Some Notes About NX-211

Bob Coolbaugh wrote some comments about Charles Lindbergh's Monocoupe D-145 NS-211 SN D-125:

CAL’s D-145 was donated to the STL museum on condition that in be preserved in non-flying status, basically forever. CAL wrote the terms of the donation in a letter to the museum, stating that modifications to the aircraft made it unsafe for flight. He had flown roughly 400 hours in it, so he had a good basis for this opinion. 

The D-145 had a couple of control issues built into the design. The tailwheel was a vertical swivel post placed ahead of the rudder hinge line, making ground control challenging. Steering dynamics with rudder steering aft of the tailwheel swivel point are difficult. Add in the shortened triangulation with the main gear, making for more squirrelly steering and control. 

The main gear were not too different from bungee gear in the Models 90/110 except in the way the gear were sprung. The D used a one-off cantilevered shock piston system instead of bungees. As described, landings were more unpredictable because each gear leg would move differently on touchdown, especially challenging in a crosswind. This is as described as I’ve never spoken to a 1930’s D pilot. 

I have been briefed by Johnny McCulloch about his time flying Big Butch. He had a leaf spring tail wheel extending aft of the rudder hinge line. He had juice brakes. He also had unmatched skill as a Monocoupe pilot. Well, perhaps Woody Edmondson was better. Maybe Johnny Livingston. “Chainsaw” said it flew fine, was not unusually tricky to land. 

The main reason CAL wanted his D grounded, though, was because of his modified ailerons. He worked with the factory to create ailerons that drooped with flap extension. This turned out to be a headache for the guys, caused several long delivery delays and never really functioned effectively. It was a case of improving the airplane to the point of unsatisfactory performance. I believe that is the main reason he permanently grounded NR211.