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Long lasting gas powered Sailplane - 1/17/2008 2:52:10 AM   
wws2010


 

Posts: 94
Joined: 8/18/2007
From: SunlandCA, USA
Status: offline 		I was in the market for a super long lasting sailplane that is nitro powered. I am fine with arf but kits or plans will be prefered. I need it to carry about a half a pound or more and be able to take off and land in about 50 yards or less. Does anyone have any ideas? All imput is appreciated.


< Message edited by wws2010 -- 1/17/2008 2:53:00 AM >
       Post #: 1

RE: Long lasting gas powered Sailplane - 1/17/2008 4:32:19 AM   
OzMo



Posts: 1434
Joined: 9/2/2002
From: OZark, MO, USA
Status: offline 		Not to sure what you want here. Do you want a tough airplane that will last for years or a long duration flight. Might also make a difference what you want to carry. Use is a key factor in determining a certain plane.

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Yes dear, I did glue my hand to the airplane to keep from dropping it.

(in reply to wws2010)
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RE: Long lasting gas powered Sailplane - 1/17/2008 4:52:54 AM   
wws2010


 

Posts: 94
Joined: 8/18/2007
From: SunlandCA, USA
Status: offline 		i am sorry, a long flight time and it will be carring 2 small wireless cameras and or tons of fuel

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RE: Long lasting gas powered Sailplane - 1/17/2008 5:00:46 AM   
OzMo



Posts: 1434
Joined: 9/2/2002
From: OZark, MO, USA
Status: offline 		I thought as much I would take a look on ebay as there are several powered (gas or glow fuel) planes there now . Seach "Sailplanes" a 15 to 25 would haul a couple of those around and are fuel SIPPERS. Any ailplane over 99" might work well and all the balsa kits could be converted without much trouble. A dynaflight butterfly comes to mind.

< Message edited by OzMo -- 1/17/2008 11:44:40 PM >

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Yes dear, I did glue my hand to the airplane to keep from dropping it.

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RE: Long lasting gas powered Sailplane - 1/17/2008 5:32:49 AM   
wws2010


 

Posts: 94
Joined: 8/18/2007
From: SunlandCA, USA
Status: offline 		will that be able to land in about 50 yards and how long can I fly for on the stock fuel tank?

(in reply to OzMo)
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RE: Long lasting gas powered Sailplane - 1/17/2008 5:58:38 AM   
wws2010


 

Posts: 94
Joined: 8/18/2007
From: SunlandCA, USA
Status: offline 		are there any other models available that boast the same stats.

(in reply to wws2010)
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RE: Long lasting gas powered Sailplane - 1/17/2008 4:06:45 PM   
OzMo



Posts: 1434
Joined: 9/2/2002
From: OZark, MO, USA
Status: offline 		You may want spoilers or flaps to keep the landing short

_____________________________

Yes dear, I did glue my hand to the airplane to keep from dropping it.

(in reply to wws2010)
       Post #: 7

RE: Long lasting gas powered Sailplane - 1/17/2008 6:54:15 PM   
khelsea


 

Posts: 78
Joined: 2/7/2005
From: Detroit Lakes, MN, USA
Status: offline 		This might work. With a 52 4 stroke just above idle it will fly till I get bored. Rene Saenz " the funk works" U-2
Khelsea Lanny

Attachments
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(in reply to OzMo)
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RE: Long lasting gas powered Sailplane - 1/17/2008 9:56:56 PM   
BMatthews



Posts: 8943
Joined: 10/4/2002
From: Burnaby, BC, CANADA
Status: offline 		A 15 will be enough power to fly a 100 inch model with a reasonable payload of perhaps an extra 1.5 lbs over the weight of the glider. Engine duration will be dependent on the fuel tank size. However a .15 will have trouble running consistently with more than 4 oz of fuel. Certainly a 6 oz tank would be asking for trouble. If you need more than the 20'ish to 25'ish minutes of run time the .15 with 4oz will provide then you need to get yourself working with a larger supply tank that feeds a small "float bowl" tank up by the engine. It would literally have to have a float in it and a needle valve similar to the float bowl in the old car, motorcycle and lawmmower engines of old. The idea is that the light suction power of the .15 to .25 needs to operate with a consistent fuel level so it can suck the same amount of fuel for the whole duration of the supply. There is just no way to provide that level of consistency with more than a 4oz tank. In fact in my experience even the 4oz tank is pushing it and you'd need to set it a hair on the rich side while full.

Takeoff is no problem. A handlaunch requires no distance at all. Landings would benifit from spoilers or flaps but a typical landing "slide" for such a model would easily be less than 30 feet.

You may also want to look at something more like a stick built old timer. They come out very light, can easily carry your payloads and can easily take off in 30 to 35 feet even in calm weather and land within 50 to 60. Less if you were to use a custom wheel brake system. It would not have to BE an old timer. It just needs to be built LIKE one so a basic box and rectangular wings is fine. Just don't use much wood.


_____________________________

Bruce-
Proudly wasting balsa since 1965.

Free Flighters go that extra mile........

(in reply to khelsea)
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RE: Long lasting gas powered Sailplane - 1/18/2008 1:46:06 AM   
wws2010


 

Posts: 94
Joined: 8/18/2007
From: SunlandCA, USA
Status: offline 		ok the problem with the small 4oz fuel tank can be solved with a drip tank that drips in at the same rate being used right? Or would something like a three way valve from an old autococker(Paintball gun) work with a servo attached and have that swich over once the time is right? woud those work with any plane i decide to go with? ive looked at all the designs and they work but all other imput is good and apreciated i am looking for something different

(in reply to BMatthews)
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RE: Long lasting gas powered Sailplane - 1/18/2008 4:56:01 AM   
BMatthews



Posts: 8943
Joined: 10/4/2002
From: Burnaby, BC, CANADA
Status: offline 		The three way valve from the autocockers won't work. You forgot that they also have an exhaust vent hole in them. However if it wasn't for that then yes it could potentially work out. But you'd need room for both tanks in the nose and in close as possible proximity to the engine.

The other deal I mentioned isn't a drip tank. I was talking about a full on supply on demand float controlled shut off valve so that regardless of how fast or slow the engine demands fuel the level in the float bowl would remain constant until the supply tank over by the wing was drained dry.


But this brings up the next question. Why do you want to fly for SO long? For most of us up to around 10 to 15 minutes is plenty. With that much flying time there's lots of time to reach altitude and take pictures to your heart's content without resorting to extreme solutions.


_____________________________

Bruce-
Proudly wasting balsa since 1965.

Free Flighters go that extra mile........

(in reply to wws2010)
       Post #: 11

RE: Long lasting gas powered Sailplane - 1/18/2008 5:10:21 AM   
wws2010


 

Posts: 94
Joined: 8/18/2007
From: SunlandCA, USA
Status: offline 		no i am saying tht you route the engine in the center hole and the two fuel lines on the outer two, that would work right? The reason that i want such long flight times is that it will be a kind of uav for my senior project at school. And i really want to wow the teacher.

(in reply to BMatthews)
       Post #: 12

RE: Long lasting gas powered Sailplane - 1/18/2008 1:32:08 PM   
da Rock



Posts: 6654
Joined: 10/11/2005
From: western, NC, USA
Status: online 		Do some research for the magazine articles by Maynard Hill on the model airplanes he used to set his world records. The last one was a single flight across the Atlantic. Long enough time?

The articles cover the problems of using model airplane engines and tankage issues. His solutions were simple and clever. And his narratives explained all the over-engineered failures and why/how he wound up solving with simple.

(in reply to wws2010)
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RE: Long lasting gas powered Sailplane - 1/18/2008 10:39:51 PM   
dixielandsbigal


 

Posts: 113
Joined: 1/2/2004
From: Watertown, SD, USA
Status: offline 		try a dynaflight butterfly. the one in our clubs flies FOREVER!


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RE: Long lasting gas powered Sailplane - 1/18/2008 11:30:45 PM   
Furious Predator


 

Posts: 11
Joined: 12/30/2007
From: Kitchener, ON, CANADA
Status: offline 		i second the Butterfly by Dynaflite.

i have had one for over 4 years now. the kit goes for about $75, 99" wingspan, and is made for a .15 2 stroke. i have an OS 20 four stroke on mine. the entire setup RTF weighs about 5 pounds.

i only use a 4oz fuel tank for it, and it can run for about 20 minutes wide open, you can get 3-4 boosts from the ground up high into the thermals per tank of fuel.

it climbs just fine considering how little power the motor has.

the Butterfly is VERY VERY stable, vertually hands off flight, strong wing design, and incredibly slow landing speeds...you can almsot walk beside it.

very nice fuse construction, very durable, she can take some rough landings.

what i normally do, is use the engine to get her to about 500-600 feet, and shut down the motor...OR....let it idle till it runs out of fuel. keeping it in idle will keep it in the air if your having trouble finding thermals. but generally i find with this plane, it doesn't take a very big thermal to keep it going. i generally dont even look for them and it keeps going up. i normally land with a sore neck...which is pretty much the determining factor on how long i fly it.

now...for the downsides.

the landing gear design it comes with is garbage, your much better off leaving it alone and belly landing it. this leaves a cleaner look as well.

also...there are no spoilers. i have had a huge challenge trying to time my landings to get it roughly in the spot i want...she just doesn't want to land. its actually hard to get it on the ground. so very shortly, when i finish my electric BOT, i will be installing spoilers in the wings to assist with landings.

Check out my Run Ryder gallery for pics.
http://www.runryder.net/helicopter/gallery/15767/


< Message edited by Furious Predator -- 1/18/2008 11:36:25 PM >

(in reply to dixielandsbigal)
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RE: Long lasting gas powered Sailplane - 1/19/2008 6:04:12 AM   
OzMo



Posts: 1434
Joined: 9/2/2002
From: OZark, MO, USA
Status: offline 		A Dynaflight Butterfly with an LA 25 at high Idle will fly untill your tired of it! And that 99" span could lift an old school camara.
I added spoilers to mine but it really doesn't need 'em. <