So, after a week of airplane withdrawal shivering and shaking with the cold sweats -), lying on the beach in Wellfleet on Cape Cod with a stack of friends and their children, I went to the airport this morning (Tuesday) with the intent to just go up for a short flight, refamiliarize myself with the plane, and do them old accelerated stall tests.
Just for the record, I appreciate all the supportive emails regarding these reports. I write them for three reasons - one, because I've got to take the data anyway and I'd put the writeup on the web page, so it's no extra work to send it to the list. Second, I fully appreciate that I'm NOT a test pilot in any way, shape or form, but while my aircraft is different from all other aircraft, it's not THAT different (I hope). My reports should confirm the basic characteristics of the COZY MKIV, and if they don't, I'm hoping that getting feedback from other flyers will help me to determine why the heck not. Third, I would have KILLED to get reports like these from the other 30 - 50 COZY MKIV pilots on the list, as they test flew their aircraft - I didn't have much of a clue at all what I was in for, how complex it could be, how rigorous it SHOULD be, and exactly what I was trying to achieve. I'm hoping that writing this will provide this input for those still building. OK, enough of the rationalizations -).
I decided to just fly from FIT to EEN (about 30 miles, past Mt. Wachusetts and Mt. Monadnock) just to go to someplace new and do a landing/take off cycle. I cruised at about 160 mph, the air was smooth, and I turned on the Navaid and set the pitch trim and just looked out the canopy for a few minutes. It struck me that I hadn't tried to turn on the heat yet (being that most of my flights have been at an ambient temperature of 95 - 100 deg. F) so I pulled the knob. Lot's of air, that's for sure, shot out at my feet, but even with the engine at 2400 RPM, the air wasn't particularly warm. Hmmm, that's probably why I don't notice any real difference (10 RPM, maybe) when I turn on carb heat. Have to take a look at that muff, and see why. Not important for another few months, anyway.
As I lined up on final for EEN's 6000 ft. runway 02, I pulled up on the landing brake handle and POP - the handle came up, but the brake didn't go down. Not a big deal - I chopped the throttle, landed a bit long, and while taxiing back, realized that one of the cables had popped out of the nicopress sleeves back at the rear pulley. That had happened once before, about 5 years ago, in the basement. So, one more thing on the list of stuff to fix/robustify.
I departed EEN for FIT, flew over Jaffrey airport just to scope it out, and then headed back for the Mt. Wachusett practice area. Ground speed 189 mph, indicated airspeed, 160 mph. That's the fastest GS I've seen in a small plane, that's for sure.
I slowed down and did some straight ahead stalls. Power off, I was getting about 65 - 67 mph indicated (remember that my airspeed indicator is off by about 5 mph at 70 mph, so the calibrated airspeed would be about 70 - 72 mph). This was at a CG of 100" - 100.5", and a weight of about 1525 lb. - 1550 lb. I would get the nose bob with the elevator pulled back about 80% of full deflection. If I pulled the elevator back all the way, the bobbing would just about stop, and I would be at 67 - 68 mph or so.
I then added a bit of power to keep my descent rate 0 fpm, and the bobbing went away also. I then started the accelerated stalls by maintaining a 15 degree bank angle, adding power to keep the descent rate 0 fpm, and slowly pulling back on the stick. Here are the indicated stall speeds for various bank angles:
0 deg. - 65/67 mph
15 deg. - 68 mph
30 deg. - 70 mph
45 deg. - 72 mph
60 deg. - 78 mph
Now, at 78 indicated, at a 60 degree bank angle, I felt like I was taking a ride in a spin dryer. You whip around pretty good, and I didn't like to keep my head in the cockpit the whole time watching the VSI, airspeed indicator, and AI, so I'm not sure how accurate the 45 and 60 degree speeds are, but they're pretty close, I think. They don't quite seem high enough, given the G loading, but hey, that's what I saw.
At any rate, the plane was fully controllable, even at 60 degrees of bank with the stick full back at that absurdly low speed. It struck me that if I ever needed to thread my way down through a cloud hole that was barely bigger than the aircraft, this would be the way to do it - I felt like I was pivoting on the lower winglet. (The actual radius of the turn is something like 250 ft - haven't done all the math, but it's a whole lot smaller than any other turns I've done -) ).
Went back to FIT, landed, and realized that I'm getting used to putting the gear up and down. That's a good thing -).
So, no problems (none expected), and no danger. Just gotta fix the landing brake and change the oil (now that I'm at 9.9 hours). Still got the oil temp. thing to deal with, but thanks to a lot of suggestions from the COZY Unofficial Builders mailing list (which I wouldn't have had if I hadn't been doing these test reports) I've got a bunch of things to try.
Next will be the full set of slow flight / stall / climb tests at constant CG's and weights.
There is no real Flight Test Protocol for Flight 9 - it's all in here.
|[Zeitlin's Cozy MKIV Information] [Zeitlin's Cozy MKIV Logbook]
[Cozy MKIV Information]
Copyright © 2002, All Rights Reserved, Marc J. Zeitlin