In a recent BCP thread, I learned that the Maule MX-7 gets an up-gross from 2500 to 2750 pounds when mounted on Edo 2440 floats.

I've also discovered that the kit-built Glasair Sportsman gets an up-gross from 2350 to 2500 pounds on (any?) floats.

What other aircraft get a similar increase in their maximum gross weight? Are those up-gross changes tied to specific floats?

Thanx, Dave.

P.S. - I particularly interested if Cessna 172's or 182's qualify for this up-gross benefit.

My understanding about many that get an upgross is because float gear is more durable than the wheeled gear it replaces. This is true of the Bearhawk which goes from 2500 to 2700.

And of course, as you noted, appropriately equipped Maules. My MX7 180hp plane isn't granted that upgross when on floats. But larger-engined planes can support the additional weight with power.

Any other insight?

~Chris

Check the TCDS for the aircraft you’re interested in. A lot of Cessna’s have a higher gross weight when on floats. My 180A on wheels has a gross of 2650. The TCDS for the 180 says the A model gross weight is 2820 on Edo 2870s, and 2850 on amphibious floats. Some planes, at least the Cessna 170, actually have a lower gross weight on floats, 2106 vs 2200.

Thanx Chris & Rob,

Since the C182 was never built by Cessna as a factory float-plane,
I doubt that it’s TCDS will have any of this info. Maybe the C172?
Anyone have a link to those documents, or knowledge from them?

BluNosDav wrote:Thanx Chris & Rob,

Since the C182 was never built by Cessna as a factory float-plane,
I doubt that it’s TCDS will have any of this info. Maybe the C172?
Anyone have a link to those documents, or knowledge from them?

I didn't see anything on the 182 TCDS about floats anywhere. The 172 looks to actually *decrease* to 2200-ish lbs on floats (Edo on the TCDS -- I didn't see any others).

http://rgl.faa.gov/Regulatory_and_Guida ... v%2014.pdf

I guess the rest are via STC from their respective vendors. Like for Wipaire (apologies for the formatting):

http://wipaire.com/aircraft_page/cessna ... wk/#floats

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Skyhawk Model   Gross Weight   Engine   Propeller
172, 172A, B, C, D, E, F,
G, H, I, J, K, L   2,220 lbs (1,007 kg)   Stock   Stock
172A, B, C    2,350 lbs (1,066 kg)   Lycoming O-360 (180 BHP) / Lycoming IO-360 (180 BHP)   ***
172I, K, L, M, N   2,300 lbs (1,043 kg)   172 I, K, L To have Penn Yan Aero STC SA332GL   McCauley 1A200/DFA8243 FP
172P   2,400 lbs (1,089 kg)   172 I, K, L To have Penn Yan Aero STC SA332GL   McCauley 1A200/DFA8243 FP
F172D, E, F, G, H   2,200 lbs (998 kg)   Stock   Stock
F172K, L   2,220 lbs (1,007 kg)   Stock   Stock
F172M, N   2,300 lbs (1,043 kg)   Stock   Stock
F172P   2,400 lbs (1,089 kg)   Stock   Stock
175   2,350 lbs (1,066 kg)   Stock   Stock
175   2,350 lbs (1,066 kg)   Lycoming O-360 (180 BHP) / Lycoming IO-360 (180 BHP)   ***
*** Propeller: McCauley 1A200/DFA 8243 FP, McCauley 1A200/WFA 8243 FP, Hartzell HC-C2YR-1BF/F8477-4 Constant Speed,
Hartzell HC-C2YK-1BF/F8477-4 Constant Speed

Seaplanes West STC does provide upgross while on floats for certain model C182 with certain engines

Thanx again, Chris!

Hale,
I visited the Seaplanes West website. Their up-gross STC also requires either reinforcing and/or replacing the wing struts on the C182. Some folks get this mod along with an engine upgrade, and some don’t.

Their up-gross STC may also carry over to use on wheels???

I’m not sure if you can get the up-gross while keeping the stock O-470 motor?

As you’ve likely deduced by now, there is no “stock” answer to that question.

In fact, the answer for a particular aircraft may lie in the Aircraft TCDS, or in the STC for installation of the floats, if those floats weren’t approved by the A/C TCDS, or as a result of a totally unrelated modification and it’s STC.

For example, the Flint tip tanks on the Cessna 206 increase gross weight from 3600 to 3800 pounds, on wheels or floats. Some other wing extensions for Cessnas do similar increases. Wip Aire changes the float attach points on some aircraft, and increases the GW.

Etc. Sorry, no pat answer.

MTV

The gross on the Aeronca Sedan goes from 2050 lbs to 2100 lbs when mounted on Edo 2000 floats. 50 lbs is easily eaten by the exchange weight, but it is better than nothing, or the decrease that a few aircraft get.

The 235hp Maules, M5, M6, MX7, M7, MT7, all get a 10% gross weight increase on floats which gives a very similar useful on floats or wheels.
100lb gear comes off, 350lbs floats go on. Gwt goes from 2500 to 2750lbs.
On M5's that have not had the gwt increase kit added, thus gwt 2300 on wheels, it goes up to 2530gwt on floats.