Yak3 Climb

[TonyJoey]

Bozon was mentioning the climb performance of the Yak3, so I did a quick climb in offline. I tried to maintain 100 mph the whole time and was able to reach 10k from the takeoff alt of 0.3k in a little over 2 and a half minutes.

[bozon]

Thanks TJ. 100 mph IAS, 10K climb in just under 2.5 minutes means just under 4000 fpm climb as I said.

I have not watched the film yet. I'll do it when near my AH computer and record my own as well.

[Lusche]

On a general note, please do always use sea level bases when timing climbs to a specific altitude. 

[Lusche]

Ok, reviewed the film and compared it with the default auto climb speed.

In TJ film it took the Yak-3 about 2:35 minutes to go from 750ft to 9.9k (measured from the moment it started to roll). All while staying very close to 100mph indicated
At default climb speed (auto climb), it took about 2:43 minutes for the same altitude difference, at climb speeds between 130 to 160 mph.

And just for the nitpicking record, in neither way the Yak-3 goes from SL to 10K in under 2.5 minutes, and the 109K (WEP) is still faster. But of course this isn't meant as a comment on the validity of the Yak-3 low speed climb capability.

[FLS]

It makes sense that if there is a best climb speed then there must also be worse climb speeds. 

Basically you are changing the parasitic drag to induced drag ratio and increasing your total drag.

[bozon]

It makes sense that if there is a best climb speed then there must also be worse climb speeds. 

Basically you are changing the parasitic drag to induced drag ratio and increasing your total drag.

100 mph is incredibly low speed for a climb, and not a shallow one - almost 4000 fpm climb. Most fighters of that age would fall out of the sky at that speed or barely hold level, so far back on the power curve (i.e. far below best-climb speed). The yak is light but also has small wings. Its not that its wingloading is exceptionally low, nor does it have a very high aspect ratio that can reduce induced drag at high AoA (almost at stall as the stall horn indicates).

I am not saying that this must be wrong, but it is unusual.

[FLS]

The steepest climb is never the best climb rate. Most fighters of the age did not have the performance of the Yak-3 so I don't know why that would be a consideration. The Yak-3 climb rate is a measure of it's specific excess power. The angle of climb is power to weight. TonyJoey has 25% fuel, the Yak-3 climbs at over 4000 fps with full tanks.

[TonyJoey]

Here is another I did with 50 fuel at under 100mph for most of the climb. The time to 10k from liftoff was about the same.

[bozon]

The steepest climb is never the best climb rate.

That is exactly the issue. It is (or just about) the same as the best climb rate for the yak3.

[bozon]

I did some more tests with the yak3.

With flaps out you can really go crazy with this thing. They do add drag so climb rate is lower, but I could now climb at 80-85 mph averaging 2,200 fpm from stand-still to 4000 feet.

Here is an example of how one can throw the yak3 around right after take off, without leaving the perimeter of the field (OK, slipped by a few meters), and most of the time at 100 mph or less. Just trim full rudder left and have at it. I am sure that with a bit of practice there are even crazier moves possible.

Rough landing is my fault for trying to land it sideways. Still counted as "successful".

[alskahawk]

 The idea that you can climb an prop fighter plane at 100 mph or less is ridicules. And to maintain in excess of 3000 ft per min at 100 totally out of whack. 

[FLS]

The idea that you can climb an prop fighter plane at 100 mph or less is ridicules. And to maintain in excess of 3000 ft per min at 100 totally out of whack.  

So what, in your opinion, is the actual slowest speed you can climb a prop fighter?

Keep in mind that your load factor is slightly lower in a climb.

[nrshida]

It's a Harry Potter plane 

[alskahawk]

So what, in your opinion, is the actual slowest speed you can climb a prop fighter?

Keep in mind that your load factor is slightly lower in a climb.

 This plane literally hangs on its prop. It's climb rate should be around 3600 ftm.

[GScholz]

Try that in a P-38. Won't get the same climb rate of course, but the angle is insane. Says something for counter-rotating props.