Fokker DXXI

Fokker DXXI 

From Fly'n Foam RC

The Fokker DXXI is a modest step back in the complexity of my designs. After creating the Black Widow I decided to create something a little less complicated, but would still have the appeal that semi-scale modelers are looking for. I've always been a fan of the Fokker. It was a rugged diverse aircraft that served the purpose of it's pilots. It was very stable, and one of the only aircraft of it's type that could follow a JU-87 into a dive. This made the aircraft very valuable in it's time. Most of the build techniques for the Fokker are very simple as with my older designs but I have also used a few newer design techniques. Some of which were influenced by Nerdnic, and I would like to thank him for his contribution. I would also like to thank Blacbeltrrf for his contribution to this project as well as the Black Widow, and I look forward to working with him on my next design “The Do-335 Pfeil or Arrow. The Fokker is already available at Fly'n Foam RC, and the build module is posted on my Facebook Page. See build module here

Let's take a look at the Fokker

• Wingspan: 40”

• Length: 28.5”

• Wing area: 225 square inches

• Weight: 32 oz.

• Wing Loading: 21 OSF

• Motor: EMAX GT2215 1100 Kv, or EMAX CF2822 1200 Kv

• ESC: 20-30Amp

• Prop: 9 X 6 to 10 X 4.5

Beginning the build

Construction begins by cutting all the parts from DTF as usual. You will notice in this picture that the power pod is the un-modified version of the pod. This will be true for some parts in following pictures also, due to the fact that I make modifications as I create my initial version. 

Modified Power Pods

The Fokker plans include two modified versions of the power pod to accommodate either a 1300 MaH or a 2200 MaH battery pack as shown in the photographs. The batteries are secured into a battery receiver box and strapped in with Velcro. This provides a secure position for the battery, and ECS.

The Fuselage Frame 

The fuselage frame is standard of most DTF builds. Notice the circular cut outs in the center section. These are for the rare earth magnets that holds the canopy section / battery hatch in place.

The fuselage frame is folded and glued in the standard fashion. I prefer to keep the power pod handy to frequently test the fit. This prevents nasty little problems later in the build. 

The retaining rod holes are drilled in the power pod only after building the fuselage frame. This ensures accurate alignment of the holes. Special attention should also be used when applying the outer sheeting later. A special notice is included in the instructions to ensure that alignment of the retaining rod is true.

Rare earth magnets are inserted in the canopy deck plate to secure the canopy section to the air frame. Caution should be taken that the polarity is correct before gluing them in. this is accomplished by placing them on the fuselage frame so they connect with the magnets in the frame as shown in the picture on the left.

The canopy section / battery hatch is completed by adding the sheeting and canopy plate as shown.

The fuselage frame is typical of all my other designs. A box frame with former's and bulkheads supporting the skin sheeting. The Deck plate seen here in the fourth image helps to support the canopy frame. 

The canopy section is fitted to the frame to insure proper fit before sheeting.

The guides for the push rods are cut from coffee straws and the tail gear mounting plate is glued in place. The tail gear assembly is a Du-Bro .40 size tail wheel assembly. Catalog # DUB375. It can be modified prior to mounting with a control horn to connect to the rudder for a functioning tail wheel.

Tail

The horizontal stabilizer is a fully functioning airfoil section made from two layers of DTF as shown in the first two pictures. Te tail section is installed into the fuselage frame using a sub fin section. 

Sheeting

The bilge skin and turtle deck are cut from DTF and curled prior to mounting to the frame by removing the sheeting from the inside surface and curling it over a rod or pipe. The bilge skin is mounted first ensuring that it lines up with the rudder hinge line, F- 8, and the deck plate. Once it is in place trim out the opening for the tail wheel assembly and mount the assembly to the mounting plate.

The control rods for the elevator and rudder are connected and then the turtle deck is then glued in place. Notice the use of a steel ruler to hold the tabs in place while the hot glue cools. 

The cowling is formed by removing the paper from the inside surface and curling as shown in the first two pictures above. After wrapping the cowl around the frame and gluing. The tab is glued in the same fashion as the turtle deck.

The center sheeting, or wing saddle section is shaped by removing the sheet from the inside surface and curling as shown. When gluing carefully line the upper surface of the skin with the top of the deck plate and also F-4 and F-7 on one side only. Use a BBQ Skewer to make the retaining rod hole in the sheet then repeat the process on the other side. Picture 4 shows skin mounted and retaining rod in place.

Wing

The wing is the standard DTF wing build curling the leading edge of the upper surface for wing camber. The aileron servo is glued in place and DTF re-enforcement's are glued on top of the landing gear mount plate before closing up the wing as shown in picture four.

Gluing the wing is done in steps. First by folding the upper surface over the top. Glue the leading edge at the the split section to the top of the main spar. Then fold the rear section down and glue to the trailing edge as shown using a yard stick to hold it secure while the glue hardens. Dihedral supports are provided with the plans to help support the wing at the proper angle during the building process as shown in picture two.

Landing gear

The wheel pants are made by laminating several sheets of DTF pieces as shown above. The process Is fully explained in the instructions. Provisions have been made for adding or removing layers depending the thickness of the wheels you use.

The layers are built up to match the wheel thickness then the pants are sanded to a uniform round shape. Putty or filler can be used to achieve a smooth surface. The landing gear is then glued into place on the wings as shown.

The wing is then mounted to the fuselage inserting the tabs on the inner fuselage frame into the slots provided in the upper surface of the wing. A bead of hot glue run along the surface of the wing were it meets the fuselage side holds the wing in place securely. Use plenty of glue here as this seam will be covered by the wing fillets.

Wing Fillets

The wing fillets are made from two pieces, bevel cut and glued as shown. This process is explained in detail in the instructions. When complete they should look like the pieces in picture four.

The fillets are first glued to the trailing edge of the wing as shown in picture one. The aircraft is then turned upright and the fillet is glued to the upper surface. Use plenty of glue here also to help strengthen the wing mount.

The nose ring is then cut from 1” Owens pink or blue insulation foam. I like to use the clear gorilla glue here for it's filling properties and cure time. I used rubber bands attached to the motor retaining rod to hold it in place while it dried. It is then sanded to shape.

Canopy

The canopy is printed on standard printer paper. The window sections are cut from the sheet, and laminated as shown. Then the frame can be cut from the sheet. 

The canopy section is then painted to match the canopy, and it is glued in place.

The Fokker DXXI is a great little plane that you can take to the field that looks good, and flies as well as it looks. It is easy to build, and simple to prepare for flight due to the removable canopy section. The swapable power pod with previsions for 1300 or 2200 MaH battery packs make it a snap to change at the field, and the batteries are secure in each. If you are looking for a scale looking aircraft that doesn't take a lot of time to build and flies well then the Fokker DXXI is for you. As with all my designs the Fokker comes with a 21 page instruction packet and a link to the build module, full color decal sheet, and lamitated canopy frame. 

I'm sorry that there is no flight video available at this time due to my bad health and very unusual weather patterns this year. Blackbeltrrf has informed me that he has been dealing with a very personal issue in his life also, but will soon painted and ready for flight.

Feel free to visit my web page : Flyin Foam RC to get your copy of the plans for the Fokker DXXI, and brouse my Facebook page : Flyin Foam RC on FB. For the full build module go to : Fokker DXXI build module. 

Thank you and be on the look out for my next design 

The Dornier Do-335 Pfeil. "Arrow"