Adverse yaw on Viscount...

[Viscount Cornbank]

Have to have a look at that, I must confess I always use the balance ball/slip pointer but don't pay much attention to the turn pointer. Will check it the next time I'm up

cheers

Fraser

[DaveB]

This is what happens when you answer a question without thinking about it I realised as soon as Macs pointed that out that it was so much codswallop but in my defence.. I've scoured the internet and come up with absolutely zero for info on that type of indicator. Everyone, everywhere will explain how modern systems work (including the explanation above) but zilch for older instruments :roll:

There are variations of the Viscount T&S (older I might add) that calibrate 1, 2, 3 and 4 either side of centre but I simply can't find enough info on them :brick:

ATB

DaveB :tab:

[Macs]

This is what happens when you answer a question without thinking about it I realised as soon as Macs pointed that out that it was so much codswallop but in my defence.. I've scoured the internet and come up with absolutely zero for info on that type of indicator. Everyone, everywhere will explain how modern systems work (including the explanation above) but zilch for older instruments :roll:

There are variations of the Viscount T&S (older I might add) that calibrate 1, 2, 3 and 4 either side of centre but I simply can't find enough info on them :brick:

ATB

DaveB :tab:

Dave, David,
Now that I think about it, I really have not paid attention to the TURN gauge, to see if it actually moves (gives any indications). I'll take a look at it later today, as if it does not, all this is a moot point...

regards,
Macs

[DaveB]

Macs..

I spend a great deal of my VA time sitting in front of one of these T&S cooridinators (in the Vanguard) and it dawned on me that we have our very own Vanguard pilot here on the forum.. none other than Peter McLelland Here's Peter's explanation so that this can be put to sleep and we can all rest easy in our beds

The turn needle indicates over a scale of Rate One, Rate Two, Rate Three and Rate Four...Rate One is 3 degrees per second or two minutes for a 360 degree turn. So far absolutely fact...From now on assumptions...Rate Two might be 6 degrees per second or one minute for a 360 degree turn...Rate Three might be 9 degrees per second or 40 seconds for a 360 degree turn...And Rate Four a proper steep turn could be 12 degrees per second or 30 seconds for a 360 degree turn. I'm reasonable confident that these last three are correct.

It seems so obvious when you see it like that doesn't it VMT to Peter ;-)

ATB

DaveB :tab:

[DaveB]

Hello Mate..

On the surface, I'd be inclined to agree with you. As far as I'm aware.. the Vanguard was the last civvie aircraft to have this type of Turn Coordinator fitted (Vickers that is) which, it has to be said, was a throwback from another era. Perhaps it was building on a known design leaving much of the instument 'not available for use'. Certainly, it changed on the VC10 and by the time they built the 1-11.. the now standard gauge was fitted (standard turn needle on the top with ball on the bottom). You see almost exactly the same gauge in the front of a Mossie though I guess the Mossie was far more capable of reaching the instruments limit

ATB

DaveB :tab:

[MALTBY D]

It's an interesting one this.
Looking at Fraser's code, it is set to indicate '4' when at 12 degrees per second, which matches what Peter had said.
I notice that is also the same as the default Comet Racer's gauge, which is also marked with TURN 1,2,3,4 in a similar way.

So, I'd guess Fraser's gauge is indeed working correctly.
As DB says maybe the Viscount/Vanguard did have a generic unit that they just put in everything, even though most of the range is useless.
I tried & could only just get over a reading of 2 in the Viscount model & obviously that was with no worries that the wings would come off!
I can't, at the moment, think why anyone would want to attempt to judge a rate 4 turn using this kind of instrument, even in a Mossie. :o

The later version of the Turn gauge on the VC10 & 1-11 does have a max reading of Standard Rate 1 (3 deg per sec), with markings at half & quarter.
There are no numbers on those instruments though.

DM

[DaveB]

I looked at the gauge on the Vanguard this afternoon while on a quick little earner to Brussels and concur very much with that DM. I find this sort of thing with APEP at Brooklands all the time. The theory from our team of aged desparados is that Vickers bought bulk orders of everything which, it has to be said helps us get spares from the most unlikely sources A short while ago, one of our LP fuel MI's went bonkers and Fraser sent one he had which he thinks might have come off a Victor. It works a treat too A little while later, Fraser spotted an undercarriage indicator on ebay for a Hunter so I bid for and got it. Fit's EP a treat (although it has to be said the outer casing is not of the same type) ;-)

ATB

DaveB :tab:

[Macs]

I looked at the gauge on the Vanguard this afternoon while on a quick little earner to Brussels and concur very much with that DM. I find this sort of thing with APEP at Brooklands all the time. The theory from our team of aged desparados is that Vickers bought bulk orders of everything which, it has to be said helps us get spares from the most unlikely sources A short while ago, one of our LP fuel MI's went bonkers and Fraser sent one he had which he thinks might have come off a Victor. It works a treat too A little while later, Fraser spotted an undercarriage indicator on ebay for a Hunter so I bid for and got it. Fit's EP a treat (although it has to be said the outer casing is not of the same type) ;-)

ATB

DaveB :tab:

This indeed has been a very interesting post. I would like to add another possible theory for fitting this type of gauge on an airplane like the Viscount: Maybe they had a bunch of spare ones, and thus made them economically attractive (they do what they are supposed to also, so no safety concern there). Maybe that is why I have not seen it move much even with relatively steep bank angles! Like Dave pointed out. Thanks to all for your input, surely have enjoyed it.
regards,
Macs

[DaveB]

Of course, none of this has anything to do with "adverse yaw"

Ah.. you noticed

Have a nice break mate.. hope the wx holds ;-)

ATB

DaveB :tab:

[Macs]

Of course, none of this has anything to do with "adverse yaw" (yaw in the opposite direction to roll) which can be caused by several things... but I am about to go rock climbing with the kids ... so maybe later

The original question had two parts; the last part of the question got most of the attention. DaveB quickly answered the first part relating to handling of the aircraft(relating to adverse yaw). Have a good one camping. Again, thanks to everybody for your input
regards,
Macs