Aircraft Rate Of Climb Explained 

Battle of the Graphs: 7.0 Jets

Mythbusting: Do Heavy Aircraft Dive Better Than Light Aircraft?

Laminar flow and its effects on performance (P51 case study)

@@AdamTheEnginerd when I think about equations that I know weight doesn't have any effect but I might be wrong

Wanna see all 3 . But 7.0 jets first!

Nice pun?

You've got to be pretty high to laugh at that joke

High as a Dutch Astronaut

@@141Zero XD

​@141Zero you don't have to be such a _downer_

Knowledge is specific excess power.

İn Turkey we have excellent word : The pen is sharper than the sword

@@serdarcam99 and the AP ammo is sharper than the pen

Pen invented that technology

@@rn-zu5ld and the apdsfs the sharpest of all

Hahaha thanks! I've used Matlab for most of my technical videos!

@@AdamTheEnginerd Lol. That's what I used for aero when I was at USAFA.

@@AdamTheEnginerd A fellow MATLAB connoisseur, I see

"Young" I don't think you know what that word means.

Adam514 How old are you?

Big Stud he’s my dad

@@doch.8039 our Dad

Adam514 you’re an University student right? I think so. Also: **WHY NO TEMPEST IN THE VIDEO**

Lmao!

Reminds me of the time when the Gladiator and Ki-10-II actually could do that (in AB). They used to be the first Helicopters in the game ;)

It would take many hours to make haha.

Adam514 The one if I’ve been using is obviously wrong! 😩 If you ever need help doing it, let me know. I’d be happy to help.

Adam514 just include the exact data points and stuff and I’ll put it in a google sheet (if I’m not feeling lazy).

@Nano Underdoge It's wrong, seems like you need to add something like 20 km/h as a rule of thumb, or that's at least my guess.

10-20km/h yeah.

Hahaha I think your physics teacher would be sad to hear that.

Because this topic isn't the job of your physics teacher. Take aero engineering.

I love science and engineering a lot, and I am here just to enjoy some high quality science content that I never got fully in school. :)

Haha that'll never happen. Just people playing to win will never happen, and that's quite straightforward.

Propellers are indeed very important and there is a lot of confusion about them! Short answer: You want the least amount of blades possible, while having enough blades or blade area to effectively use the power of the engine (decent prop efficiency). If we take the Spitfire for example, it started off with 1000 HP and 3 blades. That 3-bladed prop was roughly ideal for that power and the landing gear height. With the Mk XIV, power doubled but the landing gear height didn't change. So they either had to increase the number of blades, or increase the "fatness" of the blades, or a combination of both, to effectively use 2000 HP.

@@AdamTheEnginerd Ah, so that is why they kept 4 blades on the Corsair but had to bend the wings in order to keep that giant prop...Wonder what a gull wing Griffon Spit would have been like...

@@HochgeborenKlown Gull wings on the Corsair was used mainly for a short and stronger landing gear, but the bigger prop is also a nice addition.

@@AdamTheEnginerd The 'short' answer seems a bit longer than expected but I don't think I'd be satisfied with anything less.

I had to use it for this video though!

@@AdamTheEnginerd *That's what they all say, Adam.*

Hahaha I'll be sure to use them more often! Some are still proponents of zoom climbing even after watching the video though.

As far as I have understood the idea with zoom climbing isn't necessarily about climbing efficiently but about keeping your speed while climbing. In jet matches you rarely need to go over 3km in altitude so a decrease in efficiency doesn't matter as much when keeping your speed is more important. Also at top tier jets start being able to zoom climb so high that efficient climbing doesn't matter anymore.

I don't have an issue with people who think it's better in matches to zoom. I have a problem with people saying it's more efficient to zoom climb in jets to gain energy.

We dont disagree on anything then :)

My pleasure mate!

Thanks! Hahaha glad you like them!

For sure, zoom climbing is inefficient!

Thanks for the praise!

Thanks! It's my plan!

Thanks mate!

Thanks, and my pleasure!

My pleasure!

Thanks!

Thanks! It's more accurate to say that lift is just there to counter part of the weight, with the associated induced drag. Indeed lift isn't featured in the RoC equation.

My pleasure!

Thanks Greg! I'm a big fan of your channel if you hadn't noticed ;).

Gotta climb E F F I C I E N T L Y.

@@AdamTheEnginerd even an infinitesimal deviation is unacceptable!!!

My pleasure!

My pleasure!

Nice glad to hear it!

Thanks! That's my plan!

I was doing something similar, but with 4 degrees of AoA. 4 degrees gets pretty close to optimal for most planes.

Thanks mate! I make these kinds of videos from time to time.

@@AdamTheEnginerd always my fav because of the detailed info you bring

Haha congrats!

Thanks mate! Any corrections you'd like to add?

@@AdamTheEnginerd Nope this video is spot on. Especially with the explanation about how rate of climb is based on excess power.

Thanks mate!

My pleasure!

My pleasure!

I had to.

Thanks! Like prop blade angle?

@@AdamTheEnginerd exactly.

Wait till you start talking helicopters. There's a handful.

They have high P/W and UK has good propellers.

The uk has poor control surfaces in SB rudder and elevator are horrendous lol 😂

My pleasure bro!

Thanks mate!

Good project!

@@AdamTheEnginerd I'm having lots of trouble figuring out what to do with the ocean of coefficients, but I'll experiment with it. It made me confused. But hey, confusion is the first step towards understanding. Every time I've gotten confused about aerodynamics, I learned a lot more. It helps get rid of misunderstandings, wrongful assumptions, and to gain good intuition.

Good voice change? You shouldn't get outclimbed by P47s in a K4 indeed haha.

Adam514 yeah it seems like the mic quality went up for that sentence. I really don't know how that was happening with the p47s... I didn't have any secondary loads and I was on 20 min fuel, spaded... I usually climb at around 260km/h ias... it ended with me constantly being on the run, especially having forgotten all aspects of prop defensive flying after playing jets for so long

At 260 IAS in an airspawn map, I wouldn't be surprised if P47M loading min fuel outclimbed you.

Adam514 oh... heh... oops

Thanks for the support!

No there's an optimal angle, and it's not 0 (which is close to level flight). If you arrive at the battle sooner, the enemy also had less time to climb, so as long as your aircraft climbs better, whether you go directly towards climbing enemies or not, you will be higher.

Compare them in what way? You consider nearly 8 min to be short (just asking)?

@@AdamTheEnginerd comparing optimal climb speed, basically that. I consider them short because I think these things are much complex and need more time but you make it very simple and easy to understand. I'm gonna compare it myself I'm curious about different climb speeds.

I'd approximate LF best climb speed at 275 km/h.

My pleasure!

My pleasure man!

It's certainly inefficient! Haha prelude to the ultimate climb video!

Thanks! Could you explain what aspect of them make them amazing?

@@AdamTheEnginerd Everything dude there isnt one thing you do that doesn't make sense and its all presented in a clear manner, I have not encountered anything in any of your videos I haven't understood. Its all around amazing IMO, But Im also not a picky guy and I just nerd out on these explanations

@@nodnerbhu Thanks for the praise! I've dealt with some complicated topics at times too, so congrats on understanding everything! I think I'm good at explaining things 1 on 1 when I know the other person, but that I'd be bad in the teaching role.

I understand what you mean. It's not really my area of expertise though.

Ahhh ok bud just thought it would make an interesting vid Just a question do you play sim at all

@@jonnotuckster8856 Very sparingly.

I’m new to SB as such just trying to get a grip of it tbh

Thanks for the praise! Eventually best RU-vidr all around eh?

Adam514 the skies the limit brother lmao

It changes a bit. You should climb at constant IAS until you reach a certain Mach (around M0.9), and then climb at constant Mach for a bit. Then you level out and accelerate to Mach 1.25-1.5, and resume climbing. That climb profile would suit an aircraft like the F104. Be careful, it's not strictly about altitude. Energy is altitude and speed, so when you zoom climb you trade speed for altitude, so of course you reach higher altitudes earlier, but you'll still be lower on energy compared to an efficient gradual climb.

Bit late of a response, but: You have to adapt your climbing technique to a mix of optimal climb with maximum Specific Exess Power (as shown in the video) and overcoming the drag at Mach numbers from ~0.9 to ~1.2. You might mant to look up the "Kaiser climb technique" or "Rutowski profile". Kaiser and Rutowski did research mid 20th century and describe the minimum time to reach a certain altitude. The optimum profile depends on the specific aircraft that is being flown

You did aircraft climb in AP physics?

Adam514 no not exactly... but can’t we do sum of vertical forces, and solve for the net vertical acceleration, then integrate that to find our vertical velocity? It’s definitely not as easy as what you showed in the video... please correct me if I’m wrong

Aircraft climb is pretty much a bloc on an incline with friction being tugged by a string haha.

I swear you replied to me on another comment. Anyways, physics classes teach a baseline. The other guy was wondering why his physics teacher didn't teach him an application. It's because if you tried teaching every application of physics, you would waste too much time.

I think I manage to make it serious enough while useful for WT players.

That's unfortunately days of work haha.

@@AdamTheEnginerd Welp, we can put hope into your fans!

On most planes it's too slow by 10-20 km/h.

I tested to get the thrust curve in test flight, so it was considered. At its worst, it was only a bit more than 10% less than the 0 speed value.

Some jets though have massive thrust differences. The MiG-21 is one for example, upon release I tested the F-13's thrust at approximately sea level at varying airspeeds, and it basically only had 60% thrust or so available at about 100 knots (~50m/s) while its thrust was optimal around mach 0.95 or so. It was for a bug report because the F-13's engines are known for doing 3900 kgf dry and 5900 wet, but at the time the game only had 3390 dry and 4700 wet, which was a 15% reduction, which coincidentally relates to the old afterburner/dry ratio of 15% before what I presume gaijin realised adding this global afterburner coefficients wouldn't work out too well.

@@ZdrytchX Afterburning jets are different indeed.

Glad to hear that!

270 IAS is more efficient than 350 IAS though.

I see you're a man of culture as well ;). I got the necessary coefficients to calculate drag by following the instructions here: www.reddit.com/r/Warthunder/comments/8nq70p/tutorial_how_to_datamine_or_how_i_learned_to_stop/

I myself don't have such a table haha, and putting one together would takes days of work unfortunately. Thanks for the support!

Haha thanks! Sleep is somewhat important though ;).

When already in the match yeah, but harder target isn't a factor during the initial climb.

Requires testing at multiple speeds for that. And it's also not only the rate of climb that you should consider, but also the acceleration of the aircraft as it climbs higher to keep IAS constant, and that can reduce the apparent optimal climb speed. The higher your climb speed, the more you need to put power into accelerating the aircraft instead of gaining altitude, reducing the apparent climb. What matters though is the energy gained, so the difference in TAS as well as the difference in altitude per second.

@@AdamTheEnginerd It's not "too" hard to test it on the fly. If you want maximum efficiency then you have to put in the work, but for instance I figured out the best option for FW-190D9 would be around 268-274km/h IAS - Elevator position combined with climb rate is a good starting point to figure out the AOA. At first I was using 340km/h IAS as it held a constant 20m/s climb with little to no elevator induced drag and it didn't work as I went too far too low. However starting off at this speed gave me room to test and by slowly pulling up and NOT maxing the climb indicator that only shows 30m/s, then when it started dropping I would gradually level off the plane and try to keep the climb as high as possible. By watching the elevators I knew where it started to "struggle" aerodynamically and kept decreasing pitch until it stopped decreasing climb. I would then get a reading of AOA and keep pitching down more agressively to see if an increase of IAS and thus reduction of AOA would grant a higher climb rate on the gauge. If you can accelerate to a higher climb rate in a short while, then you are on the right path and the AOA induced drag was too high, if not, test it in reverse by comparing it to the eyeballed position, but this time focusing on IAS and climb rate - not AOA and climb rate. When IAS starts dropping without any gain, its time to start levelling and you should be in the ballpark, probably no more than +-7km/h. I'm not a flight fanatic, just went by some physics and logic, trusting the game is atleast decently realistic. I could be completely off, but I can keep up with the BF109s at 5.7, so I take it as a win. :D

What kind of intro? That's my goal, and my pleasure!

My pleasure!

Haha wouldn't it get repetitive? That's the kind of thing that a spreadsheet is for.

Adam514 I guess you could make a spreadsheet... (have you...?) I cant speak for everyone and I'm no expert but spreadsheets are a bit impersonal imo... besides, if you don't let all the data out at a time, you keep demand high and you'll have requests like mine of people asking for specific aircraft 🤓. And you won't have to get in as much detail as this one, you can just link it and say "here's the explanation if you're curious." Just like how you take requests for particular aircraft (which by the way, I was NOT expecting you to keep up as your sub count went up and up. Just like I wasn't expecting quick responses like this). After all, that's what I, and I'm sure many people, like about you. The fact that we can directly ask for stuff and actually get it. It makes us feel more involved and closer to you as a creator (like when you made the yak3vk107 vid when I asked :P, which I don't think I'll ever forget)

The amount of time it takes to get an accurate climb rate chart is massive, hence why there's no spreadsheet. I might do this type of video again for supersonic aircraft, just to show how climbing near Mach 1 is inefficient. Interacting with the audience is my goal! No point to do RU-vid without that imo.

Some exist, but they are a bit inaccurate in my opinion.

I've got 2 tank videos!

More bias edition means worse?

@@AdamTheEnginerd Yes. The more slavic (worse) the more bias

Haha thank you!

Angle of attack would barely change the results since the angle is so small (~1%). Already including the climb angle (theta in the image) is something many people don't do and it's a decent approximation. Angle of attack is even smaller than theta.

@@AdamTheEnginerd When climbing at lower speeds (

@@DoubleA44 Even 10° is very small.

Thanks, and it's my pleasure! Yeah higher prop efficiency definitely means higher climb rate, everything else being equal. If you go from 40% prop efficiency to 80% prop efficiency, you double the thrust or power that can increase your aircraft's energy, so you double climb.

@@AdamTheEnginerd Awsome, so what can I do to see this information in game like you do?

Overlay: forum.warthunder.com/index.php?/topic/483838-warthunder-real-time-information/

The first 2 planes you mention are poor climbers, not much you can do about that. Climbing efficiently always helps though.

Used to

Yeah for sure. Radiator drag is pretty small during climb, extra WEP time more than offsets that.

Lmao there is an optimal descent speed too.

It's more that the climb angle increases at low speed, so some of the thrust helps the lift to counter weight, and this effect is included in the code. The stabilizer effect is also approximated in the code. The formula is simple, but what goes into it isn't ;).

Never realized an aircraft produced drug if an angle of attack exceeds its effective aoa

Lmao thanks. Not really. Only thing that could help is watching my Mig15Bis video.

Wing Commander Abhinandan also had problems with his mig :p

My controls are pretty much default, with MEC added.

My pleasure!

I'll do a MEC video eventually.

It is not more effective in WT. I guess only a test will convince some of you, but then you'll say that the speed was too high/low, that it works on this jet or that jet, etc.

It depends more on wingloading than simply weight, but also on prop efficiency. For D28, around 290 seems optimal.

Yup, skipped the mathematical steps to not lose people.

@@AdamTheEnginerd u were right mi apologies for not developing the equation

That's because by climbing at a constant IAS, you're also increasing TAS as you climb! So some of the energy goes into increasing your kinetic energy in the case of a constant IAS climb because you're constantly accelerating to increase TAS to compensate for a drop in air density as you climb, while at constant TAS everything goes into converting your power into altitude! If you added up kinetic energy and potential energy gained, a constant IAS speed will be better than a constant TAS speed (though your test altitude difference is not that big, there wouldn't be a big difference).

Your teachers taught you this?

Good music.

The local host (black caracteristics box) gives the climb rate already.

@@AdamTheEnginerd how did you get that on screen? I'd love to use that

I have it open on my laptop next to me. If you want it on the same screen, check out "Void Mei" on the WT forums.

Wouldn't change anything for Spitfire and P47. For the Do335, it's quite complicated haha.

Adam514 Why complicated please try it

You're gonna kill both engines quickly if you do it wrong haha.

When they say "climb at 20 degrees", that's not AoA, it's just the angle over the horizon. But yeah climbing at constant IAS is the way to go.

@@AdamTheEnginerd yeah im trying to remember my flight pyhsics. Haven't really flown since my stroke 15 years ago. AoA is the Angle between airfoil centerline and direction of movement. The other ist where the nose is pointing.

Precisely!

What do you mean weight decreases with altitude? If you mean that fuel is burnt and hence the weight of the plane becomes lower, that's true but also applies to every plane (to differing degrees, but not a significant difference in most cases).

@@AdamTheEnginerd No I mean the lower gravity (lower stall speed ect.) and the thinner air (more hp required to stay climb ect.)

In real life gravity is 99.9% of the gravity at sea level at like 15km. Gravity is considered a constant, and it's likely a constant in WT. The thinner air is considered because I gave climb speeds in IAS. 300 IAS provides the same aerodynamic forces at sea level and at 5000m, that's the definition of IAS.

It would be possible, if prop efficiency didn't require going into test flight.

I did! So it doesn't explain the difference. Thanks!

That's a quote? It's like my 15th voiced video! There are a lot of misconceptions surrounding roll rate as well. Thanks for the feedback!

@@AdamTheEnginerd All you need to know for now. www.reddit.com/r/Warthunder/comments/8e4hmb/hitlerbolt_spam/

Lol good times.

@@AdamTheEnginerd I dont have it but i loved watching the slaughter. www.reddit.com/r/Warthunder/comments/8jpwm8/how_it_feels_to_play_the_hitlerbolt/

Always in and out ;). Yak9U climbs very well for the tier though. They might have similar PWR at sea level, but the I225's turbocharger allows it to conserve its engine power while other aircraft's power starts to drop. I225 probably has better aerodynamics too and prop.

@@AdamTheEnginerd makes sense, a shame that the I-225 has so many drawbacks...

Did you now?