Spin Testing

CAUTION: Do not attempt spins unless properly trained or accompanied by an instructor experienced in proper spin recovery.

I have been planning for some time to do a complete spin testing program for the Bearhawk.  To my knowledge this has not been done other than Bob Barrows doing a couple of one turn spins.  For this testing, I decided to seek out out someone much better qualified than I am to help me during this program.  Lee Taylor is one of the members of my EAA chapter and does unusual attitude recovery and aerobatics training in his Christian Eagle, tailwheel endorsements in his Cessna 140 and has been the test pilot in several homebuilt airplanes for others.  Lee has nearly 40 years of instructing experience, was jet fighter crew chief for the air force, has been super sonic a couple of times, flew huey and cobra helicopters during vietnam and was a forestry air attack pilot in California.  Lee has flown a wide variety of aircraft and knows his stuff.

Lee and I discussed our plan and came up with what we believe will be a thorough, but safe way to fully explore the spin characteristics of the Bearhawk.   As a bonus for me, I'll be learning a bunch from Lee as we proceed and will hopefully be a better, safer pilot for it.

The Plan

Safety first.  Lee has a spin test drag chute that will be tied to the tailwheel mount and carried in the cockpit with us.  If, at any time we can't recover from a spin (i.e. a flat spin situation), the chute, which is small enough to allow the airplane to still fly, will be deployed, and hopefully will slow the spin enough to get air across the tail enough to recover.  Additionally , as a last resort, we will both be wearing chutes. The testing will be conducted from a safe altitude of 8,000 to 10,000 feet AGL.

The plan is to use the old "sneak up on it" approach.  This program will take several weeks or months. We will start the program with a forward CG, and light weight. Starting with some initial cross controlled stalls with immediate recovery, then progressing into a 1/4 turn and 1/2 turn spins.  If the airplane recovers nicely from those, we will progressively add more turns, adding about 1/2 turn at a time, until we are doing 7 to 8 turn spins.

If the airplane is stable and fully recoverable with the forward CG and light weight with 7 to 8 turn spins, we will start adding some weight to the back seat and baggage compartment, a little at a time, spin testing at each weight before moving up to heavier weight and more aft CG .  The weight will be added and CG location will be moved aft a little at a time until we are finally at full gross and maximum aft CG.

We both agreed that if at any point during the program, either of us feel uncomfortable, we will stop right there and discontinue it. If the airplane at any point feels like its going to not recover easily, we will stop right there and I will note the max weight and CG for spins in the POH and placard the instrument panel with the same.

First Testing Flight - May 29, 2009
Lee and I went up for the first time today. Remember, the goal here is to make me a better pilot, and to spin test the Bearhawk at the same time.   For this first flight, Lee wanted to spend some time getting to know me and the Bearhawk so this first flight together was mostly instructional, however we did get to do a couple of initial 1/2 to 1 turn spins and recoveries.

Lee let me do most of the flying and we spent some time just getting to know the Bearhawk better than I ever did during my flight testing.   We did several stalls both power off and full power departure stalls. We did steep turns with Lee insisting on accuracy as well he should.  At one point Lee said, "OK - the standard FAA stalls are all well and good, but they don't really teach you about the kinds of stall/spin situations people get into and get killed". Lee then pulled out one of the two rolls of toilet paper that he brought along and asked me if I had have ever done ribbon cutting?  "No, can't say that I have".  Basically the exercise involves dropping the roll of toilet paper out of the airplane at about 4500 feet AGL and then aggressively chasing it as it falls trying to cut it with your wing as many times as you can before it reaches the safety altitude of 2500 AGL. At that point the exercise stops. If you do it aggressively enough, you will eventually get so wrapped in trying to catch that ribbon that you will stall the airplane in a steep bank and maybe even a bit cross controlled. At that point you recover instantly using opposite rudder and forward stick, before entering a full spin.

OK - I'm game - lets do it.  So we started at 4500 feet and picked out a fixed landmark to drop the toilet paper roll over, that way I'd have a chance of finding it again. This is a low speed maneuver so you can't over stress the airplane, max RPM is 2000 and the speed is around 90 MPH.  So I picked a train trestle bridge and when we were over it, Lee had me slow the plane down to just above the stall, he opened window and said "ready?"  "Yup" says I and he threw it out.  Hard right turn to about 90 degrees, then immediate hard left 270 degrees and I was back over the train trestle and there was the streamer above me and to the right, I pulled up hard and turned right headed for it, just missed it, hard left turn 90 degrees and hard right 270 back to the trestle and there was the streamer again higher than me, I pulled up hard and turned toward it - Damn, just missed it again. By this time I wasn't even looking at the horizon, I would imagine I was getting pretty steep in these turns as kept trying to whip this airplane around and back to the darn toilet paper roll slowly streaming downward. I got so wrapped up in it that at one point I felt something that I hadn't ever felt before, vertigo. Wow, what a rush!

Ok with all of that out of the way Lee looked over at me covered in sweat but a big grin and said we better call it a day, you look like you've had enough.  I said "no, let's keep going".  I was having way too much fun to stop now.  Lee agreed and instructed me to climb on up to 6500 ft AGL do some cross controlled stalls.  He had me start by just putting the ball about 1/2 ball off center and doing a power-off stall.  I did it and the Bearhawk just sat there buffeting, no wing drop off as expected.  He that had me try it with one full ball of deflection - again, the Bearhawk just sat there, wings level, buffeting in the stall as I held the stick full back.  Lee then took the airplane and tried the same thing, this time holding full right rudder and hold the wings level with the ailerons and the stick fully back, the Bearhawk just sat there buffeting but staying level with no wing drop off.  At this point we should have been spinning like crazy!

Lee was totally amazed.  In over 40 years of flying all kinds of airplanes, he had never seen one that that was so controllable in the stall that you could actually hold full rudder and still keep the wings level with aileron.

So we decided to see what it would do in a spin.  Lee went ahead and took it and this time just as we started entering the pre-stall buffet, he pulled back abruptly on the stick and stomped hard left rudder, and the Bearhawk reluctantly dropped it's left wing and finally after about a 1/2 turn entered a fairly steep nose down spin. Lee applied right rudder after1 turn and relaxed back pressure, and the plane immediately recovered. He tried a another this time leaving just a touch of power in.  Here is the video I shot of these two initial spins.  You can hear Lee describing his control inputs for the camera. (Note:  This file is 61mb.  It's best to right mouse click the link and save it to your desktop, then play it from there):


Lee asked me if I wanted to try a couple of spins and I said " Heck yea!"  So I handed Lee the camera and he video taped me doing a spin. Of course my recovery wasn't quite as polished as Lee's and I didn't pull the nose up quickly enough after breaking the stall. Because of my slight delay, the airspeed had climbed up to 160 MPH in that short window where you hear Lee saying repeatedly "pull the nose up, pull the nose up, pull the nose up"  I can see where a person could get themselves in trouble real quick without an experienced instructor along.  Here is the video Lee shot of my spin (this one is about 30mb):


Lee sent me a write -up of his initial impressions of the Bearhawk. Coming from a man of his experience level, I am once again reminded that I picked the correct airplane to build. I'll let you read it for yourself. Here is Lee's initial assessment of the Bearhawk:


What a great flying day I had with my Bearhawk.  This such a great airplane!  This spin testing program will continue forward over the next few weeks/months and I will continue to video tape and show the progress.

Click here to go to Spin Testing page 2