29
votes
Accepted
How can best glide speed be lower than best rate of climb speed?
The best glide speed is the speed where tangent line from the origin (zero horizontal and vertical speed) touches power curve (for unpowered airplane).
Best rate of the climb is the highest point of ...
- 2,766
25
votes
Accepted
What is "Bird Strike Speed"?
Aircraft structures are required to withstand the structural damage caused by birdstrike. According to 14 CFR 25.571 - Damage - tolerance and fatigue evaluation of structure:
(e)Damage-tolerance (...
- 101k
19
votes
Accepted
What if you have a double-engine failure after V1 but before VR?
The Airbus A320 FCTM (Flight Crew Training Manual) does not describe any procedure for rejecting a takeoff after reaching V1:
The decision to reject the takeoff is the responsibility of the Captain ...
- 58.3k
15
votes
Accepted
How can V1 and VR (rotate) speeds be calculated?
There is no general equation/function that you can use to calculate V1/Vr... the manufacturer test out the aircraft's performance during certification, and you then compare your current aircraft and ...
- 4,624
15
votes
Has the "Foote takeoff" technique really existed, and how did it work?
At the time of the Comet disasters, Vr did not exist. The standard takeoff technique was what was used on all previous airplanes - line up, release the brakes, apply full power (derated thrust did not ...
- 4,624
15
votes
Accepted
How can an aircraft’s maximum design operating speed be greater than its never-exceed speed?
Maximum design operating speed means "we calculated the aircraft will break apart at that speed". It's obviously higher than the never-exceed speed, which means "you can safely operate the aircraft up ...
- 3,000
14
votes
Why is ditching speed higher than stalling speed?
As far as I'm aware - and maybe a seaplane pilot could give a better answer - one of the big issues with ditching is judging your height above the water. If you stall it in, you might get it wrong and ...
- 72k
13
votes
Accepted
When does the overspeed alarm goes off in a plane?
The overspeed goes off when either the indicated airspeed exceeds that limit or the mach speed exceeds the mach limit. At least that's how it worked on 747-100/200 aircraft.
The 350 knot figure for ...
- 39.2k
13
votes
Accepted
Why would one want to slow to V2 following an engine failure during takeoff?
Simply put, V2 is the speed that guarantees the best angle of climb on one engine. Any slower or faster increases the risk of hitting an obstacle.
Drag
There are 2 main categories of drag - induced ...
- 14.6k
12
votes
Accepted
Why is ditching speed higher than stalling speed?
This is somewhat restated and overlaps the other postings. Here are my thoughts on this:
The ditching speed is to provide a safe approach speed. Depending upon the seas, you may not have the ability ...
- 17.8k
12
votes
How can an aircraft’s maximum design operating speed be greater than its never-exceed speed?
VDO is the maximum speed, demonstrated in testing, that the structure is designed to handle (usually for flutter).
VNE is an operating limitation for the pilot to observe that includes a bit of ...
- 136k
9
votes
Why is the takeoff decision point based only on speed and not time or distance?
Some operations, including the USAF, use an acceleration check speed at a given distance (usually 1,000-2,000'). Data is derived from normal acceleration data gathered during performance testing. ...
- 430
9
votes
Do manufactures list the maximum speed of an aircraft based on its theoretical maximum speed or dive speed?
The 365 knots listed in that brochure is (as noted in the text) the maximum cruise speed. That is the maximum speed at which the aircraft can be expected to operate under normal circumstances in level ...
- 37k
9
votes
Accepted
Do manufactures list the maximum speed of an aircraft based on its theoretical maximum speed or dive speed?
The maximum cruise speed from the brochure is a True Airspeed value and is based on the highest TAS achieved with the engines operating at the maximum cruise power rating specified by the engine ...
- 136k
9
votes
Why would I want to lower the stall speed?
Don't I want to have a higher stall speed so I could be far from stalling?
Unfortunately this is incorrect. Aerodynamic stalls happen when an aircraft’s airspeed is at or below the aircraft’s stall ...
- 16.6k
9
votes
Accepted
When is Vmo/Mmo applicable?
The limitation is always the lower one of the two, meaning your actual IAS must be below Vmo and your actual Mach must be below Mmo.
Let us consider this case: you accelerate all the way to Vmo and ...
- 58.3k
8
votes
Does MMO (limiting Mach number) assume any maneuvering limits?
The problem is that in a deliberately entered spiral dive it is very difficult to keep things in check. In an idle descent, pitch is your only speed control (well... really, in the end, pitch is your ...
- 136k
8
votes
Is there an aircraft that can go supersonic at sea level without using afterburner?
According to Wikipedia, the BAC TSR-2 was capable of supercruise (no reheat) at Mach 1.1 at 200 feet (~60 m) altitude. The TSR-2 first flew in 1964. The English Electric Lightning had demonstrated ...
- 17.3k
8
votes
Accepted
What does it mean to move a single flight control to its full deflection?
Yes, that is correct. Moving any control surface until you hit the stops is considered "full deflection". For the purpose of maneuvering speed, this is the speed at which any single control surface ...
- 36.2k
8
votes
How does an inoperative Anti-Skid affect V speeds?
When you say it affects V speeds, I assume you mean V1 (and possibly VR), but not V2. V1 is usually calculated from the balanced field length, which is where accelerate-stop-distance and accelerate-go-...
- 58.3k
7
votes
Why is ditching speed higher than stalling speed?
I tried to put this in as a comment to @Pondlife's answer, but ran out of room, thus this answer is an amplification of what he said. He is correct. Judging height above the water is a challenge, ...
- 39.2k
7
votes
Accepted
What's the difference of Vs from Vs0 or Vs1?
VS is the generic term. However, since stall speed varies depending upon how the aircraft is configured (in particular the flaps), we break that down into VS0 for landing config and VS1 for cruise ...
- 27.9k
7
votes
Helicopter V speeds explanation
Vx is the best angle of climb speed, with all engines operating. Helicopters can climb vertically in some situations, in which case their airspeed is zero, so Vx is zero. Vx increases above zero for ...
- 18.2k
6
votes
Accepted
Why does V1 increase with weight?
Other than being controlled by Take-Off Run/Distance Available (TORA/TODA) or Accelerate Stop Distance Available (ASDA), all field limits, maximum $V_1$ is also controlled by $V_R$ (Speed for rotation)...
- 3,030
6
votes
Why is the V1-speed callout automated in modern commercial aircraft while VR is not?
from my experience (A310, A320 family, A340), V1 and VR speeds are often very close together, sometimes they even are the same.
The automatic callout system can only output one signal at a time; ...
- 763
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