What is the diference between the Flat and symmetrical blades? more lift? more agile? what is the lowdown.

flat blades give more lift are suppose to be more efficient in hover.

Symmetrical blades provide no lift other than what is provided by blade pitch but will allow for inverted flight. Most people have commented that symmetrical blades also allow for more head speed and track better resulting in more overall feeling of stability.

Flat blades will also give you a slower translational roll which if you're learning is something you will want.

how much pitch/roll rate is best for a beginner is very debatable: too quick=overcorrections, too slow=overcorrections. imo, regardless whether you use flat or symmetrical, a beginner can adjust pitch enough to get the pitch/roll rates where he/she likes them.

i've trained a few pilots who did better with symmetricals during the hovering stage. i've also trained a couple other pilots who prefered the slow response of the flat bottom blades. i prefer letting beginners figure out what they are most comfortable with, and try not to recommend which type of blade is best. instead, i try teaching them what vortex05 said: how each type will affect the heli's performance.

one more thing:
keep in mind that if you have a heli setup for one type of blade, you'll have to change pinion gears when you switch to another. ie: a cp pro is setup for symmetricals, so you have to drop a tooth on the pinion if you bolt flat bottoms on it. on the other hand if you have a cp, which is setup for flat bottoms, you'll need to add a tooth to the pinion when you bolt on symmetricals. the reason for all this madness is flat bottoms create the same lift at lower speeds, so you need to drop a tooth with them to keep the motor in it's "power band".

Thanks that helped alot!

just got a cp today.....haven't gotten to fly it yet.

so if I use symetricals with the stock pinions what is the downside? Is it still workable? and if I use the 9 tooth from the aerobatics kit, will it still perform well with the Ni-MH?

Guess i am just impatient because I want to try it out tomorrow morning, but won't have time to run to LHS for parts. The guy I bought it from had a damaged set of flats and an unused aerobatics kit. So I was going to try it out after just changing to the symetricals

a stock cp (non pro) with symmetricals attached have very low lift, which makes it barely flyable. so no, it doesn't work.

no, pretty much the only thing that will work with stock nimh is 10T & flat bottoms. the 9T is intended for 3S lipo & symmetricals.

check out this thread for all a comprehensive guide on which pinion is used for what battery/blade combination:

[link=http://www.rcuniverse.com/forum/m_4467139/anchors_4467285/mpage_1/key_pinion%252Cflat%252Cbottom/anchor/tm.htm#4467285]http://www.rcuniverse.com/forum/m_4467139/anchors_4467285/mpage_1/key_pinion%252Cflat%252Cbottom/anchor/tm.htm#4467285[/link]

truglodite

you seem pretty knowledgable about blade/pinion/battery/lift....

what do you think of the Thunder Power 2100mAh 3-Cell 11.1V Lipo on a Blade CP Pro with stock motor and CF Sym blades?

I'm looking to increase my flight times any recommendations?

thanks for the info truglodite....

I figured that was the case, but I am dying to try this out....been flying my cx2 for a while now...

thanks for the link...some great stuff there.

Lookyj,

The TP 2100mah is way too heavy for the CP/CP Pro. These helicopters are most efficient when flown light. If you are looking to tame the heli down and get longer flight times, I would suggest the megapower or DN Power 1350 pack, which you can find at helidirect. Stay away from the Sonix 1200 pack, it claims 15c and I can say through experience that is bull.

I have been flying for almost a year and really like the feel of packs that weigh around 68 grams. I just bought two DN Power 10c 900mah packs from readyheli for $15.95 each. I fly the DN 2150 15c packs in my TREX and they are great. Hopefully the 10c packs are good.

hmmm that's interresting.

currently I'm running 9T with CF blades.

I got fed up with how unstable the flat blades felt maybe this is because I really should've switched the motor to a 8T as I'm currently running 3S lipo battery (11.1v) after my nimh packs died on me.

Amazingly I'm experiencing significantly less crashes with the CF configuration in fact the only minor damage on the blades was due to me carrying it and accidentally hitting the idle up switch on my transmitter. (sometimes i really wish there was a trottle lock switch so you can power up the transmitter and not actually make it live until your actually on the field. Useful for those winter months when you don't want to take your gloves off to plug the battery in.

I think the best suggestion is to try both and find one that suits you, make sure to give at least 3 full flights to each configuration as that's how long I feel I take to get used to a blade configuration to be able to hold it stable consistently. Recently I'm finding that CF sym blades do alot better with a slight breeze a sudden change in wind direction usually throws me off way more when running flat bottoms due to the much lower response time, but with the CF I can usually correct well before I get into trouble.

it'll work with a 9t motor w/ sim blades w/ stock ni-hm batt. no, it wont be efficient, no, it won't have crazy punch outs, probably slow as a snail, i've tried it. flat blades provide more lift, more or less stable? there's different opinions about it. i find the sym blades to be more stable after you've adapted to it, because sym blades will produce lower lift than flatties per headspeed, you'll need more headspeed to get the same amount of lift opposed to the flatties, higher headspeed will increase gyroscopic effect and make it more stable, however, you'll get faster and cripsier cyclic, that when not used to, will say it's twichy, but one must know that a bird can be stable AND twichy. if you want it to be more stable, less twichy, and longer flight times, get the tp1320, if you want 3d, get tp910.

np guys.

lookyj, bdp282 is right about the 2100mA, it's way too heavy. you're motor will chug too many amps to lift the extra weight, so flight times may not improve over 1320 times. you'll find the blend you like for your blade somewhere in the 900-1300mA range. i support chopperdudes advice: use heavier packs for sport and training, lighter for aerobatics.

i like my tp910's more than my 1320 for the kind of flying i do. i notice less flight time during aerobatics with my 1320, because the extra weight takes much more energy to toss around. on the other hand if i'm not chucking the heli around, i prefer the relaxed feel and extra flight time the 1320 gives during hovering, slow ff, and in very windy conditions. the 1320 feels less reactive than the 910.

chopperdudes, i like your description using "lift per headspeed"; that makes it much easier for ppl to understand the dynamics involved.

read on if you feel engineery:
flat airfoils have a higher lift coefficient (Cl) than symmetrical blades. higher Cl means more lift at a given speed and angle of attack (or pitch). high Cl (aka hi lift) airfoils are generally more efficient for slower moving objects. so a flat bottom blade (higher Cl) will create hovering lift at lower headspeed with the same pitch. also, with the same headspeed, flats will produce hover with less angle of attack.

the reason we fly flats slower than syms instead of just reducing the pitch is stall. syms have a lower Cl than flats, so they need more pitch to hover. as you reduce the headspeed, you're more likely to hit the stall angle of attack with symmetricals because of this.

the simplest way i can describe lift coefficient is "lift per pitch".[]

I put flats on my CP Pro and never adjusted the pinions. I have only hovered a little bit inside due to weather around here, but it seems okay. Should I really still change pinions?

since the pro has a lipo pack, it'll be ok to use flatties. it'll have alittle bit more lift, but will be less stable in the wind. you really shouldn't change pinions.

I've heard if you change to 8 pinion gear the motor will last longer also the speed of the blades will be slower and lift will be addaquit[sm=confused.gif]
Is this correct?
Ed

Ed,

See Post #7 of this thread, it's a comprehensive, battery, pinion gear configuration. It all depends on your needs and type of flying you want to do. Just click on the link.

Dave / Choppersrule

How does elevation (air density) play into all this? I read a review of the CPP in RC Flyer (I think) that the tester changed to a 10T because he was in Colorado (incidenally where I happen to be). However the Pinon thread says you will burn up the motor with a Lipo and 10T.

Spike5150,

I see there in Castle Rock, that you're at 6,200 feet elevation. I live south of Indianapolis, IN. I'm about 720 feet elevation.

BIG difference in elevation.

Don't believe everything you read, I ran a 10T stock motor on my Pro for many months with no problems. I've gone to a brushless motor awhile back.

I'd give it a try, worst case scenario, burned upped $10 motor. I love to experiment with the helis, that's part of the enjoyment for me.

If concerned about damaging the controller, you could add a 7.5 automotive fuse in series to the hot lead of the motor.

Dave / Choppersrule