Printable View
Hey Guys,
I have a really nice 4 with a 637 empty weight and a 1200 gross. Long wing and rotax 912UL engine, small tanks. Grove gear, 21/1200 2 ply tires and a Matco 6" tailwheel
Two questions:
1. How much weight will I loose pulling off all the gear?
2. Best Amphib float size? I am considering the Zenair 1450 or 1150 (1250?)
I plan to build the floats myself and solid rivet them.
Thanks for the input!
Christopher
I think,after reading...the 1150 are to small for 1200 lbs plane like your's and mine..the best would be 1250 or 1300...but some guy's said it a great float plane with 1400 zenair...
Hope it is help ...:confused:
The reason I said 1150(1250) is because I talked with Mike at Zenair and apparently the 1150 floats are really 1250 floats.
If you look at the website under "Float sizes" then "Overview" there is a note to this affect in the very first paragraph.
So, I guess they are really 1250 floats..... That being said, 1250 or 1450?
I would hate to carry an extra 20 lbs of floats if it wasn't necessary.
1150 amphibs are 90lbs each
1450 amphibs are 100lbs each
I was figuring 50lbs for rigging and hydraulic pump.
So, empty weight 637 - 70?(gear) = 567 + 250(floats) = 817 + 81(full fuel)= 898
1200 - 898 = 302 - 150 (me) = 152 for a passenger.
Sound about right?
I own a Model 4 1200 long wing float plane with a 912ul Rotax. It flies and performs absolutely great, but the Aerocet 1100 floats are slightly small. But even though the floats are a bit too small I like my Kitfox as it is, and choose to accept floats that sit a bit low in the water as it performs exceptionally well overall.
However, if I was to do it over again I would go for a slightly larger float. Having experience with the 1200 / 1250 Czech built amphib floats (improved copy of 1150 Zenairs) on a couple different airplanes at flying weights as high as 1500 lbs, I can tell you they would be a great choice for a Model 4 Kitfox. For the money, they would be my 1st choice.
To qualify that opinion, I have over 1400 hrs of seaplane flying, split between Avid Flyers, Kitfoxes, Just Highlanders, a few Rans S6 and S7's, a handful of antiques like Cubs and Champs, a bunch of Cessna and Pipers, and my own Lake amphibian. Plus I run Eaa's Seaplane Base, so I like to think I have pretty much seen it all; the good, the bad, and the ugly when it comes to seaplanes.
And yes, a 1450 Zenair would also work, but in my opinion are too large for a model 4. As long as you keep your Model 4 under the 1500 lb weights I've flown the 1200/1250 float up to, they will work great. And honestly, one shouldnt have any reason to fly a Model 4 at weights that high, so why carry around the extra weight, and even worse, the extra aerodynamic and hydrodynamic drag associated with the larger 1450 float? (Fwiw - my Model 4 has flown just fine up to the LSA limit of 1430 lbs, but I traditionally try to stay under 1320 as I feel flying only 10% over design gross is much more reasonable).
Now, if you plan to fly over 1500 lbs buy the 1450's. So a newer, bigger, heavier Kitfox will be better served with the larger float. But, if you find some 1200/1250's and you have a 750 lb or less EW Kitfox 5, 6, or 7, they will work very well up to the LSA max seaplane weight of 1430 lbs. At least that has been my experience.
Oh, and I'd guess your gear removal will be between 50 and 60 lbs. So I think your calculations are pretty close. Typical float weight gain is around 200 lbs for the 1200's, after gear removal (Maybe a bit less gain since you have a heavier Grove spring gear vs bungee tube style?) Typical Model 4 on amphibs is approx 800 lbs.
Paul Seehafer
Paul,
Thanks for the info!!
What I have is a bit of a hybrid plane. My serial number is 1151, which is a model 3, small tail. However, before the plane was built it went back to the factory and had the Denny Aero seaplane mod. The unbuilt 3 wings were changed out for model 4 wings and the HD struts (1" diameter). The original builder gave it a 1200lb gross weight. So, I call it a KF 3.5.....
From what I gathered of your info, it is not terribly unsafe to operate above the 1200lbs? From my numbers I would need like 50 lbs to carry my father with me... If I used the 1320 number as my max, I would have plenty of useful load.
Would it be possible to give you a phone call? If you don't mind, please send me your phone # and I will give you a call.
Thanks!
Paul,
Yes, thanks, I will get the rigging components from Zenair.
What I don't know about is how to actually set the height, spread, and angles for the floats.....
Christopher.
One last thought; a bunch of years ago a friend did a pretty scientific test to a 1250 amphib float to determine its true buoyancy, and found it was just over 1300 lbs. That's why we believe they renamed them 1250's. To compare them against an 1100 Aerocet, the Aerocet is 2 ft shorter and about twoinches narrower. For anyone that can do that math, that makes the Aerocet 1100 a true 1100 lbs of max bouyancy, but compared to the 1250's at 1300 lbs true buoyancy each, each of those floats supports an additional 200 lbs vs the Aerocet. And yet the Aerocet works well, even though a bit too small. So again, the 1250 is better sized for a Model 4 than the 1450 imho.