Mighty mini REDAQ a mini twin seaplane

[Dr. Looping Looie]

My second project for the holidays: This really smart saeplane.
The Redaq 1.8 is not my own design, the original EPP version was designed by Dieter W. and is well known in the german seaplane flyer community, you can find it at almost every event. I want to build a mini foamboard version with FT build techniques and see how it performs. This plane has a few very smart details which make it unique:
It has a double step which produces less drag while cruising over the water and helps to lift the plane out of the water too.
And the pontoons are at the end of the wing and have a step too to allow the plane to drift over the water with differential thrust.
Here are a few pictures of the original:

Tell me if you like the design. Ive seen the original in action, and it really flys great and the water handling is the best i have sen on any plane yet.

 

[jabberwockie]

That looks great. I live near the shore and this would be perfect for me when the tide is in.

 

[foamtest]

I would totally build one if I had two power pack A motors, I have a lake by my house that needs some airplanes in it...

 

[Michael9865]

Love it, it is on my list also, you are saving me a lot of time. I am watching this thread.

 

[Dr. Looping Looie]

After I finished some of my other projects, Im now working on this one. The wing is finished and the fuselage is in progress. The hardest part was defenitly to draw it on the foam and scale all the lenghs up since you cant find good plans or 3-vievs of it.

 

[jabberwockie]

Good stuff, looking forward to it

 

[rockyboy]

Pictures! Need more pictures! :applause:

 

[Dr. Looping Looie]

Pictures! :
Heres the wing. I developed a trick to put the wrap out of the foam board, because this is a seaplane and the pontoons angle to the water is important, I fixed the bottom of the wing straight to the table and added weight and then glued it together. That way the glue keeps it staight.


And here is the main part of the fuse. The nose looks bad because I made it way bigger then needed,that way I can trim it to the right size because I want to make a roundet nose.

And heres the fuse foldet up and with the wing laying on it:

I hope to finish the fuse tomorrow.
Specs: 90 cm wingspan
Two F-packs and 3-S 850 battery.
Thats much bigger than most mini twins, but its an F-pack so the power will be there.
Do you think two 5 gramm servos have enough power to move the ailerons? If yes, I can probably finish it this week, otherwise you must wait until end of april when I buy new 9 gramm servos.

 

[Fluburtur]

I don't think you will have a very long flight time on that, my canadair was eating batteries super fast.

Anyways nice project, don't put it in a tree

 

[rockyboy]

I've used 5 gram servos on this size of stuff before with what I'd guess is about a 75% success rate. Try to keep your connection at the servo end closer to the center of the servo so you're using all the mechanical advantage you can get.

 

[Dr. Looping Looie]

New pictures of pieces:
Step piece:
And bottom piece:

I can hopefully make the nose looking nice today

 

[Dr. Looping Looie]

A problem with designing a plane with a rounded nose is that all the pieces needed look different on the plans then in a 3-view. Because of that i first cut out a piece of the nose from a 3-view which I used to give the bottom piece the right bend, then Im going to cut one side in a curve. I glued it down with just two dots of glue, so that I can remove it, straighten it out and do the other side symmetrical. Then Im going to slowly cut the sides of the nose until they fit inside the other piece.

Did you understand the technique? More pictures of that coming soon.
Here you can see that the wing is flush with the back of the fuse thanks to the curve on the upper tail:

And the fuse is designed so that its hard for the water to get in:

 

[Dr. Looping Looie]

Nose finished:












I think the nose looks just right. Its pretty waterproof, but some water is able to come out. Does a little bit also pass through the paper of the water resistant stuff?

 

[Michael9865]

Here are a couple views that I collected a while back. Not sure where I found them. Hope they help.

View attachment Duck General view.pdf

View attachment Duck Fuse.pdf