[Bob Axsom]

I have had an aversion to taping joints and gaps for speed because I think of it as detracting from the beauty of the airplane and in cases where I have tried it there is a tendency for it to blow off at speed. However, I am getting to a short list of things I can do to further increase the speed.

I bought some gaffer's tape as suggested here some time ago and the minimum order was something like $100 so I have an adequate supply to experiment with. At Courtland, Alabama last Saturday I had a roll with me and some time to kill so I did a little work. I taped the joint between my nose wheel fairing and the sub fairing and I made a tape fillet on the out board side of the outboard aileron mounts. On one of the fillets I installed a span wise cover strip to reinforce the fillet attachment to the inboard side of the mount because the fillet wrap around seemed deficient.

My speed for the 125 mile race was 215.83 mph and there were hard turns in both directions. After the race I inspected the tape. The tape on the nose wheel fairing looked exactly like it did before the race. The overlay cross strip on the one aileron fillet was rolled back into a tight little knot but was still attached. The other fillet tape looked similar to the before race condition except the the inboard wraparound flap was not actually sticking to inboard surface of the aileron mount.

Yesterday when I went out to the hangar to restore some things like reinstalling the nav antenna elements I decided to take this taping thing a little further. I thought that closing the small gaps between the landing dear fairing elements might improve the speed a little so I did it. I haven't tested it so I have no semi-hard performance data (that's as good as it gets from me) but it looks like it should have less drag.

In the process I developed the beginning of some "feel" for the characteristics of this material and some primitive application techniques. I like the way it can be worked to conform to compound shapes during the application - it's not just a stiff tape that kinks when it is forced change direction slightly. From my aileron experiment I know that it will catch the wind and roll off if it is applied in an edge on cross wind direction. I have seen other tapes in use by fellows like Tom Moore that is narrower and more plastic looking so there are probably even better tapes in use.

I will use a 182 kt reference speed to judge if the taped fairing joints provide any improvement in speed. In the mean time I would be interested to hear from anyone on their actual race taping experience.

Bob Axsom

 

[hevansrv7a]

Tape material

Bob, I don't claim to have worked with it as much as you have, but I discovered "hockey tape" recently. It is translucent, tough, very sticky and yet easily removed. In my small experiments, it stayed on at 200 mph with no problem. It is also quite inexpensive. If you can't find it where you are, PM or email me. Another kind of tape that worked well is the new Mylar or similar, shiny HVAC tape. That has the additional advantage of being extremely thin so as not to create much of an edge to the airstream. This is not duct tape in the "Duck Tape" sense.

 

[rvmills]

Bob,

3M 471 tape is what many Reno racers use. John Huft introduced me to it. We use the red, and I saw it here on Amazon in blue.

I've been buying it from Gillis & Lane in Redwood City, CA (where I grew up). Their number is: (650) 367 9900, and they have an Austin Store at (512) 442 1305, for all the Taylor boys and girls...and those in parts east, like you Bob.

It comes in clear, and I've used a bit of it too. Clear seemed to leave a bit more residue...not sure why. Both leave some.

Conforms well to curves, holds up well in most locations (I can't get anything to stay on my upper intersection fairings...they need work).

Something for your bag of tricks. If you find something that works well, would love to try it too!

Cheers,
Bob

 

[Bob Axsom]

Valued input

I have added the 3M 471 to my list of things to try. I am going to go with the gaffer's tape in the last race of the year at Taylor but this is exactly the kind of information I was looking for.

I have a more substantial fairing fix for the aileron mounting structure but that will be an "during the winter" mod.

Bob Axsom

 

[David Paule]

Many years ago when I was working in the flight test industry out at Edwards AFB, the technicians would use "armament tape," sort of a cross between gaffer's tape and duct tape, to tape instrumentation wiring externally on aircraft surfaces.

The rule was that the tape itself was fine for subsonic flight, but they needed to epoxy the edges if that flight was intended to go supersonic.

The epoxy was somewhat thick and left significant blobs on the edges.

 

[Bob Axsom]

Was it a green tape?

Many years ago when I was working in the flight test industry out at Edwards AFB, the technicians would use "armament tape," sort of a cross between gaffer's tape and duct tape, to tape instrumentation wiring externally on aircraft surfaces.

The rule was that the tape itself was fine for subsonic flight, but they needed to epoxy the edges if that flight was intended to go supersonic.

The epoxy was somewhat thick and left significant blobs on the edges.

I recall a green tape (not pretty but not olive drab either) it my distant past could that have been it. I am about .6 to .7 Mach from going supersonic (but I am working on it) so I can get away without the epoxy. Thanks for the input.

Bob Axsom

 

[David Paule]

As I remember the tape was a dark green. Probably the same stuff.

A little bit of an extension to that - an SR-71 is limited to 500 kts at sea level, if I remember correctly. I've got a fast sailboat so I was curious what would be the same dynamic pressure in water. Turns out to be roughly 17 kts. These boats can do about 20 kts.

One day, a similar sailboat ripped one of the floats on some rocks and we duct-taped it together so he could sail it back to his dock and trailer. I advised him to not exceed 17 kts and he'd be okay.

He sailed the rest of the afternoon without issue.

 

[az_gila]

471 tape is also...

I have added the 3M 471 to my list of things to try. I am going to go with the gaffer's tape in the last race of the year at Taylor but this is exactly the kind of information I was looking for.

I have a more substantial fairing fix for the aileron mounting structure but that will be an "during the winter" mod.

Bob Axsom

...the good "glider tape".

If you have a 3M tape distributer near you it is usually stocked and comes in many widths (and colors).

Unlike the Ace hardware "plastic tape" the 471 leaves very little residue behind, even if left on for a long time.

Another option might be 3M #483 tape with more stretch -

http://www.wingsandwheels.com/page28.htm

 

[lostpilot28]

...the good "glider tape".

If you have a 3M tape distributer near you it is usually stocked and comes in many widths (and colors).

Unlike the Ace hardware "plastic tape" the 471 leaves very little residue behind, even if left on for a long time.

Another option might be 3M #483 tape with more stretch -

http://www.wingsandwheels.com/page28.htm

This thread is good timing...I've been needing to buy some 2" wide white vinyl tape to protect my nose-gear fairing for when I remove my cowl. Funny thing is, the 3M #471 tape you guys are talking about is over $33 for a single roll!

I think I'll try the "regular" 3M tape that's $4 a roll. I can remove the glue with some Avgas someday if needed. I'd rather spend my additional $29 on something else. If it comes off early that's OK. I'll have 108 feet to go through before I need another $4 roll.

 

[az_gila]

E-Bay...

This thread is good timing...I've been needing to buy some 2" wide white vinyl tape to protect my nose-gear fairing for when I remove my cowl. Funny thing is, the 3M #471 tape you guys are talking about is over $33 for a single roll!

I think I'll try the "regular" 3M tape that's $4 a roll. I can remove the glue with some Avgas someday if needed. I'd rather spend my additional $29 on something else. If it comes off early that's OK. I'll have 108 feet to go through before I need another $4 roll.

It can also come in pretty colors to match your paint job...

http://cgi.ebay.com/3M-021200-04311...219?pt=LH_DefaultDomain_0&hash=item58881b37f3

 

[Bob Axsom]

File Folders work very well for "A" cowl removal

This thread is good timing...I've been needing to buy some 2" wide white vinyl tape to protect my nose-gear fairing for when I remove my cowl. Funny thing is, the 3M #471 tape you guys are talking about is over $33 for a single roll!

I think I'll try the "regular" 3M tape that's $4 a roll. I can remove the glue with some Avgas someday if needed. I'd rather spend my additional $29 on something else. If it comes off early that's OK. I'll have 108 feet to go through before I need another $4 roll.

I made a wrap around sleeve for the nose gear strut (two pieces required for length) taped together on the back side of the strut for and a two pieces in the form of a notched plate (taped together) for protection from the spinner.

Six years of experience and the only requirement is occasionally they wear out and need to be replaced.

Bob Axsom

 

[lostpilot28]

It can also come in pretty colors to match your paint job...

http://cgi.ebay.com/3M-021200-04311...219?pt=LH_DefaultDomain_0&hash=item58881b37f3

Thanks, Gil! I used to check eBay all the time, but haven't lately. That $15 is much better than $33!

I made a wrap around sleeve for the nose gear strut (two pieces required for length) taped together on the back side of the strut for and a two pieces in the form of a notched plate (taped together) for protection from the spinner.

Six years of experience and the only requirement is occasionally they wear out and need to be replaced.

Bob Axsom

I wish I had that insight before I put a couple little nicks in my nose-gear leg fairing. I'm hoping the tape will match the paint so I don't have to re-spray it.

 

[rvmills]

Just checked with Gillis and Lane, and they no longer stock 471 or 483. They can order it, but you have to buy a case!

RS Hughes has 471 in stock and can get 483...no min order. But it is expensive. I'll look at the link Gil posted...ebay may be the way to go.

The rep at RS Hughes looked at the MSDS while we were talking, and 483 has better elasticity, but lower adhesion...though for racing it may very well be enough. I'm getting a sample of 483 from them to test it a bit...will bring both 471 and 483 to Taylor Bob (if I have the 483 by then). It'll be red, but it will match Bluebird's trim!

Cheers,
Bob

 

[Bob Axsom]

Ordered a roll of 3M 471 Blue from Amazon $25

Ordered a roll of 3M 471 Blue from Amazon $25. All of the rest of the colors were more - as much as $12 more.

Bob Axsom

 

[rvmills]

Well shoot Bob, I'm gonna paint my airplane 3M471 Blue...in a thousand rolls of tape I'll have paid for my paint job!

I noticed the price differential while browsing for tape last night too...go figure...must be a supply/demand thing. Red is pricey...dog-gone-it! (All those red Reno hot rods running up the price! )

I'll still bring the 483 if I have it Bob...so we can experiment with it. Glad you found some blue!

One thing I did find when applying...if its cold out, do it in a warm hangar if possible...it gets less elastic as it gets cold (both the air and the skin of the plane). Just another $.02.

Condition inspection this weekend, so I get to do all the tape over again!

C-YA in Taylor!!

Cheers,
Bob

 

[tcone1]

Clear Box tape

Bob,

What was the verdict on the clear stuff I gave you a sample of?

Not that I'd let you be my guinea pig

 

[rvmills]

Bob,

What was the verdict on the clear stuff I gave you a sample of?

Not that I'd let you be my guinea pig

Slick,

I'm going to test it at Taylor as well. Will use it to tape the cowling seams (so the flames still show!! ). Will let you know how it works.

Didn't have any specific names/numbers for this tape or testing results, so didn't post on it yet. Do you have a mfgr name and tape name/number?

For Bob A and others, my West Coast Raven formation bro Slick Cone gave me some clear 1" tape that I'm also going to try. Will show it to you there Bob. Supposed to leave no residue.

I used clear 471 tape on my cowling seams for the Pagosa 100, and Slick saw how much residue was left after I pulled if off, so he gave me this stuff. We'll see how it works and how clean it comes off. The residue of the clear 471 surprised me, but I think the heat of the engine (or hot air trying to get out of the seams) may have caused more residue (certainly more than I've seen elsewhere). If the latter is true, taping those seams should be a good thing to do, as it should make cooling more effective, by decreasing leaks (I think...that gets into the witchcraft world of cooling drag, so I won't claim to know absolutes there! ).

Thanks Slick!

Cheers,
Nasty

 

[breister]

Duct tape now comes in white (and at least one or two other colors) at Home Depot, matching many planes. I use it across the gap between my wing and the wing stub (removable wing, about 3/8th inch gap) and have flown 250MPH IAS in a descent (not an RV, don't ding me for exceeding Vne!) without apparent issue.

Don't know about residue, but since the gap is always there and will always be covered, I don't suppose it matters as much. Only thing I don't know yet is how well it holds up to rain.

 

[Bob Axsom]

Test results

I revised my base line from 182 kts down to 181.4 kts. That is the speed I got in the exact test configuration without tape (and without the NACA vent covers installed). I made two flights today at 6,000 ft density altitude per the USAR handicap procedure. Three legs were flown, 360, 120 and 240. Wide open throttle, leaned ~100 deg. rich of peak EGT cylinder #4, 2720 RPM, TruTrac Pictorial Pilot tracks, Altrac altitude hold. The average of 5, 20 second interval GPS Ground Speed recordings from each track were input to the NTPS spreadsheet to determine the KTAS.

The first test was with all of the landing gear gaps/seams taped with Gaffer's tape. Speed 183.8.

Inspection revealed that all of the tape was still in preflight condition except the rear of the upper right main strut cuff. I decided to add a piece of tape around the back side of this location to see if it would stay attached or it would peel off.

I landed, refueled and taped the cowl seams and repeated the test. Speed 184.0

Inspection after the flight revealed that the upper right MLG strut cuff tape fix worked very well. On the down side the leading edge of the left side lower cowl tape was peeled back about 1/2".

Bob Axsom

P. S. The peeled back tape on the left side of the lower cowl no doubt held down the speed slightly so the gain is probably more than 0.2 KTAS. I had little time to work on this so the tape was applied over the surface "as is". I suspect with proper cleaning the flap would not have occurred. It is clear that the landing gear cuff gaps and seams cause significant drag. My wife and I are going to Branson tomorrow and return Thursday. Then Friday I fly to Taylor Texas to compete in the Rocket 100 cross country air race. I plan to leave the landing gear tape as is but do some cleanup and retape the cowl seals Thursday after we get home. I will take the tape to Taylor with me and if something came loose in route I will have time to make onsite repairs.

RWA

 

[Bob Axsom]

Tape Photos

Here are a few of the taping photos:

Bob Axsom

 

[rvn817j]

A Question from the 'Un-informed'

I've been following this thread with interest. A guy in a hanger across the taxiway from me uses glider gap seal tape on his aileron gaps. Is there some reason glider gap seal tape doesn't work for all gaps? (I've placed a link to one kind of the tape below and it does not appear to be real expensive. That site also carries the 3M 483 tape.) Thanks.

http://www.cumulus-soaring.com/bowlus.htm

 

[Bob Axsom]

Thanks for the link

I've been following this thread with interest. A guy in a hanger across the taxiway from me uses glider gap seal tape on his aileron gaps. Is there some reason glider gap seal tape doesn't work for all gaps? (I've placed a link to one kind of the tape below and it does not appear to be real expensive. That site also carries the 3M 483 tape.) Thanks.

http://www.cumulus-soaring.com/bowlus.htm

I read the informationand it sounds like the product would work very well where I am using tape to seal gaps and seams on the landing gear and cowl. I would not use it or any form of gap seal on the ailerons on my RV-6A because the dynamic function would be impaired or defeated. The link says it should not be used on control surfaces for another reason but I will not use it there period so their reason doesn't matter to me. Others in this forum have reported trying it and found that the handling was greatly impacted. I really like the way my airplane handles and would not we willing to sacrifice that for anything.

Thanks again for the information on this product - it looks promising.

Bob Axsom

P.S. The taping I did appears to yield 2.6 KTAS at 6,000 d alt.

RWA

 

[Snowflake]

Bob, I can't help but notice in the picture of your cowl with all the tape on it, that your NACA air scoop is still open. Have you tried taping that up too?

 

[Bob Axsom]

I have and it does work but I have a mod plate now

Bob, I can't help but notice in the picture of your cowl with all the tape on it, that your NACA air scoop is still open. Have you tried taping that up too?

I put a cover plate in the NACA vent now for racing. They mount with one screw and I keep them in a folder behind the passenger seat until race time. There is a thread covering that mod in this forum. My test at 6,000 ft dalt showed an increase of .9 kts with the cover in place.

Bob Axsom

 

[Bob Axsom]

3M 471 trial

My wife and I got back from Branson around noon and I went to the hangar after lunch to prep the plane for the trip to Taylor tomorrow. I removed the gaffer's tape around the aft end of the cowl, washed the plane and installed 471 tape at the aft end of the cowl. The color is what might be called electric blue and it is not a real good combination with the dark blue paint but it is only for the race. I will fly to Taylor and learn from that how it holds up. You may recall the gaffer's tape peeled back at one location (left side lower cowl) when I tested it. The Gaffer's tape is much more pleasant to work with on applications that are not flat and non-straight lines. The 471 tape kinks with sideward displacements and I had to apply it in two strips to avoid this. The 471 appears to be lower profile and may not be caught by the wind as easily as the Gaffer's tape but given a clean surface the gaffer's tape may have stayed attached everywhere. I am taking a roll of each with me to Texas and will do whatever cleanup is required when I get to Taylor.

Bob Axsom

 

[rvmills]

Bob,

I have a roll of red 471 and red 483 tape that you are also welcome to test, compare or try out (might match the stripes on Blurbird ). I arrived in Taylor today and will be taping up tomorrow afternoon. See you this weekend!

Cheers,
Bob

 

[Bob Axsom]

I'll see you there

If the tape holds up for the trip I will race with it as is. It does make a difference but it ain't purty.

Bob Axsom

 

[Bob Axsom]

It did not hold up

At one point on the right side the trailing edge of the tap (on the fuselage aft of the cowl) shattered and was almost completely gone. On the left side of the lower cowl the tape was lifted on the leading edge just like the gffer's tape but it wasn't rolled back like the Gaffer's tape in this location in the test at home. My cruise speeds at 6,000 ft MSL with 2450 RPM were around 165 indicated (that is past the upper end of the TAS window but estimated ~185 kts TAS). I took it of and I this point I am planning to run with no tape on the cowl seams tomorrow.

Bob Axsom

 

[Walt]

I've been following this thread with interest. (I've placed a link to one kind of the tape below and it does not appear to be real expensive. That site also carries the 3M 483 tape.) Thanks.

http://www.cumulus-soaring.com/bowlus.htm

Thought I would try some of this tape on my gear fairings just to clean them up a little. I ordered a few days ago from the above folks and the tape arrived in about 3 days, probably before my check made it to them, I like that

I installed the tape today and it went on easy, I'm hoping to gain a knot or two but even if I don't I like the looks of it. The tape is bright white and matches my paint pretty close and I think it looks better that the gap lines.

 

[Bob Axsom]

Walt I am intrested in your results

If you tape all of the gaps in the landing gear system I am certain you will see a significant increase in speed. To me an increase of a whole knot is a major accomplishment. It may seem like I am making more of this than it deserves but in my little world finding 2.6 knots is cause for celebration. I suspect most of this comes from the upper intersection fairings that appear to scoop the air in, especially the nose gear.

There is fog here in Taylor, Texas this morning but the briefing will be in 1 hour and the race will be flown after the fog burns off.

Bob Axsom

 

[Bob Axsom]

Rocket 100 Follow up

The RV-6A averaged 224+ mph in the 8 turn race called the Rocket 100 at Taylor Texas on 11-20-2010. That is slightly faster than our speed in the straight line east bound 2008 AirVenture Cup race and just 2 mph slower than our speed dash speed at Courtland, Alabama.

I did find that the gaffer's tape started to come loose at the upper end of the nose landing gear strut at the cuff interface but it seems to hold up well otherwise under race conditions. I think this can be solved by better application techniques - I'll work on it.

Now into the annual condition inspection I have removed all of the tape. It came off well with no paint damage.

One curious thing I observed in some locations was a white gummy residue where the gaffer's tape had been. This was a transfer of the adhesive from the tape to the surface it was mounted on. These locations may be associated with applications where the tape loosened in flight. It took a little rubbing with a paper towel and rubbing alcohol but it came off cleanly without too much trouble. In most locations the tape came off cleanly with no residue. Any ideas on the reason for the adhesive transfer in some places and not others?

I have blue 3M 471 tape that may work better but that will have to wait until the 2011 SARL racing season (see www.sportairrace.org Calendar of Events).

I saw Bob Mills multiple tape types in multiple applications before the race but I did not check them out afterward. I would be interested to learn how his applications worked out, especially the clear tape on the cowl fasteners and seams.

Bob Axsom

 

[rvmills]

Bob,

In comparing the 471 to the 483, each has benefit.

The 471 is a bit more robust and seems to stick a little better, while conforming to most compound curves well (and it does it better if applied in warm weather than in cold...you can feel the tape is stiffer when its cold out).

The 483 is thinner (you can kinda see through it) but a little more elastic (just as Rosie said). It worked well and went on easy, but it tore a bit when trying to span larger gaps, where the 471 would span such a gap and hold well. I saw more tearing of the 483 in some spots after the flight than I did with the 471. Each has good applications, though I'd say the 471 may be a bit more versatile and the choice if you're only going to buy one type.

The clear tape has held up well, and is still on the cowl. Only the bitter ends at the bottom has showed a little loosening. Seems to be low or no residue, but when I pull it off all around, we'll see the real story. The heat at the cowl joints is what I'm worried about in terms of residue generation...we'll see. Seems pretty good so far. Slick Cone gave me that tape, and is looking up the maker and type (just got off the phone with him).

In the other areas, my guess is the loosening of the tape and the resulting residue is either from a bit of a dirty surface causing it to be more easily pulled up by the air, or just simply a seam in the tape being caught by the air. Once it starts to come up, it just gets dirtier and gunkier, thus the residue. I try to clean before taping, but its not always super clean...and the start of the race is calling sometimes too, as you know! I also try to take to minimize the bitter end that face forward, and I've also tried cutting any forward facing edges in curves or angles to minimize the flat seams that face forward. Some art, some science!

How you pull up the tape up seems to make a difference in residue too, and I've heard a little heat (blow dryer) helps...haven't tried it yet.

More testing next season, eh Bob!

Cheers,
Bob