Anyone have a Zenith 701 or similar, on floats, that they land at high altitude on tiny lakes?

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TheToad

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I'm thinking a tiny STOL floatplane would be awesome for alpine lake camping in the Sierras... But wonder how small of a lake is sufficient at elevations of 7-10 thousand feet elevation... I'm kinda eyeballing a few that are between 500-700ft length range... Anyone doing stuff like this?
 

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JMyers1

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I am also interested in performance at high altitude for a 750, which is probably in the ballpark of a 701 with floats. I'm stuck between the ULPower 4 cylinder, 6 cylinder, and the Lycoming YIO-233. Anemic climb rates in the mountains are terrifying when it is windy, which is most days.

The 6 cylinder is overpowered for a 701, but with floats at altitude I would think it would be more than sufficient if you are OK with a $30,000 engine. I don't know about the engine mount handling the power at sea level, probably fine.
 

davidb

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Weight is a big factor when getting off the water. You will want a turbocharged engine for sure. Takeoff distance will be double what it is at sea level even if the turbo is giving you the same horsepower.
 

TFF

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One of the latest Trent Palmer videos is in the STOL “racing” in Reno. You can look at the performance of regular planes at altitude.

If it will do it, I bet it takes every foot of the lake at 7000 ft. It might be more of what type of approach and departure routs you have. If all you have to do is break water, maybe ok. Clearing a 50ft tree line is asking a lot.
 

davidb

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That performance would “comfortably” fit in 500 feet but assume it is very lightweight with a bit of a headwind at sea level.

As a point of reference, a lightly loaded SeaRey could match that performance. But, at 8000 ft density altitude and closer to gross weight the takeoff run is about 1000 feet on water but much less on pavement.

The turbocharger addresses the obvious issue but less obvious is prop efficiency and more water drag at the higher true speed for lift off.
 

b7gwap

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Zenith 750 STOL drawings permit up to a Lycoming O-320 on the nose. 160 hp, but it’s heavy, so with the floats I don’t know what your useful load or gross weight would look like.
 

davidb

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Zenith 750 STOL drawings permit up to a Lycoming O-320 on the nose. 160 hp, but it’s heavy, so with the floats I don’t know what your useful load or gross weight would look like.
But, that O-320 will only produce 115hp at 8000 feet. A Rotax 914 is a lot lighter for about the same hp at altitude.
 

rsrguy3

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Oh sure, the zenith will do it but you'll get thrown in jail... CA has seriously tight laws on amphib operations. Look into it, I'm pretty sure Sierra lakes are a no go..
You aren't even permitted to carry bear spray while back packing...
 

davidb

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Oh sure, the zenith will do it but you'll get thrown in jail... CA has seriously tight laws on amphib operations. Look into it, I'm pretty sure Sierra lakes are a no go..
You aren't even permitted to carry bear spray while back packing...
There’s several lakes in the Sierras that are seaplane friendly but also a lot of protected areas where anything with an engine is prohibited. Northern California in general is seaplane friendly.
Not sure why anyone would need bear spray since there are no grizzlies in CA.
 

b7gwap

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edited, realized you were talking about forced induction compensating for pressure loss at altitude. Yes, turbos will do that. Price, complexity, core value all come to mind. But if it’s in the budget, by all means.
 

Pilot-34

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There’s several lakes in the Sierras that are seaplane friendly but also a lot of protected areas where anything with an engine is prohibited. Northern California in general is seaplane friendly.
Not sure why anyone would need bear spray since there are no grizzlies in CA.
Why do people do this? Rsrguy3 never said a word about grizzlies!
 

davidb

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From that list I only see two credible threats; mountain lions and people carrying bear spray. Not sure if bear spray is a good defense for either. Not California, but I seem to recall Yellowstone requires back country hikers carry bear spray for grizzly bears.

We are drifting far off topic. I wonder if the OP has read any of this thread since the first post?

@The Toad, do you have any further questions?
 

wktaylor

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My dad taught me the 3 [4] hells of aviation: High-Hot-Humid-[Heavy].

Water-vapor/spray off the lake will reduce engine/prop performance.

Floats/hulls tend to carry extra weight by water infiltration/condensation.

Water-drag will make getting onto the 'step' tricky in such short distances without massive acceleration.

Approach and departure end obstacles [trees, boulders, abrupt-shorelines and sharply rising surrounding terrain] tend to be prevalent with mountain lakes.

Also, these lakes would rarely/never have be accessed by any other fixed-wing float/seaplane pilots... at least on a routine basis... You would likely be going where no other aviator would have [dared] gone before.

This operational scenario seems like a classic set-up for an accident without exactly the right equipment that is highly reliable.
 
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Victor Bravo

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There is clearly a higher than "normal" level of risk in what the OP wants to accomplish. But this can equally be seen as the OP has simply defined a unique mission statement for what he wants an airplane for.

But the mission statements for helicopters (pinnacle approaches to drop heavy A/C units on top of skyscrapers) and fire bombers (scoop up tons of water at 100 knots without crashing, then fly right into a fire), and aerobatic airplanes (pull and push 6G repeatedly until the pilot's eyeballs burst, then do it again the next day without damaging the airplane)... are also pretty friggin' extreme.

He needs massive acceleration as mentioned, he needs a very high lift coefficient on demand, and he needs floats that get on the step as fast as possible. All of those things are fairly do-able. He did not say he also wanted it to go 200 knots, or use less than 2 gallons an hour, and h did not put a maximum cost on it.

FWIW my opinion is that if he had an airplane that more or less duplicated Steve Henry's Yamaha SuperSTOL, and had floats designed or optimized for rapid transition, he could get in and out of small lakes that most floatplanes could not use.
 
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