Flying boat

Candu · May 23, 2016, 07:49:59 PM

Inspired by Michael's Canadair water bomber and wanting to try out float fly, I decided to put something together quickly to try out before the end of the flying season. Using a combination of blue insulation foam and Dollarama foam board, I think a quick build can be accomplished before the next float fly.

It's still a work in progress but is at a stage now that it's recognizable as a flying boat. Since it was not modelled after any one full size aircraft, there is no plan for the built. I use my normal "cut-to-fit and glue-if-it-does-fit" "design-as-you-build" construction method. It ended up with a 60" wing span, 43" total length, 20" high from bottom to top of vertical stabilizer. Weighing in at 1150g without battery. Here are some pictures.

I have laminated the fuse with 1.7 mil laminate at the bottom and half way up the side to keep water out. The other portion I use a 1.0 mil just to keep the weight down. I still need to work on the nose and cut a v-shaped hull. I'm confident it will fly since it is quite similar to the cargo plane I built over last winter but I'm not sure how it will taxi, take-off, and land on water. Bath tube floating tests (without the wings of course) show that it floats okay but has a tendancy to roll over. I think the outboard wing floats will keep it from rolling over completely. Also, I'm wondering how critical a v-shapped hull is in this application...

Suggestions and tips welcome.

octagon · May 24, 2016, 08:02:36 AM

Good job Frank, man, you work fast! Will not make the next float fly so let me wish you luck on the maiden.

Candu · June 03, 2016, 09:05:28 PM

Thanks Rob. Looks like it will not be ready for the Beeton float fly event. It took longer than expected. Finally sanded a V shape hull and modified the nose. Next would be the wing floats...

Skyking · June 04, 2016, 10:57:38 PM

Hi Frank,
Way to go with your enthusiasm.
I don't see a step on the bottom of the hull.
Is that deliberate?

Kind regards,

Ken

piker · June 05, 2016, 04:22:43 PM

Looks great, Frank. I look forward to seeing it at the float fly's!

Ken... I see a step...

Candu · June 05, 2016, 07:32:21 PM

Actually, I ended up with 2 steps - but not by design though. The first step is about an inch behind the CG and the second step is about 4" behind the first. I can always shave off the 2nd step later if it proves to be a hinder during the take-off run.

Grounded this morning due to rain so a slap on some paint on the fuse...

Candu · June 07, 2016, 06:28:36 PM

Even though the forecast is for shower and high wind, but the the TEMAC morning crew have learned a long time ago that looking out the window is almost always better than the weather forecast. it looked nice out my window this morning so I decided to maiden this flying wing to make sure it flies before I spend more time on it.

On site, it was quite breeze, about 20kph+ from the west. It failed on the first attempt to take off because of lack of power from my 2200 3cell lipo. Jim was kind enough to "rent"

his 4cell 2200 to me for the test. In return, Jim can play with my servo for 10 minutes.

Everyone in the morning crew stopped their flying activities to provide support to my maiden effort.

Here's the video of the short flight:

https://www.youtube.com/watch?v=357J_BnWxqc&feature=youtu.be

Oscar · June 07, 2016, 08:46:27 PM

Great maiden flight. Beautiful landing. I like the colour. Very sharp!!

Skyking · June 07, 2016, 11:49:26 PM

Nice going Frank!

It feels good to have a happy maiden and yours was very sucessful.

Ken

piker · June 08, 2016, 04:41:53 PM

Awesome! Great job, Frank. Congratulations on a fast build and very good test flight!

Candu · June 10, 2016, 04:38:10 PM

Thanks guys! Still have to do the wing floats. I did another bath tub float test to see what is needed. It floats high and displaces less than an inch of water. From what I see, wing floats are a must since the plane will roll over because it is very top heavy. So when the plane is sitting at rest on the water, one of the float will be in contact with the water for sure. The plane will be leaning at an angle. This angle will be a function of the distance between the bottom of the float and the surface of the water.

My question is, what is optimum distance between the bottom of the float and the surface of the water? I tried googling for an answer but so far no luck. I would appreciate some ideas from you guys on this. Thanks.

piker · June 10, 2016, 05:17:40 PM

You want enough so the floats don't drag in the water when powering up and getting on step, but enough to keep the plane fairly level for taxiing and for a straight track while starting the run-up for take-off. Of course, when the plane is "on step" the tip float will be further out of the water, but at that point, they're not needed anymore, so it's good that they're out of the way and not catching.

So... based on all that, and the apparent size of your model, I would aim for approximately 1/2" under each float, while the plane is sitting in the water and level. Also, if you can, leave a system for adjustment after you see how it works in the water. It's not uncommon to fine tune.

Here are a couple of other considerations for tip floats... fairly flat bottom works best as the tip float will skip off the water when it comes in contact, rather than digging in, and a good angle up at the front is also helpful. A little for than "scale' is usually needed at model size. Also make sure you're floats are big enough to provide good buoyancy to resist being submerged from a cross wind. However, with that said, I've found that scale size usually works pretty good. It does on the water bomber.

Candu · June 12, 2016, 09:56:30 PM

Thanks Robert. I following your advise and carved out the flat bottom floats out of blue insulation foam. The floats are covered with 1 mm laminates. I also made it's height adjustable for fine tuning purposes. By removing 2 locking pins, I can raise or lower the floats in 1/2" increments. One last item left to do is the engine cowls...

Candu · June 18, 2016, 09:59:45 PM

Made the float fly this time. Did the maiden on water. My first water flight ever, After two lipos with of flight time, interior remained completely dry. the only place that got wet was the underside of the wing.

https://www.youtube.com/watch?v=e7RLuY0yAkw&feature=youtu.be

(Still can't figure out how to embed Youtube video in the post itself...)

gmcnic · June 18, 2016, 10:12:09 PM

Nicely done and congratulations Frank!

To embed Youtube video's, choose the link after clicking on share.
In your case, the link is "https:// youtu.be / e7RLuY0yAkw". (Spaces added)
When you post, the link will change to the embedded view.

https://youtu.be/e7RLuY0yAkw