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Hanni8
12-22-2003, 10:27 PM
I checked the figures for the 109 E-4 and Yak-1:

Yak-1:
Power: 1050 HP
Weight: 2950 kg = Power to weight = 2.8 kg/HP
Wingarea: 17.15 m2 = Wingloading = 172 kg/m2
TT at 1Km: 19.2 sec.
Climb in combat turn: 950 m

109 E-4
Power: 1175 HP
Weight: 2670 kg = Power to weight = 2.3 kg/HP
Wingarea: 16.4 m2 = Wingloading = 162 kg/m2
TT at 1Km: 26.5-29.4 sec.
Climb in combat turn: 500 m !!

The Yak-1 was known for their heavy weight and weak engine, so how is it possible to have a better turnrate and turnradius then the 109 E-4 ? As i was thaught the plane with the lower wingloading has smaller turnradius, and the one with the better power to weight ratio will climb better and have better turnrate (if drag for the two are near).
What is the special constructive detail in the Yak-1, which inspite of lower Power to weight and inferior wingloading makes it the better plane ?

For your answer many thanks in advance

Greets

Hanni8
12-22-2003, 10:27 PM
I checked the figures for the 109 E-4 and Yak-1:

Yak-1:
Power: 1050 HP
Weight: 2950 kg = Power to weight = 2.8 kg/HP
Wingarea: 17.15 m2 = Wingloading = 172 kg/m2
TT at 1Km: 19.2 sec.
Climb in combat turn: 950 m

109 E-4
Power: 1175 HP
Weight: 2670 kg = Power to weight = 2.3 kg/HP
Wingarea: 16.4 m2 = Wingloading = 162 kg/m2
TT at 1Km: 26.5-29.4 sec.
Climb in combat turn: 500 m !!

The Yak-1 was known for their heavy weight and weak engine, so how is it possible to have a better turnrate and turnradius then the 109 E-4 ? As i was thaught the plane with the lower wingloading has smaller turnradius, and the one with the better power to weight ratio will climb better and have better turnrate (if drag for the two are near).
What is the special constructive detail in the Yak-1, which inspite of lower Power to weight and inferior wingloading makes it the better plane ?

For your answer many thanks in advance

Greets

Fennec_P
12-23-2003, 12:01 AM
Thrust also plays a great part in turn radius/rate. Also the design of the wing is important, not just its total area.

You are right, that is a very confusing thing. For another example, the Yak-3 has slightly worse T/W ratio than 109G2, and slightly worse wing loading. Yet, yak-3 out-turn and out-accelerate 109G2 a huge amount, for no apparent reason.

According to numbers, the 109G is "double superior", and should both turn and accelerate better than the Yak-3.

Maybe the bf-109 has more drag?

[This message was edited by Fennec_P on Mon December 22 2003 at 11:19 PM.]

Ugly_Kid
12-23-2003, 12:22 AM
Well the SL topspeeds are E-4 470 km/h and Yak-1 472 km/h. This would hint that Yak is aerodynamically a little bit more streamlined. However, this is also an issue of prop efficiency and also SL power may not be exactly those indicated figures. I think Emil has its best power around 2000 m.

Emil has also a slightly higher aspect ratio of the wing which would mean advantage on induced drag (tight manouvers etc), speed bleed you name it. (Same goes for F vs. Yak-3)

Additionally Emil has high lift devices on leading edge which make a minor improvement in stall characteristics and max. lift factor.

So yes, indeed it looks a bit dubious but the story says that there is real life flight tests data which backs this one up...

karost
12-24-2003, 09:14 AM
if i see aerodynamically between HurricaneMkI and Yak1 I think Yak1 much batter and in history LW pilot most use tactic for high speed attack "HIT AND RUN" so there should have some reason why ?

and Ugly_Kid, I need help :)
I don't have any knowledge about aerodynamic
but I interesting about "Energy Manueverability Diagram", there have any web site show who to make this kind of data ?

I was post to ask Oleg about this
http://forums.ubi.com/eve/forums?a=tpc&s=400102&f=63110913&m=48410083&r=7841 0083#78410083




S!

noshens
12-24-2003, 01:31 PM
bump for boosting E4!

http://www.img.net/cliff-m/vvn/me262.jpg

Kasdeya
12-25-2003, 11:11 PM
Hanni8 wrote:

Yak-1:
Power: 1050 HP
Weight: 2950 kg = Power to weight = 2.8 kg/HP
Wingarea: 17.15 m2 = Wingloading = 172 kg/m2
TT at 1Km: 19.2 sec.
Climb in combat turn: 950 m

109 E-4
Power: 1175 HP
Weight: 2670 kg = Power to weight = 2.3 kg/HP
Wingarea: 16.4 m2 = Wingloading = 162 kg/m2
TT at 1Km: 26.5-29.4 sec.
Climb in combat turn: 500 m !!
__________________________________________________ ____________________________________

Wing area does affect lift. More wing area, more lift. There are some exceptions.

From what I see on this is that some info is not listed. The climb data looks like it should be the other way around, but I am not an aeronautical engineer or someone with enough knowledge for a complete and unarguable answer. I do hope I stirred the pot alittle. http://ubbxforums.ubi.com/infopop/emoticons/icon_smile.gif

Good day.

http://www.revisedevilsdictionary.com/demon.jpg (http://www.IL2airracing.com/)

Hanni8
12-26-2003, 03:13 PM
Thx, for your interesting comments !

Propefficiency: The margins of change for different props is rather small. In many tests i've seen, the difference is nowhere near to explain the massive difference (Yak-1 almost 50 % better in turnclimb then 109).

The superior turn could be explained by a thicker wing which can create some additional lift, because of higher possible AOAs and higher mean lift coeffizients, but this is only available for the prize of additional drag, so the Yak-1 could have a higher initial climbrate, but cetainly should have a lower sustained climbrate which is not the case when being tested. So question remains open.

Hanni8
12-26-2003, 03:31 PM
Ugly_Kid

For the DB 601 Aa the figures are known.
The E-4 was equipped with the DB 601 Aa with 1175 HP (1230 HP for 1 Minute on takeoff).-> See note at the end of the post

Power/Altitude curve:
Power Altitude (m)
1175 0
1000 1000
1040 4000
950 5000 (linear drop with airpressure from here upwards)
800 6000
450 10000

Critical altitude is around 4500 m

Note for 1230 HP override:
The manifold pressure regulator limited pressure below critical altitude to prevent overheating of the engine. At takeoff it was possible to surpass the manifold pressure regulation (1230 hp), this started a timer which after 1 minute reinstated the manifold regulation again.

Source for all this: ISBN 3-7637-6107-1 "Die deutsche Luftfahrt Flugmotoren und Strahltriebwerke"
Authors: Kyrill von Gersdorff-Kurt Grasmann

Greets