I am fairly far along prototyping a new device that allows you to set airspeed from your transmitter and have the plane maintain the desired air speed automatically. It consists of a pitot tube and an electronics box connected with the pitot tube by two air tubes, the receiver with three servo leads and a servo plug. One of the leads plugs into the elevator servo outlet on the receiver and the elevator servo plugs into the plug on the box. The two other leads plug into spare plugs on the receiver, one that will connect with a two-position switch, the other into one will be connected with a slider.

On the transmitter you will use the switch and slider. The switch is used to activate the device and the slider is used to set the desired air speed. I would set one end of the slider to minimum sink speed and the other end to 2 * max L/D. The speed limits would be rough set with pots on the device as would the maximum elevator deflection. Fine setting would be done by adjusting the end points of the slider.

The actions of the device can always be overridden with the elevator stick input.

The idea is that you would launch with the device switched off and once your are off the line you would activate it and set max L/D if you launch into lift. If you need to search for lift you would set max L/D or a higher value if you are searching up-wind. Once you hit lift you would set the slider for minimum sink. On landing it could also prove useful by helping fine tune flap and spoiler compensation.

So why would you want one of these? It should make you fly more efficiently, especially if you are at altitude. More importantly, possibly, is that it could save your plane if you lose sight of it.

So what kind of interest is there in such a device? Also, is it worth $200-$300?

I am going to install it in one of my planes once we get to spring.

Anker

This I would have to try.
Sign me up.
Regards Dean

This is a fascinating topic. I set out to build one myself after a long chat with Dan Edwards and the ALOFT gang at Cal Valley in 2009, given that airspeed control was one of many systems that they had on their ship. The problem is that its legality in AMA and FAI is a really large grey area. A case could be made for it either way. I ultimately decided that it would be deemed illegal and abandoned my project.

My thinking is that if a microcontroller or an analog circuit is making the decisions to add up elevator or down elevator and is controlling the servo then the guy with the transmitter isn't making those decisions thus not controlling that portion of the flight despite the fact that he can override it.

A next step could easily be to send the vario data to the microcontroller and then control the glider's airspeed based on whether you're in lift or sink. Speed to fly theory would be programmed in to make sure the model flies at xxxx speed when in 1 kt of sink..or 3 kts...perfect dolphin flying at the flip of a toggle switch giving this part of pilot decision making to a circuit board as well.

A similar system then gets attached to the ailerons or rudder servo which is fed information by a GPS now allowing the "pilot" to set his course to the next turnpoint knowing that the glider will perfectly crab as necessary to hold it's course while holding the perfect airspeed for lift and sink.

This isn't a far fetched fantasy as any of the guys that were at Cal Valley in 2009 witnessed and can attest to. It's already been done and to a much greater extent.

This path is likely to make flying XC competitively without the units as much of a problem as trying to fly XC competitively without a vario. Allowing or disallowing microcontrollers to make onboard decisions and alter the flight accordingly will redefine what XC will be in the future.
New gliders can and do make old gliders obsolete though, so is this any different ? My take is that it is because the unit is making decisions for the servos and control surfaces rather than (or in addition to) the pilot. It becomes a contest for the programmers rather than the pilots.

I'd recommend that you ask a dozen CD's that know speed to fly theory if they'd allow it in their contest and go from there in an effort to minimize controversy.

Mike

The legality issue is one I have thought a lot about and its great that you brought it up.

The trouble with banning these devices is that its really difficult to determine whether a plane has one installed. With varios the telemetry receiver would be a giveaway, but with "autopilots" there's no need for telemetry. Sensors have become incredibly small and you can get complete microcontrollers with digital and analog interfaces on a single chip. In this case the pitot tube would be a dead giveaway, but I could just as easily have designed it to use GPS instead, and it would be completely hidden inside the fuse. A really good electronics engineer could hide such a device inside the receiver case!

Holding back technology only works in a totally dedicated community like Nostalgia. Everywhere else there is a technology race and in every case the guy with the most money to burn can gain some advantage with superior equipment. If we want pure pilot skill to be the only basis for winning, then the only way to go is to eliminate any and all possible technology advantages. Possibly by having a lottery before each contest determining who gets to fly what plane.

The AMA requires that the rules for the contest be published in advance, so either FAI and AMA have to be much more direct, or the CD community must start including rules about "autopilots" in the contest descriptions. A CD for an AMA sanctioned event cannot make up a rule on the fly at the contest.

Another argument is that the device can be completely mechanical. One of our club members experimented with such a device controlled by a vane. Is that an "autopilot", or is it just plane design?

Anker

This reply is somewhat related in that it pertains to the technological side of our sport.

I'm still hoping to see someone develop a split GPS system. One that takes the GPS location of a plane and transmits that information to an in-car Magellan Roadmate type of device. The purpose would be to have visual display of the plane, in relation to the road, so you can "see" where it is and when the plane has made the turnpoint.

Now, I'd buy one of those. As a matter of fact, I'm prepared to send a deposit to anyone who's working on such a device.

Dudley

Yes...all good points and more questions. The recent interests in UAV from the FAA on down to us seems to have separated autonomous from autopilots by the term "ability to navigate to a location". If that is or becomes the line at which we can not cross in AMA competition (autopilots are ok) then what you have proposed and the path that I outlined that may follow afterwards is all fair game. A glider on a course is not a glider flying to a location.

I agree, not allowing technology to evolve is stagnation, be it in improved aerodynamics, improved structures or improved electronics. No one that I've seen is competing with the old Ace thermal sniffer, so improvements in electronics have deemed it obsolete for competitive flying.

If there's a need for a class to defy "the deepest pocket wins" (assuming it became that) then a one design contest may become popular in addition to the open class.

I'm looking forward to seeing how the interest and use of your product to be evolves.

Mike

Originally Posted by Dudley Dufort

This reply is somewhat related in that it pertains to the technological side of our sport.

I'm still hoping to see someone develop a split GPS system. One that takes the GPS location of a plane and transmits that information to an in-car Magellan Roadmate type of device. The purpose would be to have visual display of the plane, in relation to the road, so you can "see" where it is and when the plane has made the turnpoint.

Now, I'd buy one of those. As a matter of fact, I'm prepared to send a deposit to anyone who's working on such a device.

Dudley

This is incredibly easy. In the plane you have a NMEA 0183 compatible GPS with a serial interface to a XBee 900 MHZ tranceiver. On the ground you have another XBee 900 MHZ tranceiver with a serial to USB interface. This feeds the NMEA 0183 to Google Earth through a program called Earth Bridge. The only caveat is that you need to have PC with an active Internet connection for Google Earth to display the map. Not too difficult if you have broadband internet service.

Hardware: MediaTek MT3329 GPS 10Hz + Adapter Basic from diydrones.com $37.95. 2 * XBee 900 MHZ from Digi-Key @ $38 = $76. FTDI cable ~ $10.

Software: GPSGate Express 0$ or GPSGate Standard $39 plus batteries and switches.

Can be wired up in less than an hour.

Anker

Anker

I have always thought that next to a variometer, airspeed information would be the next most useful information for XC flying. However I do not believe a device such as what you are proposing should be allowed in XC competions. There is a big difference between airspeed information(telemetry) and autonomous airspeed control.

Telemetry is nothing more than information transmitted from the glider to the pilot. It is still up to the pilot to use that information and fly the glider. I have come to the conclusion that any amount of telemetry is OK. Vario, GPS, airspeed, altitude etc. are all OK with me. Its just information.

On the other hand I do not think autonomous control of any control surface should be allowed. Once the pilot gives up control to a device on any or all of the control surfaces he is really no longer flying the glider. If we are not flying the glider then what is the point of the competition?

The device you are proposing certainly would be a great help in maximizing flight performance and I might even want to purchase one for use in flight testing. But I believe it crosses the line over what should be allowed in our XC contests. How about a device that provides audio airspeed announcements?

This topic is really important and we need to have further discussion and then make a definitive ruling on all telemetry and autonomous controls.

John

Originally Posted by John Ellias

Anker

I have always thought that next to a variometer, airspeed information would be the next most useful information for XC flying. However I do not believe a device such as what you are proposing should be allowed in XC competions. There is a big difference between airspeed information(telemetry) and autonomous airspeed control.

Telemetry is nothing more than information transmitted from the glider to the pilot. It is still up to the pilot to use that information and fly the glider. I have come to the conclusion that any amount of telemetry is OK. Vario, GPS, airspeed, altitude etc. are all OK with me. Its just information.

On the other hand I do not think autonomous control of any control surface should be allowed. Once the pilot gives up control to a device on any or all of the control surfaces he is really no longer flying the glider. If we are not flying the glider then what is the point of the competition?

The device you are proposing certainly would be a great help in maximizing flight performance and I might even want to purchase one for use in flight testing. But I believe it crosses the line over what should be allowed in our XC contests. How about a device that provides audio airspeed announcements?

This topic is really important and we need to have further discussion and then make a definitive ruling on all telemetry and autonomous controls.

John

A couple of counter arguments, John,

If I am selecting the desired air speed from a slider I would argue that I am still in control. Rather than setting an elevator position I am adjusting some other control. The plane isn't selecting the air speed, its simply holding the one the pilot selected. Autonomy would be when the electronics in the plane selected an air speed from on-board sensors. The pilot still has to select the appropriate air speed for the conditions, difficult when flying up and cross-wind, find thermals and stay in them.

The next argument is one I brought up earlier: It is possible to build a purely mechanical airspeed control device using a vane or some other mechanical airspeed sensor and have it adjusted with a servo. Is that any different from any other control we currently have? With a far enough forward CG the elevator is close to operating as a pure airspeed control. Should that be banned? Another mechanical airspeed control could be built with a servo-controlled CG adjustment. We all know the plane will fly like a dog, but on a sufficiently stable plane the elevator becomes an airspeed control.

My final argument is that such a device will advance the performance of gliders, which is desirable. It would also improve the safety by preventing some loss of control crashes, desirable again. And it would make the sport easier for new entrants by eliminating one of the biggest challenges, air speed management at high altitude, again desirable.

An argument against telemetry is that it causes several safety issues: Visual telemetry forces the pilot to take his/her eyes off the plane, and audio telemetry makes it harder for the rest of the team to communicate with the pilot.

Great discussion!

Anker

I wouldn't do a lot of development until after the FAA's NPRM is published.

tk

My sentiments, exactly. Allow all of the telemetry data the pilot can swallow but no automated movement of control surfaces.

We need to be really careful about even discussing any kind of autonomous aircraft with the sport already under close scrutiny by the FAA.

Anker,

Spend your time on a ground-based flight computer w/ speed-to-fly guidance for the pilot. I think that's where the real win would be. PM me if you'd like to compare notes.

Mike

Originally Posted by John Ellias

Anker

I have always thought that next to a variometer, airspeed information would be the next most useful information for XC flying. However I do not believe a device such as what you are proposing should be allowed in XC competions. There is a big difference between airspeed information(telemetry) and autonomous airspeed control.

Telemetry is nothing more than information transmitted from the glider to the pilot. It is still up to the pilot to use that information and fly the glider. I have come to the conclusion that any amount of telemetry is OK. Vario, GPS, airspeed, altitude etc. are all OK with me. Its just information.

On the other hand I do not think autonomous control of any control surface should be allowed. Once the pilot gives up control to a device on any or all of the control surfaces he is really no longer flying the glider. If we are not flying the glider then what is the point of the competition?

The device you are proposing certainly would be a great help in maximizing flight performance and I might even want to purchase one for use in flight testing. But I believe it crosses the line over what should be allowed in our XC contests. How about a device that provides audio airspeed announcements?

This topic is really important and we need to have further discussion and then make a definitive ruling on all telemetry and autonomous controls.

John

Its interesting to hear the sentiments of the group. I do feel a bit like I am getting into "flogging a dead horse" mode, but here's one more point:

I don't understand is how getting a telemetry data feed that tells you your current airspeed and you moving the stick to adjust it to your desired airspeed is any different from adjusting a dial to have the plane maintain the desired airspeed? All you have done is insert a "meat servo" into the circuit. Any dummy can do the first, so why not allow the second with the added safety advantage.

Anker

PS I am going to build it anyway because A) its fun and B) I have already bought all the pieces!

The synapses firing between the pilot's ears is the difference. The pilot ultimately has to be responsible for the control of the plane.

For example, let's say I am a terrible pilot and interpret the airspeed or variometer reading incorrectly (very real cases). I won't make the right moves in flying the proper speed-to-fly for the conditions, center a thermal quickly or at all, etc, etc, etc.

You, on the other hand, are a great pilot and have practiced flying with the vario and other stuff and know how to interpret the information and make the correct control inputs to fly more efficiently (this is what you're after, right?).

If you take the differences (subtle or not-so-subtle) between you and me as pilots away, you're testing the ability of the guy that cooked up the system and not the pilot.

I'd much rather fly against a real person than a robot. Ask the guys that flew against the ALOFT team at Cal Valley. Not a real even match as I recall...

I think we all like your enthusiasm and technical chops but something about it just feels like what you suggest takes the real flying out of the sport,

Mike

ps: I'm actually quite thankful that you started this thread. I was toying with putting a rudder gyro (to aid in maintaining course) in my GPS triangle racing ship but "you" have talked me out of it

Originally Posted by Anker

Its interesting to hear the sentiments of the group. I do feel a bit like I am getting into "flogging a dead horse" mode, but here's one more point:

I don't understand is how getting a telemetry data feed that tells you your current airspeed and you moving the stick to adjust it to your desired airspeed is any different from adjusting a dial to have the plane maintain the desired airspeed? All you have done is insert a "meat servo" into the circuit. Any dummy can do the first, so why not allow the second with the added safety advantage.

Anker

PS I am going to build it anyway because A) its fun and B) I have already bought all the pieces!

I'd like to see it just to see if it works. My own airplanes are very well dialed in with flight modes for each speed setting. It would be nice to see if the GPS data on the run matches the pitot tube, and how close it is to the model.

Originally Posted by G Norsworthy

I'd like to see it just to see if it works. My own airplanes are very well dialed in with flight modes for each speed setting. It would be nice to see if the GPS data on the run matches the pitot tube, and how close it is to the model.

GPS data will only ever match the pitot tube data if there is no wind as the GPS only provides ground speed and not airspeed.

- Bob -