Oscar

Frank: how do you support your contentions? Unless I have read the voting incorrectly, Trevor Bange received the second highest number of votes. Trevor has been a hugely active contributor to recreational aviation in its various forms for almost 50 years; has been an Instructor and RTOA for the GFA, is a CFI, Instructor, L2 and L3, provides and maintains the airfield for the largest Recreational flying club in Australia on his own property. His entire family has/does support recreational aviation to a degree that I ask you to provide a better example. Give us all a better example of someone dedicated to furthering Recreational aviation.

Obviously, competition has significant advantages for the consumer (though one would have to examine the Banking Sector to form a true picture of just how much advantage there IS to 'the consumer' when 'competition' is in fact nothing more than varnish used to blur the vision of a hegemony). In the case of RAA, you have an intensely technical regime requiring strict performance. Let's be realistic: things like the magazine, (which is frankly pitched at the level of intelligence of an in-flight brochure), and fly-ins ( which can be very, very well-managed by local Flying Clubs) do not need need a multi-$M organisation. However, adherence to the applicable regulations to flying an aircraft in Australia, DOES need a high-level of technical expertise. Neither RAA nor AUF nor SAA have had the opportunity to contribute to the development of the regulations since HORSCOT - and there are very, very few people indeed in this country who have a comprehensive understanding of those regulations. There were two; one died several years ago and the other has responded to being invited to far cough by the owner of a popular Aviation web-site by doing just that. So: let us fantasise for a moment, about an alternative, competitive service to RAA. The actual mechanical processing of such things as registration, is not difficult - but from where does one source the expertise to ensure that the regulatory requirements are being met? You'd need people with experience of the regs. as imposed by CASA and as implemented by RAA. Now, the only people NOT already in RAA who have - ostensibly - some claim to such expertise would be those who are 'on the outer' with RAA at the moment. Not to put too fine a point upon it: Sergeant Runciman's Rejects Ragtime Band - which has briefly (and laughably) put its head above the trenches from a hangar in Bundy, only to demonstrate several times that it retains its unparalleled ability to fail to get anything done because of its ineptitude. Would you place any faith in that mob, to keep you flying legally? The same crew that gave you the mega-colossal registration screw-up? The failure to organise continuation of the Insurance? Membership number falsification? A massive Financial Control FAIL? Give me a break - that would be equivalent to giving Alexander Haigh control of the re-run of the Western Front battle.. So far, I have seen no better alternative to RAA as it currently stands to serve my modest flying ambitions. I have an open mind to any realistic alternative, but it will have to be way more realistic and believable than the Bundy Hangar Clown's Co-Opertative.

That's good information, thanks. In my fairly few to date flights in a 160, I found relatively little difference in pitch with minor power changes when using full flap, but that's very possibly because I was using a glide-approach profile anyway - old habits die hard I've found - so 'power' was mainly used as 'energy management'.

seb: standard set-up AFTER the carby - no airbox. But we were testing the capability of the test rig to deliver the conditions required - not the engine performance - so we didn't bother with numbers that would be meaningless anyway if not in the actual installation.

Merv: I would have expected no less of you. As we have commented upon many times in various threads, my power flying experience is inadequate from which to make any pronouncements, so your comments on this is of far greater value: could one successfully land a J160 using power control of pitch, on an average regional airstrip? I don't know whether Bundy was 'controlled' in the early 1990's , but it had a 'base' station.

Seb: Personally, I'd say that ALL of your cht's are quite decent: you are within about 4% spread (unless my maths is as bad as it often is..) Remember: the 1-3 side cylinders are forward of the 2-4 cylinders, so the 'ramp' effect for the intakes is quite a bit different. Cooling air just does NOT behave as one wants; it's a capricious bastard. I hope that one day, CAMit will reveal what its research has shown to be the problems with Jab engine cooling. To get balanced, controlled air delivery to each individual head, this is what your need ( my engine in that image): The small unused central outlet is for the oil cooler air supply; the two blanked off outer outlets are there for testing six-cylinder engines. As you can see, each cylinder air supply has a butterfly to allow balancing of the airflow to that head. The whole assembly is fed by a 6KW or so electric motor driving a squirrel-fan assembly about 25% the size of a Volkswagen Beetle (original version)!

Yes, Merv - I should have typed 'Bundy Controller'. 'Tower' was shorthand. Yes, power WILL affect pitch, but the usefulness of that in the case of trying to land depends on a number of factors, including the thrustline/drag line disposition, the engine offset and the prop. wash effect on the tailfeathers. Since you are a highly conscientious Instructor, I assume you teach 'secondary effects' - but do you teach pitch control through power management?

[quote=" One habit on 5215 was due to the lines coming up from the rear being bundled; you'd set take off trim, but when you did the final controls free and correct check, the trim control would slide forward with the yoke. I only ever noticed it sliding for take off, never saw it slide back, but that's a possibility. Pitch trim on Jabirus is managed by a spring balance arrangement at the elevator horn which is altered in position by the trim lever - so YES, it will move - in both directions - with a full-control-deflection check, unless the trim lever friction is excessive. It is designed to do what trim is supposed to do: relieve the pressure on the stick for a specific attitude. If you are setting trim BEFORE you have done the 'full, free and correct' check, then you need to go back and change your habits. The Jabiru elevator trim system provides a secondary (mechanical) safety for the elevator control: an essential safety feature. You can fly with rudder disconnected by use of the secondary effect of ailerons; you can fly with ailerons disconnected by the use of rudder (both under the proviso that the aircraft is actually aerodynamically balanced.) But there is NO 'secondary effect' to counter elevator control failure. Pitch trim control of the elevators by mechanical connection provides a back-up system; that this works, I know, as a family member once landed a Jabiru without fuss (other than from the Bundy tower, who was having hysterics about 'are you declaring an emergency' 'No, I just want a straight-in approach, please') with the main elevator control cable detached. Had there been a similar arrangement on that Morgan that went into the sea at Moruya last year (??) that accident might not have happened.

Seb - those are very good p-delta figures; your cooling set-up is fine. Don't obsess on the damn egt figures: the egt reporting is indicative at best, and is most useful for alerting to 'out of normal' excursions in flight for anything that doesn't have mixture control. As a general guide to mixture, the plug colour is a better guide than the egt's.

Obviously not this one: No Cookies | The Advertiser I'd be very interested to have a reference to the one mentioned -preferably with a piccy. As a Jab owner, I am concerned to know if there are potential weaknesses in the airframe - particularly in the occupant safety cage.

I think you mean the Myrtleford one, and if you look at the piccy at: ‘Miracle’ escape for pilot in Myrtleford crash you'll see that the a-pillars let go at the firewall, were not cut out as in this one. I hope we'll be told at least the basic details, as knowledge of what can happen allows people (at least in some circumstances), to make better-informed choices as to what is the likely 'least-worst' option. This particular crash looks to me as if it was a terribly sad case of extreme bad luck.

Very, very sad event and my condolences to all affected. I've never seen any pics of Jab crashes that have had both A-pillars taken out like that, even for the infamous Wedderburn crash into tree tops; I am thinking wire-strike on the power line that runs along the road adjacent to the crash site.

Good to see you back in the workshop, HITC - and beautiful work as always. Tinkerers like me, and serious builders like you, get withdrawal after a while... sure, we can give it up anytime we like, but now and then you just NEED another shot (at it..) to keep going.. I sincerely hope that people are reading thoughtfully ALL of the stuff you write, because it is very important that people who modify / build their own aircraft, understand the depth of thought that goes into this stuff. Just about everything in an aircraft is, in some way, part of a 'system' - and the entirety of that system has to work together. PART of 'working together' has to be a consideration - as you have bought out - of the consequences of failure of one part of the system affecting other parts (your throttle consideration is a fine example.) Standards (such as the FARs, BCARs etc.) are a basic guide in some, but not all, cases. Just how far the 'system' extends in making the difference between something with 'fall-back' safety features and something that doesn't, is not always obvious. Earlier in this thread, you explained your rudder-pedal-adjustment locking set-up and we discussed the 'fun' component of having that mechanism fail! Whereupon, it becomes crucial that the effective operation of secondary effects of controls become of acute interest to the pilot - (as I can attest). Here's another example, about which I think I can nowadays talk.. In the early days of the development of the Sunbird Seeker, the control linkages were a cross-frame torque tube to link the two sticks together for elevator control, with a secondary tube welded to that in the centre which held the aileron horn - pretty standard stuff. Don Adams had assembled an engineering consultancy team including Dafydd Llewellyn (for aerodynamics) and Bill Whitney (for structures), and test flying duties were shared between several people - Dafydd Llewellyn being one, and I think at that time, David Ayres another. David Ayres had been undertaking a series of tests, when the tube for the aileron control horn snapped off the main cross-tube - no ailerons ( the weld for the aileron control horn tube tore out). David was able to land the thing successfully, for two reasons: FIRSTLY, because even in the event of that significant failure, leaving the push-rods from each stick and the main aileron horn flapping around, they did not foul the operation of the elevators, and SECONDLY, because a (fairly recent) adjustment to the dihedral had ensured that the thing could be controlled in roll to a reasonable degree from secondary effects of rudder. Test pilots get to earn their money - but they only get to spend it if the 'system' they are reliant upon, works..

The concept that RAA can operate 'outside' of a CASA imprimatur is a foolish notion. Control of pretty much everything lager than a kite or a kiddie's balloon has by legislative instrument been handed to Federal authority, and CASA is just the latest incarnation of that (see also: DCA, DoT). This is not just an Australian 'invention': ICAO has been vested by international agreement with overarching control of pretty much anything that operates above 500 feet AGL. For example: WIGs that can't go above 500 feet AGL are boats, but are aircraft at 500 feet-plus. When all the BS about a 'Member's Organisation' is discarded, we fly (if RAA-registered) as a result of 'the King's Pleasure' bestowed by CASA upon an organisation allowed to manage the affairs of recreational aviators. It is RAA's role to ADMINISTER all of the various technical requirements that come from CASA, as the body with the actual legislative power (and responsibility). RAA exists on scraps off CASA's table, it does NOT have the luxury of demanding the size, shape or taste of those scraps. RAA has for too long been an entirely schizophrenic organisation: trying to be an overarching 'flying club' and the administrator of the agreed ( but not actually, in legal terms, 'delegated')authority for CASA. GFA IS a 'delegated' authority - which is why all gliders are VH-registered. Those who incessantly denigrate the RAA Board and the RAA administration, should present properly-researched and supported by FACT arguments as to where RAA has moved outside meeting CASA's requirements for its operation. Until that is done, there appear to me to be a few disgruntled individuals only too ready to shoot the messenger.

The passenger appears to be a Jack Russell terrier! (though it's a bit hard to tell). The Evektor has one of the worst fatality rates/100k hours of anything, in the USA, and a most concerningly high overall accident rate: http://jabiru.net.au/images/The%20Aviation%20Consumer%20-%20LSA%20Accidents.pdf.

The whole issue of ram air pressure in the airbox, MAY be very much affected by the input of the Balance Tube on Bing carbies. In the initial Gazelle test aircraft, when switching from cold to hot air intake, there was a massive effect on engine performance (for the rotax engines), they dropped power vastly when switched to hot air with no ram effect, to a dangerous level. Your chances of climbing out from a go-around with hot air 'ON' was nothing.

I blame that on my screen!. But I DID look at your piccy enlarged and thought: I think that's a K75.. which as I recall, got away from the harmonics of the K100 at around 100 kph that made them speed-ticket-bait. Had a CX500 Sports, bought as a rebuild project, but never got to it - I liked them very much, but other things intervened. And yes, the airbox was LARGE. I'm about to develop an airbox for my Jab. project and it won't be anything like what was originally on it.

Seb - I'll be very interested to hear your opinion of the digital manometer when you have some experience of it - I'm thinking of buying one of that model myself. I notice it has a 'record' function', that should be capable of correlating to recording from any EFIS (we will be using an MGL 'Extreme EFIS) to revs, ch's, egts and airspeed. I'm thinking of making up a double-gang shuttle valve so one could have inputs of both air intake and exhaust pressures on the heads on both sides ( the p-delta) that one could switch between in flight.

That rubber flap (if it was a standard Jab airbox) is there for backfire pressure relief, of course.. but certainly sufficient to relieve any ram-air pressure. Is that your K100? if so, what fuel pressure do the injectors require? I just happen to have a K100 engine complete in my workshop, which I bought for a WIG project that didn't happen, but I have in mind to use it to make a (road-going) leaning trike... once my Jab is completed and the workshop is looking bare of ridiculous projects..

I organised to tow a b-25 (with the wings outboard of the engines removed, obviously, to leave the landing gear!) up the road (Majura Road) from Canberra airport to our storage facility at Mitchell ACT, still have the 'wide load' permit. It only just fitted onto the road and we had to turn the props a bit at times (by hand, leaning out the windows) to clear road signs. When we got to the Federal Highway Junction, the cops on escort duty stopped all the traffic; a bloke jumped out of his car and shouted up to me: 'where are you taking that thing?' I shouted back: 'Down to Mitchell, but we are a bit lost, I think'. You could see the 'Smartar$e' comment forming on his face..

OK - the manometer tubes in the test cell only measure the air delivery pressure to the heads from the 'squid', for the purpose of tuning the individual head air delivery - not the p-delta, because the test cell doesn't replicate 'installation'. (not meant to, for the specified engine tests: as a result of the tests, the engine manufacturer sets the various limits for operation and it's up to the aircraft manufacturer (or builder) to derive an installation and operational limits for that installation that keep the engine within those limits). One of the interesting things we found when test running my engine, was that with the sump exposed to the full prop blast, there was overcooling of the engine oil. Since we had oil temp gauges both in the normal (bottom of sump) position AND in the line to the oil cooler (for control purposes, as some tests require running the oil very hot indeed for periods to see what the sensible temp. limit is), we could verify that happening - we had to wrap the sump in foam insulation to get the O/T to sensible! In a normal Jab installation, Rod designed the oil cooler to exit its air over the sump, but would have found that without the prop blast, the sump is not very effective at all; what happens is that there is enough cooling from the sump to have a boundary layer of cool oil but beyond that, the oil is hot and thin and that's what gets recirculated. The standard Jab. O/T probe at the bottom of the sump really is NOT measuring the temp. of the oil circulating through the engine, but the temp. of the oil sitting in the bottom of the sump... (another good reason to use a CAMit TOCA).

Seb, re the tube for the manometer: you might find that the clear vacuum tube used in milking machines could work. It looks like the standard Bunnings Aerospace clear tube but it has decent anti-collapse properties - not that you need that per se, but it MIGHT be useful if you're running from under the cowl down out the exit duct and back up into the cockpit via a footwell intake (which is how they did it on the early Jab. testing!) There is a place in Toowoomba that sells it, is a farmer's supply-type shop.

Seb - remember, this is fairly old technology in the metals etc. in use!. I grew up when running in a car ( or bike) was at least 1000 MILES of light - medium - medium-heavy - never 'flogging it' duty, varying revs, an oil change etc. ... She should be settling down, I think, by about 25 hours very nicely.

seb: I've spent too many years working on: a) British or French cars; and b: yachts, to be anything but anal-retentive about easy maintenance. I KNOW that Murphy is waiting for when I have to replace the widget-gasket that involves undoing a bespoke-thread widget-retainer, it will fall down into: a: the drainage hole designed to allow water ingress into the chassis rail, or b: the bottom of the bilge which is two metres below the floor at that point and 50mm wide, to be complacent. It's either avoid that, or be forced to kill somebody. It's been emotional at times.. Your seriously different chts side-to-side has me stuffed, also. The chances of two cht probes being out of whack is not believable. I'd be fascinated to see what you find with the digital manometer: is it something like this one, that automatically registers p-delta if you have a pair of inlets at the high and low pressure sides?: AU Air Pressure Meter ±13.79kPa Digital Manometer Gauge & Differential Pressure

The Extreme series has an RDAC which needs to be mounted inside the cowl so it measures ambient and auto-corrects the cht's.