2.5" heavyweight

By yohfpv on Mar 24, 2022

7  181  2

Well well well...what a little bundle of joy this turned out to be. I've only flown it once and I'm already smitten.

The idea here was to build an slightly faster but notably heavier alter-ego to my lightweight, 2s quad for flying at nighbourhood parks. The goal being to get a high-inertia quad that is still small and quiet enough not to trouble other people. Something that could be flung around with plenty of carry at zero throttle. Something with which to try and learn a new style of flying.

A 5-inch could obviously have accomplished the same flying characteristics but would be loud and aggressive, very likely to disturb other people so I decided against flying 5-inch at the smaller neighbourhood parks.

In the maiden flight I flew with very little camera uptilt, somewhat less than 20 degrees, just being cautious, not knowing the nature of this little beast. Needless to say, flying on 4s with so little uptilt it was already as fast as my 2.5-inch at 40 degrees uptilt so I guess there might be some insane speed waiting to be tapped in future.

Since this build and tune hasn't been optimized yet, I might add updates to this page in future. Some ideas that I have for it that I would like to try later would be to switch it to Emuflight (currently Betaflight), load Bluejay ESC firmware (currently stock BLHELI_S), move the battery to top-mount location and maybe to change out the pigtail for thicker gauge wire. Also to change out the renovated old Eachine VTX03 with its repaired linear antenna for something new that will mount neatly on the 20x20 stack. Will have to wait and see where I go with this one.

Here is the DVR of the maiden flight:


The standard HGLRC Hornet frame leaves the motor bells hanging over the edges and vulnerable to hard knocks during crashes. So, I've decided to craft some carbon fibre motor protectors by grinding up a spare BetaFPV 85X frame brace that I had lying around. Used wet grinding to prevent CF dust from flying around, which worked quite well.

After flying and crashing very hard a lot of times, I can confirm that these long finger-like motor prototectors have saved my motor bells every time.

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I've tested top-mounting of the battery and can say that I feel a tiny little difference in feel. But, it is somehow also a little more challenging to pull out of difficult dives with the battery on top. So since I find it slightly easier to fly with the lipo bottom-mounted, that's where I'm keeping it. I'.ve also tested the GF2512 props around this time and liked the smooth and precise control, but decided to leave the GF2512's for my toothpick and rather stick to heavier-pitch props on this build. The 1206 motors happen to have enough torque to strip the GF2512 blades clean off when bouncing off of steel poles.

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(Yes, I strapped a piece of packaging foam to the top of the lipo to protect it...lipos are scarce these days.)



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KristofFPV   Mar 31, 2022  

Interesting build. What's your empty weight and starting weight with a 4S 450mAh battery?

yohfpv   Apr 01, 2022 

Hey KristofFPV, the weight of the quad itself is 96g with a single XT30 pigtail and 98g with a double XT30 like I'm flying to b able to use 2S lipos. My AUW with 2x 450MAH 2S lipos comes to 150g exactly.

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