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Jan 02, 2012, 07:06 PM
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Andy W's Avatar
I thought it was pretty reliable at indicating lift in normal use? Sounds like it's indicating lift and sink when there isn't any..
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Jan 02, 2012, 10:26 PM
2.1.9 Forever
Miami Mike's Avatar
Quote:
Originally Posted by Andy W
Odd. Why would it not simply 'echo' the other modes?
The other modes, which are (1) rudder-wagging and (2) triggering an alarm signal in a radio with telemetry, are not as immediate and precise as you'd expect an audible tone to be; they're "Boolean", meaning that they can only indicate yes or no - you're going up or you're not. A variometer tone normally distinguishes between going up, going down, and holding altitude, and even gives you indications of relative rates of vertical speed.

My impression is that people are happy with the Boolean modes, but I'm skeptical about how well the variable tone mode works. I wonder if Winged Shadow Systems actually tested that mode with actual flights in a sailplane somehow. If not, it's beginning to look like it doesn't work as well as they assumed it would. If so, I'd like to know what sort of transmitter system they devised to listen to the tones.
Jan 03, 2012, 10:09 AM
Registered User
Quote:
Originally Posted by Miami Mike
I wonder if Winged Shadow Systems actually tested that mode with actual flights in a sailplane somehow. If not, it's beginning to look like it doesn't work as well as they assumed it would.
- Has anyone contacted Dave to discuss the problem, yet?

Quote:
Originally Posted by Miami Mike
If so, I'd like to know what sort of transmitter system they devised to listen to the tones.
- Why would the Tx system affect the tones? You are simply passing the Thermal Scout output thru so it appears the Tx/Rx function is working.




I just got my version 1 updated and plan to do the same thing with it. I need to get the Tx/Rx and associated parts next. Too cold to fly here tho.

Thanks.
Jan 03, 2012, 02:45 PM
2.1.9 Forever
Miami Mike's Avatar
Quote:
Originally Posted by JrcSeller
Why would the Tx system affect the tones?
It affects the tones by making them audible.

In other words, you can't tell how well the tones indicate your vertical speed until you've devised a way to listen to them while your glider is flying and working thermal lift. I wonder if Winged Shadow Systems actually did that.

As an aside, I also mentioned that if they actually did test the Thermal Scout's audio tone function in flight, I'd like to know what sort of transmitter-receiver combination they came up with to do that. Maybe they have a cheap and practical solution that we could use too, but the fact that they've never recommended anything suggests that they've never actually tried the tone function in a glider and are leaving it to their customers to be their lab test rats.
Jan 04, 2012, 06:00 AM
Registered User
Thread OP
I have to agree with Miami Mike (and i'm the original poster in this thread)
Firstly I'm pretty good at electronics, still learning about flying and still learning about glkiders and still learning about varios and how to use them.
Having said that , I agree with Miami Mike that the speed of response of the thermal scout in tone mode is somewhat sluggish.
I noticed that even if I saw thew plane going down, the Thermal Scout was not indicating that and vice versa.
Thats not to say that the the output tones were not there; they were but they did not seem to correlate in real time with my observations.
I was using the transmitted signal and receiving it on a ground receiver.
I also noted that just lifting the plane a few feeta and ground level, should make the output tones 'go up" but that did not occur reliably.
Maybe we need to ask Winged Systems how they did their tests.
Robert
Jan 10, 2012, 03:48 PM
Addicted to lift
eosglider's Avatar
Found another place for the 433mhz TX and RX:
http://www.futurlec.com/Radio-433MHZ.shtml

Wonder how hard it would be to get an OpenAltimeter to do Vario Tone output... I'm going to ping Jony the maker of the OA. I know they use the Bosh pressure sensor and there might be an easy way to tap into it and output tone from it for Vario.
Jan 10, 2012, 10:47 PM
Registered User
Thread OP
The RLP434A is the receiver that I use and you can use TLP434A as the receiver
Despite the datsheets, I get about 250m ground range in suburbia and far more than that when the plane is sky high
Robert
Jan 13, 2012, 07:26 PM
Registered User
Thread OP
I wrote to Dave at Winged systems about the issues with the tone put put of the Thermal Scout
here is the reply he sent me (with his permission)
I really got an appreciation of the difficulties of designing a vario

Hi Robert,

Thank you for the email. It is timely; just this week we have been exploring an improved filter algorithm for the Thermal Scout output modes. More on that in a moment, first let me explain what you are seeing with the current version.

Any variometer design faces tradeoffs between sensitivity, response time, and stability (or noise immunity). We have tried to optimize these factors to provide the best performance for thermaling an R/C aircraft. As you may know, most audio variometers don't perform well in models. They tend to screech and howl with every touch of the stick or ripple in the air. While this quick response may seem to be what we want, in real flight it makes it almost impossible to distinguish a light thermal from turbulence or stick inputs. It works well in very strong, consistent thermals -- but for those you really don't need a variometer.

This is an issue in full-scale gliders as well. Many variometers for full-scale gliders have a 4-second average setting. This greatly reduces false signals and quiets the noise (which can drive you crazy). The cost for this stability is a slowing of the response time. Our model gliders get bounced around even more than a full-scale glider, so this type of averaging is even more useful. Unfortunately, the standard 4-second filter is just too long for the tiny thermals we sometimes go after.

After a great deal of flight testing we found that a 1-second filter seemed to work best in R/C gliders. The filter is adaptive so the apparent delay in response will vary from about one-half to one-and-a-half seconds. The down side is that it makes the response seem sluggish when you ground test the unit by lifting the plane over your head. It also gives weak and delayed responses when you wiggle the elevator to test it in flight (after all, this is the kind of stuff it is trying to filter out). However, I think you will find it quite useful in detecting and centering real thermals.

When searching for thermals it is best to set up a steady glide at a reasonable speed with as little control input as possible. The Thermal Scout will establish a solid baseline. When you encounter lift the Thermal Scout will respond with its minimum delay. If the lift continues the tone will continue or increase. When the tone drops, you know you have flown through the lift. This will give you an idea of the size of the thermal. Now, circle back around into the thermal you just flew through and let the tone guide you.

You can keep the delayed response in mind, however in real situations it doesn't really come into play Any thermal you can fly through in less than a second is too small to work or off to the side (you can turn back toward the high wing to investigate).

Using any audio variometer does take a little practice -- sort of brain training to learn to interpret the signals. We have done a lot of flight testing to optimize the output for thermal hunting (not ground testing) and make it easier to interpret the signals.

Have you tried the standard "tail wave" mode? While the audio tones are cool, many folks find the standard mode superior for finding thermals. It employes a much more elaborate filtering method to "signature analyze" the lift profile. As a result, it greatly reduces false signals and requires much less learning on the pilot's part. I always suggest that folks using the output modes give the standard mode a try. You might like it better.

Now, about the improvement. We are working on a change to the real-time output filter that could make things better. Our main focus is increasing stability -- so that random noise is less likely to give false indications (a steadier tone when the plane is not moving up or down). With that quieter background we may also be able to reduce the delay somewhat. We've done the analysis and are presently writing the changes into the code. We need to do some initial flight testing (unfortunately we currently are in a snow storm). I'll let you know how it goes. If it pans out, I'd like to send out some beta test units (to folks in better climates) before incorporating the change into production.

Sorry for the long-winded reply.

Thanks again,
Dave West
Winged Shadow Systems
[email protected]
www.wingedshadow.com
630-837-6553
Jan 13, 2012, 07:58 PM
2.1.9 Forever
Miami Mike's Avatar
Okay, I have issues with what he wrote, but I'm willing to wait and see what he comes up with. I currently don't consider the audio tone function of the Thermal Scout to be usable. I've flown with and watched other variometers, such as the Piccolario, and they work much better. I'm sure the difference is mostly in the programming algorithm so let's hope he can improve that.
Jan 17, 2012, 04:21 PM
Registered User
Sounds a little like it may be missing the "configurable silent neutral sink" mode of a competing product... I'm guessing it makes noise all the time?
Jan 18, 2012, 05:08 AM
Registered User
Thread OP
The Thermal Scout has two modes in the tone mode
One mode has tones for both lifting (rising tones) and sinking (falling tones)
The other mode allows one to turn off the tones for sinking

Its easy to read the manual on the Winged Systems site
Jan 19, 2012, 05:57 PM
Registered User
mark963's Avatar
I've had a chance to compare the "old" V2.1 and "new" V2.2 side by side... on my desk. During a one minute test, recording the two (in STEREO!) simultaneously, the V2.1 had 7 weak indications vs. V2.2 showing 1. The new version is definitely less noisy. It’s also pretty clear the unit is doing some interesting filtering to try to sort out what is typical bouncing around vs. real lift. Dave says version 2.2 is shipping now and upgrades are available.
Jan 26, 2012, 07:50 AM
fast
fmkit's Avatar
Quote:
Originally Posted by Miami Mike
The other modes, which are (1) rudder-wagging and (2) triggering an alarm signal in a radio with telemetry, are not as immediate and precise as you'd expect an audible tone to be; they're "Boolean", meaning that they can only indicate yes or no - you're going up or you're not. A variometer tone normally distinguishes between going up, going down, and holding altitude, and even gives you indications of relative rates of vertical speed.

My impression is that people are happy with the Boolean modes, but I'm skeptical about how well the variable tone mode works. I wonder if Winged Shadow Systems actually tested that mode with actual flights in a sailplane somehow. If not, it's beginning to look like it doesn't work as well as they assumed it would. If so, I'd like to know what sort of transmitter system they devised to listen to the tones.

For the same reason I did FM link, after using "boolean" UHF telemetry for few months I thought about analog indicator and here is homemade receiver and 40mW FM transmitter. If transmitting outside commercial 87-108MHz band range improves a lot. 30mW is good for almost one mile. The transmitter is based on this module with added gain stage and LowPass Filter so no interferance with my RC link (UHF)
I could use any receiver with Japan 76-87MHz band but made my own to display RSSI which is helpful to adjust TX antenna and locate downed plane
Now trying to connect acclerometer to fly really small flying wings that that my eyes hardly can see but with help of tones one can fly blind, even to make rolls and loops without looking at the plane

telemetry module with built-in FM (RDA5820 chip)

tx on my ugly flying wing:
Jan 26, 2012, 08:51 AM
Stuart
srnet's Avatar
Nice one.

I eventually got the data telemetry working on the Hope RFM42\RFM31 pair of modules (driven by PICAXEs) but found the range to be very poor.
Jan 28, 2012, 10:37 PM
Registered User
Mutchy's Avatar
DIY Variometer using Thermal Scout and Hobby King 5.8 GHz Tx and Rx

The system uses the Winged Shadow tone output fed into the audio channel of the Turnigy 5.8 GHz transmitter. The tone can be heard using the Turnigy 5.8GHz Rx and the Fat Shark adjustable earphones. Total cost about US$120 plus postage.

See the picture below to identify the components. See here: https://www.hobbyking.com/hobbyking/s...FRx%5FSet.html for the Tx/Rx set and here for the earphones https://www.hobbyking.com/hobbyking/s...phones%5F.html . The Thermal Scout is here: http://www.wingedshadow.com/thermalscout.html

The silver box with the larger antenna is the 5.8 GHz Receiver. The smaller silver box with the smaller antenna is the Transmitter. In the middle of the picture is an Orange FAAST 2.4 GHz Rx with its Turnigy UBEC and Rhino 2s LiPo power supply. At the end of the lead coming out of the 2.4 GHz Rx is the Winged Shadow Thermal Scout. The lead at the bottom of the Thermal Scout goes into the 5.8 GHz Transmitter. The earplug type headphones are the Fat Shark Adjustable . More batteries and leads appear in the picture, of course, to power the other bits and pieces.

Important things I learned so you can replicate this system, if you want to…….

There is discussion in the comments section of the HK website 5.8 Tx/Rx page concerning the identity of the correct leads fitted to the AV input connector. HK have sold some sets with the colours reversed. ie the leads are exactly opposite in colour to what they should be. I established that the earth pin on the 5.8 Tx is the one on the extreme left when viewed from the side opposite the heat sink. Audio input is the third from the left.

Attach the antenna before turning either the Tx or Rx on. The little dip switches for channel selection are all "off" when you get the Tx; they look like they are all "on" to the visually challenged observer (me).

The Fat Shark headphone cable has a 3.5 mm stereo plug fitted which does not match the AV Out socket on the 5.8 Rx. It has three contact bands compared to the four on the supplied harness. An adapter lead is necessary, as you can see, so that the white and red audio RCA phono sockets can be connected to the 3.5 mm plug. I made mine using a redundant audio lead from a TV and a 3.5 mm stereo line socket from Jaycar ($2.00)

The Thermal Scout needs to be plugged into a channel on your R/C Rx with a switched output say the "gear" switch on your R/C Tx. You can use this for programming the output mode of the ThermalScout or you can just set up a battery and switch plugged directly into the TS. This is so that during the climb under power you don't transmit the tone. On my Er9x I will mix this channel with throttle so that when the throttle is "on" the TS is "off" and vice versa. It has four output modes depending on what you want and what R/C gear you own. See the link to the data output mode instructions at the bottom of the text here: http://wingedshadow.com/thermalscout.html I used the third option "Tone Output" with tone active in lift and sink. Programming is done by switching the TS on and off five times in a row within four seconds to enter programming mode and then switching the unit off when the appropriate number of tones are heard - in my case three tones. Fairly straight forward; see the TS Instructions.

The output of the TS is 0.2 to 3 volts peak to peak with middle C tone being 1.6 Volts. The input to the 5.8 Tx is specified as 0.5 to 2.0 Volts peak to peak. Not being sure whether a voltage divider would work to limit the TS input to 2 volts I directly connected the TS to the 5.8 Tx and it worked. To see if it works cup your hands around the TS and gently suck or blow to change the local atmospheric pressure around the variometer sensor. Be careful not to raise the voltage ie the tone/voltage could go too high and risk damaging the 5.8 Tx audio input circuit. Having proved the whole system works I fitted a home made voltage divider between the TS and the 5.8 Tx. It reduces the peak voltage by two thirds. See the last picture. This had the effect of lowering the neutral tone but did not affect the performance. i.e. the interrupted tone commenced at the neutral point when the atmospheric pressure was lowered by sucking. I further tested the unit by sticking everything in my pockets and "running" up and down a flight of stairs. (not easy for a 68 year old with two prosthetic hips!) The altitude change was about 8 feet at a rate of about 2 feet per second. There was a delay of about 3 seconds during the ascent or descent until the sensor noticed the change and the tone changed. Everything worked satisfactorily.

The 5.8 GHz Tx antenna is annoying and not so good. It uses "reverse SMA" fittings which are not commonly used (well here in Oz anyway) and its permanently stuck at right angles to the Tx body (whereas the Rx antenna is articulated like your 2.4 GHz R/c Tx). Installation in my carbon fibre fuselage required the manufacture of a dipole aerial with the proper fitting. I used a reverse SMA crimped cable fitting and a short length of coax cable. I bared 12.5 mm of the inner core at the end and folded the outer shield back along the outside of the cable . I then crimped a piece of one eighth inch (3 mm) internal diameter aluminium tube 11 mm long over the exposed outer shield wire. I then covered the end with heat shrink. This is the same as what is inside the "Rubber Ducky" aerial. See here for the details: http://martybugs.net/wireless/rubberducky.cgi

I compared the range of the supplied (rubber ducky) antenna and with the dipole antenna on the ground. The dipole type has better range than the original. I placed the transmitter on top of a shoulder height pole with a Futaba Tx and an Orange FAAST Rx to test the ability to switch the vario off and then on as I drove further away. The "as supplied "ariel gave me about 700 metres range before the signal was lost. My dipole aerial gave me at least 800 metres range and was still receiving when the Rx battery died. In both cases the 2.4 GHz Futaba FAAST R/C system was out of range well before the Turnigy 5.8 GHz system.

For more information on Tx and Rx Antenna performance see these links:
https://www.rcgroups.com/forums/show...1426685&page=7
https://www.rcgroups.com/forums/show...1516397&page=5


I tested the system in my carbon fuselage electric glider with good results. The 5.8 GHz Transmitter antenna sticks up from the top of the fuselage just behind the wing. See photo below. I started with the 5.8 GHz Rx in my jeans pocket with the aerial sticking up but received less interference with it dangling from my pocket down beside my leg. I'll take a stake with me next time and hang it from a nail as high as I can get it within the limitations of the earphone leads. There were no thermals but some patches of air were more buoyant than others. The Thermal Shadow system worked continuously and perfectly. It responded to stick movements ie "stick thermals" as it is not a total energy system as used in full size gliders. To make a total energy compensated system would require installation of the sensor in a flask with a Braunschweig tube or similar pitot head. http://en.wikipedia.org/wiki/Variometer The Turnigy system worked well albeit with some crackling and popping which I expect will be fixed with a better Rx position ie not in my pocket!

Mutchy
Last edited by Mutchy; Jan 28, 2012 at 10:46 PM. Reason: Typos


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