SOme Specs on Rare Bear

[GregP]

I found out some information on the Reno racer Rare Bear and thought the members might like to see it.

A stock F8F-2 has a wing span of 35.5 ft and a wing area of 244 sq ft.

Rare Bear's specs are as follows:

Span = 30.5 ft
Area = 221.6 sq ft
Effective Aspect Ratio = 4.20
Root Airfoil = NACA 23015, Root Thickness to chord = 15%
Tip Airfoil = NACA 23009, Tip Thickness to chord = 9%
Wing Loading = 38.35 lbs. sq ft
CL @ 540 mph = 0.045
CL @ 490 mph = 0.055
CL @ Landing = .807
CL Max = 1.36
CD = 0.0107 @ 540 mph

Straight line top speed = 540 mph
Closed course speed = 490 mph

Found all this in a technical presentation by Dave Simon, Doug Hillson, and Chase Ashton. It was done right before Rod Lewis bought the aircraft. The only change since then that affects these is the fact that Rod Lewis doesn't use Nitrous Oxide during the race, but the system is still on the aircraft should he change his mind.

I haven't seen this type of information for either Strega or Voodoo in this detail, but we can get some of the data over time.

 

[drgondog]

Greg = CL at 5000 feet above SL? ------------> that will tell you GW

 

[drgondog]

I found out some information on the Reno racer Rare Bear and thought the members might like to see it.

A stock F8F-2 has a wing span of 35.5 ft and a wing area of 244 sq ft.

Rare Bear's specs are as follows:

Span = 30.5 ft
Area = 221.6 sq ft
Effective Aspect Ratio = 4.20
Root Airfoil = NACA 23015, Root Thickness to chord = 15%
Tip Airfoil = NACA 23009, Tip Thickness to chord = 9%

Don't believe they use a 23xxx airfoil.. that was production and the Bearcat had a 23018 at root, 23015 at MAC

Wing Loading = 38.35 lbs. sq ft

Production W/L at combat GW for 244 feet

CL @ 540 mph = 0.045
CL @ 490 mph = 0.055
CL @ Landing = .807
CL Max = 1.36
CD = 0.0107 @ 540 mph

I will run some numbers but I doubt the Bear is running CD total at 0.0107 as the F-16 is much higher than that.

Straight line top speed = 540 mph

I will run some numbers - what is the Thrust HP that is claimed to get 540mph TAS (is that at 5000 above SL?) The Compressibility factor multiplier for total drag is probably 1.2 to 1.3 over baseline drag at 9x10^^6 RN at SL. At that speed for total CDo to be .1070 means that the CDo at speeds in the incompressible range is close to 0.008 ---------> 1/2 of a P-51B/D. Does that sound rational at M=~.70?

Closed course speed = 490 mph

Found all this in a technical presentation by Dave Simon, Doug Hillson, and Chase Ashton. It was done right before Rod Lewis bought the aircraft. The only change since then that affects these is the fact that Rod Lewis doesn't use Nitrous Oxide during the race, but the system is still on the aircraft should he change his mind.

I haven't seen this type of information for either Strega or Voodoo in this detail, but we can get some of the data over time.

Voodo0 starts [when assuming P-51 Wing) with ~.016 for CDo at 9x10^^6 (about 160mph for MAC)way below compressibility drag rise from a stock P-51 airframe.. they could only do so much with canopy and new wing to take it down a little but for Rare Bear they had to peel 1/2 of their parasite drag to get the Cd figures claimed before compensating for compressibility.

Thanks for the data Greg. I will play with simple calcs if you can get estimated HP or Thrust data for the 540mph runs?

 

[GregP]

For anyone interested in it, the report I found can be seen at:

http://www.dept.aoe.vt.edu/~mason/Mason_f/RareBear.pdf

I'm afraid I can't say more than I posted because that's all there is ... but I could easily have missed it. It WAS late at night when I found this.