Just noticed that my Sea Duck has accumulated over 16 hours of actual flight time. I guess that is quite a lot really for any RC aircraft, especially a sea plane. My Duck has so much time on it because I REALLY enjoy flying it plus I have the luxury of having the perfect little private lake right in my back yard. Many times I have looked outside to notice ideal conditions and just simply grabbed the Sea Duck and plunked it into the lake. Think about it. 16 hours = about 240 battery packs, probably over 1000 landings the way I fly it. At an average of 20 mph, it's traveled well over 300 miles. So, I thought it might be a good thing to pass along little things I have learned from my experience with this very experienced Sea Duck.
Read on and I will share what I've learned in hopes this will help someone else.
The design team really did a great job on this one! I have built most of the Flite Test series and this one for sure is one of the best if not the very best.
Sea planes seem like they are always trying to tip over or flip onto their backs. Not the Sea Duck. The low CG eliminates that problem. Seaplanes also seem to weathervane a lot making them really hard to taxi in anything other than perfectly calm conditions. Not the Sea Duck using the differential thrust option. About the maximum wind I've flown in has been around 15 knots and I have no problem at all with taxi on water.
The Sea Duck also leaps out of the water. In calm winds without really trying it only takes a few feet. I feel like those big props blowing over that fat wing creates a bit of a lift machine on it's own even before you factor in the relative wind from the forward movement of the airplane. Takeoff runs are very short if you want them to be. It is however a lot of fun to go skimming across the lake making making high speed turns. It is really two in one. A great airplane and a great speed boat.
Flying is very conventional. Flys like any trainer with a fat wing. Landing is predictable and the best part. Skimming it onto the surface without a splash is quite gratifying. I generally carry just a touch of power through the landing. Afterwards cutting the motors and watching the little airplane settle into the water becoming a great little boat!
Water Resistant Foam (not so much)
The thing that will probably kill my duck is the not so water resistant brown foam board. I think this material is decently water resistant in it's natural state however, following the instructions for paint preparation, I lightly sanded the material before priming. Well....I think I lightly sanded off most of the waxy coating material in the process. About the only thing that is keeping my duck alive is the Rustoleum paint job. It seems like my airplane gets a little mushy with use. I'm noticing that the wings are even starting to droop a little. If you are going to paint, my suggestion is to go exceptionally lite on the sanding. My suggestion is to do what a friend did and completely cover the project in vinyl. That's a big job but so is painting. Vinyl should give lots of extra life to the airframe and also prevents denting that is common with the brown foamboard.
UPDATE TO THE ORIGIONAL ARTICLE
I've rethought the idea of covering the entire airplane in vinyl. My friends 100 percent vinyl covered Sea Duck has had an issue. The problem relates to hot glue not binding well to vinyl. On most FT airplanes this is not an issue but on the SD many areas need to be sealed from water with hot glue. The vinyl won't allow this very well. What is worse, the glue joints between the wing and the nacells are structural and need to be very strong. My friends airplane nearly lost the outer wing on one side because the glue joint failed at this joint over the vinyl.
This is not to say that vinyl can't be used. I'm currently building a second Sea Duck. It will us a combination of vinyl and paint. That is probably going to be a good combination.
The Bow Section
For sure, if you build a Sea Duck do something to reinforce the bow. It is just a single sheet of foam and nothing else. It is far too weak to stand up to much of anything. After only a hundred landings or so it was clear that I would have to reinforce the most forward under section of the nose. During the build this could easily be done by creating doublers in some fashion as the project is built. In my case I actually cut a bulkhead and made a separate compartment in the nose that I filled with low expanding foam insulation spray. This worked great and now the front of the airplane is super solid. I plan to start construction of my second Sea Duck soon and plan to write another article describing my foam filled nose.
This is the only other really weak part on the airplane. It's not really the hatch but the hinge. I've rebuilt mine a few times but keep in mind, mine has probably been opened more than 300 times. (that's a lot to expect from a sheet of paper) Certainly a better solution could easily be adapted. I have an idea for a simple completely removable hatch that I plan to incorporate into my second Sea Duck.
Those really neat engine cowlings
Yes, I know those are really cool. I would love to post a link to them on Thingaverse but there isn't one. The cowls were designed and printed and given to me as a gift from a friend. I haven't gotten into printing yet but will try to get the file from him and upload to Thingaverse. It really makes the airplane! Sorry they arn't more readily available at this time.
Battery and Power System
My Sea Duck is operating with the suggested Flite Test C pack and I must say it is matched really well to the airplane. I have only operated it on 3s. It does everything very well on 3 cells. Takeoff and climbs are brisk. There is plenty of power for basic aerobatics too, but let's face it, takeoffs and landings and running around on the surface is where the fun is with this airplane. I'm sure 4 cells would be a kick but I decided I wanted to be kind to my esc's. The reason being, it wouldn't be fun to loose one in flight and the other reason is they are built into the airplane. Replacing one would be possible but NOT fun.
I'm using everything from a 2600 to 4000 mah packs. My timer is set for 4 minutes for all of them .(timer only runs above 40% power) If the big 4000 is on board I usually go an extra minute but that is about it. The C pack is a bit power hungry. It flys a little more spirited with the smaller battery packs but they also get hotter in the non ventilated fuselage. I think a 3000 is about perfect.
Actually there is a small vent on mine and on my friend's Sea Duck. Both of ours came out with about a quarter inch gap above the rear most bulkhead. This could be sealed but I though it might be good to let it vent. As it turned out, my duck leaks just a little (from where I don't know). The vent is handy for occasionally pouring a little water out from time to time. Or, you can do like I do and pull it vertical for a few seconds and make it rain! Happy accident.
This is one really fun airplane! The build, while not difficult at all is rather long for some reason? It takes Josh 30 minutes to build it in the video. It will likely take you 30 days.
I worked on mine for awhile and then but it away for awhile before finishing it. A little break in the middle of this build is probably well advised. Once it is finally finished and you fly it off of water on a calm evening, any memory of the long build goes away and you start thinking about how cool it would be to build a second one.
If you have never ever built a pre-fab kit from Flight Test but have always just built from plans, I STRONGLY suggest this be your first kit purchase. It takes 7 sheets of foam! The kit is well worth the price and it always feels good to support our FT friends and families by making a purchase. Also make sure you purchase the Y harness for the motors and the battery area reinforcement piece. In fact, go easy on yourself and order the C motor pack. It's GREAT!
Built one with a friend like I did. The airplane sounds amazing flying overhead. (Like a big old airliner) Two in the air or on the lake at the same time is spectacular!