Originally Posted by claycookiemonster
Thanks. Kinda like asking why there haven't been any new threads about dinosaurs. If you have to ask, you already know the answer.
I just installed a pair in my RV-8 after alot of research (speaking with original RV designer, reading Vans testing document, plus others) and flying a couple of different RV's. They are not necessary but do make a difference in 2 areas for me. The upper leg intersection fairing must be a certain shape to assist as there are several versions and not all are the same. Only the -8's of the RV family experience this due to the placement of the gear legs with the leading edge of the wing.
You can fly without them and will notice at high angle of attack and onset of stall speeds what's called "RV-8 tail shake", tail buffeting stall before the wing root stall. Consider it's use as a poor man's pre-stall warning stick shake. It also skews the true stall speed calcs if you are new to the RV and unsure where the buffeting is coming from.
After installation of the strakes, I no longer have the tail shake stalling effect and the true wing stall onset is +/- 4 knots slower and the break more "aggressive" than before. I had to redo my true stall speed in the POH.
My favorite application of the strakes is the landings, it's reduced the mushy feeling at high angle of attack in the pitch and yaw as I touch down and have more control authority to make much better landings. I was amazed at the difference and really glad I added them. Practically removed the "RV dropin" affect. And I do have the intersection fairings that supposedly eliminated the use of strakes but found in application it's not 100% true.
As a builder I'd recommend, if you may in the future add them, to install during build then remove them so you have the fittings ready to go. Then complete phase 1 without the strakes, get the rigging straight and true, the POH nailed down, etc and move into phase 2. After +/- 50 hours of getting to know your plane add the strakes, you'll feel the difference and hone in your landings to leverage their value and revaluate your slow flight characteristics and stall speeds.