Why do the tail feathers on drones appear so different than the standard horizontal and vertical stabilizers on normal airplanes ?
I believe it is done to reduce weight. Instead of three control surfaces (the vertical tail fin and two horizontal elevators) you have only two control surfaces. It requires a more complex control system, but the drones are fly by wire anyway.
It’s also done to make the aircraft less visible to RADAR. Stealth aircraft also use V-tails for the same reason, to avoid having a vertical surface. It’s better to reflect the RADAR signals down at the ground (ETA - or up into the air, in the case of an inverted V) than back towards the RADAR receiver.
I’ve heard that the inverted V common on drones is better for turning than the right-side-up V typically used on aircraft. Maybe one of our pilot dopers can give a better comment on that though.
Excuse my ignorance but don’t “regular” airplanes and drones have very different performance requirements? I thought an airplane was intended to carry a heavy load for a relatively short time, while a drone needs to keep a relatively light load aloft for a very long time.
Sorry if that’s too much of a hijack.
V-tails have somewhat of a bad reputation amongst civil aviation. Regardless of how deserved it is technically they’re not considered desirable. As already said they require a complex control system, and when it has to be analog (i.e. cables not fly-by-wire) this is **highly **undesirable. They also put more stress on the fuselage when turning. All this for little advantage vs. a conventional tail & rudder.
Also, the inverted-V design requires extra tall landing gear, which is, again, a big liability (extra weight, complexity, can be very unsafe etc.).
Ah, this isn’t really a factor here. All aircraft are designed based on their specific needs. A V-tail is just one design element and it isn’t really specific to long duration or payload.
Stealth, weight saving, storage, shipping, assembly, weapons firing consideration, and who ever won the contract had a design engineer who liked them. ???
YMMV
I am not sure of all the reasons drones have tails like that but there is a reason airplanes do not. Tall landing gear like that is undesirable from a pilot’s perspective because it is fairly fragile and not well-suited to less than perfect landing surfaces. It also makes it difficult to judge landing height. The tail on the drone is also dangerously close to the ground with doesn’t allow much room for error in a landing flare. Human pilots would scrape it against the ground during a landing flare any time they flared too much. Drones are lighter and slower than most planes and their flight is precisely controlled by computers so presumably they don’t have to worry about these risks as much.
I read somewhere it was to stop the prop from hitting the ground during take off and landing.
After all they could have the feathers pointing up.
I’ve heard that too. The Predator is the latest in a line of evolution that started in 1986 with a UAV named Amber. I’ve read it had the inverted V tail simply to protect the prop.
An inverted V does provide proverse yaw as opposed to the standard V’s adverse yaw. In short, the standard V fights you in a turn while the inverted V helps you. That may have something to do with the reason the kept it around.