RCU Forums - DH-Comet

I flew one this weekend. My Friend, Dick Durant called me Saturday evening saying that he got his DH88 Comet ready to fly and asked if I would do the honors. I had tested his Gee Bee Z a year or so ago so I knew that his Comet would be built with great care. I also have the same airplane but mine is not far enough along to get it flying. I am disgusted with the shoddy parts that are supplied for the Elevator and Rudder controls as well as the tail wheel setup. Not being very creative, I had shelved the project while I decide how I can get the job done correctly.

Dick had his Stabilizer installed when the welds broke loose so he had to surgically remove a small !QUOT!hatch!QUOT! behind the stab in order to repair the situation which left a scar. Global should be shamed for putting out this kind of product. Most everything about the model is great for an ARF except a few things that are dangerously insufficient and take the fun out of building their model.

Dick installed two O.S. .61 Four Strokes for power and they went in very nicely and remained completely cowled. He didn't want the mufflers to show so he left them off and the engines don't sound any different without them and only the short header sticking out of the cowl. He also ran remote glow adapters to the top of the cowl for ease of starting. He installed a small flashlight lens in the nose behind the clear nose cone. A micro switch linked to the retract servo activated the nose light when the gear were down.

After a radio range check he fired the engines which had been run and tuned at home so there was less stress at the field. They sounded beautiful and held a pretty good sync throughout the throttle range. The wind was 10 - 12 but at Rabbit Dry Lake, it is "Clean air" with little turbulence. Mostly only created by the vehicles in the pits so knowing that, the wind becomes an aid in a test flight because it slows the ground speed down for take-off and landings.

The airplane was not taxied since it seemed very light for the wind. One run down the runway just to see what it would take to get the tail off the ground. Carried it back to the approach end for the first flight. Both engines came on very smoothly while watching for any unequal pull and corrective rudder needed. The "bail-out" here would be to cut the throttles prior to wheels lifting off. No problem. The tail came up easily and by the time the stick was at half throttle the airplane had broken ground. We were flying! The ailerons are a piece of crap 'cause they don't even match the thickness of the wing. So Dick had tried to center them as best he could between lining up the inboard edge and outboard edges with the wing structure. The airplane banked to the right slightly requiring about 4 clicks of left aileron trim. Before take off I asked him about the Balance and he said that it was "slightly" on the nose heavy side and that was good news. I noticed that it took a few clicks of up elevator trim during the climb and after leveling out on the downwind side. I also noticed that I was still at half throttle. Dick had differed from the meager instructions and did NOT glue the wing tips on. Instead he created a plywood "hard spot" on the bottom of the wing within the gear area of the nacelle. He, then, drilled a hole through the bottom of the wing and through the aluminum wing "spar" tube and threaded the 4-40 bolt into the aluminum tube. This enabled him to remove the wing tips for transporting and keep the wing center section attached to the fuselage. I wanted to take it easy on the wings at first so I purposely kept the speed s down.

Once trimmed, I flipped the gear switch and the gear retracted nicely. Suddenly, Dick gasped and said that he had forgotten to air up the gear before take-off. I asked him when was the last time he had aired up the gear (expecting to hear "last night") and he said "about a month ago". Gee, they went up alright but will they come down? Needing to know the answer to that question while we still have fuel to make a decision, I flipped the switch back down and the gear came down nicely. Our luck was good and not wanting to press it, I left the gear down for the remainder of the 1st flight. We evaluated the role rates since Dick tried to adjust the throws as per the Meager instructions. They didn't say whether to measure the throws at the inner side or outer side of the ailerons so Dick put the high rates according to the outer measurements (I believe 3/8") and the low rates were according to the inner side measurements. It turned out that the High rates were just right for my taste providing a gentle roll rate that was appropriate for the size and type of plane. I did not do any rolls or loops during this test flight as I usually do with other airplanes. The Comet was strictly a cross country racer and it should be flown in that style. Once comfortable with the trims and rates, I inched the throttles up to full and, again checked the trims. No difference. Keeping my turns smooth it was a beautiful sight. No Pylon turns yet. I did however take advantage of the maneuver that I am sure the Brits exercised most frequently and that is the "high speed buzz job" over the field. This provided a few spectacular photo opportunities for those that had cameras. Nobody brought a camera except me and I was busy flying. We knew we hadn't seen the full speed since the gear were still down and we needed to get her down and put the proper air in them.

Throttling back, the engines maintained their sync and the Comet showed how clean it is by holding its airspeed throughout the approach not needing any power to carry it into the 10 mph wind. I purposely kept the speed up with a slightly high approach since I had heard all the above talk about "tip stalling" etc. This was not a problem. I touched down on the main wheels while the tail kept flying. I could "feel" the spring loaded struts doing their part to help the Comet "settle" onto the lakebed. It was a very good feeling and Dick was a very happy man. He was almost giddy. :-)