Dive comparison

[Regurge]

fscott's threads got me thinkin about which plane dives fastest in AH, so i did a little comparison.

I set up a wind rise of 127mph, then flew the planes at 5,000ft, manually trimming to keep the vsi at 0. So essentially its a test of max dive speed in an endless 11,176ft/min dive at 5000ft.

Here's what i got:

plane fuel% armament      max tas(mph)*
p51   25    4x.50         570
p51   100   6x.50         585
p47   25    6x.50/267rpg  530
p47   100   8x.50/425rpg  550
p38   100   4x.50/500rpg  545**
f4u1c 100   4x20mm        540
f4u1d 100   6x.50         540
f6f   100   6x.50         520
190a8 100   4x20mm/2x13   555
190a5 100   4x20mm/2x7.7  545
g-10  100   1x20mm/2x13   550
nik2  100   4x20mm/250rpg 520

* all speeds are +/- 5mph tas

** around 520mph the p38 abruptly started to nose over and needed siqnificant up-trim to keep the vsi at zero. Seems like this is mach tuck? If so, thats pretty cool IMO.


So it looks like the pony is the best by far. Also its interesting to see the difference gross weight makes in the dive speeds.

[Voss]

Regurge, you wouldn't happen to know any other sim pilots in Gainesville would you?

If, you go to the University, the guy I am looking for fixes your AC.  

Voss

[Regurge]

Hehe, guess im the only one that cares about this stuff.

Voss, i dont know of any other sim pilots here, but i know a guy who fixes AC at UF. Forgot his name tho. Shoot me an email and i can track him down.

shamblin@ufl.edu

[Jimdandy]

Regurge you've puked up some neat info. That was a neat idea on how to set up the test. Cool stuff.

[LJK Raubvogel]

Regurge...that's good data to have. Has anyone ever done a dive acceleration test? That would be some interesting data to see.

[Widewing]

 

Originally posted by Regurge:
(snipped) So it looks like the pony is the best by far. Also its interesting to see the difference gross weight makes in the dive speeds.

Not long ago, I placed an article on my web site that is focused on dive testing done by Dr. Herb Fisher in the late 1940s. Fisher was testing transonic props for the Propeller Division of Curtiss-Wright. Herb routinely exceeded Mach .80 and reached Mach .83 several times. This means that he pushed his P-47D-30 beyond 600 mph. This aircraft was armed, but did not carry ammunition.

I have several of Herb's hand drawn dive charts, one of which I posted to site. Here it is.

 

In addition, I have also included a color profile of Fisher's P(F)-47D-30-RE with original story, which I'll post here as well. It would make an intersting project for someone into scale modeling.

   

My regards,

Widewing

[Widewing]

 

Originally posted by Regurge:
(snipped) So it looks like the pony is the best by far. Also its interesting to see the difference gross weight makes in the dive speeds.

Not long ago, I placed an article on my web site that is focused on dive testing done by Dr. Herb Fisher in the late 1940s. Fisher was testing transonic props for the Propeller Division of Curtiss-Wright. Herb routinely exceeded Mach .80 and reached Mach .83 several times. This means that he pushed his P-47D-30 beyond 600 mph. This aircraft was armed, but did not carry ammunition.

I have several of Herb's hand drawn dive charts, one of which I posted to site. Here it is.

 

In addition, I have also included a color profile of Fisher's P(F)-47D-30-RE with original story, which I'll post here as well. It would make an intersting project for someone into scale modeling.

   

My regards,

Widewing

[SFRT - Frenchy]

All I know from my AH experience is that most out accelerate the P47 in a dive especially the yak.

Now if I can reach 550 TAS, then I'm ok  as I outmanouever anything that usually is compressing.

I read reports of P47 catching german planes in dives, excuse is supposed to be because it's way heavier. Well, I have no clue as I don't build airplanes but only fly them. My aredynamics knowledge is limited to basic stuff.

[Jimdandy]

 

Originally posted by SFRT - Frenchy:
All I know from my AH experience is that most out accelerate the P47 in a dive especially the yak.

Now if I can reach 550 TAS, then I'm ok  as I outmanouever anything that usually is compressing.

I read reports of P47 catching german planes in dives, excuse is supposed to be because it's way heavier. Well, I have no clue as I don't build airplanes but only fly them. My aredynamics knowledge is limited to basic stuff.

I've read that too. I also read that on the initial dive the 109 could accelerate faster. But in a sustained dive the 47 was faster than the 109.

[funked]

Cool chart Widewing!  Time plots like that are few and far between in my experience!

Frenchy:  Initial dive acceleration at low speeds is primarly dependent on thrust/weight ratio.  Once you are above the maximum level speed of the aircraft (drag exceeds thrust), then the weight becomes the biggest factor.

[This message has been edited by funked (edited 02-02-2001).]