??????????

[Adrian S]

Birdy,Sounds like Retreating blade stall, definately something we all need to avoid. At Biggendon our guest speaker spoke about it within the context of the old Bensen blades and pulling high G manuevours. One thing you may find useful is the warning device they fitted to the early heads so you got advance warning of its onset. The fitting of a light spring steel tab from the teetering stops allows feedback through the stick prior to the onset of the blade stall. I will ask Pete Barsden to post a photo of what I am talking about as I wont get to my gyro for a few weeks to take a photo of what I have on one of my gyro's. If you want any more info give me a call 0427094552 or A/hrs WST 08 95612979.Regards,Adrian

[Adrian S]

Birdy,Sounds like Retreating blade stall, definately something we all need to avoid. At Biggendon our guest speaker spoke about it within the context of the old Bensen blades and pulling high G manuevours. One thing you may find useful is the warning device they fitted to the early heads so you got advance warning of its onset. The fitting of a light spring steel tab from the teetering stops allows feedback through the stick prior to the onset of the blade stall. I will ask Pete Barsden to post a photo of what I am talking about as I wont get to my gyro for a few weeks to take a photo of what I have on one of my gyro's. If you want any more info give me a call 0427094552 or A/hrs WST 08 95612979.Regards,Adrian

[birdy]

Getn confused ere.Chuck B. on the yank forum said blade stall, but its gota be a different stall to wot your refern to Adrian, coz it wouldn't matter if you had sum sorta warning devise fitted thatd warn of wot happened t me, coz itd be happening simultainiosly with the warning.IOW, the time lag between the stick input and the start of the 'noise' wouldn't be long enough to take measures to prevent the 'stalling', if that is wot happened.If there was any contact with the stoppers, it wasn't much, coz i don't remember any violent kickn from the stick.Ignorance is bliss............but only till you realise you were.birdy, here.

[birdy]

Getn confused ere.Chuck B. on the yank forum said blade stall, but its gota be a different stall to wot your refern to Adrian, coz it wouldn't matter if you had sum sorta warning devise fitted thatd warn of wot happened t me, coz itd be happening simultainiosly with the warning.IOW, the time lag between the stick input and the start of the 'noise' wouldn't be long enough to take measures to prevent the 'stalling', if that is wot happened.If there was any contact with the stoppers, it wasn't much, coz i don't remember any violent kickn from the stick.Ignorance is bliss............but only till you realise you were.birdy, here.

[birdy]

Getn confused ere.Chuck B. on the yank forum said blade stall, but its gota be a different stall to wot your refern to Adrian, coz it wouldn't matter if you had sum sorta warning devise fitted thatd warn of wot happened t me, coz itd be happening simultainiosly with the warning.IOW, the time lag between the stick input and the start of the 'noise' wouldn't be long enough to take measures to prevent the 'stalling', if that is wot happened.If there was any contact with the stoppers, it wasn't much, coz i don't remember any violent kickn from the stick.Ignorance is bliss............but only till you realise you were.birdy, here.

[birdy]

Getn confused ere.Chuck B. on the yank forum said blade stall, but its gota be a different stall to wot your refern to Adrian, coz it wouldn't matter if you had sum sorta warning devise fitted thatd warn of wot happened t me, coz itd be happening simultainiosly with the warning.IOW, the time lag between the stick input and the start of the 'noise' wouldn't be long enough to take measures to prevent the 'stalling', if that is wot happened.If there was any contact with the stoppers, it wasn't much, coz i don't remember any violent kickn from the stick.Ignorance is bliss............but only till you realise you were.birdy, here.

[Waddles]

Gidday Birdy,You indicate that when you heard the noise you had basically zero forward airspeed. This being the case, I don't think retreating blade stall was the cause, because the relative speed of both blades would have been the same. We know that in a turn such as this the blades "overcone" significantly before centrifugal force can flatten them out, so the rotational speed increase would have been significant, initially anyway. Maybe this coning caused the blade skins to "tin can"?How about sonic boom from the blade tips?Waddles.

[Waddles]

Gidday Birdy,You indicate that when you heard the noise you had basically zero forward airspeed. This being the case, I don't think retreating blade stall was the cause, because the relative speed of both blades would have been the same. We know that in a turn such as this the blades "overcone" significantly before centrifugal force can flatten them out, so the rotational speed increase would have been significant, initially anyway. Maybe this coning caused the blade skins to "tin can"?How about sonic boom from the blade tips?Waddles.

[Waddles]

Gidday Birdy,You indicate that when you heard the noise you had basically zero forward airspeed. This being the case, I don't think retreating blade stall was the cause, because the relative speed of both blades would have been the same. We know that in a turn such as this the blades "overcone" significantly before centrifugal force can flatten them out, so the rotational speed increase would have been significant, initially anyway. Maybe this coning caused the blade skins to "tin can"?How about sonic boom from the blade tips?Waddles.

[Waddles]

Gidday Birdy,You indicate that when you heard the noise you had basically zero forward airspeed. This being the case, I don't think retreating blade stall was the cause, because the relative speed of both blades would have been the same. We know that in a turn such as this the blades "overcone" significantly before centrifugal force can flatten them out, so the rotational speed increase would have been significant, initially anyway. Maybe this coning caused the blade skins to "tin can"?How about sonic boom from the blade tips?Waddles.

[Echo]

...it was probably Harry trying to kick his way out of the holster... " gett'n the f%@k outa 'ere !"

[Echo]

...it was probably Harry trying to kick his way out of the holster... " gett'n the f%@k outa 'ere !"

[Echo]

...it was probably Harry trying to kick his way out of the holster... " gett'n the f%@k outa 'ere !"

[Echo]

...it was probably Harry trying to kick his way out of the holster... " gett'n the f%@k outa 'ere !"

[asra]

I have heard similar singular whacking sounds come from metal rotors when pilots have 'horsed' them into the air before they were quite ready for fly. Even done it myself and heard it clearly. That sounds like Allan's possible explanation might cover this event too when the rotors are majorly coned taking the weight before full centrifical forces take over and spring them back to correct flying condition.PeteBairnsdale,Vic.