Airworthiness Alert,MTO Sport Gyro's

Murray Barker

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Airworthiness Alert from Australia for your information.
 

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I remember the early Air Command S/S with a shorter mast having the same problem's.

I hope the manufacturer is able to provide an easy fix.
 
Directive AD 2010.01

11. With immediate effect and until further notice ASRA members are the only persons permitted to be flown in MT Sport gyroplanes as passengers.

Alert AA 2010.01

12. With immediate effect and until further notice all ASRA members are required to undertake MT Sport-associated gyroplane operations mindful of the potential for damage of the kind detailed in paragraph 1 of this document.

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Not being familiar with OZ regulations, who are "ASRA members"?
 
ASRA is 'The Australian Sport Rotorcraft Association'. The governing body controlling Gyroplane operations in OZ.
 
Maybe????

Maybe????

Maybe a reduction of teeter amount. The RAF had the same problem BUT incorrectly insisted on 20 to 22 degrees of teeter and rear head movement. I would reduce the RAF teeter to 18 degrees as per Bensen by gluing approximately 1/8th" thick plastic material to the underneath of the hub bar where it touches the teeter stops. I would also limit the adjustable rear head movement to 18 degrees as per Bensen.

I have flown RAF down to 16 degrees of teeter and 17 degrees back stick. With an effective pre rotator teeter can possibly be reduced below what I have proven to be adequate.

Just a thought from my experiences.

Aussie Paul. :)
 
How can ASRA call for no possible rotor contact during rotor flap? Section T is tough, and only calls for that guarantee under "permissible" operating conditions. Is there any gyro that can't have a tail strike if you flap the rotors?
 
That's interesting. I wonder if the student didn't allow the rrpm to fall too much before he attempted another take-off. The ensuing blade flapping would have caused the observed damage. In this case I agree with Paul: I don't know of any gyro whose rotor wouldn't confer structural damage if it hits the teeter stop sufficiently hard.

I wonder if the slight but important difference in wording between the British Section T and the Australian ASRA standards is intentional or accidental.

But determining whether the clearance is sufficient or not shouldn't be such a hard thing to accomplish.

-- Chris.
 
Tail strike on the MTOSport has happened here at least a couple of times - once on a rough field take-off (see article in Autumn 09 Rotorcraft Magazine) and once when the stick was pulled back with less than 100 rpm on the rotor. When you see how close the rotor gets to the tail compared to the MT-03, you can understand it. I had understood that the m/f was looking at altering the profile of the rudder/fin to improve matters.
 
The rotor blades will hit the prop and tail on an MT Sport even without flapping.

With the rotor stationary, stick back and and hub bar on the stops the rotor intersects the prop and tail by a couple of inches.

There are 17 gyro's in the hanger where I fly from. Some factory built but mostly homebuilt, and all will stand some degree of flapping without hitting part of the structure.

Maybe we just build them correctly over here?


.
 
Murray, there are two separate issues. Intersection of the tail or the prop arc by the rotor which can happen during routine engine starting, beginning of prerotation, etc., is absolutely a problem, and needs to be addressed. RAF had a similar issue at one time.

But the ASRA clearance standard, as written, seems unreasonable, and hard to demonstrate in any event. It doesn't say, "some degree of flapping," it puts it as an absolute. If you flap the blades badly enough to distort their shape, I don't think there's a machine out there that doesn't risk having them hit the keel, the ground, or even the pilot directly.
 
To my thinking the onset of blade flap is when the gyro departs from 'normal operation'. In a departure from normal operating parameters or exceeding limits it can be expected that there would be bad consequences.

It does seem dangerous that contact can be made during intersection of the rotor and blade arcs on the ground

Onset of blade flap being the outer limit, the rotor should have 'adequate' clearance during normal operation. Adequate is a loose term. We heard, and used a minimum clearance of two inches for tip of prop, tail and ground clearance using the most limiting of those three.

Should popular or informed opinion suggest more I would be prepared to limit it to greater, with an eye to not compromising controlability
 
Was the welding between mast and horizontal frame checked ? This welding often cracks which could lead to a slightly backward bent mast resulting in the acc that happened in Australia
 

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Was the welding between mast and horizontal frame checked ? This welding often cracks which could lead to a slightly backward bent mast resulting in the acc that happened in Australia

Angelo,

as you know, Magnis now have to undergo an inspection every 50 hrs. for the same reason. Personally I have never seen this happen, so either I have never seen one old enough or it has something to do with how they are treated, in particular on landing.

Welding this crucial point has its pros and cons and recently the M/F has added additional supports to the mast, to reduce this cracking effect.

The ASRA report mentions nothing about cracks, so I guess this is just part of your "mission" to spill some dirt on the company (base on your truly bad experience).

No offence meant.

Kai.
 
Kai I know nothing about Angelo's truly bad experience however it would occur to me that had he had such an experience it would be natural for him to be concerned about this, and not just part of your "mission" to spill some dirt on the company

Safety is something that concerns us all. Any bad experience raises questions that we would all like to see explored and addressed.
 
If the mast is bent backwards (because of the failure of the welds) it would increase the clearance not decrease it. The mast is bent forward so if you are to bend it back it will be higher not lower, and move the rotor further away from the tail.

I own an Mt03 sport here in Australia and the AD is potentially distratrous as it will kill the resale value if there is no apparent fix coming. Who wants a two place machine that cant carry passengers.

I have been told from credible sources that when a static measurement was carried out on a late model MT03 sport as descibed by Murray Barker in the preceding posts the rotor blade comes in contact with the tail. I have a 18 month old model and the rotor does not touch the tail when doing the same measurement.

So hopefully the factory can explain what has happened, whether they have introduced a new head or change the stop setting in subsequent models and the fix can be relatively simple. If they fail to address this properly then the certifcate could be revoked here and we wont be able to fly our machines at all.

This should be ringing some alarm bells in the UK as the CAA might adopt the CASA recommendations as the standards between the countries are the same and ASRA are basically accusing the factory of not adhering to these standards.
 
Leigh,

this thread is not about mast cracks, which by itself is much more scary, than rotor strike on the ground.
As JAL states, one has nothing to do with the other.

Kai.
 
Well, it´s not any kind of "mission" on my side. I remembered a thread where construction-experts of this forum critizised mast constructions that are bent forward from the vertical giving enourmous stresses to the frame-materials in flight.

So if the mast is bent backwards eased by cracks this could make the 2 inches for prop-contact. The cracks i picted were detected just by chance and only 4 weeks after an official annual inspection by a German certified airworthiness inspector.

I also remember that an Autogyro-official back in 2004 warned me these mast-foot-cracks are a crucial problem on ELA-gyroplanes but so far did not hear something like that from ELA-gyroplanes.

It was just ONE idea among many that might explain the issue (or not)
 
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