New to floats..what is "step of the float"?
05-31-2003, 09:11 PM
#7
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Re: spinner to float location
Originally posted by dan4466
From what I've read, this looks to be about right. Am I correct? Also, I read to change balance of plane by doing the floats and not the plane. What do you do to the floats to change balance?
From what I've read, this looks to be about right. Am I correct? Also, I read to change balance of plane by doing the floats and not the plane. What do you do to the floats to change balance?
1) make your radio battery moveable so you can balance without adding weight. I have to move my 1500mah battery about 2" aft when my Cub is on floats.
2) add weight to the float front or tail (half the weight in one float, half in the other) to get the CG where it needs to be with the floats on. That way when you remove the floats you don't have to remember to move the battery pack around (a preflight checklist helps here)
Don
06-01-2003, 10:14 AM
#8
Senior Member
New to floats..what is "step of the float"?
It looks like you will have to move your floats foreward. The setup should have the step, on the bottom of the float, at the CG of the plane or up 1/2" behind the CG. This will allow the plane to rotate properly on takeoff. Also you should have a couple inches of float ahead of the prop to prevent the nose of the floats from digging in. After mounting in this way, recheck your balance and add weights if necessary. Mr. Jim Casey has a web site for the Florida Float Fliers that contains a lot of info that you should know. Check other threads in this forum on the same subject and you will find his name and the web site........Seaplane
06-01-2003, 10:21 AM
#9
Senior Member
New to floats..what is "step of the float"?
Here is the address for the Florida Float Fliers http://jcasey02.home.gate.net/fff.html. Go to the Articles section......Seaplane
06-01-2003, 10:32 AM
#10
Senior Member
New to floats..what is "step of the float"?
Here is the other web site I was thinking about http://www.flyinglindy.homestead.com...ndfloats.html. It explains how to make floats and skis and how to set them up. Great site..................Seaplane
06-01-2003, 05:32 PM
#12
floats
Seaplane-
If I put the step at the CG, it leaves the tip of the floats flush with spinner tip. Thats the best I can do. If my floats were a couple inches longer, I'd be all set. I forgot to say, I have flaps on this plane that does give alot of lift. Will this help with lift-offs on a floatplane?
Thannks,
Dan
If I put the step at the CG, it leaves the tip of the floats flush with spinner tip. Thats the best I can do. If my floats were a couple inches longer, I'd be all set. I forgot to say, I have flaps on this plane that does give alot of lift. Will this help with lift-offs on a floatplane?
Thannks,
Dan
06-01-2003, 11:09 PM
#13
My Feedback: (551)
New to floats..what is "step of the float"?
Contrary to popular opinion, I've found that moving the floats on a flat bottom trainer forward an inch or more (in front of the CG) improves their take off performance dramaticaly. Particularly if the nose of the floats is a little short to start with.
I attribute this to the effect of the strong downthrust built into these airplanes trying to bury the nose of the floats before flying speed is reached.
Try it as-is if you'd like, but if you notice a tendancy for the front of the floats to dig in, move them forward and try again.
Jim
I attribute this to the effect of the strong downthrust built into these airplanes trying to bury the nose of the floats before flying speed is reached.
Try it as-is if you'd like, but if you notice a tendancy for the front of the floats to dig in, move them forward and try again.
Jim
06-02-2003, 12:47 AM
#14
New to floats..what is "step of the float"?
My son flies a Hanger9 super Stik, and the floats are too short. The nose of the float is about at the prop line. Takeoff runs are long. Flap(eron)s help. Don't droop them too much, just 15 degrees or so. Any more than this and you're asking for (1)a lot of drag (2) bizarre trim right after liftoff
06-04-2003, 03:00 AM
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New to floats..what is "step of the float"?
DON-DON'T FLY IT YET!
The step in a float is on the underside where your float thickens from the aft end towards the forward end. Where your CG of your plane ends up in relation to this, is arbitrary. Casey help this guy out. Fred C - get in here! One of your most important mounting points is not the spinner, but the prop arc. Mount your float tip, 2 to 2 1/2 inches in front (!) of your prop arc. The spread of the floats (on center) should be 25% of the wingspan of your plane. I've seen too many fliers torpedo their planes on take off, and many more tip over because these are not obeyed. Click on my gallery and this will give you some inspiration. The red line on the floats' nose is my prop arc, it's also good to stay away from that area when your engine is running.
Remember also, on take off, don't horse it off the water. Gain speed then apply back pressure. On landing, fly it in, don't chop the throttle as you're about to hit the ripples. You'll have a blast when you're all set up. Good Luck!
Jim Soque
The step in a float is on the underside where your float thickens from the aft end towards the forward end. Where your CG of your plane ends up in relation to this, is arbitrary. Casey help this guy out. Fred C - get in here! One of your most important mounting points is not the spinner, but the prop arc. Mount your float tip, 2 to 2 1/2 inches in front (!) of your prop arc. The spread of the floats (on center) should be 25% of the wingspan of your plane. I've seen too many fliers torpedo their planes on take off, and many more tip over because these are not obeyed. Click on my gallery and this will give you some inspiration. The red line on the floats' nose is my prop arc, it's also good to stay away from that area when your engine is running.
Remember also, on take off, don't horse it off the water. Gain speed then apply back pressure. On landing, fly it in, don't chop the throttle as you're about to hit the ripples. You'll have a blast when you're all set up. Good Luck!
Jim Soque
06-04-2003, 11:07 AM
#17
New to floats..what is "step of the float"?
I tend to look at this situation pragmatically: You already bought the floats-you might a well try to make them work.
They are on the plane in a reasonable approximation of a correct installation. At least, the big end is in front. And they are on a nice, forgiving trainer. The step is placed according to the guidelines, and the balance is on the little dot.
At this point, If it were MY plane I would plop it in the water and see if it works.
Since the nose of the floats is a little short, the prop might get some spray. Always Use a plastic prop for water flying. Taxi and start your takeoff run with full UP elevator to help the prop clear the spray. Taxi around a little to get the feel of it before you try to take off. If the noses of the floats try to submarine when you add power, that's a problem that can be fixed by relocating the floats forward.
You have noticed by now that it is easiest to taxi into the wind. Someday I will write a chapter about this, but there's more to it than just adding bigger water rudders. Full-UP elevator and about 4 clicks of power help make the rudder effective so you can taxi crosswind.
Point it into the wind and try a takeoff:Assuming the floats don't try to dive, as you add power to go faster, the plane will rock back, nose up, as the floats climb over their bow wave, then it will rock forward and be planing on the step.
As soon as the plane pops up on step (shouldn't be more than 2 seconds) relax the elevator and be ready to steer with the rudder (GENTLY). If the plane wants to change direction on its own, double-check the alignment of the floats. If you're taking off in frort of you, you should see that the rear end of the floats is above the water and the plane will sit much like if it was on a table-top. Hold just the slightest breath of back pressure on the elevator and the plane will lift off when it hits flying speed. Don't horse back on the stick and cause the rear of the floats to touch the water.
Landing: Just like a pavement landing: Into the wind, keep the wings level. Crosswind landings are shorter because of the big SPLASH as the plane trips over the float and cartwheels. Fortunately on water you can ALWAYS land into the wind.
Start off by trying the full-stall type of landing you use on pavement. Unlike a hard-surface landing, there is no shadow, except on the vegetation as you come over the bank. That's a good way to know you have cleared the bank and it's OK to drop below the tree-line. On glassy water, watch for the reflection of the plane. When your floats touch the reflection of the floats, you just landed. On ripply water, it's a little harder to judge altitude. If there are white-caps, you should not have taken off and you should look around for a grassy field to land on.
After you get the hang of it, make the landings a little hotter like a "wheel" landing in a taildragger. Set it down very gently on the water and it will be the smoothest landing you ever saw.
They are on the plane in a reasonable approximation of a correct installation. At least, the big end is in front. And they are on a nice, forgiving trainer. The step is placed according to the guidelines, and the balance is on the little dot.
At this point, If it were MY plane I would plop it in the water and see if it works.
Since the nose of the floats is a little short, the prop might get some spray. Always Use a plastic prop for water flying. Taxi and start your takeoff run with full UP elevator to help the prop clear the spray. Taxi around a little to get the feel of it before you try to take off. If the noses of the floats try to submarine when you add power, that's a problem that can be fixed by relocating the floats forward.
You have noticed by now that it is easiest to taxi into the wind. Someday I will write a chapter about this, but there's more to it than just adding bigger water rudders. Full-UP elevator and about 4 clicks of power help make the rudder effective so you can taxi crosswind.
Point it into the wind and try a takeoff:Assuming the floats don't try to dive, as you add power to go faster, the plane will rock back, nose up, as the floats climb over their bow wave, then it will rock forward and be planing on the step.
As soon as the plane pops up on step (shouldn't be more than 2 seconds) relax the elevator and be ready to steer with the rudder (GENTLY). If the plane wants to change direction on its own, double-check the alignment of the floats. If you're taking off in frort of you, you should see that the rear end of the floats is above the water and the plane will sit much like if it was on a table-top. Hold just the slightest breath of back pressure on the elevator and the plane will lift off when it hits flying speed. Don't horse back on the stick and cause the rear of the floats to touch the water.
Landing: Just like a pavement landing: Into the wind, keep the wings level. Crosswind landings are shorter because of the big SPLASH as the plane trips over the float and cartwheels. Fortunately on water you can ALWAYS land into the wind.
Start off by trying the full-stall type of landing you use on pavement. Unlike a hard-surface landing, there is no shadow, except on the vegetation as you come over the bank. That's a good way to know you have cleared the bank and it's OK to drop below the tree-line. On glassy water, watch for the reflection of the plane. When your floats touch the reflection of the floats, you just landed. On ripply water, it's a little harder to judge altitude. If there are white-caps, you should not have taken off and you should look around for a grassy field to land on.
After you get the hang of it, make the landings a little hotter like a "wheel" landing in a taildragger. Set it down very gently on the water and it will be the smoothest landing you ever saw.
06-04-2003, 12:50 PM
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New to floats..what is "step of the float"?
If the noses of the floats try to submarine when you add power, that's a problem that can be fixed by relocating the floats forward.
--Bill
06-04-2003, 02:27 PM
#19
New to floats..what is "step of the float"?
No, don't change the downthrust because of the floats.
Engine downthrust is generally tuned with regard to flight characteristics, not taxiing considerations. The nosing-over experienced with floats, in my experience, either comes from overloaded floats or poor float design. There is almost no drag made by the floats at idle, but as the airplane speeds up, the floats push a bow wave in front of them. This is the maximum drag point. If the float fails to rise over the bow wave, it makes a lot of spray as water hits the prop and the plane could refuse to go fast enough to get on step. If you have ever water skiied, you have felt this as the boat pulls like bloody hell until you pop up on top of the water (on-step). Once you're up, you can one-hand the rope and sometimes it will even go slack. Our airplanes accelerate noticebly once they pop up on step, due to the decresed drag.
I suppose if I put on my Engineer hat and did the equations, having floats instead of wheels hanging below the airplane <might> let me use slightly less downthrust, but in my experience my planes don't seem to fly much differently with floats than without them. Floats have a lot more frontal area than wheels, but have a much lower coefficient of drag, so a big float might not cause any more drag than the wheel it replaced.
Downthrust is used to compensate for (1) having the thrustline below the center of drag, (which is usually the wing) (2) to compensate for trim change as the wing makes more lift at higher power/higher speed settings. My telemaster balloons at high throttle setting whether it has floats or not, and telemasters have a lifting stab to prevent that.
Flying boats such as the Seamaster have the thustline above the wing and not below, so they need UP thust to keep the engine from pushing the nose over as you add power. This was one of the problems with the Herr Aqua-star: the engine pod was on top of a long arm and it got a lot of leverage to push the nose down. Still, that's for flight and not for taxiing. The submarining thing on the Aqua-Star was fixed by adding chine-rails to the sides of the hull to get more lift from the water.
Engine downthrust is generally tuned with regard to flight characteristics, not taxiing considerations. The nosing-over experienced with floats, in my experience, either comes from overloaded floats or poor float design. There is almost no drag made by the floats at idle, but as the airplane speeds up, the floats push a bow wave in front of them. This is the maximum drag point. If the float fails to rise over the bow wave, it makes a lot of spray as water hits the prop and the plane could refuse to go fast enough to get on step. If you have ever water skiied, you have felt this as the boat pulls like bloody hell until you pop up on top of the water (on-step). Once you're up, you can one-hand the rope and sometimes it will even go slack. Our airplanes accelerate noticebly once they pop up on step, due to the decresed drag.
I suppose if I put on my Engineer hat and did the equations, having floats instead of wheels hanging below the airplane <might> let me use slightly less downthrust, but in my experience my planes don't seem to fly much differently with floats than without them. Floats have a lot more frontal area than wheels, but have a much lower coefficient of drag, so a big float might not cause any more drag than the wheel it replaced.
Downthrust is used to compensate for (1) having the thrustline below the center of drag, (which is usually the wing) (2) to compensate for trim change as the wing makes more lift at higher power/higher speed settings. My telemaster balloons at high throttle setting whether it has floats or not, and telemasters have a lifting stab to prevent that.
Flying boats such as the Seamaster have the thustline above the wing and not below, so they need UP thust to keep the engine from pushing the nose over as you add power. This was one of the problems with the Herr Aqua-star: the engine pod was on top of a long arm and it got a lot of leverage to push the nose down. Still, that's for flight and not for taxiing. The submarining thing on the Aqua-Star was fixed by adding chine-rails to the sides of the hull to get more lift from the water.
06-04-2003, 03:23 PM
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New to floats..what is "step of the float"?
I wouldn't think that downthrust would matter with floats, but recent work trimming out a new Lazy Bee made me more attuned to the engine thrust issue. This plane is happiest with 3-4 degrees of downthrust, but with the initial slight upthrust I had on the first flight, the plane would leap off the ground and practically stall when I poured on the throttle on takeoff. I suspect that this problem is unique to the Bee, and possibly with the configuration of my Bee.
I guess the rule of thumb (or thumb-and-forefinger, if you fly that way) should be that if the plane takes off and lands well on land it ought to do well on water.
Good discussion....
--Bill
I guess the rule of thumb (or thumb-and-forefinger, if you fly that way) should be that if the plane takes off and lands well on land it ought to do well on water.
Good discussion....
--Bill
06-04-2003, 10:27 PM
#21
My Feedback: (551)
Down thrust
Many trainer type (flat bottom wing) airplanes have as much as 5 or 6 degrees of downthrust to compensate for the wings tendancy to create higher lift as the speed increases. This downthrust will pull the nose down and cause the airplane to dive momentarily if high throttle is added at low airspeeds.
To verify this, trim the average trainer to fly level at low speed, do a low, slow flyby and then hit the throttle as it passes in front of you. You will see the airplane dive before it picks up enough speed to balance the downthrust with extra lift.
Now when you advance the throttle on these same airplanes on floats, the downthrust will try to push the nose into the water until the wing starts to make enough lift (and the stab starts to make enough negative lift) to bring the airplane back into equilibrium.
Drag is a major factor as well, so don't be surprised if your floats dig in.
Jim
To verify this, trim the average trainer to fly level at low speed, do a low, slow flyby and then hit the throttle as it passes in front of you. You will see the airplane dive before it picks up enough speed to balance the downthrust with extra lift.
Now when you advance the throttle on these same airplanes on floats, the downthrust will try to push the nose into the water until the wing starts to make enough lift (and the stab starts to make enough negative lift) to bring the airplane back into equilibrium.
Drag is a major factor as well, so don't be surprised if your floats dig in.
Jim
06-05-2003, 09:38 PM
#22
floats
"Always Use a plastic prop for water flying"
Didnt put much thought to the type of prop. Nice to know. Haven't finished putting the floats on yet. Will get to it soon. My mother has beautiful 1 1/2 acre pond that is alittle over 400ft long. Smooth as glass. This is what has put an itch in me to give this a try. Thanks again Jim and everyone.
Dan
Didnt put much thought to the type of prop. Nice to know. Haven't finished putting the floats on yet. Will get to it soon. My mother has beautiful 1 1/2 acre pond that is alittle over 400ft long. Smooth as glass. This is what has put an itch in me to give this a try. Thanks again Jim and everyone.
Dan
