I would avoid any trailing edge additions. Those would only serve to negate most of the advantages of the leading edge cuff. If you look at it like an airplane wing, the leading edge cuffs add surface area to generate more lift. On some "Bush Planes" That cuff droops ever so slightly in order to generate more lift at slow air speeds. Such as those during take off and landing. The leading edge devices on airliners do the same thing, but are movable. Anything on the trailing edge also increases lift and drag for those same regions of flight, however they generally increase the aircraft pitching moment quite a bit. We also use little aluminum trailing edge tabs to "trim" the aircraft as well. Most small aircraft they are fixed, they are movable on larger aircraft. Most small aircraft has movable trim in pitch attitude. Fixed in roll and yaw. All that having been said, a trailing edge tab would do nothing until the tiller is deflected, at which time it would increase the forces required to move the rudder. So counter productive. As far as attaching it, you really don't need to screw it down, just a little water proof tape would hold it in position perfectly. We used to flight test winglets on the tips of high performance racing gliders that were just molded over the existing tip, then taped into place with 3M electrical tape. They would be good at airspeeds in excess of 160 MPH and G loads over 4 G's. My plan was to mold it snug, add some type of substance like petroleum jelly to give it some surface tension and tape the edges up to keep it from shifting around. If it worked, then I would probably just use a little 4200 to stick it down and call it good. My other thought was to recreate the kick up portion in glass covered wood so I could swap them out as desired without ruining the class legal rudder.
Rudder wanted or dimensions
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Neal, I'm going to be real interested in the trials, and tests of this addition. And permanent construction. Keep photos man..
Rog that. I was hoping to paint today...but this little annoying thing called Sandy is keeping me at home! I have to go up there tomorrow to run an errand, I might grab some glass and play around a bit. I'll post photos.
030 @25kts gusts to 40 or so, probably will go a bit higher before it is all said and done. Seas are about 15 feet, and just downright ugly. Glad my boat is not in the water! Not too much in the way of rain, just the occasional squall.
I am on the sixth floor here on Cocoa Beach, and I saw some IDIOTS on the beach next door at the hotel with 3 little kids trying to go SWIMMING! Unreal... I called 911 and they had beach patrol come have a little "Chat" with the "adults".
I am on the sixth floor here on Cocoa Beach, and I saw some IDIOTS on the beach next door at the hotel with 3 little kids trying to go SWIMMING! Unreal... I called 911 and they had beach patrol come have a little "Chat" with the "adults".
Oh good God. The world is full of 'em man.
Tomorrow, they're saying 24, to 32 ft. seas here. And the Stede Bonnet regatta tomorrow as well. I would LOVE to sail a 32' Beneteau in that mess.
Well, maybe not..
It would be like the tourist on the beach mentality.
They wanted us to dress as pirates anyway.
Maybe a Somalia pirate I'm thinkin'..
Tomorrow, they're saying 24, to 32 ft. seas here. And the Stede Bonnet regatta tomorrow as well. I would LOVE to sail a 32' Beneteau in that mess.
Well, maybe not..
It would be like the tourist on the beach mentality.
They wanted us to dress as pirates anyway.
Maybe a Somalia pirate I'm thinkin'..
Hi, I completely understand what you've written about wing controls...flaps (leading and trailing.) My comment is that we aren't quite dealing with the same thing as a typical aircraft wing because the rudder needs to be symmetrical in chord and camber for both port and starboard applications. So, if it resembles any sort of wing, it wold be that of a stunt plane which allows the craft to fly reasonably level while inverted. In this case what I was referring to was to lengthen the chord slightly as this may decrease rudder side-slip without interfering with the design in a way that still allows the boat some weather helm and to round up. At any rate, I do agree that it somewhat negates the easier steering effect that you are going after but it wouldn't act as drag if both leading and trailing edges were added.
I think that in a like way, the basic flaw of the swing keel is the somewhat increased leeway from it's shortened chord, even if part of the reason why the keel isn't lowered to vertical is because the angled keel adds more length to that chord.
I think if you were to add an equal percentage on the leading edge and trailing edge of the rudder, you would just make it more effective. And proportionally more difficult to move. My desire to reduce the control forces required to deflect the rudder blade by adding a leading edge extension moves the center of lift of the airfoil closer to the pivot point, reducing the required forces to deflect the foil.
Keep in mind, that any deflection of an airfoil creates the desired lift, and with it the undesired drag. As any function of lift is generated, the drag produced and forces required to deflect goes up by the square. So for a 5% increase in overall area, you will get a 25% increase in drag or forces required to move it. It would reduce the side slip angles of the rudder, but the overall added loads would quickly surpass what the attach points could handle. As it was, I tried to gently steer the boat the very first time I launched it without the rudder locked down, it broke the top pin. I had to grind away the very poor quality casting and add a strap style pin with through bolts.
A more effective method would be to reduce overall chord and increase the aspect ratio producing a more effective surface with lower drag. That would be a skinnier longer blade. Think glider wing versus Cub wing. That is what IdaSailor did with their rudder.
I personally hate how much weather helm the Catalina 22 has. And I hate how much control force the tiller needs. My goal was to reduce, not eliminate the amount of both in order to make it more tolerable.
I am planning on selling the boat for 2 reasons. #1 The swing keel. HATE IT. #2 Weather helm and tiller pressure.
I just rebuilt the keel, and will attempt to fix the rudder issues. I want a Catalina 27 with wheel steering for this main reason.
Keep in mind, that any deflection of an airfoil creates the desired lift, and with it the undesired drag. As any function of lift is generated, the drag produced and forces required to deflect goes up by the square. So for a 5% increase in overall area, you will get a 25% increase in drag or forces required to move it. It would reduce the side slip angles of the rudder, but the overall added loads would quickly surpass what the attach points could handle. As it was, I tried to gently steer the boat the very first time I launched it without the rudder locked down, it broke the top pin. I had to grind away the very poor quality casting and add a strap style pin with through bolts.
A more effective method would be to reduce overall chord and increase the aspect ratio producing a more effective surface with lower drag. That would be a skinnier longer blade. Think glider wing versus Cub wing. That is what IdaSailor did with their rudder.
I personally hate how much weather helm the Catalina 22 has. And I hate how much control force the tiller needs. My goal was to reduce, not eliminate the amount of both in order to make it more tolerable.
I am planning on selling the boat for 2 reasons. #1 The swing keel. HATE IT. #2 Weather helm and tiller pressure.
I just rebuilt the keel, and will attempt to fix the rudder issues. I want a Catalina 27 with wheel steering for this main reason.
Yes. That was my only point.
It is a good motivation to make this change.
Ouch. I noticed that backing with the rudder in the up position is a bad recipe. The force on the rudder/tiller to turn becomes significant.... So, by sheer luck while learning I've not broken something on the rudder or chewed it up on the prop I have learned to watch out for that.
I have not seen the fairing of the IdaSailor blade. Construction materials and strength may come into play. I'm surprised that the C22 kickup is actually as thick as it is and that some have failed. I measured mine at about 1 1/2" maximum thickness. Is not much of this aero/hydrodynamic (dependent upon speed as well? As an example the old Ford Trimotor wing had great lift but limited the craft to a slow airspeed.
I can relate to this. Part of the problem may also be caused by hull shape /length. She's wider than some boats in the same length. Center of force vs. keel>Rudder distance. We can't change those things without some drastic work. Have you experimented with your mast rake?
My issue with the C22 swing keel is that it cold be attached more solidly. It boggles my mind that they use basically the same hardware with the heavier keel on the C25.
The 27 would also give one more interior comfort. We must remember that the 22 seems more like a trailer sailor / pop up camper of a design. I think that they insinuate that you can sleep 5 inside. Interior space down below is limited for one person and becomes crampt beyond two. With two adults and three kids, there would be more space in the trunk of a '76 Pontiac Catalina.
For our purposes, towing weight, lake size, day sailing in light-moderate conditions we enjoy our 22 a great deal. It seems that this boat is designed to be a tad more forgiving for a novice and as beginners at the time my wife and I were mostly lucky to have chosen the design and to have found ours in reasonably decent condition.
I have also seriously considered either making a rudder design with more of this the forward area for ease of steering, buying the Idasailor or altering my kickup.I think that altering is the easiest but I don't want to mess up what I've got. Someday, I will need another gallon of West System and making one may be an interesting project.
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