Author Topic: Heavier vs Lighter TOP SPEED (Read 439 times)

FLS · « **Reply #15 on:** April 06, 2002, 01:00:41 PM »

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

flecha · « **Reply #16 on:** April 06, 2002, 01:37:03 PM »

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 G´s , 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 that´s in dives where you can pick up speed faster (ask Jug drivers)

C2C
Flecha

FLS · « **Reply #17 on:** April 06, 2002, 05:01:47 PM »

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

eskimo2 · « **Reply #18 on:** April 06, 2002, 08:03:26 PM »

Quote

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

MANDOBLE · « **Reply #19 on:** April 06, 2002, 09:47:23 PM »

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.

pbirmingham · « **Reply #20 on:** April 07, 2002, 12:55:48 AM »

Quote

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.

hitech · « **Reply #21 on:** April 07, 2002, 09:58:24 AM »

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.

MANDOBLE · « **Reply #22 on:** April 07, 2002, 10:27:42 AM »

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.

hitech · « **Reply #23 on:** April 07, 2002, 10:39:15 AM »

Once again mandable: Connects do not effect your planes speed.

And btw did you ever consider the wind?

MANDOBLE · « **Reply #24 on:** April 07, 2002, 02:35:02 PM »

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.

funkedup · « **Reply #25 on:** April 09, 2002, 03:37:00 PM »

LMAO this whole thread.

AKDejaVu · « **Reply #26 on:** April 09, 2002, 05:03:32 PM »

Quote

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

Esme · « **Reply #27 on:** April 13, 2002, 05:06:56 AM »

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"

MANDOBLE · « **Reply #28 on:** April 13, 2002, 06:54:38 AM »

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.

Toad · « **Reply #29 on:** April 13, 2002, 09:24:39 AM »

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.