Recommended Climb Speeds

[=IRFC=Gascan]

I just went through and marked down the climb speeds recommended by the in-game tooltips just after takeoff. Blue numbers are converted from the original unit. What does everyone else thing about these numbers? I notice some of the exact same airframes with different engines have different recommended climb speeds, but not all. Is this due to the different engine? For example, the D.VII said 127 kph, but the D.VIIF said 117 kph. Both variants of the SPAD 7 were recommended 110kph. The Bristol with Falcon 2 and Falcon 3 engines are at 71 and 72 mph respectively. The Halberstadt with the 180hp engine needed 103 kph, while the 200hp engine needed 106. This means in some cases, the more powerful engine is recommended a slower climb speed, while in others it is recommended at faster climb speed. Changing the loadout doesn't seem to affect it either, as I tried a SPAD 7 180 with and without the Lewis over-wing gun, and the same climb speed was recommended.

I'm not an aeronautical engineer nor am I a trained pilot, so I have a number of questions. Are these climb speeds reasonable, or do pilots have their own recommendations? Does this recommended climb speed work best at all altitudes, or does the best climb speed change with altitude? Why the difference between different engines but same airframe? If I'm leading a formation and have to back off throttle by a couple percent (perhaps 98%) to let a wingman catch up, should I nose down a bit to maintain this same speed, or maintain the same attitude? Other than timing it, is there a better method to measure your rate of climb (perhaps Tacview)?

[Avimimus]

It should change quite a bit with altitude.

 

By the way, has anyone thought of building a tool (like those used for Tool-assisted speedruns) to help reverse engineer flight models? Program a set of inputs and see how it does? The tool would allow repeatability and continued tweaking (making systematic tests possible).

 

I'm particularly interested in the maximum turn rate (and minimum turn radius) that aircraft can achieve without losing altitude. I think that would be a very interesting datapoint to have. Also, linear acceleration would be interesting.

[Holtzauge]

On 5/13/2023 at 3:41 AM, =IRFC=Gascan said:

I just went through and marked down the climb speeds recommended by the in-game tooltips just after takeoff. Blue numbers are converted from the original unit. What does everyone else thing about these numbers? I notice some of the exact same airframes with different engines have different recommended climb speeds, but not all. Is this due to the different engine? For example, the D.VII said 127 kph, but the D.VIIF said 117 kph. Both variants of the SPAD 7 were recommended 110kph. The Bristol with Falcon 2 and Falcon 3 engines are at 71 and 72 mph respectively. The Halberstadt with the 180hp engine needed 103 kph, while the 200hp engine needed 106. This means in some cases, the more powerful engine is recommended a slower climb speed, while in others it is recommended at faster climb speed. Changing the loadout doesn't seem to affect it either, as I tried a SPAD 7 180 with and without the Lewis over-wing gun, and the same climb speed was recommended.

I'm not an aeronautical engineer nor am I a trained pilot, so I have a number of questions. Are these climb speeds reasonable, or do pilots have their own recommendations? Does this recommended climb speed work best at all altitudes, or does the best climb speed change with altitude? Why the difference between different engines but same airframe? If I'm leading a formation and have to back off throttle by a couple percent (perhaps 98%) to let a wingman catch up, should I nose down a bit to maintain this same speed, or maintain the same attitude? Other than timing it, is there a better method to measure your rate of climb (perhaps Tacview)?

 

If these are the speeds for best climb performance in-game there are a few things that stick out (may be more, this is just based on a cursory look):

 

The speeds for the SPAD S.XIII and S.E.5a look about right and aligned with my simulation results but that the Camel’s should have its best climb speed as high as 130.3 km/h IAS (same as S.E.5a) IRL I doubt. For me the Camel and Fokker Dr.I should have the best climb rate at around 95-100 Km/h IAS.

 

That the Fokker D.VII climbs better at 127 km/h than at 117 Km/h is also strange: I get better results at 117 also for the Mercedes powered Fokker D.VII.

 

In addition, while I have not modeled the 150 or 180 hp SPAD’s yet, I predict they will climb better at 130 km/h IAS and not 110 Km/h IAS just as the SPAD S.XIII.

 

Finally, calculating best climb rate and speed is tricky: Usually, literature will calculate the specific excess power (SEP) climb rate which is only valid at small climb angles. But even WW1 aircraft climb at relatively steep angles and to get a really accurate result in my simulations, I let the computer try out different climb angles and speeds to determine what is best. SEP derived climb rates are usually not far off, but a difference of 0.5 m/s (100 fpm) is not unusual.

[czech693]

I think the Camel is underpowered.  It takes a lot longer to get off the ground compared to the others.

[=IRFC=Gascan]

I don't know if these speeds will actually achieve best climb or not, they are just what the game recommends via tooltips. I know that when I fly the Camel, SE5, and Dolphin, all of them seem to get best climb at around 75-80 mph, so that's what I usually recommend to other players flying with me. I haven't done any data runs to try and time a climb at any speed, though, so my experience isn't exactly objective. I am not as familiar with the SPAD or the German planes, so I don't know how well the tooltip matches player experience on those.

[1PL-Husar-1Esk]

I read that rule of thumb is just 1.2 the stall speed as  the  best climb rate or was it the best glide speed, i need to check that...

Edited May 21, 2023 by 1PL-Husar-1Esk

[Holtzauge]

9 hours ago, =IRFC=Gascan said:

I don't know if these speeds will actually achieve best climb or not, they are just what the game recommends via tooltips. I know that when I fly the Camel, SE5, and Dolphin, all of them seem to get best climb at around 75-80 mph, so that's what I usually recommend to other players flying with me. I haven't done any data runs to try and time a climb at any speed, though, so my experience isn't exactly objective. I am not as familiar with the SPAD or the German planes, so I don't know how well the tooltip matches player experience on those.

 

13 minutes ago, 1PL-Husar-1Esk said:

I read that rule of thumb is just 1.2 the stall speed as  the  best climb rate or was it the best glide speed, i need to check that...

 

Well 75-80 mph sounds very plausible for the S.E.5a and Dolphin but high for the Camel. In addition, it would be good then if those who fly MP regularly with the other planes weigh in and give us those numbers as well since I'm sure they would have figured that out through trial and error by now. I mean if your virtual "life" is on the line, I would expect you to know your numbers! 

 

 

Edited May 21, 2023 by Holtzauge