Motor Upgrade for F450

[azure]

I've got an F450 frame that I've set up for FPV with the stock 2212 motors and 30A DJI ESCs, that I'm running with 8x5 Graupners, 4S. The batteries are either 4200mah or 3300mah, 455g and 361g respectively. AUW is right around 1600g. I'm flying NAZA in manual mode and am finding that the quad is pretty sluggish on the vertical axis, with it real easy to get behind the power curve in fast descents. Also, I can't seem to get the gain settings where the motors are not surging / oscillating during high powered maneuvers. I've tried adjusting the gains anywhere from 140 down to 90 to no avail. And at 90 it's a total pig, and it still stutters.

I've done a bunch of searches here regarding motor upgrades that will fit the 450 arms. Most of the posts that I've been able to find have been from a few months ago recommending Suppo, Tiger, Avroto, AXI, etc. I'm wondering if anyone has some current thoughts about what's well suited to this frame at high weights... and what might fit without modification of the frame, or at least a minimum about of modification; a few holes or an adapter plate is fine. I'd like to stay with the DJI 30A ESCs if possible. Thanks in advance.

 

[rwijnhov]

keep the motors use 10x5 graupners at 4s and all is well.

 

[azure]

But wouldn't the lower disc loading of the 10x5 make it worse? Isn't using a larger prop like trying to climb a hill in high gear when driving a car, where it puts added strain on the engine?

Also, I come from a full-scale, fixed-wing A/C background where high wing loading (i.e. a short, thin wing) is preferred for high G-force maneuvering, and we use a fine-pitch prop setting with higher loading for take-offs and climb. I was taught in school that the rotor on a heli was analogous to a big spinning wing. So, wouldn't it apply here?

When I put the 450 / NAZA in ATTI there is no problem with surging / oscillating when doing punch-outs, but flying normally in MAN the 2212's stutter starting at about 75% power if the rotors are loading up in a maneuver.

 

[kloner]

if you want power, you want 28mm motors. problem is that you have a 16mmx19mm motor mount and that's pretty much limited to 450 size motors. i use 480 size motors, 2814 suppo 1000kv and with 4s and 10" props it does 700 watts. my stock 2215's did just over 400. These have a 19mmx19mm mount so your only able to use 2 screws or the dji fram needs a couple holes drilled over existing holes. i haven't had a problem with using 2

looks like this, first punchout was atti, second one is manual

 

[azure]

@ Kloner: Is the video done with the Suppo 2814 or the stock DJI 2212? The stuttering I'm getting in MAN is similar to what you are showing when punching out in manual, though in my case it's way more pronounced.

 

[kloner]

there 2814's

you want to back off the manual gain a little at a time and that'll ease up for ya. theres a point where you want a little so on the flip side of the coin, it is stable when flying around. but if that things wa,wa,wa in on ya, it makes it tougher to get atti setup

 

[azure]

Yeah, I understand regarding backing off on the gains. I'm hoping the bigger motors will help, cause when I try backing off the gain with the 2212's to fix the "wa wa wa", the throttle response just gets too low.

If 2814's fit with just two extra holes, I'll give it a try. Thx.

 

[kloner]

what are the gains set to?

these have the 16x19 bolt pattern so all four screws go in, but there rated for 3s (though ran 2217 on 4s and they are still flying in another guys flamewheel)
http://www.altitudehobbies.com/brus...ess-motor-peak-450-35-28-1000kv-suppo-2810-12

 

[azure]

Now at 110. I've gone as low as 90 and as high as 140.

Thanks for the link, but I've got all 4s batteries. Do you see drilling a couple holes for the Suppo or Avroto 2814 being a problem?

And BTW, your FPV rig inspired me for my build. I will post some pics and video later today.

 

[kloner]

you'd need a really nice drill press with a vise or a mill to seriously drill the holes perfectly. i think 2 holes is fine, have lvc'd mine from 200 feet up to the ground like 3 times and no problems with 2 bolts. 40ish hours in now but i use blue loctite just for piece of mind

Glad to drag you down with me :02.47-tranquillity: these things are addictive as hell

you've obviously gone through the gains....... props are totaly balanced? That makes a huge difference

this was a flight or two earlier, kept getting this in atti, had a gain switch for atti that didn't do squat to help, but dropping manual gains made it look like the first punchout above

 

[kloner]

better example, manual mode punchouts, see how the craft wanted to dart off to the sides

 

[azure]

you'd need a really nice drill press with a vise or a mill to seriously drill the holes perfectly. i think 2 holes is fine, have lvc'd mine from 200 feet up to the ground like 3 times and no problems with 2 bolts. 40ish hours in now but i use blue loctite just for piece of mind

Glad to drag you down with me :02.47-tranquillity: these things are addictive as hell

you've obviously gone through the gains....... props are totaly balanced? That makes a huge difference

this was a flight or two earlier, kept getting this in atti, had a gain switch for atti that didn't do squat to help, but dropping manual gains made it look like the first punchout above

Yeah, money pit, time suck, but addictive.

Been using the HK prop balancer. Seems to work fine, though the Graupners don't need much tweaking.

 

[DennyR]

I am running those motors on a RCTimer Hexa with 9x4 props. Impressive all round performance.
Naza setting are 150 basic on roll,pitch and yaw, 85 on atti.
Great windy weather machine.

 

[azure]

I am running those motors on a RCTimer Hexa with 9x4 props. Impressive all round performance.
Naza setting are 150 basic on roll,pitch and yaw, 85 on atti.
Great windy weather machine.

Which motors? And what is your basic throttle / vertical gain?

 

[azure]

Based on the advice that I got here and other info that's been posted, I picked up a set of Avroto 2814s from Patrick at AMP yesterday (good guy, BTW). I'm going to try with both 8x5 and 10x5 Graupners to see how they compare.

 

[kloner]

look forward to hearing what you think

on my 28mm motors, i'm settling in on 9" graups seems to peak around 600 watts and the motors come down cool, flights seem steadier, on 4s. Mine likes the 10" with 3s. mid stick manual and mid stick atti are exact, same with the 9" and 4s. the 8's on 4s mine wants to have a higher hover throttle in man, and in 10" with 4s mine hovers at 1/4 throttle. makes flipping into atti from manual interesting and overall less stable. i'm 1650g - 1800g depending on packs rtf

 

[azure]

So, I made the motor and prop change-over on the 450 and was able to fly it briefly before a crash (unrelated to the mod). With the new Avroto 2814s / Graupner 10x5s combination all the oscillating problems in Manual Mode have gone away, and it's nice have an adequate power reserve for maneuvering. Thanks all for the suggestions.

That being said, I'm having a weird issue in ATT Mode though, where the throttle is doing this twitching thing. I'll be hovering smoothly and the with smallest throttle change, it'll jump up and down before settling down again. In MAN it's totally fine. I've tried a variety of throttle gain and ATT gain settings (70 - 140), but no improvement. Maybe you guys have some suggestions? My gains, which are working well for the FPV flying I'm doing - pretty much all in MAN Mode - are: Basics: 140 140 155 80 Att: 100 100

 

[kloner]

The one you have 80 that is vertical gain, try bumping that up to 100-120. your atti gains are pretty high, might try lowering those as well.

 

[azure]

The one you have 80 that is vertical gain, try bumping that up to 100-120

I did, but it doesn't seem to make a difference. And higher than V80 in MAN it starts becoming too sensitive. If the compromise is MAN over ATT, I'll stay with the MAN setting because that's how I do most of my flying, but it would be nice if both modes worked well. I'll keep messing with it. Maybe I'll try going even higher than 120 on the V gain?

 

[kloner]

somethings not right sounding. make sure no heat in motors when you land. if there is, check balance. the only other thing i can think of if that doesn't make it feel right for ya is to try making a throttle curve with a flatter spot in the center, like expo if you will. On mine i made throttle hold 50% to deal with keeping a level flight when i want it