Can't get off the water with Float Plane
 

I've been flying a .40 Hobico trainer with floats from Horizon hobby. I have several dozen successul flights. It's powered with an os 52.

Sometimes I can't get airborne. Once on step, the plane just zips down the lake at takeoff speed, but I can't break the water even with full up. This doesn't happen everytime.

I have more of a problem when the water is like glass. The longer the take off attempt, the harder it gets. If I get airborne as soon as I get up to speed, I'm all set. The plane has plenty of power.

I've heard that the water can have a suction effect, whereby the water tension holds it to the water? I once heard that you have to give it "down" elevator and then "up" elevator to break this suction? Is this correct? When I have a light headwind, it's not a problem. Again, it's when the water is dead calm, I have more of a problem.

I usually abort the take off and try again. It's also turned sharpley and flipped over on me too on these high speed attempts that get aborted.

Please advise on proper technique

RE: Can't get off the water with Float Plane
 

What angle do you have between the wing and floats? A pic would help to see what you have. Chines on the bottom of the floats will help, aridge along the bottom of the step to break up the water at the step...

RE: Can't get off the water with Float Plane
 

I had the same problem with a Great Planes PT 60. At first I was using a 70 size 4 stroke engine. If I had a glass smooth surface, it was hard breaking away from the water. The plane is a flat bottom wing design so I had plenty of lift. I then switch over to an OS 91 and that did the trick. I just needed a little more speed on the water to get the effect of the flat bottom wing for lift. Also remember, when you have floats on a plane not designed to use floats, you need the extra power for the added weight of the floats.
Larry

RE: Can't get off the water with Float Plane
 

The tyipical modelers solution is to add more power. J-3 Cubs don't add more power. Try adding a strip of balsa about 1/4" wide at the step. Also try lifting one float at a time. CAP floats on a Super Cub fly differently than Edo Floats and lots of times we had to fly one float at a time off the water. With glassy water you may need to step taxi back and forth a couple of times to create some chop to fly from.

Also, when you abort the takeoff, apply full up elevator to slow the taxi. Sounds like you have plenty of power and experience. You just need a couple of old bush techniques.

RE: Can't get off the water with Float Plane
 

Do you have an incidence meter?

If you do, check the wing incidence and the incidence of the top of the float. The wing should be +2 degrees with the top of the float ay zero

RE: Can't get off the water with Float Plane
 

I applied 1/4in wide packing tape strips at 45 degree angles on the bottom of the float. This caused enough turbulance between the float and the smooth water to break the adhesion. It is a cool sight watching a float plane leave smooth water and to see that the last wake is from the rudder only.

rcs

RE: Can't get off the water with Float Plane
 

I had two successful takeoffs today. I kept full up elevator from taxi to takeoff. This kept the floats back on their heels, and the plane lifted off. It also tracked straight in the water. I think I need to increase the angle of attack for the wings. But, as I get better with the controls, I will have more success. Holding more up during taxing allows me more straight tracking, but I can't turn as sharp. I also think having full up until takeoff speed and then letting off a little will help. The floats are probably not mounted the best, and may never be. I'm learning how to better use the elevator to control the angle of attack and getting it to lift off.

Here are some pics. Thanks

RE: Can't get off the water with Float Plane
 

To help get off smooth water taxi in a couple of circles to create small ripples in the water. Then take off and you will be surprised how much easier it is to get off slightly rough water than the smooth, glass-like water.

RE: Can't get off the water with Float Plane
 

You need a couple degrees more incidence between the airplane and the floats so the wings sees more air when you want to rotate and take off....

RE: Can't get off the water with Float Plane
 

I agree

RE: Can't get off the water with Float Plane
 

Evan, Where do you fly? Midland? Where do you float fly? I'm in Monroe. Do you know if the Smith Lake Flyers still fly at the lake? Ever been there?

Jim

RE: Can't get off the water with Float Plane
 

You're missing the obvious problem. You need a bigger pond. When you do a pylon turn around the ficus you still have to clear the projector TV, so you're diving it in on final. :-)
And it still looks like you need 3/8" spacers added to the front strut mounts.

RE: Can't get off the water with Float Plane
 

Huntersville. Float fly at Ramsey Creek park but they just "created" a new rule no float flying after 11 years of permission to do so... I will try to get it on the Parks and Rec board meeting to allow it again but for now I'm not floating... Smith Lake used to be great until a group spun off of the Mount Pleasnar club and created the Smith Lake flyers. They were very picky, no outside visitors, limited membership, etc... They flew occasionally off the lake being mostly land based, everytime I go to see them there's no one there, I think they have died out, but I'm not sure. It was a great place to fly.

RE: Can't get off the water with Float Plane
 

I flew at Smith Lake once a couple years ago and there was a problem with the fishermen and other visitors so they had to limit to one or the other. I understand that they still fly there but only on certain days of the month. They are at the regular field around the corner the rest of the time. I fly at Monroe and we just relocated our field to a full scale grass strip and looks like we will get to stay there. I understand Midland (Charlotte's field) might lose theirs when the lease is up in a couple of years. It's getting bad around here. I may have to join Oakboro as it should be some time before the developement gets out there.

RE: Can't get off the water with Float Plane
 

I had similar problems with an LT-25 on floats. Solved the problem by going to dual aileron servos and gaining the ability to use a small amount of down flaperon to help break free of the float suction.

RE: Can't get off the water with Float Plane
 

Hello , Flying float planes myself, It looks like your problem may lay in the position of the step on the bottom of your floats, This " Step " MUST be positioned on the aircraft's balance point, That is without the floats being mounted,
In other words, position the step where the plans say to balance your plane as if it had Wheels , then mount your floats, Then reblance plane if necessary,

Try this , It should cure it's not wanting to leave the water,

RE: Can't get off the water with Float Plane
 

Don't forget to make sure your step is at or behind the CG. That can cause as many problems as the incidence in most cases, although incidence is important as well.

RE: Can't get off the water with Float Plane
 

The step position is critical
Looks like the step is too far back,
IMO the floats need to move forward to allow the plan to rotate,

The float after-body angle needs to be at a right angle to the CG to allow it to rotate easily
The after-body is the part of the float from the step back.
so setting the step right on the CG is too far forward and just saying it needs to be behind the CG is not 100% accurate either.

RE: Can't get off the water with Float Plane
 

I've looked again and I am not seeing a misplaced step. I AM seeing that he could use a little more incidence. And judging by his description of a full-up takeoff run, that seems confirmed. Dragging the heel of the float for the full takeoff run makes for a loooong (if ever) takeoff. Caveat: Too much incidence will cause instability at high speed.

Like I said before, I'd try a 3/8" spacer between the front struts and the floats. Maybe only 1/4".

RE: Can't get off the water with Float Plane
 

Jim, that sure wouldn't hurt to try
Could be the long nose of that plane throwing me off, hard to tell with it sitting in the spa
A side view out of the water would help

It does look like he has a little wedge effect going on there
You always want Zero to a little positive wing to float incidence, ya never want negative or the float will lift the plane instead of the wing. That can make for a wild ride

Something else to consider is he has a semi symmetrical wing on that plane, it's going to take a lot more rotation angle and or speed to get that bird to lift,,
I'm thinking it's a rotation issue

RE: Can't get off the water with Float Plane
 

add the spacer and if that doesn't work maybe you are a little under powered for your weight and you need to try the technique mentioned above.. that is if you have some experience bc you can mess up quickly if you over do it but like it was mentioned above lift one wing then the other, thats what the big guys do when they are underpowered on a glassy surface!

RE: Can't get off the water with Float Plane
 

Hey moderators! You should pass it on to the appropriate "how to" people to do a "how to" on float installations. Sounds like a job for.......SUPER MIKE!

RE: Can't get off the water with Float Plane
 

If people look through their old issues of MAN, there was a great (3 issue I think) "How-to" series on float design and set up.
I used several of their recommendations in my set ups over the years with great results.
I had saved those issues, but when we moved a couple years ago they were lost.
Anyone wants to look back I think it was around '97-'98 when the articles were published, very good info

RE: Can't get off the water with Float Plane
 

I would be interested in any links to how to's. I have flown a long time and heve no clue how to properly attatch my floats

RE: Can't get off the water with Float Plane
 

In my opinion, water like glass = zero wind speed. This is why it takes more power to lift it off water imo.

Beside all the other suggestions, a bigger engine will take care of this issue.

I use a four stroke OS 70 engine on a hangar 9 piper (the 80" wingspan version) and it takes it off in less than 10 meters during glassy water conditions.