Heavy Lift
10-09-2011, 12:34 PM
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Heavy Lift
Building a micro class heavy lift airplane hopefully weighing 3lbs including electronics and payload, I'm having trouble deciding what battery to use for 10-15min flight time using a brushless 400 motor, any thoughts would be appreciated.
10-10-2011, 05:32 AM
#2
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RE: Heavy Lift
Look at the motor specs to see what the amp draw is for the prop you plan to use. Then get a battery with enough capacity to provide those amps. The flight time you're talking about is pretty long though for a heavy lift contest. Most of those are just one circuit around the airfield and a landing. Since you'll be at full throttle the whole time when loaded, are you sure you need to fly for 15 minutes?
10-10-2011, 05:40 AM
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RE: Heavy Lift
Yeah a 15 minute run time is just about a heavy lift contest for any RC electric.
I had the Cherokee set for a 6 minuet run time and need a 5S 5,000 mAh pack for that. That pack filled up the cabin so I decided to go with a Super Tigre 46. in the Cherokee since is a over weight ARF anyway. I'll have to build a light weight .60 size plane to use the Cherokee's electric power system in.
I had the Cherokee set for a 6 minuet run time and need a 5S 5,000 mAh pack for that. That pack filled up the cabin so I decided to go with a Super Tigre 46. in the Cherokee since is a over weight ARF anyway. I'll have to build a light weight .60 size plane to use the Cherokee's electric power system in.
10-10-2011, 06:58 AM
#4
RE: Heavy Lift
Three lbs all up wieght for a micro class with no landing gear being either a hand launch or bungee/cart launched is a bit high. What % is payload? A micro type glider is most likely the optimum configuration. Very small power plant needed to maintain flight as the hand launch gets you up to flying speed. Look at something like an indoor slow flyer application and we get quite long flights on a 400 3S lipo cell. This will get you a motor, speed control, reciever and battery pack for grams instead of ozs.
Dennis
Dennis
10-10-2011, 09:33 AM
#6
RE: Heavy Lift
ORIGINAL: AmishWarlord
Can you post the contest rules for the event?
Can you post the contest rules for the event?
http://students.sae.org/competitions/aerodesign/
I am with the University of Windsor team and pilot thier entry. Here is the maiden flight of last years entry that placed second in the advanced class.
[youtube]http://www.youtube.com/watch?v=g8xC-pE6RoA[/youtube]
10-10-2011, 11:08 AM
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RE: Heavy Lift
"3.2 Competition Circuit Requirements
The aircraft must successfully complete one 360° circuit of the field."
You don't need fifteen minutes for that. Should be able to do that in well under two minuets.
You need just enough to get up and make the circuit with just a tad extra for the dang head wind you WILL have that day on take off.
The aircraft must successfully complete one 360° circuit of the field."
You don't need fifteen minutes for that. Should be able to do that in well under two minuets.
You need just enough to get up and make the circuit with just a tad extra for the dang head wind you WILL have that day on take off.
10-10-2011, 11:15 AM
#8
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RE: Heavy Lift
Are you coming to the contest in Fort Worth? If so I'll probably see you there.
At the one we host, flights are rarely over 2 minutes, and only that long if you miss your landing approach the first time. If you design for 4 minute flights you should be fine.
At the one we host, flights are rarely over 2 minutes, and only that long if you miss your landing approach the first time. If you design for 4 minute flights you should be fine.
10-10-2011, 02:44 PM
#9
RE: Heavy Lift
ORIGINAL: jester_s1
Are you coming to the contest in Fort Worth? If so I'll probably see you there.
At the one we host, flights are rarely over 2 minutes, and only that long if you miss your landing approach the first time. If you design for 4 minute flights you should be fine.
Are you coming to the contest in Fort Worth? If so I'll probably see you there.
At the one we host, flights are rarely over 2 minutes, and only that long if you miss your landing approach the first time. If you design for 4 minute flights you should be fine.
Dennis
