SlowBoat foamy seaplane with plans & video - Page 119 - RC Groups
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Apr 02, 2017, 11:40 AM
Registered User
SkyHawke's Avatar
Got two more flights in this morning in the fresh snow.

Since all the flight surfaces have now been repaired with CF rods, there was no damage today.

This plane is a hoot in the snow. Landing is fun, I was hitting jumps off a snow bank at one point.

Doing donuts in the snow by dragging a float is fun too.

It is such a floaty plane.
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Apr 03, 2017, 12:27 AM
Registered User
I maidened mine on snow also 3.5 years ago. You are right, a blast on snow.
The next day, a lady walking her dog couldn't figure out how a skiier went all over a flat soccer field.
Good flying,
Apr 03, 2017, 10:29 PM
Quadcopters are for Donkeys
King of Plane's Avatar
After almost two years now, I am hoping to maiden my Glowboat this year LOL
Heck, day or night wouldn't even matter to me
Apr 04, 2017, 08:21 AM
Registered User
Squall's Avatar
Nice looking Sloboat!
Apr 09, 2017, 03:04 PM
Somewhere in New York
byteman's Avatar
Slow Boat homemade (1 min 33 sec)
My Slow Boat.....Very nice airplane.....
Last edited by byteman; Apr 09, 2017 at 06:11 PM.
Apr 09, 2017, 06:20 PM
Somewhere in New York
byteman's Avatar

Slow boat

Slow Boat - homemade- nice airplane!!!! (2 min 5 sec)

Flying my slow boat Sunday ,08 ,April 2017.
Apr 09, 2017, 06:48 PM
Somewhere in New York
byteman's Avatar

slow boat

Slow Boat - homemade airplane - very goooood!!! (1 min 25 sec)
Apr 09, 2017, 09:44 PM
Retired CAD guy
birdofplay's Avatar
Wait a minute !!!

I've been to NY and you HAVE WATER ...

so Where is the Slow "BOAT" part of this vid ?

;>] ;>} nudge nudge know what I mean }}}}}}}

just kiddin'
Apr 10, 2017, 10:51 PM
Somewhere in New York
byteman's Avatar

Slow Boat

hhahhahahahhahahahhaha...400 yards there is water. River and sea. But I flew on the field where I usually fly. Because I flew my F330 quadcopter and other planes that I have. I like this little Slow Boat...
Apr 15, 2017, 10:43 PM
Registered User
Took my Slow Boat down to Tygum lagoon this morning to do some water taxi tests Ė but in the end the model boat club had to go and rescue it. ☹ Felt quite embarrassed.
This is the first time the plane has been in the water

The initial taxiing seemed OK and got it up riding on the step OK at one point - but then something happened and one wing tip stayed down on the water.
All I could do was go around in circles.
There was so much drag on the partially submerged wing that full opposite rudder had no effect.

I thought initially that the float had filled with water Ė but that turned out not to be the case.

When the guy brought it back to me I could see there was no water in the float or the hull. So was puzzled as to what had happened to cause the wingtip to stay down.

After thinking about if for a while decided to put it back in the water and push one wingtip under water to see what happened.
It did the same as when out on the water before Ė the wingtip stayed down and it took a little force to raise it.

On investigating I found that the area from the float to the next inboard wing rib it was filling with water and acting like an upside down cup full of water being lifted out of the water.
There was no way for air to get in to break the suction which was greater than the buoyancy of the wingtip float.

I will now sheet the underside of the wing in that section so it canít fill with water and it will also act as added buoyancy.

It was an unforseen issue with under-cambering the wing. The original design is a completely flat wing.
Live and learn huh!
Apr 16, 2017, 09:50 AM
Letís eschew obfuscation.
scott swanson's Avatar
Originally Posted by Yachtie04
I will now sheet the underside of the wing in that section so it canít fill with water and it will also act as added buoyancy.
That's probably the best solution but another possibility is to drill some holes in the wing. One 1/4" hole in each panel shouldn't affect the structure or aerodynamics too much, but it could let air in to break your suction. Put the hole in the high point of the panel when the wing is under water.

Even on the flat wing, it can take a few seconds for a submerged wing to pop back up. Lowering the aileron on the submerged side and giving a bit of throttle can help speed this up.

Apr 16, 2017, 06:29 PM
Registered User
Thanks Scott.
Putting a hole in the top side of the wing was one option I considered - but like you, figured the best solution would be to cover the bottom side of that section - so have started doing that.

On the maiden flight last year at my club field it crashed in a low level turn.
I suspect it tip stalled. It cartwheeled in.
I had a bit of down aileron I noticed yesterday and am wondering if that was the cause of the crash?
I have adjusted the aileron back up again - so will see what happens next time I fly it after I finish the under sheeting of the end of the wing.
I have also changed the motor to a higher KV as it did seem a little underpowered on the maiden flight. (Turnigy Park 450 890Kv to 1200Kv)
It got up on the step quickly and easily yesterday and one of the guys in the club said it actually got airborne briefly about half an inch.
Apr 19, 2017, 03:08 PM
Registered User
Originally Posted by Yachtie04
The initial taxiing seemed OK and got it up riding on the step OK at one point - but then something happened and one wing tip stayed down on the water.
What's your AUW?
When sitting on flat, still water, do the floats touch the water?
If yes, clearly not good.
If not, there still needs to be some space between the float and the water to allow for minor rolls and ripples and such.
If the plane doesn't have enough speed to break the stiction, even after getting on step, it won't fly.
Or, yeah, as mentioned, that upside down cup effect could prevent rolling back up, as compared to an non-ribbed wing.
You could remove that first rib. It's not going to affect the airfoil shape that much.
Sheeting the bottom will only add more weight, with little effect other than discouraging the upside down cup effect.
But those are two different issues, the tip staying under water, and not getting off the water when up to speed.
Apr 21, 2017, 04:50 AM
Registered User
All up weight of my Slow Boat including battery is 742 grams
Battery weight is 128 grams
I am using a 1300 mah 3s graphite battery.
The weight of the under-sheeting of the wing (which has now been done) will be neither here nor there. 1.5 mm sheet Depron is very light.
Maybe a gram or two at most, including strips of thin balsa as supports.

The floats are above the water - but I'd have to go and measure it next time I give it a test float to know the actual distance.
However I can give you the difference in height between the underside of the leading edge of the wing at the root and the bottom of the float.
The bottom of the float is 28 mm higher than the wing at the root.

The under-sheeting will more that double the buoyancy of the outer end of the wing - i.e the sheeted area will be somewhat more than volume of the float itself.

Before the wing-tip submerged I had the plane up on the step briefly at about 3/4 throttle before I shut it down.
Council does not allow planes to be flown there and that is why I didn't continue and take off.

Some movement I did caused the wingtip on one side to get pushed below the surface and the suction held it there because air couldn't get in to break it.
Last edited by Yachtie04; Apr 21, 2017 at 05:38 AM.
Apr 21, 2017, 01:58 PM
Registered User
Originally Posted by Yachtie04
All up weight of my Slow Boat including battery is 742 grams
To double check, is this the stock 39" wingspan? From the pic you posted that looks about right.

If yes, that's DOUBLE the target design weight!!! Not 'some' overwight or even 20-50%. That's the wikipedia definition of 'porker.' It'll fly, but it'll be a Fastboat not a Slowboat. Whatever you see in vids, itl'l need 2x the speed/distance to get off the water.

In %, the added bottom sheet weight is half what it would have been if it were near the design weight. It'll fix the upside down cup effect so that's a plus.

Don't expect it to fly or handle anything like an average Slowboat. I had 9 ppl in my '69 VW Beetle, and it did *NO* handle like a normal Beetle. LOL!!! Actually that was on residential side streets and never got over 10mph because I knew it was seriously dangerous.

Fly it, but I'd seriously recommend pulling out all the hardware and start over. In some of your pics I see what looks like gorilla glue. That stuff sands like glass because it's nearly as heavy as glass. The plane is overbuilt, try again.

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