Hello everyone, I'm a researcher at Taylor University and was hoping for some advice from RC airplane experts about the best choice for a plane to convert into an autonomous plane. We believe we want something in a glow engine trainer, something stable and easy to fly, with as few moving control surfaces as possible. We've looked into electric planes like this
are simple and stable, but they don't seem to have the space or power to accommodate additional electronics to control the plane. Essentially we want that plane, but heavier duty and gas powered for the range and space and horse power. It's a funded project so cost is not a big concern. If anyone knows of someone who manufacturers such a plane or has run accross a similar project I'd be very interested in hearing about it. Thanks in advance! Nathaniel Colson
On 24 Oct 2006 16:57:48 -0700, "NathanielC" wrote in :
Here's the top of the heap:
They flew one of their planes across the Atlantic with a 1.2 ci motor. I'm not sure whether it was gasoline or alcohol-based fuel.
A ready-to-fly aerosonde is probably in the $25,000 range or thereabouts. (I'm in the category of those who are too poor to ask the price.)
At the other end of the spectrum, you've got Maynard Hill's team, who sent a 5 kg (WET!) aircraft across the Atlantic:
He used a highly reworked OS .61 four-stroke on naptha-based fuel.
A huge amount of work has been done on aerial robotics in any number of competitions:
If I was on a decent budget, I'd go with Bruce Tharpe's Super Flying King:
But you have to be willing to build the plane. I'd think that $1500 would give you a very nice platform with plenty of payload capacity.
There are lots of excellent .60 ci (10 cc) planes that are cheap and serviceable. My buddy loves the Hobbico Hobbistar:
You can buy this in an Almost Ready to Fly condition. I'm sure it could carry a decent payload moderately safely (3-4 lb), but the fuselage is narrow. You might have to provide a larger bay under the wing for your onboard equipment.
You need a good RC pilot to help you trim your plane and make sure that it can fly before you commit it to the care of your avionics. You can find AMA clubs in your neighborhood, and they should be able to help you find someone who would help you learn to fly and/or act as your safety pilot.
You should expect to be vetted by the FAA and Homeland Security as well. If I were you, I'd take proactive steps to make sure that you don't violate any of their rules. Some of them probably saw the Man from Uncle show in which an RC plane was used as a weapon.
Commercial UAV Autopilot GPS system:
A bunch of hobbyist UAV links:
A few years ago, I came across a wonderful page on a UAV team flying in Canada. I've lost the link, but it sure seemed like they were having fun.
Good luck with your project.
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While it's by no means "that plane", have you considered a Telemaster. Comes in both a 6' and 8' wingspan version, as well as a "mini" version. The two larger are really designed for glow power, but can be electrified.
The telemaster looks like an old-fashioned high-wing aircraft. It is very stable, will fly quite slowly, and the fuselage has LOTS of room for any additional equipment you may want. It will also carry quite a bit of extra weight. It can be built with or without flaps, and normally is built with ailerons, elevator, and rudder. Looks old-fashioned, but is stable and large enough to carry anything you would need for an autonomous plane.
Two good replys already from Marty and Bob - you're on a roll! I think an essential spec to narrow down the field of airframe candidates is the estimated weight of your avionics/payload package. The 'toy' you looked at is marginal with just the battery aboard to power it, but that certainly doesn't rule out electric power. What Bob and Marty suggested can both be powered with electric motors too, readily available but much more capable in terms of power density and efficiency. Give us a guesstimate at weight and volume of what you want to loft and for how long, and I'm sure the denizens of this group can give you some useful pointers.
Taylor? That's in Indiana, so why not go to Muncie and talk with the AMA museum folks?
They had Maynard Hill's "Spirit of Butts Farm" displayed there for some time, and will likely be able to dig up some good information for you.
Regarding Marty's superb comments, I'll add that Bruce Tharpe is aquainted with the chief engineer on the Aerosonde project, and I'm guessing that he knows a thing or three about making the Flying King autonomous! By all means contact him.
The Senior Telemater is a fine plane for reasonable cost and can carry a substantial load. It can (according to the originial German instructions) be flown with Rudder only (elevator and motor, of course) by fixing the ailerons in place and increasing the dihedral from 2 1/2 inches to 5 inches...and a word to the wise...be sure the dihedral braces are beefed up... This plane can be flown wth any .40 to .61 cu. in. glow engine...anything more is beyond the riginal specifications.. Frank Schwartz
"Chang Industry is also working on a larger and more sophisticated version of the plane. These eight-foot wide planes would have a rigid wing, and a camera with the ability to pan, tilt and zoom and to provide night vision capabilities.
More important, these advanced planes would have autonomous flight capability, meaning they would not have to be guided constantly by someone with a remote control. Using a Global Positioning System receiver and programmed maps, Dr. Chang said, the plane could be programmed to fly to a target and circle it before returning. This larger plane would cost approximately three times the Kite Plane, about $15,000.
Chang Industry will have to compete with autonomous U.A.V.'s already on the market. L-3 BAI Aerosystems, based in Easton, Md., makes a 44-inch-wide plane called the Evolution, which sells for $25,000 and flies on its own with live video feeds that can be transmitted up to 12.5 kilometers. The Evolution, which can be transported in pieces in a backpack, is designed to collapse into its component pieces upon impact, leaving open the chance for reassembly.
Jay Willmott, the company's executive vice president, said that the United States Marshals Service uses the Evolution plane, and that the Maryland Port Authority is also interested in acquiring a small fleet.
One obstacle to more widespread use of U.A.V.'s is the lack of Federal Aviation Administration regulations for their use.
Paul Takemoto, a spokesman for the F.A.A., said that U.A.V.'s must be evaluated on a case-by-case basis, and that using them in an urban area required F.A.A. approval through a one-year "certificate of authorization" for a particular plane in a specific area. A rural or remote area, such as a testing zone, would not have the same restrictions, Mr. Takemoto said.
However, the F.A.A. is currently drafting sweeping regulations on the use of U.A.V.'s. The agency hopes to have the regulations completed by September."
Thanks for the replies and links guys! Sorry if I was vague on a few points. Here are some specific requirements for what we're looking for, in order of importance:
- 2 or fewer moving control surfaces (so a rudder and perhaps elevators, but no ailerons or flaps)
- Enough power and lift to handle a couple extra pounds of electronics, about the size and weight of two or three decks of playing cards (and shaped however we want).
- Durable enough to withstand rough landings (microcomputers aren't notorious for their landing finesse, so balsa wood is less than optimal)
- Inexpensive enough that we could crash one and not be too sad (preferably < $500)
- 30 - 60 minutes of flight time
We're emphasizing minimal moving control surfaces to make the plane as easy to control as possible, because it would take a huge amount of effort to make our microcomputer smart enough to control a 7-channel plane, especially when all we're interested in doing is flying straight lines between waypoints. We're pretty set on a bent wingtip design with no flaps or ailerons, and possibly no elevator or rudder either like the v-tail design. We have a fairly good idea what we want in a plane, we're just not sure where to look to find one with the cargo and range requirements.
Electric vs. gas-powered is still up in the air. I think if electric can supply the range and lift it would be preferable simply because it's cleaner and quieter, and because I get the idea that fewer things can go wrong with a motor as compared to an engine. Perhaps you guys could shed some light on that decision too?
One of the most popular current EP aircraft for camera operations and UAV experiments is the Multiplex EasyStar - almost unbreakable yet very easy to fly and carries a huge payload for its size: see video and other reference at
On 24 Oct 2006 22:19:32 -0700, "NathanielC" wrote in :
It all depends on how good your GPS is. Turning off the engine at the right time and floating into a large field for a landing is not wholly inconceivable.
The more crash-proof you make an airframe, the heavier it gets. Then you need more power to get it off the ground and keep it in the air, which means more fuel, which means more weight, which means more momentum to cause damage in a takeoff crash, which means you need a stronger airframe, etc.
$500 of damage is probably doable, depending on how bad the crash is. Many parts survive that can be re-used in the next plane.
$500 for all-up expenses is a very tight budget.
Not impossible with a large gas tank and a fuel-efficient engine, but you need to calculate the weight of the fuel and the change in CG caused by it burning off during the flight. The change in distribution of the fuel in the tank is also tricky, because unpumped engines have difficulty drawing fuel very far.
You might look at powered gliders or other designs with high-aspect wing ratios if speed over the terrain is not an issue.
Which reminds me--there is a Canadian company producing commercial GPS systems to do photo-reconnaissance of farms. I don't have time to search for the link now. I saw the link in rec.aviation.piloting in a thread about the dangers of piloted planes sharing airspace with unpiloted planes.
Study Maynard's design. I think he used minimal controls in order to reduce induced drag (something like aileron and one elevator just on half of the horizontal stab).
I have flown lots of combat models with just aileron and elevator. The Gremlin, a flying wing, uses ailevators (two servos mixed to produce aileron and elevator functions).
You're not going to get batteries that are crashworthy and can keep your payload in the air for 30-60 minutes for anywhere near $500. That kind of battery technology will cost you around $3000 just to get into the ball game (chargers & extra sets of batteries to allow more than one flight a day). If you crash the best batteries (lithium ion), they may blow up and set everything on fire.
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To handle the extra weight requirement, you will need either a glow-powered model, or a larger electric, or electric-converted glow model.
$500 is going to be a very tight budget, especially since I assume you will need regular radio gear to control take-off and landing (although this CAN be controlled with some of the more elaborate and expensive GPS-based units)
You can do this with a glow-powered aircraft for considerably less than an electric. With a glow aircraft, you will need to watch both wet and dry CG closely. I use a Telemaster for semi-autonomous flight, mainly used for airborne video using an rf downlink. Some of its missions are well over an hour. To solve the shifting CG problem, I built a partially wet-wing with the fuel on the CG, which drains to a snall header tank (and also use a perry pump to stabilize the fuel pressure). To get that sort of flight time in an electric that is capable of carrying an extra pound or two will require batteries that will by themseslves be WAY over your $500 budget. My semi-autonomous set-up simply uses an "autopilot" (basically a device that keeps the plane level in 2 axes, as well as a gyro to control heading. It still requires a regular RC transmitter and receiver for take-off and landing, as well for any course changes. You can, however, allow it to flly outside of radio range, and then use the passenger vehicle of your choosing to get back into range to regain direct control. My video transmitter/receiver setup actually has more range than my RC gear (and the transmitter/camera is powered by an on-board generator (Genesys -- Sullivan).
Your microprocessor is still going to have to handle quite a bit of data, even if you minimize the number of control surfaces. Assuming a V-tail design, the processor will still have to handle rudder AND elevator inputs, and will also have to mix these inputs to get the desired outputs to the control surfaces. There will also be the question of some form of altitude control using signals from your GPS through the microprocessor (or barometric, etc.), and you will likely also need some form of engine channel, unless you plan on the entire flight operating at a single throttle setting (not real practical during take-off and landing).
Glow-fueled will be cheaper, but you can perform this function with electrics as well. Be aware that the electric motor needed to fly a model large enough to handle your electronic bay and "a couple" of extra pounds will likely cost as much or more than a comparable glow engine, and batteries that will allow for flights this long will be much more expensive -- conceivably as expensive as the entire model and engine along with some of your electronics. Just the batteries to handle an electric model of this size for that length of time may weigh as much as 30 oz.
There are a couple of companies making more-or-less turn-key solutions for what you are seeking to do in terms of the gps and control electronics. I don't have the links readily at hand, but will see if I can't find them tonight.
And don't forget the cost of insurance (AMA won't work) and legal fees, which you will surely have once someone catches wind of what you are doing.
Unlicensed/approved autonomous aircraft are not considered to be on the government friendly list these days. One could probably argue that they are not recreational models and therefore are not permitted to share our airspace without special exception (where the lawyer enters the picture BEFORE an incident).
Just because you can do a thing, is no reason to assume that you should do a thing.
Great question Mr. Davis, essentially what we're doing with the plane is twofold. First, we are very active in small satellite research here at Taylor
and we hope that the plane will eventually serve as a testbed for satellite components and balloonsat components before they are launched (which costs a whole lot more than charging airplane batteries). Secondly, the project serves to bring underclassmen into engaging and challenging projects early on, which is critically important at an undergrad school where we don't have grad students around for an additional four years to further develop projects. We have several other visions for an autonomous plane, such as wirelessly collecting data samples from water testing stations for our ENS department, but those are the primary goals of the project.
Ok, update: I've measured the exact weight of the components of our electric control system, and the guestimate I posted earlier was pretty high. I was thinking of the battery pack and radio and microcontroller development board (as well as a sonar rangefinder we don't need if we can glide into a landing), but those won't be part of the "extra" payload. Just the PCB with the microcontroller, GPS unit, and some other odd and ends will be under 6 ounces, so it's a little more conceivable that they will fit into a plane like the EasyStar
In light of this relaxed payload requirement, the remaining setbacks to electric that I see are flight time and cost. Average flight times seem to be in the 10-20 minute range, although we're hoping that by keeping fancy maneuvers and changes in altitude to a minimum we can stretch that out past half an hour. I have very little flying experience, so I'm not sure how flying style impacts battery/fuel consumption. What are your guys' thoughts?
A final note is that this is primarily a computer engineering project, so we're trying to keep complex modification of the airplane body to a minimum. Ideally we'll be able to buy a plane and use it out of the box.