Smith's RV-6 wingtip tests

[elippse]

Jim has finally been able to make three sets of data runs at 4000', 6000', 8000' and 10,000' baro altitudes to compare with three sets of data he had taken previously with the standard tips. I took both data sets and obtained a second-order polynomial fit of each tip type vs density altitude. The results are presented below of the curve fit of TAS mph at 1000' intervals from a density altitude of 4000' to a density altitude of 12,000'.

dalt orig new
4000 189.9 197.0
5000 191.4 196.4
6000 192.0 195.6
7000 191.7 194.6
8000 190.4 193.4
9000 188.3 192.0
10,000 185.2 190.3
11,000 181.2 188.5
12,000 ----- 186.5

I didn't list the 12,000' value for the original tips as I felt that was at the extreme edge of the second-order curve and the closest three density altitudes with the original tips were 10,851, 10,885, and 10,998.

For those of a mathematical bent, the coefficients for the original tips are:
-4.669584E-7 * V^2 + 5.762168E-3 * V + 174.2846, and for the new tips:
-1.001908E-7 * V^2 + 2.854875E-4 * V + 197.5071

[Snowflake]

Which tips are these again? Do you have pictures? A 9mph increase at 4000' would be worth investigating for me... A lot of my flying around here is at or below 4000'.

[Bob Kuykendall]

The real question is, what do the short tips do to stall speeds and power-off glide ratios.

[Mike S]

Well, maybe not "worthless" -----but photos sure would be nice

[hydroguy2]

Post number 4 in the following thread, has a pic I believe
http://www.vansairforce.com/communit...ad.php?t=52556

[gasman]

Originally Posted by hydroguy2

Post number 4 in the following thread, has a pic I believe
http://www.vansairforce.com/communit...ad.php?t=52556

I like the looks of my stock flat top wing tips too much..... I don't know how much speed it would take for me to switch.
Let's just say........ ugly

How many G's would it take to tear one off?

[rv7charlie]

Hard to tell for sure from that one pic, but it looks like he should have a placard on the plane thanking Steve Whitman...

Charlie

[elippse]

Originally Posted by Bob Kuykendall

The real question is, what do the short tips do to stall speeds and power-off glide ratios.

These extended tips definitely lower takeoff, landing and stall speeds, while increasing rate-of-climb. Jim took a picture of a bunch of tufts near and at the tips just before a stall and they were straight back.

[Kyle Boatright]

Originally Posted by elippse

These extended tips definitely lower takeoff, landing and stall speeds, while increasing rate-of-climb.

RV-9 anyone?

[Vlad]

Originally Posted by Mike S

Well, maybe not "worthless" -----but photos sure would be nice

I saw it at Oshkosh looks impressive.