RAA Safety-Training-Compliance Coordinator appointed

[Dafydd Llewellyn]

When did the Thruster wing go into a wind tunnel? There was a change to the wingtip design but that came about from tuft testing. All structural testing was done at Kirrawee factory via normal loading methods. Never heard of full size wind tunnel testing tho. Could be wrong, lot of sneaky crap going on at that time.

I may be wrong re wind-tunnel - Newton may have done the work in flight - or a mixture of both. I think - but it's a long time ago and my memory may be faulty - that Newton used the 5 ft x 7 ft tunnel in the Syney University Engineering school, to do some pitching-moment tests on a section of wing, and thereby obtained a relationship between the pitching moment and the camber - and then used full-scale flight tests to establish the actual camber in various phases of flight, so he could deduce the full-size pitching moment for the purposes of the structural analysis. No we do not have anything equivalent to the NASA AMES tunnel; like the Brits, we have to make do with less extravagant facilities (like, firing chicken carcases at windscreens using a giant air gun to demonstrate birdstrike, rather than hanging the chicken carcass by a string and firing the front of the fuselage at it on a rocket sled.)

 

The CA22 Skyfox was a licence-built Kitfox III; it needed some 35 substantial engineering changes to reach a MINIMUM certification standard. I would certainly not hold it out as an example of good engineering art - merely, it did (eventually, after a lot of effort) reach an acceptable minimum standard against the requirement. Remember that the statutory airworthiness standards used for certification standards are MINIMUM standards - they do not guarantee excellence.

 

 

[facthunter]

It's an unusual airfoil section, but it doesn't have big trim changes with airspeed variation. The "on their own " ailerons work well even if structurally they are a bit suss. Having folding wings is a useful feature but not without it's problems. They weren't particularly cheap when new. Nev

 

 

[drifterdriver]

I recollect a figure of somewhere around $85k for a Gazelle with all the bells and whistles. I could be mistaken but I remember being knocked over by the price at the time.

 

 

[Guest Maj Millard]

Both the Skyfox and the Gazelle do fly great, and the Junkers type flaperons work well also. Fortunately the design has further mutated in the Eurofox, which is sort of everything the Skyfox should have been.

 

The cabin is larger, the landing gear looks indestructible, and the flaperons look like they are firmly attached to stay. Add some real nice European quality to the mix, and you have a great aircraft to carry on the line...........Maj...

 

 

[dazza 38]

Got to love the wide undercarriage on the TW Eurofox. I would to see one in the flesh.

 

Hi Nick, yup that 85 K sounds about right for a Gazelle back in the late nineties from memory. A Eurofox is not much more now 15 odd years later.

 

 

[Dafydd Llewellyn]

Both the Skyfox and the Gazelle do fly great, and the Junkers type flaperons work well also. Fortunately the design has further mutated in the Eurofox, which is sort of everything the Skyfox should have been.The cabin is larger, the landing gear looks indestructible, and the flaperons look like they are firmly attached to stay. Add some real nice European quality to the mix, and you have a great aircraft to carry on the line...........Maj...

Yes, well we're getting rather off the subject of this thread. However, the matters learned in the Skyfox certification were supplied to Kitfox (part of the licence deal) so we had some small part in improving the breed. The problem with the lift-strut carry-through was corrosion-assisted fatigue of a lousy bit of detail design; the certification basis was BCAR S preliminary issue, which did not require any fatigue-life analysis. This is one of the notable shortcomings of the "watered-down" design requirements; CAR 35 engineers such as Bill Whitney, Alan Kerr and myself, got called in well after the prototype was flying, and we only got to fix problems that prevented certification - the original designs were far from professional in standard. I approved a piece of reinforcement for that part of the structure after the excitement at Bribie Island. The prototype had some very serious problems, and these cost the original entrepreneur his shirt, by the time the worst of them had been fixed and certification achieved.

 

The message is, just because an aircraft type has achieved popularity as an experimental type, does NOT mean it's a good prospect to certificate and put into production.

 

 

[Guest Maj Millard]

Doesn't sound like jumping through all the Australian certification hoops is any guarantee either Daffydd, as demonstrated on the Skyfox, and with a few things I have experienced on the Storches in the field. The certification process also sent Nestor round the bend, and pretty much caused him to leave us for greener pastures . To complicate designs, and to make things more complex just to satisfy some magical standard does not guarantee anything, and certainly not reliability in my experience.........Maj...

 

 

[Dafydd Llewellyn]

Doesn't sound like jumping through all the Australian certification hoops is any guarantee either Daffydd, as demonstrated on the Skyfox, and with a few things I have experienced on the Storches in the field. The certification process also sent Nestor round the bend, and pretty much caused him to leave us for greener pastures . To complicate designs, and to make things more complex just to satisfy some magical standard does not guarantee anything, and certainly not reliability in my experience.........Maj...

Certification is a major task, and it needs to be "designed in" to the aircraft (as does compliance with the ASTM standard, for an LSA aircraft.) People like Nestor, Fisher, and the Skyfox fellow, who try to short-cut the process, always make it much harder than it need be - but it's no simple exercise, regardless. Either certification or the LSA path is a requirement for anybody to manufacture factory-built aircraft for sale to the market-place. It's not required for amateur-built. So it's not optional; you have to do it, or not, according to what kind of aircraft you want to build.

 

I have been talking about the safety system needs for RAAus in regard to factory-built aircraft, and for them either Type certification or LSA certification is required by law - so there's little point in dicussing whether or not it's desirable. So far, I've not come across any amateur-designed aircraft (and I do not count things like the Questair as amateur-designed) that did not have a serious design fault. I agree most of the factory -built stuff could stand to be better, but it also has to sell, so the market gets pretty much what it demands. The certification design standards are written in blood, so it's downright stupid to ignore them, even if certification is not required. However they deal with basic design, they do not demand brilliant design.

 

 

[facthunter]

A lot of stuff sells on looks rather than a good basic design. Final and necessary fatigue testing of the Dassault Mirage was only done at GAF at Fishermens bend Melbourne in the 60's? I remenmber going there when it was in the rig being pulled up and down for weeks. Cessna non strutted types are now finding structural wing faults ( Not due to corrosion.). Monitoring of high life (early production often with high use) requires aircraft have to be inspected. for developing faults. I flew Fokker Friendship aircraft when the american built (Fairchild ) had wing faults, and all F-27's had speed restrictions applied at the time. It's part of the scene but when it is a problem at the high end how do you cover the "simple" end. It's probable that the service life of most of our models is about 3,000 hours or less. Some designs lend them selves to effective inspection but many don't have access to vital parts. There's not much consistency in production so what may not be a problem with one build may appear as one in another quite early in it's life. Nev .

 

 

[Keith Page]

Hi Daffyd

 

You answered it.

 

""However they deal with basis design not brilliant design.""

 

What ever we design keep it simple and functional, because if we go for brillint design in one area there will be another area pulling up short.

 

This even applies to making a good chook house.

 

Regards,

 

Keith Page.

 

 

[Dafydd Llewellyn]

A lot of stuff sells on looks rather than a good basic design.

 

Yes - as George Markey was wont to say, "They only buy the paint".

 

Final and necessary fatigue testing of the Dassault Mirage was only done at GAF at Fishermens bend Melbourne in the 60's? I remenmber going there when it was in the rig being pulled up and down for weeks. Cessna non strutted types are now finding structural wing faults ( Not due to corrosion.). Monitoring of high life (early production often with high use) requires aircraft have to be inspected. for developing faults.

 

The CAR 3 design standard that applies to those old Cessnas did not include any fatigue life requirements. Neither do ANY of the simplified design standards for recreational aircraft. FAR 23 introduced them for GA aircraft for the first time, and it didn't get serious about it until the late 1980s. The logic was that the average private-owner aircraft seldom flies more than 100 hours/year - but this overlooks that training school aircraft may do ten times that per year. The intent was/is that when the problems show up, an AD can be issued to deal with it. So you are all test pilots, in a sense. If you want to know more about this subject, look at FAA AC 23.13A

 

There's not much consistency in production so what may not be a problem with one build may appear as one in another quite early in it's life. Nev .

 

That's the purpose of having Production Certificates (See CASR Part 21 subpart G)

 

What ever we design keep it simple and functional, because if we go for brillint design in one area there will be another area pulling up short.

 

This even applies to making a good chook house.

 

Yes, that's what Bill Whitney and I were after. You get long fatigue life by putting sufficient material there in the first place, to keep the stress levels down. That needs a bit more weight.

 

Finally, something people might consider, before arguing against Type certification: If you purchase a factory-built aircraft, do you want the factory to still be around when you needs a spare part? Or if you need to make a warranty claim? If you do, then the factory has to stay in business. That means, it has to (a) make a profit, and (b) avoid being sued for product liability. A Type Certificate and a Production Certificate are, nowadays, practical necessities as the most basic defence against product liability. Look at the horrible example of what product liability litigation did to the US GA aircraft manufacturers, and FFS stop being so utterly stupid.

 

 

[damkia]

RAA Safety-Training-Compliance Coordinator appointed

 

 

Perhaps this thread need a bit of a clean up and split?

 

 

[facthunter]

Agree with all that. I suggest that the weight limits we are restricted to, prevent sufficient strength being built into the basic structure, unless carbon fibre is employed and I don't believe that is where we should be going (in large numbers).

 

The Taylorcraft type of construction gives good basic flying characteristics with strength, cheap build with unsophisticated materials and cheap to homebuild, but it ends up at about 650 Kgs AUW. and can be almost everlasting ( with proper inspection.)

 

Anyhow have we had much of a problem with structural failure? Excluding Nosewheel assemblies which are a joke.

 

Are we going to get REAL improvements in safety or just compliance for the appearance of it.? Nev

 

 

[ahlocks]

Perhaps this thread need a bit of a clean up and split?

I was thinking more along the lines of lock off and delete but then again, I'm just about over the whole RAA thing these days...

 

 

[Guest SAJabiruflyer]

How could anyone work with a dictator that wanted it all his way and no other way. No democracy involved, therefore we had a board of ONE, and all other members could say or do nothing or vote as us members had indicated to them.

Again with the personal attacks.. sheesh. So if we get new Board Members, even if some Vocal Forumites come on the Board of RA-Aus, are they going to be attacked too? Where does it end? I have just returned from being outside where I made a head-sized dent in my brick wall from multiple applications of head against said wall. No, it didnt knock any sense into me.

 

Tiger - did you make any phone calls and perform the research to find out why our ex-President acted as he did? The results of doing such would make a reasonable man realise the realisation of the enormity of the situation, and the Emergency that required such action to be taken as Real and Needed. Really.

 

 

[Aerochute Kev]

I don't buy it. There is no reason that I can think of for a President to overrule the board and do what he likes, just because he thinks his way is the best way. The board members are our representatives, there to act on our behalf. If any decision remains at a stalemate, the obvious solution is to present the information (ALL of it) to the members at a general meeting and have the membership decide the resolution.

 

They have to remember that they are there to represent our views for the benefit of the organisation and its members, so why not seek advice from them in such a situation.

 

 

[terryc]

aerochute kev, for those that don't get it we must say it again and again, there is no situation that exists that requires anybody to step outside the guidelines of good governance . I agree with you when it comes to a stalemate go to the membership. It's not that hard.

 

 

[Guest Maj Millard]

Agree with all that. I suggest that the weight limits we are restricted to, prevent sufficient strength being built into the basic structure, unless carbon fibre is employed and I don't believe that is where we should be going (in large numbers).The Taylorcraft type of construction gives good basic flying characteristics with strength, cheap build with unsophisticated materials and cheap to homebuild, but it ends up at about 650 Kgs AUW. and can be almost everlasting ( with proper inspection.)

Anyhow have we had much of a problem with structural failure? Excluding Nosewheel assemblies which are a joke.

 

Are we going to get REAL improvements in safety or just compliance for the appearance of it.? Nev

The "Taylorcraft" type construction that you mention is proving to Be one of the longest lasting type construction methods employed. It is , simple , light, strong and easy to inspect and maintain. Many known classics employ it including all piper Cub types, Austers, Taylorcrafts of course and the Lightwings.

 

When looking at G loadings when designing, one must remember that a lighter plane is a stronger plane, and a heavier plane is a weaker plane. It is ultimately weight that piles on the Gs and breaks things...................Maj....

 

 

[AlfaRomeo]

Well, I have to say I found the aeronautical engineering discussions more interesting than the other stuff.

 

Probably a good time to rules a line under this poll as, after all this time, it is sitting at 50:50

 

I fear the result of this poll is clouded by what people thought they were voting for.

 

Few, I think, actually oppose a SMS or somebody to promote and control it.

 

Plenty, including the Board Majority, did not approve the gift to Myles.

 

I hope no clear thinking member would applaud the assumption of autocratic power and abandonment of good governance as a way of doing business.

 

The argument for "emergency" has been proven by the effluxion of time (and 20:20 hindsight) to have been, at least, an over-reaction.

 

All in all, an ugly example of poor governance.

 

Hopefully, it will not be quickly forgotten and it will never be repeated.

 

 

[Guest Maj Millard]

Alfa, There was no board 'majority' as you suggest, merely a 50/50 stalemate ..remember ?...............Maj...

 

 

[AlfaRomeo]

Not when it came to Myles appointment and not when it came to Ed's call for my way or the highway. The last one he only had the support of Middo and Caban - the other 7 opposed. That is not 50:50

 

 

[AVOCET]

The "Taylorcraft" type construction that you mention is proving to Be one of the longest lasting type construction methods employed. It is , simple , light, strong and easy to inspect and maintain. Many known classics employ it including all piper Cub types, Austers, Taylorcrafts of course and the Lightwings.When looking at G loadings when designing, one must remember that a lighter plane is a stronger plane, and a heavier plane is a weaker plane. It is ultimately weight that piles on the Gs and breaks things...................Maj....

Hi Maj. I like listening to you guys talking about the engineering & certification stuff ,

 

I owned for a while while I tidied up a and replaced what needed replacing a couple of early jabs , number 10 & 15 ,

 

15 had 7,600 hrs on the clock and is still going strong , it still didn't have the bulkhead behind the tank fitted , just the old cross brace, that used to detach from time to time.

 

I did it up to keep , as it was the one I went solo in , but had to sell to help finance the avocet ,

 

I don't have enough fingers and toes to do a count on how many engines it might have had , ( well maybe that's a bit exaggerated !!)

 

Cheers mike

 

 

[Dafydd Llewellyn]

The "Taylorcraft" type construction that you mention is proving to Be one of the longest lasting type construction methods employed. It is , simple , light, strong and easy to inspect and maintain. Many known classics employ it including all piper Cub types, Austers, Taylorcrafts of course and the Lightwings.When looking at G loadings when designing, one must remember that a lighter plane is a stronger plane, and a heavier plane is a weaker plane. It is ultimately weight that piles on the Gs and breaks things...................Maj....

Not that cheap, actually; look at the price of a new Super Cub. Did you know that a Drifter has nine times the parts count of a Jabiru?

 

 

[Guest Maj Millard]

Not that cheap, actually; look at the price of a new Super Cub. Did you know that a Drifter has nine times the parts count of a Jabiru?

Yes but Daffyd, most of those many parts on the Drifters have a habit of continuing to work........Maj... watch out !

 

 

[Oscar]

Yes but Daffyd, most of those many parts on the Drifters have a habit of continuing to work........Maj... watch out !

Oh, FFS, what parallel universe do you inhabit? The quality of construction on the Drifters, Thrusters etc. 'continues to work' because they are the aeronautical equivalent of billycarts. I've done extensive refurbishment on a Thruster and I would not put my children in a sailing dinghy out on the Bay with fittings of that quality. As George Markey - who was working in the same hangar at the time, said to me: 'it doesn't matter, because they're so slow, they don't generally manage to get to the scene of the accident when it happens'.

 

That's fine for people who are happy to tinker with their wires and bungee cords rather than go from Point A to Point B. If you have no more desire than to spend time on a weekend looking around a paddock from the ground while you fiddle with your aerial deckchair, so that you can spend 20 minutes looking at the paddock from an elevated position - well, good luck to you. I wish you well, and safe and happy flying. I ride a motorcycle for pleasure, so I understand the allure of 'just toddling along, enjoying the moment'.

 

However, a lot of RAA-class aircraft owners want to use their aircraft as a means to another end: visiting places that would be otherwise be denied them, perhaps engaging in their occupation. Their aircraft is not an end in itself - it is a tool to achieve the end they seek. It is not, for them, 'the journey', but the destination achieved that is important. They need to be assured that from the time of hitting the starter button to the time of shutting down, the aircraft has performed as expected.

 

It's the difference between owing a vintage car for the pleasure of tinkering with it, to traveling for the purpose of experiencing a new location. It's why the Toyota Camry is the world's best-selling motor vehicle vs. a Morgan Plus 4.

 

And it's why Jabiru have sold thousands of aircraft. How many Drifters are there on the register?