This is a review of the BetaFPV HX115 SE, a 3-inch Toothpick FPV drone powered by 1S LiPo battery. It’s very light weight, quiet and safe to fly in local parks, and yet it offers extremely high performance.
If you are new to this drone class, here is the introduction to custom built 2.5″ toothpick and 3″ toothpicks.
Table of Contents
Where to Buy HX115 SE?
There’s only 1 RX protocol option – Frsky SPI (D8/D16).
- Banggood: https://oscarliang.com/product-q4tr
- BetaFPV: https://oscarliang.com/product-6it9
- GetFPV: https://oscarliang.com/product-ls28
- 1x HX115 SE Toothpick FPV Drone
- 1x 1S 450mAh LiPo Battery (BT2.0 connector)
- 2 sets of HQ 3020 bi-blade Props
You should get some spare props (3020 with 1.5mm holes): https://oscarliang.com/product-rggj
HX115 SE Specs
- Frame size: 115mm
- Motor: 1102 18000KV
- Propeller: HQ 3020 2-Blade Propellers 1.5mm Shaft
- Flight controller:F4 1S 12A AIO FC
- VTX: A01 25-200mW VTX
- Camera: Caddx ANT camera
- Camera Tilt Degree: 0-60°
- Receiver: SPI Frsky FCC D8/D16
- Battery connector: BT2.0
- Recommended Battery: BT2.0 450mAh 1S LiPo
- Weight without battery: 39.1g
Closer Look
The BetaFPV HX115 SE is in the same class as the famous KababFPV 1S 3″ toothpick. The main difference is that the HX115 SE uses smaller 1102 motors with 1.5mm shaft.
The quad alone weighs 39.1g, 51.4g with a 1S 450mAh LiPo.
- To get more spare batteries: https://oscarliang.com/product-t30n
- You will need a charger with BT2.0 connectors: https://oscarliang.com/product-v5db
Normal LiPo should only be charged to 4.20V, but these batteries are LiHV, meaning they can be charged up to 4.35V.
When taking the canopy off, I found the nylon screws are extremely easy to strip. Eventually I replaced them with some steel ones, they are less than half a gram heavier. (1x M2 12mm, 2x M2 4mm)
The FPV camera and VTX are mounted separately inside the canopy. The camera is the Caddx Ant, image quality is pretty decent for a tiny camera this small and light weight. You can see the image quality comparison here. The radio receiver is integrated in the FC, which supports Frsky D8/D16 (ACCST V1).
Most of the 1S flight controllers on the market have only 5A ESC, but the new BetaFPV F4 1S Toothpick FC have integrated 12A ESC that’s capable of driving 3-inch propellers. FC product page: https://oscarliang.com/product-65ni
The F4 FC has two UART’s and they are both free for your disposal.
Since the FC has solder pads for motors, it’s entirely possible to upgrade the motors even if they don’t have connectors.
Two of the FC screws extrudes from the bottom and might dig into your battery, loosening those screws a tiny bit fixes it.
Flight Performance
The HX115 SE is really quiet, you can barely hear it 30 meters away.
The power to weight ratio is absolutely insane due to the high KV motors, and pretty power hungry too if you fly aggressively. It hovers at 20% throttle and feels super light in the air. Although hover time can reach 5:30 with the provided 1S 450mAh LiPo, when you really punch that throttle, flight time can be drastically reduced to under 3-minute.
It’s got some oscillations in flight, wobbles quite a bit when it’s wind, and there’s prop wash when doing slit-S probably because the small motors and they lack torque. Above 70% throttle, there’s no noticeable change in RPM, the motors just can’t handle those 3″ props.
It handles much like a 2.5″ toothpick. Flight performance will definitely benefit from some further tuning on filters and PID. It appears they did attempt to tune the PID in factory, but I think there’s still room for improvement.
Range is around 200-300 meters, fairly typical for an integrated SPI receiver. If you want more range, I think the HX115 SE would be a great platform for the ExpressLRS 2.4GHz RF system. Not only it will give you decent rage (a couple of km easily), its 500Hz mode can drastically reduce control latency and make the quad feel more connected. UART 1 and 2 on the FC are both free for additional RX, as VTX SmartAudio is connected via Softserial.
How to Setup Betaflight HX115 SE
Board: BEFH/BETAFPVF411RX(STM32F411), it comes with firmware version 4.2.9. You can find CLI dump here.
First, binding RX to radio. To enter “bind mode”, in CLI, enter bind_rx.
In Modes tab, assign switches to arm, beeper, Flip Over After Crash.
Configuration Tab:
- Set arming angle to 180
- Enable ESC Beacon (RX_SET only)
Power & Battery Tab:
- Minimum cell voltage: 2.9V
- Maximum cell voltage: 4.39V
- Warning cell voltage: 3.25V
Setup Rates and OSD screen to your preference.
That’s it, you are ready for first flight.
The ESC’s are using “Z-H-30” BLHeli_S firmware, 16.70. There doesn’t seem to be new firmware for this to enable RPM filter or 48KHz at the moment for this particular target.
Conclusion
I really like this 1S 3″ concept, it’s super quiet and flies amazingly. Also it’s pretty harmless compared to a full power 5″ quad. The OG KababFPV build might be the best right now in this class, but it’s always out of stock and especially difficult to get for non-American pilots, it would be great if there’re other alternatives.
The BetaFPV HX115 SE could have been that alternative if they use better motors and tuning.
It’s quite powerful for an 1S quad, perhaps a bit too much vibration, it could be a lot better if they try larger motors with lower KV, like 1202.5 11500KV, or the even wider 13mm motors that are recommended by KababFPV. The 1102 motors used here are considered slightly too small even for 2.5″ builds, of course they would lack the torque for 3″ props.
But I imagine upgrading the motors would probably also require upgrading the BT2.0 battery connector to XT30 in order to keep up with the increased current demand. XT30 is heavier, but it has less resistance than BT2.0. That means they would have to invest in making a whole new type of battery as they don’t currently offer 1S 450-600mAh LiPo with XT30 connectors. It’s going to be costly for them.
Update – Upgrading Motors
I tried to upgrade the motors to 1202.5 11500KV.
Note that the original motors use 3 screws.Although the frame has holes for the four-screw motors, they are slightly too close together, and don’t fit motors with 9mm diagonal mounting pattern. For the RekonFPV 1202.5 motors I am using, I can only fit 2 adjacent holes. This is clearly not ideal, but I am still doing this just to see how it performs. I will probably replace the frame later.
I am still using BT2.0 connector in this test.
It flies much better, much more locked in and throttle response also more linear. Flight time is slightly less, just above 2 minutes of aggressive flying. You can still cruise til 3 minutes mark, but it feels powerless and RPM doesn’t change much when you punch throttle. I think we just hit the limit of the BT2.0 connector and LiPo at the end of the pack.
Overall I think the larger motors are a worthy upgrade. I changed the PID.
My current PID:
set throttle_boost = 0 set p_pitch = 100 set i_pitch = 65 set d_pitch = 75 set f_pitch = 0 set p_roll = 100 set i_roll = 65 set d_roll = 70 set f_roll = 0 set p_yaw = 90 set i_yaw = 85 set f_yaw = 0 set d_min_roll = 20 set d_min_pitch = 22 set d_min_boost_gain = 27
Filters, move both Gyro and Dterms to the left two notches to get rid of excessive vibrations in flight.
8 comments
Hi Oscar,
thanks for the Review! it really helped me out!
I got the impression that my hx115se whobbles a lot. I contacted betafpv about this and asked if it could be due to the PID / filter tune, but they suspect that one of the motors is broken and will send a new one. we will see…
In addition, I have had an unusual number of RX losses so far, although I have positioned the RX antenna as freely as possible.
And the VTX gets very hot at 25mW and switches off after 30 seconds on the bench, apparently it needs airflow to work properly.
I hope replacing the motor will improve the whobbling…
Do you have any other recommendations on these topics?
This quad is just by nature very wobbly out of the box. Some PID retuning might help, but I haven’t had time to try it yet. Maybe at some point this week. Like I said in the review the motors are a bit small so it’s not gonna be perfect when it comes to flight performance.
FpvCycle sells 1s batteries with Xt30 connectors already attached. They’re sold in packs of 3. If you swap the pigtail on this drone, you could just use those. Granted, I’m not familiar with shipping restrictions, so that might be a barrier for some.
I’d be curious to see how this performs with the fpvcycle babytooth motors + props.
Nah, it looks like US vendors don’t normally ship batteries abroad because it’s too expensive, I tried.
I bet it would fly similar to the FPV cycle if we change the motors and battery, maybe a tad heavier due to the frame, but still better than what it is right now.
Hey Oscar,
thanks for all your reviews, helped me a lot to get into this hobby :)
I just bought this one as my first outdoor quad and i also noticed that it wobbles sometimes.
do you have any recomendation on how to tune this thing (or in general how to tune quads, am kinda new in the fpv world) ?
And also is there a quad you would say that it would be worth having as second one, there are so many and i dont know which one could be good for a beginner.
I will try to play with PID/filter and make an update later this week.
I think ultimately we have to change out the motors and battery connector if we want better performance :)
and also, are you able to turn on bidirectional dshot?
I could not get it to work, betafpv said that it should work with blheli but i always get the errors “MSPRPMFILTER” and “DSHOT_BBANG”
I had the same issue with my Meteor65, try “set dshot_bitbang = off ” in CLI and save.