La-5 vs La-7

[Furious]

I think the perception that the La5 turns better stems from the fact that it is, in most occasions, slower and therefore closer to its corner speed.

[indy007]

I think a tiny little performance increase comes from the lighter nose in the -5. extra cannon + 50 more rounds in the -7. The -7 turns very marginally better if you take a 2 gun version. I could be totally wrong, and somebody please correct me if I am, but with less weight, you should have lower wingloading, giving better overall turn performance... even if it's very, very slight.

ahh, I just tought of my second theory, the placebo effect. When I first started playing, I rolled in on somebody and they started their break. I didn't know the planes well at all and he was about to get away. My wingman (Swarm) yelled across the room "WTF?! YOU CAN TURN WITH HIM!". So I did, and got the kill. Seems silly, but if you tell somebody the plane can do something, they'll do their best to get it done.

[zorstorer]

Originally posted by indy007
I think a tiny little performance increase comes from the lighter nose in the -5. extra cannon + 50 more rounds in the -7. The -7 turns very marginally better if you take a 2 gun version. I could be totally wrong, and somebody please correct me if I am, but with less weight, you should have lower wingloading, giving better overall turn performance... even if it's very, very slight.

The weights have been done to death.....the 2 gun La7 is roughly the same weight as the 3 gun La7.  Can't remember who did the math but the difference is not that great.

[Tilt]

I think the most significant factor in the tabled figures comes from reduced drag.

The weight advantage of the la7 over the early 44 La5FN seems to have been about 100kg  (3320 v 3250). Late La7's actually got heavier but not because of the 3 cannon pack. (In may 45 additional air filtration was added  to the wing ducts with pilot controlled vent flaps. Also heavier ancilary equipment (long range radio etc) was added. This was all post war stuff really.)

The weight reduction was nearly all in the wings by the replacement of  the La5FN's(Gorky) wooden spars for metal ones. How would that influence a change in roll rate?

The La7's prop was an anti flap unit which I assume gave better thrust performance at higher revs. I have no record of the La5fn ever being fitted with this prop yet it was available for the last 6 months of La5FN production.

RL climb rate figures seem to put the (No WEP) La7 and La5fn at roughly the same upto 5000m (5.1>5.2 mins). With an edge to the La7 for WEP'd climbs (4.9 > 5.0 mins).

Why the la5fn should turn better than the la7 I do not know and do not understand I can only think that it is something to do with drag and induced C of G in turn affecting lift. All the drag lost from the La5FN was from the gear wells forward ie infront of the C of G.

But the better turn rate is a matter of record.

So from my perspective in AH

The La7 is obviously faster.

The La7 should either roll the same or faster (lighter wings)

The La7 should climb a little faster (but not much unless you agree that the La5FN had a smaller WEP capacity)

The La5FN should sustain turns slightly quicker.

Stall characturistics should be nearly the same.

The la5FN should scrub e more easily than the La7.

The La5FN should be very prone to prop damage if bounced on the runway when landing nose level.

Both should have a nasty bounce when landing. (But unlike the spit's bounce it did not tip the ac forward)

[Spatula]

Great work guys. Nice summary too Tilt

Thanks.