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foamboard Dornier Libelle simple seaplane

#81
Wings and fuselage are together. I need to work on the tail and servo mounts next. I'm hoping the blue foam won't be floppier than foam board. Sadly, I don't think the paper/wood glue combo on the bottom of the fuselage worked well. After doing some test runs on scrap pieces of foam, I think masking tape and acrylic varnish will be my method of toughening the belly of the fuselage. Pictures tomorrow, the ones I have so far are poor.
 

Brett_N

Active member
#82
LOL - wings and fuze are togethor for me as well. But my fuze...yeah, I used the top on the bottom and vice-versa. Wondered why it fit so well! No big deal just had to make a few spare pieces to make it all work (it actually worked well, I have a nice big opening on the BOTTOM to work on the electronics :)

I printed a couple copies of the plans so I'll build another one - correctly.
 

Brett_N

Active member
#83
It will be fun to see how different each plane looks LOL. I just realized that my stubby wings I build the wrong direction - so they're long and narrow :ROFLMAO::ROFLMAO::ROFLMAO:

And I think my wing mount is flipped around....and I built the motor mount as the actual power pod....and....oh who knows it's all the same basic shape
 
#85
Dr. LL, are you putting the battery up front or more in the center of the fuselage? I'm going to try to finish up the Libelle today. Since I'm using a power pod from the SE-5 I needed to solder up some extension wires from the power pod to the ESC that I'm putting inside the fuselage with the receiver. I'm trying to decide whether to cut open the bulkhead that I put in the fuselage right at the step. If the battery doesn't have to go behind the step for balance then I'll leave it intact.
 
#86
Well, it's done. It should balance with a 3S 850maH battery. If the wind isn't gusting I'll maiden it tomorrow. Here's the final plane. As I said, it's blue foam, mainly because I have a whole bunch of it still in the storage room. I put a 7x6 prop on it, so hopefully that will be enough with the 1400Kv motor (I just don't have another 8x4.5 slow fly prop just now).
 

Attachments

#88
Synjin - for some more "structure" on the bottom - try a 2-litre soda bottle. trim it into pieces and use tape over it.

Mostly finished with the guinea pig test build. Have a lot of incidence on the motor mount but should still fly fine. These old fogey style wings are really forgiving.

It looks good so far, just need to finish the belly pan but all the electronics are in and working. Add a couple skewers to the tail feathers and we should be good to go. Balances with a 3S 1000 perfectly up in the nose.

Have to travel next week so no building for a while :-(
 

Attachments

#89
Well, here she is on the snow. There's a crust of ice on the snow, as is the case most of the time in late Alaska winter. It flew nicely on a 2S 850maH battery, though I'm beginning to think that the CG is actually forward of the wing crease. I'd started it with the elevator trimmed down and had to give it up elevator while flying. Bringing it down I trimmed it up some. It seems a bit picky about where the trim needs to be set. I flew out the 2S.

It flew better on the 3S battery, and the wind had come up a bit. For some reason, the electronics choked after about 2 minutes of flying on the 3S. I checked the battery when I got home and it seemed fine. Maybe I'd better change to a 20a ESC over the 12a.

Overall, mine is very floaty in the air. It weighs in at only 338g without a battery, and seemed to balance best with the 3S 850maH battery in the nose. I think I'll change out the ESC and try it with a 3S 2200maH tomorrow.

Can't wait to try it on the water...as soon as it's not all frozen. Dr. LL, thanks for the design!
IMG_2957.jpg
 

Arcfyre

Well-known member
#90
@Dr. Looping Looie I'm back home now so I finally got started on this. Still need to hook up the electronics and run the servo and battery extension. Love the look of this bird, can't wait to see how she handles the lake!
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Ok, shes ready for a coat of waterproofing paint. I made a few modifications from the plans:

My battery hatch is hinged at the front so that airflow will keep it closed instead of trying to force it open.

The engine nacelle was enlarged to accept a standard size FT power pod instead of a mini. This gave me enough room in the pod to house the ESC and RX as well. My thought here was to keep the electronics as far from the water as possible.

The enlarged nacelle was covered with a poster board turtle deck, similar to the simple scout and many other airplane designs.

I'm going to slap a coat of paint on tonight and hopefully do some taxi tests on the pond tomorrow.

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#91
@Dr. Looping Looie I'm back home now so I finally got started on this. Still need to hook up the electronics and run the servo and battery extension. Love the look of this bird, can't wait to see how she handles the lake!
View attachment 126525 View attachment 126526 View attachment 126527
Ok, shes ready for a coat of waterproofing paint. I made a few modifications from the plans:

My battery hatch is hinged at the front so that airflow will keep it closed instead of trying to force it open.

The engine nacelle was enlarged to accept a standard size FT power pod instead of a mini. This gave me enough room in the pod to house the ESC and RX as well. My thought here was to keep the electronics as far from the water as possible.

The enlarged nacelle was covered with a poster board turtle deck, similar to the simple scout and many other airplane designs.

I'm going to slap a coat of paint on tonight and hopefully do some taxi tests on the pond tomorrow.

View attachment 126544 View attachment 126543 View attachment 126542
Are you using the Ross foamboard? It’s got that wrinkly, Ross board look to it ;). If it is let me know how it handles water, I’ve heard it works pretty well on water.
 
#93
Yup, it's the Ross stuff. I actually like it because it doesn't compress as easily.
I like that the Ross board is waterproof, but there’s two things I don’t like about it, 1, it’s very flexible and bends easily, 2, the paper is hard to peel off for curves and weight reduction. Also it’s slightly thicker and heavier, but not enough to be a big issue (just barely thicker and a few grams heavier, only an issue on ultralight builds). How do you like working with it? I might just have to try it again and build one of these beautiful Libelles.
 
#94
I flew mine today with a 3S 1300maH battery. It seems like that was almost too much weight. So, getting off the snow was a little hard. Once it was up in the air it did well. The climb rate was a little slow, but it was pretty quick on the level flight. Had to make some repairs tonight because my last landing was a little hard and the motor pod broke loose.

After flying it a couple of times I wonder whether I have the thrust angle too far up. With the reglue of the nacelle I’m not sure I can take it off without destroying the wing to test a different angle. I might move the power pod inside the nacelle and try out a different angle that way. Probably won’t make any big changes until I get to try it out on the water.

My wife, who hasn’t done any hobby things with me for 20 years, went with me this afternoon when I went to fly. I thought she had just been sitting in the car listening to an audiobook, but as I was picking up the plane after the last landing I saw her standing with her phone/camera out. She said she thought it was pretty amazing to watch it fly. That’s pretty high praise from my beautiful girl.
 

Arcfyre

Well-known member
#95
Maiden Flight!

I think I had my battery a little bit too far forward. I had issues getting the airplane on the step during takeoff. What finally helped was dialing in some up elevator trim. At speed, the tail then had enough leverage to lift the nose out of the water. As you can see in the video though, that almost bit me, as the second the plane broke free of the water, it pitched nose up hard. I recovered it, and once I adjusted the trim again, it flew as advertised, very slow and docile.

My landing left something to be desired, again I think I had it set too nose heavy, as the elevator didn't have the authority to flare enough on landing. Luckily there was no damage done, and the plane can be flown again.

I would have flown a second or third time, but the air temperature this morning is well below freezing. This meant that any spray would almost instantly freeze to the fuselage. I had so much ice on the right wing that it actually forced the right sponson under the water. In addition, the elevator froze in place and so I decided to take it inside to thaw before I tried again.

All in all, I think @Dr. Looping Looie hit it out of the park with this design. I plan on flying mine almost exclusively off the water, so I have the battery on the charger and the plane on a heater to melt/thaw for this afternoon. Once in the air it flew extremely well, very responsive on simple 3 channel control. I will move the battery back a little bit in an effort to ease water handling. I think I will also dial in some more elevator travel in my TX. Maybe that will help as well.

 
#96
@Arcfyre looks cool!
I think your fuselage has too much drag in the water. If you havnt already, try to tape it.
Setting the CG a bit back is also a good idea, that way, the step moves a little forward relative to the CG, which is good.
Another thing you could do if it still doesnt work is angeling the fuse up a bit by adjusting the wing so that the front part creates more lift in the water.

Good luck with your next flights!
 

Arcfyre

Well-known member
#97
Just flew it again! All it took was moving the battery back a bit. Much much better water handling. It doesn't like crosswind taxiing, but I had to manuver around a big piece of ice on the water. A gust of wind pushed it over a bit and the right wingtip dipped under the surface of the water. Luckily it recovered and I was able to take off normally.
 
#99
Hola! to all the people who have built/flown these, what power system are you using (prop,motor,ESC, cell count), and how is power? I'm looking at scaling this up for a bigger motor, but would hate to overscale.
 

Arcfyre

Well-known member
2205-2300kv motor
6x5 wooden prop
40A ESC (didn't have any smaller ones)
2x 3.7g servos
1000 mAh 3S LiPo

Max power was 240 watts @ 24 amps according to my watt meter. Actual cruise flight was at 20-25% throttle with about 80 watts and 8 amps. Once it's off the water it's so light it needs barely any power to fly.