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Buckaroo

Glider tape question?

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My tape is getting rough lately so I pulled some off the stabilator top. The rest will be replaced when I get the tape.

Question: If one we’re to remove all the tape would stall speed or handling in general change significantly?

I’m mainly interested in stall speed! Also has anyone tested the effect on cruise speed?

 Thanks 

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1 hour ago, Roger Lee said:

No Change.

Do most you see use tape? I’m tempted to clean it off but not sure if it will look “gappy” without it!

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I use tape. Kind of ugly without it. Also There are a couple variations in how the taping was done on the CTSW. Some have the Mylar strip on top with nothing on the bottom. Others have the Mylar on the bottom with tape on the top.

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Buck,

When Roger said, "No Change" he actually meant, "No perceptible change" - nothing you're going to notice. It would take a well-instrumented, long-term statistical analysis to measure any difference.

But wing tape will reduce stall speed, increase climb rate, increase airspeed at any given prop rpm, and reduce fuel consumption at any given airspeed... but not by very much. My guess - and this is really just a guess - is less than 0.25% better performance - less than a gallon of fuel saved every hundred hours?

The gap between the wing and fuselage allows the high-pressure air underneath the wing to leak through to the top surface. Without a comparable drag reduction, this reduces the effective wing area by something close to the width of the gap - perhaps a bit more due to lateral flow into the gap, or a bit less due to restrictions in the air flow through the gap. “Ah,” you say, “My gap is only about 1/32” on each side, which is 30 times less than 0.25% of the span.” Yes, but the real problem comes on top of the wing where the higher-pressure air is injected into the airstream causing interference drag and turbulence.

You said it when you called it "Glider tape". The latest generation of competition sailplanes costs between $150K and $250K. The pilots buying these ships are expecting maybe 2-4% better performance, 1 or 2 L/D points. Meanwhile, a roll of 3M white vinyl electrical tape costs a couple dollars at Home Depot. I have never seen a competition sailplane pilot who didn't tape his wings before flight, even when he wasn't in a contest.

Tom mentions taping one side. Indeed, you can probably achieve the vast majority of the benefit with half as much tape. Again though, a sailplane pilot is never going to do this.

Mike Koerner

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I always tape wing roots and the top and bottom of the trim tab and along the seam of the under fin.

The tape has function, but not anything you could feel by affecting the aircraft characteristics.

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1 hour ago, Mike Koerner said:

Buck,

When Roger said, "No Change" he actually meant, "No perceptible change" - nothing you're going to notice. It would take a well-instrumented, long-term statistical analysis to measure any difference.

But wing tape will reduce stall speed, increase climb rate, increase airspeed at any given prop rpm, and reduce fuel consumption at any given airspeed... but not by very much. My guess - and this is really just a guess - is less than 0.25% better performance - less than a gallon of fuel saved every hundred hours?

The gap between the wing and fuselage allows the high-pressure air underneath the wing to leak through to the top surface. Without a comparable drag reduction, this reduces the effective wing area by something close to the width of the gap - perhaps a bit more due to lateral flow into the gap, or a bit less due to restrictions in the air flow through the gap. “Ah,” you say, “My gap is only about 1/32” on each side, which is 30 times less than 0.25% of the span.” Yes, but the real problem comes on top of the wing where the higher-pressure air is injected into the airstream causing interference drag and turbulence.

You said it when you called it "Glider tape". The latest generation of competition sailplanes costs between $150K and $250K. The pilots buying these ships are expecting maybe 2-4% better performance, 1 or 2 L/D points. Meanwhile, a roll of 3M white vinyl electrical tape costs a couple dollars at Home Depot. I have never seen a competition sailplane pilot who didn't tape his wings before flight, even when he wasn't in a contest.

Tom mentions taping one side. Indeed, you can probably achieve the vast majority of the benefit with half as much tape. Again though, a sailplane pilot is never going to do this.

Mike Koerner

Mike great response! I’m kind of a mechanical kind of guy who appreciates seeing hinges, wing fuselage fitting without cheap tape etc. If no tape is as effective I’m in it for the natural build fit and look. 

I may change my opinion from others offering their views!🤔

i tend to like to keep things OEM and simple!

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.25 % improvement is a waste of time and money plus hiding hinges and anything OEM is for me counter productive! 

I do see what are I think inspection ports taped. I think these should remain covered. Am I correct in those assumptions?

 Thanks 

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Wing roots have no real inspection and the tape on the stab keeps out dust, dirt and water and may a crawly thing or two. :)

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35 minutes ago, Roger Lee said:

Wing roots have no real inspection and the tape on the stab keeps out dust, dirt and water and may a crawly thing or two. :)

I was kinda thinking the positive side of taping is to keep crap out of the holes and orifices! For me I like seeing goodness during preflight! You know linkages and hinges etc! 

I’m finished with tape!😁

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Why does taping bother you? When I apply it it's easily good for 2-3 years. Taping the wing roots take about 10 min. on each wing which includes cleaning the tape area first. Taping the top trim tab takes about 15 min.

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20 minutes ago, Tom Baker said:

At a minimum you need the tape that was applied at the factory, unless you have an approval to remove it.

What areas are those?

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50 minutes ago, Roger Lee said:

Why does taping bother you? When I apply it it's easily good for 2-3 years. Taping the wing roots take about 10 min. on each wing which includes cleaning the tape area first. Taping the top trim tab takes about 15 min.

I’m really referring to the rear of the plane (stab and along the fuselage. My wings are still taped. Probably will keep that. It has nothing to do with time or money. 

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The trim tab tape should last 2-3 years to. If you apply it wrong it will split or come off. I put 1" Bolus tape on the top and bottom of my 200^ SW trim tab. It never cracked or came off. Every few years I would change it.

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4 minutes ago, Roger Lee said:

The trim tab tape should last 2-3 years to. If you apply it wrong it will split or come off. I put 1" Bolus tape on the top and bottom of my 200^ SW trim tab. It never cracked or came off. Every few years I would change it.

Yes I’ve read your technique of having the tab down when applying so it relaxes when it comes up and visa versa on the bottom. 

Ill probably put it back after I get tired of the gap.🤔

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I only tape the tops of my wings, I can never get the tape to sit well across the bottom gaps with the side of the fuselage so close.  Maybe I'll try again, but it's always frustrating.  

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6 hours ago, FlyingMonkey said:

I only tape the tops of my wings, I can never get the tape to sit well across the bottom gaps with the side of the fuselage so close.  Maybe I'll try again, but it's always frustrating.  

On the bottom I try and get the outside edge of the tape on the wing in position rolling it into place while pushing it over to the fuselage and down the side.

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I took all the tape off mine with the exception of the wings. Looks cleaner to me! 

Why tape the bottoms if it makes no difference in performance? No one see’s the bottom. 

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BTW, on the subject of tape. I bought some from Wings and Wheels, and I can confirm that I prefer Bowlus tape over what I bought.

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What is the purpose of the tape on top of the stabilator?  I removed mine yesterday because it was bubbling and looked bad.  After I removed the tape and glue, its just a smooth surface underneath.  There is no gap to seal or keep clean under the tape.  I don't see why I should put more tape back there.

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1 hour ago, Andy A said:

What is the purpose of the tape on top of the stabilator?  I removed mine yesterday because it was bubbling and looked bad.  After I removed the tape and glue, its just a smooth surface underneath.  There is no gap to seal or keep clean under the tape.  I don't see why I should put more tape back there.

I’m with you Andy! I hate the look of important things like stabs looking like tape holding things together!😱😂

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12 hours ago, Andy A said:

What is the purpose of the tape on top of the stabilator?  I removed mine yesterday because it was bubbling and looked bad.  After I removed the tape and glue, its just a smooth surface underneath.  There is no gap to seal or keep clean under the tape.  I don't see why I should put more tape back there.

Ahh, CTLS. The tape is to help keep the paint from cracking on the elastic hinge. If you use Bowlus tape, and put it on with some care in the application it looks just fine. If you do a poor job of application it looks hideous.

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