Aces High Bulletin Board
General Forums => Aces High General Discussion => Topic started by: MANDOBLE on April 05, 2002, 06:26:57 PM
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Why here a lighter (less fuel) D9 has a faster TOP level speed than a heavier one? A miracle?
Probably it is even true for all the planeset...
Please, dont tell me that a 420 mph your 2100 HPs are used to keep your plane flying against the gravity, and so the lighter one has more power to fight against drag ...
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inertia?
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favouring the lighter airplane????
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http://www.aero.upm.es/es/servicios_generales/jefatura_estudios/jefest.html
If you have some time and money.
-Sikboy
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Forward motion of the plane gives the lift. Assuming that the two planes you say are in level flight, both planes have the same power but the heavier plane has more drag because it would need more lift to keep it in the air. Isn't it not?
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if your not sure what your talking about, consider for a minute that maybe HiTech knows more about this stuff than you, me and a lot of other people that fly aces high.
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That is true for low speeds, but for 500 mph your lift is much greater than your weight. You may stop your engine (0 Hp), center your controls. and your plane will start climbing for a while.
At these speeds you need to counteract your lift with your elevators to keep flying at level. The heavier plane will need to compensate less than the lighter one, that should mean more drag from the controls of the lighter plane to keep flying at level. At the end that may imply a slower top speed.
All these considering that less fuel doesn't imply a redistribution of the weight in reference with the CG.
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If you wanted some travel, you could come over here (in case you didn't want to stay in Madrid).
http://web.mit.edu/aeroastro/www/academics/undergraduate/degrees.html
Just trying to help
-Sikboy
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<>
For all speeds your weight is equal to your lift in level flight. If the plane is heavier it requires more lift, so more drag at any speed.
ra
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"favouring the lighter airplane????"
doh, understood yer post the other way around.
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Citabria and Ra explain it as I understand it.
It makes sense to me.
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Instead of visiting expensive courses it might be enough to read a book ;)
See How It Flies (http://www.monmouth.com/~jsd/how/)
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Originally posted by ra
[BFor all speeds your weight is equal to your lift in level flight. If the plane is heavier it requires more lift, so more drag at any speed.[/B]
Lets suppose we have a plane with 75% of fuel flying at 450 mph and needing 2 degrees elevator down to keep flying straight and level and the same type of plane with 50% of fuel needing 7 degrees elevator down to keep flying straight and level at that speed. Which one is, normally, suffering more drag?
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i would say they both need to adjust their trim
if you need 7 deg DOWN elevator to fly level you got something wrong, (unless your flying upside down)
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Its not that hard to understand :D
The heavier an object the more lift is required to maintain a given altitude. No wing is 100% efficient, and so the more lift, the more drag, more drag is less speed. Now of course the acceleration of a hevier object is reduced, but no matter how long you wait, a hevier plane will not be a fast as a lighter one in level flight (or climbing of course).
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We had this discussion a month ago.
Mandoble again you post a claim without even posting the speed difference you are complaining about. You try to support your claim with a hypothetical situation that doesn't describe the actual flight conditions you are concerned with.
--)-FLS----
Musketeers
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Hi All
MAndoble A heavier airplane (provided everything else equal) is always to be slower. If your theory were true we all be fighting in Lancasters here.
More wight requires more lift and lift comes at the expense of drag and this is true at any airspeed.
When you push the elevator down in your lighter plane to keep going level you actually disminish angle of attack, reducing lift and drag.
When you want max. acceleration you "unload" your airframe to 0 Gīs , what you actually do is reduce your angle of attack to that of min drag. If we could fold our wings in dives (as falcons do when hunting) that would be acceleration!
In your heavier airframe you got an advatage tho and thatīs in dives where you can pick up speed faster (ask Jug drivers)
C2C
Flecha
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I tested the FW190-D9 at 15k with 25% and 100% fuel loads. In both cases the max level speed was 315 IAS.
Just like with the La-7 max level speed thread, people have posted their misunderstanding of the effect of fuel weight changes on max level speeds. In all other flight conditions except max level speed weight affects performance. Because max level speed is primarily drag limited and the increase in AOA to match the lift to the weight change is negligible there is no appreciable speed difference.
--)-FLS----
Musketeers
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Originally posted by FLS
I tested the FW190-D9 at 15k with 25% and 100% fuel loads. In both cases the max level speed was 315 IAS.
Just like with the La-7 max level speed thread, people have posted their misunderstanding of the effect of fuel weight changes on max level speeds. In all other flight conditions except max level speed weight affects performance. Because max level speed is primarily drag limited and the increase in AOA to match the lift to the weight change is negligible there is no appreciable speed difference.
--)-FLS----
Musketeers
I tried this with a mustang at 5K and saw no difference in speed between 25% an 100%.
In a Lancaster, however, 100% and 13K of bombs max speed was 230 (5k alt.).
At 25% no bombs she cruised at 245 (5k alt.).
Weight does make a difference, but it takes a lot to matter.
eskimo
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After several tests we found a factor much more important than just the fuel load: the connection quality. Faster connection = faster planes. You speed is proportional to your ping.
Put three planes in a file, all the same time, fix the speed to 300 for all of them and the one with better connection will outrun clearly the others, reading all of them 300 mph in their gauges.
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Originally posted by eskimo2
I tried this with a mustang at 5K and saw no difference in speed between 25% an 100%.
In a Lancaster, however, 100% and 13K of bombs max speed was 230 (5k alt.).
At 25% no bombs she cruised at 245 (5k alt.).
Weight does make a difference, but it takes a lot to matter.
eskimo
Also, since induced drag is smaller at high speeds, I'd think a fast plane will suffer fewer changes in total drag as compared to a slower plane like a bomber.
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Mandoble: Connections do not effect the speed of your plane.
What you are seeing is that that given a constant time lag, when
2 side by side planes increase speed there distance lag increases.
Making both planes see each other behind the other. As you go faster the distance you see the other person will increase.
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I know that what I see is that you describe. But the "practical" effect is that you outdistance easily the plane with worse connection.
As an extreme example, yesterday my cnx suddenly degradated a lot. I was flying 190D9 and after killing a marauder 109 I headed towards an enemy base where I found a lower and slower Ki61 trying to climb towards me. As soon as I saw the Ki almost stopped I dived for an easy kill. The Ki pointed nose down and started also a step dive. The Ki outdistanced me by far and as soon as he reversed I noticed the warps. No way what I did, the Ki61 kept outrunning me all the time so I decided to RTP and relog. At this point I was doing 450mph and saw a far La7 chasing me. In less than 30 secs the La7 overpassed me like a rocket (I was still doing 450). And the La7 kept doing very fast passes over me like if I was almost stopped in the air. I saw also a much lower Spit and P51 at my very long six, in less than a minute both overpassed me also while I was about 400mph. La7, Spit and P51 kept attacking and overpassing my D9 for a while until some friendies came to help me.
All the time my NetStatus was showing a very bad cnx on my part.
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Once again mandable: Connects do not effect your planes speed.
And btw did you ever consider the wind?
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HiTech, if the wind was affecting me, it was also affecting the P51, Spit and La7. I was doing 450 mph but for them it was like I was doing 200 mph.
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LMAO this whole thread.
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After several tests we found a factor much more important than just the fuel load: the connection quality. Faster connection = faster planes. You speed is proportional to your ping.
ROTFLMAO! Guess that explains why planes don't move at all in off-line mode?
AKDejaVu
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Mandoble, load up a bomber, lets say my favourite the Ju88, with 100% fuel, 20 50kg bombs, take her up to say 2,000ft then go to an outide view and look at the nose up/down angle she's flying.
Now repeat with 25% fuel and no bombs at all. The difference is weight is about 2,500kg. (Im not entirely sure what the fuel weight carried by the Ju88 is in AH, but everything seems similar to in WB, so I' assuming 25% fuel masses 500kg or thereabouts).
Check the nose up/down angle again. It's more nose-down - and the wing is nearer horizontal than when heavily loaded. So the SAME power, LESS weight, LESS drag (because the heavily laden plane has its wings tilted up slightly, which causes more drag) - so it's not surprising it goes faster.
Its the same with same with all aircraft.
Esme
CO, Kampfgeschwader 2 "Holzhammer"
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Esme, I was refering ONLY to fuel load. And only for those cases where less fuel does not imply any displacement of the CG. We did several tests and, accidentaly, the heavier plane had a poor cnx. We switched sides in another tests, mixing up fuel loads, we then found minimal differences between 75% and 50% top speed due weight, but the plane with better cnx kept outdistancing the others.
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Amazing, simply amazing.
So heavier should be better? Wonder why they didn't stick 200 pound anvils under every pilot seat then? Iron beams for wing spars? Hispanos? Why bother? 88mm cannon.. now THERE'S a gun! Stick a pair in each wing!
Weight is GOOD in aviation, right? That's why designers have spent years trying to make things heavier, not lighter........
Oh, wait......... it's the connex! After more than a decade of this, I've just learned a good connex is better than a bad one!
No end to what you can learn around here.
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Originally posted by MANDOBLE
Faster connection = faster planes. You speed is proportional to your ping.
Cool, I am going to get a T3 connect so that I can still fly my F6F and outpace all those guys on 56k's that are flying 262's.
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ping time has nothing to do with bandwith.
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Toad, I have had a good laughting time with your post. Now try to read something else than the topic of the thread alone.
Now go to TA with another player, pickup 190A5, one with 100%, the other with 75% and be sure both have a good cnx, and then go to max speed and tell me the differences u notice. Then repeat the test with u or the other having cnx degraded.
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I read all of this thread.. it was like a good novel that I just couldn't put down. :)
The weight part was the best, of course.
The connex part was good too. If you are still wondering about it, I'd suggest re-reading what HT told you. Maybe he'll pop in and give it another try but I still don't think you'd be convinced.
Perhaps one of those absolutely free calls via the Internet to Grapevine to talk to HT one-on-one would help you.
Anyway, continue. In this thread, you are quite entertaining.
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I've read this thread a few times trying to figure out just what the hell mandoble is trying to say.
I went on-line and ran this test with a 190A-5. I took it to 5000 feet and leveled. I accelerated to 275 IAS and then dove to the deck where I acheived around 450 IAS then leveled off below 100 feet. I let the speed settle and took a snapshot.
With a full tank of gas:
(http://www.dbstaines.com/images/190SL_Full.gif)
And with a quarter tank of gas:
(http://www.dbstaines.com/images/190SL_Quarter.gif)
There really wasn't much difference, with the slight edge going to the plane with less fuel (the lighter plane).
Then it occured to me... mandoble is probably refering to acceleration. That's when I really started to laugh.
Mandoble... does it take more work to move something that weighs 1000 lbs vs something that weighs 10 lbs? Do you know what horsepower is a measure of?
AKDejaVu