Notes
I have a redesigned v2 frame that is a true-X design to align the carbon fibre with the arms and hopefully have a much stiffer frame. Furthermore, I have another frame design coming that is suited for the longer 450 3s batteries built around the jhemcu 16x16 AIO board that will also have a reduced stack height. I am aiming for 12mm standoffs.

Intro
The Serenity frame is my attempt at creating a freestyle oriented 2 inch build that flies more like a 5 inch. This build is heavier than typical toothpick builds, but I aimed to be lighter than some of the older BNF 2 inch models like the lizard since we now have access to much more modern components. My main goals were sub 100g AUW with a 450 mAh 3s battery top mounted to have nice smooth handling.

Design Process
The biggest constraints on the physical dimensions were the battery mounting and the camera mounting. The motors had to fit around both of those components. I chose the short Tattu 450 3s lipos as I thought that would make for a better center of mass. I decided on an H style frame since that would give me the shortest and therefore stiffest arms. Once I had a design laid out that had enough room for the camera, I made a 3d printed prototype at my school's makerspace. After making a few adjustments on the camera mounting (switching to 3d printed mounts) and beefing up the frame I put in an order to CNCMadness and was very happy with the end results. Only 11.5g with 16mm m2 aluminum standoffs and steel screws! The baseplate is 2.5mm carbon and the topplate is 1.5mm carbon.

Components
At the time I first started putting together this build 2019, the best stack was the mamba 16x16 nano stack. I have had a few problems with this stack so I wouldn't recommend it but at the moment I can't say what the best alternative is. I would preferable want an fc/esc that doesn't need header pins since those are known to break easily in crashes. I am looking at the helination talon 16x16 stack, the hgrc fd13 stack, or the flywoo goku f745 stack as alternatives and may mix and match for certain features like blackbox. For the power system, the Dab 1104 motors seemed like the best 1104 motors on the market (maybe the only ones) and I heard a lot of good things about the Gemfan 2023 props, but I plan on trying out a variety of the 2 inch props on the market. The Runcam Nano2 and TBS Pro32 nano vtx were the best options for video when I was buying components. With all these components it seemed like I was just on track for hitting my target weight:

11.5g frame + 5.5g stack + 4x5.7g motors + 3g camera + 1.5g vtx + 1g receiver + 4x 0.8g props + 6g( strap, ummagrip, hardware) = 54.5g dry or 98g with 450 3s.

The Build
The build turned out quite well, my most clean build to date. The weight of the drone came out to be 61.1g with the original tbs antenna, and fsd nano receiver. After switching to a truerc d-pole and ghost zepto receiver (with xm antenna) the build came out at 59.4g. This is a fair bit higher than my estimate but it is easy to underestimate the hardware and miscellaneous peices. The build video describes the build process and shows a flight video at the end to demonstrate flight performance. After performing a 2 pack UAV-tech slider tune, it flies very smooth and is a dream to fly in a park around trees. I hope that this build will open up playgrounds as viable freestyle spots.

Build video will be coming

Build Notes
A couple notes if you want to build this yourself. I built this with 16mm M2 standoffs. You could try with 15mm standoffs but that might be a bit tight. The frame will fit most 14x14 nano cameras (soldered wires) but it will be tight. It is designed for a 16x16mm stack only. The tattu square 450 3s batteries are the recommended batteries but some of the newer 300-350mah 3s batteris may be short enough to fit.

Here are the files for the first version of the frame with the camera mount: https://www.thingiverse.com/thing:4305457/files

Recomended Components
There are a variety of components that can work with this frame. A couple guidelines to follow are to shoot for an AUW of around 100g with a battery and use motors that output ~200g thrust for a TWR of 8:1. If using smaller motors and smallers batteries ie(1103 10000kv / 450mah 2s) shoot for an AUW of around 80g and motors that produce ~120g thrust for a TWR of about 6:1.

Recommended Components

Motors: Hypetrain Dab, T-motor 1203, T-Motor M1104

ESC/FC: Goku F4/F7, Heli-Nation Tiny Talon JHEMCU GF16 and GHF13 AIO
Goku fc's have dataflash chips for blackbox logging. The talon esc is the only 16x16 mount 32 bit esc. GF16 is the only F405 flight controller GHF13 AIO is the lightest option

Cameras: Caddx Ant, Runcam Nano 2/4, Caddx Baby Ratel 2, Foxeer Razer Nano 2
Foxeer Toothless Nano 2 (Pad version) and Foxeer Pred 5 (Pad version) might fit but it will be tight

Vtx's: TBS pro32 nano, Eachine nano 2, NamelessRC nano, HGLRC Zeus nano or your preferred nano vtx

Receivers: IRC Zepto, Happymodel EP2
Any other nano/micro sized receiver of your chosen protocol, 2.4G is better since the antenna's are smaller and lighter. Surface mount antennas save a lot of space.