Building a full size drone from a donor GA plane

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sixpacker

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Sixpacker
Just a theoretical question :D

How would one go about doing this? I was thinking the best way would be to find a way to customize an existing autopilot unit. It should be possible with an android GPS device to control and dynamically sequence the autopilot. For sh*ts and giggles let's say it is a three axis autopilot. The issues that initially occur to me are how to remotely communicate (it would probably need a satellite based means of communication) and also throttle control (mixture too but less so you could probably just run it full rich).

Not planning on doing this of course was just wondering if any of you have insight or ideas on ways this could be done.

Oh, and Merry XMas everyone.
 
The thing missing is auto throttle, so you would need a servo and channel to work that as well. It's not difficult, it could likely be rigged using some commercial software and use altitude change commands to operate the throttle. Mixture is unnecessary, it can be automated with an android device as some planes already have.
 
The flight controller for my little drone could very easily be interfaced into a full size aircraft. Interface the low voltage servo outputs to a higher powered servo to operate the controls, or to existing autopilot servos. It will take control inputs from a handheld remote, telemetry datalink, or preprogrammed course. They can even auto takeoff and land.
 
Pedals2Paddles said:
The flight controller for my little drone could very easily be interfaced into a full size aircraft. Interface the low voltage servo outputs to a higher powered servo to operate the controls, or to existing autopilot servos. It will take control inputs from a handheld remote, telemetry datalink, or preprogrammed course. They can even auto takeoff and land.
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Probably a simple PLC would suffice for the interface.
 
This begs the question: would there be anything illegal about doing this? Is there a specific weight and size restriction on R/C aircraft for hobby use? Would a Cessna 172 with no people on board still require an airworthiness certificate?

What rule would apply: 500 ft maximum altitude or 1000 ft vertical and 2000 ft horizontal from highest object?
 
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All I'm saying is: what are the specific regulations that determine you can't? I've seen video's of that R/C B-52 and it ain't (wasn't) much smaller than a Sonex. It even formed a small mushroom cloud when it crashed.

https://www.youtube.com/watch?v=Dw0javaaxfY
 
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Silvaire said:
This begs the question: would there be anything illegal about doing this? Is there a specific weight and size restriction on R/C aircraft for hobby use? Would a Cessna 172 with no people on board still require an airworthiness certificate?

What rule would apply: 500 ft maximum altitude or 1000 ft vertical and 2000 ft horizontal from highest object?
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Others make fun of the question but don't provide any data on it. It's an interesting question, especially with regards to requiring an airworthiness certificate.

Intended use will play a factor, if it is going to generate revenue, you will definitely have issues, as I believe there will be allowable airspace issues. However if you have a 1000 acre ranch and if you do it with a Pawnee rather than a 172, and set it up with a full Satloc system including flow control, and an autopilot to fertilize your fields and the aircraft stays below 200' and over your property, the situation becomes less clear as to whether they have anything to say about it.
 
Let's put it this way.

We have "full size" drones at work. One (Ikhana) is a Predator, and the other is a Global Hawk. Both are assigned to the Airborne [Earth] Science Program.

We have been slowly transitioning their tasks to the Gulfstream III and other manned jets because they are cheaper to run.
 
MAKG1 said:
Let's put it this way.

We have "full size" drones at work. One (Ikhana) is a Predator, and the other is a Global Hawk. Both are assigned to the Airborne [Earth] Science Program.

We have been slowly transitioning their tasks to the Gulfstream III and other manned jets because they are cheaper to run.
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The word "drone" is kind of broad these days. I suspect that what the OP meant was a quad copter style drone the size of a 172. My opinion on this idea is it's just not practical at this time. Batteries just don't have the energy density to employ electric motors and using gasoline engines is just a nightmare in the making. The larger question is, why would anybody want a "full size" drone?
 
Dav8or said:
The word "drone" is kind of broad these days. I suspect that what the OP meant was a quad copter style drone the size of a 172. My opinion on this idea is it's just not practical at this time. Batteries just don't have the energy density to employ electric motors and using gasoline engines is just a nightmare in the making. The larger question is, why would anybody want a "full size" drone?
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Oh not at all what I meant.

I am talking about taking something like a 172 and turning it into a drone. I would think that if one is already set up with an autopilot it should not be impossible to set it up so that the servos are being controlled remotely. I don't know of any 172 with a three axis AP but the same process could be used to control the rudder. As for throttle, there are probably better ways to do it but I could definitely set up a stage plus ballscrew and servo motor with a couple of limit switches and a motion board to set that remotely. There is probably a more elegant solution. The issue gets down with how to communicate. Line of sight should be easy and probably the only legal way to do this.

Just a thought experiment. It seems very doable to me.

Legal? I don't know. Is there a size limit on drones today?
 
Silvaire said:
This begs the question: would there be anything illegal about doing this? Is there a specific weight and size restriction on R/C aircraft for hobby use? Would a Cessna 172 with no people on board still require an airworthiness certificate?

What rule would apply: 500 ft maximum altitude or 1000 ft vertical and 2000 ft horizontal from highest object?
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There are certian size and weight restrictions on RC aircraft. (of the hobby variety) I forget the exact figures but <100 pounds comes to mind.
Well; 55 pounds is <100 pounds. :yes:
 
To answer the origional question by the OP. Yes, it's very doable. They already exist in sizes way bigger than a 172.
 
Brad Z said:
A Cessna 172 is just a bit heavier than 55lbs, so you'll have a hard time convincing the FAA its a model airplane.

http://www.faa.gov/uas/publications/media/model_aircraft_spec_rule.pdf

Better to try to get authorization from the FAA as a proper UAS...which isn't going to be happening very quickly.
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That makes perfect sense but what you have linked us to is an interpretation of the FAA Modernization and Reform Act of 2012 which apparently states that if a "model" aircraft meets specific statutory requirements, one of which is a maximum weight of 55 lbs, then the FAA is prohibited from "promulgating any rule or regulation" regarding it.

The only real limits I see (as things are currently written) are that it must remain below 400 feet altitude and in line of sight. Being that a 172 would be a humongous "model aircraft" it could get pretty far away and you'd still be able to see it.

Sounds crazy I know but I'm just looking to see if there is anything that would stop someone from doing this if they had a hankering to? I don't see any technological obstacle, it could certainly be accomplished quite easily without inventing anything new.
 
Doesn't the Air Force have lots of full-size planes that have been converted to target drones? It's certainly feasible to do the same with a 172, and would probably be trivial if you already have a three-axis autopilot, since you just need a means of remotely controlling the autopilot.
 
Silvaire said:
That makes perfect sense but what you have linked us to is an interpretation of the FAA Modernization and Reform Act of 2012 which apparently states that if a "model" aircraft meets specific statutory requirements, one of which is a maximum weight of 55 lbs, then the FAA is prohibited from "promulgating any rule or regulation" regarding it.

The only real limits I see (as things are currently written) are that it must remain below 400 feet altitude and in line of sight. Being that a 172 would be a humongous "model aircraft" it could get pretty far away and you'd still be able to see it.

Sounds crazy I know but I'm just looking to see if there is anything that would stop someone from doing this if they had a hankering to? I don't see any technological obstacle, it could certainly be accomplished quite easily without inventing anything new.
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That's all I can see as well. My buddy had an RC B-29 he built that that was bigger than my Midget Mustang. The only limitations I am aware of is 400' and line of sight. Of course given these limitations building a "full scale" drone of a GA plane would have dubious value. The only way I see it would be useful is in Ag work.

I can see the day when preprogrammed quad copters are going to take over pipe and power line inspection for next to nothing. For the cost of one run a week for a quarter, you could buy a fleet of IP camera quad copters and stick them every 5 miles, you can run them once or twice a day for pennies a day. If you have a bad pressure reading somewhere, you have an asset looking at that sector in minutes.
 
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Lindberg said:
Doesn't the Air Force have lots of full-size planes that have been converted to target drones? It's certainly feasible to do the same with a 172, and would probably be trivial if you already have a three-axis autopilot, since you just need a means of remotely controlling the autopilot.
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Joe Kennedy Jr. died in one during WWII, a B-24 I believe. Since they were loaded with a lot of explosive, they made human crews get them to the south coast and bail out just before they go feet wet.

They used to use P-51s as target drones for training before and during Vietnam. :sad:
 
Silvaire said:
That makes perfect sense but what you have linked us to is an interpretation of the FAA Modernization and Reform Act of 2012 which apparently states that if a "model" aircraft meets specific statutory requirements, one of which is a maximum weight of 55 lbs, then the FAA is prohibited from "promulgating any rule or regulation" regarding it.

The only real limits I see (as things are currently written) are that it must remain below 400 feet altitude and in line of sight. Being that a 172 would be a humongous "model aircraft" it could get pretty far away and you'd still be able to see it.

Sounds crazy I know but I'm just looking to see if there is anything that would stop someone from doing this if they had a hankering to? I don't see any technological obstacle, it could certainly be accomplished quite easily without inventing anything new.
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Enjoy your fantasy as you please but I can assure you with 100% certainty that a remotely piloted 172 would not be considered a model airplane by the FAA. Period.
 
If you want to fly your C-172 drone you need to do what all the other civilians doing things like this are doing. Get range time at one of the approved UAV ranges in the United States.

Get specific approval for your aircraft and test plan from the FAA.

Fly your drone!
 
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Brad Z said:
Enjoy your fantasy as you please but I can assure you with 100% certainty that a remotely piloted 172 would not be considered a model airplane by the FAA. Period.
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As long as it stays <400' and within line of sight, show me a regulation the FAA has to enforce that applies.:dunno:
 
Oh gee.....it's an airplane for heaven sakes.....does it matter how it's being controlled?:goofy::rolleyes:
 
JimNtexas said:
If you want to fly your C-172 drone you need to do what all the other civilians doing things like this are doing. Get range time at one of the approved UAV ranges in the United States.

Get specific approval for your aircraft and test plan from the FAA.

Fly your drone!
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Very interesting thanks for the links.

Sounds like a fun area to get into.
 
Brad Z said:
Enjoy your fantasy as you please but I can assure you with 100% certainty that a remotely piloted 172 would not be considered a model airplane by the FAA. Period.
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That's fine and I have no fantasy about it. Just show me the regulation that says that. :dunno:
 
Silvaire said:
That's fine and I have no fantasy about it. Just show me the regulation that says that. :dunno:
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here ya go.....good luck. :D

Model Aircraft Operations Limits According to the FAA Modernization and Reform Act of 2012 as (1) the aircraft is flown strictly for hobby or recreational use; (2) the aircraft is operated in accordance with a community-based set of safety guidelines and within the programming of a nationwide community-based organization; (3) the aircraft is limited to not more than 55 pounds unless otherwise certified through a design, construction, inspection, flight test, and operational safety program administered by a community-based organization; (4) the aircraft is operated in a manner that does not interfere with and gives way to any manned aircraft; (5) when flown within 5 miles of an airport, the operator of the aircraft provides the airport operator and the airport air traffic control tower…with prior notice of the operation; and (6) the aircraft is flown within visual line sight of the operator.
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Same link we had earlier in the thread. Read the beginning of the paragraph you quoted, it says that if the "model" complies with all of those statutes then the FAA is prohibited from "promulgating any rule or regulation" regarding it. (see post #21)

You don't have to wish me luck, I have no desire to build a drone 172 and I'm not the person who started this thread. I'm just saying that I don't see any regulation on the books that would prevent a person from doing it.
 
Henning said:
As long as it stays <400' and within line of sight, show me a regulation the FAA has to enforce that applies.:dunno:
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Silvaire said:
That's fine and I have no fantasy about it. Just show me the regulation that says that. :dunno:
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Prove to the FAA that your 172 is a model aircraft. Otherwise they are responsible for regulating it under 49 U.S.C. 44704. Considering the 172 was issued a type certificate by the FAA, I think you're going to have a hard time proving your project is a model airplane.

Based on your argument, you could take that same airframe, take it apart and put it back together, and decide that you've built an airplane out of it, and it's now an amateur-built experimental.
 
Brad Z said:
Prove to the FAA that your 172 is a model aircraft...
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Why? Do people with R/C aircraft have to prove anything to the FAA? Is there a form to fill out?

Brad Z said:
..Based on your argument, you could take that same airframe, take it apart and put it back together, and decide that you've built an airplane out of it, and it's now an amateur-built experimental.
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No, not really because there are not going to be any passengers on the drone. That's why we were wondering if there might not be any requirement for an airworthiness certificate? :dunno:
 
Silvaire said:
I'm just saying that I don't see any regulation on the books that would prevent a person from doing it.
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I think it's one of those deals where there are no specific regulations covering it yet, because nobody has been dumb enough to actually do it, but if you did, the FAA would come down and tell you why you can't do it. After that, it would be your lawyers against theirs. Once that was concluded, then the real regs would be written.

Common sense says, it's a bad idea. Doing it just to test the boundaries of the written regs is an even dumber idea.
 
I'm just saying that I don't see any regulation on the books that would prevent a person from doing it.
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Part 61 and 91 are pretty clear on what is required to fly a C172 in the national airspace. Why would you think leaving the plane on autopilot somehow exempts your C172 from the same rules that the rest of us must follow?
 
JimNtexas said:
...Why would you think leaving the plane on autopilot somehow exempts your C172 from the same rules that the rest of us must follow?
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Maybe 'cause there aren't any people on it and therefore it's not the same thing at all. Granted the whole notion is silly as we have no valid reason for doing it in the first place and that's probably why there are no regulations covering it but that's all this conversation has been about - regulations and if there are any on the books that would prevent a person, however nutty you might consider it, from doing such a thing.
 
Brad Z said:
Prove to the FAA that your 172 is a model aircraft. Otherwise they are responsible for regulating it under 49 U.S.C. 44704. Considering the 172 was issued a type certificate by the FAA, I think you're going to have a hard time proving your project is a model airplane.

Based on your argument, you could take that same airframe, take it apart and put it back together, and decide that you've built an airplane out of it, and it's now an amateur-built experimental.
Click to expand...

With the correct amount of modification, that is possible.
 
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