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Thread: Rigging Wipline 2100S to Patrol

  1. #1
    SuperDuper's Avatar
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    Rigging Wipline 2100S to Patrol

    Building a Bearhawk Patrol (2 place) and have a set of Wipline 2100S with PA18 rigging. My experience with float planes is limited to a J-3 with a set of Aqua 1500's cut to fit/STC installation.

    Looking for some insight from those of you with more experience in the area of float installations / modifications.

    Any chance I can use the PA18 rigging without modification? I can post dimensions/layout of the Patrol attachment points if anyone is interested in jumping in on the discussion.

    Pretty sure I will have to make some modification to at least one set of struts, in order to get the right angle of attack. But the first decision is really whether the PA18 rigging is the right starting point or not.

    Real world experience, like 1/4" change in this strut length results in "x" degrees of angle of attack, is along the lines of what I am looking for.

    Thanks in Advance,

    Clayton

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    I found the Clamar float site to be helpful. Resources area and manual
    best of luck. Jeff
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    mvivion's Avatar
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    It’s the relationship between the angle of incidence of the wing relative to the angle of incidence of the floats that you’re ciponcerned about, NOT “angle of attack”.

    cut the rear struts to achieve a one degree positive angle of incidence of the floats. Ie: floats are one degree up from angle of wing. Maybe two.

    MTV

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    Quote Originally Posted by mvivion View Post
    It’s the relationship between the angle of incidence of the wing relative to the angle of incidence of the floats that you’re ciponcerned about, NOT “angle of attack”.

    cut the rear struts to achieve a one degree positive angle of incidence of the floats. Ie: floats are one degree up from angle of wing. Maybe two.

    MTV
    Thanks Mike for reply.
    Sorry about the use of the wrong term. Certainly understand the difference, and in this instance I should be talking about angle of incidence.

    So that I am clear, you are suggesting that I leave the front struts at the current length and adjust the rear strut to achieve 1 (maybe 2) degrees of positive angle of incidence relative to the wing's angle of incidence.

    Considering that the Patrol is probably about 4 inches wider in the fuselage, do you think there would be any issue with the spreader bars being too narrow? Pretty sure that the wide body Cubs use the same spreader bars, but not sure about that. Maybe you or another reader has experience in that area.

    Thanks,

    Clayton

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    Quote Originally Posted by cruzair View Post
    I found the Clamar float site to be helpful. Resources area and manual
    best of luck. Jeff
    You are right - lots of good information

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    Quote Originally Posted by SuperDuper View Post
    Thanks Mike for reply.
    Sorry about the use of the wrong term. Certainly understand the difference, and in this instance I should be talking about angle of incidence.

    So that I am clear, you are suggesting that I leave the front struts at the current length and adjust the rear strut to achieve 1 (maybe 2) degrees of positive angle of incidence relative to the wing's angle of incidence.

    Considering that the Patrol is probably about 4 inches wider in the fuselage, do you think there would be any issue with the spreader bars being too narrow? Pretty sure that the wide body Cubs use the same spreader bars, but not sure about that. Maybe you or another reader has experience in that area.

    Thanks,

    Clayton
    Clayton.
    Your spreader bar width is not an issue for your airplane. However
    you will want to tread carefully with
    the relationship of angle of incidents
    between the top of the floats and the bottom of the wing. Particularly if your
    plane does NOT have flaps. Edo changed the angle significantly on same models as flaps got more common. And more horsepower was added. Lots of early combos like say
    J3 on 1320s will show 5 degrees difference, no flaps n 65hp. That works fine. Check a factory set up on
    a early Citabria on PK 1800s, and its only 2 degrees as Mike suggests. But
    thats 150hp and flaps. This was done for better cruise speeds. But everything is a compromise and take off performance; especially heavy or on a hot day is significantly improved
    with a 5 degrees as compared to 2 degrees. The loss in speed isnt as great as you would think. Approximately 5mph slower on a 135hp Champ with no flaps going from 2/5 degrees. However T/O distances when heavily loaded in flat calm conditions begin to approach half the distance with 5 degrees vs 2 degrees....... So it all about your mission once again. Good luck on your project!
    E

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    skywagon8a's Avatar
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    The book "Design for Flying" by David Thurston has a good chapter on seaplanes. Dave, a former Grumman engineer was one of the designers of the Lake and the Teal amphibians.

    Are your strut to float deck fittings flexible or fixed in the angle that the struts are pointed towards the fuselage? If fixed and your fuselage is a different width than the Cub you may require new float deck fittings. These fittings determine where the other end of the strut lines up with the fuselage.

    EDO calls the angle of incidence of the wing relationship to the floats a "fish mouth opening". The more the mouth is open the bigger the number. This wants to be a positive number. Mike's description appears to be a negative number. The more this mouth is open, the lower the take off speed will be. (Like installing big tires.) Also there will be more cruise drag giving you a lower cruise speed. The "fish mouth" opening angle is a compromise between take off performance and cruise performance. I used about 3-3.5 degrees on my Cub. This angle is determined by the length of the rear strut on tail wheel airplanes. (Nose wheel airplanes would be front strut.) You may find that by making the rear strut to fuselage fitting adjustable that you can tweak this angle. (This would be optional of course.) In use on some airplanes, changing this rear strut dimension by as little as 1/8" makes a noticeable difference in performance. This angle can be tweaked on some floats by placing large washers between the deck fittings and the float tops.

    The angle of incidence of the wing is measured from the chord line of the airfoil. This is not necessarily the same as the bottom of the wing. Check the airfoil on your airplane.

    The "fish mouth" angle is measured between the chord line of the wing and the keel of the floats. The whole purpose of this angle is to set the relationship of the wing to the planing angle of the float bottoms to the water surface. Check the relationship of your keels to the decks of the floats. You may be able to use the decks for measuring purposes if these are parallel.

    You also need to set the relationship of the step to the loaded CG of the airplane. Determine where the vertical and horizontal loaded CG is located. This doesn't need to be precise, just reasonably close. Position the step of the floats 10 degrees aft of this point measured with the plane level. Again this is not precise since we know that the CG moves around in use. It is the starting point, which though testing has been determined to give the best water handling characteristics. The step position is determined by the length of the diagonal strut.

    You may (will) find it helpful to suspend the leveled naked fuselage above the floats for measuring purposes. You may also find it helpful to make a set of fittings out of wood for fitting purposes before machining the aluminum blocks. There are a lot of little angle differences in these fittings. The lefts and rights are mirror images. So that a little twist angle on one fitting will be opposite the one for the other side. The fittings which have two struts connecting may not have the same angles for each strut.

    Landing loads are distributed from the floats to the main landing gear point on the fuselage through a strut from the front of the float and another from the rear of the float joining at the main gear location on the fuselage. This is why you will notice that the diagonal strut angle is different between tricycle and tail wheel airplanes.

    I'm not familiar with the Patrol airplane. Where are you planning to attach your rear struts? That location on the fuselage must be able to transfer the landing loads from the rear strut into the fuselage structure. If you have a steel tube fuselage this should be a tubing cluster being able to spread the loads properly. If an aluminum structure this is also true with a different thought process in designing the reinforcements.
    N1PA
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    SuperDuper's Avatar
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    Quote Originally Posted by TurboBeaver View Post
    Clayton.
    Your spreader bar width is not an issue for your airplane. However
    you will want to tread carefully with
    the relationship of angle of incidents
    between the top of the floats and the bottom of the wing. Particularly if your
    plane does NOT have flaps. Edo changed the angle significantly on same models as flaps got more common. And more horsepower was added. Lots of early combos like say
    J3 on 1320s will show 5 degrees difference, no flaps n 65hp. That works fine. Check a factory set up on
    a early Citabria on PK 1800s, and its only 2 degrees as Mike suggests. But
    thats 150hp and flaps. This was done for better cruise speeds. But everything is a compromise and take off performance; especially heavy or on a hot day is significantly improved
    with a 5 degrees as compared to 2 degrees. The loss in speed isnt as great as you would think. Approximately 5mph slower on a 135hp Champ with no flaps going from 2/5 degrees. However T/O distances when heavily loaded in flat calm conditions begin to approach half the distance with 5 degrees vs 2 degrees....... So it all about your mission once again. Good luck on your project!
    E

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

    Thanks TB

    The information you provided is exactly what I am looking for.
    Regarding the Patrol, it has lots of flaps and 180 HP, so I will start on the lower end of the scale with 2 degrees. I am thinking at this point, that it make most sense to just bolt up everything I have and see what I am starting with.
    The J3 on 1500 Aqua floats that I am flying has certainly illustrated the relationship between weight, density altitude, water conditions, and take off distance. In fact, I am going to double check the angle of incidence on that setup when I make the switch this year. Fortunately I have lots of water to work with here around the house. The Patrol will be making some real cross country trips, so T/O distance will be even more important.

    I appreciate the mission specific elements here, which brings another point to mind. How critical is CG placement relative to the step? Since the Super Cub and Patrol are similar in design, I am guessing (hoping actually) that there would not be a need to bring the floats forward or aft on the Patrol relative to the Super Cub. That would require modification to all of the struts. The Clamar resources the Cruzair mentioned above does have some information on the subject, but I would certainly welcome experience as well.

    Thanks Again,

    Clayton

  9. #9
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    Quote Originally Posted by skywagon8a View Post
    The book "Design for Flying" by David Thurston has a good chapter on seaplanes. Dave, a former Grumman engineer was one of the designers of the Lake and the Teal amphibians.

    Are your strut to float deck fittings flexible or fixed in the angle that the struts are pointed towards the fuselage? If fixed and your fuselage is a different width than the Cub you may require new float deck fittings. These fittings determine where the other end of the strut lines up with the fuselage.

    EDO calls the angle of incidence of the wing relationship to the floats a "fish mouth opening". The more the mouth is open the bigger the number. This wants to be a positive number. Mike's description appears to be a negative number. The more this mouth is open, the lower the take off speed will be. (Like installing big tires.) Also there will be more cruise drag giving you a lower cruise speed. The "fish mouth" opening angle is a compromise between take off performance and cruise performance. I used about 3-3.5 degrees on my Cub. This angle is determined by the length of the rear strut on tail wheel airplanes. (Nose wheel airplanes would be front strut.) You may find that by making the rear strut to fuselage fitting adjustable that you can tweak this angle. (This would be optional of course.) In use on some airplanes, changing this rear strut dimension by as little as 1/8" makes a noticeable difference in performance. This angle can be tweaked on some floats by placing large washers between the deck fittings and the float tops.

    The angle of incidence of the wing is measured from the chord line of the airfoil. This is not necessarily the same as the bottom of the wing. Check the airfoil on your airplane.

    The "fish mouth" angle is measured between the chord line of the wing and the keel of the floats. The whole purpose of this angle is to set the relationship of the wing to the planing angle of the float bottoms to the water surface. Check the relationship of your keels to the decks of the floats. You may be able to use the decks for measuring purposes if these are parallel.

    You also need to set the relationship of the step to the loaded CG of the airplane. Determine where the vertical and horizontal loaded CG is located. This doesn't need to be precise, just reasonably close. Position the step of the floats 10 degrees aft of this point measured with the plane level. Again this is not precise since we know that the CG moves around in use. It is the starting point, which though testing has been determined to give the best water handling characteristics. The step position is determined by the length of the diagonal strut.

    You may (will) find it helpful to suspend the leveled naked fuselage above the floats for measuring purposes. You may also find it helpful to make a set of fittings out of wood for fitting purposes before machining the aluminum blocks. There are a lot of little angle differences in these fittings. The lefts and rights are mirror images. So that a little twist angle on one fitting will be opposite the one for the other side. The fittings which have two struts connecting may not have the same angles for each strut.

    Landing loads are distributed from the floats to the main landing gear point on the fuselage through a strut from the front of the float and another from the rear of the float joining at the main gear location on the fuselage. This is why you will notice that the diagonal strut angle is different between tricycle and tail wheel airplanes.

    I'm not familiar with the Patrol airplane. Where are you planning to attach your rear struts? That location on the fuselage must be able to transfer the landing loads from the rear strut into the fuselage structure. If you have a steel tube fuselage this should be a tubing cluster being able to spread the loads properly. If an aluminum structure this is also true with a different thought process in designing the reinforcements.
    More great information, very helpful.
    Looks like I need to find the book by Thurston.

    The rear attachments have been welded in and they are at a major cluster along the lower longeron. Bob Barrows is the designer/engineer of the Bearhawk Patrol, and his design was used for the rear attachments.

    It looks like the fittings are fixed, but until I get the plane hung up and the floats put together, I don't know if I will have any flexibility. The PA18 rigging I have is all brand spanking new, never mated to these floats or to an airplane. If only minor mods are required, I might be able to use the PA18 rigging I have, but if major mods are required I would probably better off to start from scratch when it comes to struts and fittings.

  10. #10
    TurboBeaver's Avatar
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    Quote Originally Posted by SuperDuper View Post
    Thanks TB

    The information you provided is exactly what I am looking for.
    Regarding the Patrol, it has lots of flaps and 180 HP, so I will start on the lower end of the scale with 2 degrees. I am thinking at this point, that it make most sense to just bolt up everything I have and see what I am starting with.
    The J3 on 1500 Aqua floats that I am flying has certainly illustrated the relationship between weight, density altitude, water conditions, and take off distance. In fact, I am going to double check the angle of incidence on that setup when I make the switch this year. Fortunately I have lots of water to work with here around the house. The Patrol will be making some real cross country trips, so T/O distance will be even more important.

    I appreciate the mission specific elements here, which brings another point to mind. How critical is CG placement relative to the step? Since the Super Cub and Patrol are similar in design, I am guessing (hoping actually) that there would not be a need to bring the floats forward or aft on the Patrol relative to the Super Cub. That would require modification to all of the struts. The Clamar resources the Cruzair mentioned above does have some information on the subject, but I would certainly welcome experience as well.

    Thanks Again,

    Clayton
    Clayton,
    Petes discribtion above like everything he posts, is spot on. I flew a Beaver once that had 5870 floats on it, they were designed for the " Bamboo Bomber" a fella in Renton Wa. (Clayton Scott)He had bought these as surplus and decided to sell them for Beavers! (Cheap $$$15K installed brand new!!!) Clayton Scott was an old bush pilot, but he was NOT an aeronautical engineer! He had cut a set of struts for them "he thought" should work fine. WRONG. He had the CG of the Beaver about 2' toooo far back! The results were this: The moment you added power, as it came over onto the step, you would run out of right rudder the plane would continue to circle left until you were airborne! So if you wanted to depart South you started East and then pasted thru N and W and finally T/O South! If you had a 10kt Xwind off the left side: it was compleately uncontrollable . We had to ground it. Clayton had to get Viking Air in BC to compute the correct lenght of struts for the 5870's. He then cut a whole new set. Flew up to Anchorage and installed them. He and I test flew it and BINGO, the boys in Canada had nailed it! It flew exactly the same as a factory Edo 4930 float! Alot of 135 guys used to mess with the rear struts on C-180 years ago and I think 4 degrees was where they ended up to get them to really perform heavy!
    Good luck.
    E

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    Last edited by TurboBeaver; 05-04-2019 at 07:35 AM.

  11. #11
    skywagon8a's Avatar
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    Don't be too quick to start from scratch. The installation on my Cub is using Citabria struts, some Citabria fittings and other fittings which I made myself. Feel free to ask questions. I've done so many of these that I do them in my sleep.

    Another thing, amphib floats pull the CG forward. Use the hydraulic power pack for CG control by placing it as far aft as is dictated by your weight and balance.

    The important thing to take from Thurston's book for your purpose is the step location and the "fish mouth" angle which I've described above. The rest is nice to know stuff.
    N1PA

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    FYI, I was NOT suggesting a negative angle. My point was that the relationship between the wing and float should be a positive. When Aviat approved the Baumann floats on the Husky, they started at zero angle of incidence, which worked fine on that airplane. FAA didn’t like zero, so Aviat changed to one degree positive.

    That resulted in arguably one one of the best performing seaplanes out there, and with no negative characteristics. Their intent was to achieve performance with good cruise performance. And they succeeded.

    The OPs plane sounds a lot like a Husky lots of power and big wing/flaps. He’s not talking 65 hp Cub here.

    Finally, you can cut some length off aft struts to increase the angle of the floats if you don’t care for the resultant performance of one degree, but I don’t see how you’re going to ADD to the length of those struts if you don’t like five degrees. Start with a small number in angle and shorten the aft struts if you’re not happy with performance.


    MTV
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    Bill Rusk's Avatar
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    Just as a reference point, I have a stock Supercub fuselage (factory dimensions) and stock Wipline 2100A floats, with factory rigging. A smart level on the top of the floats when zeroed out and then placed on the bottom of the wing gives 5.5 degrees. Seems to work well.

    Bill
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    Mike, This " Ie: floats are one degree up from angle of wing. Maybe two." is what gave me that impression.

    Rather than changing the strut length, make the fitting which joins the strut to the fuselage adjustable. Changing the strut length can not be done microscopically due to the edge distance requirements from the bolt hole to the end of the strut. The length would have to be changed by the diameter of the bolt hole plus the edge distance. This could be 3/4" or more when 1/8" is what is desired.

    Bill,
    What do you get for a cruise speed with 5.5 degrees? That sounds like there was a need for better take off performance so they sacrificed some cruise speed.
    N1PA

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    Bill Rusk's Avatar
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    I cruise at 100 mph at 2400 rpm with a 84/43 Catto prop, 180hp
    Off the water in 8 seconds, no wind, when light. Up to 20 seconds when loaded to 2300 pounds gross
    Bill
    Last edited by Bill Rusk; 05-04-2019 at 09:12 AM.
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    Quote Originally Posted by Olibuilt View Post
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    Folsoms sold a 95 Cub to a great friend of ours in the late 60's. They had stuck it on PK 1800s. It was an absolute dog...... He took it back to Dick and complained. They cut 3/4" off the rear strut ( that was a common amount they removed with 1400's on both PA11/18 struts) When he came home with it, it worked fine! No one had a digital level in those days but I will guess they had added a couple of degrees to the "fish mouth". Eddie Peck had a really good performing 90 Champ he told me he set it up with 6 degrees just for STOL performance but of course it was slow. Your Bearhawk with big flaps and 180 hp may as Mike suggests; simply perform so well with a couple of degrees you may not want to sacrifice
    a bunch of cruise just to get off a plane lenght quicker light? Petes Cub is similar to yours in HP and flap area,
    And the word off the "mukluk telegraph" is its almost a helicopter!

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

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    Plans are to do a preliminary fit up of the floats and fusealage starting Wed of this week. We have identified all but one set of the mounting blocks, and working on that. May be posting a picture for some help there. Bill has agreed to sends some pics of his Wip 2100A install, which will help confirm the use of the proper components and with dimensions.

    Pete: Really like the idea of making the rear attachment block adjustable. Cutting chunks out of the rear strut is limited to big steps (hole diameter and edge distance), and its really hard to put the pieces back together once your done with the saw. Could you post or PM a picture to me of one you have done in the past? This would help me get started with a concept drawing so that we could whittle a mock up out of piece of wood first.

    Mike: I am planning to start with 2 degrees, and adjust if necessary. I am sure the plane will jump out of the water, when compared to the floated J3 I have been flying.

    The one element I know that will need to be installed is the attachment of the water rudder pulley to the airframe. Looks like the Wip 2100's use the lower longeron as the attachment point via. a strap/clamp and a couple of eye-bolts. I have seen installations where the rear strut is used as the anchor point for that pulley, but with the cabling we already have, will most likely stick with the Wip way. May be cutting some fabric on this one.

    Thanks again for all the help so far. Will keep you posted on progress

    Clayton

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    Clayton

    there is a lot of info on float install here, you may have to scroll a little and filter but I think it might help.
    http://www.supercub.org/forum/showth...l=1#post637213

    Bill
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  20. #20
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    Clayton,
    PM your Email and I will send you pics of my rear strut fitting.
    Bear in mind that when the strut length is changed, the cross wire length is also changed. This may require making new wire pulls or adapters.

    I have seen pictures of using a piece of all thread between the upper end of the strut and the fuselage for testing purposes. I do not know the mechanics of how it was done.

    My fish mouth angle is 3.2 degrees measured between the top of the floats and a straight edge placed between the butt and first ribs on the bottom of the wing. Will send pic of this also. The top and keel of my floats are parallel.

    My rear float fitting is a block of aluminum 4" long. In my case it was used to lengthen the Citabria rear strut. The extra length of the fitting was to provide room to drill additional holes in case the fish mouth angle needed changing. It did not as I seem to have hit it right.

    My Cub is at least 5+% faster than Bill's. This could be the different prop and power setting in addition to possible aerodynamic differences. I normally use 22" mp and 2400 rpm. When I change the blade angle and push the throttle up it will do as much as 120 mph. If only I could change the blade angle in flight the performance increase at both ends of the range would increase tremendously. Time off the water is about the same as Bill.

    On my 185 I changed to a shorter rear strut and then to tweak that I added spacer washers under the float deck fitting. Originally I had to pull the yoke slightly to break water, now it will fly off on it's own.
    N1PA
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  21. #21
    SuperDuper's Avatar
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    Quote Originally Posted by Bill Rusk View Post
    Clayton

    there is a lot of info on float install here, you may have to scroll a little and filter but I think it might help.
    http://www.supercub.org/forum/showth...l=1#post637213

    Bill
    The post #1741 has exactly what I was looking for with regard to water rudder cables and routing.

    Thanks

  22. #22
    skywagon8a's Avatar
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    Quote Originally Posted by Olibuilt View Post
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    Quote Originally Posted by skywagon8a View Post
    You also need to set the relationship of the step to the loaded CG of the airplane. Determine where the vertical and horizontal loaded CG is located. This doesn't need to be precise, just reasonably close. Position the step of the floats 10 degrees aft of this point measured with the plane level. Again this is not precise since we know that the CG moves around in use. It is the starting point, which though testing has been determined to give the best water handling characteristics. The step position is determined by the length of the diagonal strut.
    For clarification purposes Oli's installation drawing is helpful.
    Assume that the vertical CG falls along the line labeled "flight line".
    Also assume that the horizontal CG is at a location forward of the intersection of the "flight line" and the "plumb bob" line.
    Draw a line from the horizontal CG location down to the point which is labeled "step".
    This is the 10 degree angle.
    N1PA

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    Quote Originally Posted by skywagon8a View Post
    For clarification purposes Oli's installation drawing is helpful.
    Assume that the vertical CG falls along the line labeled "flight line".
    Also assume that the horizontal CG is at a location forward of the intersection of the "flight line" and the "plumb bob" line.
    Draw a line from the horizontal CG location down to the point which is labeled "step".
    This is the 10 degree angle.
    Clayton,
    I have Edo 2000's on my PA12 the struts are factory Edo lenght for the original non flaped Cruiser. Edo struts are 4 degrees. That will net us 95mph
    at 2400 and 100mph at 2500 with a flat prop.
    Just for reference!Click image for larger version. 

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  24. #24
    skywagon8a's Avatar
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    Quote Originally Posted by skywagon8a View Post
    My fish mouth angle is 3.2 degrees measured between the top of the floats and a straight edge placed between the butt and first ribs on the bottom of the wing. Will send pic of this also. The top and keel of my floats are parallel.
    This has me thinking of an old thread. http://www.supercub.org/forum/showth...sa+35b+airfoil
    Using that thread's information would place the angle of incidence of the floats on my Cub to the chord line 3.2 + 1.54 = 4.74 degrees.
    NOTE: Do not confuse the angle of incidence which is measured from the chord line to a measurement along the bottom of the rib.

    These numbers would make Bill's floats be at 5.5+1.54=7.04 degrees. That seems excessive to me. If he can adjust this angle easily he would find a bit better performance.
    N1PA

  25. #25
    Bill Rusk's Avatar
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    Pete

    Yeah, I have considered that but that is factory rigging so I guess it should be the same for all Wip/SC combinations.?
    My Cub flies great so I have been reluctant to experiment. Maybe someday just for fun....

    Because of the angle you can't land fast. Above 60 it gets pretty uncomfortable as you are landing on the front of the floats and you get a pretty good pitching movement and it slows uncomfortably. Sweet spot seems to be around 50. Below 45 I start to get the heels of the floats a little. Below 40 is on the heels.

    Bill
    Very Blessed.

  26. #26
    skywagon8a's Avatar
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    Bill,
    Is the plane level in this picture? If so, taking into consideration the parallax from the camera location notice how low the bows are. That is your difference in cruise speed when compared to mine. My landing speeds are below 40 without dragging heels.

    Click image for larger version. 

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    N1PA
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  27. #27
    SuperDuper's Avatar
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    Got started today with setting up the Wip 2100's to the Patrol and looking for an end of day sanity check. Wish I could say we made more progress, but we did get the plane up off the ground, the landing gear off, and the spreader bars installed. Didn't drop anything or cause any injuries resulting in significant blood loss.

    At this point, and based on my experience with the Aqua 1500's, I am really wondering if I have the right spreader bars. The outside dimensions of the 2100's with the spreader bars install is 9'6" at the widest point. That is a full 12" wider than what the Aqua 1500's measure. Keeping in mind, the Aqua 1500's are STC'd for the PA18's with 90 or 105 HP. The width of the spreader bars I have for the 2100's is 69 1/2".

    Bill Rusk is away from his plane at the moment, so he can't measure his for me. Was hoping someone who is following the thread might be able to help out with a measurement or two, even if it is for a different set of floats than the Wips.

  28. #28
    mvivion's Avatar
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    Quote Originally Posted by SuperDuper View Post
    Got started today with setting up the Wip 2100's to the Patrol and looking for an end of day sanity check. Wish I could say we made more progress, but we did get the plane up off the ground, the landing gear off, and the spreader bars installed. Didn't drop anything or cause any injuries resulting in significant blood loss.

    At this point, and based on my experience with the Aqua 1500's, I am really wondering if I have the right spreader bars. The outside dimensions of the 2100's with the spreader bars install is 9'6" at the widest point. That is a full 12" wider than what the Aqua 1500's measure. Keeping in mind, the Aqua 1500's are STC'd for the PA18's with 90 or 105 HP. The width of the spreader bars I have for the 2100's is 69 1/2".

    Bill Rusk is away from his plane at the moment, so he can't measure his for me. Was hoping someone who is following the thread might be able to help out with a measurement or two, even if it is for a different set of floats than the Wips.
    Nine six sounds about right to me. They aren’t legal width to trailer on the road.......1500s are itty bitty floats compared to those Wips.

    MTV
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  29. #29
    skywagon8a's Avatar
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    EDO 2000s are 85" center line to center line (keel to keel). This is the same no matter what airplane they are installed on. The lower strut fittings attach to the floats with a "hinge" bolt arrangement which allows for differing fuselage widths.
    N1PA

  30. #30
    SuperDuper's Avatar
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    Quote Originally Posted by skywagon8a View Post
    EDO 2000s are 85" center line to center line (keel to keel). This is the same no matter what airplane they are installed on. The lower strut fittings attach to the floats with a "hinge" bolt arrangement which allows for differing fuselage widths.
    Mike / Pete - thanks again for the help. This all checks out with what I have with the Wips. Bill had also provided me with some information on Aerocets that he came up with, which indicates an 86" keel to keel measurement. The Wips are 86".

    Looks like I will be back at it again today.

  31. #31
    skywagon8a's Avatar
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    Clayton,
    Since the advertised cruise speed of the Patrol is significantly higher than a PA-18 I strongly suggest that you lean towards a smaller fish mouth angle than that which is designed into the installation by Wipline. Bill's Cub is 5 mph slower than mine which I attribute to the 2-1/4 degree difference in the fish mouth angle. The aerodynamics of the floats is also a contributor. When your land plane cruise speed is considerably higher as yours is supposed to be, that wide angle will produce a much larger drag component. In those cruise speed ranges it is not uncommon to see a 15+ mph speed penalty. So less is better. Your long flaps coupled with the 180 hp will make up for a smaller fish mouth angle for your take off performance.
    N1PA

  32. #32
    SuperDuper's Avatar
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    Had another productive day with the floats today - really appreciate all the dimensions and help provided through the forum.

    We did get far enough along to move forward now with fabricating a mount for the water rudder cables, balance line, and routing for the retract cable. The fuselage will be getting paint once the new mount is in place.

    Pete - Looks like 3 degrees of fish mouth will be the right number to start out with to me.

    Regarding the struts, and considering the structural design of the Patrol, what are the thoughts about using the forward gear attachment for the forward float strut, and aft gear attachment for the diagonal float strut (where the SC uses the front attachment for both). The downside would be the possibility of a Z type force along the longeron between the two points, but the upside would seem to be a far greater distribution of load across multiple structural members. The other advantage of using the forward gear fitting for the forward float strut is the fact that the strut would be more in the vertical - which I am thinking would result in less force being transfer to the aft attachment at the longeron in the event of a hard landing.

    One more question for those with experience with ventral fins - do you think the Patrol might need one?
    Last edited by SuperDuper; 05-09-2019 at 06:31 PM. Reason: question about ventral fin

  33. #33
    mvivion's Avatar
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    The Husky benefits from a fin, and frankly the super cub could use one too. That said, as long as you’re not lazy with the foot work, it may be just fine.

    Rather than a fun I’d use “Finlets” like a lot of American Champion planes use. They don’t stick down as far.

    MTV
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  34. #34
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    Click image for larger version. 

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ID:	42854 Yes you can use the front gear fitting for the front strut and the rear gear fitting for the diagonal strut. If there is a question of strength you could tie the two together with an external tie of sorts.

    Look up a picture of a Beaver on floats. It will show the struts utilizing separate attachment locations. That aft strut is for a step to the cabin door not a float strut.

    The Citabria with Oleo landing gear uses a tie rod between the front and rear gear fittings to absorb eccentric loads.

    The following may be informative or may be just too much overload:
    https://apps.dtic.mil/dtic/tr/fulltext/u2/645667.pdf
    https://booksite.elsevier.com/978012..._SEAPLANES.pdf

    A ventral fin requirement will be determined during flight testing. Some need one, some do not and others don't but do fly better with. The tail wheel spring support will serve as a primary connection point. Or you could place one on each stabilizer. As you can see my Cub has one. Without it there was an excessive amount of fishtailing. It was very tiring to fly it. Now it is a pleasure to fly. That fin came from a Husky. It was available so I used it and made no effort to fine tune its dimensions. I have flown the 7GCB without tail fins. You could step on the rudder skidding the fuselage sideways and it would stay there. With the fins it would fly straight.

    Upon further thought since it is expected that your plane will have a relatively high cruise speed, it is very likely that additional fin area at the tail will be desired. The directional stability of a float plane becomes more sensitive the faster it goes. This is because the air loads against the side of the forward section of the floats will be opposing that of the tail.
    Last edited by skywagon8a; 05-09-2019 at 07:41 PM.
    N1PA
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  35. #35
    BC12D-4-85's Avatar
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    These may already be noted above. All I have bookmarked and know about this float rigging business. That is besides loading the plane to gross at both forward and aft CG then go fly.

    http://www.stoneylake.org/pipcom/floatgeo.htm
    http://www.supercub.org/forum/showth...Rigging-floats Note Post#11 from JJ Frey

    Gary
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  36. #36
    TurboBeaver's Avatar
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    Quote Originally Posted by skywagon8a View Post
    Click image for larger version. 

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ID:	42854 Yes you can use the front gear fitting for the front strut and the rear gear fitting for the diagonal strut. If there is a question of strength you could tie the two together with an external tie of sorts.

    Look up a picture of a Beaver on floats. It will show the struts utilizing separate attachment locations. That aft strut is for a step to the cabin door not a float strut.

    The Citabria with Oleo landing gear uses a tie rod between the front and rear gear fittings to absorb eccentric loads.

    The following may be informative or may be just too much overload:
    https://apps.dtic.mil/dtic/tr/fulltext/u2/645667.pdf
    https://booksite.elsevier.com/978012..._SEAPLANES.pdf

    A ventral fin requirement will be determined during flight testing. Some need one, some do not and others don't but do fly better with. The tail wheel spring support will serve as a primary connection point. Or you could place one on each stabilizer. As you can see my Cub has one. Without it there was an excessive amount of fishtailing. It was very tiring to fly it. Now it is a pleasure to fly. That fin came from a Husky. It was available so I used it and made no effort to fine tune its dimensions. I have flown the 7GCB without tail fins. You could step on the rudder skidding the fuselage sideways and it would stay there. With the fins it would fly straight.

    Upon further thought since it is expected that your plane will have a relatively high cruise speed, it is very likely that additional fin area at the tail will be desired. The directional stability of a float plane becomes more sensitive the faster it goes. This is because the air loads against the side of the forward section of the floats will be opposing that of the tail.
    Pete,
    Interestingly enough the fins on the horizontal stabilizer came in different
    configurations: on Champs/Citabrias.
    Some required only a fin on top, but other models required BOTH top and bottom. As a side note, having fins on your stabilizers when your floats are removed has an adverse effect on the ability to slip the airplane. Not a big issue if your flaped, but my old GC(flapless) that slipped nicely without fins, sure was limited with fins!

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

  37. #37
    skywagon8a's Avatar
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    Quote Originally Posted by TurboBeaver View Post
    Pete,
    Interestingly enough the fins on the horizontal stabilizer came in different
    configurations: on Champs/Citabrias.
    Some required only a fin on top, but other models required BOTH top and bottom. Some also had a fuselage ventral fin. As a side note, having fins on your stabilizers when your floats are removed has an adverse effect on the ability to slip the airplane. Not a big issue if your flapped, but my old GC (flap less) that slipped nicely without fins, sure was limited with fins!
    That depends on whether the Champ had the big dorsal or not as well as which set of floats were under it. The smaller floats 1320s & 1400s only needed the fins on top of the stabilizers because the area of the floats which was forward of the CG was smaller. When the floats had more area forward (2000s) they had to increase the fin area. The earlier ones were rounded on top while the later ones were swept back squared to match the Citabria tail shape.

    The slipping issue was because the area of the floats forward of the CG was removed, so that now the fixed vertical had too much area for the rudder to over power,

    If you wanted to take the time doing some measuring and math, you could calculate the size of the extra fin requirement for whichever floats you were using. It would involve a side view of the airplane with and without the floats. The loaded CG location marked on the fuselage. Divide the fuselage and floats into segments. Calculate the area of each segment along with it's center location. Using each segment's area and center set them up as though you were doing a weight and balance calculation. Area X Arm = Area moment. The result instead of being weight and CG would be an aerodynamic center of force. Once you know this you can add tail area until the center of force matches your center of gravity. I've never done this however it would be a fun rainy day project.
    N1PA
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  38. #38
    BC12D-4-85's Avatar
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    M R Borer's SA289AL STC for the PA-12/14 adds external rudder centering springs when on floats. A cable's run forward from each lower rudder horn to the side lift handles and a common rudder spring incorporated on each cable. I had that on my PA-12 and it worked ok with EDO 2000 floats. Never tried a fin so don't know if that's better.

    Gary
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  39. #39
    skywagon8a's Avatar
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    Quote Originally Posted by BC12D-4-85 View Post
    M R Borer's SA289AL STC for the PA-12/14 adds external rudder centering springs when on floats. A cable's run forward from each lower rudder horn to the side lift handles and a common rudder spring incorporated on each cable. I had that on my PA-12 and it worked ok with EDO 2000 floats. Never tried a fin so don't know if that's better.

    Gary
    Gary, That is the BS method of passing the FAA flight test requirements for certification. This method has been used for many float approvals. However it doesn't really correct the reason for the instability. The test involves trimming the airplane to 1.3 Vs. Then while holding wings level with ailerons immobilized, the rudder is displaced generating a large yaw in excess of 10 degrees. Release the rudder pressure and the nose is allowed to swing past the original heading stabilizing not more than 10 degrees off the original heading. Friction and aerodynamic loads on the rudder sometimes inhibit the return. Then the fix is to add the springs to pull the rudder to the neutral position OR add more vertical tail area. My memory may be off in the exact numbers, but that is the general idea of how the test is done.

    Having said that, the FAA is happy and the certificate is issued. However when the pilot is flying on a hot turbulent summer day on a long trip to his favorite fishing hole the tail will be wagging and the wings will be rolling. The pilot will be working the ailerons and rudder attempting to tame the ride. As a result the pilot will be all worn out in short order. The float manufacturer doesn't care since he got his certificate and sold his floats. Now to make the pilot happy and ready to catch the big fish fully rested when he arrives, put some more fin area at the tail. I know there are those that don't want the extra tail interfering with ground handling or taxing crosswind. ME, I'll take the increased tail area, you can have the springs.

    P.S. Piper certified the PA-12 with the extra fin. Over time many fins were lost and thus left off. Eventually everyone forgot that they were supposed to be there. That is likely why Borer acquired the STC, to correct a defect which shouldn't have been there.

    P.S.S. I installed the first set of EDO 2440 floats on a 172 XP in New England. The floats came with a set of rudder centering springs which attached to the outside of the fuselage at the tail. I was told by certain people who will remain nameless, that the best thing to do was to accidentally drop the springs deep in the water.
    Last edited by skywagon8a; 05-12-2019 at 01:16 PM.
    N1PA

  40. #40
    BC12D-4-85's Avatar
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    Hah good laugh here Pete and thanks. I'd heard that before so must be true. That 12 had an enlarged rudder and fillet in front of the vertical stabilizer so probably wasn't as bad (SA570AL). Today I'd add rudder and elevator gap seals to further enhance those controls. There's also SA5-54 (one time approval) for sea fins. I'd rather have something like that (via Citabria's bolt on or Beaver's stabilizer end plate designs) than that goofy ventral fin getting in the way. I guess I noted some increased leg action in flight but that gave me some exercise and things to do while tying flies enroute to the fish hole.

    Actually in the air I just dropped the water rudders and that seemed to help some.

    Gary

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