Aces High Bulletin Board

General Forums => Aircraft and Vehicles => Topic started by: niklas on August 21, 2000, 10:20:00 AM

Title: Cd0 of F4u
Post by: niklas on August 21, 2000, 10:20:00 AM

In the older discussion
 http://bbs.hitechcreations.com/smf/Smileys/default/Forum9/HTML/000713.html (http://bbs.hitechcreations.com/smf/Smileys/default/Forum9/HTML/000713.html)
we had the problem that noone knows the Cd0 of a real F4u.
Maybe this can help us: The Naca tested a 1/2.75 scale model with several flaps/elevator settings. The report is
 http://naca.larc.nasa.gov/reports/1942/naca-wr-l-440 (http://naca.larc.nasa.gov/reports/1942/naca-wr-l-440)

The result is basically this: The F4U only can have a Cd0 of ~0.018-0.019 (This is the value for 355mph@sealevel) when the aillerons, rudder and elevator are perfectly centered (0° position), power off (no prop drag?), the horizontal stabilizer is in the lowest possible AoA position to the power line (~1.5°) and the best elevator nose shape.
IMO this is not a configuration where at full power a real F4U will fly straight on...
Look at Cd0 values for more realisic AoA of the horizontal stabilizer, add a bit drag due to elevator, ailleron and rudder deflection, add propeller drag, and you´re quickly in the range of 0.021-0.022. Has a model a better "production" and surface quality than a serial-production F4U-type? I´d say yes.

The only question that remains for me is whether the navy calculated the performance only for the F4U with an irreal low Cd0 or whether this was a usual practise for other fighters too...

niklas

[This message has been edited by niklas (edited 08-21-2000).]

Title: Cd0 of F4u
Post by: Tac on August 21, 2000, 10:43:00 AM

While they are at it, HTC could also look at http://naca.larc.nasa.gov/reports/1920/naca-report-79/ (http://naca.larc.nasa.gov/reports/1920/naca-report-79/)

and maybe this would help make strato-bombing a bit harder  (http://bbs.hitechcreations.com/smf/Smileys/default/biggrin.gif)

This to help with the modeling of german planes:
 http://naca.larc.nasa.gov/reports/1923/naca-report-143/ (http://naca.larc.nasa.gov/reports/1923/naca-report-143/)

This for info on propellers
 http://naca.larc.nasa.gov/reports/1920/naca-report-30/ (http://naca.larc.nasa.gov/reports/1920/naca-report-30/)

am I bored or what?  (http://bbs.hitechcreations.com/smf/Smileys/default/wink.gif)

Title: Cd0 of F4u
Post by: funked on August 21, 2000, 10:52:00 AM

Niklas, the F4U-1D was flight tested at over 360 mph at sea level.  Obviously your analysis is incomplete.

[This message has been edited by funked (edited 08-21-2000).]