Oscar

Andy - best news for some time!. absolutely - get the specification right before committing to ANY development!.

 

 

Andy, the call has been on for the development of an integrated business process management system based on a whole-of-enterprise, web-enabled relational database structure that would remove a vast amount of the routine transaction processing load from the staff, for at least a year or more. I am sure that you have a very good understanding of what that entails - including the fact that it cannot be accomplished by piecemeal system development but MUST be done according to an overarching IT development strategy so that all 'modules' integrate seamlessly, utilising one master data field definition structure - not something that is cobbled together post-hoc from individual modules gathered from disparate sources a la Peoplesoft.

 

People need to remember that RAA exists to be an interest-group-centric agent of CASA (which is, for better or worse, the authority that has been mandated by legislation with the authority and responsibility for aviation safety in Australia). It enjoys monopoly status for certain classes of aircraft entirely due to CASA accepting that monopoly status - but please note that CASA has stated that it is not bound to eternally continue to support a monopoly should that be found to be ineffective in exercising the delegation it has from CASA for its operations.

 

The idea that RAA is a 'club' - a 'band of siblings' - united in a common love for all things that the RAA seeks to be, is comprehensively dismissed by the low voter turn-out for Board representation. I don't have the interest to do the numbers, but I suspect that an audit of the total number of members who voted for every position currently occupied on the Board would be somewhere of the order of 25% - 33% of the total membership? Perhaps someone else can tally up the numbers, but I think it would be found that more than half of the 'membership' of RAA have basically no interest in RAA per se - they would subscribe to any service provider that allows them to fly legally and safely in their small aircraft. Should CASA endorse a 'competitive' commercial service that meets that basic requirement at a lower cost than RAA, it is reasonable to postulate that membership might well hemorrhage .

 

Fanciful? I suggest you contemplate on the idea that CASA might - just might - revise its maintenance authorisation requirements such that a suitably-trained and 'qualified' RPL-qualifying aircraft owner could do her/his own basic maintenance on her/his RPL-qualifying aircraft. What's your best guess as to how many defectors from RAA would happily hang letters on their aircraft if that makes a practical reduction in the administrative cost of their flying?

 

RAA HAS to be a 'service' first and foremost and an 'organisation', secondarily. I should add that I whole-heartedly endorse the role of RAA as an advocate for small-aircraft operation, which needs an advocate in such areas as support for the maintenance of regional airfields, access to airspace, promotion of the wider social acceptability of RAA-class operations etc. However, those are 'value-added' components for RAA membership that are certainly worth member $$ - but it remains that RAA needs to discharge its responsibilities as an 'accredited' agent of CASA in the most cost-effective and efficient manner possible.

 

Continuing to operate with labour-intensive (and audit-indefensible) manual systems is simply not a viable option for RAA. What I would seek is an indication that RAA has both realised AND planned for a move to a viable system of business processing that is consistent with modern practice.

 

 

Bruce, you display a lack of knowledge of the combustible nature of sea-water. This is in fact a known problem: see: http://www.thegoonshow.net/scripts_show.asp?title=s07e21_insurance_the_white_mans_burden

 

SEAGOON:

 

You mean you're offering me free of charge the deeds to the English channel?

 

GRYTPYPE:

 

He heard you Moriarty.

 

MORIARTY:

 

Do you accept the English channel then, le channel englais?

 

SEAGOON:

 

Yes. I only hope I can live up to it.

 

GRYTPYPE:

 

I'm sure you can Neddie. However, one slight formality Neddie. For your own protection of course, the jokal style of protection, you must insure it lad.

 

SEAGOON:

 

Insure it against what?

 

GRYTPYPE:

 

Fire Neddie

 

MORIARTY:

 

Yes, fire Neddie. And fortunately for vous we happen to be strolling insurance agents of no fixed percentage.

 

I think we ought all to realise that changing to a Li-whatever battery might be an insurance risk...

 

 

Sorry, jj - can't help you here, our engine has a CAMit alternator and Ian's will also (obviously!). However, it occurs that you don't need a test cell for this; just a representative Jab. charging system set-up with an electric motor to spin it. I'll have a scrounge through my 'old parts' bin and see what's there and what can be done; since I am very keen to use a LiFePO4 battery, some testing would seem to be sensible.

 

 

You know what, Merv - I have to admit, you have a point. The filthy weather here (you will know it) has driven me indoors, but it's promising to lift and give me opportunity to get on with doing stuff that helps the 99% of Jab engine owners that don't agree with your and Deadstick's propaganda. So, I'm out of here, to do things that are useful.

 

 

Just a minor point, but given the aircraft is 24 reg how exactly is it that you are going to legally fit this????

Good point: it's up to Jabiru to make a determination that this as acceptable for a 24-reg aircraft. Perhaps someone should ask this of Jabiru; perhaps RAA could be a conduit here?

 

 

Geez, Merv, what a put-down. I feel terribly humbled.

 

Yet, I take heart in the fact that I was issued a Dept. of Transport 'Glider Inspectors Certificate', with endorsements for D.I's for Wood, Metal, FRP, Steel Tube and 'All Types'; 'Standard Repairs' for GRP, 'Replacement of Components' for everything; 'Approved Modifications' for FRP and 'Issue of C of A' for Metal and FRP' - in 1978, when DoT was CASA.

 

You can equate that to at least an L2 for RAA aircraft. DoT didn't hand that qualification out with packets of cornflakes, me old Mukka - because we were delegated authorities under the regulations.

 

So don't hand me the 'librarian' tag; I have the certification to prove my competence to the requirements of the Australian Government agency responsible for Aviation safety in force at the time.

 

 

An MGL 'Extreme' EFIS - with full EMIS capability, including recording, with four CHT and four egt probes, costs less that $2k. ( http://www.lightflying.com.au/Stratomaster Pages/StratoPrices.htm)

 

Yes, CAMit engines are an order of magnitude improved and the calibrated test results to prove it will shortly be forthcoming. However, the assertion that the 'base' of the Jabiru engine is as bad as you decry, is statistically disproved; it's the engines you maintain that are out on the extreme end of the reliability bell-curve. If I were an L2, I'd not be touting your record when there are numerous examples of FTF's getting highly acceptable life-times from Jab. engines due to good maintenance and good use management practices.

 

Post moderated...warning on content (Mod)

 

 

Bit of a let-down from your promise of news in 1-2 weeks made on July 25 that hasn't materialised, but jeez, that's how these things go, eh?

 

We'll be looking forward to some serious, 'take-it-to-the-bank' stuff.

 

 

The solid statistics (from your excellent research) show an approximately 4% forced landing result from Jab. engine problems, including a few which appeared to be precautionary and MAY have been incorrectly diagnosed icing. While that is not as good as fewer instances, it isn't indicative of a tsunami of occurrences, as some would try to suggest.

 

 

Ah, Queensland - beautiful one day, fur-packed the next...

 

 

Some (too short yet to make definite conclusions, though) test running of a J2200 in a test cell environment where a number of the normal installation problems (especially uneven cylinder head cooling) are eliminated is starting to suggest in fairly strong terms that a considerable amount of the Jab. uneven mixture problems may be due to the installation upstream of the carby i.e. the airbox and the scat tube air delivery hose. More investigation will be undertaken before conclusions will be drawn but so far it seems a promising line of enquiry.

 

 

As I participated in a calibration test of the temperature thermocouples on a (J2200) test engine two days ago, this is an interesting thread!. The chts tested are thread-in-head types so I can't comment whether the results apply to the under-plug types, but the entire test installation was tested using a pair of labaratory-quality mercury-in-glass thermometers with the temps averaged between them and tested both on the rise and the fall of temp. in a large brass block, to ensure that any position error between the thermometers and the actual probe positions on the block for both rise and fall of temp was averaged.

 

The end result is that there are minor changes in recording AT THE INSTRUMENT through the range 60C - 200C for each probe, and each probe had slight variances for where divergence occurred - but they were, on the whole, very accurate. This was on a 'test' engine set-up, with the (compensating cold junction) instruments located in a separate room from the engine itself so one can count on the cold junction environment being entirely stable. The tests were conducted on the actual probes and the complete wiring used on the test engine.

 

Suffice it to say that provided the actual cht reporting set-up is reliable from probe to instrument read-out, the accuracy of the temps. reported by decent-quality probes will be better than one can realistically assimilate in real-life flying as a guide to what the engine is doing at any particular moment. Having a recording capability that one can examine later, however, could be very illuminating as to how the engine behaves.

 

 

It's a long time ago but maybe about 3 1/2 ozs x 4, or about 8 mm thick.Yes, the oxygen was excluded from inside the tank, but the flames were working over the outside of the tank.

I recall reading something about the NASA re-entry skin design where someone discovered it didn't have to be fireproof, just achieve a slow detrition rate (there is a specific name for it), and that's what they did before they went to ceramic tiles.

I suggest that the petrol inside was actually acting as a coolant - given the thickness of the matrix - and may well have done so for a while until enough of it escaped (burned-off), had the fire brigade not been there - then BOOM!. A metal tank would likely have reached BOOM rather more quickly, so one up for the 'glass, I believe. Most vehicle fuel tanks nowadays are (as far as I am aware) some breed of cross-linked PE, so let's not disparage a 'glass, or plastic, fuel tank. I don't believe there have been any crash-and-burn accidents for Jabirus (essentially, always 'glass tanks in one form or another), whereas there have been quite a number of complete annihilation fire results with metal -tanked aircraft (e.g. the RV6 at Gatton recently),which I suggest results from stress rupture of the tank structure allowing fuel to leak at a fast rate and once ignited, it's going to burn until exhausted / smothered.

 

This image of the Cootes' tanker fire at Mona Vale shows how extreme a ruptured steel petrol tank spreads fire: http://resources0.news.com.au/images/2013/10/09/1226735/408924-3f57f8a6-307d-11e3-a489-bd783c3f5e8c.jpg

 

I built several alloy fuel tanks for small racing cars (before these had to be built by a certified builder), with the requisite foam fill, and they are a bugger to build effectively to avoid cracking at the seams and the restraint points (there are design tricks, and they are definitely in the category of 'don't try this at home'). I'd personally far prefer a 'glass tank built from aromatic-resistant 'glass than any other medium (it is hard to get, but available).

 

 

What you are seeing there is a hybrid: a 'space-frame' occupant cage that connects the mainspar, u/c and engine mounts thus keeping all the highly-stressed components flying along in harmony, and an essentially monocoque rear fuselage cone that provides light-weight stiffness to the empennage. A 'glass outer skin provides aerodynamics and by being easily removable (since it is not providing structural integrity), allows remarkable access to the control runs etc.

 

In the flesh, this is a very deep-chested aircraft - a bit like a Staffordshire Terrier by comparison to the Whippets of the small aircraft world. The 'Stroker' seat requires some of this depth, but there is also depth from an integrated pannier that contains usable load items in an entirely safe 'container' (that has low impact on c/g variation). It is the only aircraft that I've ever seen that one can easily remove a (large) outer panel and access the control runs for inspection, adjustment and maintenance.

 

 

Caveat: I am NOT an engineer and what follows is a series of observations, and I invite correction and comment that is based on the principle of trying to assist understanding of this whole issue of occupant safety. Dogmatic denial of what I offer based on nothing more than personal bias against specific aircraft does not help this matter; however qualification / questioning / additional information most certainly would.

 

I believe that a great deal of secondary safety comes (mainly) from two aspects: the dissipation of energy at a rate survivable by the occupants and a lack of intrusion to vital organs from structural members / unsurvivable collision of the human frame with the airframe.

 

Most small aircraft have a very limited amount of material around the occupants available to dissipate the energy in a crash - and that depends very much on the nature of the impact. As far as I am aware, for a near-vertical descent, (without impact absorbing seats), the only source for dissipation of energy is the u/c, which needs to be capable of collapse at a vertical speed at a rate that imparts non-lethal stresses on the lumbar and neck. Once the u/c has gone, any residual energy is pretty much guaranteed to kill / render the occupants at best, paraplegics. Some temper-foam on the seat is an addition to safety and though the compressibility characteristics are good, the secondary possibilities of belts loosening, 'submarining', coming into contact with bits of structure are all things that need to be considered - just adding some temper-foam may give you very little but confidence.

 

However, in an impact with decent forwards velocity, there's a lot more opportunity for 'good' characteristics in design and materials to come into play. Rather than get into an argument with anybody who feels that comparisons between specific aircraft are intended to disparage one vs the other, can we just look at the 'good' aspects of one type and people can muse on that and think about how other types match up.

 

I'm going to use Jabirus as my example of the combination of 'good' characteristics ( no surprise to those on this site that have read my previous posts).

 

I think that it is fair to say that the statistics show that Jabirus have an extremely good ratio of 'survivable' crashes (and a statistically meaningful incidence of crashes, let's be up-front there!). The idea that most of those crashes have been 'small' ones does not invalidate the observable results from significantly more serious ones.

 

http://www.jabirucrash.com/images-crash-site/Dscn1888.jpg

 

http://transform.fairfaxregional.com.au/transform/v1/crop/frm/silverstone-feed-data/ba98490d-a4d7-4765-9ea5-53f129e87037.jpg/r222_268_1432_989_w1200_h678_fmax.jpg

 

http://cdn-www.airliners.net/aviation-photos/middle/5/2/6/0656625.jpg

 

http://i859.photobucket.com/albums/ab160/bc_j400/mgt.png

 

What characterstics do Jabiru's have that provides a demonstrably decent level of occupant safety?

 

I suggest there are two major factors, and as almost always, these actually combine into a 'system'.

 

The first, is an effective 'occupant cage'. By the nature of a strut-braced high-wing single-tractor-engine design, there are three major load-bearing locations: the mainspar, the lift-strut and main u/c attachment and the engine mount. The occupants sit inside the triangle formed by those three connected points of strength. So, what is needed for occupant safety AND what is needed to keep the aircraft structurally sound as a conjunction of the three critical areas of load, work together. That has the advantage of crash worthiness being integral to the design structural requirements; or, in very simplistic terms - occupant safety and structural necessity coincide.

 

By comparison, a low-wing aircraft - and particularly one with a large 'cut-out' in the fuselage structure necessary to fit two occupants into a small package - in crude terms resembles a plank connecting the mainspar, the u/c and the engine, on top of which sit the occupants. All the occupant safety structure is essentially 'additional' to the basic structure that connects the main load-carrying structure - and that means, (again in crude terms), additional weight for the required characteristics. I'm not suggesting that a low-wing aircraft can not offer both good basic structural strength AND good occupant safety - but - due to the bloody stupid weight limitation restrictions for our class of aircraft - we pay an occupant safety penalty for 'redundant' weight in terms of 'usable' weight - and that translates to reduced range, carrying capacity and performance.

 

The second 'advantage' that Jabiru have over some other aircraft in terms of occupant safety comes from the selection of a low-tech composite structure. Jabirus are made from an ambient-cure, hand-laid glass-epoxy matrix. Not even vacuum-bagged to achieve a high glass-resin ratio. What does this mean?

 

Well, it means that in order to achieve the required stiffness, it is fundamentally excessively strong in terms of deflection to failure stresses. What is this? OK, let's try to develop some understandable examples.

 

Let's take a series of beams, of various materials, of 25mm wide and 300mm long. We'll put them in a vyce set vertically and put a weight hung from the outer end. Let's say, that weight is 5 kgs and the required deflection of the beam (for other structural reasons) has to be no more than 5mm. A beam of carbon fibre will almost certainly be the lightest construction that meets those specifications (leaving out 'unobtainium' materials such as Titanium, highly-exotic fibre reinforcements such as boron-fibre and (probably) materials involving nano-technology). High-end aluminum alloys will be next, I think, and good wood (sitka spruce, hoop pine) will be fairly well up there. 4130 steel will come into the picture.

 

If you are looking to materials that optimise the stiffness-to-weight ratio, the Jabiru composite will come in quite badly. However, if you then load that beam to the point where it fails to remain a beam and buckles, there is a different story. The Jabiru composite beam will deflect by a very large amount (and a very considerable weight) before it finally tears apart. The rise of resistance to force is reasonably linear, which gives the human frame a better chance to accommodate the circumstances up to the point of failure, akin to the old experiment of dropping an egg from 20 feet onto concrete or a thick down pillow. A structure that is 'excessively strong (rigid)' and does not deform until beyond the point of the body's tolerance simply transfers unsurvivable forces; a structure that is excessively 'weak' and deforms catastrophically while the occupants are still surviving is pretty obviously inadequate protection.

 

The next thing to consider is the behaviour of the structure surrounding the occupants when it does - eventually - fail. Jabs are basically a monocoque and a pair of cones with the join being at the occupants' shoulder region. If you take two cones and join them at their bases and then push from the pointy ends inwards, they will tend to fail at the join by it deflecting outwards - or AWAY from the occupants. There is no structure around a Jabiru cockpit that inherently will collapse inwards, crushing the occupants (provided, obviously, there isn't something trying to force its way in, such as a tree), and the curved shape of the 'cones' of structure will tend to ensure they fail outwards, away from the occupants. That curved shape is not only aerodynamically useful but also structurally useful, as the compund curves tend to diminish drumming of the structure - so that's a bit of a win-win as a result of the material choice. Mostly the same applies to a well-designed steel tube structure provided the tube(s) don't detach; however it needs to be recognised that steel tubes act mostly in direct compression /tension and so if there is a bending load applied on a tube acting in compression it will eventually collapse in the direction of the bend. And - generally speaking - once one member of a steel tube structure fails, others will follow until there is insufficient energy left, as they become over-stressed.

 

The final point that should be made is that, particularly in a low-tech composite structure, load paths have by necessity to be taken out over a fairly large area - you can't just put in small areas of high-stress to accommodate attachment of things because the nature of the material won't allow you to. That has the beneficial effect of transferring failure-level loads over a larger area and that larger area provides more material to progressively dissipate energy as it fails. The 'classic' Jabiru overturn accident shows repeatedly that the firewall (and therefore everything forwards of it) will eventually detach, torn away from the 'A' pillars, with (usually) relatively little damage to the actual occupant cell structure, absorbing quite a bit of the energy as it does.

 

Jabirus tend to 'bounce' rather well in the case of an accident, with the combination of the strength of the material and its ability to deflect quite considerably before failing serving to absorb at least some of the energy into deflecting the entire aircraft away from the 'hard' bits of the scenery. If you like, think of the difference between throwing an egg - for which the shell is a very stiff structure for its weight- against a wall vs throwing a squash ball at the same velocity, angle etc. Anybody who has owned a conventional fibreglass yacht will know how well they 'bounce' when you misjudge the approach to a wharf - for instance..

 

Jabirus are not 'perfect' - quite obviously. I would not be so silly as to suggest that they are; however they have a reputation for occupant safety that is enviable and statistically significant in this class of aircraft. If you simply examine closely a Jabiru while thinking about what may happen in a crash and compare that with the same situation for different aircraft with an appreciation of the 'system' that each aircraft offers in terms of occupant safety, I believe that you may have a better chance of, at least, being able to evaluate how well the aircraft you are considering (or flying now!) MAY protect you in a crash vs. what a Jabiru can deliver.

 

I'm not trying to set Jabirus up as 'the gold standard' here; however, statistically they are about as good as it gets in this class of aircraft. We all know that there is a price in terms of performance, usable weight etc. that Jabirus pay for their low-tech composite structure; nothing comes for free.

 

Absolutely everything we fly, drive, use in our daily lives is a compromise; what one chooses SHOULD be the set of compromises that you evaluate best suits your needs and situation. To make that choice, you need as much information as you can get (and understand). Jabirus offer a set of compromises that -and this is borne out by the statistics - tend to offer pretty good occupant safety in the operational environment in this class of aircraft. At the very least, understanding why that is may be of value.

 

 

It's the one on the outside of a double-skinned panel, Turbs.

 

 

Craig, you may also be interested to follow-up on the CAMit developments to the Jabiru engine, depending on whether you are going to register a 230D as an LSA or an experimental: http://camitaeroengines.net/pages/new-camit-aero-engines.

 

You will find a lot of information in this thread: http://www.recreationalflying.com/threads/camit-engines-anyone-got-one.114782/; since that thread ceased activity, there have been even more developments and CAMit are currently about to start a major programme of testing (intended to lead to certification) of their modified engines, though that will take some months to complete. The engine test cell required to conform to the test regime is under final commissioning work at the moment and should be ready to commence certification-level testing work in a few weeks; it has already undertaken a number of initial engine runs to ensure it can deliver the conditions and calibrated accuracy requirements necessary.

 

The status of CAMit certificated engines as a 'manufacturer's option' for an LSA aircraft rather than standard Jabiru engines is yet to be determined in Australia; however if I understand the situation correctly, Jabiru USA has an independent status as a 'manufacturer' in the USA for FAA purposes and it may be that it can accept the CAMit engine if it chooses to so do; you might find it useful to contact Jabiru USA and find out what their position is likely to be regarding the CAMit engine in the future as it may be an attractive alternative with the extensive modifications that it incorporates.

 

 

Thanks for posting that article Oscar. Proud owner of an rv7 which is an absolute delight to fly. It is so direct. Rv7 has slightly lower wing loading then the 6 I believe, but the reminder of how high wing loaded ac soak energy in banked turns with engine out was a good reminder. I have practised lots of engine outs with idle power, prop in fine'surprised that range is reduced so much with engine out. Might do some practicing aiming to arrive couple hundred feet high over threshold.

You are most welcome, if it has been of use to even one person then it was worth posting, I believe.

I have no idea of what changes there are between the RV7 and the RV6, but the 7 certainly seems to be a fine and safe aircraft. I don't follow VANs aircraft other than as a casual reader, but I certainly don't recall any questioning of their safety or flight behaviour at all.

 

 

For those who wish to increase their knowledge of flying a Vans RV6 in difficult situations and thus increase their safety, may I sincerely recommend: http://www.sdsefi.com/air44.htm This is a first-hand report on a deadstick landing (crash) coming from a person who is intensively involved with modifying (and air-racing) Vans RV6s.

 

For those who wish to pick an argument, then take it up with the author of that article.

 

 

Ah, my mistake, I thought the fuselage sill reinforcements came under an EO, but the intricacies of the Ex category elude me. I agree - it could not have been a cause of the accident - but MAY have been a factor in the result.

 

 

The existence of an EO for strengthening the cockpit is not 'unfounded speculation', nor is the lack of elevator authority in the case of an engine-out. The 'folding' situation has been proven. If you do not wish to acknowledge relevant information, fine by me, but don't deny that information to people whose lives might be saved by knowing it.

 

 

interesting to note in one report i have read, is that both occupants, were not found inside the aircraft, looks like they survived the crash, exited the aircraft, then succumbed to injuries.. or quite possible the pilot and passenger suffered heart attacks as shock set in, or the crash was caused by the pilot suffering something that incapacitated him/her, and the passenger suffering a heart attack from shock after the event... all purely speculation based on something i read that might or might not be factual... im sure the facts will come out shortly...

The reports I have seen indicate quite positively that the pilot was inside the cockpit.

 

 

Yeah one of my questions is regarding the survivability given the pretty intact and upright state of the aircraft, and that being on approach it was presumably fairly low speed. I find that puzzling.

The RV6 has two known and documented problems that MAY be relevant.

 

The first, is a known structural problem with cockpit strength, that in a crash allows the sides of the cockpit to deflect and cause the whole aircraft to fold as if hinged around the mainspar and bring the top of the panel back and crush the occupant's foreheads. Typically, once the 'fold' has happened, the aircraft flops back into a fairly normal-looking attitude; this effect was found under forensic examination to be the answer to otherwise inexplicable death. An EO was developed (in Australia) to assist in strengthening the cockpit, but even if this had been applied to this aircraft it is probable that the apparent descent angle would not have been survivable. An RV6 is not a particularly crash-worthy aircraft, and the statistics support this contention. It is nowhere near as potentially lethal as say a Lancair 240/260 or a Cirrus, but equally it is far below mainstream GA aircraft or even any Jabiru for crash survivability.

 

The second, is a lack of elevator authority in an engine-out situation that will not even allow a normal flare if under about 55 kts - the aircraft will just fly into the ground, no matter where the stick is being held.. Recovery from a low-speed stall would be absolutely impossible in an engine-out situation on the height reported.

 

Please let's not get into 'issues' here: two apparently fine, decent, loved and respected people have died from an unfortunate situation. Unlikely to have been pilot error, but due to fundamental characteristics of a particular aircraft.

 

 

Horrible news, and I add my condolences to everybody else's. An RV6, I think.