This build idea started when Tyrdle in the Broke FPV discord server posted a link to some dirt cheap AeroSky motors on eBay ($35 for 5x) and said they might be good for a 10" build. Since I had been looking into something more efficient than my 5" quad for long range flights, I decided to start planning out this build.
I started by looking for a decent frame, I originally thought I might go for the iFlight XL10 but Tyrdle ended up designing something because he thought it would be cool. Inspired heavily by the FPVCycle Glide the "Assassin 10" frame was born:
I went ahead and got this cut at CNCMadness as a 2 pack for a friend of mine to build one as well since it was cheaper that way and he wanted to take advantage of the cheap motors too. Normally motors for something like this are $30 for 1, being able to get 5 for that price was a steal. For the rest of the components I settled on Master Airscrew 10x4.5x2 propellers, a Kakute F7 Mini (not budget I know, wanted to try ArduCopter), a Mamba F40 ESC I had sitting around, a Rush Tank Ultimate Plus, a Caddx Ratel, a BN-880Q GPS and Crossfire since I wanted the most reliable link for a quad of this size. I originally had the regular Tank Ultimate but I put the build together and it fried itself in the air for no reason.
Now, as of writing this I'm not sure that I'd recommend the frame to everyone just yet as I'm having some vibration issues. I'm still not positive if it was the frame or the motors though, because the first flight was a runaway and crash landing because I decided to select the 10" preset in iNav not knowing that it was originally designed for lower authority quads, and mine proceeded to shoot to the moon almost instantly:
I also busted 2 props, conveniently both the same type so I didn't have any spares available. It took a couple days to get a few new ones in from Master Airscrew. So the vibrations could be coming from the motors because of this crash, I have no reference for what a clean motor performs like. Anyways, after this I ended up flashing Betaflight since for some reason the iNav blackbox software was giving me trouble and I figure I could tune there first and transfer the pids when I'm ready. The sliders in the Betaflight configurator also help a lot with the process. After a bit of tuning this is the final result:
It doesn't fly perfect by any means but I've improved the tune since then and am currently limited by the noise issues something is causing in this setup. Astro in the FPV server did a build similar to this with the XL10 and didn't wreck it immediately and doesn't have the vibrations I do on the same props and motors (his not being smashed into the ground) so I'm pretty confident it's either my motors or my frame causing D-term oscillation issues because of the noise.
Because of this I actually ended up ordering some higher quality NSK bearings from iFlight's website (10x4x4 and 9x4x4) to see if they'd make a difference or not. I ordered from iFlight's website because other retailers wanted around $13 for a single bearings and iFlight only asks for $3/bearing. At the time of writing I still haven't gotten them though.. Hopefully they help, if not I'll probably be swapping it for a more rigid frame if that turns out to be the issue. Interestingly enough I tried softmounting my FC to dampen the vibrations and that somehow made the noise worse. I'll update this post as I get my new bearings in and report what happens.