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Long lasting gas powered Sailplane

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Long lasting gas powered Sailplane

Old 01-20-2008, 02:29 PM
  #26  
Rcpilot
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Default RE: Long lasting gas powered Sailplane


ORIGINAL: wws2010

Now what airframe should I use with this rewired motor and will it be able to carry the payload I need it to? Also is that 3 hours of mixed flying or full throttle moving. I also kind of need it to have a very long range.
The airframe is up to you.

Instead of asking lots of vague questions and being frustrated with the answers you're getting--start reading. Go to rccrawler and read the articles on rewinding motors. I don't know if you're going to need a 180 or a 480 size motor. I don't know if you need to wind it to 10 turns or 97 turns. That depends on what airframe you have--what the weight is--how long you want to fly it--what battery voltage you want to work with--and a hundred other variables.

The point I was trying to make is that if you want something reliable that will fly for a long time--then forget about the glow engines and fuel tanks. Use electric.

What you do with that suggestion is up to you. I've already given you plenty of information. You should be reading up on how to rewind motors. You should be investigating gliders with low wing loading and fuselages that are wide enough to carry your camera equipment.
Old 01-20-2008, 02:52 PM
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Default RE: Long lasting gas powered Sailplane

I have to agree that this has come around full circle and you're basically asking us to design the model and systems for you. It's also way beyond the scope of the glider section so I have moved it over here to the UAV forum.

Best of luck with the project but it seems like you have a lot to learn before you even figure out the basics for such a project. I'd suggest you back off and start with a more simple goal or perhaps only study one phase of the project like the stability and guidance system for such a project.

If you're set on doing the whole airplane and you want to make it electric then search for some of the electric model performance calculators that describe how much power you need to fly in various modes. At a start you'll need that to pick your payload and then work up from there. There's a lot of experience and aerodynamics knowledge needed for such an undertaking if this is all new to you. It's just not something you can ask for on forums like this since it would require us to type a book for you.

Instead of complicating the project with long range and distance why not stick with a simple takeoff, out and back scenario that can be handled with only about 5 minutes of flying time. The challenges are the same for the model and guidance systems but you avoid the whole duration thing. If I know by teachers I know that they appreciate a really good job on a simpler goal than a poor sketchy job on a really big goal that can't be adequitely supported in a short frame of time. The KISS principle will aid you. Go for a really deep and well supported effort on only one or two aspects rather than complicating the issue with the full meal deal.
Old 01-21-2008, 12:55 PM
  #28  
wws2010
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Default RE: Long lasting gas powered Sailplane

this is not even close to my first model and it is to carry two small wireless cameras as stated early and i want something that will fly for a long time and get a long range.
Old 01-21-2008, 09:13 PM
  #29  
wws2010
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Default RE: Long lasting gas powered Sailplane

oh this is far from my first model and it was clear that im gonna use this for operating cameras over an area for a long time
Old 10-12-2008, 03:07 PM
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Default RE: Long lasting gas powered Sailplane

In theory, one could use an electric powered plane with a generator, and fly infinately. This is something I will test on my predator I'm building. One plane(the first one) will have a 50cc gaser(better to have enough at lower rpms than not) then I will have another plane out of the mold right away to electrify. There are companies making generators for electric powered heli's, and I will addapt one to mine. It will power the motor batteries, as well as the FPV gear, and lighting system... Good luck on your search for the perfect platform.

P.S. My plane is on the scratch building forum under-predator b uav build 1/5 scale if enterested. I want to Fpv as well as autonomous one day so this is my perfect solution for me.
Old 10-15-2008, 10:43 PM
  #31  
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Default RE: Long lasting gas powered Sailplane

Are you saying with an electric airplane you could hook a generator in line to recharge the batteries in flight and fly forever? Really?
Old 10-16-2008, 11:17 AM
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dixielandsbigal
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Default RE: Long lasting gas powered Sailplane

Lownverted, No. That is scientifically impossible. The laws of thermodynamics are clear that energy cannot be created or nor destroyed, but it does transfer into heat.
Old 10-16-2008, 11:21 PM
  #33  
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Default RE: Long lasting gas powered Sailplane

Thanks Dixie.......I get it.......I was just seeing if that was what he really meant
Old 10-17-2008, 11:50 AM
  #34  
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Default RE: Long lasting gas powered Sailplane

Yes this is in fact what I meant. The reason the generators were madei.e. adapted to do this job what to lengthen the time inwhich one could fly theier electric heli's. It is an electric motor like the motor powering the rotors. It is turned by a gear which rotates as the rotor rotates, and the wiring hardware that comes with it regulates the power it makes at speed. The amount of power produced allows the heli to fly without the battery pack on the heli if wanted. They did it to prove the function. The power of the genorator produces enough to power the motors for the heli, charge the batteries, and several ports for lighting or what have you... yes this is real... There have been several companies that have made them for gasers too, but the bigger the motor the higher the cost. Have a guy working on a generator for a G-26 right now, and soon with have one for my gaser plane.... Hope this clears things up... it's real and has been around for a while.. (I hate having to charge batteries..) But yes the trade off to a constant running electric motor would be heat...

END
Old 10-17-2008, 11:59 AM
  #35  
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Default RE: Long lasting gas powered Sailplane

http://www.sullivanproducts.com/GenesysMainFrame.htm this is for gasers http://mysite.verizon.net/vze49gsg/ this one for electric heli.....

contacted the heli one myself. He can custom make one for gasers too.. Now ,any more questions ?
Old 10-17-2008, 07:46 PM
  #36  
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Default RE: Long lasting gas powered Sailplane

So what you are really talking about in fact is a gas (glow or heavy fuel) engine powered system, fitted with a generator that can recharge the onboard batteries of the avionics. This is standard practice for UAV's.

The link you provided for the electric system still uses a gas engine for power. This will not let you fly an electric powered aircraft forever. You may be able to extend run time slightly, sort of like regenerative braking on a hybrid car, unless of course you want to ignore the laws of physics. There is no way to get free energy in a closed loop system. Thats called perpetual motion, and it dosen't exist.
Old 10-18-2008, 06:16 AM
  #37  
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Default RE: Long lasting gas powered Sailplane

ORIGINAL: FLYBABY6

http://www.sullivanproducts.com/GenesysMainFrame.htm this is for gasers http://mysite.verizon.net/vze49gsg/ this one for electric heli.....

contacted the heli one myself. He can custom make one for gasers too.. Now ,any more questions ?
This is confusing. The heli shown is a gasoline-powered machine, as evidenced by the Tygon fuel line and the 2-stroke gasoline muffler.

As Lownverted has indicated, there is no such thing as an onboard generator for an electric-powered airplane to recharge the main (motor) batteries. If that is the goal, forget it, it ain't happenin'.

If the goal (with an electric-powered airplane) is to recharge the receiver/camera/downlink batteries, forget that as well. The complexity and weight of the generator will be more than offset by using bigger batteries.

So, forget the generator idea altogether.

You wanna stay up a long time? Get an 8-foot Telemaster, put a Zenoah G-20 (with magneto ignition, if you can find one) on it, a 32-oz gas tank, and use a couple of 3200mah 2s lipo batteries with regulators to run the Rx and all the onboard goodies. Float around for a couple hours minimum with the throttle a bit above idle. I am working on just such an airplane now, with a G-20 EI, with a 2850 mah ignition battery.

I already have a 6-foot telemaster (my first UAV project) with UNAV PicoPilot, camera/video downlink. Using two 3700 mah 3s lipos in parallel for main power, I can stay aloft for 20-25 minutes at about 1/3 throttle, which ain't half bad for an electric airplane. I downlink video and record on a laptop computer.

My suggestion is to start with a smaller project to learn how to do systems integration. Sounds simple enough to get an autopilot to work with your airplane. Until you actually try it.[>:]

Bob
Old 10-20-2008, 09:39 AM
  #38  
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Default RE: Long lasting gas powered Sailplane

well.... SEEMS I STAND CORRECTED. COULD HAVE SWORN THAT THE HELI WAS ELECTRIC.. it's not. And it seems that it's "impossible" to get 1 to 1 with an electric generator to electric power with a piggy-back system.... But I have a hard time leaving things alone, want to find a solution to it myself. But sorry I bothered all with my posts on here, was trying to help. have a nice day.
Old 10-20-2008, 10:54 AM
  #39  
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Default RE: Long lasting gas powered Sailplane

The Sullivan systems work quite well. What are you powering your UAV with? Your only duration limit will be fuel capacity. I've seen the Rascal 110 converted to a UAV and it seems to work pretty well too.
Old 10-20-2008, 12:07 PM
  #40  
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Default RE: Long lasting gas powered Sailplane

don't want to clutter up this post here with my stuff, but the first one out of the mold will have a 50cc.
Old 10-20-2008, 02:58 PM
  #41  
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Default RE: Long lasting gas powered Sailplane

How bout some pics of your progress!!
Old 10-21-2008, 04:47 PM
  #42  
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Default RE: Long lasting gas powered Sailplane

I have my own post here on rcuniverse under scratch building forum. it's the 1/5 scale predator b build.
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