Saturday, April 11, 2009
Mugi Tea Racer: Another Hit From Across The Pond!
The Tea Racer has flown! Numerous flight tests this morning concluded however that I have too much positive incidence in the wing. Apparently I didn't cut the wing saddle out deep enough, however this is easily remedied by simply cutting it deeper. Now I just hope I can find the template that I made so I can keep the shape right.
On the first takeoff it appeared that the plane was tail heavy, even though I had purposely balanced it a bit nose heavy for the initial flight. It lifted off the ground by itself long before I was ready, then porpoised badly all the way back around to a rather disgusting but thankfully damage free landing. I moved the battery farther and farther forward on subsequent flights until the thing was so nose heavy that it would barely set on the landing gear without nosing over, still no joy.
I then greatly reduced the elevator throw and programmed in a ton of exponential, still it was extremely sensitive on the pitch axis. A closer look revealed that I had a ton of down trim in an attempt to attain level flight, even though the plane was now obviously nose heavy. This is a dead giveaway for excessive wing incidence. Also the plane would tend to want to climb more and more as speed was increased, which is another dead giveaway.
It did however, accelerate dead straight with no pitching tendencies on throttle application, so the thrust angle must be in pretty good shape. Also, even though the wing was running far too high of an angle of attack, the venerable Tea Racer showed absolutely NO tip stalling tendencies at low speed, which is truly amazing for a plane this small. This, coupled with the fact that even though this plane feels a bit heavy for its size it glides FOREVER, is a testament to Morgan's design ability.
When I get the wing incidence right, this thing is going to be an absolute JOY to fly. It already shows potential far beyond several factory made planes that I own with no doubt MUCH more money poured into their R and D. The takeoff run was basically uneventful, with only a tiny application of right rudder necessary to maintain a straight track, and once again, even with the incidence issues I can tell that this plane will practically land itself once it's flying the way it's supposed to. So far I'm impressed, and I can't wait to fly it once the wing is pointing where it's supposed to be.
Oh yeah, did I mention that it's FAST! I couldn't really open it up for obvious reasons, but I did manage one or two high speed passes with a victory roll or two thrown in for good measure. It's not called a Tea RACER for nothing! This thing is going to be a blast, and judging by the interest it generated at the field, I won't be the only person around here flying one for long.
So overall, my opinion of the Tea Racer at this point is pretty high. The incidence issue is my mistake, not a flaw in the design, and hopefully I'll be able to measure the actual incidence when I get it figured out so I can post it here as well as on the Mugi Forum. Even so, there are many variables when folding a Coroplast wing, so your mileage may vary.
The tailwheel? It performed flawlessly, no ground handling issues whatsoever unless you count the nose over tendency the plane had with the battery crammed too far forward. My main gear mounting methods are subject to review however. It seems that the hardwood blocks I used to secure the gear should've been anchored somehow to the wing spar for added stiffness. I'll revise that on version 2.0 and see if I can't come up with something better. For now they're getting some glue shot under them so the testing can resume.
What are you doing reading this? Get your butt busy and build a Tea Racer, you'll be glad you did!