UAV Project

[winterhank]

Hi all.
My 12 year old son and I are embarking on a science project with the ultimate goal of demonstrating autonomous flight. (We are currently active in RC flight - 3D, aerobatics, warbirds).

Inpsired by Workshop's and Icebear's posts, we have already purchased a Sr. Telemaster (ARF) and a Genoah G20 Gas engine to mount it to.

To be honest, I feel that the G20 is not a good match and have to rethink the powerplant for the Telemaster. Our goal was duration (1.5 hrs aloft) and thought the G20 would be perfect as it sips gas but found that the electronic ignition sucks batteries which kills the duration aloft idea. There are also weight concerns.

I have a new Saito 100 which might have to do.

We also want to grab telemetry from the plane and are seriously looking at RCATS with GPS. We also want to install a PicoPilot autopilot for the waypoint routing.

One question we had was if both GPS units would be required for the PicoPilot and the RCATS. Seems like a waste to have both of these units aboard.

If you kind folks have opinions or ideas, we sure would appreciate it.

We are excited about this project and cannot wait to get started!

Thanks!
Hank

[winterhank]

anyone out there?
any opionion?
everyone leave? I showered.

[JeffElecRC]

Winterhank, I'll chime in with my totally unexperienced opinion. Hopefully I'll say something wrong, and whoever decides to correct me will give you more info too. :D

Anyway. I can't address your airframe question (I'm an electric guy), but as far as the PICOPILOT goes, correct me if I'm wrong, but it can be mated with an optional telemetry modem (I believe they use the Maxstream Xtend line of radio modems). This will display your location on a moving map on a laptop. So I dont see you needing two GPS's. IF you just want to play with GPS and telemetry before you get the picopilot, then you could probably buy their GPS and the maxstream modems and connect them up stand-alone. Use a commercial map software on laptop to view the plane's position.

BTW, Is this the 12' telemaster you got? AKA Balsa Overcast?

Regards,
Jeff

[icebear]

Hank,

Interesting project!
I agree with Jeff - you could use the Pico GPS and a modem if you want to downlink data. If you want to go with the RCATS - check the specs of their GPS, the Picopilot GPS outputs data at 4800 baud.
Good luck and keep us updated!
/icebear

[winterhank]

Guys,
Thanks very much. I think I'll go with the PICO Pilot and downlink the telemetry from the PICO setup. I guess the airspeed and heading info is downloaded from the GPS? I think that is where I'm getting confused. I was hoping to get RPM, Airspeed and temps as well so might have to do both.

The Telemaster is the 91" inch model I believe. I decided to go ahead and cut the nose of it off to mount the G20. I'll have to shore up the firewall a bit.

Regards,
Hank

[kd7ost]

Hi Winterhank,

That is really a bummer about the G20. I saw that engine come out recently and was dismayed to see it didn't have a magneto ignition. I don't know how committed you are to the process but it sounds like your in pretty deep.

A G26 has a magneto ignition and fly's a Rascal 110 very well. I sold mine but you might talk to Curt at Flightgear. http://baron.flightgear.org/~curt/Models/Special/Rascal110_2/
I think they're flying a glow engine version as well at the university.

I would go with the Zenoah G38 and a spring starter. http://www.chiefaircraft.com/rcmsec/Models/Engines/Zenoah/Zenoah.html
Or a Fuji BT32B. It's supposed to be easy to hand start. I use the BT32A with a spring starter. http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXGAT1&P=ML

The bigger gas engines are hard to start without a pretty hefty starter and lots of battery current. A spring starter makes it easier to start at the field. Less gear to lug around.

I fly a home brew design with a 1 quart gas engine and at full speed will get 1 hour duration. With a 50 Oz tank and a 50 percent throttle setting you should make several hours easy.

These are just some of our experiences. Your mileage may vary.

Dan

[workshop]

Here's my understanding....

The GPS serial data streams off from the GPS receiver; where you pipe that data is up to you... ;)

Right now, I'm just sending the data to the PicoPilot but I can "Y" the serial stream to an OSD (i.e. Inspire) and/or to a radio modem (maxstream, etc.) for downlink.

I'd think that MOdulating the 4800baud serial stream and sending it down the audio channel of the video transmitter (where it can be DEModulated back to serial data) would be a slick way to do it but although others have pondered this concept, I don’t believe anybody has succeeded. The audio modem in this application would be simple much like the 9600baud modems of telephone yore!

Jeff

p.s. Hey Dan, I’ll upload some of my crop video soon (when the heat wave is over – Woodland Hills has been over 110 for the last five days – 60 people in California have died from the heat so far). I have some video stills from the last trip; I’ll dig ‘em up.

Flying from dusty, dirty, hot, sweaty, furrowed, obstacle ridden pumpkin fields with thousands of dollars of r/c gear sure is exciting!!! Each landing is like winning an Olympic Medal! I see why you like this so much. I’m too much of a glutton for punishment to be sarcastic… :D

p.p.s. I can stay aloft for 1.5 hours with a $900 battery pack. :p

p.p.p.s. Now if I could only afford a $900 battery pack. :mad:

[kd7ost]

p.s. Hey Dan, I’ll upload some of my crop video soon (when the heat wave is over – Woodland Hills has been over 110 for the last five days – 60 people in California have died from the heat so far). I have some video stills from the last trip; I’ll dig ‘em up.

Flying from dusty, dirty, hot, sweaty, furrowed, obstacle ridden pumpkin fields with thousands of dollars of r/c gear sure is exciting!!! Each landing is like winning an Olympic Medal! I see why you like this so much. I’m too much of a glutton for punishment to be sarcastic… :D

p.p.s. I can stay aloft for 1.5 hours with a $900 battery pack. :p

p.p.p.s. Now if I could only afford a $900 battery pack. :mad:


That sounds great Jeff. I've been pretty swamped and haven't done much building or AP flying at all. I'm away from home about 50 percent of the time.

I just love it when you're bent over the plane, fueling or checking and the sweat runs into your eyes. People think your crazy. You start liking the wind when you fly just to have the hot air flow. My biggest thing to train, literally, is just shooting touch and goes. Many, many, many. It's just like you said. It's like a carrier landing every time. It's hairy but you have to land. I have a lot of really remote rural roads. I fly from them just to stay dialed in to that.

I know it's hot down there. We have a couple guys from work on a fire down there. 114 in the daytime and 90 to 95 degrees at night. That's horrible. I don't have it that bad. Good luck and try to stay cool. ;)

Dan

[Mr.RC-CAM]

I'd think that MOdulating the 4800baud serial stream and sending it down the audio channel of the video transmitter (where it can be DEModulated back to serial data) would be a slick way to do it but although others have pondered this concept, I don’t believe anybody has succeeded. That is a popular APRS telemetry technique. Google "TinyTrak".

Also, the audio bandwidth is wide enough on many video systems to support a GPS's RS-232 without any modulation. It is a cool trick that only requires an audio attenuator on the Tx end and a data slicer circuit on the Rx end. But, the TinyTrak and other devices like it work well. And, there are plenty of soundcard drivers that will allow a notebook PC to act as the software based modem without any hardware beyond an audio cable.

[workshop]

That is a great downlink solution and so simple... :rolleyes:

For the groundstation:

I guess one needs to demodulate the audio (software modem as you suggested) and get the position information into display software. I guess there is generic groundstation software out there. I wonder if Mapsource (I'm sure it must) can fill this role. I'll start looking into it.

What modem software do you use (if any)?

Jeff

[Mr.RC-CAM]

I'm not using the APRS services. My telemetry is on-screen rather than via a dedicated data channel.

BTW, if you search "APRS" on the rc-cam.com forum you will find some interesting info on it. It's been awhile since it has been discussed; the experimenters there have been there, done that, as they say. The discussions may be old, but the info is still valuable.

[winterhank]

Hi Winterhank,

That is really a bummer about the G20. I saw that engine come out recently and was dismayed to see it didn't have a magneto ignition. I don't know how committed you are to the process but it sounds like your in pretty deep.

A G26 has a magneto ignition and fly's a Rascal 110 very well. I sold mine but you might talk to Curt at Flightgear. http://baron.flightgear.org/~curt/Models/Special/Rascal110_2/
I think they're flying a glow engine version as well at the university.

I would go with the Zenoah G38 and a spring starter. http://www.chiefaircraft.com/rcmsec/Models/Engines/Zenoah/Zenoah.html
Or a Fuji BT32B. It's supposed to be easy to hand start. I use the BT32A with a spring starter. http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXGAT1&P=ML

The bigger gas engines are hard to start without a pretty hefty starter and lots of battery current. A spring starter makes it easier to start at the field. Less gear to lug around.

I fly a home brew design with a 1 quart gas engine and at full speed will get 1 hour duration. With a 50 Oz tank and a 50 percent throttle setting you should make several hours easy.

These are just some of our experiences. Your mileage may vary.

Dan

Dan,

I decided to go ahead and use the G20. Yeah, I'm wishy washy.
Found a 4200ma battery that should keep the ignition going for at least 2 hours so I believe that is a fix for the duration.

That is a sweet airframe you are using. Did you design and build that? Definately looks UAVish.

Workshop: thanks for the Y cable suggestion. That will work! I will be using maxstream modems so it is a no brainer to just feed the pico gps into the maxstream.

Haven't come up with a ground station solution for tracking. Still researching everything I can find.

Thanks guys.

Hank

[kd7ost]

Dan,

I decided to go ahead and use the G20. Yeah, I'm wishy washy.
Found a 4200ma battery that should keep the ignition going for at least 2 hours so I believe that is a fix for the duration.

That is a sweet airframe you are using. Did you design and build that? Definately looks UAVish.
Hank

The G20 is a good engine and should give you what you need with the 4200ma battery.

That plane is one I designed and built. Not the most effecient design but it's been around a few years just plugging away for me. Good luck and keep posting pictures here. This is all fun stuff. :D

Dan

[Birddog]

I'm glad I found this thread... I'm doing almost exactly what you are doing Hank and with the same airframe. I'm going to however mount a smaller gas engine on my 94" Telemaster. I have a Supertigre 90 converted to gas with CH electronic ignition that supposedly sips fuel and should give good endurance. This will not be a fast moving aircraft but I think it will serve it's purpose. Any thoughts?

Here is the link to the ST90 gas converted engine

http://www.bmeengine.com/html/point90.htm