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Building A 82 Inch Protege Float Plane
 
Author: Bill Cousins

Iv'e decided to build another float plane, and set my sights on a Carl Goldberg Protege. I do have three other float planes and this just adds to my collection. I do enjoy flying off the water on a nice calm day or evening. As I got started, the decision was made that I wanted to extend the wing span, so I decided on 82 inch. {The original wing span is 70 inches } The plans were drawn up and I got started. I first built the rudder and fin assy. and then built the stabilizer and elevator, these I kept to the plan. Next I started to build the wing { I bought another wing kit for the plane } I needed extra leading edge and trailing edge and also more ribs {I could have cut them myself, lazey??. The wing went together very good, and extended the wing three quarters the way out, that way there is less stress on the whole wing. Where I extended the wing I reniforced it with plywood strips, also sheer webed both sides of the main spar. There will be four servos in the wing, 2 aileron- 2 flaps. The wing ends are going to be flat with end plates installed instead of curved up. Why?? I don't know I think it will be more stable. When I joined the wings together I made two extra deheidral braces because of the wing span. I was going to make the wings straight, but reluctantly gave the wing one quarter of an inch deheidral, I guess for a little lift. Also sheeted most everything except a bit in the middle, this wing won't go anywhere. The ailerons are cut back a bit to give me more flap area. The fuselarge is just banded together right now, as that is as far as I have got with it for now. I will be using Slocan 42 inch wide floats with two water rudders and one mini servo to operate both rudders. I have now glued the fuse. and epozied the fire wall in with triangle bracing { EPOXIED }{ don't forget to glue triangle bracing } Fig.#1. { Don't forget to do this to ARF's, this is very important as their glue is not trust worthy. } Also installed the plate in the front for the gear and floats. Fig.#2 Epoxied the ply plate just behind second former for the back float assembly.. Fig.#3 Also installed the servo tray Fig.#4 Well I finally finished the fuse installed the Satio .91 4-stroke, installed all the servos, battery, and reciever. The tail feathers are installed and is finally all covered in ultracoat {cream} with {smoke}
purple covering underneath. A Dubro landing gear with 4" Dubro wheels and a Sullivan tail wheel. I will test fly this plane on a grass runway and trim it out, then take the wheels off and replace them with the floats. Now to cover the wing. Finally the wing is all covered, the servos are in and the wiring is done, but still have to put all the control horns on and all the linkages in yet. The hinges have to be epoxed in and the winglets have to be made yet. Also the float rigging and the floats have to be assembled. Well the plane is finally done and flying. The first time up was good with no surprises, just a few clicks on the elevator and aileron and it was flying straight and true. Now that it is flying and trimmed, the next step is setting up the floats.

It basically took a whole day to set up the floats and these floats are 42 inch Slocan floats, foam core and fibreglass on the outside. Using Dubro fibreglass landing gear as well as home made angle brackets made by a fellow modeller from our club, these are screwed in using three Allen screws per bracket. I also installed a small piece of plastic sheeting underneath the motor so the spray of the water doesn't get sucked up into the carb (remember down draft carb on 4-stroke }. Even on a 2-stroke you may want to do this, just depends on how the motor is installed. I also installed two spreader rods for support for the floats. Always remember to reinforce the fuselage where the landing gear is bolted before using floats.

Next came two Ernest water rudders (why two?) because in a breeze one water rudder may not be enough to turn your plane. You can use any type of water rudders and you can even build them yourself but I prefer these. Also installed the proper linkage and micro servo attached to the landing gear. You will need a Y harness connected to the rudder through the receiver and this attaches to the micro servo or any type of servo, but a micro servo is more compact and all it is doing is moving two small rudders in the water. This set-up I find more responsive than running a cable. The water will not get into the micro servo if you are careful and always remember to attach a small diameter cable from the motor to the floats or landing gear so if it goes in hard you won't lose your motor. ALWAYS REMEMBER that the STEP of the floats HAS to be under the CG of the plane, this is very important. And the tips of the floats should be 1-2 inches past the propeller. One more thing that has to be done is place your reciever and battery in a water tight plastic bag individually and make sure it's SEALED. Also take along a small boat or rubber dingy just in case it quits out there or { heaven for bid } it goes in. Sometimes I add small "splash guards" on the bottom of the floats from the tips back about a foot, this prevents alot of water spray when reaching air speed to get on the "step". Some floats also come with it. I am using a Hitec Optic-6 radio, it is a very good inexpensive unit and have programmed in flaps and also crow along with a little rudder along with the ailerons. This unit is a 10 model memory which is very handy when flying more than one plane.

Being that I built this plane a little heavier than the original plans called for, and also addsd twelve more inches of wing I had to install a fair bit of weight on the floats to balance it properly, I wasn't sure if it was going to get off the water easily. The first flight off the water was graceful and the 91 Saito picked it up with ease.

Alwsys remember when you install your floats, make sure you re-balance your plane, this is " very important " and if you have to add any weight add it to the floats, this way when you take your floats off and install the wheels your plane is still " In Balance"
Wing incidence also has to be checked when float flying, and if not correct you may not get off the water. The wing to float angle has to be greater at the leading edge than from the trailing edge. This means there should be 2-3 degrees more at the leading edge than the trailing edge. Roughly about one half an inch. Now there are different variations on floats and if you need more info there is alot on the web by just searching FLOAT FLYING. Also the float spread should be about 25% of your wing span.
 

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Another Picture Of It
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Another Picture Of It
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Another Picture of the Fuse
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Epoxied plate just behind second former for the back float assy. Fig.#3
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Epoxied the fire wall and also triangle bracing Fig.#1
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Fire Wall & Motor Mount With .91 Satio 4-Stroke
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Float set-up
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Flting on Edith Lake #1
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Flying on Edith Lake #2
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Flying on Edith Lake #3
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Fuselarge Banded Together But Not Glued Yet.
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Installed plate in front of the first former for the gear and floats Fig.#2
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Installed servo tray Fig.4
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Micro servo for water rudders
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Plastic Splash Guard
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Protege .91Satio 4-Stroke
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Protege 82 Inch Wing
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Protege 82 Inch Wing #2
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Protege beginnind to look like a Plane
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Protege Fin & Rudder Assembly
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Protege Fuse Done
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Protege Rudder
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Protege Stabilizer
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Protege Stabilzer With Elevator
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Protege Wing Ass. 80% Done 82 Inch Span
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Protege Wing Flaps Will Be Installed
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Rudder set-up
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Safety Cable from motor to the floats
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Servo wire set-up
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Slocan Floats Will Be Installed 42 Inch With Two Water Rudders
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Tail feathers installed on Protege

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