Oscar

Fat fingers: MGL EMIS...

Updraught is damn attractive. My only worry about it for a Jab engine, is the potential heat to the ancillaries - in my case, the starter and the CAMit alternator, and hot-air exit onto the battery and the only possible location for the ngl EMIS module. I had not considered updarught as an option when I built the new cowlings, but when you think about it, the lower 'nostrils' are very suitable intakes for updraught cooling are in the ideal position in the high-climb attitude. For that reason, I am not modifying my moulds with the large 'lower' nostrils, I've made inserts into the lower cowl to fit the separated barrel plenum feed(s). Everything I have developed has to be considered a 'work in progress'; when we can do flight testing, I hope to be able to report the results.

Yep, that's a very good source of useful information. I made up a trial set of under-cylinder barrel baffles as per the Diagrams #3 and #4 in 'glass, to try on the engine test stand and see how the airflow was, but we didn't have a chance to run those tests. The closeness of the Jab pushrods makes getting the 'ideal' exit volume across the barrel length ( which is a function derived from the fin diameters, so I had to best guess the exit volumes around the pushrods) to maintain fairly even airflow right down the length of the barrel, to avoid barrel warping through differential heat, but here's what I came up with (on my dummy engine again).: I'm not much of a metal-basher, and to do those in alloy would require a set of solid moulds and more skills than I know I have, but maybe one day I'll find someone with the skills ( might take them across to Barry Manktelow and watch him break into knee-slapping laughter one day!) bit it'd be easier with CAMit barrels which don't have those annoying cut-out towards the base of the barrel. I know that Ian Bent was finding the temps at the top (head-end) fins was way more than he liked, and I think he was researching better barrel-cooling, but I haven't followed up that with him.

Well, the lower 'nostrils' have been reduced to two 2.25" round inlets to feed the barrel plenum - not 'howl cowl' intake style but I suppose some will think it's a bit that way! Yes, the expanding and contracting shape of the oil cooler ducts are for pressure recovery; I got the dimensions from Dafydd, but basically, I THINK it's an included angle from the cooler forwards and backwards of no more than about 12.5 degrees i.e. 6.25 degrees on every face. I had two objectives for that arrangement: firstly to get the cooler exhaust out of the low-pressure area of the cowl (obviously), but secondarily to mount the cooler not OFF the engine /mounts so the oil isn't being shaken and possibly frothed. So that duct is a self-supporting structure for the cooler (there are a pair of tubes bolted across the bottom of the cooler so its weight doesn't bend the cooler flanges: The 'nose' at the intake was moulded to fit the intake lip and seals with some bicycle inner-tube - which being already curved, fits beautifully!. The front simply plugs over the inlet. At the rear, two nut-plates allow the cooler to be detached and dropped off the bottom cowl so it can hang off its delivery tubes when the bottom cowl is removed for maintenance - a three-minute job to detach/replace. I have installed a CAMIT TOCA to keep the oil temp where it should be without excessive warm-up time. The whole thing is a tight fit under the engine but with enough room ( I HOPE!) to allow engine rocking without touching:

To get a handle on just how rotten CASA is internally, see: 'Palace Revolution', in: ProAviation’s submission to the ASRR | Pro Aviation Thank you, Dick Smith, this is what you gave to us.

Thanks for the nice words, Seb - and yours looks very schmick, I have to say. I had to build new cowls - mine were originally for the 1600 engine (that aircraft was used as one of the factory hacks to develop the 2200) and were altogether a nightmare - cut-and shut inlets roughly done, and the lower cowl practically touching the muffler with large, badly scorched areas in it. The join flange between the bottom and top halves of the cowls at the #1 head had been cut out to clear the fins but was still rubbing on them at the front.. (That's a cardboard mailing tube doing duty as a fake muffler on my dummy engine, as mine was still up at near Toowoomba being used to develop the engine test running cell when I started building the new ones). Similar scorching on the rhs as well.. An interesting point I picked up from that guy I mentioned at Camden who has done such a great job: too much exit lip at too steep an angle can cause the flow to stall off its back edge in steeper climbs and that will badly effect the outlet efficiency; when I last talked to him he was judiciously pruning it back a bit, with his usual methodical approach.

NACA ducts are over-rated as a means of 'scooping' airflow - they work very well for transferring high-pressure to lower pressure areas with minimum airflow drag, but they don't 'grab' passing air and force it into a new direction. If you don't have a decent p-delta between the intake and the exhaust side of a NACA duct, they look good but don't do the job as well as a scoop-type intake. Getting decent air-feed to all cylinder heads in standard Jab ram-ducts is extremely fiddly; I spent, late last year, some time with a guy down at Camden who has managed it on his J160, and the amount of research (and the quality of it) that he had done to achieve really impressive results, was outstanding. He even put a borescope camera into the ram ducts and wool-tufted the baffles to fine tune them - and found that a few mm. of difference between the baffle shape between left and right sides was quite critical. He spent literally MONTHS of work fettling, testing to a tightly-controlled regime, changing one parameter slightly, re-testing.. Since I needed to build new cowls for my own beastie, in consultation with Dafydd Llewellyn who has a great deal of experience in this area, I've gone a completely different route - and I can't yet say that it will work!. But, I've used the work that was done on the prototype Jab engine install for a Bristell, that had good results.. so I'm hoping.. First up, I wanted to get the oil cooler air circuit clear of the cowl so it didn't reduce the cowl low pressure side p-delta. A completely separate duct system was needed for that: and this is what I came up with, to accommodate a seven-row Aero-classics cooler: That makes better sense in the context of the lower cowl: (Those 'quarter-donut' shaped lower inlets have been modified since that piccy was taken to a pair of circular intakes inserted in the holes; the oil cooler inlet remains the same. I have added a larger-base diameter spinner, roughly the same as on the newer Jabs, though from my own mould.). Because this work has a significant duty to perform as research into the requirement for head AND barrel cooling, I've completely separated the cooling for both - though eventually, it may prove to be unnecessary. The upper-cowl intakes supply ONLY the head cooling, while the lower ones supply the barrel cooling. For the head cooling, I want to get the intakes to operate with best efficiency for prop blast effect - which means getting the maximum intake area out into the area where the prop actually has effective blade shape: The bump on the top of the cowl had to be added to clear the starter motor, and the oil check plate allows for a CAMIT barrel -inhibitor system, not shown on the next piccy) So - what does all of that feed? All the baffles there, are templates for fitting cut from old scrap aluminium sheet that's been hanging around my workshop for nearly 30 years- not the real ones. And there's more, but I don't have useful piccies of them. The barrel cooling is fed by a pair of 2.25"tubes from those lower intakes,and will exit through under-barrel baffles designed to meet - as best I can manage - the NASA research for cooling design for in-line air-cooled engines. I'll probably have the final baffles, complete with MacFarlane 'Cowl-saver' baffle seal attached, in a few weeks - if Winter would sod off. It's taken more than six months of part-time work to develop the cowl moulds, the baffles etc. - only a complete nutter like me would DO that. AND - I don't know if it will work! But, it keeps me from making a fool of myself by going 'clubbing', or being reduced to golf for a hobby. I DO recognise that I may need professional help here, to get me over my compulsive tinkering obsession...

Ok, Turbs, I did not expect you to provide anything cogent. Since (if RAA has 10K members), I expect that about 9,995 are not concerned with this 'issue', it actually doesn't matter.

Since I am not a member of RAA and therefore haven't received any papers etc., can you please tell me when Nominations CLOSED for the election?

Not good enough. You are hiding behind weasel words, Turbs, bring forward your explicit explanation of the situation. Less than this is simply trolling.

There is a real issue with the 'new' real post times due to Aus.Post being radically reamed, drilled and stuffed up. Many government instrumentalities are operating on the basis that their posted notices have to be responded to within a fixed period (e.g. Centrelink, 14 days notice typically), and the actual notices are not being received by the 'respond by' ultimatum in more remote areas.. RAA does NOT run a private postal service: it has to rely on what is available.

Very, very good points - all of them. It should never be taken that any one design will necessarily offer better (or worse) protection in any specific situation until the actual dynamics of that situation are examined. However, it would be a whole lots more useful if there were readily-available information of the relative merits / dangers, such as they may be, of various options, that does not require one to be a de-facto structural engineer and a physicist to understand. It would ALSO be damn helpful if there was a fair bit more 'truth' in both advertising and flight reports, reviews etc. to allow people to get a better picture of what they were looking to purchase. Here's an example of what I mean: Ostensibly, a lexan canopy is a significant advantage over an acrylic one: I know which I'd rather be behind in case of bird strike - lexan, quite simply. I wish that a lexan windscreen was available for my Jab. I would have, with that, acrylic side windows, however. Why? In an overturn event - which is quite a common occurrence for Jabs, just as for any small aircraft ( and let's be fair, Jabs end up dead ants quite frequently!) - you very likely can't get your feet out from under the panel. A nimble youngster might be able to twist and turn but basically the centre 'spine' on which the brake, trim, fuel etc. levers are housed makes it bloody near impossible for us somewhat more mobility-challenged as a result of anno domini. If you can't bring your feet to bear on the exit route, thus being able to: a) apply considerable force with your back braced against the seat, and b) being able to spread that load widely enough to really kick out a body-sized hole, your only option is your hands and arms to which they are attached. Now let's look at that situation. You are upside-down, and it's pretty damn unlikely that you can reach the windscreen /canopy moulding in front - where you could perhaps brace your shoulders on the seat-back so as to exert some reasonable force, especially when still in the harness. If you undo the harness to give you better proximity to the windscreen/canopy, you are going to have to brace yourself using one arm at least, thus reducing your potential of applying force. About the only realistic option for that, resolves to punching vigorously with one hand. Now, ANY windscreen /canopy that has even mild pretensions of bird-strike safety - let alone just withstanding the air pressure of flight up to VNE - is NOT going to be in the slightest fazed by someone battering it with their fist UNLESS it is already severely cracked anyway. I'd not give myself a rat's chance in a mincing machine of being able to punch out anything from an unbroken Jab. acrylic windscreen , and Lexan is one of the most popular materials for the construction of 'bullet-proof' viewing panes... Acrylic will shatter with fairly minimal bending, leaving you with 'fault lines' that you can potentially use to break out growingly larger areas. You'd need to be careful to not get your hand trapped, however. What do I mean - trapped? IF you manage to punch through a small broken area, but that then grabs your wrist - closing up on your wrist after your fist has penetrated the area - you are suddenly in more trouble than Ned Kelly. And here is where a broken bubble canopy is really your worst enemy. A highly-curved surface such as a bubble canopy, when penetrated from the inside, is an extremely effective 'trap' - as you try to pull your trapped hand back, it closes over it. Somewhat like a lobster-pot neck.. A relatively flat screen MAY allow you to retract your hand - painfully - through distorting the material inwards, but a bubble canopy is almost an ideal shape to just continue to tighten up around your wrist. Getting back to my comment about having the side windows in my Jab. made of acrylic... even if, in an overturn, the doors (both, remember) cannot be opened enough for exit because the wings have been folded down around them (which I don''t think has ever happened in a Jab, but is certainly possible), I still have a moderate chance of being able to punch out the side window on my door by swinging my arm with all the force that an adrenaline-fuelled desire to continue to live would provide. I am NOT using Jabs. as a promotion exercise here: I am using them as an example because I have all the evidence of the results of an overturn, in my own aircraft. The windscreen was broken - a bit: The doors were completely undamaged and operable. There were some blood spots on the cockpit headliner - it looks like a result of the headset hanger tearing the nut-plate of the pilot/passenger. I know that the injuries were extremely minimal, but I'll bet someone had a nasty headache. As you can see, the nosewheel fork was quite bent. The wings have both been scrapped and the complete fin and rudder replaced. More damage was done to the fuselage by ham-fisted recovery than by the actual overturn.

I've been reading all of the above with considerable curiosity. I see a variance of opinions - but NO suggestion as to what other body than RAA could provide the necessary functions to keep recreational-class aviators flying, as a bottom line. Don't even try on me suggesting that Myles and his Bundy mob could replace RAA - it has repeatedly demonstrated that it can't find its own buttocks using both hands plus a map and shouted instructions, and even if surreptitiously supported (unofficially) by some within CASA, simply would not have the expertise nor the infrastructure to meet all of the RAA functions. It is very, very damaged good already. Anybody who pins their hopes on a group of rejects from the Runciman/Tizzard era, possibly (unofficially) supported by one or more of the SASAO staff to be able to magically spring up with an effective alternate RAA if they can pull the RAA Board down, is 'dreaming' - and badly 'dreaming', at that. There will be no just pre-Christmas presents for RAA members there. The only alternative to the RAA is direct CASA control: and that means the RPL, no owner maintenance other than for 'experimental' aircraft, GA costs for VFR-restricted and airspace-restricted aircraft. No general support for the recreational aviation community. Be VERY careful, in what you wish for.

I had a bit to do with Ray Funnell ('Roger Ramjet', as he was nicknamed) when he was CAS and on the Council of the AWM. I actually first met him as ADC to GG Sir John Kerr, for which position I have to say he was massively underutilised in his abilities. I found him to be a very decent bloke, and - contrary to the old saw about fighter pilots - you COULD tell him 'much' - and he would not just listen but take in, compute, and come back with a thoroughly intelligent response. I heard the stories about him wearing flight overalls in the office as CAS and frankly, I suspect that when he did, it was quite probably because he found them more comfortable than full dress uniform. Alan Hawke (secretary to DVA and later of Defence) used to wear trackies and running sneakers in the office when he didn't have 'representative' duties that day; I personally admire people at the top level who actually arrive to do their job with more regard to being comfortable to get on with it than concerned with their image. It's a wee bit confronting to be giving a briefing to your ultimate Boss in your pinstripe and tie, when he's wearing trackies. OK, Ray as CAS did have his personal Macchi painted white with the golden eagle on the tail which he used to visit RAAF bases to do snap inspections (as if they wouldn't have been informed that RR was incoming..), and I know the (probably urban myth) story that he once took off from Learmonth and headed west in IFR conditions until his navigator suggested that perhaps they were headed in the wrong direction for home... but I found Ray to be a pretty good example of a damn good person coming from the upper echelons of Defence. And there are plenty of those, with some glaring exceptions - of whom I believe McCormick to be one. Another was Gration - and I won't go there.

When George Markey built his Ultrabat Mk 11 (though it never had that name officially) in the USA, it had a Rotax two-stroke that continually broke down on him. He commented to me one day that one of the reasons he was trying to develop a new engine for it was that he got 'sick of having to slide it down on the roads, weaving between the damn power lines'. (Those who knew George would know he didn't actually use the word 'damn', but something more closely suggesting sexual activity.) I think that was in the area around Mojave or possibly somewhere in southern Nevada, which has a lot of reasonably flat ground, but his preference was for roads.

Indeed it is; it appears that it did a forward 360 roll, basically turning the fuselage into a sausage with the 'occupant cage' remaining reasonably intact and by the report, not deforming so badly that it did really life-threatening injuries. Let's be realistic here. I doubt if anyone - even the best of us, and I certainly do NOT include myself even within sight of that - anticipates an overturn result from a landing, even in emergency conditions, in most cases. A ditching - yes, we'd be silly to NOT anticipate that eventuality, but overturns are usually the result of the aircraft hitting a ditch or something similar, which in most cases we can't damn well see in time to take it into consideration. Irrigation country with water supply channels is the probable exception: I've outlanded in a glider in such a field and you most certainly don't land across those. Cane fields with their clear maintenance tracks sare probably another clear message of where to point the thing, but the u/c hanging down is very likely to flip you anyway. On the upside, in a cane field you have the vertical equivalent of the 'brush' centre-strips on some highways to provide a cushion. In a high-wing aircraft you can crack the doors before landing with little aerodynamic effect; for a lot of low-wing aircraft, the canopy is a lifting surface and if you crack it for enhanced exit potential you may well seriously affect the efficiency of the elevator, reducing your chance of slowing the damn thing down to minimise the kinetic energy of the crash. For a forward-hinged canopy, cracking it may also adversely affect rudder effectiveness reducing your chances of dodging the worst of the obstacles you may have to dodge, or aligning it with the waves if ditching. Cracking a rear-hinged canopy will most likely cause it to depart very suddenly, and if it hits the fin and rudder you have probably lost one control option. Low-wing aircraft with doors rather than hinged canopies - e.g. Piper Pa-28s, Beech singles, Mooneys etc, have significant structural members both ahead of the door(s) and behind them. They have a 'roof' structure as well, so there is a reasonable occupant safety cage that is quite obviously not there for hinged-canopy aircraft. I suggest, that this thread has bought out issues of importance in the choice of aircraft for the sort of flying one does. If you routinely fly in situations where even a forced landing is very unlikely to result in overturn, a low-wing, hinged canopy aircraft is a fairly low-risk option. If you have a BRS and are happy to use it if the apparent need happens - no problem. If you just want to hack around everywhere, including occasional transits of difficult country, then for me a high-wing aircraft offers greater secondary safety if things go pear-shaped.

Mighty difference between an acrylic canopy and a lexan canopy. An acrylic will shatter and be - once basically broken - easy to punch out shearing the attachment fixtures. A lexan canopy will take quite large amounts of deformation without shattering, and be very difficult to punch out if you can't get enough force on the edge attachment fixings.

Often leading to an OSH1T moment...

Jeez, Bex - you sprung me!. You are NOT paranoid - I AM out to get you - obviously!. My comments re the basics of wing configuration potentially impacting on occupant safety could not POSSIBLY be general observations about the inherent structural differences between low-wing and high-wing aircraft, since yours is the only low-wing aircraft design. Ever. FWIW: such is the path bestrewn with rakes in the grass for those with the genius to think outside the box (and yes, that was a deliberate pun). The fact that a fairly recent examination of crash statistics undertaken in the USA ( and I frankly cannot be ar$ed to chase it down right now) shows that the safest aircraft from a fatality POV were Jabs,. C150s and C172s - all of them, obviously by coincidence high-wing aircraft - is just another spurious fact designed to delude those who seek to find a safe option. Bex - all those statistics, all the structural analysis etc. - it's all dodgy science probably being supported by the UN clique out to subject the aviation world to the rule of communists bent on subjecting us all to high-wing aircraft. And - to my shame - I've been seduced by all of that. Fight on, mighty warrior! Save the world from expensive, over-hyped aircraft. And may your colour schemes be with you!.

Several years ago, I looked at the RAA accident reports over a period of about a year and found that a very significant proportion of serious landing accidents ended in overturns. I can't vouch for the completeness of those reports, but from memory, my conclusions were that it was around a 50% chance of ending up 'dead ants'. By 'serious', I mean those that are in the 'accident' category for ATSB: major damage / injury. I would NOT put this up as an authoritative statistical summary, but as a general indication, I found it quite sobering. In our class of aircraft, with MTOW limits that really stretch the requirement to make every last kg as effective as possible just for decent performance, the possibility of having 'redundant' strength for improved crashworthiness, is very limited. The most likely basic design to provide decent crashworthiness ALSO utilises the basic structure to provide a 'safety cage' concept: two results for the price of one, in weight terms. A high-wing design must tie in the load forces coming from the engine, wings, liveware (occupants), fuel and other disposable weight and undercarriage. In a 'traditional' tractor-engine, high wing design, the c/g requirement means the occupants HAVE to be sitting in what is effectively a 'box' of reasonably (sufficiently) strong form to tie all of those load forces. In a low-wing design, what you have is basically a beam comprising the mainspar and main legs, with a truss forward of that to hold the engine and nosegear, for a tricycle u/c design. The occupants are sitting (mostly) OUTSIDE the 'strength' structure: especially the upper torso, upper spine and head. Decent protection for what are your most vulnerable parts, has to be added to the structure - adding weight. At a minimum, you need for protection the equivalent of a 'roll bar' - as Nev says - that does not contribute to the basic strength of the aircraft, it is a parasite in terms of the aircraft empty weight. Plus: for a low-wing design, it is in practical terms impossible to have a 'closed box' structure; the cabin deformation that is a feature of the RV6 in a crash is a classic example of how this happens. (Later models of the RV6 style design have much better occupant safety). Without beating the 'Jabiru' drum: Jab's very frequently end up inverted from landing accidents and they have an almost unmatched - I believe - occupant safety record. Part of that is a result of the form of construction, which is extremely damage-tolerant, but a lot also has to do with the fact that they provide a very, very good occupant safety cage. Low-wing GA aircraft can be good for occupant safety by using their greater MTOW limits to allow the additional strength for occupant safety. I have no idea of the statistics, but I would suspect that - for example -there is not a lot to choose between say Piper low-wing and Cessna high wing light GA aircraft. However, I can't readily think of any Piper/Beechcraft/Mooney etc. GA aircraft that have hinged canopies..

A very cogent question - but surely one that applies to ALL candidates?

OK, I was at Amaroo Park for the Castrol 6-hour in 1977. Mike Hailwood's return to racing, on a 750SS Duc. Sitting at the top of the Loop, between a bunch of Rebels and Hell's Angels, smoking non-commnercial tobacco substitute and drinking Blue Heavens. You could hear the 750 coming up the hill, and after a few laps, EVERYBODY on the Hill stood at the fence watching Hailwood slice through the pack through the Loop. In bloody silence, just listening to the Duc exhaust. Mike slipped his shoulders through the pack, with his knees clamped to the tank and using the toes of his boots as lean indicators - none of this 'off the tank and use the knees' nonsense. Absolute magic.

Um, the phrase: 'too much information' comes to mind. Somehow, it reminds me of my ex-wife, with the ' No, I don't want a milkshake, I'll just have a sip ( meaning 3/4's ) of yours.. But I remember vividly riding across Commonwealth Avenue Bridge (Canberra) at the head of around 5,000 motorcyclists on the 'anti-headlight-on Rally' we organised in 1980, with my then wife sitting backwards on the pillion seat taking photos. ( Canberra 1980 "No Lights On" Protest Run memories) We had split the run across the two bridges, I led one stream, a mate led the other. Of all the 'BUGGER' memories I have of that: the head of the ACT motorcycle police - with whom we made great friends in organising the Rally - had invited us to dinner on the night before the run, with a 'mate over from NZ'. We declined in order to stay on the campsite that evening. Turned out: his mate was Graeme Crosby - yes, 'CROZ', one of my all-time motorcycling heroes. They used to street race together in Pukekhoie as lads. FARK Bugger SH1T. But as a result of that event, motorcyclists got a dedicated place on the Motor Vehicle Performance and Safety Standards Advisory Committee.

Surely, common sense indicates that this should be a description of the period during which an engine failure requires an 'extreme' emergency response: a 'one-shot' decision to (hopefully) mitigate disastrous consequences. An engine failure before V1, means you stay on the ground.. An engine failure at any cruising altitude, means (in our class of aircraft), that you should be in a position to undertake a 'forced landing'. To me, an EFATO occurs in that regime where a safe 'turn-back' is not possible, and nor is there a selection process of viable forced landing sites available. In crude terms: it is the: 'oh sh!t, THERE, make it happen right' situation. For a recent example: landing on the Golf Course beside Bankstown. Or in the pond therein.

Ah, kids: love 'em or loathe 'em, you aren't allowed to hit 'em with a shovel.. they keep telling me.