Here is the EAA Smilin’ Jack Chapter 866 President Les Boatright’s Panther LS SN083 N866BR First Flight in depth report. This write up is part of their EAA Chapter Monthly Newsletter. This Panther LS is powered by a Lycoming O-235 and a Sensenich propeller. The builders are Bob Rychel, Ed Brennan and Les Boatright from Titusville, FL.
A memorable event for our chapter this past month was the First Flight of the Panther kitplane project that Bob, Ed, and myself have been building since the beginning of the year. I know many of you have been following this project closely and I’m happy to report we had a nice maiden flight a couple weeks ago, and have flown the plane again since then. As I’m writing this, we have 2 flights and a little over two hours of flying time logged. I’ve written a more thorough First Flight Report separately down below.
The hangar doors slid open before first light on Saturday morning, September 16th, 2017. The stars were still twinkling overhead, indicating that the sky conditions this morning were clear. The local AWOS reported “wind calm” and “visibility 10 miles”. So far, there was nothing about the day that should keep an airworthy airplane from taking flight. This morning was the 246th calendar day since our three-man kitplane building partnership of Bob Rychel, Ed Brennan, and myself had started the construction and assembly of Panther aircraft Serial No. 083. Now, just over eight months and about 1600 combined man-hours later, all the rivets had been set, the paint was dry, all the wiring, plumbing and controls had been fabricated, installed and tested, the weight and balance was complete, and the myriad of FAA paperwork was in order and signed off. We had our airworthiness certificate issued a couple weeks earlier, and now the Panther was fueled and ready. There was nothing left to do but to go out and FLY this brand new flying machine!
The Panther waited patiently while I went through a thorough preflight inspection and then pushed her out into the first light of dawn. My two partners, Bob & Ed, were there to go over the test plan for the morning and to act as ground safety monitors. The three of us had gotten to this point as a team and as far as I was concerned, we were doing the flight test together as a team, even if only one of us would actually be in the airplane. Bob and Ed both were depending on me to do a good job on the First Flight, and I had prepared about as much as I could. There’s no way to get “checked out” in a single place airplane except to fly in other similar types of airplanes that have similar performance. So, in the weeks and months leading up to this morning’s test flight, I had logged several hours and as many as 50 tailwheel landings with CFI and Chapter 866 newsletter editor extraordinaire Larry Gilbert. We practiced a lot of the same things in his Citabria that I would be doing in the Panther on the first flight, including engine out contingencies. In the days prior to the Panther’s first flight, I had taken it out and performed about 25 fast passes down the runway. The flights in the Citabria helped me to fine tune my landings, to practice slow flight, and to become really familiar with all the runway options and off-airport options that were available around Arthur Dunn Airpark in case our perfectly good engine decided to stop at a perfectly inappropriate time. The fast taxi tests gave me a good feel for how the Panther would handle on the runway, how quickly it would accelerate, how responsive the rudder, brakes, and ground steering would be, and also allowed me to verify that the airspeed indicator was working correctly before I was committed to actually flying. The taxi testing was also a good way to develop the mental and procedural habits of running through the pre-take off checklist each time, and to become really familiar with the location and operation of every control and switch in the cockpit. All of these little steps taken together were big confidence builders.
From the outset of the project, Bob, Ed, and I had the goal of building an airplane that would be simple, quick to build, fun, sporty, economical to operate, and easy to fly. After casually studying the Panther kit development over at Sun-N-Fun for 2 or 3 years, and then joking with each other about building one, the three of us basically decided to put-up or shut-up! We all felt that the Panther should be an enjoyable build project, a relatively fast build, something that was squarely within our skill sets, something that would be affordable by way of sharing the cost 3-ways, and by all accounts it should be a wonderful little airplane when finished. Well, on this 16th day of September, we would find out if the project would fulfill all of those lofty expectations.
Many of the Chapter 866 folks have stopped by our project over the course of the eight month build and have commented on how quickly we were making progress with the project. In my opinion, much of that progress is due to the quality and completeness of the kit. The kit had several features that made it easy to build, including:
- Matched-hole tooling technology in many of the structural components
- A large number of the parts were precisely machined or LASER cut to final dimensions by CNC tooling, making the kit manufacturing more of an Assembly than Fabrication operation.
- Most aluminum parts in the kit were already pre-piloted to allow for easy match-drilling
- A relatively low number of total parts count for a plane like this one
- A very clever steel cage design in the fuselage with pre-located attachment points all major structural items, like landing gear, wings, engine mount, and canopy.
- And a large volume of detailed instructions and construction photos in the builder’s manual.
However, our rapid progress was also due to our 3-man team. We quickly realized that each of us brought something to the project that the other two could learn from, and I know that we all learned new building techniques from each other in the process. By having 3 people working together, we had immediate help when we ran into a question and needed to consult with another builder on a technical issue. So it was like having two EAA technical counselors with you all the time. And yes, there were a coupla times we disagreed on something, but we never disagreed on the goal of building a safe airplane. We also had the advantage of more hands on the project, so some of our early work tasks were “Divided and Conquered” by each of us separately. This allowed multiple airframe components to be “In Progress” at the same time, at least early on as the piles of parts still outnumbered the completed assemblies. Plus, all three of us had prior kit-building experience on RV’s and Zeniths, with this being the THIRD airplane completed for Bob! The Panther project fit very nicely into our collective skill-set. We all liked working with sheet metal and rivets. Given our past building experiences, we also made some key decisions at the very outset that made the project go together more quickly, without sacrificing anything on quality or safety. For example, we purchased the pre-assembled fuel tanks from the Panther factory, as well as the factory pre-bonded canopy skirt. Those two areas both seemed like very good places to trade money for time, and help us avoid the potential for making mistakes on two critical assemblies.
For our powerplant, we decided to purchase a good used Lycoming O-235 aircraft engine to keep the engine installation as straightforward as possible. Plus there’s tons of information available for those engines in case we needed to find help. We also decided to use protruding head rivets for all exterior airframe skins instead of the flush-head rivets used on the factory prototype. While the flush rivets give the factory plane a very nice look, our decision to use protruding heads undoubtedly saved us 100 hours or more of dimpling and countersinking. Our goal of a speedy build was more important than the goal of a super speedy airplane. We figured that at airspeeds below about 150 MPH, the drag penalty of protruding rivets would be pretty minimal anyway. We also decided to try our best to keep the airplane simple. We went with a Simple, Daytime, VFR only instrument panel. By not installing any exterior lighting, we saved time with wiring, and saved cost and weight as well. Hey, if it’s not on the airplane, then it weighs nothing, costs nothing, and cannot fail! By painting the airframe all ONE single color (Red), we saved all the extra time spent laying out paint schemes, and masking and sanding that would’ve been spent on a more complicated, multicolored scheme. We could always add decals later if we thought the single color scheme was too boring.
We believe most of these decisions turned out to be good ones. We were able to make quick progress on the airframe. In fact, much of the airframe structure was complete by about 3 months into the project, or around the time we took a break to go to Sun-N-Fun. This is also where that old saw about being “90% done, with 90% left to go” comes into play. We could see that most of the airframe was together after around 600-700 hours combined hours into the build, BUT we still had a lot to do to finish. Things like wiring, plumbing, engine systems, baffling, cowling, spinner, canopy latches, rigging, systems testing, and so on, just take time. Some of the work on the Engine took a little longer than we expected because the firewall is relatively small and requires that you plan very carefully how you use the firewall real estate for mounting things like batteries, solenoids, and gascolators. The Lycoming engine also sits pretty close to the firewall on the Panther, so you begin to run out of volume to work in that area pretty quickly.
As we progressed toward that last “90%” of the build, we developed an extensive list of tasks that we still had left to do. We worked our way through each one of them until eventually we were ready to test the engine at the end of June. The FAA says that building an experimental airplane is about “Recreation and Education”. Well, we must have learned something right about timing and synchronizing magnetos, because, much to our delight, the engine started right up on day #168 into our build! I admit I didn’t sleep much later that night thinking about how cool it was that we were already running and testing the engine!
We continued working through our punch list in July, and started preparing all the paperwork for the FAA. On August 29th, we hosted the nice folks from the FAA, and had a pleasant and uneventful airworthiness inspection. They were friendly, punctual, well-prepared, and professional. Our inspection lasted about three hours and the two inspectors found about a half-dozen non-critical items to correct. Most of their findings related to safety wire, fastener thread-protrusion, and chaffing protection. All items were easily addressed the following Saturday, and with the Panther now in its full up flight configuration, we were good to continue more ground confidence testing.
During the two weeks or so between receiving our airworthiness certificate from the FAA and the day of the First Flight, I took the Panther out to the runway several times for taxi testing as discussed previously. Again, I believe this testing was extremely valuable in gaining a good feel for the Panther’s responsiveness on the ground and developing my ability to positively control the airplane without having a tendency to over-control. By the morning of the first flight, the pre-flight procedure had become a familiar ritual. It was just like I had practiced for my taxi testing, except today, I would not be pulling the power back to idle after getting the tail off the ground like I had done before. I would keep accelerating until airborne, then climb for altitude, and orbit the airport.
The test plan for the first flight was to climb directly over the airport to 4,000 feet, keeping the airfield within easy gliding range at all times, so that the option to return at any time would always be available if needed. The objectives of the flight were really simple, verify engine reliability, explore the basic handling characteristics, do some 360 turns left and right, do some slow flight, then make a few pre-planned practice landing approaches back down in the traffic pattern, be safe in everything, and then land.
“Always leave yourself a way out.” Chuck Yeager
The take-off was uneventful and before I knew it, the Panther was climbing away as if it had done it a thousand times before. “Well, I guess we have an airplane now!”, was the thought that flashed through my mind for a split second. During the climb out, I stayed close to the airport, observed the engine and flight instruments closely, looked and listened for problems, and reported my status down to Eddie, who was acting as the ground safety monitor. Once at my target altitude, I leveled off, and ONLY THEN did I make the first power reduction to more of a low cruise power setting at around 1900 RPM.
At that point, if everything had gone OK, I had planned to take a few brief minutes just to relax, enjoy the view, and take in the moment. That may seem odd to some folks, but if you’re an ordinary human, then it’s natural to have a little nervousness when doing something like a first flight on a new, unproven airframe. I tried to use any pre-flight nervousness to my advantage, by allowing it to keep me mentally sharp and stay focused on the most important things.
“Stay up on the edge of your seat.” Scott Crossfield, Test Pilot
Everything went OK, the engine oil pressure and temperature were well within the parameters for our Lycoming O-235 and they indicated no adverse trends. Controlling the airplane and making it go where I wanted it to go was easy and predictable. I quickly found that I could cruise along easily at around 95 to 105 knots at around 1900 RPM. Not trying to find out how fast it will go today, just fly it safely and land. I gently wagged the rudder, rocked the wings, and pitched the elevator up and down a few times to see how much response the plane had for a given control displacement or input. Control was very positive and the airplane would stay right where I put it. I found I was able to control pitch and roll with light fingertip pressure on the stick, and I found the trim lever to have a very positive effect when repositioned. It was no trouble at all to trim the plane for level flight at a given power setting.
About halfway through the flight, I discovered that I was maintaining constant right rudder input to keep the ball centered in the inclinometer. The weight and pressure of my feet on the pedals had kept me from me noticing that I was holding a little constant right rudder pressure. I was just instinctively doing what I had to do to keep the ball centered. I removed both feet from the pedals briefly and the nose swung to the left, so I believe we’ll need to add a fixed rudder trim tab, but a few more flights will confirm that for sure.
Part of the test plan was to simply do 360 degree turns left & right at 10, 20, & 30 degrees of bank angle. I found these to be a good way to get a feel for the plane, and by the third or fourth 360 turn, I felt very comfortable being able to set and hold a bank angle and also maintain the desired altitude.
The next goal was slow flight, and to determine a good approach speed for landing. Prior to the flight, I had been concerned that just arbitrarily picking a landing approach speed based on other Panther flight reports, might not be wise IF for example our airspeed indication was reading significantly off. I reduced power, held the nose up enough to let the airspeed decelerate slowly, re-trimmed for airspeed and flew around for a few minutes at about 55 knots and monitored engine temps and the pitch forces on the stick.
Next, I wanted to see where the Panther would stall. As I cleared the area, I continued to decelerate the airplane slowly down thru 46 knots and began to feel the stick get a little “mushy”. I found that the nose wanted to dip at around 44, or 43 knots indicated airspeed with the flaps up, then at about 41 knots with 10 degrees of flaps, and at 39 knots with 20 degrees of flaps. It turned out to be fairly easy to hold the nose steady in a shallow gliding descent and let the airspeed decay until the nose dipped, then it would gain a knot or two and start to fly again, but with a little back pressure, the nose would dip again. There was a spot where I could flirt in and out of the early stage of a stall, letting the nose bob down and then up slightly, while holding constant pressure on the stick and being in a sort of gentle falling leaf attitude. This condition was repeatable at the two flap settings I tried, and as long as the ball stayed centered, there was no tendency for one wing to drop off. Since it was a first flight, I did not attempt anything more than that. My goal was to simply find the indicated speed where the plane wanted to depart controlled flight, and then add the 1.3 or 1.4 margin to know what the best traffic pattern speeds should be.
“Go from the known to the unknown -slowly!” Chris Wheal, Military Test Pilot
After recovering from stalls and slow flight, I ran through the pre-landing checklist and tried a simulated traffic pattern at altitude. Next I switched tanks in flight while still high enough to recover from an engine stoppage, and I flew for a couple minutes to make sure I was getting good steady fuel flow from the other wing tank. At this point, I was ready to descend to the traffic pattern, where I made several pre-planned landing approaches. By this time, I had been flying for almost an hour, the engine was running smooth and showing good oil pressure and temp, giving confidence that there was nothing amiss with the powerplant. I did the low approaches so I could judge the traffic pattern sight pictures from the Panther. All my recent time had been in a high wing Citabria, and I knew the Panther would feel a little different. I also wanted to learn how the airplane descended in the pattern at a couple different power settings, and practice doing a couple go-arounds in case I needed to do that during an actual landing attempt. That turned out to be a wise move. After 2 or 3 circuits, I realized that it was easy to let the Panther build up a little extra airspeed if you did not get it under control early, and the extra drag from using the flaps was helpful in establishing a stabilized approach. One of my old instructors used to say that the key to a good landing is THREE things: 1. Proper airspeed control, 2. Fly a Stabilized Approach, and 3. Nobody knows what the third thing is!
At about the 4th low approach, I had gotten things dialed in pretty nicely. It felt nice turning base-to-final, I had pitched for the airspeed I wanted at around 60 knots on final, had a stabilized approach, had my aim point picked, a nice rate of descent, was mentally ready for a go-around, but had the runway made and everything was looking really good. “This is it.” I said to myself, “I should be able to land this one right where I want”. As I glided in over the threshold and started to round out, I felt (and saw) the manual flap handle mounted to the left of my seat pop down from 20 to 10 degrees. The stick force and pitch attitude changed slightly, and at less than 30 feet above the ground I had about a second or two to chase it and re-establish the pitch attitude for landing, OR I could go-around. It was a super easy decision to apply power and go-around. Smartest maneuver in any pilot’s bag of tricks, in my opinion. Well, I was really glad I’d practiced the maneuver a few minutes before during the low approaches. It turns out that I did not get the manual flap handle fully locked into its 20 degree detent when I put the flaps down. Lesson Learned, always give the flap handle a little jiggle after repositioning it. This was really the only unexpected or tense moment I had during the whole 1.5 hour flight, and it didn’t last more than 2 seconds.
By the time I was back down to pattern altitude, a few of the usual Saturday morning airport crowd had arrived and Ben had taken off from the turf runway in his trusty Pietenpol. I had originally planned to land on the grass because it tends to be more forgiving and I had done a lot of those with Larry in the Citabria. However, Ben advised over the radio that it was still very wet from the recent deluge by Hurricane Irma. Based on Ben’s report, and not wanting to earn a seaplane rating on my first Panther flight, I repositioned for a landing on the pavement. This time the flap handle was locked for sure, I settled down in a 3-point attitude, had a short little bounce and rolled out to the end. That was it, the first flight was in the history books! I guess I’d say it was one of the biggest “uneventful” events of my life! It was kinda like my first solo all over again, only better.
After it was over, I spent a lot of time reflecting on the flight, thinking about how everything went and what I could learn from it. I found myself feeling somewhat amazed at how smoothly it all went, and how closely the actual flight had followed with my mental planning and expectations.
“Plan the flight, fly the Plan.” Sign on the wall at Naval Test Pilot School, Patuxent River, MD
In preparation for the first flight, I read through the FAA Advisory Circular on Flight Testing your Homebuilt Aircraft, AC90-89B. I read this several times, and I would HIGHLY encourage anyone to read it thoroughly before doing a first flight.
Besides actually flying with Larry in the Citabria, another first flight prep activity I did was watching a number of online videos about tailwheel flying, and getting checked out in new airplanes. Even though I’ve had the tailwheel endorsement for many years, I think you can never learn too much about the sport of flying. I found that being able to “ride along” (via video) and observe another pilot and listen to the banter with the instructor is a terrific learning tool. With this technique, there’s no pressure on you to do the flying, so you have time (call it mental bandwidth if you will) to keenly observe little nuances about the flight that you might have missed otherwise. Plus you can replay the footage as often as you want to pick out a specific detail about the flight or a landing. There are some really terrific videos about getting a tailwheel checkout in a Super Cub on the FlightChops Youtube channel. While this video learning technique may not be for everyone, and cannot be “logged” as instruction, I still found it very helpful.
Finally, using the FAA Advisory Circular as a guide, I wrote out a detailed script, or a flight test plan for the first flight in the Panther. It was pretty informal, but covered a little over 4 pages, where I outlined a prioritized list of test objectives, and detailed how I expected to fly the mission. The script always kept the option open to “knock it off” at any time and return to the airport and land if something went off-script or didn’t feel right. So that’s another technique I would suggest. The simple act of writing out a test plan script, then re-reading it, and reediting it over and over several times thru is a way that forces you to mentally fly every element of the flight in the comfort of your office chair before actually flying it for real in the airplane. Some folks call this technique “visualization”. For me, it was more about establishing and practicing all the mental activities needed to fly the flight safely, make good decisions, practice “what-if” scenarios, and be able to take good notes about what the airplane was doing. I printed out the script to have in the cockpit and to share with Eddie & Bob as they monitored on the ground, but it turns out I never looked at it in flight. I didn’t have to because I’d already been through it so many times in my head that the printed copy was redundant.
We painted the Panther Red because it looks good, and because red covers nicely and is easy to spray. Once the fuselage was painted, we occasionally called it our “Little Red Wagon” just as a joke. As a pure coincidence, we learned that the Radio Flyer wagon company celebrated 100 years of being in business back in July as we were finishing up our project. Some of their history can be found here: http://www.radioflyer.com/celebration. They also produced a wonderful, award-winning Short-Film called “Taking Flight” that you might enjoy watching. https://www.youtube.com/watch?v=Gj6V-xZgtlQ
In just 8 months, the Panther has become the fulfillment of our imagination and enabled our dreams to Take Flight. I hope that flying makes you feel like a kid again everytime you take off!
With sincere Thanks to my friends and awesome building partners, Bob and Eddie, for building such a great airplane and for trusting me to fly it safely! I look forward to seeing your faces when you taxi in after your first flights!
“Radio Flyer Test Pilot”