NEWB Trouble with holding altitude (not altitude hold)

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i_build

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Finished my build with an I Flight succex F7 mini FC 4 in 1 esc and 2306 2450KV motors running 3s 5" props on a carbon fiber Mark 4 frame using Beta Flight 4.2.9 and Dshot 600 and rpm filtering. It's my first quad... and I have a sim that I don't have issues with staying level at a slow cruise. But I just cant with my quad... it's like I'm always adjusting throttle to the point that I really can't enjoy flying. I spend more time trying to hold altitude... than actual maneuvers... I even tried using the PID values from the sim to no avail. I can hear a different pitch of the motors when it either looses or gains altitude so something is signaling the FC to change the rate even on just a simple hover. I know BF doesn't do alt hold and I expect to make some minor adjustments to throttle but I didn't think I would have to chase it all the time... at least I don't have to in the sim. I don't have anything to compare it to except a DJI Mavic that a friend has... and I know that has a ton of other features to help it remain level so it's not a fair comparison. And I don't have anyone else with a built quad to compare it to also or neither have I flown another quad... so I am trying to figure out is it just me and the quad and config is fine... or is it my skills or lack thereof (then I dont understand why I do so well in the SIM) or is it something I am missing with the PIDs. I tried slight changes using the BF sliders... is there any config that might help me have the ability to remain as stable as possible regarding altitude. I tried flattening out the throttle curve at my hover point also just in case it had to do with my hands not being steady... but that did not work either. Please help. Thanks.
 
Guessing this must be a dumb question... I'll keep reading, and hopefully I'll find the answer just too wide a range of possibilities.
 
Hi been think about your problem in a hover if it keeps changing rpm of motors it may be a vibration problem most of the time it's the FCB to tight or too loose
How is your mounted ?
 
I printed 4 short TPU bushings and since the flight stack is 20mm the Mark 4 frame I purchased is pre-drilled in 2 places to accommodate mounting (center and rear) but I am only using the center for the entire stack. I ran the long screws for the stack up through the bottom of the frame and then placed the TPU bushings on those screws. Then I have the 4 in 1 esc with soft mount inserts in each hole... then the FC with soft mounts inserts.... then the VTX with soft mount inserts. To hold it all down I used the 4 plastic nuts that came with the FC and fastened each down with equal tension all showing about 3 threads on each screw. I can crank them down as hard as possible cause there is more room for tightening.

Does that sound correct? Not sure what is too tight or too loose?

I even tried INav with Alt Hold on the same setup with baro covered in foam and via black box the altitude is generally correct but I can still hear the pitch of the motor change and I get these dips and climbs out of nowhere almost as if I touched throttle and I have to chase them in INav similarly to BF just tuning angle mode in INAV first since that is the basis for all other nav modes... but same thing on both.
 
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Trouble shooting is just a try it and see , so make it tight and try it , FCB can be of hit and miss so it's worth a try
 
Throttle control just takes a lot of practice. I'm guessing you're flying fpv? You have to constantly be giving it gas and letting off. You do it without even thinking about it after a while.

The sims aren't really an accurate recreation of actually flying but the do give you a good starting point.
 
I think I made a dumb mistake. I was thinking that I should get a high Mah so I can get a bunch of practice in so the 3s I am using is 5200 mah and pretty much runs the entire length of the quad. I think my power to weight ratio is bad with that battery and probably has some impact (I am guessing here.) on the stability. I will try to find what the right size is and buy multiple batteries instead of 1 huge battery,
 
Yeah that battery is way too big. I recommend a 1300-1500 for 5" kwads. Race Day Quads.com sells some excellent brands and I can usually find 3 or 4s sizes as I use both. Try the cnhl or the rdq brands. Very solid batts.
 
Yup get 3 or 4 with that capacity (1300-1550mAh) and a parallel charge board with fuses can charge them together so long as starting voltage is close (with a tenth or two of a volt between two packs they will self level between them if voltage diff too high the fuse on parallel board will blow)
 
If you can't exchange the big one can usually use it as a supply for recharging things on the go or for goggle or tx battery power since does store a lot of power just might need buck converter to drop the voltage a bit depending on what feeding the power into.
 
It's nice to have the big mah but the weight is a real killer , hobby king was working on quad batteries low weight big mah may be worth looking into some time
 
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