DG-808S COMPETITION

The climb specialist – now fit for “fast” days

by Gerhard Marzinzik in Aerokurier 12/2003

Climb performance was always a stronghold of the DG-808S. But with a maximum wing load of 10.4 lb/sqft (50.8 kg/m²), the Competition version turns into a racer between strong thermals. For this flight report she has demonstrated how good she accommodates the 530 lb (240 kg) of ballast

The DG-808S at the World Championship

Ralf Fischer flew the DG-808S Competition in the 18m Class at the World Championship. He had two superior winning days, and narrowly missed a third win due to an outlanding. Another unlucky outlanding during the catch-on race placed him finally in the midfield.

AK: Ralf, what was your motivation to fly the DG-808 Competition during the World Championship?

RF: I’m flying a DG-800S since several years and are convinced by the airplane. In particular I like the good view out of the cockpit. The safety cockpit and the emergency egress system NOAH were convincing points besides the increased wing load.

AK: How did you utilize the possible high wing load of 10.4 lb/sqft (50.8 kg/m²)?

RF: In Leszno I always started with the maximum weight of 1323 lb (600 kg). The filling of the 63.5 US gallons (240 liters) ballast didn’t cause a significant delay. We were ready only 45 minutes after we pulled the fuselage out of the trailer.

AK: With which wing loads did you typically arrive at the end?
RF: In Poland we flew most days in strong weather conditions. I drained the ballast water only at my three outlandings in approximately 1600 ft (500 m). And there was another flight when I was very low. I guess I drained about 10.5 US gallons (40 liters) before I found a thermal again. Otherwise I arrived always with full ballast. The DG-808S handles the high wing load very well. Even with 1323 lb (600 kg) I had slightly better climb performance than competitors flying the new Ventus 2cx, which allows a wing load of 10.5 lb/sqft (51.2 kg/m²).

AK: How do you value the slightly higher aileron control forces of the DG?

RF: They don’t really affect me. But I have a calm style to handle the controls anyway. Maybe I don’t notice the control forces since I apply polish underneath the gap-covering tapes once a month to keep the friction low.

AK: How did your straight flying performance compare to your competitors on LAK 17a or Ventus 2cx during the World Championship?

RF: In the beginning I flew partially together with Bostijan Pristavec on his LAK. He had to drain water to keep up with my climbing performance, which turned into a disadvantage for him during straight flight. There is not much difference between the Ventus 2cx and the Competition in straight flight. The team flying with Wolfgang Janowitsch during the last days allowed me a comparison. After long glide distances I usually had some reserves for trials left and right. But maybe Wolfgang could not fly as relaxed as me due to the pressure of defending his leading position for the title.

Interview: Gerhard Marzinzik

Ralf Fischer appreciates the

DG-808S Competition

About 17.2 US gallons (65 liter) more capacity have the tanks of the DG-808S in the new Competition version. This results in a maximum take off weight of 1323 lb (600 kg) for the 18m configuration, equivalent to a wing load of 10.4 lb/sqft (50.8 kg/m²). Structural reinforcements of the outer wing section made these increased loads possible. Two additional fuselage tanks provide the additional capacity. They compensate also the center of gravity drift caused by the ballast in the wing tanks. The fill and drain openings for the wing tanks are on the lower wing surface. The fill openings for the fuselage tanks are directly behind the trailing edge of the wing located.

A separate drain control lever controls each tank group, the inner wing tanks together with the forward fuselage tank, and the outer wing tanks with the second fuselage tank, which is also located in the forward empennage. The main ballast system with 16.4 US gallons (62 liters) each in the inner wing tanks and 7.8 Us gallons (29.5 liters) in the fuselage tank; and the second ballast system with 9.25 US gallons (35 liters) in each outer wing tank and 3.6 US gallons (13.5 liters) in the fuselage tank can be controlled independently. The well thought-off arrangement of the tanks avoids any center of gravity drift, even if only one system is drained.

The DG-808S received also structural enhancements in the cockpit area to increase the protection for the pilot. But in contrast to the DG-808C the added lateral stringers take up less space so that no cockpit room is lost. On the other hand, the DG-808S cockpit has a narrower design than that of the “B”.

As a further safety detail, the DG-808S comes with the “Piggott Hook” (named so by DG) as standard equipment. It prevents the self-extension of accidentally unlocked air brakes. The Competition flown for this report was also equipped with the optional bug wiper garages. This aerodynamically clean stowage of the bug wipers appears to be a good investment. Bug wipers normally parked in the open slipstream of the win-fuselage intersection have probably the same drag as a slight bug contamination of the wing itself.

I tried the fully loaded Competition in strong North-Easterly wind at the Bruchsal airfield. With the maximum permissible 1323 lb (600 kg) in tow, the Remorqueur took slightly longer to get the DG-808S airborne on the grass runway. The take-off with +10 degrees flaps was unproblematic, even in the prevailing crosswind. There is no need to change the flap setting during take-off, even with maximum weight.

The outside view during the tow is good, and there is little need for corrective control inputs even in turbulent air. The Competition stays stable behind the tow plane; the high wing load is not noticeable. Also after release no influence on the handling qualities could be noticed due to the increased mass. The docile slow flight handling stayed the same, with a stall speed of 44 kt (82 km/h) with 0 degrees flaps. With +10 degrees flaps the stall speed is slightly lower; and with minimum wing load more than 5.5 kt (10 km/h) lower.

S-turns from 45 degrees to 45 degrees bank performs the fully loaded Competition in approximately 4 seconds at 60 kt (110 km/h) with +10 degrees flaps. This is hardly noticeable slower than with empty tanks. The maneuver requires noticeable aileron forces and strong rudder input. These characteristics are similar with empty tanks. However, a typical thermal flight mission does not require 45 degree bank S-turns, so that those control forces are not important. In thermals the DG-808S shows a very balanced control characteristic, providing me a lot of fun in these narrow and turbulent late-autumn thermals. The 808 follows willingly and promptly each control input, it was an easy play to direct her into the zones of best lift.

With a wing load of 10.4 lb/sqft (50.8 kg/m²), she must be flown with 60 kt (110 km/h) in tight circles up to 45 degrees bank; with turbulence she requires even 65 kt (120 km/h). With empty tanks she can be flown with lazy 43 kt (80 km/h) or even less.

To summarize after two hours in late-autumn thermals: The DG-808S Competition handles the increased load very well. No influence on the handling qualities could be noticed. However, her performance spectrum improved significantly. With 10.4 lb/sqft (50.8 kg/m²) wing load she is ready for “fast” days. And her strong climb performance on weak days is already well known.

Gerhard Marzinzik