Seems like for any pair of floats you find, the rigging on it could be what you need...or not. At first glance it's just streamline tubing bolted to attach fittings, but obviously the money's in the intellectual property of the measurements of those tubes to achieve the ideal geometry for a float installation on a given type. Kenmore will not show you drawings for rigging. They won't tell you strut lengths.

If a guy were rigging his self-designed experimental though, where would he start? Is there a rule of thumb for spreader width? Strut length fore and aft? Are you looking for some perfect ratio of triangle between the three? How about AOI of float to wing?

Is any of this stuff documented anywhere?

Probably go copy a set from a Maule or whatever is the most similar to your Bear Hawk?

Ross4289 wrote:Probably go copy a set from a Maule or whatever is the most similar to your Bear Hawk?

There are a few community members I can lean on for that. I'm more curious from a general sense. When our your ancestors here in early Minnesota first rigged float planes, what were they looking for? Some rule of thumb AOI? A set spread on the hulls? Why is Kenmore so protective of this information?

It's keeping me awake at night.

I’ve never rigged floats, I think I’ve only seen a set a handful of times in my life, but I’ve rigged new fertilizer spreader and spray booms on ag plane’s several times. Easy rule of thumb is 3 degrees more AOI for the attachment than what the wing is. I’ve used a level app on my phone, found the wing to be at 12 degrees, adjusted the fitting for the spreader/booms to be 15 degrees, adjust the brackets and done. The thinking is the extra AOI will help the attachment carry it’s own weight and not be purely drag, and it works quite well. I had a Swathmaster on a 450 Cat that was downright terrifying to fly with a load in the summers, sometimes it couldn’t cross a set of powerlines with a load. It was set 6 degrees negative to the wing, adjusting it correctly felt like it gave me another 200 hp. Don’t know if any of that applies to floats though.

CenterHillAg wrote: It was set 6 degrees negative to the wing, adjusting it correctly felt like it gave me another 200 hp.

That's wild. Seems like something they should add to the ag pilot curriculum.

If you can find someone with a set of Montana floats, find out what their rigging specs are. I know Keith spent years, adjusting a little and flying, taking performance readings, and then doing it all over again. He used a Super Cub, Pacer, and a Citabria. I wish he was still alive, because I'd really love to go pick his brain some more. He was a good guy and always pretty willing to share knowledge.
John

Of the various "after market" floats I like the Montana ones, most of the others look like they are skinned with tinfoil.

Incidence between wing and float is very important. The early aircraft speed records were set by aircraft on floats. They had a very low incidence and took forever to get into the air. Increase the Incidence and you get off the water quicker but you will loose top end speed. Depending on the type of floats you can adjust the incidence at the float to strut interface with washers or plates to change the incidence a few degrees. It is not uncommon to change the length of the rear struts for the the same effect. HOWEVER, be careful you are hanging a lot of surface area out that can be effected by the prop and airflow every float is going to be different so just because they work on one type of aircraft they may not work as good on another. Go to Supercub.org they just did a good thread about rigging floats.https://www.supercub.org/forum/showthre ... at+rigging
DENNY

DENNY wrote:Incidence between wing and float is very important. The early aircraft speed records were set by aircraft on floats.

That is fascinating. I guess they're just super stubby wings with really long chords

Zzz wrote:

CenterHillAg wrote: It was set 6 degrees negative to the wing, adjusting it correctly felt like it gave me another 200 hp.

That's wild. Seems like something they should add to the ag pilot curriculum.

The aerial application world is so diverse that somethings tend to be completely foreign from one region or commodity to another. The best spreader practices and knowledge still come from areas heavily skewed towards dry work, but CHA's 'rule of thumb' is in fact now in the National Pesticide Applicator Certification Study Guide which has to some degree bridged the knowledge gap and functions well as a study guide for state level 'Core' exams.

And yes, I think most guys who've done it a bit have run in to mis rigged vs well rigged spreaders. Airplanes with poorly rigged spreaders don't even like to fly empty. For a real treat, sometimes you might have only a load or two of dry work and leave the all spray gear on in addition to hanging the spreader... now that's a. real joy to fly


Take care, Rob

I think it was more that the floats acted like a lifting body and massive HP for the day helped a lot. https://en.wikipedia.org/wiki/Macchi_M.C.72
DENNY

Another example that eventually morphed into a "reasonable" WW2 fighter

https://en.wikipedia.org/wiki/Supermarine_S.4

Rob wrote:For a real treat, sometimes you might have only a load or two of dry work and leave the all spray gear on in addition to hanging the spreader... now that's a. real joy to fly

I did that once, I’ve seen bricks with better aerodynamics.

http://www.stoneylake.org/pipcom/floatgeo.htm

I thought this was an interesting read on float rigging. Maybe it’ll help.

ljhpete wrote:http://www.stoneylake.org/pipcom/floatgeo.htm

I thought this was an interesting read on float rigging. Maybe it’ll help.

I found this link while Googling this morning and came back to update this thread, but you already did! Good find.