Can anyone in aerospace engineering explain to me the benefits

Are those rear fins even airfoils?

>>8991022
It's so it can fly really low to the ground and chop the heads off of terrorists

>>8991022
put on your thinking cap and let me ask you what the difference is between the drone in your picture and an airplane in terms of what is where on the craft

Airplanes are fucking gay and so is you

Not in aero but pulled some basic shit from a reddit post asking the same thing:

>There isn't a lot of benefit of an inverted V-tail over a conventional V-tail (i.e. down versus up). For the most part they perform the same. Some amount of it is likely just a stylistic choice as much as anything.
One advantage that the inverted V-tail has is for planes that are hand launched. In many cases UAVs have opted for a single propeller at the rear of the craft (this simplifies some of the aerodynamics). The propeller needs to not hit the guy launching (i.e. throwing) the plane. Having the tail inverted helps protect that guy from the propeller—they get hit by the tail instead. The same is true when landing—the tail hits the ground before the rest of the plane. The tail can be made to be strong enough to take the impact, thereby saving the expensive propeller.
As for the dynamics of the plane, an inverted V-tail helps the plane when it turns. Inverting the V-tail makes it so that you don't need the ailerons (control surfaces on the wings used for controlling roll) as much.
Also, when a plane is landing with a crosswind having an inverted V tail can be an advantage. If you're landing on a runway traveling north and there's a crosswind blowing to the east then having a tail in the rear will tend to point (yaw) you towards the west, which is a good thing (or at least better than pointing the other direction). If the tail is pointing predominantly up then it will also make you roll to the right, which isn't good. If the tail is pointing mostly down then you'll roll to the left. If you want to make landing as easy as possible for the plane then pointing the tail down can help. With a manned plane you tend to trust the pilot more.
Inverting the V-tail has the disadvantage of making the landing gear need to be taller.

I'm sure qualified anons could clarify on this.

>>8991022
Buoyancy for front-heavy, light and slow-moving aircraft, you tweed.

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>>8991092
Pretty much right about everything besides the hand launched thing, people always underestimate the size of these things.

>>8991108
Whoa. I have never seen that. Thanks anon!

Because you can use them as aileron.

>>8991108
B-but that has the rear wings pointing up...

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>>8991134
Woops my bad, that was an MQ-9, here is the RQ-1 like the OP.

>>8991022
to take advantage of the change in airflow over the main wing, maybe?

Their int much benefit but, my guess is they did that to make room for components of the prop or guidance systems. But they are anhedral because it helps in stability while turning.

>>8991022
Anyone else get a kind of alien from "Alien" vibe from these things? It's the shape of the nose.

>>8991125
this

don't gotta see shit

fly that fucker into wtc, can't blame nobody but the goddamn robot

man, fuck drones

polite sage

>>8991092
>implying you can hand-launch a predator UAV

I'm pulling this out of my ass here, but by looking at them it seems they were never designed to land (the rear fins prevent it from the image). Maybe it is so that if the drone ever got hacked into it could never land safely and be destroyed if it did (allowing no data to be recovered by the enemy).

>>8991108
I always thought they were bigger...

>>8991022

They probably went with that solution because an issue that they found with a conventional layout, so they were testing and found cracks in the airframe, and said themselves "well now how can we fit this shit without cracking the frame?...Ahh i got it, lets put the fins in this way!....alright just charge the check to the defense department and finish this problem now! We are late to meet the whores that are waiting us next street!"

Engineer's life

>>8991861
You are aware that folding landing gear is a thing right?

>>8991108

Fair point, but I am willing to bet that there are inverted fin nad-launched drones, and that this is what the guy quoted in >>8991092 was referring to.

>>8992232
>nad-launched

Dammit.
"Hand launched."

Also, hoping for a pic to share, I just googled "hand launched drone."

After going several pages deep into images of a lot of different designs, none with pusher-props had inverted fins on the tails, all set the prop above a spar running from the fuselage/wing back to the tail fins. I guess on the pretty sound principle that you actually don't want any part of the drone to hit the guy launching it.

So guy quoted at >>8991092 is likely wrong on that point.

>>8992262
>the prop above a spar running from the fuselage/wing back to the tail fins

Like so.

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>>8992279
>Forgot pic.

I suck at posting today.

>>8991086

Are you suggesting stabilizers on the side of the craft in which the optical devices are mounted?

Crazy!

>>8991022
Aero student here

First let's go over what tails are for:
Stability derivatives of an aircraft are quantities which essentially tell us if the aircraft is statically or dynamically stable. An aircraft with one or more + stability derivatives will diverge from its equilibrium further once perturbed. When designing an aircraft, you want stability derivatives to be typically negative, except for a handful of military cases requiring extremely advanced control software which have positive stability derivatives for manuevrability.

V-tails are typically used to combine the functions of horizontal and vertical stabilizers. They inherently couple yaw and pitching. So long as stability and manuevrability characteristics are okay, there is no advantage to a regular or inverted V-tail from this perspective.

However, depending on the aircraft, inverted V-tails may have advantages such as structural ones or being less affected by the wing wake.

>>8991022
Airplane design changes are limited & constrained by regulations
(Thanks to EU & to the Congress of each country)
So for traditional airplanes there is less freedom to change the design.

Drones are new technology so are less regulated,
so there is more freedom to change the Design of drones.

>>8992376
that doesn't explain why it's done at all, other than "because they can"

>>8992381
In the times before the advent of Modern Computers. All tests were made in Labs, Wind Tunnels with small replicas/models/prototypes. There was no simulation software back then. To Create each replica/models/prototype in real life was time/cost expensive.

Now we have modern softwares that can simulate the aerodynamics for a more variety of design shapes & situations. Thanks to Computers.

We don't need to create hundreds of replicas anymore. We can experiment more crazy design with Virtual models & test them by Computer Simulation.

We then build a replica only for the final prototype.

But all of regulations that limits design creation were created on the previous century, these regulations limits design improvements for traditional airplanes.

Because that the design of commercial airplanes is now a bit stagnating, the good side is that it's stable & safe.

Drones & Top Notch Military Aircrafts Design are more Innovative & improve at faster rates.
>>8992376

>>8991022
So they can stack them upright and not have them wobble.

>>8992402
Not trying to bash you or anything but you're still not giving any advantage of the setup other than "because they can"
Military aircraft being more experimental isn't really what this thread is about

>>8992423
Not him, but assuming a fin costs X dollars, a V fin cost 2X dollars for fins, a standard triple fin version costs 3x.

If, as >>8992402 says, there is no inherent DOWN side, then that alone might be reason enough.

Plus it cuts the points of potential failure in the tail, might all for less maintenance, etc.

>>8992880
I read somewhere a V-tail must be somewhat larger to achieve the same performance as a standard triple fin resulting from projecting said V configuration

>>8991022
so they dont bust the propeller by accident on the ground

>>8992880
wrong the "downside" is that it is critically stable but that is not a problem with regulation control

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>>8991022
>Can anyone in aerospace engineering explain to me the benefits of designing the rear fins on drones to point down like that instead of more traditional rear wing designs that you see on airplanes?
Mainly, it protects the pusher prop. Drones use pusher props more often to keep the sensor ball's view clear, but this introduces a much greater risk of propeller strike during takeoff and landing. Other factors aren't particularly significant. Note he Predator's successor, the MQ-9 Reaper, used a single ventral to protect the prop and an upright V-tail instead of the inverted V used on the Predator (and Gnat and Amber).

If I attach a camera to an RC plane what's the biggest range that can give me a live video feed?

>>8993443
depends on sooo many things that I'm going to answer 80 metres and fly away.

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>>8993443
Range is pretty much set by the budget you have.

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>>8991086
>put on your thinking cap
we don't wear those any more, Grandpa

>>8993443
>If I attach a camera to an RC plane what's the biggest range that can give me a live video feed?

Build a better antenna for a better feed.

>>8993443
A basic setup with a 25 mW, 5.8 GHz VTx and a common RX5808-based video receiver and omni antennas will give you a clear picture out to 100 yards reliably, in lieu of obstructions. A few times further with limited but flyable static. A 200 mW VTx will triple that range, and a directional receiving antenna can give you many times more (assuming the main beam is pointed towards the plane).

>>8993015
>but that is not a problem

Hence, not a "downside."