DH C-2 Beaver
De Havilland DHC-2 Beaver
Based on the famous bush plane, this model has many characteristics of the original. Rugged and simple like the real thing. This makes it perfect for a seaplane upgrade. Attach the floats and have fun on the water. It will fly predictably, but since it lacks ailerons it’s aerobatic qualities are limited.  But, with the weight and drag of the pontoons you can forget about the aerobatics anyway. It will not fly as slow as my Tigermoth, yet it is more of a trainer than my ME-109. My Advice is to practice with the wheels on land and then bring a fishing rod (and hook) with you to the water runway to tow crashes back to the hanger.

You’re gonna like this:
-Decent wing dihedral makes this an easy to fly three-channel airplane.
-The DHC-2 has pre-marked locations for float installation, and GWS sells the floats for $13.
-Easy brushless motor conversion using GWS gearbox and mount.

You might not like this:
-In a full throttle dive wing flutter may develop.  This can be fixed, but it seems to be a design flaw that could freak-out a newbie.
-Boring white color scheme makes it look like a cheap toy. Ohh, but there are nifty stickers.
Best stick config:
Powerplant:  EPS 350C geared 5.3:1
Controller: GWS 8 amp esc
Cells: 6N270~400mAh (NI-CD) / 6N500mAh (NI-MH) or, lithium polymer 2 cell 1200mah
Prop:gws 10 x 8

Best tuning config:

Powerplant: himax brushless 2015 3600 (weighs less than the EPS 300!)
Controller: Phoenix 10 amp esc
Cells: 3 cell Lithium polymer 800mah
Prop: GWS 9 x 7 three blade prop
Beaver Tips
There are many good reviews on the net covering the basic construction. Here at
http://www.rcgroups.com/links/index.php?t=display_link_search&having=127840&cat=156, are two reviews. One on the basic construction, and another on installing floats-- both excellent and by Michael Heer. I will just expand on some of the finer details.
1. The first issue deals with an aerodynamic problem with the DHC-2. It has been written about on the net, and is real enough that GWS has written a performance advisory bulletin.  See it here
http://horizon.hobbyshopnow.com/products/description.asp?prod=GWS1030 at the bottom of the page.

GWS PERFORMANCE ADVISORY: For higher performance where aerobatics or faster-than-scale flight is planned, we highly recommend a further strengthening of the wing by using four pieces of 3/4-inch filament strapping tape applied as illustrated. This will reinforce the wing in the areas shown on the bottom and top of the wing.  This eliminates wing flutter that potentially can occur during a high throttle dive (normally not recommended). You can also slow the air speed slightly by replacing the included 10 x 8 propeller with an 11 x 4.7 propeller, which will provide more realistic performance.

It refers to wing flutter at high speeds. So for example if you put your plane in a dive you may see the wings flap and shake (flutter). This can be very disconcerting, and is most likely caused by turbulence and wing rotation about anchor position of the wing strut.  GWS’s fix is to add strapping tape to the wing to add stiffening. I am sure this will work well enough, but I consider it a rather crude solution--especially if you have already applied the wing decals. Others have added an additional wing strut, which I consider a good, if not a scale real world solution.  I have come up with a more stealthy solution though. I glued a 1/16th carbon fiber rod to the leading edge of the wing. I then reinforced this with fiberglass and water based polyurethane. This does two things. One it stiffens the wing and two it protects the leading edge from impacts. You could use a wood or bamboo rod instead, but nothing beats CF. Next I placed a reinforcing rib where the wing strut meets the underside of the wing. This transfers the rigidity of the leading edge to the trailing edge—the lack of which is the source of the wing flutter.
2. Points of weakness: On all foam models there are points of stress that tend to crush or break from stress. Also known as crash landings.   On this plane these are the wing tips, leading edge, and the landing gear insertion points.  These are all easily reinforced with fiberglass with minimal weight gain.
3. It can be helpful to add a small support for the servo rod guides. This is so that the rods do not flex, and prevent crisp control.
4. This may be a minor point, but the windows as described in the manual are not scale.  That is to say they don’t look like they do on the real thing.
Beaver Tuning
This plane is ideal for a Seaplane conversion.
Of great importance is weight reduction since the floats add 4 to 5 ounces on their own. Accomplish weight loss by using a feather receiver, pico servos, and Lithium batteries.

Change the long wire antenna to a micro antenna that is internal to eliminate the wire dragging in the water.

Brushless-motor upgrade. Sometimes fighting the waves and bucking a head wind require more power. I like the Himax series that fit into the GWS gearboxes. You have to increase the voltage of course, but the gains are probably worth it—for a price.  See the rest of this web site for brushless upgrades. I like the Himax since it is the least expensive of this type of motor, it comes it a large array of sizes, and with an adaptor plate and pinion you can just screw it into a GWS gearbox. This allows me to swap motors.

Floats addition. For extra strength, it can help to fiberglass the landing struts where they meet the fuselage. And, water in the floats can be a problem if they are not sealed properly. My suggestions include iron on coatings, packing tape, or fiberglass and polyurethane.

Waterproofing the electricals. The electronics are the only parts you can really ruin if you dunk the plane. I protect most with silicone sealer over the shrink-wrap openings of the esc, receiver, and battery. I also tape the battery-esc connection. Put grease in the servo guide wire tubes where they exit the tail.

Propeller. Switch to a three-blade prop (smaller diameter) to limit the chance that it catches the water and flips you.

Water Handling. Taxi to get the plane into the wind.  Don’t rudder steer downwind into an up wind position. The wind may get under the wing and flip you. Start the turn with the rudder and then get off the power and let the plane “weather vane” into the wind. For take off into the wind use half throttle and full up elevator to keep the nose up. Once the plane starts to rise up—on step, then level the elevator, and apply full throttle and lift off.  Land into the wind. Just remember crosswinds ditch real planes as well as models.