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Wingroot seal

rcarsey

Well Known Member
Van's has published an updated PAP today here. The only change was in section G10 where they have you check to make sure you've added the wingroot seal.

In earlier version of the KAI, the language stated that you could defer the seal installation until after painting. However, some (myself included) took this to mean you can go and fly with no seal for a year until you go into the paintshop. That is not the case.

From Support: 'Having a gap between the fuselage and wing skins in some cases can have some undesirable effects on stall characteristics do to this disrupted airflow. For this reason we added the comments regarding having the seals installed."
 
Yikes. I have been flying for almost 250 hrs without the seals. YMMV never had an issue and I have stalled the plane dozens of times
 
I have seal on top side and around "D" section nose. I leave bottom open to allow wing to vent. I have witnessed water dripping from airplane in the hanger when atmospheric conditions in the spring create perfect indoor storm.

Airplane stalls per Van's spec with no adverse tendencies. I have flown S-LSA and flight characteristics are identical...
 
Perhaps the factory has not tested flight without the seals and there is potential for issues.. and because they never tested it, they don't want anyone flying without seals. ...or maybe they experienced issues.. or maybe they experienced issues while certifying for spins (the factory said that was in the works awhile ago). Who knows..

I have 150 hours on it now and my paint date is coming up.. so.. for now, I'll refrain from stalling.
 
Mine has nearly 700 hours on it and does not have seals. I haven't noticed any problems. Maybe I would pick up a couple of knots if I put in the seals. Who knows.
 
I did the acceptance tests and flew my first 20 hours without seals and had no problems. Some wing skins may have tighter gaps than others. Maybe that could account for some having issues .
 
Yup, when I flared the plane would descend fairly rapidly, even when coming in at 60+ kts. A touch of power was needed to slow descent. Issue resolved when wing root seals were installed. My experience, FWIW.
 
Interesting, I usually cut power just before turning base and glide all the way in with a very gentle touch down. If anything, I need to slip a bit to get er down.
No root seals installed for now. I did have glider type on for a while, but pulled at annual CI last year. I haven't notice any difference over the past year.

I now have rubber seals ready to install, on top through leading edge just like Piper J3. My bottom skins are already pretty darn tight (and painted). I'd need to trim to fit the seal. And I just don't see the need
 
I put glider tape on the wing to fuse junction until I paint/wrap the airframe. Flying after that was added it "seemed" like the plane landed a skosh faster and was slightly more slippery. LOL I know, very untechnical observations.
 
I usually cut power just before turning base and glide all the way in with a very gentle touch down. If anything, I need to slip a bit to get er down.

Correct. Even 55 KIAS stabilized power-off approach... the 12 still retains lots of energy in the flair. Air gets compressed in ground effect especially with low wing airplane...

Here is video showing forward slip landing over tall trees on 2100' home strip. Speed over trees is slowed to 55 KIAS, then slip, then speed still needs to be bled off in the flare.

https://youtu.be/CvsuBcV5IZs
 
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Late to the party but with 160 hours on the airframe (no paint or seals) I've never noticed anything strange in any high AOA or low airspeed situation. I also have never flown an airplane easier to land than the RV-12.

That said, just went to Van's to pick up a set of seals and, as of 2/9/22, they are on backorder so....
 
I did just that, I have about 1/8” wing root gap +-, I was very surprised by the change it made, now I can’t be lazy with the numbers ,I must slow it down or else when I get to about 5’ it just sits there.
Stan
 
I did just that, I have about 1/8” wing root gap +-, I was very surprised by the change it made, now I can’t be lazy with the numbers ,I must slow it down or else when I get to about 5’ it just sits there.
Stan

Adding wheel pants will have a similar effect.
 
let me see if I've got this right... closing 1/8" wing root gap and adding wheeling fairings causes RV-12 to stay in prolonged ground effect when landing?
 
let me see if I've got this right... closing 1/8" wing root gap and adding wheeling fairings causes RV-12 to stay in prolonged ground effect when landing?

Wheel pants affect your approach speed, usually higher at the same throttle settings, also your descent speed is higher. Plane is more aerodynamic, less drag with them.

Higher approach and flare speed will cause prolonged ground effect.

It is noticeable, even I, when a student pilot, noticed it, when I put my wheel pants back on. Didn't want to damage them learning to land, so I removed them for a bit. It's when I put them back on, I noticed the difference. Plane just didn't want to behave the same, it tended to glide further.
 
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I've flown with / without wing root seals and w / wo wheel fairings and at 55kts on final, the decent rate is same either way. Wheel fairings look nice but do very little at RV-12 speeds especially slowed to half cruise speed on final. Plane stays in ground affect "pays off" same either way.
 
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