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Skis and floats

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Ultrapupflyin

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Aug 22, 2020
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80
as some of you guys on the forum know,I am finnishing a build I acquired at 90 percent done on a preceptor ultra pup,with a 2180 70 hp vw from greatplanes,as all your replies have been very helpful and have solved questions I've had,im asking for help on figuring out what skis,and floats would work on this airplane,it seems to have attachments for both,as its a 459 lbs plane I could only guess weight is a huge factor on deciding with floats and skis can be mounted,and all my internet searches have not yielded any results or even pictures of a preceptor ultra pup on ither,
 

Riggerrob

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Joined
Sep 9, 2014
Messages
1,584
Location
Canada
Most floats and skis bolt to existing main landing gear attach points. However, skis require additional attach point points for bungees (springs) to keep skis nose-up before landing. The forward bungees usually attach near the firewall, while aft bungees usually attach near the rear baggage compartment.
Similarly, floats require additional hard points near the aft cabin bulkhead.
 

Ultrapupflyin

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Joined
Aug 22, 2020
Messages
80
Ok and my plane has the mentioned attachment points but what I'm trying to figure out is witch brand or make,skis or floats would work
 

jedi

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Aug 8, 2009
Messages
2,207
Location
Sahuarita Arizona, Renton Washington, USA
For skies I would adapt a pair of old snow boards. Search the internet for metal floats of the proper size. They are out there and the airplane for them is no longer. There have been some good deals in the past.
 

don january

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Feb 10, 2015
Messages
2,902
Location
Midwest
The floats would have to hold up the GVW and enough HP to get up. Maybe a set of puddle jumpers that can handle the weight. As far as skies you'ed have to get the aircraft out on the snow and see if they will hold it up.
 

Riggerrob

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Sep 9, 2014
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1,584
Location
Canada
Snowboards will probably need additional stiffening ribs (wood and/or fiberglass) running fore-and-aft. If you make those ribs as high as wheel axles, you can keep propeller tips out of the snow. Take a look at production skis for suggestions.
 

Riggerrob

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Sep 9, 2014
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1,584
Location
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Go read Federal Aviation Administration, Technical Standard Order C27 to learn certification standards for production floats.
From memory, each float needs to be able to support 80 or 100 percent of the gross weight of the airplane.
... which means that you should start looking for floats with displacement of minimum 450 pounds. Displacement is measuring with the airplane sitting on calm water and fully-loaded .... similar to weight-and-balance calculations for wheeled airplanes.
Lotus makes inflated floats for ultralights.
A dozen other companies (e.g. Zenith) will cheerfully sell you aluminum or fibreglass floats specifically designed for the lighter weights and lower airspeeds of ultra-lights.
 

Mad MAC

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Joined
Dec 9, 2004
Messages
685
Location
Hamilton New Zealand
Technical Standard Order C27 refers to NAS807 which isn't free, same again for the skis TSO C28.
However the preceding CAR document is available, can't remember what one it is exactly, may be in CAR 3.
 
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