Weight restricted MTOW

[DonRamsay]

Same thinking says difference between 45 and 48 isnt much either and that raises the MTOW of a large portion of the EXISTING RAA fleet

Then we get back to the "There has to be a limit" argument. No doubt the 45 knots is an arbitrary number best described as "a slow stall speed". The aim of course is to keep the workload on the recreational, part-time, amateur pilot - low.

They could just as easily have chosen 40 kts or 50 kts. I would defy anyone to pick the difference between 45 and 50 knots. But you can tell the difference between 40 and 50 knots, I think.

 

Might be easier to modify the design of the wings/flaps to achieve 45 knots (new aircraft). Retro-fitting a redesigned wing and flaps might be a bit expensive for existing aircraft.

 

And of course, stall speed is only one aspect there is, more importantly, the G force handling and Vne/flutter issues.

 

 

[facthunter]

Landing speed is a real factor, to consider. STOL or very low wing loading types are not nice in gusty conditions. 45 knots is not a bad speed and you can lower stall speeds a few ways. VG's slots slats and flaps. Flaps also let you see more over the nose. Cessna high wings are a good example of effective flaps which make judgement of a forced landing a lot easier than most others. A slippery (fast) plane is not the go for outlanding, neither are small wheels. I would rather see the stall speed be not raised (much) and less antipathy to the weight increase. More weight has cost and safety benefits that should be considered in "calm" way. We didn't come down to our weight. We just got stuck with it in a fairly arbitrary way. F= M x V squared. V is the big consideration. The mass might even help the deceleration to be less as you will take a bit longer to stop. Nev

 

 

[JabiruJoe]

"I envisage building an organisation which revolves

 

around trust. One where we trust our instructors to do

 

the right thing and train people properly. One where we

 

trust pilots and maintainers to do the right thing. And if they

 

don’t, the answer isn’t to bring control back into the offices of

 

RAAus. The answer is to understand why bad decisions were made

 

and work to correct them"

 

That is a quote from the CEO in Sport Pilot. Trust to do the right thing and if not correct the decision. Time to correct this one.

 

 

[turboplanner]

He's bloody dreaming if he said that; it says sue me [the members], because I won't step up and self-administer, I'm going to trust others to self-manage.

 

And that would go back to what I was saying a year or so ago - the CFIs become the people to sue.

 

Compare that attitude to the statement by Worksafe Victoria to a risk 24 times lower.

 

 

[jetjr]

So RAA should head down same path a CASA? Thats working well.... actually your one of the very few think it is.

 

Trust is totally absent, operators hide and lie about things and avoid contact with CASA. Is that a good outcome?

 

evidence seems to say where other approaches are taken theres a better real safety outcome.

 

You seem to think RAA have some power of police or resources to carry it out.

 

That quote is a proactive approach which most are crying out for.

 

Workcover would be an example of where heavy regulation ends up, large majority hide and cover up problems so as not to let the attack dogs know bout it.

 

Forced to spend money chasing tiny risks and it becomes an exercise in looking like your acting safely. Interestingly some states Workcover is partially funded by fines and charges they impose. Its a destructive setup.

 

Costs increase to a point where businesses not absurdly profitable cease to exist or take on massive risk hiring people. And so they stop hiring.

 

Manufacturing and mining are good examples. As soon as these costs cant be supported by customers they wind down.

 

Fitting ROPS to ATV is a clear safety measure a long time coming. Workcover have not yet banned kids from driving them.

 

 

[turboplanner]

So RAA should head down same path a CASA? Thats working well.... actually your one of the very few think it is.Trust is totally absent, operators hide and lie about things and avoid contact with CASA. Is that a good outcome?

evidence seems to say where other approaches are taken theres a better real safety outcome.

If you don't understand these things, better to go off and get some advice before just confusing people.

RAA should NOT head down the same path as CASA. CASA is a government regulator which still has to operate prescriptively in some areas, and pay out on lilability

 

RAA is one of five or six groups who are free to operate their hobbies provided they self-administer

 

Administer here in broad terms means "manage" and "manage" here in a very broad term means "you're responsible for your own safety actions unless you let the ball drop, and then we'll prescribe something to make it safe"

 

I'm not taking CASA's side, I'm just pointing out to people who don't want any rules, particularly any CASA rules, that you're up the wrong gum tree, and thousands of other pilots don't have problems.

 

You seem to think RAA have some power of police or resources to carry it out.

No, I'm not; but RAA has the power to expand its Constitution to manage its affairs, and that hasn't been done.

RAA optentiall has 9,000 resources, and we know most will not step up, but there are plenty out there who would volunteer if asked to carry out audit functions on (a) Specification compliance, and compliance generally, and (b) training, skills and behaviour

 

Worksafe is a separate corporation from Government in Victoria, but operates;

 

Go and check the very short statement Worksafe Victoria made on rollover protection; just one sentence, no prescription, but so powerful legally that every operator in the state would be stupid not to fit rollover protection.

 

RAA potentially has the same power as that, just that the members have not been made aware of it except on this site.

 

That would be prescriptive, so why would you expect to see something like that happen in the 21st Century?

[facthunter]

Quad bikes and trikes are extremely dangerous vehicles. A roll cage doesn't do much unless an effective seat belt is used. Where do you stop with all this? Build everything to be idiot proof is a self defeating exercise. Eventually the machine becomes unworkable in it's original use. Nev

 

 

[coljones]

Quad bikes and trikes are extremely dangerous vehicles. A roll cage doesn't do much unless an effective seat belt is used. Where do you stop with all this? Build everything to be idiot proof is a self defeating exercise. Eventually the machine becomes unworkable in it's original use. Nev

If nothing it might impress on parents that the quads and trikes are deadly and that they should lock away the keys and exercise a higher degree of supervision about their use. We have adults around the city (and country) who buy their kids mini motor bikes and let them loose on roads, footpaths and in parks

 

 

[turboplanner]

Quad bikes and trikes are extremely dangerous vehicles.

Nationally in 2015 15 people died out of 270,000 on Quad bikes

RA aircraft had twenty four times the rate at approx 12 out of 9,000

 

If the press take on board the constant complaints about reporting "Cessna" crashes, stand by for some focus and attention.

 

A roll cage doesn't do much unless an effective seat belt is used. Where do you stop with all this? Build everything to be idiot proof is a self defeating exercise. Eventually the machine becomes unworkable in it's original use. Nev

The research over the past five years or so showed that quad bikes fitted with crush protection devices had trauma around 5% of the "normal" frame free bikes.

I agree that top side bars without seat belts can allow someone to slide down the seat and be crushed by the bar, but for some reason, maybe the crush injuries being from back flips, or the net weight at the side bar having enough leverage distance from the tyre base that serious injuries aren't occurring, and seat belts were not mentioned in the WorkSafe declaration. Doesn't stop people fitting them of course, but a lot of the farm operations require a quick grab of an animal from the seat, and a quick jump to close a gate, which is one of the reasons they are preferred over utes.

 

In fact this has been quite a clever move by the Victorian Government.

 

They mandated Roll Over Protection Systems on tractors at a cost of $700.00 to $1,000.00, and while every new tractor had one fitted, mant farmers with existing farmers used the "catch me first" method and didn't fit them.

 

That meant that for the idea to be effective the government had to go onto all the farms and prosecute those who hadn't fitted them, and that was too costly. The government was also responsible for the safety of the design.

 

That's the prescriptive system in action.

 

All the CPD action took was for WorkSafe to state: "WorkSafe has reviewed its strategy and has accepted that a roll-over protection device is an appropriate means of reducing risks when quad bikes are used in workplaces."

 

The government doesn't have to make it compulsory; they don't have to design it; they don't have the cost of inspecting any farms.

 

They just established a new standard, and now there's a standard there farmers can be advised not to use their quad bikes until they have a CPD fitted (for around $700). If the farmer ignores that advice then he faces prosecution and damages payout when an accident occurs.

 

This is much more powerful than the previous prescriptive method for tractors, eliminates all the paperwork, and all the costs are borne by the people involved.

 

Now you might say "Well what about the recreational quad bikes"

 

When the first fatal crash occurs, the Worksafe standard will be shown to the person responsible, and he will be asked if he had an equivalent risk management standard in place. If he doesn't he's looking at a big pay out.

 

 

[kasper]

Nationally in 2015 15 people died out of 270,000 on Quad bikesRA aircraft had twenty four times the rate at approx 12 out of 9,000

If the press take on board the constant complaints about reporting "Cessna" crashes, stand by for some focus and attention.

 

The research over the past five years or so showed that quad bikes fitted with crush protection devices had trauma around 5% of the "normal" frame free bikes.

 

I agree that top side bars without seat belts can allow someone to slide down the seat and be crushed by the bar, but for some reason, maybe the crush injuries being from back flips, or the net weight at the side bar having enough leverage distance from the tyre base that serious injuries aren't occurring, and seat belts were not mentioned in the WorkSafe declaration. Doesn't stop people fitting them of course, but a lot of the farm operations require a quick grab of an animal from the seat, and a quick jump to close a gate, which is one of the reasons they are preferred over utes.

 

In fact this has been quite a clever move by the Victorian Government.

 

They mandated Roll Over Protection Systems on tractors at a cost of $700.00 to $1,000.00, and while every new tractor had one fitted, mant farmers with existing farmers used the "catch me first" method and didn't fit them.

 

That meant that for the idea to be effective the government had to go onto all the farms and prosecute those who hadn't fitted them, and that was too costly. The government was also responsible for the safety of the design.

 

That's the prescriptive system in action.

 

All the CPD action took was for WorkSafe to state: "WorkSafe has reviewed its strategy and has accepted that a roll-over protection device is an appropriate means of reducing risks when quad bikes are used in workplaces."

 

The government doesn't have to make it compulsory; they don't have to design it; they don't have the cost of inspecting any farms.

 

They just established a new standard, and now there's a standard there farmers can be advised not to use their quad bikes until they have a CPD fitted (for around $700). If the farmer ignores that advice then he faces prosecution and damages payout when an accident occurs.

 

This is much more powerful than the previous prescriptive method for tractors, eliminates all the paperwork, and all the costs are borne by the people involved.

 

Now you might say "Well what about the recreational quad bikes"

 

When the first fatal crash occurs, the Worksafe standard will be shown to the person responsible, and he will be asked if he had an equivalent risk management standard in place. If he doesn't he's looking at a big pay out.

And from QuadWatch (I assume you are using their stats) that was DEATHS:

21 in 2015,

 

15 in 2014,

 

21 in 2013,

 

19 in 2012 and

 

20 in 2011

 

Average last 5 years - 19.2

 

From RAA the deaths I understand are running about slower than that.

 

And as accidents risk exposure is what is of concern comparisons of X deaths per participant or vehicle is not logical ... how about deaths per X hours of exposure ... I suspect that 12 deaths in RAA is a lower death rate per hour than quads ... and even then you are just looking at death - admittedly the ultimate in personal loss BUT how many injuries at lower than death per hour of operations does the quad expose you to compared to ultralights?

 

Personally still think a flying machine is less risky than a quad

 

 

[ave8rr]

The last few posts have nothing to do with the thread topic.

 

Back to topic Please.

 

 

[jetjr]

Rops for tractors were rebated for many years - operators got them nearly for free and generally had no effect on operations

 

You think Quads are dangerous, have a look at 2 wheel bikes off road and then Horses

 

 

[Head in the clouds]

...... The difference in stall speeds for the Sling at 600kg (43kts) and 700 kgs (44kts). Hardly a safety issue .....

This assertion doesn't quite agree with physics. I think you'll find the difference is more like 3.5kts, but don't take my word for it. Courtesy of the UK Light Aircraft Association I have attached a very handy spreadsheet which will calculate the stall speeds for you based on the information you enter. If you input the data for your own aircraft you can discover the real effects of varying weights on your stall speed.

 

It might surprise a few folks what their real stall speeds are but they'd be better suspecting the pitot/ASI setups than the spreadsheet. It's based on the correct formula i.e. Vs = √ 2 x M x nz/ρ x S x CL, where Vs is the stall speed, M is the aircraft mass in Newtons (weight in kg x 1g acceleration(9.8m/s)), nz is the load factor due to turning (to calculate the stall in a turn if required, otherwise enter zero for level flight), S is wing area in square metres and CL is the max lift co-efficient for the wing's airfoil.

 

.... I would defy anyone to pick the difference between 45 and 50 knots. But you can tell the difference between 40 and 50 knots, I think ....

OK, well based on the above spreadsheet the difference between you flying your Sling with 1 PoB and half fuel - or flying it with 2 PoB and enough fuel for MTOW at 600Kg would be about 3-4kts on the stall speed. I don't know about the Sling but I find there's a massively noticeable difference between half fuel and 1 PoB or 2 PoB and MTOW on any LSA types I've flown, and that's just 3-4kts difference at the stall.

 

I think this is what a lot of folks don't fully appreciate. I'm all for a weight increase on the basis of safer aircraft and cheaper aircraft by being able to use auto and motorcycle engine conversions and a higher percentage of commercial grade materials BUT I'm absolutely against simply having a weight increase purely on the basis that the airframes might be able to cope with it structurally, if it means that these aircraft would have a stall-speed increase to go with it. Try flying your aircraft light and then heavy as I described above, then consider what it would be like to fly it that much heavier again, because that's what the difference is to fly it at 700kg instead of 600kg, and it's much worse at 750kg ...

 

If the increased weight aircraft have to get bigger wings to keep the stall below 45kts then I can't see a problem, but there are two things that concern me with a stall speed that goes up with a weight increase.

 

The first is that the stall speed is based on an ISA standard atmosphere and so flying an LSA in the south in 15 degrees is a very different matter from flying one in the summer in the north. At 40 degrees and MTOW in Darwin you can sometimes wonder whether the runways are long enough and ground speed can be quite exciting while still being below flying speed ...

 

And - not meaning to offend anyone but from what you see on the flightline some weekends there are plenty of folks around who find our aircraft quite enough of a handful at 45kts stall speed let alone any faster. Of course there are plenty of our folks that can also easily handle a Spit or Mustang but we're all flying in the same category and if we increase the performance there will be plenty of the less able folks who just have to have, and can afford, the faster planes and I fear there might be an accompanying increase in 'statistics' to go with it.

 

There's really no need for a stall speed increase regardless of whether we have a weight increase. As someone mentioned above, just add VGs, slots, slats, and/or bigger or better flaps, or simply increase the wing area, depending on the 'mission' planned for the aircraft. My current 'DooMaw' build has much smaller wings than Don's Sling, and the same MTOW, but will stall about 7-8kts slower than his due to having various lift enhancing devices.

 

Stall Speed Calculator.xlsx

 

Stall Speed Calculator.xlsx

 

Stall Speed Calculator.xlsx

[facthunter]

Yes the 1 knot is not likely to be correct. Indicated stall speed may be anything. Generally the static source is to blame, and sometimes it is what is inside the fuselage, which makes the erroneous indications make it look that you are going slower than you are at slow speeds and faster than you are at high speeds. Average wind speeds at aerodromes have a bigger % effect on slower speeds than higher, and it is assumed you land into wind generally. Nev

 

Edited.. Clarification of static pressure effects. 10:31...

 

 

[JabiruJoe]

Can anybody who has an aircraft that is affected by the weight restricted MTOW please pm me so I can get an idea of how many aircraft are affected. It doesn't matter if you would support action or not, but a contact would be most helpful. Also, if you know of anybody who is not aware of this forum or conversaion, could you ask them to come to the site and pm me.thanks Jj

 

 

[turboplanner]

Brilliant HITC, I love seeing engineering data explained as clearly as this, it peels away the fluff. It allows us to understand that if we change something by x in one area there will be a result y in another.

 

I understand Don's view of the very small difference in speed, and you wouldn't pick the difference in speed, but once the effects of that speed are explained, I think may people would think twice about agitating for a slug that climbs like a snail, producing the half mile circuits that everyone complains about, doesn't respond so nicely to control inputs and so on.

 

 

[jetjr]

A majority part of RAA cant "add" or do anything much to their aircraft so its a moot point. Your only effecting homebuilts still owned by builder. Thats a rapidly decreasing portion of aircraft.

 

If a raised MTOW is only for new design and purchased aircraft, its not going to make much difference to many.

 

Working stall from tables isnt going to work too well either - (not doubting the numbers produced and its a good place to start) - as every individual air frame is different and as you said addition of VG etc can effect each one differently. Going to need be tested in flight and thats not easy or accurate.

 

If its a modification then thats going to place results outside data?

 

Bit of a stretch there TP, if thats what the extra weight did why would you carry it?

 

In many cases the same aircraft are out there now under different regs and dont suffer these results. You dont have to fly at higher MTOW.

 

Id have thought many want to carry extra fuel, thats a decreasing weight, in some cases around 20kg per hour. The first planned landing could be under old MTOW anyway.

 

 

[Head in the clouds]

..... Working stall from tables isnt going to work too well either - (not doubting the numbers produced and its a good place to start) - as every individual air frame is different and as you said addition of VG etc can effect each one differently. Going to need be tested in flight and thats not easy or accurate ....

Testing the stall speed inflight isn't very difficult at all, and it can be very accurate, if the elevator has sufficient authority to actually stall the mainplane, which many don't particularly power-off. It might be a bit of an effort to do it for just one aircraft but if there was a plan to test every aircraft, for example, or every new aircraft, then it wouldn't be at all hard to have a dedicated set of equipment made available for the purpose. All that's needed is an accurately calibrated ASI, a swivelling pitot to attach to the front of the existing pitot head and a trailing-cone static source. The last is the hardest to organise but there's no real reason it can't be arranged to be deployed from a small cable-drum (with weak link) lightly attached to the pax floor, and trailing out of a vent or similar. Provided it was properly guided through a fairlead at the tail it needn't present any hazard while deploying or retrieving. And corrections applied to the indicated result for the air density on the day.

 

BUT - that's totally unnecessary. The logical and much cheaper and 'fairer' process would be to provide all the evidence from the Lift Formula for any airframe. There are numerous software that will provide the CL Max for all standard airfoils and a very accurate CL Max for any non-standard foil simply by inputting the co-ordinates for the as-built wing. Factors can be applied for any particular airframe peculiarity and also for slots, slats and any type of flaps. I'd leave VGs out of the equation altogether since most aren't applied in any standard manner, and although they help to keep the flow attachment and detachment more predictable, they don't actually affect the CL (and hence stall speed) very much, they tend to have a greater effect on pitot error instead, due to the higher deck angle that people can become more confident with.

 

 

[kasper]

A majority part of RAA cant "add" or do anything much to their aircraft so its a moot point. Your only effecting homebuilts still owned by builder. Thats a rapidly decreasing portion of aircraft....clipped

In this answer you are implicitly accepting that 19 reg cannot be modded by the owner unless they are the original builder ... that was the view of some within RAA board and the Tech Manager ... it is NOT the current legal situation and unless/until CASA change the CAO to make it the legal position the number of aircraft STILL under the design control of the owner is ALL homebuilts under 95.10. 95.32 and 95.55 holding 10- 32- (soon to be 18- i believe) and 19- regn

 

 

[facthunter]

If they can't do mods they should/would be restricted to something like what private pilots can do. That's not in the spirit of this movement . Any one with half a brain would do what they are capable of and get help with anything else. No L2 or even beyond that is NOT across all repair /mod skills. 19 is a pretty restricted use class. Common sense. A true misnomer. Nev

 

 

[turboplanner]

Well given what you just said FH, how do you feel about one official forced landing due to a spark plug falling out?

 

 

[facthunter]

If they aren't tightened they overheat and can fall out. They usually slowly unscrew. I wouldn't be surprised if it went through the cowl.. LAME's aren't immune from failing to tighten things either. The owner is personally involved with the plane and is highly motivated to keep it safe as possible. It's just another job to anyone else, and people can get distracted. Don't work on a plane if someone starts talking to you..A non tightened sump drain would be more dangerous. Nev

 

 

[M61A1]

Well given what you just said FH, how do you feel about one official forced landing due to a spark plug falling out?

Assuming that they were flying over somewhere they could land or where they could glide to a place to land, and didn't botch the forced landing, one would hope that next time they remember to check their work. No problem, and if they weren't, well that's still their fault and no real concern of ours.

Most of our problem is there is a silly belief that for some reason we should as a society, stick our noses in in everything and save people from themselves.

 

Let it go. It works for pretty much every other species on the planet.

 

 

[facthunter]

A six cylinder engine would probably keep giving a little power, with one plug out. Nev

 

 

[jetjr]

In this answer you are implicitly accepting that 19 reg cannot be modded by the owner unless they are the original builder ... that was the view of some within RAA board and the Tech Manager ... it is NOT the current legal situation and unless/until CASA change the CAO to make it the legal position the number of aircraft STILL under the design control of the owner is ALL homebuilts under 95.10. 95.32 and 95.55 holding 10- 32- (soon to be 18- i believe) and 19- regn

Yes your right, and MARAP should help the others too.

 

CASA were quite prepared rewrite CAO if required, I was lead to believe and could yet. If we dont talk about it, it may be left alone..... MARAP is the new path for all. yay!

 

I also not sure people SHOULD be modifying aerodynamic issues with aircraft without deep thought. New wings?? Slats and flap mods could easily bring trouble.

 

Could be a market for upgrade kits?

 

600kg is there for whoever can make it work currently - possibly stretching capability of min stall speed to get there.

 

Then comes mostly LSA who have variants operating above this in VH reg - these aircraft cant be modified without factory approval. Quickly this is becoming largest part of RAA fleet.

 

There are some homebuilts in this space but not many I suspect.

 

So im thinking there isnt too many homebuilts around with higher capability and low enough stall speed that can upgrade.

 

BUT, raise/remove/replace stall speed and theres lots (inc E LSA) that can one way or another get a bit heavier.

 

Large Jabiru would be a fine candidate for 700kg. 48kts stall. Would also permit many RV and probably some C models too.