Recently picked up an AlfaRC Fi-135 budget 3" frame for $18 which can mount an O3.



The bottom plate is 3mm and comes tapered. The top plate has 20x20 and 25x25 mounting holes for the VTX. With the TPU fittings it comes close to 40g.
I had some old parts laying around that I've been meaning to use, don't remember which build they came off of or why?! Hopefully all is still working.

Since I don't have any extra O3s, I had a Avatar Pro camera/VTX that I had mounted to a 2.5" build but never tested, time to pull it off.

The motors were Axisflying C135s, which are actually 1303.5 sized and not 1305s as the model number would suggest. I had smashed up one of the motors in a crash, so one was a new replacement. The c-clips were too large for the arm holes, so I had to drill them out. In hind site, I should have been a little more patient and ground them out instead, the drill bit I used left some rough spots.

The AIO was an older Hakrc F411, I am guessing it has 20A? ESCs. No blackbox, but it has a baro and a MPU6000 gyro

After installing everything, the build was a little heavier than I expected. I believe this is the heaviest 3" build I have. I am thinking maybe the 1303.5 motors will be a little small to handle the weight, maybe I should have gone with 1404s?



The Pro camera does have a long lens, and just sticks out past the frame. I decided to add a lens hood for a little protection, but that probably wouldn't do much in a direct hit. Also as the frame was designed for the 20mm wide O3 camera, I had to print two 0.5mm spacers to get the camera to seat nicely between the TPU inserts.

There is plenty of space between the VTX and AIO. For the AIO, it is mounted with the gummy directly on top of the bottom plate, without any nut in between. As the screws are only securing a single board, it feels quite solid.
The ELRS RX has a cube antenna, and is mounted in the back with the antenna facing down.



It maidened wthout any issue on a 3S 550mah pack. Happy to say the motors were not lacking and felt they had plenty of punch even for some light acro. The wind had died down this evening, so that probably helped. But I was quite taken by how smooth the drone flew. The C135 motors were quite smooth, the frame was stable enough, and I think the older FC with the MPU6000 definitely made a difference too.

Here is the maiden footage without any stabilization. Not sure why my goggles did not record, so no OSD.


The TPU camera mounts were not perfect. Looking at the camera gyro, probably 90% was fine, but in some spots you could see vibrations in the gyro where the image was solid. The insert is quit an odd shape, so might take some work to match it with a custom print.

The antenna performed terribly though, kept getting RSSI warning everywhere and transmitter constantly ramping up. Have to switch out to one with a dipole antenna.

Thanks. I am looking for another 3" to build. I will check into this one. I want a frame with the camera in front and low to the ground. I have enough 3" toothpick with the camera on top.

For 3" there are many options with camera mounted up front. Even for AlfaRC, I think they have like 4 different versions of this frame. The one I got is a little larger and taller to accommodate the O3, but if you plan on some other VTX/cam maybe a different version would be more suitable. They have one with a simple CF plate (no TPU inserts) as well as one with CNC rails like the Tadpole.



Otherwise some other 3" frames I've had good experience with if you want to try something different, but again there are so many choices.

Pickle Evo2 Mk3 (cut by CNCm)
Super thin arms, but deadcat layout. I went with the multiplate 2.5mm version and surprising it flies quite well and stable with some T-motor 1204s. It has multiple bottom plates and you can sandwich a TPU shim between, I think that helps.
https://youtu.be/tX71poeO-jc?t=1

BetaFPV HX115LR
If you want to go 2S and build really light. I don't think they stock this frame anymore but @skywanderer uploaded the cut files so you could have them cut. Not the most stable/hardy frame, but can be extremely agile, fun, and super flight times. You will need to push the camera to mount in front of the standoffs though if you want props out of view.
https://youtu.be/Nvc1F0uLGOU?t=1

Ductless Cinelog 30
This is the old version which you might find on sale, just need the 3 plates assuming you have standoffs/screws in your kit. It is a push configuration so props are more exposed, but it has a built in suspension mount that is very effective eliminating jello if you plan to carry an action camera. You do get some props in view depending on your camera angle, but the action cam is usually clear.

I had a look for me as i'm in the market for a 3-3.5" frame and while I couldn't find the Fi-135, I did find an Fi-150 (on Xinte). It's ordered (along with two other smaller frames. Now I can eventually get the 1408 build online.

(25-Jun-2024, 02:44 PM)mstc Wrote: For 3" there are many options with camera mounted up front. Even for AlfaRC, I think they have like 4 different versions of this frame. The one I got is a little larger and taller to accommodate the O3, but if you plan on some other VTX/cam maybe a different version would be more suitable. They have one with a simple CF plate (no TPU inserts) as well as one with CNC rails like the Tadpole.



Otherwise some other 3" frames I've had good experience with if you want to try something different, but again there are so many choices.

Pickle Evo2 Mk3 (cut by CNCm)
Super thin arms, but deadcat layout. I went with the multiplate 2.5mm version and surprising it flies quite well and stable with some T-motor 1204s. It has multiple bottom plates and you can sandwich a TPU shim between, I think that helps.
https://youtu.be/tX71poeO-jc?t=1

BetaFPV HX115LR
If you want to go 2S and build really light. I don't think they stock this frame anymore but @skywanderer uploaded the cut files so you could have them cut. Not the most stable/hardy frame, but can be extremely agile, fun, and super flight times. You will need to push the camera to mount in front of the standoffs though if you want props out of view.
https://youtu.be/Nvc1F0uLGOU?t=1

Ductless Cinelog 30
This is the old version which you might find on sale, just need the 3 plates assuming you have standoffs/screws in your kit. It is a push configuration so props are more exposed, but it has a built in suspension mount that is very effective eliminating jello if you plan to carry an action camera. You do get some props in view depending on your camera angle, but the action cam is usually clear.

Thanks for your thoughts on those frames. I will do some research. Yes I am all for light weight but found that there is a sweet spot. Too light and the quad tends to jump around a bit in a slight breeze because of the turbulence close to the ground. My flying style is trying to duplicate the Star War pod racing. Just close to the ground with the ground rushing up and try not to hit it.

Those AOS T3 toothpicks are my go to quads right now because they are small light and quiet but they do bounce around. The QAV S Mini is my waterproof 3" and is pretty smooth albeit a little on the heavier side and just a tad nosier. 

Amazingly the Air Blade Transformer 4" is doing very well. That is what is leading me to build something just a tiny bit smaller still.

I am also thinking about using one of those AOS 3.5" frame and using only 3" props and motors to get a little more prop clearance. Most of these builds have propeller edges so close to the hardware it makes me paranoid.

My whoops are not getting flown much because they are heavier and more noisy. Except for the 65's and 75's indoor.

(25-Jun-2024, 06:27 PM)SeismicCWave Wrote: using only 3" props and motors to get a little more prop clearance.

This is what i intend to do for the 1408.  They are rated for 3-3.5" but I will probably use the HQ 3x3x3 on them as they are pretty durable.  I have heard/read/watched things saying that most 3.5 props are a touch fragile.  I do have some HQ 3.5 props as well.  I've had good success running say Azure 2035 on a 2.5" frame, so I would expect the same on something bigger.

(25-Jun-2024, 06:39 PM)Pathfinder075 Wrote: This is what i intend to do for the 1408.  They are rated for 3-3.5" but I will probably use the HQ 3x3x3 on them as they are pretty durable.  I have heard/read/watched things saying that most 3.5 props are a touch fragile.  I do have some HQ 3.5 props as well.  I've had good success running say Azure 2035 on a 2.5" frame, so I would expect the same on something bigger.

Yeah I have a hunch that using a smaller diameter props may not be a bad thing. Especially when matched properly with battery cell count and motor kV. I remember when I was designing and building those larger multicopters frames we were pretty concern about prop clearance. Having props too close together were not good for stability. That's why I was pretty surprised at how close these modern day quads are flying so well. The flight controllers are definitely much much better nowadays.

The one concern I have is the smaller props with larger frame will be disk loading. Sometimes that may be a good thing for a smoother flight. Maybe not as good for aerobatics or long range.

I wouldn't be too concerned with props coming close together, as long as you have wiring/parts secured down so they cannot get in props way. The components tend to be quite heavy and compact in comparison to say a large light wing which would act like a sail. The turbulent air coming off the sides of the props is probably not significant compared to the amount of downward thrust the prop is producing. If you have an extremely light build or super flimsy props, then it might be a different story.

As you mention, plenty of modern frames have very tight prop clearance, but on the most part I've never seen any errant behavior. If you block/deflect the downward thrust, that is another matter.

Having the props wider apart will make the quad easier to control and less squirrelly. But if you like floaty feel, just cruising, or want better efficiency, probably less noise as well, then go with larger props assuming the motors are sized accordingly. But it is an easy swap so you can play around and go with your preference. But if you are going for podracing, those were very narrow crafts? Maybe try a t-bone setup!?!

too funny, ask bing about your AlfaRC Fi-135 fpv frame, their ai chatbox spews this out:

Quote:Certainly! The AlfaRC Fi-135 is a budget-friendly 3-inch frame that you recently picked up for $18. Here are some key details about it:

Construction: The frame features a 3mm tapered bottom plate and a top plate with 20x20 and 25x25 mounting holes for the VTX.

Camera Compatibility: It’s designed to mount an O3 camera (20mm wide), and you might need to use 0.5mm spacers to fit it nicely between the TPU inserts.

Motor Size: You’ve used Axisflying C135 (1303.5) motors, which are slightly smaller than the 1305s.

Electronics: Your build includes an older Hakrc F411 AIO FC (with MPU6000 gyro), an Avatar Pro camera/VTX, and an ELRS RX with a cube antenna.

Flight Experience: Despite being a bit heavier than expected, the drone flew smoothly during the maiden flight, thanks to the smooth C135 motors and the older FC.

Here’s the maiden flight footage without stabilization. Enjoy flying your cruiser!

...mstc, you should try those same axisflying c135 motors on a 3.5" sythe or similar lite frame setup...

another cool build from your lab!

You blew my cover. I am powered by OpenAI, photos by Dall-E, and flight video from Sora. Need to start using a different seed to get a different flight environment 

 hahaha!

(25-Jun-2024, 08:06 PM)mstc Wrote: I wouldn't be too concerned with props coming close together, as long as you have wiring/parts secured down so they cannot get in props way. The components tend to be quite heavy and compact in comparison to say a large light wing which would act like a sail. The turbulent air coming off the sides of the props is probably not significant compared to the amount of downward thrust the prop is producing. If you have an extremely light build or super flimsy props, then it might be a different story.

As you mention, plenty of modern frames have very tight prop clearance, but on the most part I've never seen any errant behavior. If you block/deflect the downward thrust, that is another matter.

Having the props wider apart will make the quad easier to control and less squirrelly. But if you like floaty feel, just cruising, or want better efficiency, probably less noise as well, then go with larger props assuming the motors are sized accordingly. But it is an easy swap so you can play around and go with your preference. But if you are going for podracing, those were very narrow crafts? Maybe try a t-bone setup!?!

I did mine, because under certain conditions the prop was hitting the canopy.  Clearance was mm's.  I went from HQ 2.5x2x3 to Azure 2035.  The power loss was negligible.  It could still do a powerloop and every other trick I know.  Battery usage was bit more though.  But for me it really depends how close to the canopy the props are. 5mm+, yeah not bothered, run full size, less than 5mm, maybe underprop.  But it's not a hard rule, it's (for me) a case by case basis.

(25-Jun-2024, 08:42 PM)mstc Wrote: You blew my cover. I am powered by OpenAI.

This would explain a lot, like why you are never seen in videos you post.

Quote:Certainly! The AlfaRC Fi-135 is a budget-friendly 3-inch frame that you recently picked up for $18. Here are some key details about it:

Construction: The frame features a 3mm tapered bottom plate and a top plate with 20x20 and 25x25 mounting holes for the VTX.

Camera Compatibility: It’s designed to mount an O3 camera (20mm wide), and you might need to use 0.5mm spacers to fit it nicely between the TPU inserts.

Motor Size: You’ve used Axisflying C135 (1303.5) motors, which are slightly smaller than the 1305s.

Electronics: Your build includes an older Hakrc F411 AIO FC (with MPU6000 gyro), an Avatar Pro camera/VTX, and an ELRS RX with a cube antenna.

Flight Experience: Despite being a bit heavier than expected, the drone flew smoothly during the maiden flight, thanks to the smooth C135 motors and the older FC.

Here’s the maiden flight footage without stabilization. Enjoy flying your cruiser!

Even AI thinks the new FC's are shite and the only good gyro is MPU6000.

(25-Jun-2024, 08:06 PM)mstc Wrote: I wouldn't be too concerned with props coming close together, as long as you have wiring/parts secured down so they cannot get in props way. The components tend to be quite heavy and compact in comparison to say a large light wing which would act like a sail. The turbulent air coming off the sides of the props is probably not significant compared to the amount of downward thrust the prop is producing. If you have an extremely light build or super flimsy props, then it might be a different story.

As you mention, plenty of modern frames have very tight prop clearance, but on the most part I've never seen any errant behavior. If you block/deflect the downward thrust, that is another matter.

Having the props wider apart will make the quad easier to control and less squirrelly. But if you like floaty feel, just cruising, or want better efficiency, probably less noise as well, then go with larger props assuming the motors are sized accordingly. But it is an easy swap so you can play around and go with your preference. But if you are going for podracing, those were very narrow crafts? Maybe try a t-bone setup!?!

I am not so worried about the aerodynamic of a close together propeller anymore. However the disadvantage is the other things like antenna and other wiring. I had the prop hitting wires when I was not careful. Made funny thack thack sound and not good for the performance.

Yeah I watched the T Bone setup but that's a bit extreme.. Maybe something in the same vein. Just a little narrower than a true X. I actually do like a bit of prop showing on the screen. Gives me a bit of reference when I am aiming the quad.

I also found that I am much more comfortable with the camera pointing a low angle. I can be a lot more precise with altitude. That's why I like frames with cameras in the front.

I am suprised Bing will give an answer based on a sample size of one data point, just shows how unreliable AI "facts" are. It did a very nice job of recapping though, A+ for that.


Lol time to get out the KK and CC3D boards...

Quote:You

what is the best gyro for a drone flight controller

Copilot

When it comes to choosing a gyro for your drone flight controller, there are a few options to consider. Let’s explore some popular choices:

1. BMI 270 vs. MPU6000
   • These are two commonly used gyros in FPV flight controllers.
     
   • The BMI 270 appears to have a slight edge over the MPU6000 in terms of noise levels and flight performance
     
   • Lower noise levels typically lead to smoother flight and better handling during challenging maneuvers.
     
   • Keep in mind that software support for the BMI 270 is improving, making it an attractive choice for FPV enthusiasts.
     
2. Other options:
   • KK 2.1.5 flight controller board uses the MPU6050 gyroscope and accelerometer.
     
   • Ardupilot APM 2.8 flight controller board features a 3-Axis Gyrometer, accelerometer, and high-performance barometer.
     
   • OpenPilot CC3D flight controller board also includes a 3-Axis Gyrometer and accelerometer.
     

Remember to choose a controller that balances responsiveness and stability based on your flying style and preferences! [url=https://www.dronetrest.com/t/bmi-270-vs-mpu6000-which-gyro-reigns-supreme-for-fpv-flight-controllers/9951]?✨

Is ICM42688 better or worse

Quote:The ICM-42688-P offers some advantages over other gyros, but whether it’s “better” depends on your specific needs:

1. Precision: The ICM-42688-P has impressive noise levels for both gyroscope (2.8 mdps/√Hz) and accelerometer (70 μg/√Hz). This can lead to smoother flight performance.
   
2. Features: It supports wake-on-motion, tilt detection, tap detection, and significant motion detection. These features are valuable for various applications.
   
3. Resolution: With 19-bit gyroscope data and 18-bit accelerometer data, it provides high-resolution measurements.
   

However, it’s essential to consider compatibility with your flight controller, software support, and overall system requirements. If these align well, the ICM-42688-P could be an excellent choice! ?✨

I know @mstc and I can confirm he has AI levels of information in his noggin. He also has an incredible ear and can always hear when my quads are running poorly with marred props and other issues (this is all of my quads).