Let's make a V1/V2/VR speed table together!

Hey everyone,

as many of you know, my app In-Flight Assistant lets you set V1, V2, and VR speeds so your “co-pilot” calls them out during takeoff. I’ve had quite a few requests to provide a calculator in the app to let you know what those speeds need to be, but the problem is that the formulas for calculating them are quite complex and often are an airline’s secret business knowledge.

So, I had the idea - what if we slowly but surely “crowdsourced” the values for all the airplanes in IF by experimenting ourselves (or consulting actual manuals if we have them 😃), and thus at least find “close enough” speeds? I’d then make the table publicly visible, and add it to the app as a calculator at no additional cost, and we’d all benefit from it!

To make sure we’re all on the same page here, here are what the speeds mean:

V1: the “point of no return” speed - once you reach this speed, you can no longer abort take off but must take off, even if there’s an emergency.
V2: the speed at which you will be able to safely gain altitude even if you lose 1 engine - a typical climbing speed is V2+15.
VR: the speed at which you should gently but firmly pull back on the yoke to lift off the runway.

I’ve made a Google Spreadsheet for this purpose that anyone with access can edit. Here it is.

Here’s a proposal for finding the speeds by experiment - but this may be completely off, so if some of you real pilots have a better idea how to find the correct speeds, I’m all ears.

  1. Let’s all do our experiments on a “normal” 8500 ft. runway: KMIA 08L with no wind.
  2. Set up your weight based on the table cell whose value you want to determine.
  3. Set flaps to 5° (or equivalent - in an Airbus, set it to 1)
  4. Assume a temperature of 15° (normally temperature would influence the V-speeds as well, thanks @CJ12 for this point.

V1 - Start on one end of the runway, accelerate with 95% N1 (this is not 95% throttle), and then figure out the speed at which you no longer can stop before the end of the runway with brakes only.

V2 - Find your stalling speed while climbing at 95% N1 and add 10 knots

VR - Find the speed at which you can pull back on the yoke and gently take off at 95% N1 - you shouldn’t be shooting up like a rocket, nor should it take you forever to get your nose off the ground.

If you would like to take part in this experiment, shoot me a quick PM with your Google account email for edit access to the spreadsheet!

Hope I’m not forgetting something incredibly obvious and important here. 🤣 Let me know if you have any questions!

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Awesome idea. I have a few manuals at my disposal so I’ll look over them and add info as soon as I find the right numbers :)

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Challenge accepted. Sounds tough, yet fun. Interested to see results.

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Sweet, just shoot me your Google account email and I’ll give you edit access and you can start with your favorite aircraft :-)

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@Ben just did some research and found out that V1 is calculated WITHOUT reverse thrust, so only brakes + spoilers!!

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Awesome Idea! I will sure be helping! :)

Better add that in! :)

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One question; how are we going to adjust / determine the V1 speeds for the different length runways? Obviously runway length is the biggest factor, and doing all experiments on an 8,500 ft runway will give us an idea on that length, but those figures will be completely off at KSNA, for example, that has only a 5,700ft runway.

i know it’s a lot of extra work, but should we maybe do it on 3 different length runways and create a new column for each, so users can then use the ‘closest’ runway length to the one they intend to use?

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I was thinking of that as well but let’s do other runway lengths (and flap settings!) after we’re finished with this one - otherwise I’m afraid we may be biting off more than we can chew. 😉

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If anyone else wants edit access to the spreadsheet today, shoot me a PM soon, since I’m going to bed in about 20 minutes. Otherwise you’ll have to wait till tomorrow. 😉


Edit, 40 minutes later
OK I’m off to bed! I’ll try and shoot off a new round of edit access emails in the morning.

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Whoever is editing the sheets as I type this (specifically the 737-800 currently), you SHOULD STOP IMMEDIATELY AND CALCULATE THE VR first! The figures you are putting in are wrong!

V1 cannot exceed VR so there’s no point doing V1 at the lowest weight, because you will have already exceeded VR and be off the ground! I can see you puttting in figures of V1 (35,000kg) as 196knots - that’s great except you’re already in the air by 140knots. REMEMBER; if V1 exceeds VR, then V1 must equal VR

I don’t have an access to the form but I calculated V1 and VR speeds on solo in the last hour (for the 737-800):

80,000 V1-163 VR-174
75,000 V1-164 VR-170
70,000 V1-166 VR-167
65,000 V1-165 VR-165
60,000 V1-162 VR-162
55,000 V1-159 VR-159
50,000 V1-155 VR-155
45,000 V1-150 VR-150
40,000 V1-141 VR-141
35,000 N/A Empty weight 36,600

As you can see, from 65,000kg and lower, the V1 and VR speeds are equal. At 65,000kg, the V1 speeds have increased and have matched the VR speeds which have decreased. At that point, they become equal for all lower values

@epaga maybe remind people that you give access to of this, otherwise these sheets will be inaccurate and therefore useless

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I did think about this, and how it the V1 speed would be so high. However, we would want this to be as close as possible. Maybe, for some odd reason, someone would still be on the ground at 196 knots, and decides to abort takeoff. Yes, the VR callout would take place first, but the V1 callout would still be there. It is worth a test. Just incase someone would like to know, that data would still be there, just incase that scenario arises. Also, the data you collected is incorrect. As the weight goes up, the V1 will go down, and vise versa. Also, this data is not in any way finalized or official, so do not take this as fact or anything. Still in progress. If you would like more info, PM me.

Edit: After reading your post several more times, I finally understand you. You could of phrased it better, the data I have is not wrong, but it is useless. You are correct, there is not point in calculating V1 in an aircraft of that weight. If V1 is higher than V1, they are equal.

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The consensus is if you hit Vr, you rotate no matter what unless you lost both of your engines or something similarly catastrophic happened. High-speed aborts are risky and you might be better off in the air dealing with a problem than trying to stop an aircraft with millions, if not billions of joules of kinetic energy.

Boeing 787-8 completed:

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AWESOME. Just woke up to this. Arguably, the 787-8 is the most popular aircraft, and we already have it covered! How great is that! 🙂

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I think @Yuan_Tugo could help. I’m pretty sure he’s an A320 pilot.

Sir is there any chance of this app coming in for Android? I want it soo much 😥

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He’s said this many, many times. There are no plans for an Android version in the near future.

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Ohkay!! 😞 but it would do him a great profit in play store as well as help android players

Yes, while it would do exactly that, it’s very hard to port a whole app from one native operating system to another. If @epaga could easily do it, he would.

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