As Durex has skilfully avoided telling us for years, size matters.
When I got into FPV, the ‘How big’ question was a simple one for me: Exactly five inches.
That was because I had carefully considered all the benefits and drawbacks of this size, and drawn up a 100 point table of the pros and cons of different frames. Except that’s all bollocks, and the real reason was because back in 2014, 5 inch was pretty much the only size worth bothering with.
Fast forward to 2018 and almost everything except Joshua Bardwell’s YouTube viewings had got smaller. Plus, micro cameras now had a picture as good as a kosher 28x28mm job. All that was needed was something to put them on.
Suddenly, the three inch frame made a lot of sense.
The reduced weight lended itself to whipping through urban obstacles like spaghetti round a fork. And, with the UK government due to slap a new requirement on >250g whirlybirds, a 3 inch had significantly more chance of getting its weight down to screw-registration grade.
I mulled these things over, then threw some money at someone. A few days later, a beige, mandarin-covered box with dubious taxation info arrived on my doorstep. It contained an XJB 145, a pnp three inch ship.
A few things had to be sorted out first, of course. A cheap-as-chips XM+ was shoved atop the central stack, because it looked darn slick there. And also because there was precisely nowhere else to put it. I bought some Graphene 850mahs and, seventy quid lighter, realised I’d need to kit them out with xt30 connectors. Another ten quid spent and some solder-induced burn marks to the crotch later, I had joined the 3 inch revolution.
Going from 5 inch to 3 feels light. Like riding a motorbike after a few years driving a Fiesta with a boot full of breeze blocks, perhaps. I slowed down the rates, but she really wanted to flip and roll. I did some playground freestyle. It was fun.
In car parks, she really came into her own. Tight turns weren’t just possible, but embraced with all four carbon arms. Loops around support beams were done with relish. The lightness really does give you confidence to do more and more.
Until you reach the stage where you realise what a three inch simply isn’t designed for.
Sure, you can cram in a lot of modern kit, but each step is laboured. Clover leaf antennas? Pain in the arse. GPS? Fine, if you don’t mind it being more exposed than Le Drib’s eyebrows. Going long range? Not without punishment. Fitting a Nano crossfire RX may not be a problem, but trying to accommodate a 900 MHz bullwhip is like trying to stick a 50 foot flagpole out your sunroof. And unlike five inch, there’s no swapping out the arms to make a true ‘to the next country and back’ ship.
A particularly sore point with some 3 inch frames is camera size. The M12 lens of the Ratel or the Toothless micro simply won’t fit. Many frames will limit you to smaller-lensed offerings like the Foxeer Falkor and Razer. If you went into 3 inch territory expecting everything to accommodate Hollywood equipment, this leaves a sour taste.
And as powerful as they are, the wind loves them. When gusts get above twenty mph, fast forward flight feels like it’s taking place on the back of a charging bull. It’s not that the motors can’t take the strain, or that the software can’t cope. Simple physics dictates that something half the weight of a five inch will get tossed around twice as much.
Speaking of physics, 3 inchers are not terrible at crashing. In the two years I’ve had my HGL145, I’ve unexpectedly mated it with trees, concrete, brickwork and small children. In all cases, the frame was either unscathed or escaped with minor superficial damage.
But my five inch, subjected to the same wayward doinks, handled this punishment just as well. It also flies for about a minute longer, thanks to significantly larger (read: more efficient) props. And if I want to fly it to Vladivostok, I can fit a Crossfire system to the top plate with the sort of effort that Joshua Bardwell uses to select a good catchphrase.
I’m not saying 3 inch platforms aren’t for anyone. If your main haunt is car parks or urban bandos, you’ll appreciate the ballerina-like manoeuvrability. As a cinewhoop, it’ll accommodate any filming equipment short of a 35mm reel, yet it’s still light and small enough to avoid scaring anyone not called Karen. And if a weighing scale-wielding PC Plod should ever tap your shoulder, then they’re the largest size you can get below 250g without resorting to anorexic frame design.
There’s a reason why every class of frame exists, and the three inch is no exception. Perhaps the reduced red tape comes to mind. Perhaps freestyling around the playground like a bonkers horsefly is your thing. Or perhaps, with prop-guards, you fancy filming Downton Abbey at 75mph.
But perhaps, like me, you just want to fly anywhere and everywhere, with any payload, in whatever wind. And in that case, five inch will do you proud.
Size really does matter, then.