The Redbull Race planes all use it and Tom Martin uses it and he won the rocket class at airventure...so...must do something.
Even if it doesnt, it looks cool.
Seems like a good reason to me.
Tom's airplane is built for speed from the wheels up. I once asked him if his inlets were stock (they looked narrow, raked and cool). His reply, "Bob, nothing is stock on this airplane!" Since he beat Mark, Wayne and I by 18 knots in the AVC (and that's a typical margin of victory for him), I believe what he said! His tape is one of those incremental mods I mentioned...not sure how much speed he credits to it...but it actually does look cool (white tape on camo gray in his case).
Gaps seals, I used to have them on my Arrow and they made quite a difference and I sure would like to try them on my -4 so I can get ahead of my buddy's RV-4..( Just a friendly competition )
Do you guys know which model ( size of Mylar seals...they look to be the best ) are required to seal all the gaps on an RV-4??
Sure will be nice to get this thing as fast as it can go without inceasing the HP..
Cheers
Bruno
[email protected]
Just to put an exclamation point on the earlier post that said not to tape any aileron gaps...that's what I was told as well, going into this mod. The word is that some have tried and had real controllabilty issues. I don't think I've heard that its caused a crash, but some very sporting rides, close calls and the need to change a few soiled flight suits. So aileron taping is a no-no, per my mentors and others I've talked to. Caveat: I don't claim to be an expert, but I listened to this warning from the pros!
Bruno, W&W sells a variety of mylar widths. I was trying out the 2" wide mylar, held in place with the recommended double sided tape beneath, and the recommended teflon and plastic tape layers holding it down. I have some 1" mylar as well, but it did not bridge the gaps sufficiently to allow the control surface to move to full throw without getting caught when movement was reversed. I did not use any of the s-channel stuff under the mylar, nor have I tried any of the turbulator tape (I saw a little of it on an SX-300 racer this year). The only place the mylar held was beneath the elevator. Rudder let go first and elevator top let go after. I had a chase plane watching one test hop, and it just shredded and left. It wasn't a cheap experiment, but I learned a bit. I still have the mylar under the lower elevator gap, but it wasn't worth the effort anywhere else...and I haven't seen much of it on other SARL racers (if any).
Biggest lesson: KISS. Tape works well on joints, seams, protrusions, etc. In addition to the areas I mentioned in my first post, I taped my wingtip light lens seams and a few other seams at AVC. Hard to get a head to head comparison of other races, as I ran this one at 15.5K...but the airplane ran great!
Another lesson: I need to work on my intersection fairings to tighten them up to the fuselage and gear legs better. Taping the large gaps I have in some spots there results in shredded tape in places.
A little strategic taping may help by being an additive to other speed mods you undertake. Its easy too. But there is a lot of clean-up on most airframes that is pretty low-hanging fruit, and that will probably make a bigger difference in parasite drag. But a little tape is an easy start...and folks think you're a serious racer when they see you taping up, so perhaps it provides a psycological edge too!
Tom Moore RV-7A Race 21 always uses blue tape on the joints and seams of his airplane. He beat me by 6 seconds over 376 nm in this years Airventure Cup race. First time racer Doug Shoup used tape on his RV-4 Race 96 - especially noticeable on the cowl to fuselage joint. His O-360 powered RV-4 was just 2 kts slower than my untaped RV-6A that I have been modifying for speed for 5-6 years. John Huft RV-8 Race 18 uses it similar to Bob Mills RV-Super 6 Race 43 and he is usually around 25 mph faster than me (he does have a cleaned up IO-360 and he now races in the RV Gold class, bless him). I have heard of control issues when people have altered the aerodynamics of the controls designed in by Van (something more than just covering the fastener access holes). As Bob Mills said, I also have had tape experiments blow off in flight. I made up metal cover plates to cover the rudder and elevator fastener access holes and that seems to work well.
Bob Axsom
Bob's metal hinge gap covers are pretty neat, and surely hold up better than tape...might even block more air than the flexible tape in those big gaps. I tried trimmed mylar there too, and couldn't get it to hold satisfactorily. Tom and John, both very experienced racers, seem to have used a very simple taping scheme (that KISS program again!), but have many underlying mods hidden in the hearts of their beasts!
And this is just one guy's perspective...lot's of YMMV and FWIW wiggle room in there!
For those interested in this stuff, think about coming to a SARL race and joining in, or even just watching. Take a look at some of the planes and talk to the gang...all very friendly and willing to chat. Warning...it can be addictive! (OK, blatant SARL pitch complete!
)
Cheers,
Bob
