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View Full Version : A couple of Newbie pontoon questions.


GreenAce92
07-16-2007, 03:27 AM
Hi,

I was wondering weather or not if pontoons for rc planes are hollow and weighted. If you have pontoon floats for foamies are they usually whole or are they hollow plus are they weighted? Also is everything waterproofed if you have a seaplane?

Thanks.

Gnascher
07-16-2007, 03:36 AM
Hi,

I was wondering weather or not if pontoons for rc planes are hollow and weighted. If you have pontoon floats for foamies are they usually whole or are they hollow plus are they weighted? Also is everything waterproofed if you have a seaplane?

Thanks.

I'm using GWS floats on a Ultrafly Superdecathlon. I suppose you might get different answers from different flyers depending on their own setups, but I can tell you about mine.

The GWS floats are a two-piece construction. The top is foam, the bottom is plastic, and you epoxy these two halves together. There is no additional weighting involved, and they are largely hollow. Some people also cut their own floats out of foam ... these would be solid foam throughout.

As for waterproofing, yes. Water is bad for electronics. I've personally fried an ESC after flooding it. I now seal the open ends of my ESC with hot glue, and my radio is protected by a plastic sandwich bag. It wouldn't stay dry if submerged for long, but will protect the rx in 99% of scenarios I can foresee.

Your motor shouldn't be affected by a dunking, however. Just make sure you run it dry, and then lubricate the bearings.

I've made no efforts to protect my servos, as that'd be too difficult. However, they are positioned within the fuse such that they should stay dry even if the plane ends up getting dunked.

GreenAce92
07-16-2007, 03:47 AM
Hmmm ok what you have said makes sense but is the bottom part the pontoon heavier than on top so that it doesnt act like a sailboat without a keel where it just tips over becuase the tops heavier.

Gnascher
07-16-2007, 03:54 AM
Hmmm ok what you have said makes sense but is the bottom part the pontoon heavier than on top so that it doesnt act like a sailboat without a keel where it just tips over becuase the tops heavier.

A float plane is dealing with very different forces than a sailboat. A sailboat has a heavy keel to keep it upright against the force of the wind on its sails. A float plane is really more like a motor boat. It fact, the GWS float are probably lighter on the bottom than the top, but it doesn't matter.

You're not getting stability on the water from any specific weighting of the floats themselves. The stability comes from the fact that there are two floats spread a distance apart. The top of my plane is way heavier than the floats that support it.

GreenAce92
07-16-2007, 04:08 AM
OH ok so a plane is pretty stable on floats. Does it takes more power to take off of water? I would think so.

Gnascher
07-16-2007, 04:13 AM
OH ok so a plane is pretty stable on floats. Does it takes more power to take off of water? I would think so.

Yes. It takes quite a bit of thrust to get the plane "on step" before takeoff, and then the floats present more drag than conventional landing gear once your in the air.

That said, many planes have enough power in their stock configuration to handle floats without modification and still maintain a satisfactory flight envelope.

One example is the HZ SuperCub. I've seen quite a few people successfully outfit this plane with floats with no modification beyond that which was necessary to physically mount the floats.

GreenAce92
07-16-2007, 04:16 AM
Hmm thanks for the info. Hey i wathced this corney movie once and it had a cessna with floats and they ripped off. Do planes really crash because the pontoons rip off?

Thanks.

Gnascher
07-16-2007, 11:46 AM
If the pontoons ripped off, you would crash.

You should definitely take care to make sure you mount your pontoons securely so that this does not happen under ordinary circumstances.

GreenAce92
07-16-2007, 03:16 PM
Wait in the movie the pontoons were ripped off because a harpoon with a line hit hte pontoons and as the plane flew away the line tightened until SNAP! it ripped the pontoons clear off. But he had like 1000 ft of Alt. though so you would crash then? Why is that because the plane would get off balance or something.

Gnascher
07-16-2007, 03:29 PM
You would still be able to fly if you lost your pontoons in flight, assuming the CG wasn't terribly affected. Landing, however would be a different story.

If all the attachment gear were ripped clean off, you may be able to salvage a belly landing if you could find a suitable area. More than likely, you'll have your struts and such hanging down, making a belly landing a little messy.

You could also put it down in the water with the knowledge that you'll be taking a swim or a paddle to retrieve your floatless (but hopefully still floating) plane.

This is getting silly.

GreenAce92
07-16-2007, 03:54 PM
A friend of mine lost his Pt18 i think its called that but it's basically i think a relative of the Supercub. But i think the story goes a couple of instructors flew his plane and misjudged landing and it all ends up with the plane sinking in a lake because they had missed the airstrip but he was able to retrieve it later. Now he just has a beautiful yellow supercub. But yeah it would kinda suck if you had to belly land with some struts poking out.

Detroit Dave
11-16-2007, 08:27 AM
I was at the Skymasters Regional Float Fly a few years ago and a lady was flying a glow powered plane with floats. Someone didn't tighten the landing gear bolts and at about eighty feet she lost the floats. The floats tumbled into the lake and she kept flying the plane. I'm pretty sure it was a Kadet LT-40. She finally just belly landed the plane in the lake and the rescue boat fished it out and then went after the floats.
It didn't crash. It flew just fine after the floats dropped off.

Dave