Author Topic: Speeds Updated at NetAces (Read 535 times)

hammer · « **on:** January 25, 2006, 09:07:52 AM »

Greetings all,

I have tested most of the planes now and have updated the Plane Speed Graph with the new information.

Some highlights:

25% fuel is the fuel load which matches up to the charts at the HTC web-site. The following planes were within 2 mph of the charts at 1, 10 and 20k using 25% fuel:

A6M2, A6M5, 109E, 109G-2, 109G-6, 109K-4 (tested against G-10 chart), 110G, C205, F4U-1, F4U-1D, F6F5, 190A5, 190D9, La5, La7, N1K2, P38L (J matched up with L), P40E, all P-47s, all P-51s, Tempest, Typhoon, and Yak9U.

Not matching the chart at any fuel load:

F4U-4, FM2, 190A8, Hurri IIC, Ki61, Mossie, all Spits (redone, didn't expect them to match)

Other planes haven't been tested / verified yet.

You can see an example match up with the P-51D chart below. The blue and green lines are chart speeds, the red and yellow lines are tested speeds. Test procedures used are on the web page.

Sable · « **Reply #1 on:** January 25, 2006, 09:24:45 AM »

WTG! Great to see that the charts are getting updated.

Krusty · « **Reply #2 on:** January 25, 2006, 11:56:08 AM »

fuel won't affect top speed, just the time it takes to GET to top speed (inertia/acceleration/weight).

So the only thing you have to worry about gas with is the climb rate or acceleration tests, and from memory you only list speeds, right?

So speeds should be the same at all internal fuel levels.

1K3 · « **Reply #3 on:** January 25, 2006, 03:41:58 PM »

Wtf P-51D is 10 mph faster than it should be at alt.

now thats overmodelled lol!

SuperDud · « **Reply #4 on:** January 25, 2006, 03:45:07 PM »

Cool, thx Hammer. I'll have to check them out!

Sable · « **Reply #5 on:** January 25, 2006, 04:01:12 PM »

Quote

Flight Test Engineering Branch
Wright Field, Dayton, Ohio
15 June 1945
Flight Tests on the North American
P-51D Airplane, AAF No. 44-15342

Quote

A. Clean Configuration (with bomb racks).

1. Maximum speed at critical altitudes

High Blower

War Emergency power (3000 RPM and 67") 26000' 442 MPH
Military power (3000 RPM and 61") 28000' 439 MPH
Normal Rated power (2700 RPM and 46") 29400' 420 MPH

Low Blower

War Emergency power (3000 RPM and 67") 10000' 417 MPH
Military power (3000 RPM and 61") 13200' 413 MPH
Normal Rated power (2700 RPM and 46") 16200' 387 MPH

2. Maximum speed at sea level

War Emergency power (3000 RPM and 67") 375 MPH
Military power (3000 RPM and 61") 364 MPH
Normal Rated power (2700 RPM and 46") 323 MPH

Obviously HT got it totally wrong and it's completely overmodeled.

hammer · « **Reply #6 on:** January 25, 2006, 08:18:34 PM »

Quote

Originally posted by Krusty
fuel won't affect top speed, just the time it takes to GET to top speed (inertia/acceleration/weight).

So the only thing you have to worry about gas with is the climb rate or acceleration tests, and from memory you only list speeds, right?

So speeds should be the same at all internal fuel levels.

Actually, that is what I expected, but not what I found. Granted, I only tried it with one plane (a P-47... can't remember which one). I'll have to go back and look at it again.

Widewing · « **Reply #7 on:** January 25, 2006, 08:22:31 PM »

Quote

Originally posted by hammer
Actually, that is what I expected, but not what I found. Granted, I only tried it with one plane (a P-47... can't remember which one). I'll have to go back and look at it again.

Fuel weight does have a small effect on speed. More weight leads to a slight increase in AoA, thus increasing drag and reducing speed. Typically, the difference will be only 2 to 3 mph in the worst cases.

My regards,

Widewing

Widewing · « **Reply #8 on:** January 25, 2006, 08:27:03 PM »

Quote

Originally posted by Sable
Obviously HT got it totally wrong and it's completely overmodeled.

I've measured the AH2 P-51D at 441 mph in WEP at 25,000 feet. Very close to the Wright Field test data.

My regards,

Widewing

Sable · « **Reply #9 on:** January 25, 2006, 09:53:47 PM »

Quote

Originally posted by Widewing
I've measured the AH2 P-51D at 441 mph in WEP at 25,000 feet. Very close to the Wright Field test data.

My regards,

Widewing

I agree with ya - was a sarcastic comment pointed at previous poster, thus the rolling eyes smiley.