Wide Body Float Fittings.

[rv6ator]

For those of you that have mounted floats on a wide Body Super Cub (Javron), will standard PA-18 float fittings work?

 

[ak49flyer]

Yes everything should work but you’ll probably need longer wire pulls for the flying wires; easy enough to make.

 

[skywagon8a]

Spring Lake? Looks like a nice spot for a float plane.

 

[rv6ator]

I would assume the aircraft would sit slightly lower on the floats.

 

[skywagon8a]

I would assume the aircraft would sit slightly lower on the floats.

If anything, slightly higher because the struts would be slightly more vertical. Most likely a fraction of a fraction of an inch. As ak49flyer says, longer wire pulls.

 

[chrisinak]

If anything, slightly higher because the struts would be slightly more vertical. Most likely a fraction of a fraction of an inch. As ak49flyer says, longer wire pulls.

Is the same true for PA-12 fueselage? Can you use PA-18 rigging or are there more substantial changes needed?

 

[BC12D-4-85]

I used PA-18 rigging on a PA-12 for four years. A&P installed and test flew. We were pleased.

Gary

 

[scaleram]

Did you happen to measure the throat angle? The wing incidence is 3 degrees less on a PA-12, than an 18.

 

[BC12D-4-85]

Did you happen to measure the throat angle? The wing incidence is 3 degrees less on a PA-12, than an 18.

Not exactly. I flew it for 4 years on floats - EDO 2K's with PA-18 rigging. The rigging was the early style with riveted ears for attachment vs machined ends. The ears can be "adjusted" in or out 3/4" at a time per end. After 3 years I shortened the rear upper ends 3/4" as an experiment and ended up with 4.5* throat angle. So, I assume it was 3-4* prior but don't have notes in my logs from that early time. No great improvement noted on takeoff but slowed a few in cruise. So I reset it to standard length rears. Either way it was a performer with O-360, long prop, 60 fuel, extended wings, Crosswinds cuff then removed and VG's installed (better with VG's and gained 8-10 mph in cruise w/o cuff). Always off at GW within 500' on floats. Cross tie wires took lengthening tabs to fit. All my logs say.

Edit: FWIW that PA-12 had PA-18 gear and fuselage fittings so maybe that's another consideration that might affect the fit (?).

Gary

 

[BC12D-4-85]

One more thought re PA-18 rigging>PA-12. Find a set of both and measure strut length for all three per side. I did that once and they were slightly different. Don't recall how much tho. The 12 fuselage I assume is wider so that makes the strut angles different (more vertical?). More vertical means fuselage further from floats? Not sure how that changes things front and rear but I never had an issue with aft or forward CG loading and floatation or handling in cruise/stalls/ect.

Gary

 

[scaleram]

I have a homebuilt cross between a Cub and a Cruiser. I have the throat set at 4.5 degrees. The rigging came off of a Carbon Cub, and I originally bolted it on and went flying. It flew OK but I thought I could get it to come off the water faster, so I cut the rear strut to give me the 4.5 degrees. It has a Cruiser wing that I converted to flaps, 180HP and an 86X38 Catto prop. It leaps off the water, but it is slow.

I am interested it the increased speed you get with vortex generators. What do you get in cruise while on floats?

 

[BC12D-4-85]

VG's haven't increased or decreased cruise speed much for me on several aircraft - before and after install. What helped me go faster with the PA-12 in Post #9 was removing the LE cuff. It's possible it was installed with the LE down too far by the previous owner so was draggy (bottom LE needs to be no lower than wing behind). Also, the stall behavior was milder with the VG's vs the cuff. With the cuff it would fly until it quit then dropped a wing or the other. With the VG's it just mushed and buffeted some. Similar speeds for both with the VG's a bit slower.

As far as takeoff most any PA-** with power and flaps does real good. Besides being fun to leap off the Earth's surface it's also nice to get somewhere soon before running out of fuel so cruise is important. That 4.5* would most benefit low powered aircraft w/o lift enhancing devices, and help avoid hitting the float heels on low speed high AOA rotation and landing. Again, any reasonable AOA and length of water surface and an angle less than 4.5* should suffice for Cubs that can use help in cruising faster.

Cruise on floats with cuff about 100-105 GPS at 2400 actual with 82/45 prop. Cruise with cuff off and VG's 110-115 GPS in my logs.

Gary