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4s or 3s battery for tricopter

#1
My tricopter is using Sunnysky 1400kv motors with 8045 props, a 2200 mAh battery, and 13" booms. It's a titan tricopter with the company's recommended setup for macro flying. I'm new to flying multi rotors and the way it is now the controls are very touchy. I can fly it pretty well with the KK2.1.5 board in self-level mode, but my landing are always harsh even with the throttle curve adjusted. I'm sure my transmitter needs to be adjusted more, but I'm wondering if it would be better to learn on a 3s battery first. If I switched to a 3s battery, would I need to change anything else on my tricopter?
 

baddox

Senior Member
#2
I don't think the battery is really a problem here. 4S might be overkill for that setup, but the flying characteristics you mention are more appropriately dealt with by modifying your transmitter and/or flight controller settings. To make the controls less touchy, turn down the rates on your transmitter and add some expo.

To make your landing smoother probably just takes a bit of practice. Multirotors can be tricky to land at first, because of the turbulence and ground effect when the rotors get close to the ground. While you're learning, you can even make some flexible landing gear out of zip ties:

http://flitetest.com/articles/diy-landing-gear-for-multirotors

http://www.rcgroups.com/forums/showpost.php?p=27078440&postcount=31

FYI, I have run a 4S battery on my Titan with 1250 and 1000 kv motors, with both 8 and 9 inch propellers. I haven't done any real tests regarding efficiency or flight times, but all the setups have worked quite well, with no noticeably bad flight characteristics.
 

x0054

Senior Member
#3
I would curve the throttle on the transmitter, I don't know, I always like more power :) Is it currently hovering at mid stick? If not, I would adjust the curve until it's hovering at mid stick and flatten the curve out around the hover point, so you have more control for fine adjustment while hovering. Also, really soft landings are a bit hard. Usually you can come in close to the ground, but once you are 1-3 inches off the ground, you should just kill the throttle. At least in my experience, trying to land that last inch or so very softly result in the skid touching the ground, which sends a jolt to the accelerometer, and that makes the quad jump up again. You not going to hurt anything letting it fall that last inch.
 

Craftydan

Hostage Taker of Quads
Staff member
Moderator
Mentor
#4
Two words . . . Throttle hold. don't know which TX you're using, but if it supports a latched throttle hold switch, you flip the switch and the motors cut off. If your radio doesn't have it built in, but has mix settings you can likley program it in there.

Slowly sink to the ground as flat as you can and just before you touch, flip the switch and fall the last few inches. You'll look like a pro, every time ;) (don't flip the switch by accident 100' up . . . that's a lesson you don't learn twice :p )

Switching to 4S will likely make it worse, I'm afraid. The higher voltage (on smaller props) gives you more agility and power for the same weight, making the lill bugger even more twitchy. You'll likely *want* the bigger batteries eventually, but until you've got a good mastery of the airframe, you don't want the extra power -- it'll only get you into trouble faster and break it worse.

BTW, double check your sunnysky's specs -- some of their motors can handle 4S fine . . . some cannot.
 

Balu

Lurker
Staff member
Admin
Moderator
#5
(don't flip the switch by accident 100' up . . . that's a lesson you don't learn twice :p )
Does it count, when I'm lower than 100'? Because I've done this three times so far and I'm really thinking about disabling my "motor safety switch" function on the Taranis... :)
 

x0054

Senior Member
#6
If you arm via switch, you can also just disarm an inch from the ground. Oh, and if flipping switches accidentally is an issue, you can always install one of those cool covered switches. I am actually thinking of doing that for my arming switch. Never had an issue of accidentally hitting it, but those covered switches look cool :)