5 Tips for Becoming a Long-Range FPV Master
I want to paint you a picture. You’re out 2 miles and up 4000 vertical feet finally about to hit that distant cliffside you’ve been dreaming about. Your quad is flying on rails and you know the shot is going to be “fire” because you just mounted up your new Hero 8. You start dropping into a killer chute dive. Dodging right, shooting left. 50 mph. Now 70 mph! The screen instantly turns to static! You peg the throttle, hoping you get your video signal back! Three heart beats pass and your video is back, but your quad is tumbling and you can’t recover. Everything seems to move in slow motion as you frantically toggle your arm switch and catch the last few transmitted frames of your drone just before it plows into a rock face at 80 mph. Your goggle screens display nothing but static.
Losing a drone just flat out sucks. Especially if it goes down in an area where you can’t recover it. Good news is that there are many things you can do to minimize the chance of losing a drone the next time you’re putting long range miles on your props. Here are my 5 tips for becoming a long range FPV master:
#1: The build and why your antennas are top priority
There are countless ways to build a long-range rig. Maybe you choose big props and low KV motors to float along at maximum efficiency. Or maybe you build a speed demon that screams down chutes with punch-out power overkill. Regardless of the build, nothing limits its ability more than poorly performing antennas. When it comes to antenna mounting, a vertically mounted antenna is king. Best practice is to mount the RX antenna vertically, tilted back about 30 to 40 degrees, and as high up as possible. Same goes for the video antenna. As long as your antennas are the highest most visible thing on the drone, your risk of failsafe and glitchy video several miles out drastically decreases and allows you to fly without the body of the drone blocking your signal. So, pony up, buy quality antennas, and mount them properly because no amount of VTX power will make up for poorly placed, out of tune, or damaged antennas.
#2: Calibrate your current meter and use the 60/40 rule
So, what flight strategy will get you to reach your max range? Should you fly faster or slower? 3 minutes out and 3 minutes back? Maybe you’ve just been flying out until you hit 3.8 volts on each cell and then turn around? The key to unlocking your drone’s maximum range is in your current meter – get that current meter calibrated!
A common practice is to land your quad before it falls out the air from a dead battery. This means you only use about 80% of your battery’s capacity. (1500 mah = 1200 mah usable, 2200 mah = 1800 mah usable etc.) To get the most out of your battery when going for distance, set your throttle such that your drone is drawing a constant number of amps. Whether you’ve chosen 8, 12, or 20 amps to cruise at, you’re going to want to keep it consistent. Set that throttle, and leave it! Adjust your pitch angle to control your elevation if you’re climbing a mountain.
Now, if you’re just traveling flat, the rule of thumb is to use half your battery out, and half back. So if you’re flying a 1500 mah pack (remember that gives you 1200 mah usable), use 600 mah out and 600 mah back. But what if your flying up a mountain? You’re probably going to lower your throttle on the dive down, increasing efficiency and flying faster which means you may adopt a 60/40 rule (720 mah out, 480 mah back). For really steep mountains you might choose 70/30 rule (840 mah out, 360 back). And if you start from the top of a mountain flying down hill, you can use a 40/60 rule to make sure you get back.
#3: Run the numbers to get your max range – flight time is irrelevant
Let’s use a simple equation to see why flight time alone is not a useful metric for us. This will help determine what our drone’s max range is. We might even see how to optimize a drone specifically for long range. Let’s simplify things and look at the variables that determine our range. Battery size (AmpHour in our equation), flight speed (miles/hour), and current draw (Amps). *Remember step #2 where we chose a current draw to maintain? If Amp draw is constant, this is our equation:
Max distance = (usable battery AmpHours)*(flight speed mph) / (Current draw in Amps)
Boom, it’s that easy!
Let’s give it a try. If we choose to pull 8 Amps, using a 2200 mah (1.76 usable AmpHours), and we either measure by GPS (or rough guess) that at 8 Amps we are moving at around 30 mph.
(1.76 AmpHours)*(30 mph) / (8 Amps) = 6.6 miles of range! (and a 13 minute flight)
13 minute flight
How about we choose 10 amps and we’re moving at 37 mph.
(1.76 AmpHours)*(37 mph) / (10 amps) = 6.6 miles of range!
10.5 minute flight
Maybe we build a super low drag frame and fly fast at 12 amps, assuming 45 mph.
(1.76 AmpHours)*(45 mph) / (12 Amps) = 6.6 miles of range!
8.8 minute flight
You may notice that if we chose a setup based only on flight time alone we would choose the first one because obviously 13 minutes is better than 10.5 minutes or 8.8 minutes! When it comes to max range, all these drones are actually the same. However, if you’re anything like me, bombing chutes at 45 mph is going to be waaaaaay more fun than just floating along at 30mph!
So how do we maximize a drones range? The answer is to minimize current draw and maximize flight speed while hauling the biggest battery possible. And it’s a balance. We might try thicker skinny arms and a slim body to lower drag which will directly increase flight speed. We could increase our cell count and decrease our motor KV, which reduces current draw by increasing voltage and motor efficiency. We could choose a lower “C” rating battery to get more capacity in a lighter, smaller pack and then fly steadily without pulling too much current from the pack. Here are some of the numbers that I’ve used to maximize my range using a Gen3 Ruxus frame, a 5s 3000mah pack, 7″ props, and 1600kv motors:
(2.4 AH)*(40 mph)/12 Amps = 8 miles
And it works! I plotted an 8 mile route in Google Maps, took off holding my drone at a 12 Amp current draw and landed home after completing 8 miles and having used 80% of my battery! So, run the numbers to find your range and then trust your gear to make it that far and back.
#4: Plan your route
The first thing you should do before plugging-in is to take a good look at the route you’re going to be flying. Make a mental note of which parts of the mountain are visible. Are there any disguised ridges that you might duck behind, or areas with sparse vegetation invisible to an FPV cam? What about a false summit that might lure you over the peak and out of range? Which areas are non-recoverable and which areas are accessible to fetch a downed drone?
There is also a good chance that many things will be unrecognizable from the air so you will want a solid landmark next to you to find on your way home. Choose landmarks to fly to as if they were checkpoints to keep you from getting lost or wandering astray. Your mental notes on the line to take might include something like: up to the summit, right turn down the ridgeline, fly straight to the third chute over, drop in at the fractured bolder, fly high at the crooked pine to avoid the brush, dive back in at the waterfall, pull up when the chute forks, fly toward the grove of aspen on the other side of the valley, and then back to base. With this method it will be much harder to get lost on the route home.
#5: Use a spotter
This is by far the best advice I can give. A good spotter is worth their weight in solid-gold quad parts. I’ve been flying long range for several years, but I have yet to lose a drone to the mountains due to having a trusted spotter with me when I am exploring new territory. A pilot can only focus on so many things at once and there are many things that can’t be checked from the pilot’s seat. A good spotter will jump in and out of their goggles with information such as, “you can ride this ridge till the shadow hits it”, “you have full line of sight down this entire cliff until the tree line”, “you’re about to pass behind a tree, your video will get fuzzy but will come right back”. A pilot might be focused more on not crashing in a dive than checking his telemetry and the spotter might say: “Your RSSI here is dropping fast in this chute”. My spotter has even changed my goggle battery mid-flight when I was too far out to make it back in time. Besides, flying with a good buddy is always 10 times more fun!
So get out there, max out the miles on your long-range rig, and explore what’s around you with the confidence of a long-range FPV master!
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