It really is experimental aviation.

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mikegtzg
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Joined: Tue Mar 23, 2004 12:05 am
Location: 1000' & 66 kts. above Manitoba

It really is experimental aviation.

#1 Post by mikegtzg » Fri Nov 18, 2005 9:17 pm

The prospect of flying a floatplane has intrigued me for years. Last year I flew to the Red Lake ‘Norseman Festival’ on wheels. It was fun and an adventure but felt like a second class attendee. If only I could fly there on floats. Then I could stop shaving, and rub fish on my clothes and be a real bush pilot. In my daily ritual of scouring the internet for bargains in the aviation world I chanced upon a set of Full Lotus inflatable floats, new and still in the box at a very reasonable price. The Norseman Festival was 32 days away. Could I do it?

Ten days later I have a box of tubes, floats, and a manual that says check with your manufacture for mounting details. I have two homebuilt airplanes. A low wing and a high wing. Neither model has ever been floated before. Since the floats are yellow
I choose the yellow high wing. There isn’t much rigging info for aircraft on floats other than model specific certified by the manufacturer. Research on float CG, step location, optimum aircraft CG, and float incidence angles are talked about in ranges. Where do I start?

I decide to take holidays from work and a week later the install is almost complete. On a homebuilt aircraft converting to floats is considered a major change and requires a new C of A and an inspection by Transport. As well, a flight restriction of 25 nm and 25 flight hours applies. A stack of papers and a cheque later, Transport inspectors sign off on the project. Its now, about 10 days to the Norseman Festival. The aircraft is put back on wheels, flown to Lac Du Bonnet, and returned back to floats. Lac Du Bonnet is a sleepy but unique airport. The land runway and water aerodrome are 100 yds. apart. There was a lot more itinerant air traffic than usual though. Word of the unique project spread and there were groups pilots standing around like city workers watching the goings on.

I first water taxi around and gradually add power. The yellow side is staying up, this is good. The aircraft wallows around nose up plowing lots of water and certainly nowhere near flying. The Sensenich prop used on wheels always performed adequately, but in the water it was a dog. Without the benefit of acceleration the prop would not give me the rpm needed. So after 2 days of trying I decide to change the prop. 5 days to the Norseman Festival.

Warp Drive make ground adjustable carbon fiber props for the experimental market. I rush in a 2 blade model (a must for hand propping) and install it. The engine now pulls 2430 rpm static. An increase of 400 rpm from the wood club removed. The plane is placed back in the water and more attempts. The acceleration changed remarkably, but I have to hold full forward stick to not drag the heels of the floats. I’m thinking now of using a glider tow hook and getting some help from the Otter at the float base.

When the floats were set up they were rigged with 3.5 deg. down incidence from the fuselage. The wing chord is rigged 2 deg. up for a total of 5.5 deg. After close inspection of the Cessna 180 parked next to me I decide to increase it. This will bring the heels of the floats up and give the wing more angle of attack on take off. The rear float struts were shortened to 6.5 deg for a total of 8.5 deg., and all the control cables for the water rudder had to be shortened. This is tough work in 30C weather. The neighbour with the 90HP Champ on floats brought over a cooler of cold drinks.

Time to put it in the water. This time it gets on the step with neutral stick. Backtracking on the lake is time consuming. At 800 rpm it can be 10-15 minutes to get to the right spot to start the take off. I apply full throttle, and start the take off run. It gets up on the step, and its still accelerating. I look over at the right float and water is still spraying off, then the left. The left float is out of the water, now the right is. Holy #$%@ it’s flying. I did a climb and a large circuit taking about 20 minutes and feeling the changes the floats have made too pitch sensitivity and roll. It actually flew well. With a reduced climb but much more stable than on wheels or skis. The time of first flight was concurrent with the formation flypast the big old Norseman Floatplanes do signifying the end of the festival for another year. I almost made it.

Perhaps the floatplane gods were in my favour that day. After the flight I parked the plane for a return the following weekend. And it never flew again. I tried to get it off the water for 3 hours of take off attempts, and doing every imaginable combination of stick work. Maybe the wind was stronger that day, or I bounced off a big wave or wake. The successive take off attempts were on cooler days with moderate winds. The floats were removed and the plane brought home on wheels again.

There is a bright side. The performance of the aircraft with the new propeller on wheels is incredible. If someone had told me that the improvement in take off and climb performance was that dramatic I never would have believed them. Further research on floatplanes gives me another idea. The aircraft on floats was always at the rear end of the Cg envelope. Most floatplanes are ideally loaded to the forward Cg envelope. Since there are no controls in the front seat I could not try this. But there is 11 months to the next Norseman Festival.
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