Amphib Float Controls

[dholly 718]

I want my Fat Bastard to float. Help me set up my Aerocet 1100 Amphibs here. 

[dholly 718]

The floats came with rigging for a Kitfox IV-1200. Here's a few pics of how the float controls were installed in that plane.

[dholly 718]

The bull (pulley) wheel on the KF is located within the fuselage, under the pilots seat. Unfortunately, the aileron mixer occupies the same space on the Avid+, making modifications necessary. About the only place to put it is under the right seat.

[dholly 718]

This poses some problems, first of which is interference with the flap handle. That was resolved by relocating the flap handle to left of center. A bit closer to the pilot's leg, but hopefully not a problem.

[dholly 718]

Here's how it looks with the flap lever relocated. Plenty of room now to mount the Johnson bar on the seat truss right of center.

[dholly 718]

Doug,

I was looking over some of the earlier conversation and saw your problem with the johnson bar.  Could you move it back onto the area between the seats?  Unless you fly with some very thin, people there's no way to get any left stick with the lever pulled.  Have you figured out where you'll put your water rudder retraction cable?  Going to be busy between the seats.

Good luck.

Jack

Two things I plan to do but haven't yet: I have to shorten the Johnson bar an inch or two. When put thru it's full motion, the clearance between the thumb button and the throttle bracket is too tight and you can pinch your finger. If that isn't enough, I'll have to futz with the stick offset or just make up a shorter stub stick for the right side control tube socket.

I did try to figure a way to put the Johnson bar between the seats like an emergency brake handle but just couldn't quite make it happen. Yeah it's tight but I think it'll work out where it is, another good reason to extend the control tube 3" rather than my originally planned 2-1/2".

Water rudder cable is tentatively planned to come up the center console. I have a couple possibilities in mind, one the simple handle and clip style and the other a lever system similar tto the original Kitfox style, but nothing set in stone yet.

[akflyer 1427]

holy crapanolies.. me thinks I am gonna stay on straight floats.. looks like it is getting busy in there.

Glad it is you and not me doing the work.  I am more into flying that tinkering and making stuff work!  Have fun with this project

[dholly 718]

holy crapanolies.. I am more into flying tha[n] tinkering and making stuff work!

Haha, lol! That's pretty damn funny coming from a guy who just spit-polished this "basket case"!

 

[akflyer 1427]

shnikeys... ya got me there... but in all honesty I do like the flying better!  I really enjoy the time spent on the rebuild though!  so much so, that I am gonna be brining in my wrecked Pacer this winter and stretch it, widen it, and make a fat bastard killer out of it

[dholly 718]

Leni - I'd take flying over wrenching any day, but with two in college and another starting pre-med next year I'm too darn broke to buy anything at the moment. Good thing I got friends who let me play with their toys now and again. I do like building, it's a good stress reliever from office hours and a lot of self-satisfaction in working through and completing each step. So I figure I might as well use what my wife has so fondly dubbed "the lean years" to put together a kit and have something to show for my time. Plus, it's a whole lot easier to sneak a plane into your garage in pieces. 

[jackak 20]

Wow!  Now I know what busy can look like!  You may need to raise the floor of your baggage compartment and put that pulley back there.  If its installed on the copilots side, it would turn the wrong way unless you crossed your cables.  If the cables exit the fuselage near the aft gear attach point, that could restrict your options too. May need to go with an electric setup.  Of course with an electric setup, you usually have a manual backup.  Much head scratching going to happen here.

Good luck on this one Doug.

Jack

[jackak 20]

Leni,

Is the pacer going to be an experimental or are you going to do or have an stc for all those changes?  Buying a fat avid might be simpler.  Is what you're planning called a Provider?  If it is, at least you'll have some samples to look at and people to talk to.  Sounds interesting.

Jack

[jackak 20]

PS, Heading for Arlington this morning, will check-in when I get back.

Jack

[dholly 718]

Hi Jack,

The gear retract cables do cross each other as they leave the bull wheel pulley before they pass thru guide supports and exit the cabin near each rear gear attach bracket. In it's original KF install, the pulley turned clockwise for gear down and counter-clockwise for gear up. In my install I have retained that orientation, so none of that changes. However, when positioning the pulley as shown in my earlier pics, the gear retract cables do not have a straight, unobstructed run to the rear corners due to seat bottoms and other misc. tubing members. It is, indeed, just a bit too busy to make for a quick 'n easy install.

Sooo, I think I've come up with the simplest of solutions... mount the pulley below and external to the fuselage under a small fairing. Clearly, this will make running the cables a snap. However, the latest potential wrinkle is my decision to use a 912 and here's why. I'm certain to use an underbelly radiator and, ideally, an underbelly air scoop (similar to the one Kitfox sells) that would also effectively house / hide the pulley wheel. Hehe, the 'ol two birds with one stone builder's trick. Just need to determine how that portion of the cooling system is installed to insure no conflict with the pulley or cables.

Whadda ya'll think? Any other ideas here?

[akflyer 1427]

Leni,

Is the pacer going to be an experimental or are you going to do or have an stc for all those changes?  Buying a fat avid might be simpler.  Is what you're planning called a Provider?  If it is, at least you'll have some samples to look at and people to talk to.  Sounds interesting.

Jack

Yes sir, going exp. with it.  I have a buddy that has one he stretched in 78, extended wings etc.  He has all drawings and STC for is, but i am just going to copy his drawings and fab per those for all structural mods.  other mics. clean up mods would be my own if needed.  Several stretch / widen jobs were done under various names.  The producer, provider, bushmaster etc.  This will be a mix of all of the above, dual seaplane doors etc.  Will be a several year project would be my guess.

[dholly 718]

This snip from the old Skystar install instruction manual shows the cable routing.

[dholly 718]

These pics show what needs fixin'. I think extending the control tube 3" will result in enough clearance for the right stick, still need to shorten the Johnson bar.

[akflyer 1427]

I am thinking this is the very first time I have ever heard a guy say he need, or wanted to shorten his johnson bar

Looking good, like the cardboard patterns!

[jackak 20]

Doug,

The belly mount idea sounds like it may just work.  Good luck.  A teleflex cable down to the pulley would be an easy way to connect it with your johnson bar.

Jack

Leni,

Your next project sounds like an interesting onem  An "experimental made from parts" is what they call them, I think.

Jack

Arlington was a let down this year.  Not much going on at all.  Very few planes and fewer vendor to check out.  But, the weather was good.  The economy?

Jack

[dholly 718]

Jack -

The J-bar must connect to the pulley wheel tower with a solid push/pull tube, no flexibility allowed. The gear retract teleflex cables run from the floats up through the rear struts, then to the cable brackets as shown in the install manual pic. I will need to locate both the pulley wheel and the cable brackets externally below the fuse. Plan is to have the pulley tower bolt extend into the fuse thru a curved slot in an access cover. The bigger issue becomes the potential interference between those parts and a belly radiator. I need to find examples of how/where these are most often mounted. I've seen some at the lower cowling outlet and some back further between the gear brackets.

Re Arlington: I bet the economy did have an impact this year, I have to pass on OSH for the first time in many years. I just can't afford OSH, a family vacation and a bunch of expensive airplane parts all at once this year. I'm not happy about it but I'd rather have the parts and keep building.

P.S.  Leni - gotta do what ya gotta do... trust me, it's only a problem when the gear is up!     

[dholly 718]

May need to go with an electric setup. Of course with an electric setup, you usually have a manual backup. Much head scratching going to happen here.

Good luck on this one Doug.

Jack

Well, after much head scratching, I ripped it all out. A thread came up on the kitfox list about converting the aerocet amphibs to electric actuators and I decided to go this route to eliminate the hassle of retrofitting the KF controls to my Avid+, freeing up cockpit room by removing that big Johnson Bar and the weight savings. Ron offered the info to the public so I'll share what he sent me. Thanks Ron.

__________________________

The changeover from cable operated to electrically operated Aerocet 1100 amphibs was my own experiment. The following illustrates my own experience and is not a construction guide. All of the materials used, except the actuators, came from my stash of scrap metals and spare parts and therefore are probably heavier and stronger than required. Still I saved cose to 2 lbs over the cable operated mechanism. All of the cables were removed from the floats. I never had installed the Johnson bar. The large control pulley was replaced by a lever 4 5/8†in length centre to centre. The small control pulley with the rest of the nosegear mechanism stayed in place.

I built an adjustable bracket – the adjustment part turned out to be not necessary.

The actuator I used is a Firgelli 8†throw, obtained on line, but there are other brands suitable. I made the mistake of buying an actuator with a built-in potentiometer, thinking I could mount a gauge on the panel indicating the position of the wheel. I discarded the idea when it came to me that if the linkage breaks the reading would show the actuator position but not the wheel position.

The bulkhead where formerly the cables were anchored was re-enforced with fiberglass and sheet aluminum, then notched at the top for the actuator to pass through and then the assembly was bolted on. Pic shows wheel up position.

The next picture shows test installation. I covered the actuators with appropriate rubber boots to protect against moisture. The electrical cables are long enough to reach just inside the fuselage where I used automotive receptacles to connect them with cables to the two way switch on the panel. This helps in quick removal of the floats for changeover to wheels.

To positively identify the up position of the wheels I installed a microswitch which is activated by a lever mounted to the idler pin (Part number 480-5042) of the main link (part number 480-6080-10) powering two LED lights on the panel. The microswitch in the picture will be replaced for the coming season by a waterproof switch since the one below shows some corrosion after only one season. The electrical cables are also equipped with receptacles for quick disconnect.

Finally I have installed a main retract system switch as well as the two way switch to avoid a problem if I accidentally retract or deploy the system on the ground. This would overstress and break the linkage. By the way, Datum Air, a manufacturer of wheel penetrating skis and conversion kits for electrically operated Puddle Jumper floats, is seriously thinking of developing a conversion kit for Aerocet 1100 floats. You can visit them on line www.datumair.com

[Trackwelder 12]

Looks like you have been staying busy, though it looks like one of those projects that takes forever and doesn't seem to amount to much. Keep up the good work and keep pictures coming.

[dholly 718]

The weight issue continues to eat at me. If I build super light and use the Jab2200 sitting in the closet, I know it will work but still wonder if I'll be happy with off the water performance. If I use a 912 or Sube I'll be underfloated, perhaps seriously and dangerously so. I've almost conceded to myself these floats which I bought for my Mk-IV are just too small for the Avid+ install. To make matters worse, I have had several fair offers on the amphibs and a buddy is selling a set of next-to-new Baumann 1500 straight floats only 45min drive away. Where's that winning Lottery ticket when you need it??

Decisions, decisions...

[akflyer 1427]

The weight issue continues to eat at me. If I build super light and use the Jab2200 sitting in the closet, I know it will work but still wonder if I'll be happy with off the water performance. If I use a 912 or Sube I'll be underfloated, perhaps seriously and dangerously so. I've almost conceded to myself these floats which I bought for my Mk-IV are just too small for the Avid+ install. To make matters worse, I have had several fair offers on the amphibs and a buddy is selling a set of next-to-new Baumann 1500 straight floats only 45min drive away. Where's that winning Lottery ticket when you need it??

Decisions, decisions...

Remeber that the 1100 is per float, so you will have a little fudge factor there. I know that most guys here put way more in the plane, especially the beavers and otters than the float is rated for. When there is money at stake, any float left sticking above the water is lost revenue

What is the weight of the baumann 1500 compared to what you have now? and what is the price differencial between what he wants and what you can sell yours for. I would be willing to bet the performance would be better on the baumanns versus your amphibs, but your main mission is what will be the deal breaker. Can you live with straight floats, or do you need the amphibs to keep it at the airport? You may be able to find a set of EDO 1320 that would be about perfect for you plane.

[dholly 718]

Leni - if the requirement for float certification is that it provide buoyancy of 80% in excess of the maximum certificated gross weight of that seaplane... using my 1320# x 1.8 = 2376#, divided by 2 = 1188# means I am at least 8% underfloated with an 1100 displacement float. On paper is one thing, real life another. The fact is, the displacement rating is for the straight, not amphib, floats. I have spoken to four Aerocet 1100 amphib owners, all Kitfox 4-1200, who say at gross the tips are super easy to submerge while taxi-ing and turning downwind. Great floats but hoping they can handle 1320# is likely a pipe dream. Sure, I would prefer amphib vs. straight floats, but straight floats over none! My shop at home is my hanger, the plane will be trailered either way.

I have not personally put everything on the scale but Paul Seehafer who owned both said he weighed the Aerocet straight floats, rigging and hardware at 158# and amphibs at 227#. The Baumann 1500s (1536# actual freshwater displacement) with Legend Cub rigging run 197#, lighter than EDO 1320s. I also like the Murphy 1500 straight floats but they are tough to find. I could probably swap to 1320s even or better, even to a couple grand more for the Murphys depending on condition and about +$4k for the Baumanns. They ain't cheap but have the extra lockers option and less than 150hrs use.