Optimum thermalling speed display

On Thursday, September 27, 2012 12:17:38 PM UTC-5, wrote:
I agree with him, why the hell do you need a thermaling speed director, what happened to good-old hand flying the glider and taking pride in the results?

Herb, by that logic, why do you even have an airspeed indicator, or a vario? I've "hand-flown" my glider with the airspeed inop, and with the vario inop (fortunately, not at the same time), and yeah, I can do it, and even go XC if the conditions are good - but that is not the same as actually knowing what the optimum airspeed is for your weight and bank angle, so you can calibrate your "hand"!

My proposal is not for another pointer to stare at while thermalling, but as an indication of what airspeed you should be aiming for (which can vary considerably depending on wingloading and bank angle, as we all know). If your highly calibrated hand agrees, then you don't need to look at the damn thing. But if you have been flying dry for a while, then launch off at 11psf, and have to scratch up early in the day - it would be kinda nice to have that number somewhere so you can avoid scaring all your buddies...

I would still prefer a really good AOA indicator, and be done with the stupid airspeed indicator. Hey, maybe a whistle that sounds at Cl Max!

Kirk
66

On Sep 27, 11:30*am, "kirk.stant" wrote:
On Thursday, September 27, 2012 12:17:38 PM UTC-5, wrote:

I agree with him, why the hell do you need a thermaling speed director, what happened to good-old hand flying the glider and taking pride in the results?

Herb, by that logic, why do you even have an airspeed indicator, or a vario? I've "hand-flown" my glider with the airspeed inop, and with the vario inop (fortunately, not at the same time), and yeah, I can do it, and even go XC if the conditions are good - but that is not the same as actually knowing what the optimum airspeed is for your weight and bank angle, so you can calibrate your "hand"!

My proposal is not for another pointer to stare at while thermalling, but as an indication of what airspeed you should be aiming for (which can vary considerably depending on wingloading and bank angle, as we all know). *If your highly calibrated hand agrees, then you don't need to look at the damn thing. *But if you have been flying dry for a while, then launch off at 11psf, and have to scratch up early in the day - it would be kinda nice to have that number somewhere so you can avoid scaring all your buddies...

I would still prefer a really good AOA indicator, and be done with the stupid airspeed indicator. *Hey, maybe a whistle that sounds at Cl Max!

Kirk
66

Herb, thanks! I was trying to make two points:

1. Most pilots don't/can't thermal steep enough and can't tell what
bank they are flying even when told how to look at the panel or look
outside the glider.

2. You already have an instrument to tell you optimum speed and bank
to fly, it is the variometer. There is no magic perfect speed to fly
that you can predict ahead of time. Depending on the thermal itself,
I may fly slower or faster than optimum for some equation. All those
factors come down to one number, maximum climb rate! I adjust bank
angle, speed, flap setting, slip, etc until I get the best rate of
climb for each thermal.

Tim
TT

Am 27.09.2012 19:30, kirk.stant wrote:
On Thursday, September 27, 2012 12:17:38 PM UTC-5, wrote:
I agree with him, why the hell do you need a thermaling speed director, what happened to good-old hand flying the glider and taking pride in the results?

Herb, by that logic, why do you even have an airspeed indicator, or a vario? I've "hand-flown" my glider with the airspeed inop, and with the vario inop (fortunately, not at the same time), and yeah, I can do it, and even go XC if the conditions are good - but that is not the same as actually knowing what the optimum airspeed is for your weight and bank angle, so you can calibrate your "hand"!

My proposal is not for another pointer to stare at while thermalling, but as an indication of what airspeed you should be aiming for (which can vary considerably depending on wingloading and bank angle, as we all know). If your highly calibrated hand agrees, then you don't need to look at the damn thing. But if you have been flying dry for a while, then launch off at 11psf, and have to scratch up early in the day - it would be kinda nice to have that number somewhere so you can avoid scaring all your buddies...

I would still prefer a really good AOA indicator, and be done with the stupid airspeed indicator. Hey, maybe a whistle that sounds at Cl Max!

Kirk
66


Kirk,

look at
http://www.akaflieg-koeln.de/news/ne...-neue-version/

It is in german, but the diagrams should give you an idea how you can
use a string on the side of your canopy as a very simple but reliable
AOA indicator.
--
Peter Scholz
ASW24 JE

On Wednesday, September 26, 2012 8:11:07 PM UTC-4, John Cochrane wrote:
On Sep 25, 11:29*pm, "kirk.stant" wrote: With all the new (and some of the older - SN10 for example) vario-computers having accelerometers and settings for ballast and polars, would it be possible to compute and display the optimum thermalling speed adjusted for wingloading and bank angle (as a function of instantaneous G-loading)? Since we don't (yet) have AOA gauges (which would do a better job of indicating the correct speed to fly in a thermal), I'm curious if a simple "speed to fly" indication would work. Obviously, filtering a constantly varying G-load would have to be employed, but I'm thinking of a 2-3 knot speed band display - using the same fast-slow indicator used for cruise speed control - preferably also with a deadbeat digital readout of the optimum speed to thermal for an average of the past 3 seconds or so of turn/averaged G. Would this work? Probably only once established in a steady, smooth turn - but that would give a good starting point for the next thermal. Kirk 66 I think it would work very nicely. Quick, if you normally thermal your ASW27 empty at 44 knots in a 30 degree bank, what's the right speed for 12 gals of water ballast each side? What's the right speed for 50 degrees? Accurate speed control makes a big difference. It's been on my (rather long) punch list of requests to the clearnav team for a while, if anyone else were asking they'd probably do it. John Cochrane

I would expect, for such a device to be effective, there would need to be quite a complex set of inputs, both from sailplane data, and sensory input.
Some examples:
1- Glider performance information for all likely flap settings used in thermalling.
2- Current mass
3- Knowledge of and the ability to quantify and input a variable for how the glider responds to horizontal and vertical gusts
4- Airspeed input, gust input- via asi , 3 axis accelerometers.
5- A harder one- what is the next gust going to be?
6- Others I'm not bright enough to think of now.

THEN- all the programmers need to do is whiz up an algorithym that takes all these into account and pops out "the number".
The vario folks are just now, 20 years after "the Dave Ellis dream", beginning to master the next level of variometry.

I'm not surprised that the ClearNav guys haven't bitten on this. It would be really hard to do in a meaningful way and maddenly difficult to try to explain to us glider jocks how to use it.
UH

On Thursday, September 27, 2012 3:00:02 PM UTC-7, Peter Scholz wrote:
Am 27.09.2012 19:30, kirk.stant wrote:

On Thursday, September 27, 2012 12:17:38 PM UTC-5, wrote:

I agree with him, why the hell do you need a thermaling speed director, what happened to good-old hand flying the glider and taking pride in the results?



Herb, by that logic, why do you even have an airspeed indicator, or a vario? I've "hand-flown" my glider with the airspeed inop, and with the vario inop (fortunately, not at the same time), and yeah, I can do it, and even go XC if the conditions are good - but that is not the same as actually knowing what the optimum airspeed is for your weight and bank angle, so you can calibrate your "hand"!



My proposal is not for another pointer to stare at while thermalling, but as an indication of what airspeed you should be aiming for (which can vary considerably depending on wingloading and bank angle, as we all know). If your highly calibrated hand agrees, then you don't need to look at the damn thing. But if you have been flying dry for a while, then launch off at 11psf, and have to scratch up early in the day - it would be kinda nice to have that number somewhere so you can avoid scaring all your buddies...



I would still prefer a really good AOA indicator, and be done with the stupid airspeed indicator. Hey, maybe a whistle that sounds at Cl Max!



Kirk

66





Kirk,



look at

http://www.akaflieg-koeln.de/news/ne...-neue-version/



It is in german, but the diagrams should give you an idea how you can

use a string on the side of your canopy as a very simple but reliable

AOA indicator.

--

Peter Scholz

ASW24 JE

More strings on canopies = windfall for Bumper. Well done ;-)

I probably thermal too slowly and with too much bank. Lately it seems every time I try to open up the turn even a little I blow out the edge of the thermal.
Having an instrument to yell at me might improve my thermalling, or really **** me off!

On Tuesday, September 25, 2012 9:29:44 PM UTC-7, kirk.stant wrote:
With all the new (and some of the older - SN10 for example) vario-computers having accelerometers and settings for ballast and polars, would it be possible to compute and display the optimum thermalling speed adjusted for wingloading and bank angle (as a function of instantaneous G-loading)? Since we don't (yet) have AOA gauges (which would do a better job of indicating the correct speed to fly in a thermal), I'm curious if a simple "speed to fly" indication would work. Obviously, filtering a constantly varying G-load would have to be employed, but I'm thinking of a 2-3 knot speed band display - using the same fast-slow indicator used for cruise speed control - preferably also with a deadbeat digital readout of the optimum speed to thermal for an average of the past 3 seconds or so of turn/averaged G. Would this work? Probably only once established in a steady, smooth turn - but that would give a good starting point for the next thermal. Kirk 66

Last year I became a syndicate partner in a lovely LS7 (without
winglets). Our panel contains an LNAV which has the optional g
meter and the climb tone changes in lift if the angle of bank is too
great and the glider approaches the stall. Best thermalling speed is
just slow enough for the tone not to change. It is even possible to
change the ballast setting on the LNAV; works for us.

I am always struck by the inability of bloggs to bank at 45 degrees.
The screws on the panel trick works and many are quite surprised
at how steep this feels. They are then even more surprised by how
much the stalling speed goes up!

Tally ho!

John

Last year I became a syndicate partner in a lovely LS7 (without
winglets). Our panel contains an LNAV which has the optional g
meter and the climb tone changes in lift if the angle of bank is too
great and the glider approaches the stall. Best thermalling speed is
just slow enough for the tone not to change. It is even possible to
change the ballast setting on the LNAV; works for us.

I am always struck by the inability of bloggs to bank at 45 degrees.
The screws on the panel trick works and many are quite surprised
at how steep this feels. They are then even more surprised by how
much the stalling speed goes up!

Tally ho!

John

Two thoughts on this:

1) There is no substitute for practice.
2) If you need a computer for everything you might as well let the computer
fly the glider. Why have the middleman?



At 10:58 28 September 2012, John Roche-Kelly wrote:
Last year I became a syndicate partner in a lovely LS7 (without
winglets). Our panel contains an LNAV which has the optional g
meter and the climb tone changes in lift if the angle of bank is too
great and the glider approaches the stall. Best thermalling speed is
just slow enough for the tone not to change. It is even possible to
change the ballast setting on the LNAV; works for us.

I am always struck by the inability of bloggs to bank at 45 degrees.
The screws on the panel trick works and many are quite surprised
at how steep this feels. They are then even more surprised by how
much the stalling speed goes up!

Tally ho!

John

On Thursday, September 27, 2012 3:50:35 PM UTC-6, Tim Taylor wrote:

1. Most pilots don't/can't thermal steep enough and can't tell what

bank they are flying even when told how to look at the panel or look

outside the glider.



2. You already have an instrument to tell you optimum speed and bank

to fly, it is the variometer. There is no magic perfect speed to fly

that you can predict ahead of time. Depending on the thermal itself,

I may fly slower or faster than optimum for some equation. All those

factors come down to one number, maximum climb rate! I adjust bank

angle, speed, flap setting, slip, etc until I get the best rate of

climb for each thermal.

Tim, I totally agree about bank angle - steep is good! And I mostly agree on your second point, about varying a bunch of parameters to find what works best in any particular thermal. Where I disagree, probably due to less experience, is that there isn't room for better instumentation to tell the pilot what exactly his glider is doing. Min sink is min sink - it only happens at one angle of attack. That equates to one unique airspeed for every combination of bank angle and wing loading. Think of it as Mcready speed - a wonderful invention, gives the theoretical optimum cruise speed to fly, made cross country faster, etc.. and all our fancy computers give us a variety of indicators on how fast to fly, when to push or pull, audio tones, etc.. Of course, a lot of us just use it as a guide and adjust our speed for the conditions at hand, since the bloody black box isn't looking out the window!

I'm just thinking that the equivalent for thermalling might be useful.

Cheers,

Kirk
66