VG's and gap seal question!

C

Chic

New member
I would like to hear the opinions of owners out there with gap seals and VG's on their Citabrias, both pro and con. What I would like to know if they have seen a noticeable change in the way the aircraft performs and handles with these items. I have heard that gap seals can improve the cruise up to 10 mph and VG's can shorten the take off length and smooth out the ride in choppy air.....is this stuff true or is it mostly old wives tales? Thanks in advance
Chic
 
I'd be interested in those thoughts also.....especially gap seals and what's used for them. Thanks!
Jim
 
noticed no speed improvment, they do make i nice place for snow and ice to collect :? (gap seals that is) removed them and noticed nothing,
 
Chic,

VG's are a great thing, and will get you off the ground quicker. More noticably though, you'll have better handling through the low end speed, mainly in the Ailerons. Some airplanes don't work well with VG's, things like C172's, C180's but the Aeronca/Bellanca/Champion work nicely with them. Cons.... you will have to pay a little more attention when washing the wings so you don't knock them off.

I've run a gap seal on the elevators of my Champ, and think there is a little improvement in handling. Honestly, VG's would do the same I suspect. What I could do was get the tail flying almost immediatly, and seemed to have a little more responce. More speed???? I doubt it. Maybe on a 'go-fast' like a Columbia or Cirrus, but it won't do anything noticable on a Citabria. There's simply too much aerodynamic drag to overcome.

nkh
 
Nathan, thanks for the input. What did you use for gap seals? What can they be made of? Chic
 
Chic, I used a piece of 2" Clear Packing tape on the bottom side. Worked good until I tried peelling it off, then it wanted to take paint with it. Understand though, my Champ was a bit of a dog, and the paint was coming off A LOT in other places. Others may not have that problem. Some people use a piece of Fabic glued between the 2 surfaces. That works fine until you have to remove an elevator.

Think long and hard before you try something like this. The FAA (and certainly Cali FAA) probably wouldn't appreciate such a mod without the propper paperwork.

nkh
 
Realize that Citabrias have a sort of welded in gap seal on the elevator. You will only be spanning a gap of 1/8 inch or so. I suppose you could seal the rudder. I doubt you will see a whole lot of change.

I highly recommend NOT sealing the ailerons. Our force measurements done on the 8GCBC back in 1991 shown that the gap seal actually makes things slightly worse. The Frize Aileron needs to dip its nose into the airstream and duct it over the top. A gap blocks this. The 'ducting' was so inefficient that it was not critical however. Thus, the conclusion was: Aileron Gap Cover = Weight, Time, Money that does nothing.

As for VG's
They will reduce your stall and take off roll by an amount small enough to not notice a thing. hehe. They are optional equipment on new planes, doesn't change the performace a bit. However, if its low speed handling that you need, then look no further. They improve aileron control at stall greatly and they almost eliminate the elevator stick buffet from the flap downwash.
 
Excellent post and information Jerry. I have a friend that did the VG thing to his plane and swears by it but I'm a bit skeptical and haven't and most likely won't spend the money now.
Thanks GB
 
GB,

When I bought my Champ it already had VG's installed. I have never flown it or any other Champ so I couldn't tell you how well they work. I will say that the man that signed me off for flying it was impressed. We had a hard tim getting it to stall and it has great aileron authority while just mushing along. I do have an 0-235 in it so that may help also.
When I get back to MN we'll have to meet up and maybe I'll let you try it to see what you think. I am very low time so my view on how well they work would be neglegible.

Keith
 
Hi Keith that sounds like a good idea, I'm 90 miles or less from Park Rapids so that would be a nice flt. :D :) :lol: :wink:
And it would be interesting to fly 2 Champs one with and one with out.
GB
 
The extra controlability can give you the feel of extra performance.
But then, thats not a bad thing now, is it? :lol:
 
GB,

I'll be back in MN on the 12th of April. So anytime after that we'll have to get together. I guess my furnace went out in my house during that cold spell so I have a mess and a few things that may need repair before I do any playing. I also want to get the floats put on the Champ and get my Seaplane rating this summer. As long as I can find a place nearby to dock it.

My email is im_planecrazy at yahoo dot com. I'm not sure if I will have the same ph number as last year. I'll let you know when I get the phone hooked back up.

Keith
 
I don't have VG's on my 7GCBC, but when I am out practicing stalls, I still have a helluva time trying to make it stall fully. Having learned to fly in a '43 T-Craft L2M that acted like a rock when stalled, the Citabria seems nearly unstallable to me.

It also takes off in a very short distance too without VG's. How much legnth are we talking about the VG's saving in terms of takeoff? Unless we are talking about turning our Citabria's into helicopters, does anyone find that they really let them get into or out of a strip they otherwise couldn't have?

Joe.
 
if you want a real improvment get the crosswinds stol :D
not to mention getting your wing covers on and off with VG's :evil:
 
Joe, if your Citabria power on stalled at 35 without VG's, installing them might gain you 4-5 mph (30 with VG's). That might equal 50-75 feet of runway. Not really earth shattering numbers, but very significant when it comes to handling. Get a Aeronca/Champion down to 40-45 on approach and the stick get REAL mushy. VG's will dang near eliminate the mushy-ness, mainly in the ailerons. Which is REALLY nice when it's gusty. Long story short, VG's make me feel more confortable at slower speeds; allowing me to Takeoff / Land slower and shorter.

All things considered, I'm not one to put "gadets" on my airplanes. Usually they don't work or just add unecessary weight. But when I finish my wings, they'll have VG's cause they work, period.

One more thing about Gap Seals.... I tried it on the rudder and did not like the results. It made the rudder feel 'over ballanced'; it reduced the rudder pressure needed and felt like it gave less feedback. The only thing positive I can say about it; when doing a full deflection slip, there wasn't any buffetting on the tail. Normally (on my plane) when doing full deflection slips, the rudder would create a buffet from stalling(?) and you could feel it all through the airplane until you let off the slip just a little. It would be a good thing if you're into Acro, but not for a pleasure flyer (IMHO). Personally I like how the rudder feels.

nkh
 
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