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Questions tagged [v-speeds]

Questions on the critical speeds of an aircraft guiding elements such as rotation, climb, and maneuvering.

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15 votes
2 answers
9k views

How is minimum runway length related to V1?

1) Is $V_1$ used to determine minimum runway length? How is $V_1$ calculated? 2) If it is used to determine the minimum runway length, and for example we have a runway of 8000 ft and my airplane's ...
camilogv's user avatar
  • 353
10 votes
4 answers
3k 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
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8 votes
6 answers
5k views

What if you have a double-engine failure after V1 but before VR?

Imagine an A320 on the runway, starting its take off roll. The PM calls out "$V_1$". Just a second after $V_1$ is called out, and before $V_R$, you encounter a double-engine failure (an A320 ...
Ishaan Manish's user avatar
20 votes
2 answers
3k views

Why is the takeoff decision point based only on speed and not time or distance?

The go/no go decision on takeoff for airliners is calculated as a V1 speed. The question is, why is there no time or distance for V1 calculated. In other words, if we don't reach V1 in X seconds or by ...
TomMcW's user avatar
  • 28.5k
13 votes
2 answers
31k views

How can V1 and VR (rotate) speeds be calculated?

I want to learn about how can the V1 and VR (rotate) speeds be calculated for take off. And which factors are affecting this calculation? Basically it may depends on the aircraft weight, runway ...
kkakkurt's user avatar
  • 293
7 votes
2 answers
9k views

How to calculate the best glide speed if there is none on the POH?

I am studing the POH of Seneca II and could not find the Best Glide Speed. Where can I get this information from? I thought to multiply Vs clean for 1.4 to get an approximate result but I am not sure ...
Andrea Ghilardi's user avatar
3 votes
4 answers
2k views

Why is best angle/rate of climb indicated in airspeed?

I understand the difference between best angle of climb $V_{x}$ and best rate of climb $V_{y}$. When I take off I would aim to maintain one speed or another depending on what I want. But I don't ...
Hot.PxL's user avatar
  • 517
19 votes
3 answers
13k views

In a 747 is it normal for the Vr (takeoff speed) to vary greatly depending on fuel load and ambient temperature?

I was reading one of the documents linked on this question, particularly I was reading case study number 8 of this particular document. In the conclusion the author notes that the aircraft flight ...
Jae Carr's user avatar
  • 24.2k
12 votes
3 answers
2k views

Why is ditching speed higher than stalling speed?

I was looking for a checklist for the Cessna 182 and I stumbled upon this one. When I looked at the speed-table, I found an interesting entry. It says "Ditching" with a speed of 65 KIAS: Everything I ...
Noah Krasser's user avatar
  • 8,992
11 votes
3 answers
47k views

What are the landing stall speeds of a Cessna 172?

I understood from Why is stall speed listed in a POH? that the Cessna Skyhawk POH lists stall speeds for specific conditions due to a lack of AoA indicator. However, what's unclear to me is what the ...
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11 votes
5 answers
2k views

Why don't Transport Category aircraft have a listed Vy?

I was talking with a pilot about an inability to maintain the targeted climb rate in a particular situation and asked him what the Vy was for the jet. He curtly replied "Vy is only for Part 23 ...
Cody P's user avatar
  • 6,773
8 votes
2 answers
1k views

Does MMO (limiting Mach number) assume any maneuvering limits?

This answer to a question about emergency descents notes: [Y]ou can accelerate descents by banking the aircraft into a turn. This allows you to increase angle of attack, thus increasing drag to ...
feetwet's user avatar
  • 2,274
6 votes
3 answers
2k views

What are the V-Speeds used during a normal takeoff in a multi-engine airplane?

This is what I know: $V_1$ is the takeoff airspeed after which the aircraft must take off, no matter what happens after $V_1$ has been reached. That's the easy part (I think). $V_R$ is the rotation ...
Philippe Leybaert's user avatar
4 votes
2 answers
958 views

Are there any aircraft where minimum-V1 is limited by Vmcg?

V1, unlike all the other Vspeeds, is not rigidly determined by the laws of physics, the aircraft’s specific abilities, and the conditions of the particular takeoff being attempted,1 but is, rather, ...
Vikki's user avatar
  • 28.3k
3 votes
2 answers
3k views

What makes V1 one or two knots less than Vr on this performance table?

(B738 AFM, 0-2000 feet elevation, up to 27°C) Example of V1 and Vr differences. The table shows that the V1 speeds are invariably one or two knots lower than their matching Vr speeds. Given that V1 ...
lemonincider's user avatar
  • 7,565
3 votes
2 answers
886 views

Why is V1 based only on using brakes?

V1 is the speed that an aircraft may abort a takeoff so long as the airspeed is below it, or is committed to flight if it is over that speed. V1 calculations are based only on the brakes (not sure ...
jwzumwalt's user avatar
  • 11.5k
3 votes
2 answers
311 views

Do modern aircraft automatically manage the deceleration to Vref?

Typically in most aircraft, the pilot manually reduces the speed gradually until reaching the landing zone/flare zone. Modern aircraft have FMC. Does the FMC automatically manage the speed gradually ...
user avatar
3 votes
3 answers
3k views

What is physics explanation for minimum sink rate airspeed?

I did some research on Minimum Sink Rate, and saw much information defining it, (such as it is the speed at which the aircraft will remain in the air for the longest time, etc.) and how it is ...
Charles Bretana's user avatar
2 votes
1 answer
2k views

Is reducing V1 a viable option for pilots when the ASDA is shorter than the ASDR?

Let's say you were planning to ferry some passengers and cargo in a jet but after some calculations found out the ASDR (Accelerate-Stop Distance Required) was greater than ASDA (Accelerate-Stop ...
lemonincider's user avatar
  • 7,565
1 vote
3 answers
4k views

What determines the maximum speeds for a particular aircraft?

Aircraft have three different maximum airspeeds: VMO (maximum operating speed) - the maximum speed that the aircraft is allowed to reach during normal operations. VNE (never exceed speed) - the speed ...
Vikki's user avatar
  • 28.3k