Cub Float Technique

I would like to hear from some of the "float" guys, to maybe run through your take off techniques, trim position, flaps, etc.. I've been out trying to improve my technique to get off the water sooner and would like some input. What works the best for you? Crash

On my stock wing 1957 150hp edo 2000 I start with one notch flap, full power, pump stick until come up on step, retrim, find the "sweet spot", at 30 indicated roll right float slightly out of water, about 40 indicated pull on another notch of flaps ( I have the three notch handle) fly her off, level off till 65 and climb out. Just the way I do it, I'm sure others will disagree. Works for me
Rock

Hold the stick all the way to the rear stop, smoothly apply full power. No, I said hold the stick ALL the way back. Hold it there till the nose stops rising. Don't worry about a second rise, or other subtle nuances, just wait till the nose goes no higher.

Now, start pushing the nose over with forward stick. No pumping. All that does is create drag, but it may make you feel more participatory. Push till you feel the fronts of the floats dragging, then back off just a hair.

Once the airplane is cleanly up on the step, push forward gently, to find the front end of the sweet spot. When you get there, you'll feel a slight snubbing tendency as the front of the floats create a bit of drag.

Come just slightly back from there, and the airplane will most likely fly right out of the water, with no rolling, yanking, pulling or sweating.

You can roll up on one float, but in a Cub it really won't get you underway much if any quicker, and if not done right, it creates a LOT of drag. Stick that aileron out there, and you are creating drag, remember.

You can pull on an extra notch of flaps (I use the first notch on a stock cub) if it makes you happy, but that too takes a lot of finesse, and if botched just a tad, it'll lenghten your takeoff run considerably. If you do this technique, remember that you're moving your head as you reach for flap, and it's easy to bobble the attitude, which will kill all the help you just installed. Precision is the key, IF you are going to play this game.

Frankly, with conventional techniques, no messing around, and good finesse, I'll put the basics up against any of the "tricks", and about half or better of the time, the basics work better.

Get the airplane on the step, and push a bit forward. Just when you feel the floats start to snub, gently pull back. No big pull, just a VERY subtle pull. The airplane will just launch.

Then, as noted previously, you gots to get the nose over to let the airplane catch it's breath, and off you go.

MTV

When on a small lake, you might also want to fix two decision points along the shore (Forget about judging distance over water: it doesn't work): One, to be on the step; two, to be airborne. Divide the total distance by 2, 3, or 4 (whatever works for you), and decide in advance where you will chop the power if thing are not going well. As a very rough rule of thumb, you want to be airborn in no more than half the available distance if there are no major obstacles at the far end. Your experince with your airplane (as always) and your judgement of distance can go a long way in preventing bad things from happening.

My personal preference is to set the flaps, retract the w/rudders when within 90 degrees of T/O heading, and open the throttle to be at full RPM by the time I'm lined up. From there, I just fly the airplane without any fancy hand/foot work. Raising one float might be needed in a crosswind. Zig-zag taxi downwind to break up glassy water. I leave the flaps alone while in a turn and until clear of obstacles.

A few more points to ponder: With the trim near center, if you get on the step quick but have to hold a lot of forward stick to stay there, your CofG is probably close to (or beyond) the aft limit. (Did you really remove the covers and visually check the aft float compartments for water?)

A high mountain in front of you seems intimidating, even though it might be 30 miles away: it makes your T/O distance look much shorter than it is. Conversely, a pond in the middle of a marsh looks bigger than it is if you stare at the horizon.

Taking off with a strong river current will get you in the air before you know it. The reverse is also true; you'll be plowing water forever if you try to take off against the current. Consider T/O downwind.

Taking off toward a waterfall can be exiting in two ways. One, the view over the fall is breath-taking. Two, the rising spray might make your engine cough enough to get your attention.

Taking off (and landing) with the door open can be the difference between surviving a mishap and drowning.

Have fun,
Nick

On my heavy 180 hp Amphib I apply full power with half flaps and stick full back. Wait till nose stops rising then release the back pressure to neutral to get on step. At 40mph indicated I pull full flaps and pop off the water.
Have not been able to break the 15 second time it takes from applying full power to lift off. Curious if anyone else has timed their runs.

Take offs

A lot of good points being brought up on this topic.

The reason I asked the question was, I was instructed to always hold the stick all the way back then push the nose over the top to get on step like Mike said. The other night I was out screwing around working on my take offs and step taxing technique. The plane has always felt like I was fighting it during the transition from stand still to on step. For the heck of it I tried no flaps, normal trim and didn't touch the stick. I just shoved the throttle forward and worked the rudder pedals to counter the torque. The plane rolled back then climbed on step and accelerated to lift off speed faster then it ever had. At around 40 mph I pulled on one notch of flaps at the same time pulling gently back on the stick and It was off.

I couldn't believe how smooth it went, so I did it a few more times. This seemed kind of odd and wondered if anyone else has tried it.

It would be interesting to get some take off times from several of us to compare. This would be from the time the throttle goes forward, until the floats break from the water. Take care! Crash

For Aviator,

I don't buy the up current/down current arguements. Try taking off pointed upstream in a fast current (I'm talking 8 to 10 knots, now). Pay attention to where (geographically) you start the takeoff run, and where you get airborne. With many aircraft, including many Cubs, you'll actually use less DISTANCE by taking off upstream, in a no wind condition.

My 170 is about a toss up in that regard. It will get airborne at fairly light weights in about the same distance going up or down stream, but when it's heavy, downstream is better.

It pays to go experiment with your airplane in the real world on this. With many aircraft, you'll find that the upstream option works well.

Remember, it makes no difference whatsoever how many seconds it takes to get airborne in a river (or anywhere else for that matter). What really counts is how much distance you covered during the takeoff. Unfortunately, that's harder to measure.

The problem with landing or takeoffs downstream is that if you hit anything, you'll hit it really hard, and do a lot of damage. The rivers I work in are all glacial, and you can't see anything, so hitting things is a very real possibility.

MTV

Crash,
Will try that technique and let you know how it works for me. I assume that you left the stick neutral and not pulled back for the start of the run.
What about spray to the prop.
My timed runs in my lake have always equaled distance. I have a marker in my 2000 ft. lake and my 15 second runs have always put me lifting off at the same marker.
Mike

Up stream / Down stream

I also don't buy into the argument to always take off down stream. I ran air and jet boats all over the state and they would always get on step faster going up stream. Yes, the "air speed"of the wings going down stream at river current speed will creat lift, but first you need to get those two "boats" mounted to the fuselage on top ot the water, lift alone will not do it. The speed of the current going against the floats (going up stream) will help them get on step and allow you to gain flying speed. I think it is about a toss up. Take care. Crash

Greg,

When I bought my Baumann's from Bud in '95 he recommended the technique you experimented with - Don't touch the stick, let it come up on the step by itself. I often did this (or sometimes put the stick back for only a second or two) - but also couldn't help myself and modified the takeoff by lifting one float once on the step. It got so that after the summer on floats I kept lifting a wheel on takeoff for the first month or so back on tires.

Mike - Baumann's don't have as much of a spray issue as do your Wips. They even leave off any type of spray rail and the fluted bottoms really make them shine. I often fly a Husky on Wips and with the spray rails the prop stays pretty dry but I don't leave the stick nuetral like I did with Baumann's and instead suck it in the gut when adding power from idle taxi.

Brad

Baumann's

Heck, I thought I'd discovered something new. I came home pretty jazzed at how well it worked just leaving the stick neutral. Bud is old school and probably tried this before I was born. Crash

This is a bit like the wheel/full stall/one wheel discussion.

Practice all the techniques. The conditions of weight, water, wind and length will determiine what is best for each particular lift off.

I'm a hands off (except to make sure the tips are up) guy with one notch of flaps for everything easy. Glassy seems to like the right float up technique and rough likes to see the second notch pulled when you hit the top of a crest.

I also like the one float up - make it the outside one please- technique on turning take offs.

The fellow that sold me this cub had flown it from '63 to '98 and advised that you don't need to pull back, but push a bit down on the second rise. His advice was good. The fellow that checked me out said to always use one notch unless you needed more or less. His advice was good.

All advice is good. Practice makes it better.

Keep your tips up.

Gary Reeves

Mike,

My comments re: timing takeoffs vs distance relate to rivers, or other moving water bodies.

MTV

http://www.borntoperform.com/promo_movies.htm

Watch the one titled "Dr. Macy". From throttle to flight is between 6 and 7 seconds.

SB

I see the price went up on the exhaust. Nice takeoff. Anybody know the wind and temp at the time of filming?

You can look at the lake and guess the wind. I think how you climb immediately after lift is very important (ie. how quick would you clear an obstacle).

MTV, Crash,

I admit weight and current speed have a lot to do with it. So here's a simple test: Load up to max gross. Try to T/O with a 10K tailwind (no current) and see what happens. When you're going at 10K over the water, your airspeed is zero. This is the same as standing still (relative the shore and the air) against a 10K current, no wind. Granted, if you do get on the step against a current, you won't cover much distance. The problem is that you might not get on the step at all.

I admit I'm not versed in aero/hydrodynamics (maybe someone here can enlighten me), so I won't speculate on the thrust (developped by a prop at very low forward speed) needed to climb on top of the water at a certain weight, hull size and design. But it seems safe to say that, all else being equal, there is a limit to the weight a given amount of thrust can lift out of the water (and onto the step). If that limit is exceded, then the wings have to lift the excess. And going downstream at 10K can make all the difference.

I do appreciate your comments, though. Would be nice to see tested max tailwind numbers for SC floatplane operations.

Nick

Opinion only, but from the view of a boat driver, (rivers and salt), and float pilot:

The FAA says to go downstream with a tailwind. They have not tried this on a narrow fast current creek with lots of trees. If they had, they would have taxied upstream, turned around while opening throttle and had the current grab the water rudders and push them sideways, wind on the tail that just went sideways, and found themselves filling out reams of paperwork explaining how proper the tecnique was so it was NOT THIER FAULT! (my friends experience explained after repairing both bows).

That being said, take a loaded airboat, (same type thrust) and point it down stream and try to get it up in deep water. Now turn it around and try it.

The fact is that when at slow speed, the float hull is your lift, NOT YOUR WING. Yes, the wing gives some, but hang in there. Just like a power boat, you lift the front of the boat and climb out of the water with power until there is more thrust than drag, the front of the boat comes down and the boat is on step. If you have too much forward weight, the nose digs, too much aft, and you can not get her going.

How many of us have had the ten horse on the boat and our buddies all crouched in the back to get the bow up, then they go back foreward to bring the boat down, once down you pick up speed and are planing???

Same principal with floats. And I will tell you that my planes always gained speed faster on step than in displacement.

BUT, by taking off upstream, I always had control of where I was pointed durring the run.

With the cessna 180, a 5 kt tailwind would cost me about 25% extra time on water, the Beaver did not make much difference. with a cub, (did I ever fly it light) I can recall not liking tailwinds at all because it just plowed too much.

I run a 14 foot airboat with an o-320. she weighs more than the cub, by a bunch, and will haul three people and stay on step in deep water at about 15 mph, slower if going upstream. If I go shallow, I can go at walking speed with two guys and a moose!

So the moral is: look for shallow water for quick takeoffs!

Good comments all, and all worth considering. Aviator, note my admonition that at higher weights, and with different aircraft types, the upstream/downstream results will vary significantly.

Wind over the wing at slow speeds does not equate to an equivalent speed of water past the floats.

That said, try to get a heavily loaded Cessna 206 airborne going upstream with no wind in a big current. May not happen till you burn off enough fuel to lighten it up.

But with MOST Cubs, upstream should frequently be a viable option.

That said, I'll reiterate once more that your results may vary, so go out with YOUR airplane, with various loads (measure them) and try different procedures. The results are the best advice you'll get.

And, it's fun as well.

MTV

Not being a xpert on the subject I'll just add my two cents and then shut up.
Finding the sweet spot became easy for me after an ole geezer showed me that there are two rises of the nose when you add full power. Right between the two rises is the sweet spot and you just have to be patience. So as I add power I wait for the first rise in the nose when it starts over the top I let it go just a few degrees and then hold the stick firm. Bingo the sweet spot. After a few seconds I lift the left float and as soon as the float breaks the water I lift the right float and I should be flying. Best time here at 4500 ft elev is 21 seconds.
(150 hp stock cub w/ first notch of flaps)
As far as landing and takeoff going up stream or down stream I prefer using the stream flow for added speed and less drag on the airframe. If you have ever landed going up stream you'll notice the added load on the floats and how quick you decelerate. I too have a jet boat and do alot of river running but it is not the same as a float plane because of the wings and the transfer of the load from a boat structure to the wings.

Jerry,

Sometimes it's good to stop quick, as long as it's under control, especially in rivers, where there are a million things to hit, all of which will cause a lot of damage.

Your description of the "two rises" sorta lost me, but I'm without my gps right now, and in any case, I've adopted the notion that being lost occasionally isn't all that bad.

As to rolling the left float out of the water first: why wouldn't you roll the right float out first? This uses torque, p-factor and gyroscopic precession all to help you pry that float out of the water. Rolling to the right, you are fighting all those forces. Then again, frankly, most folks, with a fine touch, can fly an airplane out of the water just as quickly without rolling one float out, by simply flying the airplane off the water.

Nonetheless, again, go out and give all these things a squirt, and see what works best for you. If you feel that a particular technique works for you, and you're happy, you have reached nirvana.

Well, okay--you're a happy floater,

MTV

MTV If you don't touch the stick when applying power you will notice that the nose comes up then down and then comes up again (slightly) Right between those two rises is my sweet spot. (I hope someone else has noticed this too) As far as lifting the left float instead of the right float it is easier to move the stick to the right because of my big legs and the flap handle on the left.

Jerry,

Good explanations, thanks. I never keep my hand off the stick on takeoffs, due to the possibility (or my paranoia of the possibility of) of prop erosion with these long props, but I may try the hands off deal the next time I fly someone else's Cub.

Due to an old back injury, my left leg is some smaller than my right--apparently a natural adaptation for flying these things.....

Again thanks for the logical responses.

MTV