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float rigging

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peterc(at)pipcom.com
Guest

Posted: Mon Mar 12, 2007 8:16 am Post subject: float rigging

Is anyone aware of any significant document that  goes into detail on the various aspects of hanging floats on an  aircraft?

 I've heard the assorted rules of thumb about step  placement and angle and have successfully mounted floats before but I'm curious  about what is behind some of the ideas and the affects of deviating from  them.

  

 For example one formula says mount the step 1/4 (or  1/3) of the WIDTH of the float behind the cg. Where does this come from? How  does float width affect this?

  

 Another says mount the step so as to intersect a  line drawn 6 degrees aft of the cg. This imples that height of the rigging  affects step placement.

  

 What are the factors affecting height above the  floats?

  

 Why is loading never mentioned? In other words  wouldn't the step position be of more interest to the cg at gross than empty  cg?

  

 Surely there is a reference book on this somewhere.  I was not successful with google searches.

 Thanks

 Peter

   [quote][b]

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Mon Mar 12, 2007 10:29 am Post subject: float rigging

the recipe I use for locating  the installation point for floats is:

  

 *Obtain one  float

 *Obtain a small body of water  .

 *Put the float in the body of  water.

 *Start filling the front  compartment of the float and continue until the float  floats level.

 *Remove the float from the body  of water.

 Now it gets  tricky

 *Obtain a stick about two feet  long and 4'-10' in diameter ( about the size of a nice stove billet  )

 *Rest  the float on the  stick so the stick supports the keel of the float and roll it ahead until the  float is balanced.

 *Measure the distance back from  the front of the float the stick is.

 *drain the water out of the  float.

 *Mount the floats so the CG of  the plane is the same distance back from the front of the floats as the  measurement tow steps ago.

  

 Install the float so the AOA of  the plane is about 1-3deg up.

  

 No mixing  required

 No oven stove or  refrigerator

  

 Also no ballast required to get  the plane up on step.

  

 Weakness of  recipe:

  

 For planes that are tandem  seating the overloading of the back seat will cause the tails of the floats to  sink.  For such planes put the CG over the balance point of the floats when  the plane has a medium load...with the landing gear  removed.

  

 The whole idea is to get the  plane to float more or less level at rest in the water.

  

 There are some who  intentionally float planes like the super cub with too much weight  forward.  These planes require carrying ballast in the back seat to enable  the plane to get up on step.  They also enable the plane to carry a  whopping big load behind the pilot.

  

 

Noel [quote]   

   --

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

cathyboone(at)softcom.net
Guest

Posted: Wed Mar 14, 2007 8:25 pm Post subject: float rigging

Not aware of any document, but you might try to  contact the folks at Kemore Air Harbor in the state of Washington.

 [quote]   ---

peterc(at)pipcom.com
Guest

Posted: Fri Mar 16, 2007 11:07 am Post subject: float rigging

Larry I tried Kenmore but thay had  nothing.

  

 Noel's method sounds interesting and I plan to try  it when the ice goes out.

  

  After asking around I now have five  approaches for locating the step relative to the cg:   One was a  fixed distance for my particualar plane (which has worked in the past but puts  the step closer to the cg than the other methods);  another used the 50%  chord point (and was argued strongly by a long term aircraft and float  designer); another puts the step on a line 5 degrees aft of the cg. another used  1/3rd the width of the float; and , finally, Noel's method  to calculate the center of bouyancy of the float.  There is likely a  similar bases for Noel's and the 1/3 width method which may also be related to  center of bouyancy.

 No one that I have  asked has ever seen any document on this.

  

 Peter

  



   [quote][b]

d(at)cfisher.com
Guest

Posted: Fri Mar 16, 2007 11:17 am Post subject: float rigging

Peter, I had posted this on another list earlier  and he has some downloads on that site wtih some info that might help you  .

  

 Dave 

  http://www.cfisher.com

 more flying stuff ........



  

 You  glass guys have most likely run into a set of these floats, very  

popular with the SuperCub guys.

Well a little big for Kitfox  but  these are my neighbour's  product and 

becoming very popular.



http://www.clamarfloats.com



It has  been very popular so far and now a 3500 will be dressing up the 

Murphy  Mooses this year.  Look  for him as Sun n Fun if you are  going.

After seeing the results,I would say that these have proven to be one  of the 

toughest floats on the market now.



I flew in  there on  Monday this week with 16 inches now - now it about 95% 

gone.



And  before you ask , he wil not be making anything under  2200s unless you  

are willing to pay 25k for striaght floats. Personally I think there is  

market for a 1400 to 1600 float for LSA stuff and there are some new ones to  

surface in the next year or so.

That being said the Aerocet 1100s a  decent float  but could affoard to be a 

little bigger displacement on  the heavier Kitfoxes.



What would you pay for a set of floats ?

1400s  straight or amphib ?



Dave

 http://www.cfisher.com

 more flying stuff ........

 

 

 [quote]   ---

cathyboone(at)softcom.net
Guest

Posted: Tue Mar 20, 2007 4:52 pm Post subject: float rigging

Peter,  I'm glad you are putting some effort  into the research. I only have about 200 hrs on floats and most of that is in  Alaska flying for an outfitter. Half of the time (taking clients out) the plane  was loaded very heavy and of course the weight was is the back. I can only think  of two times I had to load the float compartments. By the way, I am putting  together an S5 and eventually want to take it to Alaska on floats. I believe if  I had a choice, I would favor the CG to the safest point forward on the floats  because of the tendency to pile in gear to the aft. This includes long items  tied on the floats. But I don't suppose you will be using the kitfox this way.  Another consideration is how the plane actually handles forward and aft loading  of the CG on wheels. Remember, I am used to maximum performance of the aircraft  because of the generally cooler weather up there and I have not flown the  kitfox  in any configuration except for a demonstration flight with  tricycle gear in Caldwell during the summer. Good luck and keep us  informed!

 [quote]   ---

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Tue Mar 20, 2007 5:47 pm Post subject: float rigging

If I read the documentation on  my modIII-A  the weight is furthest forward at the lightest load.  In  my case that was empty tanks and a 140lb. pilot.  I don't know any one who  flies in this area and weighs in at 140.

  

  

 

Noel [quote]   

   --

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

cathyboone(at)softcom.net
Guest

Posted: Tue Mar 20, 2007 8:43 pm Post subject: float rigging

Yes, and that was my point. The cg should probably  as far forward as safely possible when the aircraft is lightest. Then as the  load gets heavier the cg moves aft. This affects the performance of the plane  getting on step quickly.  As a general rule, the quicker you can get on  step the better.

 [quote]   ---

peterc(at)pipcom.com
Guest

Posted: Wed Mar 21, 2007 4:46 pm Post subject: float rigging

The point about setting up for good performance  with an aft cg is sounds reasonable. We have all likely experienced having to  move forward in an outboard boat to help get it up on plane. However, a friend  pointed out that perhaps the best route is to rig for the most common loading  which may be one person and little baggage. Guess it all comes back to personal  preference.

 One thing I have noticed with two Rans S-7's I've  owned which were both rigged with step just a little aft of empty cg is very  little tendancey to nose down after touch down. With all ther other certified  planes I've flown especially Cessnas is the need to be ready with up elevator  after touch down; the Rans needed very little of this.

 Peter

   [quote][b]

Malcolmbru(at)aol.com
Guest

Posted: Wed Mar 21, 2007 6:31 pm Post subject: float rigging

I really enjoy the chatter about float flying and such I have completed my  zenair floats but don't expect to install them for a while. I still need to  build a trailer and then reg them to my model 2.  i have flown several  plans on floats and also watch the kolb site,  they are talking about Jim  lee now and some of the  paten's he had for float flying  Please keep  up the chatter I really enjoy it  mal Michigan kit foxer  



AOL now offers free email to everyone.  Find out more about what's free from AOL at AOL.com. 

  [quote][b]

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Wed Mar 21, 2007 7:01 pm Post subject: float rigging

Come  back next month when I get my 'Fox in the water!  

  

 Darned  cold here tonight Blizzard this morning  no float flying for a few weeks  yet.

  

 G' night  all

 

Noel [quote]   

   --

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

cathyboone(at)softcom.net
Guest

Posted: Fri Mar 23, 2007 8:56 pm Post subject: float rigging

Peter,

 I would encourage personal preference from the  standpoint of being comfortable and cautiously confident. Do the floats you have  in mind give you much leeway in rigging? Is there room for  experimentation?

 [quote]   ---

peterc(at)pipcom.com
Guest

Posted: Sat Mar 24, 2007 5:55 am Post subject: float rigging

Peter,

I would encourage personal preference from the standpoint of  being 

comfortable and cautiously confident. Do the floats you have in mind  

give you much leeway in rigging? Is there room for  experimentation?



 Hello Larry.

  

 Yes, making changes to rigging is a pain and  expensive. With the jig I'm building, Ill be able to set up a new set of struts  without messing with the current set. Hopefully by starting out with a slightly  higher and forward cg setup, I'll be able to modify (shorten) one  set  to get slightly lower and more aft cg. The streamline tubing I'm  using has a thick internal flat which lends itself to changes to the  angle at which it contacts the fitting.

  

 This could all be talk once the flying gets  started.

  

 I did locata a naca report on some experiments from  1928 but I'm finding it difficult to make sense of.

  

 I'll also be selling  rigging to fit the Rans  S7 (and maybe the S6 once I get dimensions and modify the jig).

  

 Peter

   [quote][b]

raymondj(at)frontiernet.n
Guest

Posted: Sat Mar 24, 2007 7:30 am Post subject: float rigging

Peter,

  

     I'm interested in getting the naca reports you  mentioned.  Where did you get them?

  

 Thanks,

 Raymond Julian

 Kettle  River, MN

 [quote]   --

peterc(at)pipcom.com
Guest

Posted: Mon Mar 26, 2007 6:25 am Post subject: float rigging

Raymond

 Here is a one search although I  haven't downloaded this one yet. If you search on flying boat or amphibian  you will get some hits.  http://ntrs.larc.nasa.gov/search.jsp?N=0&Ntk=all&Ntx=mode%20matchall&Ntt=%22small%2Bflying%2Bboats

 The one I did get was by H Herrmann from 1938 on  twin seaplane floats but the document is hard to relate to our situation  (for me anyway) 

 Peter

   [quote][b]

raymondj(at)frontiernet.n
Guest

Posted: Mon Mar 26, 2007 8:59 am Post subject: float rigging

Peter,

  

     Thanks for the link.

  

 Raymond Julian

 Kettle  River, MN

 do not  archive

 [quote]   --

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