Author Topic: Why the La7 is so Uber(important) (Read 2322 times)

J_A_B · « **Reply #45 on:** October 31, 2002, 04:59:50 PM »

Don't get me wrong F4UDOA, I'm not trying to be an "AH cheerleader". Far from it. I AM playing "devil's advocate" though because we need real proof, rather than conjecture. "Feeling" something is wrong isn't good enough unfortunately. We need something concrete.

The Mosquito has been brought up before. It is also "wierd". Good onfo on the Mossie should be a lot easier to find than info for the LA7. This is a much better direction for this thread!

But if you REALLY want to see something wierd, think about this:

The Hurricane IIc has 22 minutes endurance at MIL power with 121 gallons of fuel. The LA7 has 28 minutes endurance with 122 gallons.

The Hurri 1 has something like 1300 HP MAX, probably less than 1200 on MIL power, yet it has about 22% LESS endurance than the LA7 for the same amount of fuel.

Now THAT is odd.

The more I think about it, it seems as if the AH LA7 is running around on a very lean mixture until it engages WEP. Maybe possible in theory, but it definately seems wierd, wouldn't the dang thing overheat and prematurely detonate?

Now this is total conjecture on my part, but could that have been possible to do without overheating during the very cold Russian winters?

J_A_B

F4UDOA · « **Reply #46 on:** October 31, 2002, 05:05:42 PM »

Heya Cav,

The fuel consumption numbers on that site are a little suspicious. 310 L/Hr = 63 Gallons per hour at mil power at sea level producing roughly 1500HP. That is just this side of impossible.

That would give the La-7 a fuel duration at Mil power of roughly 2 hours, 45 minutes better than the P-51D with all internal tanks full.

If that was true the perpetual motion machine would be just around the corner.

The good news is that it is so close to the Wright Cyclone. That engine I can definitely find numbers for. And I can assure you the f4F didn't have better range than the F6F.

214thCavalier · « **Reply #47 on:** October 31, 2002, 05:20:38 PM »

F4UDOA go and re read my post again, you replied while i was editing and adding more info i was working on.

If you read it you will see i make it 178 US gallons per hour at 1430 HP (I am assuming thats Mil) at sea level.

I kept it as US gallons to make the comparison easier for those who may confuse US gallons while the rest of the world used Imperial gallons.

And why does everyone assume JAB and I are batting for the LA7 ?

We have been trying to keep an open mind and help figure it out without stomping our feet and saying that cannot be !

Now if any smart bellybutton wants to pick holes in that please feel free, I am open to polite corrective actions, well unless your Blond, long legged, big busted and female then abuse me all you want

J_A_B · « **Reply #48 on:** October 31, 2002, 05:33:38 PM »

"And why does everyone assume JAB and I are batting for the LA7 ?

We have been trying to keep an open mind and help figure it out without stomping our feet and saying that cannot be ! "

AMEN!

We're trying to see whether it could be correct or not, and if it IS wrong, then WHY it's wrong--or why it's correct if it happens to be. Look at it from every possible angle.

If you just say "it's wrong" with no support nothing will be changed. If you can say "it's wrong by X amount for THIS reason and here's my proof", then you'll see changes.

J_A_B

214thCavalier · « **Reply #49 on:** October 31, 2002, 05:41:23 PM »

So JAB have you read my post a few up where i worked out 178 US gallons and 147 Imperial at sea level Mil power ?

If so any thoughts on possible errors?

So far to me coming at it from completely different angles with your extrapolating it from AH figures and my working it from grams used per HP per hour it seems AH could well be in the right ball park.

F4UDOA the next time i reply to one of your threads do me a favour and tell me to sod off !

That way i might get to actually play the game instead of wasting an entire night chasing info

J_A_B · « **Reply #50 on:** October 31, 2002, 05:55:18 PM »

Let's for a minute assume the F4U chart posted by F4UDOA is exactly correct. It shows 290 GPH at MIL power (low levels) for the R-2800.

Lets also, for a minute, assume your estimate is also correct--178 GPH.

Now, in AH the F6F runs at 250 GPH and the LA7 runs at about 140 GPH--BOTH are low by about 40 GPH.

Of course, that's a lot of assumptions, but maybe that gives us something to go with.

It's also possible that the F6F might be spot-on and the LA7 might just be running at some crazy lean mixture

J_A_B

214thCavalier · « **Reply #51 on:** October 31, 2002, 06:00:53 PM »

JAB the F6F is on US GALLONS.

Fuel rates for the LA7 are 165 to 178 US gallons.

BUT if you use imperial gallons for the LA7 it works out at 136 to 147 smack in the range AH uses.

Also the F4U chart using the Imperial gallons column is 240 Imp gallons per hour.

Now is that a coincidence or what ? cos they match pretty damn close to AH if you use imperial gallons.

Next thing is to confirm whether the LA7's capacity is in fact in US or Imperial gallons, after all we must compare apples to apples and oranges to oranges

J_A_B · « **Reply #52 on:** October 31, 2002, 06:15:16 PM »

Okay that is a hypothesis--perhaps the LA is sucking down 140 US gallons when it should be using 140 IMP gallons.

Can it be proven right or wrong?

If indeed AH is wrong, then the LA7 would have an endurance of roughly 20 minutes in the MA--this is much more in line with what would be expected from its power output and fuel load.

Unfortunately, I have no good data on the LA7's engine. I can't prove that hypothesis OR disprove it. I hope someone with good data will chime in.

-----------------------------

About the F6F, it flies 30 minutes (60 without the MA multiplier) on 250 gallons of gas, or 250 GPH. I'm not really concerned with the F6F though because I can locate stuff that shows 250 to be correct for the F6F's engine (and apparently HTC can too) and even if it's wrong (which is debatable) it'd only make a tiny difference in AH anyway....it's just not signifigant.

J_A_B

214thCavalier · « **Reply #53 on:** October 31, 2002, 06:46:50 PM »

The earlier figures that were giving ridiculously low consumption figures were from Tilt's page (AH player) and he has a lot of info on the LA7 at,

http://www.btinternet.com/~fulltilt/Lavochkin.html

However i cannot believe the fuel figures he has posted are correct, there has to be an error in that data.

But damn him he does not give the fuel capacity everything else but that !

J_A_B · « **Reply #54 on:** October 31, 2002, 07:00:25 PM »

Tilt's fuel consumption data isn't unbelievable. A lot of websites and general sources list "best" fuel comsumption, right next to "best" power, giving the false impression that the engine would use much less fuel at full power than it actually did.

Those fuel comsumption figures are totally believable if you're talking about cruise settings. It's sort of like how an airplane will often be listed for a "best speed", giving people the false impression that the plane would reach said speed at any altitude (even here in AH we get the occasional person asking why various planes are so much slower than what their books say).

J_A_B

F4UDOA · « **Reply #55 on:** October 31, 2002, 07:11:12 PM »

Cav and JAB,

That could be exactly what the problem is in regard to the La-7 fuel consumption. The 178(US) Gallon would really put it more in line with the expected efficiency levels of other engines.

The strange thing is that if you look at that fuel burn chart again the numbers are all over the place. You would expect certain A/C to be better and some to be worse.

1. The P-40 and P-38 have almost identical endurance. Really?

2. The Hurri 1 has 119 Gallons and the Hurri IIC has 121 gallons but the Hurri I has TWICE the range???

3. The Spit IX has the same range as the Mossie??

4. The F4F/FM-2 have longer range than the F6F and F4U?

5. The NIK2 has a longer range than any American Naval counter part despite having a 2,000HP engine and a 190 gallon tank

6. The F4U-4 has less range than the F4U-1D. Despite having a slightly smaller tank it was rated with a longer combat range.

Just a few Knits to pick.

BTW. Cav. I can't tell you to bugger off. I need you to clear my 6!!

214thCavalier · « **Reply #56 on:** October 31, 2002, 07:25:35 PM »

F4UDOA the figure i worked that 178 US gallons with was 1430 HP now if we take that as approx 75% of the F6F-5's power and add 25% to the fuel consumption rates for the LA7 we get a figure of 237 Gals per hour IF it could produce 2000HP, which of course the LA7 cannot but its damn close to the F6F-5 figure.

F4UDOA · « **Reply #57 on:** October 31, 2002, 08:49:09 PM »

Cav,

Actually I was thinking the opposite of what you are.

I'm thinking that HTC is calculating the range of the La-7 based on Imperial gallons instead of US. I say this because it would be hard to do it the other way without adding weight to the La-7.

And it still doesn't explain the rest of the anomolies.

I think it's about time for Hitech to burst in and call me a whiner or say it's all a figment of my imagination.

wells · « **Reply #58 on:** October 31, 2002, 09:17:12 PM »

Range and Endurance are not the same thing. Range will depend on how fast the plane is flying.

OIO · « **Reply #59 on:** October 31, 2002, 09:50:05 PM »

Uh.. why you throwing all these numbers around?
Just find what was the max flying time for an La7 in WW2 and the max flying time for the F6F or any other fighter and compare them to AH

But I do agree, the La7 and hurri/spits have quite a flight time when you compare them with the long range fighters of their day.

P-47 had almost 2 times the range, the spitfire could barely fly over the french coast while the Jug got near Aachen GERMANY. In AH the Spit and the Jug have almost the same flight time.

And thats what F4UDOA is saying I believe.

For game purposes I can see the furball trash will need their turny cannon planes last quite a while so they can fly to the nearest furball and have their fuel last longer than their ammunition... just like the high alt realism fanatics want their long range zoomMboom rides last a LOT longer in the air so they get a chance to SPEND all their ammo before their fuel runs out.