Linked Questions

6 votes
5 answers
2k views

What determines maximum speed of a propeller aircraft - Thrust or Power?

I'm reviewing training materials1 for straight and level flight. The content focuses on drag types and explains that the required thrust curve is equivalent to the total drag curve. It then introduces ...
Crabsticks's user avatar
2 votes
1 answer
119 views

What is the range of ratios between optimal propeller efficiency and true propeller efficiency?

In https://aviation.stackexchange.com/a/15383/20394, the optimal prop efficiency is given as: $$\eta^{opt}_{Prop} = \frac{1 - \frac{\Delta v\cdot \left({v_{\infty} + \frac{\Delta v}{2}}\right)}{d_P^2\...
Kenn Sebesta's user avatar
  • 4,964
0 votes
1 answer
2k views

static thrust vs. prop RPM data?

edit: question was too long, and is actually simple, so I removed unneccesary description Background: There are many questions here about: propeller efficiency changes to thrust when it is dynamic ...
ivanantuns's user avatar
16 votes
5 answers
4k views

Why is thrust inverse to speed in piston engines?

It is said that piston engines have constant power output, and thus their thrust is inverse to speed (e.g. here), while turbines have relatively constant thrust. I'm looking for an intuitive ...
ciamej's user avatar
  • 293
4 votes
1 answer
455 views

Matching the Drag Equation to Real Airplane Data

I am trying to compute airplane performance for a piston-driven airplane with constant speed prop using the standard equations for Lift, Thrust and Drag. I have found that there are a couple of useful ...
Phil Crowther's user avatar
10 votes
7 answers
3k views

Explained intuitively, why does aspect ratio affect induced drag?

Over the last few hours, I've been trying to intuitively understand induced drag, and how aspect ratio affects it. I already know the equations, but while they explain the relationship, they do not ...
Xelphonential's user avatar
2 votes
2 answers
449 views

How much is a swashplate system more energy efficient than a fixed blade system for the same load

When reading about the lifting capacity of swashplates (as found in helicopters) vs fixed blade systems (as found in e.g. DJI drones), I read a lot of comments about the fact that the bigger rotors of ...
Arie's user avatar
  • 117
3 votes
4 answers
2k views

Is there any theoretical problem powering the fan with an electric motor [duplicate]

A question that I have been wondering about lately is whether it would be possible to power the fan in a modern hi-bypass turbofan with an electric motor and achieve performance comparable to the ...
erikkallen's user avatar
0 votes
2 answers
813 views

Would large, low aspect ratio fan/propeller blades be more efficient? Why not?

With reference to this answer We read in the above that accelerating a larger mass of air by a smaller amount is (theoretically) more efficient. This is an advantage of a larger propeller than is ...
Abdullah's user avatar
  • 3,524
1 vote
1 answer
176 views

Is flow attached at fixed propeller blade at every RPM / speed conditions?

Propeller blade AoA depends on tangential veloctiy caused by rotation and forward speed "head wind". If propeller has fixed pitch is flow attached on blade at every RPM / speed conditions? ...
user avatar
1 vote
1 answer
88 views

What are some first-order drag approximations for airframe/propwash interactions?

What are some first-order drag approximations for airframe/propwash interactions, both for dynamic flight and for static thrust, in a traditional tractor configuration?
Kenn Sebesta's user avatar
  • 4,964
10 votes
4 answers
2k views

How can best glide speed be lower than best rate of climb speed?

I was looking up V-speeds for C172. I don't have easy access to an official copy of the POH, but online I found: $V_y$, best rate of climb speed (at sea level): 76 KIAS (p22) $V_{glide}$, maximum ...
Jan Hudec's user avatar
  • 56.2k
1 vote
1 answer
396 views

How energy efficient is an aircraft take off?

How much work is generally done by an aircraft (e.g. B737NG) in order to reach V_rotate, and how does this compare to the energy content of the fuel that is used?
JNld's user avatar
  • 11
1 vote
1 answer
3k views

What is the Efficiency of Cessna-150's Propeller?

From that Cessna-150's data, it used Continental 0-200-A 100 HP (75 kW) at 2,750 RPM and with Fixed Pitch propeller with its diameter=69 inches. If power is delivered maximum to the propeller (through ...
AirCraft Lover's user avatar
8 votes
3 answers
5k views

What is compressibility drag?

I don't mean wave drag here. What is compressibility drag, which is understood to be a form of miscellaneous drag?
Guha.Gubin's user avatar

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