For Questions That Don't Merit Their Own Thread

[Rutabaga22]

Would it be possible for an animal (Imagine something bat-like) to have finger like bones in it's wings with webbing that could act as a control surface for better control?

[monophonic]

9 hours ago, Rutabaga22 said:

Would it be possible for an animal (Imagine something bat-like) to have finger like bones in it's wings with webbing that could act as a control surface for better control?

You mean... like a bat?

https://askabiologist.asu.edu/human-bird-and-bat-bone-comparison

[DDE]

1 hour ago, monophonic said:

You mean... like a bat?

https://askabiologist.asu.edu/human-bird-and-bat-bone-comparison

I think the key question there is whether these phalanges can be... actuated.

[JoeSchmuckatelli]

4 hours ago, DDE said:

I think the key question there is whether these phalanges can be... actuated.

They do - for fine control. 

Unless you mean https://www.google.com/search?q=vampire+flip+off&oq=vampire+flip+off&aqs=chrome..69i57j33i160l2j33i299l2.7344j1j4&client=ms-android-samsung-ss&sourceid=chrome-mobile&ie=UTF-8#imgrc=o1k-uz0few3a8M

 

[kerbiloid]

Vampires do this daily nightly.

[Rutabaga22]

11 hours ago, DDE said:

I think the key question there is whether these phalanges can be... actuated.

 

13 hours ago, monophonic said:

You mean... like a bat?

https://askabiologist.asu.edu/human-bird-and-bat-bone-comparison

I mean something like this

[JoeSchmuckatelli]

1 hour ago, Rutabaga22 said:

something like this

They already do.  All the 'fingers' can move a little bit for fine control 

Having the wing stretched by fingers gives bats a high morphing ability, i.e. the ability to change the shape of the wing (Figure 1H). The fingers can spread and bend to different degrees, changing the wing area by stretching the membrane or controlling the camber of the wing and as a consequence the lift coefficient of the wing

https://www.sciencedirect.com/science/article/pii/S0960982215004157

Also - 

 

 

Watch how the actual bat's phalanges move compared to the robot 

Edited October 4, 2022 by JoeSchmuckatelli

[Rutabaga22]

Why is the centaur used so much in spaceflight? When can I expected the Starship-centaur

Edited October 4, 2022 by Rutabaga22

[DDE]

9 minutes ago, Rutabaga22 said:

Why is the centaur used so much in spaceflight? When can I expected the Starship-centaur

RL-10 is good, baloon tanks are light. Why mess with perfection? And all things considered, your question might not be too far out there.

[Rutabaga22]

1 minute ago, DDE said:

And all things considered, your question might not be too far out there.

Are you suggesting that starship-centaur is valid?

[DDE]

2 minutes ago, Rutabaga22 said:

Are you suggesting that starship-centaur is valid?

Centaur-Anything is valid with a proper "corset". After all, all the design work on Shuttle-Centaur was complete.

[Rutabaga22]

1 minute ago, DDE said:

Centaur-Anything is valid with a proper "corset". After all, all the design work on Shuttle-Centaur was complete.

The shuttle-centaur has me laughing my SAS off. The fact that the made an entire system to deploy centaur from shuttle is wild.

[LHACK4142]

So this might be a bit of a dumb question but here goes: What if you put vertical stabilisers on a long boom behind a flying wing?  From what I've read, a big problem with flying wings is that putting vertical stabilisers on them can very much reduce or even negate the decrease in drag (not sure why), while being ineffective because they're too close to the CoM. So, what if you put them on a long boom so that the wing and stabilisers don't interfere with each other much and almost act as seperate objects?

[Gargamel]

13 hours ago, LHACK4142 said:

So this might be a bit of a dumb question but here goes: What if you put vertical stabilisers on a long boom behind a flying wing?  From what I've read, a big problem with flying wings is that putting vertical stabilisers on them can very much reduce or even negate the decrease in drag (not sure why), while being ineffective because they're too close to the CoM. So, what if you put them on a long boom so that the wing and stabilisers don't interfere with each other much and almost act as seperate objects?

Then…. You have a regular plane, but without elevators.   Might as well add elevators for more stability while you can, and you have a regular plane.  

[Entropian]

14 hours ago, LHACK4142 said:

So this might be a bit of a dumb question but here goes: What if you put vertical stabilisers on a long boom behind a flying wing?  From what I've read, a big problem with flying wings is that putting vertical stabilisers on them can very much reduce or even negate the decrease in drag (not sure why), while being ineffective because they're too close to the CoM. So, what if you put them on a long boom so that the wing and stabilisers don't interfere with each other much and almost act as seperate objects?

From my very basic knowledge of aerodynamics I expect that the vertical stabilizers would still induce wing vortices(?) which will increase the drag.  I'm by no means very knowledgeable about aerodynamics so I could be way off here.  @mikegarrison is probably able to answer this question with detail and such.

[sevenperforce]

14 hours ago, LHACK4142 said:

From what I've read, a big problem with flying wings is that putting vertical stabilisers on them can very much reduce or even negate the decrease in drag (not sure why), while being ineffective because they're too close to the CoM.

It's not (particularly) a problem of interaction between the stabilizers and the wing surface, although that can come into play. Rather, it's more an instance of one thing leading to the other. Because vertical stabilizers are so close to the center of mass, they don't have a very good control moment over yaw. Because they don't have a very good control moment, they must be very large in order to effectively damp yaw. Because they are much larger than you would need on a conventional aircraft, they create much more drag (all by themselves) than the vertical stabilizers of a conventional aircraft.

14 hours ago, LHACK4142 said:

What if you put vertical stabilisers on a long boom behind a flying wing?

You can.

But at this point you basically just have an ordinary plane.

[mikegarrison]

Vertical stabilizers and rudders are actually sized by engine-out conditions (on most multi-engine airplanes). The asymmetric thrust is a bigger deal than basic yaw stability and control.

Anyway, as @sevenperforce just said, it's mainly about lever arms. The farther away from the aerodynamic center for yaw, the smaller you can make them and still get the same control. Vertical stabilizers don't usually have a significant amount of steady-state lift-induced drag (because ideally they are trimmed to a zero-lift condition), but they still have form drag and friction drag and wave drag. So the smaller the better, usually.

[magnemoe]

 

3 hours ago, sevenperforce said:

It's not (particularly) a problem of interaction between the stabilizers and the wing surface, although that can come into play. Rather, it's more an instance of one thing leading to the other. Because vertical stabilizers are so close to the center of mass, they don't have a very good control moment over yaw. Because they don't have a very good control moment, they must be very large in order to effectively damp yaw. Because they are much larger than you would need on a conventional aircraft, they create much more drag (all by themselves) than the vertical stabilizers of a conventional aircraft.

You can.

But at this point you basically just have an ordinary plane.

And one who look dorky, unless the Lighting who is kind of similar design but cool. 
Yes the Lighting had inter coolers and stuff who made the engine pods oversize so just stretch for aerodynamic and put an tail plane between them as the Lighting did not need an large fuselage. 

24 minutes ago, mikegarrison said:

Vertical stabilizers and rudders are actually sized by engine-out conditions (on most multi-engine airplanes). The asymmetric thrust is a bigger deal than basic yaw stability and control.

Anyway, as @sevenperforce just said, it's mainly about lever arms. The farther away from the aerodynamic center for yaw, the smaller you can make them and still get the same control. Vertical stabilizers don't usually have a significant amount of steady-state lift-induced drag (because ideally they are trimmed to a zero-lift condition), but they still have form drag and friction drag and wave drag. So the smaller the better, usually.

This is very critical for two engine passenger planes, if you get an engine out just at takeoff you get an huge asymmetric trust and the speed is low so the tail don't have much authority so you need to make it large. Makes me wonder if some will come up with tricks for this? longer tail planes is one thing who is used, not much more drag, but heavier and the forward part has less effect. 
Thinking about stuff like fold out tail flaps or grind fins for takeoff. 

Edited October 5, 2022 by magnemoe

[kerbiloid]

Can its fin pass through the hangar doors? Maybe they just sawed it off?

[Rutabaga22]

19 hours ago, LHACK4142 said:

So this might be a bit of a dumb question but here goes: What if you put vertical stabilisers on a long boom behind a flying wing?  From what I've read, a big problem with flying wings is that putting vertical stabilisers on them can very much reduce or even negate the decrease in drag (not sure why), while being ineffective because they're too close to the CoM. So, what if you put them on a long boom so that the wing and stabilisers don't interfere with each other much and almost act as seperate objects?

Couldn't you use differential thrust for horizontal stabilization? 

[mikegarrison]

32 minutes ago, kerbiloid said:

Can its fin pass through the hangar doors? Maybe they just sawed it off?

That was actually an important design consideration for the https://en.wikipedia.org/wiki/Lockheed_Constellation, which was designed with a triple stabilizer because they wanted to make sure it would fit into the hangers of the primary customer. A single vertical stabilizer would have been too tall and would have required new hangers.

16 minutes ago, Rutabaga22 said:

Couldn't you use differential thrust for horizontal stabilization? 

Not if you lose an engine.

[sevenperforce]

12 minutes ago, Rutabaga22 said:

Couldn't you use differential thrust for horizontal stabilization? 

That's how most of the flying wings I've built in KSP fly, but in real life you have to be able to have full control in an engine-out scenario, which is where you run into problems.

A more workable solution is differential drag via split ailerons. Rather than just having a single aileron control surface at the tip of each wing, you have two overlapping ones, and so you can either deflect them up or down in a pair (to control roll) or you can deflect them in opposite directions to induce drag. By making the tip of one wing more draggy than the other, you turn the plane toward that wing in the yaw axis.

[kerbiloid]

14 minutes ago, mikegarrison said:

That was actually an important design consideration for the https://en.wikipedia.org/wiki/Lockheed_Constellation, which was designed with a triple stabilizer because they wanted to make sure it would fit into the hangers of the primary customer. A single vertical stabilizer would have been too tall and would have required new hangers.

Same problem was actual for Energy when using the N1 manufacturing facilities.

They say, its diameter was reduced down to 7.75 m to match the N-1 utilities, and the doors were another limiting factor.

[Rutabaga22]

I need spacecraft lifetimes on bodies other than earth for something I am doing with a friend, specifically bodies with an atmosphere. even more specifically venu, but other ones would be nice.

Edited October 5, 2022 by Rutabaga22

[sevenperforce]

19 minutes ago, Rutabaga22 said:

I need spacecraft lifetimes on bodies other than earth for something I am doing with a friend, specifically bodies with an atmosphere. even more specifically venu, but other ones would be nice.

Wikipedia is your friend.