ORIGINAL: aflipz
Well, you need a 2000mah lipo if you are going to need the amps (ex 10c lipo 2000mah= capable 20 amps continuous)
My motor, prop and esc setup draws about 10 amps. so i could get away with a lighter battery, benefiting from lower weight, but ultimately dropping some flight time...
But as you said, that's if the plane is nice and light. If it's heavy, then you need more power, which means more battery, which means more weight, which means more power which....
I can imagine it's a viscous cycle!
I'd really like to know the empty airframe weight with control surfaces, horns and linkages. adding that weight to the weight of my gear would give me a ballpark idea of how much the all up weight would be. If the total is 17oz, then what am i waiting for? take my credit card!
Mine, with 3 Futaba S3108 servos (7.6g each) weighed 256g. So subtract out the servos and you've got 233.2 grams.
you know what, there is no better way to get an answer than to order one and build/weigh it myself, right? i'm gonna do that right now!
And at this rate, you'll probably be flying yours before me!
my 300 will have a hs-56 servo operating the ailerons (more torque and strength, but only 1 gram more than a hs-55) i will either use hs-50's for the elevator and rudder or hs-55's. I'm gonna get really retarded with the weight shaving on this one. every non critical bit of foam will be cut off grinded out or sanded down. All wires will be cut down, motor will be directly soldered to the esc (those bullet connectors are really heavy) Since i will be using less than 15 amps i am going to use deans micro plugs (about a gram per pair) instead of the 6 gram ultras etc.. As i said before i will thin down all epoxy used with large amounts of micro balloons AND will use it as if it were pure lead; very very sparingly.
I expect to spend about 10-20 hours working on weight reduction after the airframe is gutted for weight reduction, built and fitted with servos etc. It's a painstaking process to do what i plan to do, because to achieve lowest weight you need to have the plane naturally ballanced by it's necessary components instead of adding fore or aft ballast, This means a lot of soldering, shortening or extending wires etc until everything is truly optimal. My e-flite yak 54 (recomended by tmaniaci) comes in at 14oz all up including my "heavy" 1320 pack, it's got a LOT of unnecessary, large gauge wire, connectors, servo wire etc. It also has a very heavy hs81 servo for the ailerons (my hs-50 gears stripped in testing, again) and a couple of reinforcements up front that i could have done without... (battery holder/fuselage doubler, not used with heavy packs) aswell as a few other things i can think of... If i replaced that hs-81 with a hs-56, cut the connectors out, direct soldered the esc, shortened all extra wire and ditched the landing gear it should be near 12 oz. change the pack for a 900 and i'd be looking at around 11 oz!
I never use extensions for my servos.. they are too heavy, Instead i cut the wires and solder the lenght of wire needed using minimal amounts of lead and very short, smallest shrinkwraps possible. I also have a bunch of carbon fibre rods and tubes lying around, i'll try to replace as much metal as i can with it. There is a good chance that i'll make it a belly lander too, because imho they create too much drag in the air to begin with, not to mention bumping final weight up 14 grams (plus the plastic insert and adhesive used to secure it to the fuselage)
I may plan on doing some of the lightening stuff as well. If you do anything like that, please post up what you did and your results. If you want to include that in my Extra thread, that's fine with me. Oh, use the foam canopy though. It's lighter than the plastic one.
When you look at the video on the ultrafly website, there are no decals on the extra 300s. look how nice it flies, looks very light on it's wings. No surprize that the plane has no decals or trim, and that it is being flown with the foam canopy... I agree with tmaniaci and everyone else, for a plane 22oz in weight you'll need a heavy 2100 pack and a brushless setup drawing 20 amps or more... BUT, if you can get it to weigh 17oz i'm sure you can get away with much much less power, still climb vertically as easily and need a lot less airspeed to stay airborne, thus "cool down" the landings considerably.
Yeah, I guarantee they flew/video'd it with no decals for the weight reduction and improved flying characteristics. Now some have said it looks a bit twitchy. But if you look carefully, it was rather windy on that day. You can see a flag blowing in the background. I don't know... I guess we'll find out how good it flies with reduced weight.