Airdrome Aeroplanes ~ Holden, MO

There is an old saying:
"Better" is the enemy of "Good Enough."

     In spite of that great advice, several modifications have been made to the Nidnoy D.VII since the first PIREP of 9/1/06. The first was to add a new Culver 80x53 maple/mahogany prop. Performance was similar to, but slightly better than, the GSC Tech III 72x54. However, with the new prop, engine rpm was limited to max cont.(5,800 rpm). The aircraft was still butt-ugly with the original cowling.

     I have since:
             1. Inverted the gearbox on the HKS engine;
             2. Raised the engine 6"with a new motor mount;
             3. Changed/lengthened the exhaust pipes;
             4. Modified the cowling for the new engine configuration;
             5. Gap-sealed the elevators.

     The cowling has been extensively modified to compensate for the raised engine and changed motor mount. The thrust line is unchanged vertically, but modified approx. 1 degree left to compensate for the new prop (which has complicated the cowling mod).

     The old exhaust system was an HKS Type I, (approx 18" from the cylinder head to the "tee" before the muffler.) The new custom exhaust is approx. 29" from the cylinder head to the "tee." The "tee" has been shortened approx. 2" from the HKS stock condition.

     New maximum engine rpm is 6,200! The aircraft seems to have improved climb.
Handling remains unchanged (still great), but the "feel" is better because the aircraft now no longer feels underpowered.

     General handling is very similar to Travis Gier's Dr.1 When I remove my feet from the rudder pedals at cruise, the aircraft tracks straight, with no yaw instability. Removing my hand from the stick, the aircraft flies straight and level (if the fuel load AND mine are just right!) Control forces are light, but not "twitchy." Stalls result in a "mush" (no real break) but a HUGE sink rate. This aircraft seems to have the glide ratio of a DROPPED rock-- VER LOW INERTIA!!

     All landings, thus far, have been done three-point to paved runways. No unusual tendencies toward groundlooping have been noted. (It IS a taildragger, after all, and must be "flown" all the way to the hangar.)

              Top speed:     85 mph IAS @ 6,200 rpm;
              Cruise speed: 65-68 mph IAS @ 5,200-5,400 rpm;
              Stall speed:    40 mph IAS.

     All in all, a great improvement! The airframe ALWAYS handled well, with no surprises. Now that it has adequate power,....

     I'll be happy to answer any other questions.

John B. Hyde