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-   -   Help please! =) (http://www.Wattflyer.com/forums/showthread.php?t=73297)

guiche 03-07-2014 12:31 AM

Help please! =)
 
hello:D,
I'm trying to build an airplane that i want it to be able to lift around 25 lbs but to use no more than 900 Watts. Any advise on an electric motor and propeller?

fhhuber 03-07-2014 12:34 AM

I suggest a lot of helium.

pizzano 03-07-2014 12:47 AM

More than likely....it will require multi rotors and a lot more than 900 watts to lift 25lbs.......

Check this site out:

http://www.multirotorforums.com/forum.php

There are a few ideas there that may stimulate a few grey matter cells....;)

hayofstacks 03-07-2014 02:05 AM

380 watts on 3 cells and a 15x8 prop can get you 6lbs of thrust.

Id run two motors to give you about 12lbs of thrust, which should marginally lift 25lbs, but you would need more then that if the 25lbs doesn't include the plane. plan on 3-4 motors running more like half throttle.

Why a 900watt limit?

Mivins 03-07-2014 02:15 PM

I think he said airplane and not multirotor. I suspect he may be engineering a plane for a competition to carry a specific cargo. I suggest a very efficient motor and esc combination and high discharge battery that will supply only enough juice to complete the necessary time in the air required to complete the task to keep the weight down. You did mean airplane and cargo weight total of 25lbs? Someone on this forum will know the right 900 watt motor. Good luck, Marty

guiche 03-07-2014 04:57 PM

Quote:

Originally Posted by hayofstacks (Post 941740)
380 watts on 3 cells and a 15x8 prop can get you 6lbs of thrust.

Id run two motors to give you about 12lbs of thrust, which should marginally lift 25lbs, but you would need more then that if the 25lbs doesn't include the plane. plan on 3-4 motors running more like half throttle.

Why a 900watt limit?

Hi, thank you for your reply. The limit is because I have a power limiter that will cut off the power at that range. This is for a project and there are restrictions. I'm also limited to one motor, and a 4 cell lipo battery. Besides the two motor option do you think I got other options? :confused:

Mivins 03-07-2014 06:03 PM

25lbs of payload
 
You need to start supplying more information if you want useful advice. Do you intend to build a plane that has a specific airframe size, weight, length, or wingspan? Does the all up weight of the airplane need to be 25 lbs. or just the cargo you are carrying? There are a lot of motors that will produce enough power to use 900 watts. Finding one that will do that at 4S will limit it some, but typically using the slowest KV rating and swinging the biggest prop it can handle at 900 watts should get it in the air if you can build a high lift plane without a lot of weight. So what does the plane need to look like?????
Good luck, Marty

hayofstacks 03-07-2014 11:01 PM

Yeah, id find a 250ish kv rating prop and test 20" or larger props. the motor alone will likely weigh over 20oz and your going to be very limited on a single 4 cell battery how long it can fly.

pizzano 03-08-2014 02:15 AM

Quote:

Originally Posted by Mivins (Post 941825)
You need to start supplying more information if you want useful advice. Do you intend to build a plane that has a specific airframe size, weight, length, or wingspan? Does the all up weight of the airplane need to be 25 lbs. or just the cargo you are carrying? There are a lot of motors that will produce enough power to use 900 watts. Finding one that will do that at 4S will limit it some, but typically using the slowest KV rating and swinging the biggest prop it can handle at 900 watts should get it in the air if you can build a high lift plane without a lot of weight. So what does the plane need to look like?????
Good luck, Marty

+1 Marty.......I too was wondering what "lift" meant....aka cargo carrying, pulling, lifting....ect., ect.,ect.......?

Larry3215 03-08-2014 02:27 AM

It all depends on the airframe.

It should be fairly easy to design an airframe that will take off and carry a 25 lb payload on 900 watts. The question is - how far and how fast and how high and how long does it have to fly?????

Is there a budget? Any other restrictions? Requirements?

You mentioned 4 cells and 900 watts - what other details are available??

We need a LOT more information.

You cannot just pick a motor and expect the rest to just happen mysteriously.

An aircraft is a system. All the parts have to work together to achieve the goal.

We have no idea what the parts are or what the goals are or what the limits are :)

CHELLIE 03-08-2014 04:15 AM

Quote:

Originally Posted by guiche (Post 941816)
Hi, thank you for your reply. The limit is because I have a power limiter that will cut off the power at that range. This is for a project and there are restrictions. I'm also limited to one motor, and a 4 cell lipo battery. Besides the two motor option do you think I got other options? :confused:

We Need A HECK of a lot more info :eek: Is the 25LBs separate of the Aircrafts weight, what are your restrictions ???? We Need to know them, how far does it have to fly, how high does it have to go, how fast does it need to be, how big of a lipo are you restricted too, how big of a motor are you restricted too, how big of a prop are you restricted too, ???? ???? ???? We Cant help you with very very limited info.

CHELLIE 03-08-2014 04:25 AM


CHELLIE 03-08-2014 04:30 AM


http://www.youtube.com/watch?v=bD94OiElVoo

Turner 03-08-2014 04:47 AM

Quote:

Originally Posted by CHELLIE (Post 941893)
CCRC Heavylift Competition 2011

That is very cool. That looks like a lot of fun. It's a different sort of flying but I really think I'm seeing a bunch of people that really love RC flying. Nice find Chellie.


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