Page 1 of 2 12 LastLast
Results 1 to 40 of 43

Thread: Extended upper leading edge skins

  1. #1

    Join Date
    Oct 2011
    Posts
    71
    Post Thanks / Like

    Extended upper leading edge skins

    I'm looking for folks wisdom or reason, why cub builders are extending the upper surface leading edge skins...I've heard why but so far am not buying it. But...well known, experienced builders are doing it, but so far I've not heard a credible answer....

  2. #2
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    10,407
    Post Thanks / Like
    7 lbs per pair of wings. .020. Covers up ugly ribs also


    Sent from my iPhone using SuperCub.Org

  3. #3

    Join Date
    Oct 2012
    Posts
    4,637
    Post Thanks / Like
    Quote Originally Posted by flywhatever View Post
    I'm looking for folks wisdom or reason, why cub builders are extending the upper surface leading edge skins... I've heard why but so far am not buying it.
    What is it you aren't buying?

  4. #4
    Bill Rusk's Avatar
    Join Date
    Jan 2003
    Location
    Spokane Felts Field, WA/Poplar Grove, (Chicago) IL
    Posts
    5,233
    Post Thanks / Like
    It is my understanding that they don’t provide any difference. Other than adding weight. According to John Roncz, probably the world’s premier airfoil engineer and designer, they don’t work. According to a conversation I had with him there is no added benefit, aerodynamically, whatsoever.
    There are quite a few “old wives tales” in the bush flying community.
    Sorting fact from fiction can be a challenge.



    Bill
    Last edited by Bill Rusk; 11-02-2019 at 04:48 PM.
    Very Blessed.
    Likes Hardtailjohn liked this post

  5. #5

    Join Date
    Feb 2002
    Location
    Alaska/NE Washington
    Posts
    364
    Post Thanks / Like
    My understanding is it was started when guys were concerned with scalloping, of fabric, between the ribs. The extended metal is supposed to keep the airfoil true as opposed to the belief fabric would somehow would not in all conditions. Improperly applied and shrank fabric can cause ballooning between the ribs reducing the efficency of the airfoil. Properly applied the fabric pops level with the wing rib as soon as the wing gets some air moving over the top. One does need to be careful while sweeping snow off the wings between the ribs because denting the trailing edge will show. Some will brake an edge on the trailing side for strength
    Likes flywhatever, cubflier, Hardtailjohn liked this post

  6. #6

    Join Date
    Feb 2002
    Location
    don
    Posts
    699
    Post Thanks / Like
    Have extended leading edges. I think they increased my cruiser speed 10kts! Decreased stall speed the same!
    Believe it or not!not!
    Likes mike mcs repair, CharlieN liked this post

  7. #7

    Join Date
    Oct 2012
    Posts
    4,637
    Post Thanks / Like
    I was indifferent about extending the LE back until I saw a picture of the fabric puffing up above the ribs of a familiar plane on short final nearing touch down. The contour of the top of the wing changed at the most critical moment of flight. I don't see any reason to let that occur if I can prevent it.
    Likes dgapilot, mike mcs repair liked this post

  8. #8
    CenterHillAg's Avatar
    Join Date
    Aug 2013
    Location
    Texas Coast
    Posts
    87
    Post Thanks / Like
    I have no opinion on extending the leading edges, but cleaning up the dents and working over the leading edge on my ag plane made a huge difference in handling and performance. If I was determined to add 7 lbs to the wings, I’d look at thicker leading edges vs extending them.
    Likes dgapilot, Brandsman liked this post

  9. #9

    Join Date
    Oct 2011
    Posts
    71
    Post Thanks / Like
    Best answer so far Bill...you and I are on the same page...

  10. #10

    Join Date
    Oct 2011
    Posts
    71
    Post Thanks / Like
    10kts?!!!

  11. #11

    Join Date
    Jan 2003
    Location
    nd
    Posts
    3,243
    Post Thanks / Like
    Quote Originally Posted by stewartb View Post
    I was indifferent about extending the LE back until I saw a picture of the fabric puffing up above the ribs of a familiar plane on short final nearing touch down. The contour of the top of the wing changed at the most critical moment of flight. I don't see any reason to let that occur if I can prevent it.
    is there a way to find this picture?
    Hi. I finally found the picture that says it all about extended leading edges. You have to d/click and blow it up to see what I mean. It is posted on S.C. Galore, Page 19, Item #1. or picture #163. A picture is worth 3,000 words. Jerry Burr

  12. #12

    Join Date
    Oct 2012
    Posts
    4,637
    Post Thanks / Like
    I remember the pic Jerry referenced. It was a Cub in normal flight and had reverse scalloping. The photo I'm referring to was from an overhead video of a slat winged Cub. The fabric is unremarkable until the moment ahead of touch down when it clearly lifts. Would it affect lift? Can't say, but it can't help. Would it affect durability? It must. How many cycles of that pulling on the rib lacing can it take? I saw this vid after Mike and I extended my metal. Where this other plane's fabric changed is exactly where my extended metal is.

    I've got friends who've used fabric bands and carbon fiber bands to combat the scalloping. I couldn't care less about the scalloping. I'm focused on the fabric lifting. I have a big, heavy Cub hanging under very high lift wings. What Piper did isn't necessarily the right thing for evolved Cubs.
    Thanks barrow pilot thanked for this post

  13. #13
    BC12D-4-85's Avatar
    Join Date
    Feb 2016
    Location
    Fairbanks, AK.
    Posts
    1,629
    Post Thanks / Like
    Fabric covering moves up and down in flight. Under normal load or climb the top and bottom wing coverings move up; in a negative gust they move down. In a stall the lower wing cover is pushed up while the upper cover "probably" un-scallops from rear wing to front as airflow separates and lift is lost. The horizontal tail top cover is usually pushed down in flight to offset aircraft weight forward of the center of wing lift. Look at the pics below. There's more scalloping at the wing root than tip which reflects normal span wise lift distribution.

    We've all seen some of that (hopefully). The tighter the fabric shrink or the warmer the air the less the movement in my experience. The lower covering moves lots in real cold. Unless one surface moves more than the other lift should remain relatively equal.

    Speeds may change if the airfoil changes basic shape. I'll not argue for or against any benefit in cruise by reducing scalloping unless there's added drag to reduce or extra lift for the tail to correct for. In a pre-stall high AOA the leading edge is carrying most of the load. I'd not want to create sudden unexpected flow separation by radically changing upper wing shape.

    Gary
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	171297-13188127.jpg 
Views:	136 
Size:	47.8 KB 
ID:	45417   Click image for larger version. 

Name:	FHMFARQ5WUJGL2RBSJXSQWUVSE.jpg 
Views:	132 
Size:	37.7 KB 
ID:	45418  
    Likes L18C-95 liked this post

  14. #14
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    9,355
    Post Thanks / Like
    Quote Originally Posted by pak View Post
    My understanding is it was started when guys were concerned with scalloping, of fabric, between the ribs. The extended metal is supposed to keep the airfoil true as opposed to the belief fabric would somehow would not in all conditions. Improperly applied and shrank fabric can cause ballooning between the ribs reducing the efficiency of the airfoil. Properly applied the fabric pops level with the wing rib as soon as the wing gets some air moving over the top.
    All fabric will rise between the ribs whether applied properly or poorly. The question should be to what amount does it rise? If you ever flew in a fabric covered low wing airplane or closely along side a high wing airplane this would be obvious.

    Quote Originally Posted by Bill Rusk View Post
    It is my understanding that they don’t provide any difference. Other than adding weight. According to John Roncz, probably the world’s premier airfoil engineer and designer, they don’t work. According to a conversation I had with him there is no added benefit, aerodynamically, whatsoever.
    There are quite a few “old wives tales” in the bush flying community.
    Sorting fact from fiction can be a challenge.

    Bill
    I have a great deal of respect for John Roncz and his work with aerodynamics, particularly airfoils. I envy Bill for having had an opportunity to have a discussion with him. The very early airplanes only had a small straight edge for their leading edges which resulted in drawn in scalloping over the entire wing. Along the way this evolved into what we know as a leading edge. We all know that the shape of the leading edge dictates what the airflow does as it moves aft. What determines at what point this leading edge ceases to be effective to the flow of the air as it moves aft? This would be different with different airfoil shapes. On those early wings, at what point did the inward scalloping transition to an outward pulling scallop? Where is this transition on a stock Cub wing? Anyone, as I have no clue? As a general rule of thumb it is my impression that the aft edge of the leading edge skin should be located just aft of the thickest point of the airfoil shape. This would ensure a constant airfoil shape over the entire wing. Any less would mean a loss of available efficiency.

    Many here have installed VGs on the leading edges of their wings. Do they know Why? VGs effect the airflow as it moves aft across the wing. What happens when the trialing edge of the leading edge skin is moved aft a little bit? A little more? Will this effect your VG function?

    We all know that a stall begins with the airflow separation at the wing trailing edge and then progresses forward. This separation is determined by the shape of the flow of the air starting at the leading edge. Somewhere as the air moves aft the shape of the upper camber of the airfoil ceases to make much difference. It seems to me that this is where the trailing edge of the leading edge ought to be.

    To be able to accurately answer the question of where should the trailing edge of the leading edge be located, we would have to have access to a computer program which would act as a visual wind tunnel with streamlines.

    The wings on my Cub came with the extended leading edge skin. I'd have to measure it to tell you how much. I covered the entire leading edge with a thin layer of felt to make the rivets almost disappear producing a smooth leading edge over the entire wing. I don't know whether the felt helped or not. It does look nice. I can say that the stall characteristics and the ability to fly at a very low speed are excellent. This wing is clean with no VGs or other devices.
    N1PA
    Likes CharlieN, Brandsman, TurboBeaver liked this post

  15. #15
    BC12D-4-85's Avatar
    Join Date
    Feb 2016
    Location
    Fairbanks, AK.
    Posts
    1,629
    Post Thanks / Like
    https://www.supercub.org/forum/showt...-rib-stitching

    Some earlier discussion and in #17 the linked NACA Tech report from 1927. Time flies.

    Gary

  16. #16

    Join Date
    Oct 2011
    Posts
    71
    Post Thanks / Like
    Here it is: http://ntrs.nasa.gov/archive/nasa/ca...1993087647.pdf
    Some good discussions from back in 2009. Thx, Gary!

    Quote Originally Posted by BC12D-4-85 View Post
    https://www.supercub.org/forum/showt...-rib-stitching

    Some earlier discussion and in #17 the linked NACA Tech report from 1927. Time flies.

    Gary

  17. #17

    Join Date
    Oct 2012
    Posts
    4,637
    Post Thanks / Like
    Click image for larger version. 

Name:	IMG_2547.JPG 
Views:	85 
Size:	663.0 KB 
ID:	45430

    Click image for larger version. 

Name:	IMG_2553.JPG 
Views:	72 
Size:	342.3 KB 
ID:	45432

    Click image for larger version. 

Name:	IMG_2555.JPG 
Views:	70 
Size:	321.8 KB 
ID:	45431


    Sent from my iPhone using SuperCub.Org mobile app

  18. #18
    BC12D-4-85's Avatar
    Join Date
    Feb 2016
    Location
    Fairbanks, AK.
    Posts
    1,629
    Post Thanks / Like
    Somebody should stick a camera on the Cub tail and/or wing lifting rings then go document the upper surface in flight. Might answer some of these questions.

    Here's how they used to do it by poking their head above the skylight and looking: https://ntrs.nasa.gov/archive/nasa/c...9930083935.pdf

    Gary

  19. #19

    Join Date
    Oct 2012
    Posts
    4,637
    Post Thanks / Like
    Somebody should take some drone footage at a big stol contest. Get a bigger sample group in a standard setting.

  20. #20
    Steve Pierce's Avatar
    Join Date
    Mar 2002
    Location
    Graham, TX
    Posts
    18,741
    Post Thanks / Like
    I am curious about the scalloping on the latest versions of fabric when the wings are covered with the blanket method. The last 2 revisions of fabric seem to tighten up long ways more the previous versions with not much if any scalloping. Wll have to get some air to air photos to see.
    Steve Pierce

    Everybody is ignorant, only on different subjects.
    Will Rogers

  21. #21
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    9,355
    Post Thanks / Like
    Quote Originally Posted by Steve Pierce View Post
    I am curious about the scalloping on the latest versions of fabric when the wings are covered with the blanket method. The last 2 revisions of fabric seem to tighten up long ways more the previous versions with not much if any scalloping. Will have to get some air to air photos to see.
    I don't know what sequence you use when you shrink the Dacron. I've found that when you do your initial shrinking over the ribs alone, this shrinks the fabric span-wise without being able to pull down between the ribs. When you shrink in the center of the bays first the fabric tightens between the leading edge and the trailing edge first pulling the fabric down. The first method maintains as straight a surface as possible. The second method make scallops which can never be raised.
    N1PA
    Likes flywhatever liked this post

  22. #22
    Bill Rusk's Avatar
    Join Date
    Jan 2003
    Location
    Spokane Felts Field, WA/Poplar Grove, (Chicago) IL
    Posts
    5,233
    Post Thanks / Like
    I was not able to make the NACA study link work. Here it is again.

    https://ntrs.nasa.gov/archive/nasa/c...9930081179.pdf

    Click image for larger version. 

Name:	Screen Shot 2019-11-03 at 6.06.56 PM.png 
Views:	799 
Size:	271.4 KB 
ID:	45442."

    Click image for larger version. 

Name:	Screen Shot 2019-11-03 at 6.08.21 PM.png 
Views:	798 
Size:	384.5 KB 
ID:	45443


    "The results of these tests indicate that the usual sagging of the wing covering between ribs has a very small effect on the aerodynamic characteristics of an airfoil"


    Bill



    Very Blessed.
    Likes flywhatever, Hardtailjohn liked this post

  23. #23

    Join Date
    Jan 2003
    Location
    nd
    Posts
    3,243
    Post Thanks / Like
    Quote Originally Posted by Bill Rusk View Post
    I was not able to make the NACA study link work. Here it is again.

    https://ntrs.nasa.gov/archive/nasa/c...9930081179.pdf

    Click image for larger version. 

Name:	Screen Shot 2019-11-03 at 6.06.56 PM.png 
Views:	799 
Size:	271.4 KB 
ID:	45442."

    Click image for larger version. 

Name:	Screen Shot 2019-11-03 at 6.08.21 PM.png 
Views:	798 
Size:	384.5 KB 
ID:	45443


    "The results of these tests indicate that the usual sagging of the wing covering between ribs has a very small effect on the aerodynamic characteristics of an airfoil"


    Bill



    ???
    Bill, i think the concern is with the fabric being able to rise above the top surface of the rib more than staying below the surface. or the wing being thicker than the rib profile, how will it effect things, so if the fabric is down between the ribs will it be able to be sucked up that much over the top of the ribs in between bays?? a video camera would tell if thats happening. ive never looked or thought about it where some of these guys have. i remember Darrell Starr showing how his engine cowling puffed out in flight, and air getting by his engine baffles. always thought that was weird.
    Last edited by tempdoug; 11-03-2019 at 08:51 PM.

  24. #24
    Bill Rusk's Avatar
    Join Date
    Jan 2003
    Location
    Spokane Felts Field, WA/Poplar Grove, (Chicago) IL
    Posts
    5,233
    Post Thanks / Like
    I don't think it will have any affect at low AOA like cruise, at high AOA the air is only attached at the very leading edge so even if it billowed a little it is in dead air and will have no affect. I'm sure you can find a picture of someone with very loose fabric, or zero rib stitching, with a huge billow and interpret that to mean whatever you want. The reality is this is just not an issue.....IN MY OPINION, based on the research I did before I removed the extended LE that came on my Smithcub.

    Best regards

    Bill
    Very Blessed.

  25. #25

    Join Date
    Jan 2003
    Location
    nd
    Posts
    3,243
    Post Thanks / Like
    this picture in garys post #13 really shows it.

  26. #26
    BC12D-4-85's Avatar
    Join Date
    Feb 2016
    Location
    Fairbanks, AK.
    Posts
    1,629
    Post Thanks / Like
    Any one know if Piper changed the LE on the PA-25 Pawnee? It might be interesting to find out as they would have had a choice if there was a chance for better performance. Plus they could watch the upper fabric when bored.

    Gary

  27. #27
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    9,355
    Post Thanks / Like
    Quote Originally Posted by Bill Rusk View Post
    I was not able to make the NACA study link work. Here it is again.

    https://ntrs.nasa.gov/archive/nasa/c...9930081179.pdf

    "The results of these tests indicate that the usual sagging of the wing covering between ribs has a very small effect on the aerodynamic characteristics of an airfoil"


    Bill
    Bill, I read this report and did note the conclusion as you stated. The original question was asking about extending the leading edge aft of Piper's original location. This NACA report does not discuss that question at all, only the sag and lift between the ribs. Moving the leading edge aft will effect the shape of that sag. If that NACA report had discussed the differences between a leading edge skin of an unknown dimension and no leading edge skin at all, then we may have received an answer to the original question.
    N1PA
    Likes mike mcs repair liked this post

  28. #28
    Gordon Misch's Avatar
    Join Date
    Dec 2003
    Location
    Toledo, Wa (KTDO)
    Posts
    3,358
    Post Thanks / Like
    I put this post in the wrong thread - the one about rib stitching extended leading edges. I'm sorry; it really only belongs here, but it's duplicated.

    My -12 today, in steady-state level flight. The sun is low, so it's easy to see the contours on the top of the wing when zoomed in. The fabric is very slightly convex. Maybe 1/4" Maybe? I would argue that the fabric scallops we see on the ground are a non-issue. I did a hard turn (2 g?) to the left and Andrew, the photographer in his -12, saw very little if any change in the fabric contour from that in level flight.
    Click image for larger version. 

Name:	Nov 4, 2019 over Longview, Wa.   Photo by Andrew C..jpeg 
Views:	92 
Size:	48.8 KB 
ID:	45477
    Gordon

    N4328M KTDO
    My SPOT: tinyurl.com/N4328M (case sensitive)
    Likes mike mcs repair, Hardtailjohn liked this post

  29. #29
    gpepperd's Avatar
    Join Date
    Aug 2005
    Location
    Wasilla, Alaska
    Posts
    215
    Post Thanks / Like
    You guys can go ahead and tell yourselves that scallop doesn't matter all you want. My experience and farmer sense tells me otherwise. The issue to me is reduced airfoil profile between the ribs that trends towards a cruise profile rather than lift. Compare a Cessna airfoil to a Beaver for high lift vs. cruise. Ballooning fabric at 40-95 is not the same as having the full airfoil at 25 when you're trying to get airborne in the shortest distance. MHO.
    Good judgment comes from experience, and a lot of
    that comes from bad judgment. will rodgers

    "Anyone who would give up liberty for safety deserves neither" Ben Franklin

  30. #30
    aviationinfo's Avatar
    Join Date
    Feb 2007
    Location
    Southwest WA
    Posts
    718
    Post Thanks / Like
    I think we are debating the difference between shades of gray here. Seems to me that the airfoil between the ribs on fabric covered single engine airplanes is going to maintain the same airfoil in proportion whether it sags or not. And the amount of sag or expansion is truly minimal. I’ll wager that any differences in lift (between ribs as opposed to at the rib itself) are hardly worth measuring, if they’re even measurable.

    Having said that, it sure was fun working the field experiment with Gordon! We have found a new excuse for our wives: “Hon I’m going flying today—Science demands it!”
    Likes mike mcs repair, Hardtailjohn liked this post

  31. #31
    skywagon8a's Avatar
    Join Date
    Mar 2008
    Location
    SE Mass
    Posts
    9,355
    Post Thanks / Like
    This thread has drifted away from the original question about extended leading edges. IF the leading edge was only 1", the shape of the airfoil in the center of a bay behind the LE would be different than the shape of the airfoil at the ribs. These two airfoils would have different characteristics. The airfoil in the center would be slightly variable due to the ballooning effect of the fabric. According to experts this would be minimal. However, if the leading edge was extended back to the maximum airfoil thickness location, the characteristics would be consistent across the entire span.

    Now if there was no difference between the short and the long leading edge, there should be no difference in performance between like airplanes with thick or thin airfoils. Thin or flatter airfoils tend towards efficiency at high speeds. Thicker airfoils tend towards increased lift at lower speeds. Do you want your Cubs to be efficient at low speeds or higher speeds? How would your Cubs perform if the entire wing's airfoil was the same as that with a short leading edge having that in the center of the bay shape?

    Personally I will take the full sized airfoil over the entire span.
    N1PA

  32. #32

    Join Date
    Oct 2012
    Posts
    4,637
    Post Thanks / Like
    Got lifting eyes on your planes? It took about 15 minutes to make a simple squeeze plate camera mount for my lifting rings. It uses a 1" Ram ball mount if any local guys would like to borrow it. Point a camera at your wing tops and go see what they do.

    Click image for larger version. 

Name:	IMG_0007.JPG 
Views:	53 
Size:	603.5 KB 
ID:	45486


    Sent from my iPhone using SuperCub.Org mobile app
    Likes BC12D-4-85, CamTom12 liked this post

  33. #33
    TurboBeaver's Avatar
    Join Date
    Jun 2009
    Location
    Northern Maine
    Posts
    695
    Post Thanks / Like
    I am with Greg on this one, regardless of physics theorys, most of the doggyest Cubs I have flown over the years had one single factor ( besides weight) they all had lots of scalloping between ribs......... Imho.

    Sent from my LM-X210 using SuperCub.Org mobile app

  34. #34

    Join Date
    Oct 2012
    Posts
    4,637
    Post Thanks / Like
    The question is at what speed are scallops lifted and how far does the fabric lift? And is it different than fabric lift on a wing with less pronounced scalloping? What factors determine rate and amount of total fabric lift? I’m sure the answer varies by airplane but perhaps a trend can be identified?

    I suspect slats increase the tug on the fabric aft of conventional leading edges. VGs may as well but to a lesser degree. Interesting stuff. Maybe this spring I can get a couple of handfuls of slat wing owners to meet up and do some slow flying with video of the wing tops. That could be interesting.
    Last edited by stewartb; 11-09-2019 at 09:49 AM.
    Likes mike mcs repair liked this post

  35. #35

    Join Date
    Oct 2011
    Posts
    71
    Post Thanks / Like
    A HAH!! Here we go again...reading the Poly Fiber covering book, Page 20-21, there is a section that discusses scalloping. The author says SCALLOPING doesn't present any aerodynamic problems, it's merely a cosmetic issue. They continue to say that Medium fabric results in little or no scalloping. The use of HEAVY fabric creates deeper scalloping than MEDIUM fabric. Since I originally posted this rant I've read that their are folks that used to be concerned with scalloping, hence extended the leading edge, and NOW, have returned to not extending the leading edge, the original concept that scalloping doesn't affect anything to any Nth degree. Just, more food for thought...

  36. #36
    cubpilot2's Avatar
    Join Date
    May 2003
    Location
    Anchorage Alaska
    Posts
    727
    Post Thanks / Like
    2 cents worth. Years ago a friend of mine in Anchorage praised the results of his leading edge extension. He and his best friend flew nearly identical cubs together for years and they were pretty competitive. Being able to fly slower then the other when side by side was one such contest. He said that they were pretty much equal and would both stagger and stall about the same time with equal loads. These were basically stock airplanes and prior to VGs. He recovered his wings and extended the leading edge with no other modifications. He said that after that he could easily fly slower then his buddy who would be stalled out. He believed the airplane even felt more stable when slow. I had no reason to dispute his experience.

    It was his testimony that convinced me to change mine.
    All I can tell you is that mine a very good flying and very stable cub when slow.

    Arguing the effects of scallops is about the same as down wind turns. I don't like big scallops and am very cautious in "down wind turns". I believe in both.

    If I were selling covering material that could produce unsightly scallops and another that doesn't; without specific measurable evidence as to its effect; then I would probably say that it doesn't make a difference either.

  37. #37

    Join Date
    Oct 2011
    Posts
    71
    Post Thanks / Like
    Good answer...
    Quote Originally Posted by cubpilot2 View Post
    2 cents worth. Years ago a friend of mine in Anchorage praised the results of his leading edge extension. He and his best friend flew nearly identical cubs together for years and they were pretty competitive. Being able to fly slower then the other when side by side was one such contest. He said that they were pretty much equal and would both stagger and stall about the same time with equal loads. These were basically stock airplanes and prior to VGs. He recovered his wings and extended the leading edge with no other modifications. He said that after that he could easily fly slower then his buddy who would be stalled out. He believed the airplane even felt more stable when slow. I had no reason to dispute his experience.

    It was his testimony that convinced me to change mine.
    All I can tell you is that mine a very good flying and very stable cub when slow.

    Arguing the effects of scallops is about the same as down wind turns. I don't like big scallops and am very cautious in "down wind turns". I believe in both.

    If I were selling covering material that could produce unsightly scallops and another that doesn't; without specific measurable evidence as to its effect; then I would probably say that it doesn't make a difference either.
    Likes mike mcs repair liked this post

  38. #38

    Join Date
    Jan 2007
    Posts
    1,679
    Post Thanks / Like
    One thing to consider is installation of the extended leaving edge makes for a very stiff wing. If do you have an older fuselage that may be tweaked it can be made to fly straight with rigging. Having extended leading edge can limit the amount of adjustment you can get out of the wing.
    DENNY
    Likes flywhatever liked this post

  39. #39
    www.SkupTech.com mike mcs repair's Avatar
    Join Date
    Aug 2004
    Location
    chugiak AK
    Posts
    10,407
    Post Thanks / Like
    Quote Originally Posted by DENNY View Post
    Having extended leading edge can limit the amount of adjustment you can get out of the wing.
    DENNY
    not an issue...

  40. #40
    Hardtailjohn's Avatar
    Join Date
    Jan 2007
    Location
    Marion, MT
    Posts
    703
    Post Thanks / Like
    Quote Originally Posted by flywhatever View Post
    They continue to say that Medium fabric results in little or no scalloping. The use of HEAVY fabric creates deeper scalloping than MEDIUM fabric. ..

    This I would agree with....and light fabric, double covered produces very very little scallop! (exprimental) It's also going to be less apt to lift...since it's 2 layers....think plywood stiffness.
    John
    Likes pfm liked this post

Similar Threads

  1. Re-installing old leading edge skins
    By Billy-250 in forum Tips and Tricks
    Replies: 14
    Last Post: 03-23-2013, 06:30 PM
  2. Question on making leading edge skins
    By Iflylower in forum Experimental Cubs
    Replies: 27
    Last Post: 01-30-2010, 08:18 PM
  3. Extended leading edge
    By Frenchy in forum Experimental Cubs
    Replies: 2
    Last Post: 02-25-2006, 10:16 PM

Bookmarks

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •