55mm prop to 65mm prop - Retune?

Hey gang, I’m curious to know what kind of retuning should I expect when increasing the prop size on an already tuned brushed quad in regards to PIDs? Currently, I’m using either Afunta-type or LB props and running Spintechs with great results - now I’m wondering about larger props. - hehehe
In the next week or so, I should be receiving my KingKong Props with my MMW Darks and hopefully a plethora of additional parts - can’t wait!!!

@chime13
I’m by no means a PID guru, but I have done this (changed props) and had no ill effects.
Granted this was a while back before I knew about Joshua Bardwel, and all of Betaflight’s major updates. I was also on a F1 Scisky.
That being said, I suppose you could go a couple of ways w it. 1) adjust your existing tune w new props to your liking or 2) CAUTION: type default in CLI, and start from scratch. It will set all parameters back to stock. Not me though. I have enough on my plate, and just want to fly even if it is w a tune that’s not perfect.
@NotFastEnuf or @PJC are my go to guys for PID, I have a ton of their stuff bookmarked for that never ending hunt. Honestly, I usually wreck my frame before I get that far!!

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The closer to perfect your tune was for 55mm the more likely you’ll need to retune for 65 I expect.
Before you do ANYTHING though, go to cli and save a “dump all”. That gets EVERYTHING, not just the current profile and such.

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Just use another pid profile. Keep your profile for 55mm on number 1. Set up #2 to be a direct copy and we can adjust it from there. No way to know exactly what it will need till you fly it. But record a session where you try to force out as much bad behavior as you can after the prop swap and we’ll help you dial it in. :smile:

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Micro tuning techniques - different than larger quads[quote=“NotFastEnuf, post:22, topic:3860”]
What usually does require a big pid adjustment is different size props.
[/quote]

Yea, THIS guy😉

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Hey @NotFastEnuf, @Kamsleo69, and @Bobnova! I appreciate all the feedback!
Yes, I understand using profiles and such, but my mis-spoken question I guess should have started with my thoughts, and that of which I’ve read regarding larger props and hi-perfomance motor such as the Dark Editions.

What I’m wondering is:
A 65mm prop will require more torque to spin-up and will require more torque to stop due to increased mass and momentum, than a 55mm prop. This in turn should cause more heat buildup in the motors. So, theoretically, should/would the PIDs be lower or higher than the existing 55mm prop build?

That one I don’t know about, really.
Brushed motors only accelerate the props, no active braking to be had there, but they do require more torque to spin a given speed and therefore generally run hotter.

My admittedly minimal testing has a bit lower P with larger props, for whatever that is worth.
For bonus points a 65mm prop at 8000’ elevation may be more like a 55mm or 60mm at sea level, except with worse cooling due to thinner air.

Anyway, I’d start with lowering things I think.

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My thoughts, Exactly! But…it’s usually 65-75F degrees when I fly up here, so from past experience, my motors run much cooler than they did at +90F at sea level - hahaha

I’m thinking P and I will go down and D will probably remain or even go up…

It depends really and could go either way. If the motors are strong enough to change the speed of 66mm close to as fast 55mm, then you would probably drop a little. I run slower 8.5’s and had to tune up because the 66mm props change speed slower than 55’s on my motors so I needed the pic controller to ask for changes with more force. It really depends on your motors.

I would imagine that most would require tuning up but I have only tested hubsan replacements and silver 15’s.

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You see? All I had to do was ask the right question and I’d get the right answer - Thanks @NotFastEnuf!

I guess I’ve been talking too much spanish lately…hahaha

Todo esta bien amigo. Es la misma cosa en cualquiera idioma. Vuelelo. If it oscillates tightly … you gotta drop. If it oscillates loosely, if the bobbles are large … you gotta go up! :wink: You’ll know by the first hard turn.

If it tries to fly away … drop D.

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Gracias Hermano @NotFastEnuf! I’m still a couple of weeks away before my Wife returns from the US with my goodies, so yawl have ta wait ‘til I can let yawl know if my 65’ers make a difference in 8700ft - vs 55’ers AND what kinda tunin’ I had to endure. - jejeje

Paz

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Have y’all watched @Benedikt’s recent video on motor efficiency? Some are so efficient that I imagine they wouldn’t run hot if the props fell within the motor’s efficiency ranges.

Just wondering out loud…

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In my experience, spintech motors that are 8.5mm 15200 kv with gemfan 65mm props get hot, very hot! lol please let me know ur experience!

They say 57g thrust with parrot prop (which is 66mm I believe) 48g thrust with husban prop … they run cool on 55mm afuntas…

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