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Old 11-16-2015, 02:21 PM   #71
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Join Date: Oct 2009
Location: Junction City, WI
Posts: 646
Default Re: I still need float-rigging info

Hi Lynn,

Knowing how busy you always are, I figured you were just off on projects.

Yes, I agree that adding a bit more wing to float incidence will help your situation. Most would probably do that with my Kitfox, as it is pretty much the least amount I would ever put on a floatplane. But I like it the way it is. I'm certain however if I increased my throat angle on my Kitfox, I would shorten my takeoff run quite a bit. So in effect, my numbers are probably not the best to follow.

I think your idea of getting your time in the Cub would be a good one. Let's face it, most of these little airplanes fly best with just one person in it. The only thing I'd suggest is to incorporate your amphib ops training into your training program, even though the Cub is not an amphib. Just pretend it is so you develop habits that include proper gear position.

On that subject, I just read an article in digital Kitplanes talking about flying a Searey amphib,and the author explained Searey's new gear position warning indicator, and I really liked what they did. Granted I am really old school, so I will probably never go out of my way to actually buy one, but if I did I think I'd use theirs. I think they have it figured out.

I too hope people aren't discouraged by any of this float discussion, as yes, you are trying to do something that as far as I know has never successfully been done before (a Speedster Jabiru 2200 Kitfox amphib). And frankly, I'm impressed with what you have accomplished thus far. I think with more angle, along with those wing extensions (which will also be much more effective with the increased angle) that you will probably be happy with your new amphib. Especially if you can limit additional weight in the cabin.
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Old 11-18-2015, 06:54 AM   #72
Lynn Matteson
Join Date: Dec 2008
Location: Grass Lake, Michigan
Posts: 48
Default Re: I still need float-rigging info

Regarding my on-again, off-again training in the Cub, my instructor has me call out all the moves for landing as if we were in the Kitfox....that is: "wheels going up for water landing, pressure building ....mechanical indicators show all four wheels are up, and hydraulic pressure is maxed out on the gauges, mixture set (I've got a Rotec throttle body injector on the engine), flaps set, throttle back, etc, etc." He has me do this in the Cub even having to pretend that I'm looking at really IS good practice.

I ordered a new front fork to replace the damaged one, and while talking to Michael at Zenair, I mentioned that I broke the top ot the bulkhead near where the rigid end of the hydraulic cylinder mounts, then told him that this is a very weak area in their design, and that they ought to strengthen that area. He said that the people who buy their floats are very weight conscious....geez, what would it cost to reinforce that area? one pound per float would be a high figure, I'm thinking. The main wheels are built adequately, as far as I can see, but those fronts are weak right at the top of the bulkhead, where the flange is formed, and this is where the stress is concentrated.

When I was building my floats, I was narrow-minded enough to just follow the instructions and build accordingly. I DID do some modifications to the main wheel amphib apparatus, but never really looked at the front wheel mechanism with an eye toward how it worked and how the design put such a huge load on a very small area, to wit, the formed top of the #2 bulkhead. It would have been such an easy matter to have reinforced that area, and spread the load out over a larger area. Well, I forgot to put my "engineer's hat" on while building them, but you can bet that it'll be on while I'm RE-building them, and mabe even use a chinstrap to insure that it doesn't blow off!

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Old 11-19-2015, 07:38 AM   #73
Join Date: Oct 2011
Location: Jackson, MI
Posts: 155
Default Re: I still need float-rigging info

Hi Lynn,

I am building a set of 1450A's right now at 26W. I sent you an email a few weeks back regarding lessons learned from your build. I will look at the above mentioned areas, but would love to get together with you soon to get some advice from you. I can either meet you at your hangar or you can fly to 26W if you are out and about. I am on vacation all next week (Thanksgiving) except for Tuesday I have to work. I can work around your schedule. Thoughts?

-Mike Kraus
RV-4 built and sold
RV-10 built and flying
Radial KitFox SS7 built and flying
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Old 11-19-2015, 09:28 AM   #74
Lynn Matteson
Join Date: Dec 2008
Location: Grass Lake, Michigan
Posts: 48
Default Re: I still need float-rigging info

Hi Mike-
I'd be glad to see you and your floats. I have your number in my cell phone, and I'll get ahold of you next week to set up a visit. If the wind ever stops around here, I'll fly over there.

By the way, I just had a flash of brilliance about how to strengthen the "problem" area in the 1150 floats, and it'll probably work on the 1450, but not sure.

To people who may be following this thread, my #2 bulkhead gave way at the top, where it is bent to form the mounting flange. In looking at the crack, it is apparent that the metal there has been "working" for some time. My idea uses a different way to mount the "fixed" end of the hydraulic cylinder. I'm thinking this method out at the present. As it is, Zenair reinforces the hell out of the back face of the bulkhead, but all this "armor" is riveted JUST to the bulkhead, and the weak point is the bend that forms the flange, and that bulkhead is only 0.025" aluminum. The reinforcing doubler is also 0.025", and another piece of 0.090" sheet is riveted to that, making the reinforcing parts 0.115" thick. But this 0.115" "thickener" is riveted to the 0.025" bulkhead such that any force applied to the rigid end of the hydraulic cylinder (read: front wheels working up and down along runway/turf) is not braced by the whole 0.140" thick sandwich ( 0.025 bulkhead, 0.025 doubler, 0.090 reinforcing material) but only by the thin 0.025" bulkhead itself. I equate this scenerio to having a wall made of 1/4" plywood (the bulkhead) with no studs, then attaching a slightly smaller in size 3/4" plywood "reinforcement" to that, then having an offensive lineman smashing into the wall....eventually the 1/4" plywood bulkhead gives way. My idea would have the wall tied into the ceiling, so that any force against the wall is spread along the ceiling.

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Old 11-20-2015, 07:51 AM   #75
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Join Date: Sep 2013
Location: Port Severn, Ontario
Posts: 43
Default Re: I still need float-rigging info

This is something I came across a long while ago, although my floats are straight Aluminum. not Zenair though, hard to see some of the pics, but the rigging info might help you...
Attached Files
File Type: pdf Float installation kitfox.pdf (1.83 MB, 65 views)
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Old 11-20-2015, 11:37 AM   #76
Lynn Matteson
Join Date: Dec 2008
Location: Grass Lake, Michigan
Posts: 48
Default Re: I still need float-rigging info

Thanks for the info....yeah, the pics are hard to see after so many generations, but lots of good info nonetheless. I downloaded all pages and will print them out and add to my (ever-growing) file.
Thanks again....

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