Plan built floats

[Ultralights]

I have been scouring the net for plans built floats suitable for a

 

Ch701/savannah/CH601, unfortunatly i cannot seam to find any, sure

 

there are plenty of complete floats for sale at approx$6000 US, but i

 

am after plans built versions, are their any available? and if so,

 

where?

 

Thanks

 

 

[TechMan]

I dont know of any kit or plans built floats.

 

There is no design standard for 'ultralight' floats as such, it is being developed at the moment.

 

At the moment it is still 'hit n miss' with building your own. There

 

does not seem to be much info out there on floats for very light

 

aircraft.

 

Perhaps have a chat to Howard Hughes as he builds them for his Lightwings.

 

Chris

 

 

[pylon500]

<div style="">You could be right!?<div style="">I thought Zenair manufactured 'kit' floats, but their site now only shows finished ones?<div style="">http://www.airplane.cz/pages/floats.htm

 

<div style="">You could try here to make some wooden floats;<div style="">www.ultralightfloats.com/index.htm<div style="">This link will give you an idea of building a set of glass kit floats;<div style="">www.ultralightfloats.com/PDF%20Files/Composite%20construction%20instructions.pdf

 

<div style="">Try this site and go to the 'Float' link;<div style="">http://www.aerocompinc.com/<div style="">Other than that, as you say, there's not much out there?<div style="">I could suggest that if you are down the Bankstown way some time, drop in and have a look at some BIG floats (under Beavers) to get some ideas for making your own!<div style="">Arthur.

 

 

[Guest Fred Bear]

Email me if you are interested in adding floats to your aircraft.

 

I know of the location of 2 sets which are available in Victoria. One are solid and the other are inflatable.

 

Clem [email protected]

 

 

[Ultralights]

I rang Zenair, the floats they havea re Kit only, they will not sell

 

plans, i rang Chech aeroworks who manufacture the float kits, again, no

 

plans availible for sale. sadly the budget with the purchase of the kit

 

and engine doesnt stretch far enough for a complete set of loats, unles

 

i can get a real cheap set made of aluminium that need repair??

 

 

[pylon500]

Without really knowing some-one's capabilities, I wouldn't usually

 

make the following suggestion, but if you are building something in

 

metal, I would think that by the time you have fininshed the plane you

 

may have enough idea to be able to design and build your own floats.Study carefully any pictures you can find of the Zenair floats, or P.K. brand floats, and see how they are put together.Basically you end up with a sort of flat, upsidedown pentagon section that can all be made from flat sheets, no compound curves.The hardest part is the step, all else is just straight fold bulkheads, flat sheet and angles.You may need to look into a 'shrinking' tool for the side angles, (will cost about $300.00) but a real handy tool.Most rivets can be solid, and 6061 sheet is fairly available.Arthur.

 

 

[Guest micgrace]

Hi

 

Try this www.ultralightfloats.com Plans available (wood) plus float kits in fibreglass

 

You

 

could get a set of plans and modify them to suit 6061T6 The hardest

 

part will be doing compound curves. You could usea beanbag and dolly

 

plus english wheel for compound curves works BUT if much work for

 

formingmay have to use lower spec 6061T4 adjust thickness accordingly.

 

Fill with blow foam when finished.

 

Micgrace

 

 

[Ultralights]

thanks for all the help, i have no problem with working with metal, i

 

am an aircraft structural fitter by trade and work on evrything from

 

B747's to F18 Hornets. the main reasen for the plans option is i can

 

take them to work and build them during periods when work is quite.

 

Thanks for the links, im looking into them all, and the timber plans option looks like the most likely,

 

my last question, is displacement, does the displacement of the floats have to exceed the MTOW of the aircraft (obviously) but is there a percentage the displacement but exceed the MTOW by?

 

eg Savannah MTOW is 992 Lbs, Float displacement range 800 bs to 1200

 

Lbs. would floats of this displacement be suitable or is a larger rated

 

float required??

 

Thanks in advance.

 

Rob.

 

 

[Guest micgrace]

Hi

 

I'd work out the volume occupied by the lower 50% of the floats (that may be somewhat tricky unless your a bit handy with calculus and very few actually understand that). The amount of water displaced (MTOW) should be equal to the volume.

 

Do all calculations in metres/kilograms. fresh water weighs 1000 kg per cubic metre (approx, but close enough). More for salt water. Don't bother with that, stick to fresh.

 

So if the MTOW is, say 600kg the volume should be 0.6 m3 or 600lt (also 1 kg per litre)

 

So long as the floats exceed that by a long margin, I'd consider 2:1 barely acceptable 3times muchbetter i.e. depth floats sink in water to height.

 

I wouln't want to go over that ratio of displacement to water height on floats. The less % of the floats in the water (less wetted area) the better.

 

Possibly the best design would have a fairly broad beam and base, bit like a speedboat so it gets up on the "plane"

 

I'd say, you could even dummyit up as an airboat to see what happens. Could determine the thrust to get planing and other problems.

 

Hope that helps somewhat.

 

Micgrace micgrace

 

 

[pylon500]

i am an aircraft structural fitter by trade

OK, Well floats aren't real hard for someone like us!

Below is a basic concept for float construction.

 

For a CH701 you are going to need floats around 4.5m long, about 500m/m wide at the step and about 500m/m deep at the same place.

 

A ball park guess for a step location is about half a wing chord behind the centre of gravity, with the rear underside of the float tapering upwards at about the same angle that you would climb at, (the idea is to not touch the rear in the water as you lift off)

 

As for materials, I would use 6061-T6 sheet, cheaper and better corrosion properties, don't use commercial alloy (5XXX series), not strong enough.

 

You will need to have access to a 'shrinking' machine, to curve the angles joining the side skins to the hull and top panel.

 

When drawing the lower bulkhead, keep the 'V' angle the same on all corners, just scale down for width and height.

 

For your weight, make the internal channels and frames from .032", skin the sides and top with .025", skin the front hulls with .032" but the rear hull with .025".

 

If you can make the rear hull skin in one peice it will be lighter.

 

To create the step, rivet some angles on the back of the 'step' bulkhead about 50m/m parrallel above the lower flanges.

 

The 'keel' for the front hulls would have to be folded to match the 'V', probably from about .040", then shrunk on each side to create the 'bow' shape.

 

The top corners of the floats would be the same method.

 

The 'chine' angles, joining the hulls to the sides can be extruded 90° angles, try some 20x20x3.0m/m commercial which will be rivetted on the outside which means the hull skins need to be wider than the sides.

 

Locate a bulkhead about every 500m/m, with each second one having a .025" skin rivetted between the frame angles to create seperate floatation chambers.

 

This is all the easy bit, :;)2: after this you will have to figure out how to attach the floats to one another, and to the plane.

 

Then figure out hjow to fit a water rudder(s), how to pump out leaks (trust me you'll get them!) andhow to make up some form of 'bumper' to put on the front of each float? ;)

 

Buy a moulded rubber basket ball, cut it in half and screw onto some heavy angles rivetted to the front bulkhead.

 

You could also rivet some external angles on the underside of the forward hulls for a bit of directional control and to control side spray.

 

Have a look around and you'll get some ideas...

 

Arthur.

 

 

[Guest scottperkins]

I bought a set of plans for an all aluminum float

 

15 years ago that is probably 30 or 40 years old.

 

They were blueprints for the North-Aire brand floats.

 

Wisconsin USA I think.

 

It is stated that they are for 1200 or 1500 pounds but

 

I dont know if that is bouyancy for each float

 

or recommended empty total plane weight.

 

What needs to be done is these loaded into a CAD system

 

so that they can be shrunk and enlarged by a percentage

 

amount to suit a particular airplane. This could be done

 

in a few seconds and then be printed.

 

I dont know how to attach images or I would show a

 

photo of these plans shrunk to 15 percent of original

 

size and also some full size notations and bill of materials call outs. I had them scanned by a commercial

 

engineering firm as the paper is quite large at

 

64 by 36 inches.

 

Scott- Atlanta, Georgia USA

 

my email is [email protected] as I may

 

not be checking here too often.

 

 

[Guest scottperkins]

The design of float bottoms is a tradeoff of

 

efficiency verses the ability to handle rough and

 

choppy water. The very most efficient is a perfectly

 

flat bottom like in a swamp airboat. A Deep V

 

requires more power to plane but slices through

 

choppy water.

 

The reason why each float must be at least equal

 

to the weight of the total plane is when the

 

wind blows sideways on the plane a single float

 

can submerge if it cant hold it all up by

 

itself.

 

Scott, email info= ( 2scott at bellsouth.net )

 

..

 

My Email

 

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