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Float Update

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keystone(at)gci.net
Guest

Posted: Thu Mar 31, 2011 7:55 am Post subject: Float Update

John

I now have 3 years of float flying.  I have changed the front attach points and the angle of incidence every year.  The front attach points get stronger and the angle of incidence keeps getting smaller.  Because of changes in my life I will probably not be going on floats this year.  I retired and sold my home and am moving.  I will no longer have the hanger to hang the plane and still have changes I wish to make.  I am in AZ so I do not have access to my notes so what I am writing about is from memory.

I ended up re-making the front attach points again last year.  I took two pieces of angle iron and bolted them under the lower engine mounts.  I welded a ¾” pipe to the lower sections of angle iron.  I inserted a short section solid rod in each end.  This created a stable and strong front mount.  This is my third and final try at developing the front float attachment.  The front strut attaches to the solid part of the pipe.

I attached the struts to the floats the way Full Lotus recommended.  They are attached to the center of three longitudinal tubes in the top of the float.  The three tubes do flex both when the plane is in the air and when it is on the water.  It is noticeable but has not been a problem.

I did not have any direction on the angle of the struts so my front and rear struts are nearly vertical with a diagonal strut for stiffening.  This set up has resulted in  no issues I have noticed.

I still have not got the angle of incidence correct yet.  I first installed it with 6 or 7 degrees of angle of incidence.  The plane was slow in flight creating overheating problems which were solved by opening up more of the lower cowl to let the air out.  The stall speed was significantly higher than on wheels.  Every time I put it on floats I lower the angel and the plane gets faster and stalls slower.  Even with the problems it is quite a performer on Full Lotus floats.  

The flat bottom of the full lotus floats makes them a great performer but without a keel you cannot do step turns.  You can change the direction you are pointed but you are still traveling in the same direction.  It does do plow turns nicely although I need to keep the water rudder down.

Bill

N801BW

Time: 10:17:12 AM PST US

Subject: Float Update?

From: John Swartout <jgswartout(at)gmail.com>



Dear Bill,



You have some more float time on your Full Lotus floats now, and I have a

few questions.  I've got my new 10 ft. horizontal tail about done, and so

I'm back to looking at the firewall/cabin area to make sure there will be a

good strut attach arrangement before I hang the engine for (hopefully) the

last time.



Regarding the way the struts are attached to the floats, it looks like you

attached the struts at the center stiffener tube.  The CZAW plans show the

Zenair floats cantilevered outboard of the strut fittings, with the float

centers spaced 2.00m apart.  Did you keep that same spacing between floats?,

which would either splay the angle of the struts to the fuselage centerline,

or require longer struts.  Or did you keep the strut lengths and angles the

same, thus moving the floats closer together?  (I know you initially set the

reference line/float top angle at around 7 degrees, which would lengthen the

forward struts about 4", all else being equal.)



What is the diameter of the stiffener tubes?  I couldn't find it on the Full

Lotus website, and don't know if it's greater than the diameter of the tubes

in the 1450 or 1650 floats.  A guy who has mounted over 40 airplanes on

floats, including some Full Lotus installations, told me that these bigger

planes on longer Full Lotus floats should really use an "M" strut pattern

rather than an "N" pattern, to get the forward strut farther forward and the

aft strut farther aft on the float, minimizing the unsupported fore- and aft

sections of the floats and thereby minimizing flexing of the stiffener

tubes.  There is a picture of a Murphy Rebel using this arrangement at

www.lightsportaircraft.ca/murphy-rebel-pilotreport.html.   Have you found a

lack of stiffness in the floats to be a problem using the "N" pattern?



Finally, have you found a satisfactory fix for the forward top strut

attachment issue?



Thanks.



John

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jgswartout(at)gmail.com
Guest

Posted: Thu Mar 31, 2011 10:41 am Post subject: Float Update

Dear Bill,

  

 Thanks a million for the update.  After dozens of hours of analysis and several changes of mind, I'm moving in a similar direction with the front strut mounts.  Talked to Jeff Holomis a couple days ago about mounting options, and he suggested using the main spring gear instead of rear- and diagonal struts and cross wires.  Although that comes with a significant weight penalty (25 lbs, probably) it's fast, easy, rock solid, and if I don't like it it's a simple matter to make some more struts once I get all the angles right.  I wasn't planning for more than about 2300 lb gross on floats, so I guess I can make it 2325 for a while if I need to.

   

 I hope the changes you're experiencing are all good ones.  I don't believe I'd trade Prince William Sound for Arizona, given the choice, but life doesn't always go according to plan.

  

 John 

 On Thu, Mar 31, 2011 at 11:30 AM, BILL Wilcox <keystone(at)gci.net (keystone(at)gci.net)> wrote:

 [quote]--> Zenith701801-List message posted by: BILL Wilcox <keystone(at)gci.net (keystone(at)gci.net)>

 

John

I now have 3 years of float flying.  I have changed the front attach points and the angle of incidence every year.  The front attach points get stronger and the angle of incidence keeps getting smaller.  Because of changes in my life I will probably not be going on floats this year.  I retired and sold my home and am moving.  I will no longer have the hanger to hang the plane and still have changes I wish to make.  I am in AZ so I do not have access to my notes so what I am writing about is from memory.

 I ended up re-making the front attach points again last year.  I took two pieces of angle iron and bolted them under the lower engine mounts.  I welded a ¾” pipe to the lower sections of angle iron.  I inserted a short section solid rod in each end.  This created a stable and strong front mount.  This is my third and final try at developing the front float attachment.  The front strut attaches to the solid part of the pipe.

 I attached the struts to the floats the way Full Lotus recommended.  They are attached to the center of three longitudinal tubes in the top of the float.  The three tubes do flex both when the plane is in the air and when it is on the water.  It is noticeable but has not been a problem.

 I did not have any direction on the angle of the struts so my front and rear struts are nearly vertical with a diagonal strut for stiffening.  This set up has resulted in  no issues I have noticed.

I still have not got the angle of incidence correct yet.  I first installed it with 6 or 7 degrees of angle of incidence.  The plane was slow in flight creating overheating problems which were solved by opening up more of the lower cowl to let the air out.  The stall speed was significantly higher than on wheels.  Every time I put it on floats I lower the angel and the plane gets faster and stalls slower.  Even with the problems it is quite a performer on Full Lotus floats.

 The flat bottom of the full lotus floats makes them a great performer but without a keel you cannot do step turns.  You can change the direction you are pointed but you are still traveling in the same direction.  It does do plow turns nicely although I need to keep the water rudder down.

 Bill

N801BW

Time: 10:17:12 AM PST US

Subject: Zenith701801-List: Float Update?

From: John Swartout <jgswartout(at)gmail.com (jgswartout(at)gmail.com)>



Dear Bill,



You have some more float time on your Full Lotus floats now, and I have a

 few questions.  I've got my new 10 ft. horizontal tail about done, and so

I'm back to looking at the firewall/cabin area to make sure there will be a

good strut attach arrangement before I hang the engine for (hopefully) the

 last time.



Regarding the way the struts are attached to the floats, it looks like you

attached the struts at the center stiffener tube.  The CZAW plans show the

Zenair floats cantilevered outboard of the strut fittings, with the float

 centers spaced 2.00m apart.  Did you keep that same spacing between floats?,

which would either splay the angle of the struts to the fuselage centerline,

or require longer struts.  Or did you keep the strut lengths and angles the

 same, thus moving the floats closer together?  (I know you initially set the

reference line/float top angle at around 7 degrees, which would lengthen the

forward struts about 4", all else being equal.)



What is the diameter of the stiffener tubes?  I couldn't find it on the Full

 Lotus website, and don't know if it's greater than the diameter of the tubes

in the 1450 or 1650 floats.  A guy who has mounted over 40 airplanes on

floats, including some Full Lotus installations, told me that these bigger

 planes on longer Full Lotus floats should really use an "M" strut pattern

rather than an "N" pattern, to get the forward strut farther forward and the

aft strut farther aft on the float, minimizing the unsupported fore- and aft

 sections of the floats and thereby minimizing flexing of the stiffener

tubes.  There is a picture of a Murphy Rebel using this arrangement at

www.lightsportaircraft.ca/murphy-rebel-pilotreport.html.   Have you found a

 lack of stiffness in the floats to be a problem using the "N" pattern?



Finally, have you found a satisfactory fix for the forward top========

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