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AP Kwak - the Mighty Mini Foam Board Mod of the Jupiter Duck

Gazoo

Well-known member
#41
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All Minwaxed up and drying. Covering the air frame in Minwax brought it from 180g to 190g. I will re-weigh it when it dries thoroughly.

I'll be painting it I suppose. Not sure what scheme. I don't think that acrylic paint will hold up to water. I have an airbrush (cheap one) so I am open to options for paint type. Can anyone offer advice on this? I know you mentioned Plasti-Dip but I wonder if it will stick to the Minwax. Is it heavy? Will an enamel paint be better or worse?

Well, whatever...foam board does not last forever anyway.
 

rockyboy

Skill Collector
Mentor
#42
I'd probably try a light spray of acrylic and then light spray of water based polyurethane to seal it - that worked ok for a foamy I had dew protection, but not sure about full on pond flying.
 

Gazoo

Well-known member
#43
I'd probably try a light spray of acrylic and then light spray of water based polyurethane to seal it - that worked ok for a foamy I had dew protection, but not sure about full on pond flying.
OK. Great! Thanks. I have sprayed the acrylic through the brush before but never polyurethane. I cut the Acrylic with denatured alcohol. Not sure if that's the best idea but it worked OK. What do you cut poly with to run through the brush? Or, is it just brushed on? I should fire up the "Google Machine" and figure it out.
 

Gazoo

Well-known member
#44
Once again, my fingers are faster than my brain. Minwax is a water based polyurethane. Duh...

I shall brush it on with a manual brush hand operated brushy thingy.
 

Gazoo

Well-known member
#45
The Kwak is complete but it seems like it is really heavy. Probably all of the extra glue needed to waterproof it. Like I said, I sealed all of the seams by smearing a layer of glue on. The decals don't help either. It comes in at a whopping 290g without a battery.

Then, with the 850 3S all of the way forward I can't meet the CG. I have to add another 2S battery in the hold to balance it out right. That gives me an AUW of 410g. That's about 100g heavier than recommended.

So...do you think it will fly? Either way, I'm going to give it a shot. What's the worst that can happen?

I think this sea bird looks pretty sweet in US Coast Guard garb. I skipped the paint and went with tape instead. The windows and logos are printed, sprayed with adhesive and taped over with clear packing tape.

Next one will have to be with WRFB from FliteTest. bet I'll save a bunch of weight.
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#46
So...do you think it will fly? Either way, I'm going to give it a shot. What's the worst that can happen?
"What's the worst that could happen?" was my running joke when I used to go skydiving.

I wish I could help with your question, but I have no idea. The plane looks fantastic, though.
 
#47
Gazoo, that are awesome decals - i should create a sticker sheet of them! :applause:

You don´ t need the additional 2s battery (dead weight) for the CG! You should cut the power pod nacelle on the front edge of the wing and glue a longer part on it. Then the ESC and the brushless Motor add more weight to the front. The extended Power Pod Nacelle is available at AP Kwak Downloads. I created it for the divided windshield.

By the way: what is is the weight of one sheet of your white foamboard?
The weight of one sheet FT Waterresistant Foam Board is 115 g.
 

Gazoo

Well-known member
#48
Gazoo, that are awesome decals - i should create a sticker sheet of them! :applause:

You don´ t need the additional 2s battery (dead weight) for the CG! You should cut the power pod nacelle on the front edge of the wing and glue a longer part on it. Then the ESC and the brushless Motor add more weight to the front. The extended Power Pod Nacelle is available at AP Kwak Downloads. I created it for the divided windshield.

By the way: what is is the weight of one sheet of your white foamboard?
The weight of one sheet FT Waterresistant Foam Board is 115 g.
The weight of a sheet of Ross foam board is 128 g. According to my kitchen scale. I have never tried to calibrate so I am not sure of the accuracy. AUW is 369 g at this point so it is a little more acceptable.

This is how much I had to extend out the motor to get it to balance. The ESC is glued right behind the motor.


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I'll have to extend out the battery leads to connect to the battery. I'll try to get some video of the maiden. I'm sure it will be successful...or tragic. Either one sounds like fun to me. Thanks for the help.
 

Gazoo

Well-known member
#50
I was able to get out and hand launch the Kwak. I was too afraid to fly it off of water for fear that I'd never see it again.

Being so heavy and the motor out on the end of the boom, it flew but it was a bit clunky. I'm thinking that I should redo it with the brown water resistant stuff. Gotta say, it looks pretty cool in the air. The wind was also pushing it around a lot. There was a kite in the air too. I totally won the dog fight...
 
#51
Maidened my Kwak today, 342 g AUW (inc 1000mah 3s) , she flew nicely. Not a lot of power , using a DYS 1806 off of my retired Tiny Trainer. Looking forward to flying it at the lake! I like it! It's quirky and cool!
 
#53
Hoping for a water maiden this week

I did a couple of water taxi tests , first in the swimming pool and then in a small pond (unfortunately not a great place to actually take off). It doesn't appear to have any adverse characteristics, it tracked nicely right up to where it started to lift off and I lowered the throttle to let is settle back down. Planning on taking it to a lake later this week. Working on the paint job today!. Update: here is a picture after painting. 2017-07-23 21.05.10.jpg 2017-07-23 21.05.10.jpg
 
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#54
Water maiden!

Had a chance to fly at a small lake this evening, everything went pretty well. The first take-off resulted in some extended taxiing around in the water and I must need to seal the seams a little better, as I had some water in the hull. The second 2 flights went better. It's a lot of fun, looking forward to more flights with the Kwak!
 

varg

Build cheap, crash cheap
#56
Has anyone tried this with the RS2205/2300kv yet? My mini power pod features this little powerhouse and I could use a seaplane.
 
#57
I think the setup with an Emax RS2205 2300KV brushless motor is too heavy for this small seaplane. This setup - especially the engine power - sounds interesting and would be a blast for a larger version of this seaplane. You should scale the plans up!
 
#58
MY KWAK

Haven't maidened mine yet but I like the looks. 2s on an old style 2300KV bell motor seems to give it about 1:1 thrust/weight. Should go O.K. A really satisfying and fun build! I did a flat wing with ailerons, The cowling is a pill bottle and I went for the sponson style floats from the Drake plans. Indications in the back yard (taxi test) are that it should Rise-off-grass pretty well too. I covered the lower hull in UHMW tape .003" so it glides along pretty well on damp cold grass at least. I was concerned about the downthrust tendency, but the elevator has great authority so It should be O.K. Thinking of doing the KWAK-KWAK next, depending on how this goes, with nacelles under the wing to reduce the high-thrustline issue.



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Also did the Otter earlier last month and it flies just great! Lots of 3D printed parts make this one look pretty sweet too.

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foamtest

Toothpick glider kid
#60
I wish I has more mini powerpods! I have 3 C powerpods and only one A. I might just cannibalize that quad I got a while back that hasn't flown....