Fly-Fly Models DG-1000

Jun 18, 2009 No Comments by

Author: Adrian Muiño

“DG Flugzeugbau GmbH” is a manufacturer of sailplanes founded in the 1970s and based in
Germany. In July 2000, they commemorated their 25th anniversary with the debut of their new creation: the DG-1000. It was the evolution of the three previous DG models. The DG-1000 is a two-seat glider with a maximum speed of 270Km/hr, a weight of 750kg and a glide ratio of 46.5.

HobbyKing is distributing the Fly-Fly Hobby Models DG-1000, a 104 in. scale of this successful airplane. After more than 50 successful flights, here’s the product review of the powered version. As usual, the model arrived on time and well-packed in a single cardboard box. Each piece was carefully covered, placed inside and all in white. The graceful fuselage is made of fiberglass and there are very narrow, laser-cut balsa wings—talk about a fast and efficient sailplane! The included accessories are complete and there are also some scale decals and markings. The user manual has only one A3 page (which is like a double A4) and many symbols and few texts.

Specifications
Model: DG-1000 Fly-Fly Models (Hobby King – hobbyking.com)
Type: slope glider semi-scale
Wingspan: 2630mm (103.5 in.)
Profile: HQ-3012
Length: 1130mm (44.5 in.)
Wing area: 28dm2 (434 sq. in.)

No. of channels: 3, 4 or 5
Weight: 1500g-1700g (3.3 lb.-3.74 lb.) powered version

Price: $130

hobbyking.com

Assembly
The construction of this model is very simple and because each part of the work is quite independent, you can start where you feel most comfortable. Leave the LiPo installation to the end to allow an easy CG adjustment.

I started assembling the stabilizer. It requires a careful sanding at the top where the fin will sit and be attached; the goal is to have this surface parallel to the wing spar. You can see in the photo how I use two levels for the verification. The stabilizer is attached to the fin with two steel screws and can be easily removed for shipment and storage.

The elevator servo is placed at the top of the fin, making the linkage strong and simple. I attached the servo directly to the structure of the fin and then covered it. In the elevator and ailerons, 32-inch extensions are needed and in both surfaces, the servos have to be thinner than 1/2 inch if you want to keep them embedded in the structure.

The rudder has to be hinged and is moved by a classic pull-pull. I increased the outlet of the pull-pull in the fuselage in order to help evacuate the airflow from inside through the aerodynamic effect. Due to the pull-pull system, it’s advisable to use a ball-bearing servo.

The elegant wings require little work. When installing the aileron servos, the main difficulty lies in passing the cable through it. The ailerons, like the elevator, come mounted and hinged, which saves assembly time. I give some mechanical differential to the ailerons, putting the horns holes 2mm ahead of the hinge. To fix the winglets, a preinstalled rod must be placed and epoxy applied. The winglets dihedral can be matched with a help of a block. Attention must be given to its incidence; it must be the same as the tip of the wing. Two metal rods determine each wing incidence. It’s important to check that both wings have the same incidence, and move some of the rods if it’s needed. To check this, you can put the plane upside down and place levels on the wings or use incidometers if you have them. Wings are joined together by a rubber band. I replaced the 6mm steel rod for a carbon-fiber one, saving 100g. To improve the visibility, I first added on the intrados black strips, and later orange flou strips, both made of Oracal.

The ESC, the receiver, the LiPo pack and the Rx pack were mounted with Velcro. This is ok only if you are not going to do aerobatics. As usual, the larger the distance between the receiver and the ESC, the better will be the reception.

I painted the cockpit in light blue and set the cabin with four magnets, plus a little carbon rod in the front, which made the access to the LiPo pack easy.

The motor mounting is simple and is done by four screws that trespass the front plywood. I put a paper over the motor-mounting surface, marked the holes with a pencil and then passed them to the F1 plywood and made the holes. I made some extra holes for ventilation. The cone should be 28mm in. diameter, although I used a 30mm aluminum one with no problems. There is also a version without the F1 that lets you cut the fuselage and fit the motor and the cone where you would like. Ventilation is always a weak point in gliders and this is not the exception. I made holes below the motor to receive the fresh front air, and behind the cockpit, where the low pressure takes out the inner air. Maybe the best method could be to use a cone with a central air intake.

Programming
The surface movements used are enough for agile control of the model, even in the low rate, but maybe you’ll prefer to lower them 20%. The use of some exponential is also advisable—starting at -30%. After some flight tests, I programmed spoilers at 18 degrees and 36 degrees, and they worked very well. Over the elevator I made two mixtures. One with was with the throttle at 8%, lowering it when the throttle went up; and another for the spoiler 7% up when they were deployed. I did not mix rudder with aileron. I give 30% of differential too.

With a 550W/lb. power-to-weight ratio, the model can be safely hand-launched after a little run, even in crosswind—not bad for this heavy bird! It can climb at more than 75 degrees, and in an eventual tip stall, it has enough power to save the model (do not ask how I know). The autonomy is 9 to 11 minutes with motor, plus the soaring time. Anyway an 11,1V LiPo configuration at 330W moving a 12 inches propeller will be more balanced and will save some valuable grams too. In order to be on the safe side, I preferred to add an AAA NiMh pack for the radio instead of using the BEC.


I started with the CG location at the specified point, and after several adjustments in the stabilizer decalage, the CG was now at 35mm from the leading edge at 200mm of the fuselage. To test the CG, I used the dive method.
 
Radio and Power gear

Radio: Multiplex Royal EVO 9
Motor: Hyperion 3013-14 (110g and 1085 rpm / v)
ESC: Hyperion 50A
Motor Pack: LiPo 4S to 2200mA 25C
Rx Pack: 4.8 V NiMh 900mA

Servos: Torque at 4.8V 3kg,12mm wide
Propeller: 9×5 folding
Autonomy: 10 minutes powered, plus the sailing time

Highlights

Beautiful scaled shape with large cockpit
Fast and efficient flight
Well finished and robust fuselage
Excellent value for money
 
Conclusion

I think everyone likes the scale airplanes, especially if they are elegant and big, and the DG-1000 distributed by Hobby King is a great example. The kit is easy to assemble; the structure is sturdy and has an excellent cost-quality relation. It is neither a toy nor a high-performance slope sailplane, but with an eye-catching design and a neat style, it will provide many hours of enjoyment.

In the air

Once in the field I assembled the model. Placing the rubbers joining the wi
ngs took time, but with practice it is not so difficult. I checked the CG again, tested the radio range and measured the motor performance. It was Sunday morning, the wind was strong and crossed to the runaway, the temperature was high and the pressure low. It seems that quiet summers are history. I asked a friend to launch the model. After a little running, the DG-1000 was in the air and went up steadily while flexing its wings.

The only surprise was that I had to trim the elevator down a lot, and I gave more negative to both the stabilizer and the motor. The speed of the model was also noticeable; well over the classical 2m thermal sailplanes. The combination of the low visibility and the high speed makes you have to pilot the plane 100% of the time—exciting! The model responds very well to all the controls and can fly in strong wind with no problems. Be sure to not let it slow down, because it will drop a wing suddenly.

When it was time for landing, I made several passes until I found the right path. The maneuver was successfully completed, but it took all 600 feet of the runway. Although the speed was high and the soar long, the landing was firm and solid, even with crossed wing and turbulence. To reduce the landing path and secure the landing, I added spoilers and programmed the ailerons. They gave a soft, but very defined slope, which reduced the use of the runaway to 300 feet or less.

Pilot debrief

In the afternoon the people started to come, and the DG-1000 captured the interest of everyone, even those who were not glider pilots. This really demonstrated the realism and excellent style of the model. Once in the air, the DG-1000 was nicknamed “the Jet Glider,” and since then it has been the standard for speed comparison. My favorite maneuver is the “stall turn” (also called Chandelle). First, you do a peaceful, low-altitude pass over the runaway facing the wind, climbing at full power. You then turn and make it whistle in a 60° dive before passing low and furiously fast. Big loops are beautiful, too, but fasten all stuff first and take care of the Gs at the end.

 Sidebar: Takeoff and landing

With several flights performed and the trimming done, I am now able to hand launch it by myself. Once in the air, and before passing from the powered flight to gliding, the nose must be set down and the speed assured.

In my case, the landings are not simple, because trees and buildings surround the flying area, and the runway is relatively small. The motor helps a lot because it permits to abort if necessary. I solved the maneuver the way the real planes do. I started the downwind leg at a prudent 40 to 60 feet. Then I made a very flat 90-degree turn, but let it go down without losing speed. I gained even more speed in the basic leg to safely complete the last 90 degree turn (sometimes I need to give some motor at this point). After the turn, the model is in the final leg and should be aligned to the runaway and about 20 feet above the ground. At this point, I deploy spoilers (18 degrees if the wind is over 6 mph or 35 degrees if there is no wind). The model then starts to lose altitude constantly and only a final up-elevator is needed to end the landing, rarely the use of the ailerons or the rudder is needed. Under no circumstances should you let the plane slow down. Always keep the nose down, particularly in the turns. It is not a floater and at low altitude it will not forgive you.

Powerplant

 

 

Motor

Hyperion 3013-14

 

LiPo

4S 2200mAH, 25C

 

ESC

Hyperion 50A

 

Propeller

9×5

folder

Voltage

30

A

Current

14.4

V

Power (input)

432

W

Autonomy

10

min

Trust

3.7

lb.

 

 

Low

High

 

Exp %

Aileron up

11

15

mm

-50

Aileron down

7

10

mm

-50

Elevator

3

4

mm

-50

Rudder

22

26

mm

-40

Spoiler

8

13

mm

-

 

 

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