JimmyMac
Lifetime Supporter
Memorial Day Air Show from Jones Beach , NY
My mate up in Montana sent me these.
My mate up in Montana sent me these.
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For the Airmen
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Paul Thompson 'Hooligan'
Admin
Cool pics James - :thumbsup:
One thing surprised me though, on pic 7, the Blue Angel F18s with 'Fat Albert' C130 - the 4 props are almost exactly in positional sync with each other. (yeah I know, the strangest details interest me)
Anyone know if this is common? is there a reason for it? - or is it just per chance?
Anyone........
One thing surprised me though, on pic 7, the Blue Angel F18s with 'Fat Albert' C130 - the 4 props are almost exactly in positional sync with each other. (yeah I know, the strangest details interest me)
Anyone know if this is common? is there a reason for it? - or is it just per chance?
Anyone........
Pete McCluskey.
Lifetime Supporter
Yes I noticed that also, pure chance or dare I say it, a Photoshop of a stationary aircraft put into the formation?
Cool photos either way. Thanks for posting Jimmy.
Cool photos either way. Thanks for posting Jimmy.
David Morton
Lifetime Supporter
It was the engineers job to sync the props - especially on the Shackleton where there were 8 turning. If he proved incapable a tin of beans would bounce of the back of his hard hat until he got it sorted. This sort of picture is the result of good synchronisation - which anyway is done automatically these days. The engineers role has been replaced with a processor which is not flatulent and doesn't crack bad jokes.
Paul Thompson 'Hooligan'
Admin
Hi David -
I guess the more synchronised they are, the less droning/beating you get so it's easier on the ears.. are there any other benefits? (other than the flight engineer's reputation and skull :laugh
Also, synchronising motor speed I can understand but do they actually sync prop position too? (i.e - between engines)
I guess the more synchronised they are, the less droning/beating you get so it's easier on the ears.. are there any other benefits? (other than the flight engineer's reputation and skull :laugh
Also, synchronising motor speed I can understand but do they actually sync prop position too? (i.e - between engines)
Pete McCluskey.
Lifetime Supporter
Hi David, I've always thought the Pilots synchronised the engines using the throttles. I didn't know the Engineers also did it. Excuse my lack of knowledge I have never flown multi engined aircraft.
David Morton
Lifetime Supporter
Not by using the power levers Pete, but the prop levers especially on turbines (ie PT6 Allisons etc ). The cockpit indication is a small display of usually 3 (sometimes 4) rotors for a 4 engine aeroplane and its then easy to synch the other 3 when the 3 small rotors stop turning. (It's a good indication of which one has failed during a check ride....)
Paul - yes it can often happen that way when all 4 are in perfect synch - something the engineers seldom did. Benefits are a massive reduction in vibration
which should be helpful on aeroplane fatigue and riveted structure, of which the Shackleton was one (described as 40,000 loose rivets in formation).
Even RB211's on the 757, 767, and 747 on high mileage machines can benefit in the cruise from a slight tweaking to stop though FADEC seems to have it sorted on the later machines. If I ever sit down in third world (rarely) on the older machines I hear it all the time though I guess the Nigel and Baldrick with their noise reducing headsets in the pointy end are not trained to hear it any more. But I've found the answer - I've bought a decent noise reducing (ANR) headset as well though you can still feel the problem through the seat of your pants.
Paul - yes it can often happen that way when all 4 are in perfect synch - something the engineers seldom did. Benefits are a massive reduction in vibration
which should be helpful on aeroplane fatigue and riveted structure, of which the Shackleton was one (described as 40,000 loose rivets in formation).
Even RB211's on the 757, 767, and 747 on high mileage machines can benefit in the cruise from a slight tweaking to stop though FADEC seems to have it sorted on the later machines. If I ever sit down in third world (rarely) on the older machines I hear it all the time though I guess the Nigel and Baldrick with their noise reducing headsets in the pointy end are not trained to hear it any more. But I've found the answer - I've bought a decent noise reducing (ANR) headset as well though you can still feel the problem through the seat of your pants.
Great photos Jimmy,
When I flew as a passenger in Viscounts there were certain seats to avoid due to the significant amount of vibration due to changing synchronisation. Although it would be reasonably under control in cruise, during throttle changes and full throttle at take off in particular, you could be in for an ear And a body bashing in some of the forward seats.
Dave
When I flew as a passenger in Viscounts there were certain seats to avoid due to the significant amount of vibration due to changing synchronisation. Although it would be reasonably under control in cruise, during throttle changes and full throttle at take off in particular, you could be in for an ear And a body bashing in some of the forward seats.
Dave
