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Feb 17, 2004, 02:57 AM
Registered User

Automated Landing system for RC

Hi guys

I am currently a senior and it's project time.

Our group has decided to construct a system that will land a RC plane. It will be able to detect the altitude and keep the plane level in flight as well. The only control that the pilot will have is rudder control so that the direction is controlled by the pilot.

Now I know that there is a co-pilot system availabel but it only controls level flight. If I am wrong please let me know.

The system will be plugged into the landing gear channel so that it can be toggled on and off at the pilots demand.

We are looking for comments and other ideas and if there are people interested in something like this.

Some more detailed info:

The system will have a pressure sensor that will detected the altitude this in return will be feed into a micrprocessor that will have a program written to make sense of what the pressure sensor is detecting. It will have two small ceramic gyros the will aslo be incorporated into the circuit. These will detect the pitch and roll and will be adjustable so the the pilot can adjust the limits. We plan the the total thing will weight a couple of ounces be no larger than 3 X 4 x 1 inches. We are not sure exactly of the sizes and wieght since we haven't started building yet. The wieght can decrease even more since the prototype will only be made from regular components nothing micro. We paln it will run from the same battery pack that the plane would use since we predict it will draw small amount of power or on a seperate 9V battery.

We would apperciate some feedback or other questions.



We plan to show progress on this forum if there is interest and to show the final video of it working.
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Feb 17, 2004, 04:50 AM
(aka Cliff Lawson)
Wright Flyer's Avatar
You may have a job making a barometric altimeter accurate to more than about +-20ft.
I guess that it goes without saying that if it thinks the ground is -20ft from where it is you're going to dig a big hole!

The CoPilot can help in landing as well as level flight in that you can use just the throtte to land but I guess you want to add the extra bit that auto-controls the throttle based on measured height? Have you tought about ultrasonic parking sensors as found on most top range cars these days. It may be a better way of judging height then trying to do it barometrically.

Feb 17, 2004, 05:32 AM
Long-Time Member
James Frolik's Avatar
Cliff in the preceding post states my similar thoughts. Ten or 20 feet to a real plane such as a B747 could be the difference between a smooth landing and, for a model plane, a hole in the ground with scattered wreckage.

Some type of ground sensor for those last 10 feet or so would be needed in a model since barometric pressure -- and even a GPS -- would not guarantee a gentle enough sink rate within those few remaining feet before touchdown.
Last edited by James Frolik; Feb 17, 2004 at 05:34 AM.
Feb 17, 2004, 07:21 AM
UN Earth peoples true enemy
treehog's Avatar

Tough nut to crack

The choise of plane will decide sucess or failure
The size of the task is very complex

There were threads on subject in model sience forum

GPS seems to be the normal way these projects are tackled as they seem to work very well as appossed to barometer

I suggest go with a non aerlion large light weight E glider and GPS
and attach retract undercarrage to act as drag

See if you can get autopilot hal or similar to keep plane level and when undercarrage goes down planes sink rate should cause it to land

Good luck will watch the thread as I could do with an automatic system which returns the craft back to base if I flew out of range of RC

Last edited by treehog; Feb 17, 2004 at 07:23 AM.
Feb 17, 2004, 12:47 PM
Zen Flying Master
AUBrian's Avatar
Okay, maybe a dumb question, but does it need to be completely automomous? What I mean is, can there be some sort of transmitter that it can use to home in on? If you think about it, for a real plane, they'd need one so they don't overshoot the landing or come up short....I mean, bringing it down gently is great, but if you're 1000 feet past where you wanted to be down, it does no good. It seems like you'd need some sort of sensor at the start or end of the runway.

Otherwise you don't need a pressure sensor, you just need a gyro to keep it at a constantly slowly descending angle....that would actually be safer than a pressure sensor......something that just shuts the motor off and keeps it at a proper flying angle to let the plane come down on its own. Then you're basically doing a glider-type or dead stick landing, with slight computer help.....

In fact, if you wanted to even throw in something that actually inputs throttle, maybe a pitot tube that you can use to make sure it's going the correct landing speed, and can input throttle accordingly. What do you think?
Feb 17, 2004, 01:11 PM
registered user
DNA's Avatar
There is a member posting in the Aerial Photography forum who is designing an altitude sensor that he says is accurate to 1 foot.
Feb 17, 2004, 02:21 PM
Registered User
There are sensors now on electronic measuring tapes that are accurate to parts of an inch and good to about 30 ft. Used for quick estimating of room sizes ect. Don't know if they will do a continuous changing read or even if they will work off a moving target though. Might be worthwile investigating.
Feb 17, 2004, 02:31 PM
Ascended Master
Sparky Paul's Avatar
The FMA Co-pilot™ makes duck-soup of landings!
Align with the runway, cut the power and it lands. It doesn't flare but it lands softly.
The guys that use them in the club are reluctant to turn them off!
On the L-1011 AutoLand™ system, the plane would intercept the localizer beam several miles from the runway threshold. It would fly this beam until it intercepted the beam for the glide-slope, at which time it would begin to descend. At 50 feet, the plane would begin to flare to touchdown at 2 or so feet/sec. The touchdown point was set at about 1200' from the approach end threshold.
We found that a slower sink rate could result in the wheels not touching the runway.. this would then not tell the spoilers to deploy and the plane would float quite happily in the flare attitude until someone noticed.
A firm landing assured the squat switches in the main gear would make, and the spoilers then auto-deploy for aero braking, and the stabilizer would push the nose down.
Note the human pilots could land the plane at sink rates of 6 inches per second.. so soft you hardly knew you'd landed.
Feb 17, 2004, 05:08 PM
Visitor from Reality
Originally posted by Sparky Paul
Note the human pilots could land the plane at sink rates of 6 inches per second.. so soft you hardly knew you'd landed.
from my flying experiences over the years, I think they must have all retired

Feb 17, 2004, 05:34 PM
Electric Coolhunter
Thomas B's Avatar
A much better micro altimeter system would be an ultrasonic sound one, like the old instant cameras used to use for range finding. This was used in some of the man powered aircraft projects due to the good sensitivity at low altitudes and very low weight. (ounces)
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Feb 17, 2004, 07:41 PM
Moths do not fly inverted
LJH's Avatar
I'm with Dereck.....Either all those guys have retired or the airlines I fly on only hire old NAVY guys who like to know when the wheels have touched tera firma.

Feb 17, 2004, 08:59 PM
Frequent flyer
GPS seems to be the normal way these projects are tackled as they seem to work very well as appossed to barometer
gps would be almost unuseable for this project. a standard 12 channel gps rx usually only has accuracy of +/- 50 ft on altitude for a moving object, WAY too much... My WAAS gps reciever can get down to +/- 10 feet or so on altitude, but that is assuming a good lock on the geo sat and also the fact I'm only a couple miles from the nearest WAAS station. (you must be within 300 miles from a station, there are only 24 in the nation) also, most gps engines only update once a second. try closing your eyes for a second while landing, then do that continously.
Last edited by rkramer; Feb 17, 2004 at 09:08 PM.
Feb 17, 2004, 09:23 PM
Ascended Master
Sparky Paul's Avatar
Originally posted by LJH
I'm with Dereck.....Either all those guys have retired or the airlines I fly on only hire old NAVY guys who like to know when the wheels have touched tera firma.

While working on the Tristar during the Autoland development period in Systems,
my boss mentioned to the pilot, A.J. Peterson
"AJ, I'd sure like to land this thing."
AJ replied.. "SO WOULD I!"...
Doing a zillion autolands, flying for hours and never getting out of the traffic pattern at Palmdale could be booooring!!!
AJ had F-104, U-2 and SR experience, and really didn't care for this hands-off flying.
Feb 18, 2004, 05:02 PM
Registered User
There is a system that is used with gps that makes it much more accurate and has been used for years by modified crop duster planes in california. They were dropping frozen irradiated fruit flies in very accurate grid patterns to control the population. This system relied on first setting a bearing and location as reference point and then worked with gps to relay info relative to that poisition. I will try to find out a reference for it and will post.
Feb 22, 2004, 02:49 AM
Registered User
Thanks to everyone for the feedback.

After reading the current posts we have changed our plans on some of the compononets. We are currently playin around with a tape measure that measures length ultrasonicaly and plan to get a cheap camera and see if we can use the auto focus mechanism some how to determine the altitude.

GPS is a good though but we had alredy ruled that out because of the accuuacy that is need for that idea to work. We are also going to use something to determine speed. Our idea was to write a program that would take all the data from the sensors and apply a signal to the speed controller on the amount of speed that should be used but this most likly wont work either. Someone posted the pitot tube which is interesting or we might pick up a acclerometer to determine speed.

According to our project schedule we start at the begining of March but we got a headstart and started picking a couple of items.

The plane that we plan to use a simple trainer something electric LHS has a couple of choices includeing premade models that were previously owned.

Once again thanks for the input and if there any comments please post a reply.

Group #7