Oscar

SSCBD, yes the tomahawk doesn't love being slow, and it will punish you if you let it get slow. Probably one of the things a lot of people hate about it, but I think the disciplined speed control required to fly the tomahawk well is a positive rather than a negative.

 

Then if your not comfortable that is a good call not to fly it on your own, but I really strongly suggest go and fly it with someone until you do get comfortable, it will definitely improve your flying and once you get used to the tommy it can be fun.

Enquiring minds would like to know.

Exactly.A manufacturer should do a very comprehensive series of tests to demonstrate compliance so it is not cheap.

 

http://www.flighttestsafety.org/images/stories/workshop/2010/07-Sky_Catcher_Flight_Test_Spin_Testing.ppt

 

Some don't get it right, like the Piper Tomahawk Darren Smith's CFI Homepage Flight Instruction Website Tampa

The Sky Catcher one, is most interesting: if you look at the progression of the design changes, you can see the quite large addition of vertical tail-surface area required to get the thing to an acceptable situation. And that is for testing at (if I remember correctly), 32% of MAC.

Those of an enquiring mind seeking to understand why Milan Bristela designs feature so badly in accident statistics, might like to overlay a profile view of the CAW Sports Cruiser, the Piper Sports and the Bristell, onto the Skycatcher profile. And they might like to wonder whether an aft c/g position of 38% of MAC for the Bristell is entirely a wise decision. An expert aerodynamacist will tell you that there are additional questionable factors, such as the absence of decent wing-root fillets in the Bristell.

That Cessna could get a new design so far wrong, is a mystery. However, the referenced .ppt demonstrates that they did the testing, found the problems, eventually fixed them.

Down here, in our own little corner of world aviation, Jabiru produced thousands of aircraft in the same class. None were lost in testing; none have inexplicable crashes from dubious aerodynamic performance.

That isn't just from luck.

RV-12 spin testing:

 

Yes Oscar, that's the sort of performance I'd like. A compromise between extreme smack-down and good cruiser- with the added bonus of an excellent safety cage.

The 170 tail volume and longer tail-boom leverage over the early LSA55's should provide most of the tail-feather power to keep things controllable at a lower stall speed. You might need to play around with vg's on the underside of the horizontal stabiliser, though. I think you would find the advice of the aerodynamasist Rod used to be much against enlarging either the rudder or elevator volumes ( as per the LSA55 in Post #5), as that could introduce flutter unless you very carefully add mass balance ( which isn't used on the rudder anyway, but might be able to be added to the aerodynamic balance tab on the rudder, but NOT without consulting Alan Kerr re the structural considerations! ( I made a small change to the rudder configuration - not enlarging, just to fair it in to the fin better, and the advice I was given, is that you have a margin of about 5% in safety for the c/g of a flight control surface relative to the hinge-line that has been tested to be flutter-free.

You'd need to get the wing vg's right. To ensure you have benign stall characteristics at slow speed, the centre-section of the wings has to stall before the ailerons do - and if that happens too soon, then you lose down-wash onto the elevator and that in turn could cause a highly exciting stall... right near the hard brown bit underneath.

When I look at the 'extreme STOL' aircraft', I see things that are very, very draggy - so you can fly them down with quite a bit of power-on and still land very short. Even an optimised J170 will be quite a bit more slippery than those... and the old Ke= 1/2MV2 is your enemy...

But, as the old saying goes, it's not how big it is but how you use it... I know an old Jab. test pilot ( you know him too), who could get an LSA55 down pretty damn short, using glider tuggie techniques and dumping the flaps at just the right moment. He told me this story..

Max Hazelton once visited Nestor Slepcev at Nestor's private home strip. Nestor was apparently somewhat taken aback that Max had arrived in his Auster - not believing that anything other than his (Nestor's) own creation could use that strip - and told Max that he'd not be able to get off again. I believe that Max politely told Nestor that he'd 'give it a try', and left with no more fuss than that with which he'd arrived...

At last someone agrees with me. The conversion would not be as simple as many might think. The Jabiru elevator has only a poofteenth of down movement. The gear legs might need beefing up with a cross member under the fuse.

Bruce it was on an old school aircraft that had done heaps of work. The inner bolt of the RH u/c leg broke as I touched down on a bumpy patch of grass. The other two bolts held, but as the leg folded up the right wingtip hit the ground and slid a few metres. The left main and nose wheel described a nice arc to the right and we came to a gently stop at a bit of an angle. No drama.After a long walk to get some tools and and new bolt I put the seat cushion and the wingtip on my head while the bolt was replaced. About ten minutes work. Superficial damage to the wingtip gelcoat only.

Just love fibreglass aeroplanes, and the Jab in particular!

In fact, the original 1600-engined LSA55 was even lighter in the nose and the mains where marginal for position. One one occasion, following an extended set of test flights, Rod Stiff offered the test pilot the opportunity to 'take it for a bit of a holiday' - which he gratefully accepted, packed his wife and their toothbrushes and a change of undies and other clothes ( there isn't room for much more aft in an LSA55..) and headed for the Whitsundays. First refueling stop, he filled up (the 55-litre tank, not the later 65-litre), hopped in, reached back to stow the small refueling jerry-can ( steel in those days), and the wee thing sat up and begged, very gently. Moved his arm forward, and it settled back onto the nosewheel.. I suspect Rod slightly changed the main leg profile..

(Just as a side-note, and of absolutely NO relevance to this thread: when flying along beside one Whitsunday Island, they saw a Great White cruising along - and were amazed and slightly horrified, to note that not only was it almost as long as the fuselage shadow of the Jab, but its pectoral fin spread was not insignificant compared to the wing shadow!)

So, back on topic... it only took a relatively minor change to the main legs moulds to bring the point of tyre static contact forward of the c/g. (remember, that it already is changed forward with the tail on the ground.. motorcyclists who know the rake and trail effect on the front wheel of changing the swing-arm static height will understand).

AFAIK, Jabiru have only ever offered factory parts to change to a tail-wheel configuration for the LSA55. I'm not at all sure that they haven't missed out on an opportunity to create with the J170 and a sophisticated application of VGs - as on the Seabird Seeker - quite a competent STOL version of the Jab. as a tail-wheel aircraft. Rod Stiff: if you are listening - you know who to contract to get there..

Fair enough - hard test, can't argue with the result.

My apologies - you were referring to the ATSB report on the Cirrus, I was thinking the NTSB report on the Sport Cruiser.

It's not productive to enter the debate about whether Cirrus aircraft are even remotely aerodynamically safe, since the first and only option in a spin situation is pulling the BRS, their accident record speaks for itself.

However, LSA aircraft are SUPPOSED to be spin-recoverable by 'normal' recovery techniques.

Is this a typo? 'Rudders neutral?'

Perhaps I have missed something, but from my reading of this accident, it was stated that 'ailerons neutral, right rudder applied'. That is my understanding of a 'normal' spin recovery (stick forward, opposite rudder to the direction of spin, ailerons neutral).

It was what I was trained to do on gliders and always worked; I could not think of how many times I have used the 'kick it opposite, stick forward, centre the ailerons' when I could feel the glider dropping into an incipient spin when in a rough thermal. It becomes a 'muscle memory' response when you are clawing for height, you don't even think about it ( other than to curse the loss of maybe 100 feet and needing to re-centre the thermal..) When in a close gaggle of other gliders in the same thermal, you can't look at your instruments, you watch the others around you and rely on the feeling you get through the stick, your feet, and the seat of your pants. AND - you rely on those above you also being fully-competent to NOT lose control - and those below you rely on you..

The CAW Sports Cruiser had one of the worst accident records in the USA survey reproduced at: http://www.jabiru.net.au/images/The%20Aviation%20Consumer%20-%20LSA%20Accidents.pdf

Worst for fatals, and Bristela designs (CAW and Evektor) were in the top three in every accident category. So far out on the right-hand side of the Bell curve for 'dangerous' that it is not even vaguely representative of the general level of safety for LSA-class aircraft. Should it be a wonder that Piper got out of being the distributor for a Bristela design after selling 54 aircraft?

However, what relevance is this to the thread topic?

I would suggest, that the relevance is: if the aircraft you fly (or are intending to fly) has markedly different characteristics to anything on which you have learned spin recovery ( or incipient spin recovery), then you should NOT assume that your training will suffice. I suggest that someone like djp has the expertise to properly comment on this, ( since I do NOT), but I suspect that having been trained tor spin recovery on, say, a Victa would not be sufficient to guarantee that if stepping into a Chipmunk - let alone a Pitts S12 - you could be assured that your training would help you.

As a side-note: the ASTM standard requires that a 'conventional' spin recovery will be sufficient: if that is NOT so for an ASTM certified aircraft, then I believe the manufacturer/designer has some very, very seriously important legal questions to answer.

Damn, my memory is not what is used to be ( I think..) Yep that was the one. I suspect the Mobil fuel was delivered to many aircraft using BP carnets

And a new, more efficient Flux Capacitor.

With all due respect to the work that must have been put in to making that J230 conversion, I wonder about the engineering.

The (relatively few) Jabs. that have been 'factory-equipment' changed to tail-dragger, utilised main gear that attached to the standard attachment points, just with a forward rake on the 'glass legs. The Jab. design was intended for tricycle gear, and the major bulkhead behind the occupants shoulders takes the form of a 'hoop' that transfers the rear spar load, the lift strut load, and the main gear load in a very effective structural design, which incorporates the occupant seat structure for added stiffness. Then, you have the front carry-through web and the 'A-pillars - very hefty 'glass members - down to the firewall, off which mounts the engine and the noseleg, and a central spine structure that completes the occupant safety capsule.

It is a complex design, and it has been proven many, many times to provide one of the best occupant safety capsules for this class of aircraft. The U/C attachment on that 230, probably cannot replicate the force conditions of the original design. If it does, then I take my hat off to the builder.

U/C design is a major part of occupant safety. If you watch the 'drop test' videos that Jabiru has on its web-site, you will see the extreme forces that are resisted, with the reaction to those forces being taken out by the deflection of the legs. What you DON'T see, is the cumulative effect of leg-spring and tyre deflection, but it's all been calculated into the test regime.

IF any component of the U/C fails prematurely and drops the fuselage onto the ground with excessive force, the likely result is at best, paraplegia. I guess it's a personal decision as to whether you want to get better performance, or be able to walk if a landing goes pear-shaped. Just personally, I'd be happier to be able to get out and kick the damn thing for not having gotten me to the accident sooner..

When the debate about Jabiru engine reliability was raging on here, pretty much anybody who suggested that 'improper' fuel for those engines should be looked at, was ridiculed by the self-professed experts.

Jabiru engines were originally designed ( and certificated under JAR22H) to run on 100LL. I think this thread has shown up, that using MOGAS in its variant forms is fraught with problems of supply, specification reliability, and age. Jabiru may have shot itself in the foot by allowing the use of Mogas at all - though it did the correct thing prima facie and reduced the compression ratio to allow the use of 95 RON Mogas.

Those with the knowledge of detonation, know that that condition is the likely primary cause of the Jabiru through-bolt failures ( though there is a design issue there as well, that is fairly sophisticated to explain, but without detonation would NOT have been an issue.) The early LSA55s with the 2200 engine running on 100LL never displayed the self-destructive characteristics of later variants.

The BP fuel contamination of Avgas hugely affected the GA fleet and cost millions of $$ to remediate. In some cases, entire fuel systems from (and including) the tanks onwards had to be replaced. GA operates under a far more stringent regime than Rec. Av.

Nev has raised a very, very cogent point. Of all the fuel specifications, 100LL and 95 RON ULP without ethanol, are the most stable and least aggressive of the fuels we can buy,

Australia has perhaps the worst reliability for 'delivered' fuel specification of practically any 'developed' nation. That is why both Japanese and European car (and motorcycle) engines for sale in Australia are de-rated by comparison to their home market specification. All we can say with certainty about our fuel quality, is that it is likely to be crap.

Jabs, and I suspect many other ultralights, utilise / utilised tanks ( if epoxy-resin glass), fuel pumps and fuel lines which are NOT suitable for use with any fuel containing ethanol or aromatics. Many metal tanks relied on 'sloshing' compounds for sealing that are attacked by aromatics and possibly ethanol. Of course, Jabiru's aren't the only aircraft to use epoxy tanks, simple Facit fuel pumps or fuel lines that are NOT rated for aromatics / ethanol.

But here's another interesting fact, for those who may feel relaxed that they have a Rotax. BOTH Jabirus and Rotax 912-series carburetored engines use the same Bing carby - and the carby-bowl floats don't tolerate ethanol or aromatics. I believe Rotax have fairly recently changed over to the 'grey' floats that do, I don't know whether Jabiru have also done so. Some BMW bikes that use the same carby ( the 64/94 series) have changed recently, and that avenue is the most likely source of (expensive!!) change-over parts.

For any IC-engined aircraft that relies on its engine for motivation, fuel delivery quality is a critical issue. The only aircraft that will reliability fly irrespective of the fuel available, is a glider... or electric-powered. I think diesel-powered IC engines may be more tolerant, but I don't know of any in the Recreational aircraft regime.

You wouldn't expect a prime athlete to necessarily be able to perform at her/his best after eating a load of cr@p food. Why, then, would you expect your aero-engine - that is a highly-stressed device on a power/weight basis - to perform to expectations if you throw it a load of cr@p fuel?

With the greatest respect to all the people who have given most useful and considered advice on this thread, and stating upfront that my power flying XC experience is almost zero, but I have a few decent XC flights in gliders to my credit- many years ago, way before GPS etc.

For planning a glider XC flight, in those days anyway, you basically made a note of the general track heading to the major waypoints ( either for a triangle flight or an out-and-return.) A glider has bugger-all space for map referencing en-route. So, your 'tracking' would be by visual reference: release from the tow, roll onto the required heading, note some physical feature on track, and then fly to get over that. When over it, roll out onto heading again and pick the next physical feature on-track, rinse and repeat..

In a glider, your primary concerns are to head for lift and avoid sink, with an increasing concern the lower you got, for keeping outlanding sites within glide distance. At 1K feet AGL, you abandoned the flight and headed for a safe landing site - and only modified that plan if you hit a really, really strong thermal almost immediately. Been there, lost a Diamond Distance ( 300K to a Goal) flight by about 3ks. Bugger.

In a glider, 'diversions' are weather-dependent. I've been WAY out of range for a planned return to base, had a cold-front roar in below me, had to turn and run like buggery for home sitting on top of wild IMC conditions and trying to balance my necessary speed and therefore descent rate vs. the front height. Ended up surfing the rising air ahead of the front into Narromine.. Got there, ended up soaked as we pulled the Libelle back to the hangar when that front hit.

With an engine to provide the motive power, rather than kinetic energy, should a diversion be such a drama? - provided you make the decision to divert before it is swamped upon you?

I look at the electronic aids available to us nowadays. It seems to me - based upon only what I can learn from on-line resources - that with a combination of something like OzRunways and the BOM radar information overlaid on that, you should be able to anticipate the necessity to divert well in advance of it 'happening' to you.

And what do people think about the Xavion application? Description – Xavion

I have no experience of flying IMC as the PIC ( but have flown into Tullamarine in the RHS in IMC in a Cherokee 6, breaking out of the cloud base at less than 500 feet, centred on the runway - thank you, electronics.) I HAVE had experience of running into Ulladulla harbour in a howling storm navigating totally blind to a necessary +/- 50 feet or so on the radar.

I am of the opinion that being forced to rely on paper-based navigation resources, in this day and age, is akin to being forced to demonstrate competency in Morse Code for communications. Commercial operations -with their vastly higher risk - rely on computer-controlled take-off and landing profiles, with the pilots being there mostly for 'out-of-condition' corrections. That's why those pilots are paid large salaries: to be the agent over-riding the electronics when it goes pear-shaped. I would not have it any other way.

HOWEVER: a diversion SHOULD be a reaction to something less than an emergency. Provided that one has sufficient back-up in one's electronic flight aids, I don't see why utilising such aids should not be acceptably safe flying.

A family member did the investigation into the BP Avgas contamination ( was awarded a medal by AOPA for his work on sorting out how to remediate that..)

One of the things he found ( there is an article some years ago in Sports Pilot about it) was that when refineries change from producing one category of fuel top another, there is often hundreds of litres of the 'old' specification still in the delivery lines. What you think is PULP, may not be it at all.

Avgas is the ONLY fuel that reliably meets the specification ( provided it isn't contaminated).

I know about a series of industry tests that were conducted following fuel quality issues - some of the results were alarming.I only buy fuel from Shell these days.

A mate of mine was the manager of the Shell refinery at Clyde in Sydney. He told me with glee one day about a new apprentice there, who told him that the Shell premium was nowhere near as good as the BP premium that came from the BP terminal next door. My mate told him,: 'well, you buy the BP stuff, then, laddie' - knowing that the BP fuel was delivered to the terminal via a pipeline direct from the Shell refinery..

This thread has, frankly, degenerated into a squabbling brawl with about as much relevance to the vast, vast majority of recreational aviators as a screaming match over who owns the sandpit by a kindergarten group of ADD 'special needs' five-year olds.. Any reasonable person not having any connection with recreational aviation, would come to the conclusion that recreational aviators are a mob of self-obsessed social misfits.

Those who have followed the travails of RAA over many years, and the political ( and commercial) machinations over the past several years, will recognise the agendas of many of the posters here. I won't even suggest who those may be, for the various protagonists, because those who care enough to keep informed, know them and know them well.

However, it is an incontrovertible fact that the vast, vast majority of RAA members do not give a fur-lined intercontinental flying F$ck about the 'politics'; they simply want to be able to fly, legally. They want to be able to pay their annual fees, and therefore be able to get in their aircraft and fly.

I count myself as one of those, and though I am not a member of RAA at the moment, it is where I will go when my aircraft is back on the Register. There is no alternative - despite all the noise made now about 12 months ago, of an alternative coming into being, but that has not happened and history says it may never happen - the alternative has had many false starts and promised much that has never occurred. I know a lame dog when I see one, and I won't be putting my aviating into a chimera.

For me, the bottom line to all of the debate in this thread is: even if there have been 'irregular' circumstances, what harm has that done to me? ( taking the hypothetical position that I was a member of RAA).

I don't see it.

If I was a losing candidate in this election I would feel justified in calling this election a farce.The RAA needs to count the votes received before the original deadline separate to those received afterwards.

 

I find it spurious, that a handful of late ballots, and its only a handful, can be used to justify this action when the vast majority have received their ballots within the original time frame.

 

All this delay has done has given some candidates extra time to campaign.

Your comment is complete, utter, and demonstrable organic fertiliser. Show me where I am wrong..

I am starting to feel like Balaam and goldulph is my "If the goal posts need to be moved to get the "right result" then move them" donkeyI suspect that a very very low turn out for the vote isn't going to be fixed by extending the deadline

Just POSSIBLY, the low voter turn-out is an indication that the vast majority of RAA members have no problem with the management of RAA and find it satisfactory to keep them happily flying.

I see plenty of whinging and bitching from people about RAA management, decisions and costs - led by a cabal who seek to make a business ( and therefore profit) from providing compliance services to the recreational aviation community. Yet - I wonder how many of those spend the same amount of time, effort and possibly money into combating the impositions placed upon them by the authorities who register their cars?

It costs around $1k to register anything these days, even if you only drive it for a few k's a year. Your 'vintage' car toy - that you drive maybe 200ks a year, in a club rally? Your 'track-day' Lotus that does even less, and is nothing but a sports toy? Your Ducati Desmosedici RR - a $US 72K track-weapon, that is utterly impracticable as road-going transport, but needs to be registered to ride to the track for your fun.

You can bitch all you want about RAA - but RAA is a necessary, by CASA decree using its legislative authority - agent for the operation of our class of aircraft and the number of hours flown per year by recreational aircraft says that service is in considerable demand.

Assuming that there are around 7500 members of RAA, then on here, there are around 15 disgruntled members. That equates, I think, to about .002% of RAA membership. Or, in less precise terms, a flea-bite on the backside of an elephant.

APN: I flew SGO - the one in this video:

from the RHS, with the CASA test pilot and the guy who did the aerodynamics as the PIC. I am no experienced power pilot; my experience is almost exclusively gliders. I've had some 'interesting' moments in gliders.

We went out over Hervey Bay in SGO, and the PIC handed it over to me and told me to 'try it out'. Now, the last power aircraft I had tried, was a Cherokee 6, 20 years previously, taking off from a bush strip... I was not exactly good at it.

After I had done the clearing turn, I tried progressively to push it harder.. it was delightful to fly but my limits were evidently way below those of the thing. So after about 15 minutes, he took over and demonstrated what it could really do.

I have flown beside this guy for nearly 50 years - he's a family member - and I trust him. He doesn't grandstand. He's an ex-Glider Instructor, ex-Tuggie, and for a period, a DoT aircraft crash investigator. Never bent an aircraft.

If you've ever been in a car with a major Rallye driver on the dirt, you would know the sensation of mildly screaming to yourself 'OH SH1T, we're going to die', and pushing your feet through the floor. The Seeker simply assumed, un-perturbed, situations which I just KNEW would result in serious consequences, and sailed on. He wasn't even pushing its envelope!

With all due respect to Peter Garrett, who did a brief test report on the Seeker, and who is one of the most experienced pilots on the planet, I believe - the Seeker simply does things to a level you would not normally even consider broaching.

And, Australia has lost it as an indigenous manufacturer. Poor fellow, my country.

He obviously has vested interest. Gandolph who are you. The thing with anonymity on forums such as this is people can push any barrow they wish with impunity.

I am not a current member of RAA, so by the forum rules, I cannot comment on its performance. Fair enough, those are the rules and I accept that I must abide by them. Those rules are entirely the prerogative of Ian Baker and the value of the site for the exchange of information and opinion is great to our community. Ian Rules - OK?

BUT, does it matter WHO is saying things, rather than the content of what they are saying? I can easily think of many, many posters here who use nom-de-plumes, and whose input is of great value. Here's a few: Facthunter; djpacro, HITC - and that just scratches the surface.

Forum members are generally intelligent people ( though we've had /have a few who are somewhat outside that envelope), and they can recognise 'vested interests' readily.

Personally, I look at the quality of the commentary rather than the persona of the contributor. I admit that there are some who almost by history, are on my list of 'ignore' forum members, they just irritate me and reading their stuff is inevitably a waste of life.. But that has nothing to do with whether they use a non-de-plume or a (possibly - do we know?) actual name.

Somebody here mentioned angle of attack being critical and I agree with that. They also said that it was dependent upom the angle of the stick, which I also agree with. What I don't understand is how can I know what the stick location is. I have flown several different aircraft over a few years and one of those for 15 plus years, but I still cannot tell where the stick is accurately enough to say when the stall will occur. I have always enjoyed slow flight, just waffling along with the nose in the air and feeling what is happening, but stick position is just beyond my capabilities.Can anyone else honestly say that they know exactly where to position the stick to be just above the stall?

For example, with about 50% power-on, in a Seabird Seeker you can fly around happily with the stick on the aft limit and 15 degrees of yaw at just above the stall speed FOR THAT POWER SETTING and turn on aileron and rudder as you wish, it was designed that way for its particular mission. I know, I've done it - and it felt weird to DO it, but the aerodynamics ( extremely clever application of VGs) unloads the elevators at just above the stall, so you can haul it back and putter along in complete confidence. The FAA chief test pilot who put the Seeker through its paces, reported back that it had 'possibly the most benign stall of any aircraft I have ever flown', and recommended to the FAA that they approach the guy who did the aerodynamics to instruct them in how to design the use of vg's to achieve that.

It's not that you don't have enough elevator power to actually stall a Seeker - it's that it has been fine-tuned so that the downwash off the wings plus the prop. blast at medium power combine to unload the elevators exactly enough to keep the thing flying happily. It took several years of development to get there! Amongst which, I believe something in the order of 120 spin-tests - some of which went to more than 90 degrees of bank....

Turbs, you old scallywag! If you are going to quote the constitution you should QUOTE it, not paraphrase itYou said:

 

The constitution says: "34.4 Subject to the Corporations Act, the Directors may from time to time determine the process by which Directors shall be elected and re-elected by the Members in General Meeting. Any voting method employed for the purpose of electing Directors shall be consistent with those methods accepted by the Australian Electoral Commission or an equivalent body." The additional emphasis has been added by me for clarity.

Give Turbs a break. He was just spicing up the conversation here, no need to be insalting.

A truly horrible result, and I join with everybody in hoping for the best for all concerned.

I will not be drawn into any discussion of who is the Fawlty party.