What could possibly go wrong?

[PJB]

I recently recieved an email from AutoGyro that contained this link:-

AutoGyro chat

I focused upon the GyroMotion and looking at the picture of the Calidus driving around the highway and wonder just what work has been done to consider the stresses on those rotor blades and how it might affect their life...

 

[Brent Drake]

I can see rotor-bearing failure in the future. due to vibration and chuckholes.

 

[Andino]

Thank you, Phil, good point. In my opinion, the more dainty the rotor system, and the rougher the ground, the more religiously it should be taxied with some prerotation. AutoGyro is one of the last companies I'd look to for proper examples about gyroplanes. I find their engineering and their habits to be flippant, but with strong marketing and scaled up production they've generally so far gotten away with their flippancy.

 

[PJB]

What will be interesting is how [if any] further airworthiness will be required or if you just buy some electric motors for the wheels, deal with the automotive licensing and crack on. If its the later I expect to see these things falling out of the sky with some frequency given the additional stress all that rotor flex / flap from driving on the road - in fact given the state of most UK roads it may even fail on the road journey!

 

[Andino]

What will be interesting is how [if any] further airworthiness will be required or if you just buy some electric motors for the wheels, deal with the automotive licensing and crack on. If its the later I expect to see these things falling out of the sky with some frequency given the additional stress all that rotor flex / flap from driving on the road - in fact given the state of most UK roads it may even fail on the road journey!

To be sure. In typical AG fashion, any overstressed rotor system failures will be blamed on "extreme operations not authorized in the manual." That allegation was used when their original set of rotors began cracking.

 

[Aerofoam]

At least they have a cable supporting the blades from the top and are on a very nice road.
There is no way that would work for extended travel....
If you did that in Tucson, you would have to go back to get your wheels out of pot holes..

 

[Andino]

why should they know their fate,
Since sorrow never comes too late,
And happiness too swiftly flies?
Thought would destroy their paradise.
. . . where ignorance is bliss,
'Tis folly to be wise.

 

[PJB]

At least they have a cable supporting the blades from the top and are on a very nice road.
There is no way that would work for extended travel....
If you did that in Tucson, you would have to go back to get your wheels out of pot holes..

Sounds like Tucson and British roads are similar!

 

[Tyger]

I promise you the roads are a lot WIDER in Tuscon. So, likely more potholes per linear foot.

 

[loftus]

Possibly a little premature to condemn here just on this photo. Lots of photos out there of gyros taxiing to gas stations etc. Not sure why a road like in the picture is any better or worse than taxiing on any runway or taxiway. We've of course seen the videos of gyros driving around streets, again with the blade secured and good roads, no different to taxiing in the airport.

 

[PJB]

Possibly a little premature to condemn here just on this photo. Lots of photos out there of gyros taxiing to gas stations etc. Not sure why a road like in the picture is any better or worse than taxiing on any runway or taxiway. We've of course seen the videos of gyros driving around streets, again with the blade secured and good roads, no different to taxiing in the airport.

Hey - not necessarily a condemnation more a question mark around what has or has not been considered because not only do we have [arguably] one of the worlds leading aeronautical universities [Cranfield] give a view on the contributory factors to AutoGyro blade cracking but we also have a several fatal AutoGyro accidents where blades may have failed along with air worthiness bulletins revising things that were apparently valid, but are not anymore.

What I am 100% sure of is that driving around the highway is not like taxiing in the airport. Even if we lived in the most well paved areas and choose to drive as slowly as we might when taxiing the increased distances / time spent in this phase surely needs to be accounted for.

Had the propulsion for the "driving" phase been done with the motor running /turned on you might well be able to make a case that the extra time is accounted for because the hobbs meter may well suffice, but the propulsion on the ground is via electric motor and independent of the flying elements.

Perhaps its all be considered and this is all nonsense but actually knowing the company and its focus I might like to see the POH/information that is highlighted to purchasers and what process is to be followed as this will stress the rotors much more.

 

[Resasi]

Remember an ASRA Forum discussion about taxiing, and whether having a rotor turning and partially supporting itself with generated lift was better than taxiing with it parked, when runway conditions/smoothness were likely to generate concerns about adverse stress of hub/bearings/blade roots.

Without the specific knowledge to back it up, my personal opinion was having the rotor turning was the better option.

 

[WaspAir]

The McC J-2 manual strongly advises it.

 

[Doug Riley]

It would be interesting to find out if the earlier Cierva models, which had flap hinges, kingpost with landing wires, and steel (not aluminum) spars, fared better in terms of fatigue from taxiing with blades stopped. The rotor head bearings still take a pounding, though.

As a grass-strip gyronaut, I always prespin my blades to whatever RRPM they'll achieve at engine-idle (or as fast as possible armstrong-style, if no prerotator). It's almost physically painful to watch them bowing and flexing if you taxi on grass with them stopped. I don't even like to do it on asphalt.

 

[gyrojockey]

For me it's about "best practice & safety" So I have to agree with @Philbennett - flexing those blades like double d's on baywatch could be detrimental later on in their life span. I don't even like the blades hanging down on their own while parked in the hanger!

The flex point / weak spot of the blade is right at the end of the hub bar, stressing the blade beyond its elasticity at that point could lead to premature failure, just like bending a piece if wire continuously till it breaks.

I don't want to test out the theory on my way down from 2000ft to my untimely death & cremation.

 

[Burrengyro]

What is the life expectancy of Magni rotor blades with low hours but 10 plus years in age? How does one compare an older Magni M16 (say 12 years) with low engine hours to a younger Magni with the same engine hours but only say 3 years old?

 

[PJB]

I don't know the answer to the life question but did you see the May edition of the LAA magazine ref the corrosion?

 

[PJB]

flexing those blades like double d's on baywatch

nice! Although these days DD's are small!

 

[Burrengyro]

I don't know the answer to the life question but did you see the May edition of the LAA magazine ref the corrosion?

Hi Phil, I did come across an interesting CAA produced document on corrosion: Corrosion and Inspection of General Aviation Aircraft CAP 1570, which makes an interesting read. I didn't see the LAA reference to corrosion. Any warnings we should know about concerning Magni, ELA of Autogyro products?

 

[Brian P]

I don't know the answer to the life question but did you see the May edition of the LAA magazine ref the corrosion?

Frightening on many levels.