Mission for you pony folks!

[Opoch]

Hey guys! I had the pleasure of attending the airshow in Chino, CA today and a learned a little piece of trivia. According to the announcer, and I am inclined to believe him sense the 51D was center stage (they had 10), the paint on the Mustang decreases top speed by about 8 mph.

 

So my question; Does the chrome pony actually go a little bit faster than the painted one? This is vital to the simulation and I just don't know if I can buy the game if it isn't included. :D I need you guys who do have the Mustang to let me know! If I am pleased with the answers there may be some pics in it for you.... perhaps. I haven't checked yet...

[cichlidfan]

I am not going to explore the validity of the statement but I would like to point out that the presence of ten P-51D's does nothing to improve the likelyhood of an air show announcer being correct about anything.;)

[AlphaOneSix]

I know that washing and waxing a dirty Cessna 172 can add up to 5 knots of airspeed...

 

I also know that paint is a non-trivial weight addition...I would guess probably 60-70 pounds for a P-51, but that is only a guess.

Edited May 7, 2012 by AlphaOneSix

[diveplane]

I know that washing and waxing a dirty Cessna 172 can add up to 5 knots of airspeed...

 

I also know that paint is a non-trivial weight addition...I would guess probably 60-70 pounds for a P-51, but that is only a guess.

 

same applies to a car, not so much in terms of speeds but =less fuel burn. lol

[flightace37]

The USAAF did stop having their fighters delivered with full paint jobs after a while. Saves weight and cost.

 

As long as the paint is smooth, it actually improves flow characteristics over raw aluminum (which would contain surface defects). This fact is documented in a few discussions of the P-51's laminar flow wing, and the lack of paint was one of the reasons why it didn't perform completely up to expectations. Sorry I don't have the sources, but you should be able to dig up something through Google.

 

I'm not sure whether the weight savings or better flow characteristics would lead to higher top speeds. I do tend to lean towards the paint helping performance, rather than hurting it. The 8 mph loss would be better attributed to the switch from the birdcage to the bubble canopy.

 

Just for fun though, I'll run a test. Nothing like W.O.T. four feet off the water.

 

EDIT: British Mustang with full paint vs American Mustang in bare metal, standard 68% default fuel. Fully trimmed for level flight, 2600 RPM W.O.T. about 20 feet off the deck, starting with dive from 3k to maximize starting speed. Both aircraft slowed down to and stabilized at 321 knots ground speed according to F2 view after 2 minutes hard run. Variation +/- 2 KIAS with pitching due to manual control. They showed just under 400 mph IAS on the cockpit gauge.

 

Needless to say, I think the paint effect is not modeled. And yes, I did toy with RPM to find the best setting. For the record, 3000 RPM resulted in the speed dropping off to around 312 KIAS.

Edited May 7, 2012 by flightace37

[TimmyD]

If I recall rightly, this has not got too much to do with weight, yeah a couple of hundred litres of lead based paint would add weight to the Mustang but this is more to do with aerodynamics and the orange peel effect in some older paints, which caused irregularities in airflow over the surfaces. For a long time it was a known fact that certain super-car manufacturers painted their cars with the same paint used on fast jets to minimise the chances of the normal paint causing a similar effect on speed and air flow.

[flightace37]

Very good point about orange peel, TimmyD. I wonder which technology was better at the time? That has to be what it comes down to in the end.

 

EDIT:

 

Here's an article discussing laminar flow airfoils, and a bit about the situation with the Mustang:

 

http://www.aviation-history.com/theory/lam-flow.htm

 

Enjoy!

Edited May 7, 2012 by flightace37

[Weta43]

My father worked as an electronics engineer on Hawker Hunters in Germany.

He told me numerous times about how they tried giving one of the aircraft on their base a re-spray & knocked 10 Knots off the top speed.

It isn't if they're painted or not painted, (the plane they re-sprayed was already painted) it's the quality of the finish that makes the difference.

[MegOhm_SD]

Pretty funny your purchase is prdicated on this?..... Really

[Opoch]

Pretty funny your purchase is prdicated on this?..... Really

 

Yep, absolutely! I mean, if this effect isn't moddled then this sim just isn't good enough for me. Sorry ED, you're gonna have to do better! :matrix:

 

I was just kidding…

[159th_Viper]

Both aircraft slowed down to and stabilized at 321 knots ground speed

 

Needless to say, I think the paint effect is not modeled. And yes, I did toy with RPM to find the best setting. For the record, 3000 RPM resulted in the speed dropping off to around 312 KIAS.

 

Miles, not knots.

[flightace37]

Miles, not knots.

 

If the F2 figure that I used to judge ground speed is in mph, then this P-51D is much slower than it should be at sea level. The cockpit gauge is in mph. I very much believe the F2 view speed display is in knots with the options set to use Imperial units. Am I wrong?

 

EDIT: I did make an error in my original post, claiming 312 KIAS for the 3000 RPM speed. That should be knots GS. My apologies for any confusion.

Edited May 7, 2012 by flightace37