[Rick Masters]

Wow. Can anybody keep up with Harry?

[Harry]

One more question Rick. Did the BEEP/BOOP change frequency with strength of temperature difference? Right now, my circuit just indicates a difference. Would an indication of how strong the rate of change is be of benefit?

[Bill Cummings]

Hi Harry,
Mine will speed up in beeps/boops if the temperature is changing quickly.

[Harry]

Hi Harry,
Mine will speed up in beeps/boops if the temperature is changing quickly.

Bill, thanks, that helps a lot. I can build that feature into my design as well. I still have a a couple more months to kill before the snow melts away and the flying season picks up for me. I may try adding selectable features so I can play with sensitivity, gain, audio, etc. while I fly.

I really like the idea of using it to gauge the thermals as they roll up the hill.

[Rick Masters]

What its's like to fly with a Thermal Snooper

[Rick Masters]

Would an indication of how strong the rate of change is be of benefit?

It could indicate the probability of strong turbulence.
A strong rate of change could trigger an audio recording of "Pull in, you fool."

[Harry]

What its's like to fly with a Thermal Snooper

After watching these clips, I'm now even more curious about installing wingtip sensors.
My sensor design is sensitive enough to warrant a try.

I envision using my TS the way Rick used his. Then with additional sensors at each wingtip, they could be used to indicate thermal activity to the left or right. Won't cost me much more to try.
I have no idea if they will help or not. It's just a curiosity and would make for an interesting summer experiment.

[Rick Masters]

I'm not knocking it. I'd like to know the results.
But I could have done that in 1986-87 - I had lots of Snoopers - but I didn't go to the trouble.
I figured it would just tell me, most of the time, which side of a tumbling parcel of air shed from a thermal is warmest.


So here we go.
I'm flying with a single sensor. You're flying with wingtip sensors.
Harry, make sure your wingtip sensors are well-shaded. Maybe under the wingtips.
Otherwise Mr. Sun will heat one up more than the other during your turns and play a trick on you.
For me, with a single sensor and no pesky differential to interpret, not such a large impact.
(Watch the video for sunlight striking the Snooper on turns. Can you detect a difference? I can't.)
But if you use wingtip sensors and look for a differential, watch out for Mr. Sun!
He's a trickster.

So you've got that thorny little problem solved and there we are, flying along side by side.
Suddenly our Snoopers go off, all three of them.
But one of the two on your 10-meter span Fledge is beeping faster.
You think, "Ah, ha. I must turn left!"
And you do.
Me, my Snooper is chirping excitedly. I wait. It falls off, then picks up again.
I think, "Ah, ha. There must be a thermal nearby. I must turn and start a search pattern!"
So I turn right. I turn right because you are off to my left and I don't want to fly too close to you.
Meanwhile, your vario beeps -- "A thermal must be there!" you cry-- and you crank and bank.
You go up. You go down. But at the end of your turn, you haven't gained anything.
"What happened?" you ask. "It must have been one of those imaginary parcels of swirling air Rick keeps ranting about!"


So I continue on my search pattern off to the right. The Snooper quiets down. So does the vario.
"Must not be over here," I think.
As I straighten out from my first 270-degree turn, I see you floundering around in a tumbling parcel of air, eyes locked madly on a clever, fluttering arrow amid the blinking lights of your prototype instrument panel. (I feel a cartoon coming on...)
Now I fly straight, on past you. My Snooper begins chirping excitedly. I continue to fly straight.
"I know you're over here!" I yell to the invisible thermal. The Snooper is excited.
Suddenly my sail shudders and my left wingtip lifts. That could be it! The Snooper has quieted down but the vario is chirping.
THAT'S THE SIGN!!!
Warm air - all around me! Not changing temperature! I crank and bank. The Snooper has fallen mostly silent while the vario screams. I am in the core.
You drop away like a bug.

Now let's look at separation distances.
The separation distance between your wingtip sensors is 10 meters. Always.
That's the distance you intend to use to generate a differential.
Not enough. Its only 5 meters from the central point. Not enough.
And you will agree that my single Snooper is always providing the midpoint of your differential from its central location - so are you achieving anything measurable with two sensors so closely spaced?
But if I take a sample, then count one second while flying at 25 mph and then take another, I too have about 10 meters of separation.
Our separations are the same, but perpendicularly oriented along the horizontal plane.
Now we must face a preconception.
If you are searching for something but do not know where it is, so what is the difference between guessing it is straight ahead or off to the side?
Answer: none. A guess is only a guess.
You go first. I follow.
With wingtip Snoopers, you think a differential between your Snoopers will provide you with information to indicate which way to turn.
I just think I'll turn after the Snooper makes noise during the time it takes me to fly the distance of the wingspan of a 747.
Your wingspan is 10 meters perpendicular to your flight path.
Mine is 60 meters (or any length I wish) along my flight path. Vastly superior.
Although I use only one thermistor, my sample is larger.
Now, with a single Snooper, I take a guess as to where a thermal might be and fly in that direction. The Snooper provides no guidance at all.
I contend 10 meters is insufficient in the macro environment of thermals, so I instead count two seconds.
Now I have 20 meters. Still insufficient.
You know what I like? I like the wingspan of a 747. That's over 60 meters, or about 6 seconds of flying straight and listening for the Snooper to pick up and stay excited. With that distance, I can pass through several parcels of swirling air and decide to initiate a search pattern when the BEEP/BOOPS start falling off.
Okay, I admit you can do this too with two (or ten or fifty) sensors.
I simply contend you will gain nothing by adding a second sensor because a Snooper is not a thermometer.
It is a device that indicates thermal turbulence, suggesting that a thermal is close by.
It is not a thermometer. It is not directional.
But go ahead, prove me wrong.
(I can hear the cheers from the peanut gallery...)

-----------
My daily dose of Mr. Sun. Highly recommended.
http://www.suspicious0bservers.org

[Harry]

Rick,

No problem. Note, I do not have a Thermal Snoop I or II. This is a whole different animal and just an experiment. I'm not trying to prove anything. I just plan on collecting data. I'll share the results when done.

[danstrider]

It's neat to see so much revived interest in the ideas of the snooper other than me. Cool that you're making progress Harry! Beating me for sure. You'll definitely be first to find the magic.

Everyone I talk with about the circuit has promoted updating the amplifier using parts other than a series of inverters. In all discussions, we've come back to the idea that the tuning of the filters based on flight testing is likely where the magic lies. Whether it's an instrumentation opamp or Alan's creative usage of inverters is an implementation decision. That being said, I'm working toward copying the original snooper as closely as possible and hope to compare its output to the original. That way there is at least confirmation the original can be duplicated and measured. Folks like you Harry are pushing into new and fun territory.

Rich, reading all your posts made me curious about the length of time of beeps and boops. Specifically, you often talk about the snooper being active as the clue that you're approaching a thermal, then the vario beginning to chirp as the snooper goes quiet as an indication of the core. Out inbetween thermals, is the snooper relatively quiet, then gets noisy for some number of seconds, then gets quiet as you begin to core? If so, the effort you put into tuning withstanding, is it the activity of the snooper noise that is your real clue? You have warned about adding more sensitivity and ruining the tuning. Do you think that more sensitivity would make the snooper much more noisy all the time, thereby removing the ability to hear when a difference between noisy and quiet? If this is the case, this provides a clue about the magic.

Dan