT. Ever since the process of accident investigation adopted "buckets" like CFIT, UFIT, etc, the accident reports have become practically meaningless. It's an excuse for not doing the job properly, presumably forced upon the relevant authorities by insufficient resources. We don't want to be told what smashed the aeroplane, we want to be told WHY.

I've spent days picking through wreckage, eliminating possible causes, until only one sustainable possibility is left; in one case, a mid-air breakup, what was left was a pea-size hole in the fuselage lower skin, immediately above the end of the engine exhaust, with exhaust residue in the carpet above it. You do NOT find that sort of thing from a report that in effect says, "the Earth got in the way". In that case, the PM did not pick up CO in the blood, because the wasn't any available to sample, and it evidently did not occur to the medico concerned that anything less than a lethal dose of CO might be significant.

 

So you cannot eliminate maintenance-caused accidents by such a wave of the hand; the fact is, we simply do not have the data.

 

There's a way to answer this question, though it's likely to be unpopular - and that is by random sampling of aircraft in the field. You need a team whose job it is to impound a selected aircraft for 24 hours and go over it with a fine-tooth comb, looking for potentially unsafe conditions. This needs to be a very disciplined approach, or it will disintegrate into mere nit-picking; but if it's done correctly, with the owner's participation, the owner - if he has any more brains than a beetle - should be pleased to have such a free survey; and the accumulated defects found will provide an immediate data base for safety improvement. If by chance, it emerges that most aircraft do not have such defects (Ha! - LOL) then the data will show that defective maintenance is not a major issue. This is really very much the same as the GFA annual inspection, except done much faster, by a team - and without going to significant disassembly.

 

You won't get the answer by waving your arms or by making sweeping statements - but I've heard a lot of waffle about safety management systems; if it were up to me, this is one of the places I'd start.

 

 

With over 80% of accidents being CFIT, throughout western world aviation, including recreational, I don't see that we have significant maintenance issues. Of course there's always room for improvement, but it's not how the majority of deaths are occurring, by a long shot.

Pardon me, but how do you know that? I've never found the accident data from RAA sufficiently detailed to make such an assessment. I have some experience in aircraft accident investigation, and I'm sorry to have to say that a lot of the reports I have read have left a great deal to be desired. And it gets really complicated when you get into areas like "design-induced pilot error" or cases where the engine fails and the pilot makes a mess of the forced landing. Is that bad training (was not taught how to judge the approach to a sloping landing site); Pilot error (should not have been flying over un-landable terrain); Pilot error (fuel management - how do you tell if the fuel system leaked as a result of landing); maintenance error (left a split-pin out of the throttle linkage, or something of the sort) etcetera, etcetera, ad nauseum. Almost all accidents have multiple causes; sorting them out into a correct order of precedence is extremely difficult to do.

Therefore I distrust sweeping statement like the above. I don't think the data are good enough to make such a statement.

 

Aside from that, take a good look at the GFA maintenance system. It deals with factory-built products that can be used to earn a dollar, and it's done mostly by voluntary labour. No, it's not perfect - but it's pretty good, judging by the results. Gliders have certificates of airworthiness, and annually-issued maintenance releases. It can be done in the context of a recreational aviation activity. The RAA system is a shambles by comparison.

 

 

I did my PPL training back in the mid-60s and I must say Dafydd that in all the years since then, yesterday is the first time I have heard of "wind axes".We live and learn.

Yes, well you would have done pretty much the same theory course that I did in 1962 (a vastly better one than what is served up to-day, from what I can see); however those courses are always somewhat simplicated to make them a bit easier for people who are aiming for a career as airmen. I was doing aero engineering at Sydney Uni at that time, and we got wind axes rubbed into us. I'm glad I do not have to pass a modern theory course, because it's so full of those sorts of half-truths that I'd never pass; you have to give the answer the course setter expects, and it's all "multiple-guess" choices, and my choice is almost always "none of the above". Back in '62, it was essay-type answers, not multiple-choice; and you got marked on your understanding of the subject. It's academic to the subject matter of that thread, as you pointed out. Not so academic if you are doing developmental flight testing, and trying to analyse what's wrong with the aircraft, however.

 

 

Further to the aircraft axes discussion ...http://www.flightlab.net/Flightlab.net/Download_Course_Notes_files/1_ AxesDerivatives.pdf

Thank you. About bloody time!

 

 

Dazza, I don't see a funny, I only see an informative..............Maj...

Truth is the daughter of time. The truth hasn't yet emerged - but it will.

Apart from that, isn't this thread getting rather a long way off subject?

 

 

Ok.. Well straight after that once you have control (seconds) roll the wings where you need them .Aileron neutral till then. Nev

Yes - and if it happens to be on its back, roll it out, don't pull it through.

 

 

Pity you didn't bring that up earlier Dafydd. It's what it is all about. If you move the stick forward a distance to an appropriate position, and apply full power you will be out of the stall straight away, ( then get the attitude right and take it from there).. Unload the wing it is. You can almost "punch" the plane out of the stall. With gliders the long wingspan is there to contend with as an extra factor. The main thing it you are in a stall "situation" is to regain control "ability" and keep maximum height between you and the ground. The " normally taught" stall recovery uses hundred of feet of height. You obviously don't always have it. Nev

Pity you didn't bring that up earlier Dafydd. It's what it is all about. If you move the stick forward a distance to an appropriate position, and apply full power you will be out of the stall straight away, ( then get the attitude right and take it from there).. Unload the wing it is. You can almost "punch" the plane out of the stall. With gliders the long wingspan is there to contend with as an extra factor. The main thing it you are in a stall "situation" is to regain control "ability" and keep maximum height between you and the ground. The " normally taught" stall recovery uses hundred of feet of height. You obviously don't always have it. Nev

Yes, well, that's the way it should be taught. The only difference in the spin, is that you need to get opposite rudder in FIRST. But unless it's in autorotation, "punch" it out. Good description.

 

 

avayner - the gliding suggestion is a good one. I went gliding for exactly this reason. The only downside is the danger of acquiring another expensive hobby.dodo

Agree emphatically. Glider pilots fly almost continually on the edge of a spin whilst thermalling, and it's not uncommon for the thing to start the beginnings of autorotation, in a turbulent thermal; but one gets so accustomed to it that you correct with a minute stick motion, and the passenger does not even notice. Very like keeping a pushbike upright, actually; you learn to do it as an unconscious reflex action. Once you have acquired this you are virtually "spin-proof", apart from the instances like the inadvertent flick roll, or spin off a cable break whilst winch-launching, where there is no "incipient" phase - the aircraft goes straight into a fully-developed spin. Those instances are dealt with by learning to "unload the wing" - i.e. shove the stick forward to zero G. Did you know it's impossible to stall an aircraft at zero G? I've never understood why this is not taught as part of the normal syllabus. You never hear an instructor use the words "unload the wing", do you? (Maybe they do when teaching aerobatics, but you can do this in any aeroplane without overloading it - provided you don't maintain it too long!

 

 

I used the words "quite different" not "liberal".

Fair enough; however in view of the source - FAR 21.173 - I would suggest they are really not very different at all.

 

 

LSA and Sport Pilot rules in the USA are quite different from here. Old, existing aircraft can be reclassified LSA. LSAs can be aerobatic. Might be tough to fit a new aerobatic aeroplane within the weight limit but only because people choose creature comforts and more power.Even a new Champ only comes with a big engine and is really only a single seater, certified as an LSA and spinnable.

Sport pilot instructors are required to undergo spin training, same as GA instructors.

 

My backup plan for if/when I get tired of CASA is to get my fix in the USA with a Clipped Wing Cub doing aeros on a sport pilot licence.

That's interesting; CASR Part 21 Subpart H says:

21.172 Definitions for Subpart

 

In this Subpart:

 

LSA standards means:

 

(a) the standards for the design, performance or continuing airworthiness of light sport aircraft issued by the American Society for Testing and Materials, as in force from time to time; or

 

(b) any other standards, for the design, performance or continuing airworthiness of light sport aircraft, the use of which is approved by CASA.

 

Note 1 Advisory Circular 21‑42 lists the LSA standards.

 

Note 2 The standards issued by the American Society for Testing and Materials may be found in www. astm.com.

 

qualified manufacturer of a light sport aircraft means:

 

(a) a manufacturer who, at the time the light sport aircraft was manufactured, held a current production certificate for an aircraft; or

 

(b) a manufacturer who has made a written declaration that, at the time the light sport aircraft was manufactured, it had:

 

(i) contracted engineering personnel with experience in ultralight or light aircraft design to ensure compliance with LSA standards referred to in paragraph 21.186 (2) (b); and

 

(ii) facilities and tools suitable for the production of the aircraft in accordance with the applicable LSA standards; and

 

(iii) competent personnel, with appropriate training, skills and experience, to perform work that affects product quality.

 

21.173 Eligibility

 

(1) An aircraft registration holder, or the owner of an aircraft that is registered with a sport aviation body, is eligible to apply to CASA or an authorised person for a certificate of airworthiness for the aircraft.

 

Note For the meaning of sport aviation body, see subregulation 2 (1) of CAR.

 

(3) In this regulation:

 

certificate of airworthiness does not include a provisional certificate of airworthiness or an experimental certificate.

 

Source FARs section 21.173 modified.

 

In other words, the Australian requirement is based on the American requirement, with some modifications. To my understanding, the principal modifications are:

 

(i) The Australian version allows other design standards if the Applicant wishes to use them and CASA considers them suitable (in other words, one can have bargaining session with CASA over the details of the design standard, or one can simply accept the ASTM standard;

 

(ii) The Australian standard allows the 45 kts stall speed to be in the landing configuration, rather than in the cruise configuration.

 

Thus, the Australian requirement if anything, allows more scope. Further, if you read 21.186, you will see that it allows automatic acceptance of foreign LSA aircraft.

 

So exactly how is the American one more liberal?

 

 

So the C150 was obviously certified for spins in the utility category and I take it our 600Kg weight limit snookers us again .....

Yes, if you look up FAA TCDS 3A19, they were indeed utility category. The model 150 A, -B, and -C were 1500 lbs (680 Kg) and the -D,-E-and -F were 1600 lbs (726 Kg).

 

 

Ah, I knew this one would raise its ugly head. Paperwork was complete on this one, but it was allegably falsified by the importer, and seller of the aircraft. New logbooks were alleged to have been created conceling a past history of the aircraft. This previous history of the aircraft was alleged to be conceled during the Australian registration process by the importer.Please tell me how the RAAus is supposed to check on this info when it is not revealed in the first place. Surely you do not expect the RAA to search all over Europe for this information, every time an aircraft is imported from Europe ?..................Maj....

I would offer the observation that, had the aircraft been required to have a C of A, the falsification of the data would have almost certainly come to light, because the aircraft would have to come into Australia on an export C of A. Because the RAA system lack a C of A process, the acceptance of the aircraft by RAA for registration is the de facto substitute of the C of A; the purchaser has no other authoritative document on which he can rely. Therefore, the RAA system is deficient. It purports to supply more or less equivalent safety to the CASA system, but in fact it fails miserably to do so. The current registration debacle is ample evidence that CASA thinks this is the case.

The RAA system allowed unscrupulous importers to rort the system for at least a decade. The current mess is the consequence.

 

 

I agree Dafydd,The problem lies in spin training NOT being mandated anymore and that is a sad state of affairs. If spin training was mandated, then manufacturers would have to make spinnable trainers.

I understand the need for increased strength in 'aerobatic' or 'utility' category for aircarft ...BUT a trainer does NOT need to be 'aerobatic' category to be spinnable. All the C150s were spinnable and the Aerobat was the only 'Aerobatic' version. So what was wrong with the basic C150 as a style of trainer, they were bloody near bullet proof, still operating and some are 40 years old plus. Why Cessna gave up on the 162 in the spinning category is beyond me; they went through the whole process and cost and then gave up on certifying them spinnable. The C162 could have been the perfect spinnable ultralight/LSA trainer.

This comes down to the definition of the permissible manoeuvres for each certification category; here is the definition from FAR Part 23:

§ 23.3 Airplane categories.

 

(a) The normal category is limited to airplanes that have a seating configuration, excluding pilot seats, of nine or less, a maximum certificated takeoff weight of 12,500 pounds or less, and intended for nonacrobatic operation. Nonacrobatic operation includes:

 

(1) Any maneuver incident to normal flying;

 

(2) Stalls (except whip stalls); and

 

(3) Lazy eights, chandelles, and steep turns, in which the angle of bank is not more than 60 degrees.

 

(b) The utility category is limited to airplanes that have a seating configuration, excluding pilot seats, of nine or less, a maximum certificated takeoff weight of 12,500 pounds or less, and intended for limited acrobatic operation. Airplanes certificated in the utility category may be used in any of the operations covered under paragraph (a) of this section and in limited acrobatic operations. Limited acrobatic operation includes:

 

(1) Spins (if approved for the particular type of airplane); and

 

(2) Lazy eights, chandelles, and steep turns, or similar maneuvers, in which the angle of bank is more than 60 degrees but not more than 90 degrees.

 

© The acrobatic category is limited to airplanes that have a seating configuration, excluding pilot seats, of nine or less, a maximum certificated takeoff weight of 12,500 pounds or less, and intended for use without restrictions, other than those shown to be necessary as a result of required flight tests.

 

So, to be allowed spinning, under FAR Part 23, the aircraft needs at least Utility category. That's only available at the level of FAR part 23 certification (the Euro CS 23 is identical). This requires the positive limit load factor to be 4.4, instead of 3.8 - i.e. approximately 16% increase.

 

This means that VA increases, and hence the minimum allowable value of VC increases; and VD must be not less than 1.5 VC, rather than 1.4 VC for normal category. So the gust load factors increase will increase probably somewhat more than the manoeuvre load factor.

 

Aerobatics take the life out of the structure at about ten times the rate of normal flying; so for a similar life, the 1G stress level must be roughly half that of a normal category aircraft. So the structure weight of the fatigue-critical structure will more than double. Overall, the structure weight may increase perhaps 30%. That means the MTOW has to increase, and it's a snowballing process, because the engine has to get bigger, it needs more fuel, etc. A DHC-1 had an MTOW around 1700 lbs, as I recall, and it had almost zero baggage capacity. It was not exactly structurally inefficient; carbon fibre etc would get that down a bit, but it still won't fit the existing categories; the book will have to be re-written. There is simply no way to avoid a significant increase in MTOW, unless you accept a short fatigue life; and that means the current recreational aircraft weight limits are a straight-jacket.

 

Imagine the scream from the 95.10 brigade!

 

If you look at the requirements for spinning in PA 28s etc, it was always at a reduced weight and a restricted CG range; the aircraft had dual certification - normal category at one weight, utility category at a reduced weight - but people had their heads in the sand about fatigue life in those days.

 

To make this happen, essentially means re-inventing the aeroplane, not the recreational aeroplane. Or else, make them from wood, which does not fatigue.

 

 

I was lucky enough to do spin entry and recovery in C150s and later aerobatic training in the Citabria with fully developed in-spin and out spin aileron applications, the behaviour of the aircraft being notably different. I confess to having a somewhat 'ho hum' attitude toward spinning until Uncle David (DJPacro) encouraged me to read up on the subject matter and providing me with some very interesting material. He showed me the risks inherent in spinning. His knowledge on aircraft behavior modes in aerobatic manoeuvrings is exceptional.Interesting that Cessna certify all C150s, C152s and C172s for spinning, but not the C182, C180, C185 or C206 and notably and to my absolute surprise NOT the C162 Skycatcher which in my view is a huge design mistake. For those of you that do not know, Cessna wrote off the two test C162s when putting them through the spin mode testing, the test pilot bailed in the first case when the ballistic chute failed, and in the second case the chute operated but the aircarft was written off when it was dragged to destruction by the ballistic chute on the ground.

 

There are dozens if C150/152s out there that could readily operate in spin training, the more important question is perhaps are there any instructors left who are competent in training students? Apart from spin behaviour risks a properly spin certified aircraft can virtually only be damaged by poor recovery techniques(read over speed) not from the spin manoeuvrings itself where the aircraft remains in the stalled one G state.

 

I must admit that I have always considered the one to one 1/2 rotations of an incipient spin in our typical aircraft as harmless, but Dafydd has just put the wind up me. That is a bloody shame because incipient spin training should absolutely be taught.

 

So what can be done about it Dafydd? Is it just simply too expensive to get an aircarft certified to be safe in the incipient spin (1 or two rotations before a fully developed spin)? So if I understand you correctly you are saying that the one turn certification is not worth anything and in some circumstances such a manoeuvre is down right dangerous?

David, to get some perspective on this subject, I suggest you download and read the relevant portion of FAA AC 23.8C (in particular, the section on 23.221). In part, it says:

(1) Objective. The basic objective of normal category spin testing is to assure that

 

the airplane will not become uncontrollable within one turn (or three seconds, whichever takes

 

longer) if a spin should be encountered inadvertently and that recovery can be effected without

 

exceeding the airplane design limitations. Type certification testing requires recovery capability

 

from a one-turn spin while operating limitations prohibit intentional spins. This one-turn

 

"margin of safety" is designed to provide adequate controllability when recovery from a stall is

 

delayed. Section 23.221(a) does not require investigation of the controllability in a true spinning

 

condition for a normal category airplane. Essentially, the test is a check of the controllability in

 

a delayed recovery from a stall.

 

In other words, the so-called "one-turn spin" is really not a test of the aircraft's spinning behaviour; it is, rather, a test to ensure that a fouled-up stall recovery does not develop into an unrecoverable spin or whatever, within one turn. Booting full rudder - possibly with in-spin aileron - is pushing that definition a bit far - and given that one turn commonly occurs in not much more than two seconds, using it as the basis for doing incipient spins is cutting the safety margin awfully fine.

 

The answer? Well, in the short term, go visit your local gliding club. In the longer term, we need to create a market for a truly spinnable trainer. As things stand, manufacturers can see no market for such a device - because to make a good trainer, the aeroplane loses some other, more marketable attributes. It has to have a higher empty weight, for a start, because aerobatic category demands a higher Vne, and that means larger design gust loads; also it has to be designed for at least 6G, not 4G; both of which mean that a larger % of the total weight has to be structure. It's likely to require a fatigue analysis, because aerobatic usage is hard on airframe structures. Both these things need a revision to the existing design standards for recreational aircraft, none of which cater for aerobatic category, and all of which severely penalise additional structure weight.

 

The fact is, that a good trainer and a good working aeroplane are diametrically opposite concepts; the primary mission for a trainer, is for the pilot to learn to fly the aircraft. The primary mission for a working aircraft, is for the pilot to fly the mission, whatever it may be, with minimal preoccupation with the mechanics of flying the aeroplane. Thus a good trainer tends to be a high workload machine (at least to fly with some polish), whereas a good working aeroplane should almost fly itself, with the pilot merely telling it where he wants it to go. Manufacturers do not generally recognise this; they try to produce a product with as wide a customer appeal as possible, with the result that it generally does not do anything particularly well. The debate about "lazy feet" is an indicator of this; a good trainer will not allow the pilot to have lazy feet; a good working aeroplane simply does not care.

 

The Chipmunk was a good trainer; it was specified to be so by a military requirement. It's almost useless for any other purpose. It was a tail-dragger with a free-castering tailwheel, and the only means of steering it at taxi speeds on the ground was via the brakes - which worked from the rudder bar, if you pulled the brake lever about half way on. My first exposure to flying was for the instructor to taxi clear of the parked aircraft, then hand over to me and indicate a point on the opposite side of the airfield, to which I was supposed to taxi the thing. Several 360 degree turns later, with a profane silence from the back seat, I started to get it together, and by the time we reached the designated point, I had been permanently cured of "lazy feet". By contrast, a Maule (also a tail-dragger) has a rudder tab driven by the aileron circuit, and a steerable tailwheel, and you can fly it around the sky with both feet flat on the floor, with almost no slip or skid; so you can fly it very much as you drive a car, which is great if you are flying for a purpose like shark spotting, or fire watch, where you need to keep your eyes outside. Each type has its uses; but the marketplace does not understand this in quite these terms; and therefore, neither do the manufacturers, and nor do the various authorities that specify the requirements for our training schools. Mostly, what we get is neither fish nor fowl.

 

The Chipmunk requires constant attention from its pilot; the Maule is far less demanding - but it can still spin. So aircraft of both styles are needed. But we won't get good trainers until the requirement for them is understood and their use is made mandatory for pilot training, because unless there is sufficient demand for them, the manufacturers won't build them. You want supply, you gotta have demand.

 

 

I know of one C-150 that the fin and rudder bent over but did not break off. It happened at Port Macquarie NSW. I believe the plane went into a spiral and the higher airspeed enabled the rudder/fin to fail. I think the student held full rudder on. This would apply much more load that a normal spin would. While the DHC-1 Chipmunk was cleared for spin training, by the DCA after an inquiry , I personally don't believe with the normal sized rudder that It was entirely predictable in the recovery and that there was pressure to keep them on line.As Dafydd says there were no available aircraft in the mid 60'd and spin training was not incorporated in the PPL or any other syllabus. I have always regarded this as a mistake. Aircraft like the Whitney Boomerang if it hasn't , could be spin certified. the "STUPID" raked back tails are just a design styling exercise and if you have any idea where the relative airflow is coming from during a spin and how the rudder is blanketed on some designs, you would wonder why the design is permitted. Nev

You are correct about the Chipmunk; I later learned that my boss in DCA, John Thorpe, had personally spin-tested every DHC-1 on the Australian register, as part of that DCA investigation. We were taught to make the final part of pushing the stick forward, with the whole of the hand behind the stick, because the thickness of your fingers, between the stick and the panel, was sufficient to prevent recovery from a flat spin. As the recovery started and the nose started coming down, the rate of rotation increased initially, which could be very disconcerting if you were not warned about it. However, a whole generation of pilots survived spin training in them.

Spinning was part of the PPL syllabus in 1963, when I did my training; it was dropped about two years later, which I always thought was an unfortunate decision, to say the least. The most beautifully-behaved aircraft I have spun was the L-13 Blanik; it was absolutely predictable; I did hundreds of spins in them as a gliding instructor; you could recover on a pre-selected heading with no difficulty at all. However, the Blanik has a vertical tail that you could market as advertising space.

 

 

Used for .Fuel level,not fuel flow

Ha- why didn't you say so?

 

 

No - not quite right as I understand it. Directional stability is the stability associated with the aircraft wanting to return to its direction of travel. That might require it to return there by a pitch change or a yaw change (or both) according to whether the upset or disturbance has changed the direction that the aircraft is pointing in its x axis or its y axis (or both).In other words if the aircraft is pointing where it is heading (z axis) and then gets upset by turbulence (say) such that the nose rises (y axis) and the nose then seeks to return so as to point in the direction of travel, then the aircraft has positive pitch directional stability. Similarly if the aircraft is upset such that the nose moves to either side of the direction of travel (x axis) and the nose then seeks to return so as to point in the direction of travel, then the aircraft has positive yaw directional stability.

 

I should not have put the word longitudinal in parenthesis, it confused the issue because 'longitudinal' stability is pitch and yaw directional stability combined, otherwise, by your reasoning we would have lateral stability for roll, longitudinal stability for pitch, and vertical stability for ... what ... yaw? Because the three axes are lateral, longitudinal and vertical - not lateral, longitudinal and directional.

Nope. Aircraft stability is usually defined in relation to "wind axes" - not axes fixed in space relative to the Earth. See http://en.wikipedia.org/wiki/Aircraft_principal_axes

 

 

I think you will find that the fuel flow rate in your aircraft is too small to show with those pellets, the way it does in a bowser. However, I have successfully used a Rotameter - See http://en.wikipedia.org/wiki/Rotameter to measure in-flight fuel flows; I made a suitable one with a piece of 25 mm Perspex rod, a tapered reamer (one of the devices sold by Radio Spares etc as a tapered chassis reamer will serve) and a 1/8 inch countersunk-head aluminium rivet. I reamed the hole so that the rivet could just drop right through without jamming, and used some wire mesh (about 1 mm holes) at each end to stop the rivet from escaping. I tapped each end of the piece of Perspex rod to accept a brass hose barb, and soldered the mesh to the threaded end of the barb. I positioned this vertically with the rivet head uppermost, so the flow lifted the rivet.

 

The bore of the perspex after reaming looked opaque - but that disappeared when it was wet with fuel.

 

Of course, if you locate this where you can readily read it, this probably means you will have exposed fuel-system components in the cockpit - not a smart idea; also it's a modification to the fuel system, so it needs formal approval if it's in a certificated aircraft. This is probably the reason you do not normally find this sort of hardware in aircraft.

 

 

220km/hr is only 118kts.So some numbers follow...

Scott Winton Opel; 40hp = 280 kmh (151kts)

 

Verhees Delta; 50hp = 220 kmh (118kts)

 

Arnold AR-5; 62hp = 213 mph (185kts)

 

[ATTACH=full]23577[/ATTACH]

 

The Arnold AR-5 was powered by a Rotax 532, then later a 582, and weighed less than 300kg!

 

Have a look at; http://www.ar-5.com/kitcarm93.html

And where are the Position Error calibration figures? (See http://www.casa.gov.au/wcmswr/_assets/main/rules/1998casr/021/021c40.pdf

 

 

I plead guilty to thread drift but my favourite subject, sorry.I am only aware of one instance (in the UK) of fin failure of a 150 and was not related to spinning.

Early examples, before the Aerobat, had a smaller vertical tail and apparently some spin issues.

 

There is an FAA Safety Bulletin on spinning Cessnas circa 1974.

 

My opinion, from talking to a few people who scared themselves in 150/152s is that many people did spin training in them without really getting into a fully developed spin - then the first time they let one wind up, perhaps with some aileron to flatten it they get a very nasty surprise. I have a poor opinion of the standard of spin training done in some places at some times.

 

I was friend/student of HKM and RCD so got all the Victa guff. Owned an A/T 100 myslf. I also did some model spin tests of the CT-4 which reproduced its steep (somewhat similar to the Airtourer) and flat spin modes ....

Yes, well, since the subject came up, I thought it needed an airing.

 

 

I disagree, Dafydd. The Cessna 150 and 152 spin nicely and will stay in a stable spin. The 152 not so ready to enter, however. Both can go flat with some inspin aileron. (references available, not just my opinion)And "the last truly spinnable trainers"? Citabria and Decathlon are classic spin trainers. Pitts S-2A?

 

CT-4 is a different story.

 

I agree about the 162 and TP1076 etc. I read somewhere that Bihrle Applied Research got involved to help fix it. I'm currently in the USA so will give my friends there a call (I expect I may not be able to repeat here what I may be told, but off topic so perhaps a new thread for that).

You are quite correct, the Citabria (read it backwards) and the Decathlon are fully spin-certificated aircraft. However they were not - unfortunately - generally available around the time spinning was dropped from the PPL syllabus. A "straight-tail" Cessna 150 will - by all accounts- spin; but the vertical tail is prone to snap off, which can spoil your day. The Pitts S-2A also was not around back then - and I'm not sure its seen as a trainer, to most people's thinking.

I've not tried a 152; however the version sold as "aerobatic" caused some excitement; every once in a while, somebody manages to get it into a spin mode that is much more difficult to recover from. I had the job, as a junior airworthiness engineer in DCA, of measuring its moments of inertia in pitch, roll and yaw (these are critical to spin recovery, as is the vertical tail). According to the British military airworthiness requirement, AP 208, its vertical tail is completely blanketted in a spin, so the recovery relies on elevator authority only - and a very small increase in the pitch moment of inertia can make a large difference. We were not allowed to complete the investigation, by our political masters, a situation that completely horrified me.

 

The Victa airtourer, in its original form, had difficulty recovering from a spin; as a result, by the time it was certificated, it had less aft CG travel, less up-elevator travel, more rudder travel, and it had grown the odd "blade" arrangement underneathe the elevator, that fills the gap between the elevator and the extended rear fuselage fairing. As a consequence, whilst it will perform an enthusiastic incipient spin, it falls out of autorotation after about one and a half turns. If one holds in-spin controls, the process repeats itself ad nauseum - so it's a form of oscillatory behaviour, it never settles into a true spin. It serves the training purpose, to a degree. I've not tried spinning a CT-4; I do not know what changes the Kiwis made to it in that department.

 

 

thanks for the input there mate, that was very helpful. I certainly agree about the gliding thing, I am a glider pilot myself and the training reinforced by GFA is what has had me so shocked regarding RA AUS.I think I should make it clear hear to everyone however, What I am refering to is in actual fact the incipient spin, not a developed spin, I would never put any aircraft into a full spin without knowing every nitty gritty detail regarding this aircraft and spinning first. Im certainly no Chuck Yeager and am not wanting to be pushing envolopes. I must say however the information you provided regarding the VG's was most interesting. regarding there difficulty going into a spin installed was certainly a consideration I had looked into and clearly found appealing. No one has ever mentioned however there difficulties in recovering from one.

 

I do however find your comments regarding the drifter and spins interesting. by no means am I saying there wrong. I by know means will pretend to have the knowledge to be able to comment in either direction with any form of confidence. Though as mentioned earlier, I was put through spin training in the drifters, and seen many others do it to. I just would have presumed that would have ment the aircraft (certified drifter) must have been certified for it. Also I know that Austflight did quite alot of spin testing on the aircraft, as I think HITC may be able to vouch for. Weather it was then certified for it I guess is another story! referencing back to my training however, while doing a couple of recovery's from very early stages of a developed spin (which while possibly not certified to do so, both the instructor and I, a far better educated student walked away from unharmed), 98 percent of the training was only incipient.

 

So I guess this brings us back to the base question is it legal to practice an INCIPIENT spin in RA outside of being under instruction.

Yes, I understand that you are talking about incipient spins. The fact that AUF and RAA (and GA) instructors have been forced to do that sort of thing in aircraft that were never certificated for it, is, as far as I am aware, a case of authority turning a blind eye; the fact that all normal-category certificated aircraft are subject to the one-turn requirement seems to be the basis for this - but it's still a contradiction of the design requirement. The omission of any form of spinning clearance - even the one-turn spin requirement - from CAO 101.55 and BCAR S initial issue (and CAO 95.25) were cases of criminal negligence, to my way of thinking; this seemed to be an international insanity at the time. Austflight took advantage of it and refused to spin-test the Drifter. Jabiru and Skyfox were a bit more responsible. I do not know the position for Thrusters or Quicksilvers, etc. It has since been corrected in BCAR S issue 2, and is not omitted in the ASTM standard for LSA. However some of the Eastern European ultralights that pre-date LSA may not have been spin-tested; and of course un-certificated kit aircraft are anybody's guess. The first Smythe Sidewinder in Australia killed three people that way. Yet one can obtain a licence in a homebuilt if one has built it one's self; it is obvious that very few instructors understand the risks they run in doing any form of spin training in such aircraft.

Spin training was written into the original AUF syllabus by Bill Dinsmore, who intended that it should be done in gliders until/unless a spin - certificated trainer became available; however it was removed by Rod Birrell in his first term as AUF president. Spinning was also eliminated from the GA PPL syllabus in about 1965 or so, because there were no spinnable trainers still in production. The fact is that spinning is a natural behaviour of fixed-wing aircraft, and whilst we can make them less eager to fall into one, it cannot really be altogether prevented - tho the original Ercoupe tried pretty hard to do so. Styling features such as swept-back vertical tails have proliferated as a result of the deletion of spinning from the syllabus, but they are adverse to spin recovery, as Cessna re-discovered with the prototype 162 (They cannot have read NASA Technical Paper 1076 - available on the internet - or maybe the styling dept. overruled engineering) . The whole situation is slightly insane, actually; however the GFA remains refreshingly realistic about it.

 

So we still have stall/spin accidents, and we will continue to do so until this idiotic situation is corrected.

 

 

I think the Jabiru went through the full spin test - and failed. I heard a similar story of about 100 spin tests, two of which were unrecoverable, requiring use of the spin chute. That's why they come with a placard "no intentional spins".Again, that means a developed spin, an incipient spin is OK.

But - be careful. Legal is good, safe and legal is better.

 

dodo

Wrong. The original Jabiru was spin tested for the one-turn case, and passed. I know, because I did the flying. Jabiru did this voluntarily, it was not a requirement under CAO 101.55 at that time. ALL non-aerobatic certificated aeroplanes are required to be placarded "No intentional spins" - this does NOT mean they were not tested. ALL Jabiru models have in fact been spin tested for the one-turn case; some of them required increased vertical tails to pass - and they got them. Most of this testing was done by Keith Engelsman.