Magni M14 down in Germany

[C. Beaty]

In this instance, Brian, you are correct. Torque reaction against the airframe is the same whether CLT or not.

The only way of removing torque reaction against the airframe is via contrarotating propellers or vanes in the propeller slipstream that straightens the corkscrew.

The tall tail of a Dominator removes most of the torque reaction and as a matter of speculation, most likely does the full span horizontal stabilizer of the Xenon.

Some of the Cierva direct control Autogiros used an inverted airfoil horizontal stabilizer on one side and an upright airfoil on the other. Others simply used large trim tabs set differentially.

Ron Heron has mentioned placing the main wheels of the LW on bathroom scales and setting horizontal tailplane differential incidence for equal readings while tied down and running at full throttle.

None of the differential schemes work unless the tail surfaces are centered in the propeller slipstream.

 

[JimLogan]

First of all I give my condolences to the family of the man that was killed. And now secondly I would like to know Chuck if the reason you didn't use your infamous term "smoking black hole" was because this was not an RAF aircraft that crashed?

-Jim

 

[C. Beaty]

OK, Jim. Just to make you feel better; this Magni bored a smoking black hole.

 

[Doug Riley]

Physics doesn't know from brand names.

 

[scandtours]

A Magni crashed a couple years ago, apparently as a result of a failed attempt at a low-altitude loop.

Are people perhaps starting to treat these machines as aerobatic aircraft?

Doug,
I believe you are right. Thats what come to my mind too.
As pilots become more proficient some of them (us) tend to show off by making sharp pullups in front of spectators. If carried too far, however, it may be dangerous and depending on the plane and the skill of the pilot, may or may not recover before crashing to the ground. The gyro appears to have a somewhat similar behavior with a FW and this is why many eyewitnesses of accidents described it as a falling stone or hammer stall. The big difference is of course that the rotor does not stall and the mechanism of the potential disaster is quite different. The crash is quite avoidable all the way up to the point when the gyro comes to a complete stop in the mid air.
A PULLUP-PUSHOVER does bother all kind of gyros, stable or unstable.
Giorgos

 

[Doug Riley]

Yes, Giogios, although if the airframe is stable (in all axes) there is only one danger: loss of RRPM. If the frame is not stable in all axes, there are potentially three dangers: Loss of RRPM, PPO and torque-over.

The difference is not just academic. An autogyro rotor can withstand a certain amount of RRPM loss (say, 15%) and not self-destruct. A low-G event that is too brief to cause catastrophic RRPM loss CAN nevertheless be long enough to trigger a PPO or torque-over in some machines.

If you must do a pullup in front of a crowd, do as Ken Brock always did: roll into a bank as your airspeed drops to normal. This will prevent the rotor from experiencing zero angle of attack and unloading.

A gyro designed for aerobatics would be different in several ways from a Magni or other typical sport gyro, starting with the rotor suspension.

 

[JimLogan]

Physics doesn't know from brand names.

Doug you missed my point, my aim was to chastise Mr. Beaty for his crude remarks even about people who have just passed. I recall when Farrington had died the poor man was still warm in his grave and Chuck jumped all over the guy saying this and that about him being a bad pilot.

 

[EI-GYRO]

Thread hijack alert!!!!!!!

This thread is about an accident, its causes, and its lessons.

Please dont turn it into a generalised bitching session.

The relevant issues are stability and airshow behaviour.

Someone was good enough to update us on the investigation,
let's be good enough to digest, absorb and discuss.

Anyone who's having a pissy day can vent their spleen on the
long-running ' RAF closes the doors' thread.

Big smileys all round

 

[jos]

Gyroplanes cannot fly vertical.

JOS

 

[Learjet]

As a Magni owner my condolences to the pilots' family and friends.

Reading through the reports posted and looking at the pic I'm intrigued to see that the prop (Airplast carbon fibre?) still looks perfectly intact with no damage whatoever to the tips. To me it certainly looks like the prop was not spinning when it hit the ground? I'm also amazed to see that the integrity of the structure remains so intact after reading the reports of it "falling like a stone". I don't know guys, but the pieces just aren't fitting together as snugly as I'd like - especially when considering possibilities like pushovers etc.

I'm also puzzled that if there was such severe rotor-flap so as to cause the rotor to strike the wheel spat / tyre (as per Greeny's post) why did the rotor not strike the prop and or rudder & stab as well???? Look at the schematics below and you'll see why I'm questioning this. Also both wheel spats appear to be present (still attached!) in the pic - just the tyre is missing which contradicts the report as conveyed to Greeny by his German friend. My money is on the rotor only striking the tyre on impact and not in the air!

Lastly, being involved with search and rescue for more than 15 years my experience with eye-witness accounts is that they are invariably very "hit and miss" affairs. This includes various aircraft accidents - one of which required a search area more than a kilometre long to search for a downed heli off the coast. This despite witness reports from numerous people including two other helicopter pilots and crews! The bottom line is that accidents occur literally in seconds and are also highly traumatic events to witness. Not always the makings of a clean, clinical and objective account!

Hopefully there is video footage and other post-mortem or structural evidence available which may better assist the German authorities to conclusively ascertain what the cause of the accident was, as the preliminary (albeit "hearsay") reports seem to me to be a little wide off the mark.

I'm not being defensive of the Magni here - believe me, as a Magni owner I wan't to know the details down to the last brass tack that could have caused that M14 to crash, but the overall intactness of the airframe and the lack of damage to the prop suggests to me some sort of engine out and a descent that was to some degree at least, not entirely at the mercy of gravity.

 

[Learjet]

From www.gyro-copter.de (German gyro forum)

I see this accident actually occured some 2 years ago. Was anyone able to obtain details of the actual investigation report conducted by the German aviation authority (as opposed to the Ulm public prosecutor) - assuming a proper aviation authority accident investigation was conducted?



Ermittlungen abgeschlossen. Tod des Tragschrauberpiloten beim Flugplatzfest in Blaubeuren–Sonderbuch am 04.09.2005 beruht nicht auf Fremdverschulden.

Die Staatsanwaltschaft Ulm hat ihre Ermittlungen zu dem Absturz des Tragschraubers Typ M 14 Scout 2000, der während einer Flugvorführung im Rahmen des Flugplatzfestes am 04.09.2005 in Blaubeuren-Sonderbuch aus einer Flughöhe von etwa 100 Metern abstürzte, abgeschlossen. Die Ermittlungen ergaben, dass der Absturz des Ultraleicht-Tragschraubers während einer genehmigten Flugveranstaltung auf dem Sonderlandeplatz Blaubeuren-Sonderbuch ausschließlich auf einen Fehler des Piloten zurückzuführen ist.

Tragschrauber, auch Gyrocopter oder Windmühlenflugzeug genannt, sind ultraleichte Luftfahrzeuge, die nach Erreichen einer bestimmten Rotordrehzahl ausschließlich von einer Tragschraube (Rotor) in der Luft gehalten und bewegt werden. Der Rotor wird dann nur noch vom anströmenden Fahrtwind in Bewegung versetzt. Dieser Betriebszustand wird als "Autorotation" bezeichnet. Der frei im Luftstrom umlaufende Rotor ersetzt zugleich einen festen Tragflügel. Der Rotor hat überdies den Vorteil, dass er das Fluggerät auch bei geringer Fluggeschwindigkeit in Folge der Eigendrehung in der Luft hält.

Nach den Feststellungen des Sachverständigen verlor der Tragschrauber bei einem Kurvenflug stark an Fluggeschwindigkeit, der Rotor wurde stark entlastet, rotierte langsamer und konnte keinen genügenden Auftrieb mehr erzeugen. Der Tragschrauber kippte deshalb zunächst nach vorne ab, die Rotorblätter von einer Gesamtlänge von 8,23 Meter, die im normalen Flug aussteifen, bogen sich bei nur noch sehr geringer Autorotation stark durch. Es kam zu Abschervorgängen an Elementen des Steuerungssystems und das Fluggerät kippte nach links. Dadurch wiederum bog sich das rücklaufende Rotorblatt stark nach unten, zerschlug die Radverkleidung und streifte den Reifen, wobei das Rotorblatt zerbrach. Es verschoben sich weitere Teile des Steuerungssystems und der Rotor kam schließlich ganz zum Stillstand. Das Fluggerät, das nun keinerlei Auftrieb mehr hatte, stürzte beinahe senkrecht zu Boden, zerschellte und geriet vor den Augen der zahlreichen Zuschauer in Brand. Der Pilot, ein erfahrener Fluglehrer aus der Schweiz, erlitt schwerste, tödliche Verletzungen.

Da dem Unfall kein Fremdverschulden zugrunde lag, hat die Staatsanwaltschaft Ulm nun das Todesermittlungsverfahren eingestellt.





and Googles translation: hwell:





Determinations finally. Death of the autogyro pilot with the airfield celebration in Blaubeuren Sonderbuch to 04.09.2005 is not based on foreign being to blame for.

The public prosecutor's office Ulm locked its determinations to the crash of the autogyro type M 14 Scout 2000, which fell during a flight demonstration in the context of the airfield celebration to 04.09.2005 in Blaubeuren Sonderbuch from a flight altitude of approximately 100 meters. The determinations resulted in that the crash of the ultralight autogyro is to be attributed during an authorized flight meeting on the special landing area Blaubeuren Sonderbuch exclusive to an error of the pilot.

Autogyros, also Gyrocopter or windmill airplane mentioned, are ultralight aircraft, which are kept exclusive and moved after reaching a certain rotor speed by a carrying screw (rotor) in air. The rotor is then only shifted by the flowing against wind in motion. This operating condition is called “autorotation”. The rotor freely rotating in the air flow replaces at the same time a firm wing. The rotor has besides the advantage that it holds the aircraft also with small airspeed in consequence of the self-turn in air.

After the statements of the expert the autogyro lost rotated with a turning flight strongly at airspeed, which became rotor strongly relieved, more slowly and could no sufficient lift more produce. The autogyro tipped therefore first forward, the rotor blades of an overall length of 8.23 meters, in the normal flight the out-rigid, bends with only very small autorotation strongly. Came to cutting procedures at elements of the control system and the aircraft tilted to the left. Thus again the backward-moving rotor blade bent itself strongly downward, smashed the wheel lining and touched the tire, whereby the rotor blade broke. Further parts of the control system and the rotor shifted were stopped finally completely. The aircraft, which had now no lift more, fell almost perpendicularly to soil, smashed and turned out before the eyes of the numerous spectators in fire. The pilot, an experienced flight instructor from Switzerland, suffered heaviest, fatal injuries.

Since no foreign being to blame for was the basis for the accident, the public prosecutor's office Ulm stopped now the death preliminary investigation.

 

[Vance]

That certainly clears things up.

Thank you, Vance

 

[Timchick]

It sounds almost like the same scenario as the Peasant Frog RAF crash.

 

[C. Beaty]

Hyperbole Vance? I’m shocked.

 

[EI-GYRO]

Most of the worst flying I've seen, gyro,fixed-wing and heli, has been at
fly-ins.
You dont have to pull fancy tricks in a gyro to impress folks.
The non-aviation spectators are astonished that it flies at all.
The heli-guys wet themselves if you do a power-off landing.
The fixed-wingers lose it if you do an angled or short approach.
A spot landing gets them all.

Who needs aeros?

I think fly-ins bring out the worst in many pilots.

The Peasant Frog, and this Magni are good examples.

 

[birdy]

A high thrust line machine, wide open throttle and very low airspeed combine to produce torqueover/buntover during instances of diminished rotor thrust.
Yup.
But it wouldnt matter wot configuration machine it was......... with the pilot it had.
Im not sinkn the boot into the dead bloke ere, just stateing facts, it was pilot error. No machine is imune to humanisums.

I'm intrigued to see that the prop (Airplast carbon fibre?) still looks perfectly intact with no damage whatoever to the tips.
Learjet, the rotax 4banger has a stress clutch in the redrive that prevents the usual damage if the prop suddenly stops. I know, iv suddenly stopped my WDs a few times now, and never broke one blade.
I'm also puzzled that if there was such severe rotor-flap so as to cause the rotor to strike the wheel spat / tyre (as per Greeny's post) why did the rotor not strike the prop and or rudder & stab as well????
in the event of sevier blade flap, the left main would be the one hit by the blades, and i cant see it clear enuf in the pic to say if its rthere or not.
During such a flaping event, the blades will be at their lowest point on the left side of the machine, so thats where it will strike first.
But in a PPO, their lowest point is at the back of the machine, thats why rudders and tail booms go first in PPOs.

 

[C. Beaty]

I don’t know which way the prop on a Rotax 912 turns but if CCW viewed from the rear, torque would roll the left wheel into the rotor.

However, by the time the wheel contacts the rotor, things have already gone well past the point of no return.

An unloaded rotor can only flap from precession stall. Unloaded rotors at low rpm don’t otherwise flap.

 

[birdy]

yup, 912s spin ccw.[ torque rolls the machine left side high]
An unloaded rotor can only flap from precession stall. Unloaded rotors at low rpm don’t otherwise flap.
Not always.
If the machine fell [ after AS was lost], the new virtical AS would excessivly flap the blades if the machine was pointed into the airflow, either forwards or ass first.
Alot of RRPM is lost by the time the machine starts to fall.
If it falls in the upright position [horisontal keel] and with no horisontal AS,there'd be a better than even chance of them regaining rpm. But if the machine falls nose first or ass first, with the low RRPM and still no weight on the disc, then the airflow will quickly outrun the rotor.
But, be'n a Magni, with its big HS, even if the power was cut, the machine would quickly wethercock into the virtical airflow, and if that wasnt enuf to chop the tail off, the sudden increase of AS would over flap the blades.
Either way, its time to kiss it.

Wen in dout, cut it out [power] and level out.
Iv never been in a situation yet where this is the rong move.

 

[C. Beaty]

A rotor generating zero lift can’t flap whether airspeed is outrunning rpm or not. You know that, Birdy.

When a rotor is being tilted (precessed), then differential lift force must be generated in order to do so and the higher the moment of inertia of the rotor, the greater the differential lift required. Low inertia rotors have an advantage in this situation, requiring less differential lift for a given tilt rate.

Reflexes developed from flying FWs are sometimes at odds with safe gyro operation. Airspeed, altitude, power is not necessarily the right rule for gyros. Rule #1 for gyros is to get off the power if approaching a critical out of control situation. Power off and descending vertically, a rotor is a pretty good parachute.

 

[MOL]

The 912, witch is carburetted by a Bing CV 54 float carburettor, will stop quite rapidly if the engine (carburettors) unload to zero or negative G's. Even just a to high attitude or bank without much positive G's is enough.
From the height this Magni fell, the engine had more than time enough to stop, hence the undamaged propeller.
Same thing happened with my friend here in Denmark. Did a vertical pull-up, and ended in same situation. Engine also stopped before impact. This from only 120' height. See another thread of mine.