World's smallest racedrone yet!
The video above offers a complete narrated introduction of the Minimus 45, my latest micro quadcopter frame design which opens up a whole new road to explore and develop! Some DVR flight footage will be shown at the end of the video.
Alot of technological improvement and innovation have been going on the last few years since Tiny Whoop has been introduced to the community. Flight controllers became advanced programmable powerhouses, motors became faster, and the first user-friendly brushless setups allready entered the scene a while ago. One thing never really changed though: the frames.
I allways wondered if it is possible to make a smaller micro FPV vehicle with the same components used in a Tiny Whoop.
The Minimus 45 is my answer to this question. Measuring 70 by 70 mm including shrouds and having a diagonal motor to motor distance of 45 mm, this frame is 30% smaller than a Tiny Whoop!
The only way to achieve such a small frame with the current Tiny Whoop electronics is by mounting the motors upside down (pushprop setup) in such a way that the propellers are situated far enough below the main board to have access to all the air it needs to deliver maximum performance. If the propellers are too close to the main board, they dont have enough access to free air to thrust through and will therefor perform mediocre or even bad.
The Minimus 45 3D print files are available for free on Thingiverse in 2 different versions with each a different licence to it.
1 version is a complete frame, including camera mount and battery mount, designed for a specific array of electronics which i will list below. If you just want to build and fly the Minimus, and you are willing to shop up the necessary electronics, this version is the way to go! This frame can be 3D printed with a non-commercial/non-edit license. You are allowed to print the frame for yourself or your friends, but you are not allowed to edit or remix it.
A second version of the Minimus comes as a barebone frame. It does not have a camera mount or a battery mount. This barebone frame is OPEN SOURCE! This frame version is ideal for everybody who wants to use different camera units and/or different battery setups. The barebone also comes with a non-commercial license but you ARE allowed to edit it. The CAD files are at your disposal so you can create your own variations of my Minimus frame to fit your own setup and to share it with the community.
The Minimus 45 is developed and optimized for ABS filament. Test prints have been done with a Zortrax M200 with a 0.4mm nozzle and a layer resolution of 90 microns. So i recommend to print at a layer resolution of 100 microns or less.
The Minimus 45 is designed to be printed hollow, with 0 (zero) infill! I print with 6 surface bottom and 6 surface top layers to close up the print.
The main frame and the shrouds are printed separate, both having the same printer setup. Use 45° supports, especially for the shrouds. Avoid using supports in the 4 slots that will allow the flight controller to be snapped in. That would be hard to remove. Your printer should be able to bridge them. (See picture below on the right)
The Minimus 45 is designed to fit any board that fits a Tiny Whoop. An Alienwhoop zero works great, so would any Betaflight board.
A regular Blade Inductrix FPV flight controller shows noticeable oscillations due to it's firmware which is not developed for such small frames. Adding weight and providing balanced propellers could help a little.
Currently, The Minimus 45 only supports 7x16mm motors. A version for 6mm motors will be made available later.
For the complete frame with camera mount and battery mount, you need a VM275T style aio camera/vtx unit with dipole antenna and 40x17x6mm 1-cel 240 mah lipos from Mylipo. Similar lipo batteries can also be used with perhaps a little modification to the frame. Below are a few links where to find the camera and lipo's. This list can be extended if i find more sources.
AIO camera/vtx unit
VM275T style aio camera units are pretty easy to get by. Below some examples:
The minimus 45 has been designed for these Mylipo batteries, so they are a perfect fit. I know they are not widespread available but if you can get your hands on them, do it!
This is an alternative currently available in the USA at Amazon. The dimensions are a little different compared to the Mylipo battery and a small modification to the frame may be needed. The Eachine battery is advertised with a thickness of 7.82 mm while a mylipo battery has a thickness of about 6.5mm. An easy way to make this battery fit is by sanding the part pointed out on the image below on the left.
Regular Tiny whoop lipos can also be used as an alternative. But i recommend to not use the very long 250-260 mah ones since they are just ridiculously long for this very small frame. 205 mah Tiny Whoop style batteries are a pretty good fit but your flight time will be rather limited.