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Old Jun 13, 2014, 09:36 PM
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DustBen's Avatar
United States, AL, Gardendale
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50" Neptune 25

Last winter, on a lark, I bought the Neptune 50 from Value Hobby.

http://www.valuehobby.com/neptune25.html

I had never flown off water and wanted something... to begin learning (to fly off water with after 40 years of RC experience on land) with.
The ARF kit was in good to excellent condition.

I used an Emax BL2820/07 for power. It's about the largest diameter motor that will fit inside the nacelle.
Having had tons of experience with the motor, I felt that on 4 cells, it is akin to a .28 glow engine (which I felt should be plenty of power).
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The plane is about the 475th model I have "done". Everything is competent and I am very pleased with it.

The plane hung in the shop until 2 weeks ago. I decided it was time to go find out what water flying was all about, and instantly loved it!
Flying off water is a joy!
The runway goes forever, it's relatively flat, and there's little "traffic" to worry about.

The Neptune is a very good and competent model in the air. It has no ill habits flying.
The issue I have is getting it to "unstick" from the water. The plane zooms across the water at fast speed and then suddenly jumps into the air. The excess speed, combined with "up elevator" makes for an unsightly takeoff.

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I am thinking of adding a 1/4" thick balsa piece (where the white paper is) to make one last gradual and smaller step to reduce the "flat zone" in hopes of getting the plane off the water easier.

I would love feedback about this idea.


I am seeking a resolution to the problem by adding "something" in that huge flat area.
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Old Jun 13, 2014, 10:35 PM
Art Schmitz
United States, TN, Crossville
Joined Jan 2012
392 Posts
The Lanier Mariner series used a step wedge that worked rather well.
My .40 size used 1/4 " trailing edge stock. I used double stick carpet tape to attach them even with step and its chine.
This resulted in about a two inch gap between the two.
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Old Jun 13, 2014, 11:06 PM
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United States, AL, Gardendale
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Quote:
Originally Posted by lindart View Post
The Lanier Mariner series used a step wedge that worked rather well.
My .40 size used 1/4 " trailing edge stock. I used double stick carpet tape to attach them even with step and its chine.
This resulted in about a two inch gap between the two.
Trying to understand...

The 1/4" tapered stock ran along the outer edge of the hull terminating at the step?
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EDIT: Just found a picture of the Mariner.
We're on the same page! Thanks!
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Old Jun 16, 2014, 07:49 PM
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Australia, WA, Madeley
Joined Jul 2011
698 Posts
Would you try some step vents?
Bart has been building them into his latest two models and while I don't think there is a flying example of those designs yet , they are found on full-scale aircraft.

In it's simplest form it would just be a tube that allows air to be drawn from above the water line to the back side of the step to relieve the negative pressure.

There is a goose on this page and his Dornier is in this thread

They may just require less dramatic modifications than installing a wedge and can be easily plugged if they don't have the desired effect.

-Mat-
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Old Jun 17, 2014, 02:49 AM
Art Schmitz
United States, TN, Crossville
Joined Jan 2012
392 Posts
The Grumman Albatross at the Air Force Museum has a well vented step.
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Old Jun 17, 2014, 02:51 AM
Art Schmitz
United States, TN, Crossville
Joined Jan 2012
392 Posts
I tried vent tubes on a Ted Strader 'CORKY' 1/2A design...couldn't tell any difference.
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Old Jun 17, 2014, 10:50 AM
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United States, AL, Gardendale
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Quote:
Originally Posted by Wormboy View Post
Would you try some step vents?
Bart has been building them into his latest two models and while I don't think there is a flying example of those designs yet , they are found on full-scale aircraft.

In it's simplest form it would just be a tube that allows air to be drawn from above the water line to the back side of the step to relieve the negative pressure.

There is a goose on this page and his Dornier is in this thread

They may just require less dramatic modifications than installing a wedge and can be easily plugged if they don't have the desired effect.

-Mat-
I was watching a video about flying boats over the weekend and the step vents were mentioned.

In the meantime, I built a small, last step...
3/8" thick, tapered from a high point along the midline down to 1/16th inch at the lateral edges.
It was 3" wide and 5-1/2" long.

Problem is, I didn't know if it would work well so I didn't stick it on with enough glue and lost it after about 20 take-off/landing cycles.

I knew instantly that it worked, and knew exactly the moment it shucked off.

I can build another and glue it on properly in a 45 minute shop session.
I'm just glad to have figured out a solution.
----------------

Along the idea of the step vents... wondering if small turbulators at the beginning of the step would do what vents do... or would they present too much drag in the water.
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Old Jun 17, 2014, 08:01 PM
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Australia, WA, Madeley
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Quote:
Originally Posted by DustBen View Post
I was watching a video about flying boats over the weekend and the step vents were mentioned.

In the meantime, I built a small, last step...
3/8" thick, tapered from a high point along the midline down to 1/16th inch at the lateral edges.
It was 3" wide and 5-1/2" long.

Problem is, I didn't know if it would work well so I didn't stick it on with enough glue and lost it after about 20 take-off/landing cycles.

I knew instantly that it worked, and knew exactly the moment it shucked off.

I can build another and glue it on properly in a 45 minute shop session.
I'm just glad to have figured out a solution.
----------------

Along the idea of the step vents... wondering if small turbulators at the beginning of the step would do what vents do... or would they present too much drag in the water.
I'm pleased you found a solution, and if it works then don't bother with the vents or turbulators. Don't fix it if it aint broke.

I'd be interested to see a picture of your wedge once you have it glued on to your satisfaction.
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Old Jun 18, 2014, 12:37 AM
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Ahh... Just saw the message above moments after photographing the "step".
I replicated what I built Saturday and lost early Sunday morning.

THIS TIME, I slathered plenty of epoxy across the bottom. I got a good seal and adherence.

I'll go try it tomorrow morning (expecting a good result).

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I have to say... I stole this idea from a picture/print Bart posted concerning his Dornier flying boat.
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Old Jun 27, 2014, 10:53 PM
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Update.
I haven't abandoned this thread.

two land based weekend events and weather have kept me away from water.
I will get some video; promise.
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Old Aug 02, 2014, 01:58 PM
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Granada Hills, Ca USA
Joined Sep 1999
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Any more info to share? Still think the float step mod is a good thing?

Do you think it would be a good idea to recover the fuse with glass cloth and resin or just fly it til the covering comes off? I think there is some type of clear tape that I saw someone use on a bigger Neptune at the last float fly. He said it had held up for a couple of years. Don't remember what type of tape he used, tho.

I'm thinking of buying this plane for windy weather flying. High wing float planes tend to tip over when taxiing crosswind, which is sometimes necessary to get back to the launch point.

John in Kalifornia
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