Discussion Dynaflite Butterfly or similar airframe as platform for UAV

[ColbySTS]

I am College student working on an aerial mapping and imaging project of my Campus. We plan to use a Attopilot, a point a shoot and a glider to do 2 hour flights over our campus and create a map of our campus using GIS software. After searching the internet for hours for a potential airframes i stumbled across some discussion of the Dynaflite Butterfly. Its slow flying, very stable and incredibly efficient. The only problem is that it comes as a kit, and we want to spend our time calibrating and testing our camera and autopilot as apposed to building 2-3 Butterflys in our basement. Does any one have any suggestions for an ARF with similar dimensions and flight performance? One idea i had was to use a fuselage from a .40 or smaller trainer and buy some spare glider wings and convert the fuselage to work worth a much larger wing.

We plan on mounting the camera internally so we need a fuselage with width of around 4 inches, aerodynamics to a glider and a flight duration of 2-3 hours using a brushless outrunner and multiple Lipos, 7000 MaH.

Does any one have any recommendations?

[kbosak]

If you would accepts payloads up to 300g for camera and 15min flights with 5min fuel reserve, EasyUAV would do. Sold tuned and flight tested, focused on lightweight semi-pro photojob.

http://www.vimeo.com/5832423

http://www.aerialrobotics.eu/easyuav...-manual-en.pdf

Extensive autopilot manuals also available.
http://www.rc-cam.com/forum/index.php?showtopic=3278
3 weeks leadtime, 1199EUR+shipment and taxes, flies out of the box.

[space 1]

http://www.rcgroups.com/forums/showthread.php?t=1117083 I GESS I COULD BUILD ONE FOR YOU IF THE PRICE IS RIGHT

[Gary Mortimer]

How big is your Campus?? I'm not sure you are allowed to fly for more than 30 minutes autonomously in the USA without a COA.

Any bigger powered wing will work for vertical shots with an Atto, I have integrated an Atto into three different wings and the setup file worked everytime out the box.

Unless you have a huge area to record it won't take more than 40 minutes!

[brakar]

ColbySTS, I think we are quite a lot of people here at RCGroups who are trying to accomplish the same thing as you are trying to do. Possibly, there might also be a few who have allready accomplished the task, even if I have not yet spotted anyone who have told much about it. A few hints for the road:
- Teach yourself the regulations concerning UAV operations, (patrickegan here at RCG is probably one to ask),
- see if you can reduse your requirements for weight and flight-time, (life will be much easyer and it will save you time, money and effort),
- look for an IMU based autopilot, I think most important with regard to vertical photoshooting, they provide more accurate orientation datas. There are currently quite a few present. From the top of my head, among others: MicroPilot, Kestrel, SLUGS(?), FlexiPilot (I have one) and PicoPilot. Several others, at least: Attopilot 3.0 and Ardupilot Pro, are in the pipeline. (AttoPilot 3.0 are coming soon I believe).
- If you are not allready a good rc-pilot, you might be best off with a foamie airframe. The EasyStar is probably the prime choice for beginners - and for most people dealing with UAVs here at RCG, even if it has its limitations when it comes to payload, about 450 grams including batteries.

I wish you luck with your project, and hope you will post here about your progress.

Regards,

brakar

[dmgoedde]

The Atto v1.8 is not really intended for motor gliders, or I should say ones that are rudder as the onyl steering method. It's intended for planes with ailerons or elevons. This is because the thermopile-based autopilot has only a vague and laggy idea of yaw rate from GPS. This is not a great system to control a rudder airplane with.

Regarding the advice of choosing and IMU autopilot, all I can say is Atto v1.8 is about 1/3 to 1/10th the cost of the IMU systems, and the pitch and roll is constantly trimmed against standards so that it is fairly accurate. There are also the ability to trigger photos at user-defined distance intervals and even have the motor shut off right before a photo if you want (to eliminate motor vibration) while holding a flat level glide. And, there is significant data logging pertaining to each photo. Oh yeah, and Atto v1.8 ability to hold a line has been observed by many individuals and commented as remarkable.

[jglenn]

Colby: Look up the TeleMaster. It comes in various sizes, conventional airplane layout, lots of room, easy flying, good old balsa wood! To get 2 hours
in the air you will need a pretty big battery, but keep the weight down and the power needs will be minimized. Use the ailerons and the Atto should be happy.

[Mecha]

I second jglenn on the Telemaster, get the plane to run on 8s-12s with 5A-8A draw and you are in business.

[airmcn_3]

Unless you plan on flying in very low winds don’t get a telemaster. It’s a giant kite with a lumber yard worth of wood.

You should look at purpose built aircraft.

[jglenn]

You can adjust the wing loading. I find that heavy planes with a lot of power
can punch thru the wind. When I launch into a strong wind, the plane is like it is on an elevator, stunning climb rates. Just load about 5 2200 maH batts on
it! And a big ass motor. The flying balsa yard will do just fine, as you know, wood...


is more efficient for structures than foam, none of the wimpy weakness.

[airmcn_3]

Originally Posted by jglenn

You can adjust the wing loading. I find that heavy planes with a lot of power
can punch thru the wind. When I launch into a strong wind, the plane is like it is on an elevator, stunning climb rates. Just load about 5 2200 maH batts on
it! And a big ass motor. The flying balsa yard will do just fine, as you know, wood...


is more efficient for structures than foam, none of the wimpy weakness.

Heavy wing loading equates to fast landings and nasty stalls in lower wind conditions, finding a motor combination to fly that heavy bird efficiently will not be an easy task. Chances are you will be over weight for a lot of countries with UAS airframe limitations. Nitro or Gas is the way to go if you want any type of efficiency for a bird this size and weight. The facts are simple, take a fuse with a cross section the size of this bird and try and hold it out your car window at 40mph at any angle........ It’s a freaking barn wall.

This bird is good for what it was designed for. Lazy RC flying with no care for efficiency.

Foam can be plenty strong especially when it is a core of a fiber glassed wing.

[jglenn]

The guy wants to fly 2 hours, and does not need a hard to fly plane, like a flying wing. A conventional layout, like a trainer, should be efficient. He has
to stay away from strong winds. I guess the wing loading should be light for a long flight time. Fiberglass over foam is super, as long as it is not an airbus
rudder. Held on by 2 or 3 pins. Scary, I saw the pic.

[airmcn_3]

Originally Posted by jglenn

Fiberglass over foam is super, as long as it is not an airbus
rudder. Held on by 2 or 3 pins. Scary, I saw the pic.

LOL. When things go bad with composites they usually go very bad.....

[jglenn]

I am an electrical head, was amused to read a tech analysis of a carbon fiber
airliner fuselage, seems it does not have a characteristic that everyone has
gotten used to:

The Faraday Cage.

Sensitive electronics and steering junk is protected from lightning with aluminum.

But carbon fiber does not conduct as well, so they embed tiny wires in it to conduct the millions of amps. No inherent shielding action.

And they wonder why they slam into the ocean during storms. Blame the
pitot tube. Well, it is true the computer is mainly looking at airspeed, everything is based on it, there is no backup. Some people are screaming for
an angle of attack sensor. Heck if I know.

[jtprouty]

Flying wings aren't that difficult to fly, especially if you have Atto assisting and pick the right airframe. Flying in over 20 MPH winds with great efficiency is easy with the proper airframe.

Jimmy