Originally Posted by orcas flier

Knowing zero about printed planes...would it be wise to squirt a little expanding foam, the sort sold in a spray paint size can, into the floats before final assembly in case of a catastrophic failure?

I did this in 3D printed boat, two issues, the heat from the expansion and hardening from the outside in. Both caused the hull to deform. It was still usable but didn't look as good.
It made the boat so buoyant i had to add weight to get the prop to bite properly.
Weight of the foam was not an issues.


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Found on web search.......

Originally Posted by santanig5

I did this in 3D printed boat, two issues, the heat from the expansion and hardening from the outside in. Both caused the hull to deform. It was still usable but didn't look as good.
It made the boat so buoyant i had to add weight to get the prop to bite properly.
Weight of the foam was not an issues.


Yeah, you're not going to notice the weight at all on a boat. Interesting note about the heat though. I print with PETG, which is better at heat handling than PLA, but it could possibly soften as well. What brand of foam?

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Originally Posted by flyboyken

Found on web search.......

Those are cool, never seen either of them before.

Originally Posted by localfiend

Couldn't resist trying this as is on the ground...

https://youtu.be/kGr_MACkHfE

Works amazing. Grass takeoffs and landings should be easy. I really hope it snows tomorrow.

I'd be tempted to go fly it off the grass today, but family is over for a late thanksgiving.

Perhaps a slight redesign of the floats and the addition of a rear ventral fin might help such as those on full scale stuff? This Cessna 206 has Wipline floats which are some of the best available and and this pic gives you a pretty good look at the design. If you then look at the bottom of the fuselage underneath the rudder, you'll see the added fin.

https://www.wipaire.com/aircraft_pag...06-stationair/

Originally Posted by Zeeb

Perhaps a slight redesign of the floats and the addition of a rear ventral fin might help such as those on full scale stuff? This Cessna 206 has Wipline floats which are some of the best available and and this pic gives you a pretty good look at the design. If you then look at the bottom of the fuselage underneath the rudder, you'll see the added fin.

https://www.wipaire.com/aircraft_pag...06-stationair/

Yeah, those look pretty similar to what I ended up going with. I have an old flyzone beaver, and I used them as a template for more modern looking floats. I may still do a fin, but I'm going to try and fly it like this first, I really don't want to add any more weight.

Been a busy weekend with thanksgiving, then at work for the start of this week, so I've been a bit slow. The redesigned floats are done however.

After trying out a few different combinations, and checking the volume of the floats at the waterline, I've got something that should be workable. Had to go a bit bigger than I would have liked, and the floats are more modern in appearance, but they have the displacement needed with a nice buffer. So, if my math is correct, no more sinking.

If I get more free time, I may still try and see if I can get a workable triple floats arrangement setup, if only to save some more weight.

Here's the bigger floats next to the little ones. Went together ok, but I think I can make them a bit lighter, and stronger where it matters. They'll be getting another revision if they work well in this shape.

Gonna be getting a couple coats of polycrylic tonight, then it'l be ready to fly hopefully tomorrow afternoon at lunch.

Originally Posted by localfiend

Yeah, those look pretty similar to what I ended up going with. I have an old flyzone beaver, and I used them as a template for more modern looking floats. I may still do a fin, but I'm going to try and fly it like this first, I really don't want to add any more weight.

Been a busy weekend with thanksgiving, then at work for the start of this week, so I've been a bit slow. The redesigned floats are done however.

After trying out a few different combinations, and checking the volume of the floats at the waterline, I've got something that should be workable. Had to go a bit bigger than I would have liked, and the floats are more modern in appearance, but they have the displacement needed with a nice buffer. So, if my math is correct, no more sinking.

If I get more free time, I may still try and see if I can get a workable triple floats arrangement setup, if only to save some more weight.

The picture of the first model with a good look at the bottom of the floats, is pretty good. One of the hardest things to do with a full scale if it's light on power or the density altitude is high, is getting the airplane "on the step" so it can take off. Those bends in the bottom of the floats are designed to help do that by helping to break the surface tension between the float and the water as speed builds up.

Originally Posted by Zeeb

The picture of the first model with a good look at the bottom of the floats, is pretty good. One of the hardest things to do with a full scale if it's light on power or the density altitude is high, is getting the airplane "on the step" so it can take off. Those bends in the bottom of the floats are designed to help do that by helping to break the surface tension between the float and the water as speed builds up.

I can get up on step pretty easy. Taking off after that doesn't work so well when you have low rates turned on...


At least it floats nice now. Handling is easy too, could probably set some speed records driving through a water obstacle course.

Kept thinking it was going to take off at any moment...

Water Takeoff Attempt 1 (0 min 31 sec)

Gonna give it another go once the plane dries off some. Had one ESC get a little water on it, so I've blown everything off before I try again. I think it will go a lot better with higher elevator rates. I messed up and had it on the high speed pass setting. If not, I may change the struts and point the nose up a bit more.

Takeoff was successful, and it flew ok with all the added weight. A little more vertical area, lower aileron rates, and CG just a touch further rearward would probably help balance things all out. I landed a bit hard though, which disconnected the floats. My hardpoints did their job I suppose.

Floats Test 2 (2 min 30 sec)

Plane is in good shape, only damage was to the hardpoints. Think I'm gonna keep this one as a belly lander, and stay away from floats until I redo the spars for use with LW-PLA (foaming 3d printing material) or something else lighter. The planes that are the most fun for me, are the ones that fly great, and don't have to be flown perfectly to be successful. The aerodynamics of this plane work out with the added weight of floats, but that weight is not great for structural integrity.

I've got another design I'm working on, this time with no forward sweep, and it actually has a tail. Gonna plan for use with LW-PLA. If I'm satisfied with the print quality of the material, I'll redo the spars for this plane.

Flite Test | Waterproofing Electronics (18 min 20 sec)

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Originally Posted by santanig5

https://youtu.be/s4z8QMgTEA4


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Yeah, got a can of that. Gonna have to actually use it lol.

Did some LW-PLA tests last night. The foaming plastic works quite well. Parts are half the weight compared to PETG. My WCL will drop from 10.11 to 6.88. That's huge.

Originally Posted by localfiend

Takeoff was successful, and it flew ok with all the added weight. A little more vertical area, lower aileron rates, and CG just a touch further rearward would probably help balance things all out. I landed a bit hard though, which disconnected the floats. My hardpoints did their job I suppose.

https://youtu.be/hdAvjq1-RXQ

Plane is in good shape, only damage was to the hardpoints. Think I'm gonna keep this one as a belly lander, and stay away from floats until I redo the spars for use with LW-PLA (foaming 3d printing material) or something else lighter. The planes that are the most fun for me, are the ones that fly great, and don't have to be flown perfectly to be successful. The aerodynamics of this plane work out with the added weight of floats, but that weight is not great for structural integrity.

I've got another design I'm working on, this time with no forward sweep, and it actually has a tail. Gonna plan for use with LW-PLA. If I'm satisfied with the print quality of the material, I'll redo the spars for this plane.

I think that will be an excellent idea. Remember how NASA's experiment with forward swept wings did NOT work out well?

https://www.google.com/search?q=nasa...UyyVBOBSG7d9M:

I had to chuckle at your comment in the video about it turning better using the rudder. As a licensed full scale pilot as well as an RC modeler, it's unbelievably difficult to get someone who's only turned using the ailerons, to ad that third control..... lol

Originally Posted by Zeeb

I think that will be an excellent idea. Remember how NASA's experiment with forward swept wings did NOT work out well?

https://www.google.com/search?q=nasa...UyyVBOBSG7d9M:

I had to chuckle at your comment in the video about it turning better using the rudder. As a licensed full scale pilot as well as an RC modeler, it's unbelievably difficult to get someone who's only turned using the ailerons, to ad that third control..... lol

I'm always thumbing the rudder stick, even when my plane only has ailerons lol.

I was just amazed at how much more responsive to rudder it was after the floats were added.

Prints are coming right along. This thing is gonna be very light. Gonna need to figure out a color scheme for it.

Originally Posted by localfiend

Gonna need to figure out a color scheme for it.

Navy?

Originally Posted by santanig5

Navy?

Possibly. Maybe early or pre-WWII navy.

Could also do Coastguard. Would be easy since it's already white.