I went to the Tripple Tree fly-in for the first time this year. I must say I had a blast. The grounds there are exceptionally beautiful, like being in aviation paradise. While I was taking pictures of RV's that were flying in, I noticed that there was a very pretty RV7A that was just parking. I ran over to it to take some pictures of it as the pilot was shutting down the engine. I wanted to get one last picture of the plane, but with the pilot next to it, so I asked if he minded if I took a picture of him and the plane. He smiled real big, and said sure and proceeded to climb out of the plane. As soon as he threw his leg over the side of the cockpit rail, I was completely shocked! He had one leg and the other was a prosthetic leg. I guess I didn't hide my shock very well when I took a double take on his leg. He laughed at me and said, "Pretty amazing, huh?"
I asked him how he flew with just one leg. He then invited me to the cockpit of his plane and showed me all the custom designs that he had created to allow him to fly safely and effectively. I was floored to say the least!!
The name of the pilot was Carl Bell, a super friendly man guy whom has taken some lemons that life has served him and turned them in to lemon meringue cream pie with whipped cream and a cherry on top! We talked for a good long time, and I took many pictures of his plane and handy work. He told me he had written an article about all the work he had done on his plane, and that it had been posted in several venues. He said that if I wanted to have it for
RV-Nation that he would gladly send it to me, which he did. The following is his article for all of us to read. I hope you enjoy his RV7A creative workmanship as much as I did, and if you are in need of this type of setup, hope this helps to make your aviation dreams a reality.
"In my younger years I always thought I would be a pilot, I loved model airplanes and graduated into radio controls in my teens. After a stint in Vietnam, it was back to the real world, getting an education and finding a job to support a new family. While doing this, I started pilot training earning my Private, Commercial, and Instrument ratings. I figured I could eventually get out of the high-tech computer industry and move on to the fun stuff of flying for a living. What I didn't realize was how little a rookie pilot got paid, especially compared to the computer industry, nor how long it really took to turn flying into a viable career. This didn't play well for a family with with our first baby in the hangar and accustomed to a reasonable cash flow.
I became successful in my computer career, but never lost my dream of building an airplane and flying again. I started building a Skybolt, a Sonerai, and a 2-seater of my own design, but my company moved me around and all these projects had to be sold before they were finished. Would I ever have an airplane or would life always get in the way? After many trips to Oshkosh and a trip to Oregon to see and fly the RV7, I made up my mind to get a Quickbuild and see it through, no matter what.
This time, something more drastic than a company move got in the way. While in my late forties, I was playing golf at my home course. A sudden storm developed and I ended up with a large tree on top of both me and my new golf cart on the 13th hole. Yeah, I know this seems like a tall tail, but it's the truth. The tree almost took me out, but some really great doctors brought me back from near death. They managed to save most of my body parts, all except for my left leg.
So, here I am, years later, with 2 million miles logged in airplanes. Unfortunately, they were all airplanes that said Delt, United, or US Airlines on the fuselage. No leg, no airplane of my own, and a few years from retirement. Crap! This is just not working out.
Not one to let a few inconveniences get me down, I went to the local FBO and hooked up with an experienced and patient flight instructor to see if I could fly Cherokees safely and reinstate my ratings. I became comfortable with my skills and the instructor signed me off on a flight test with an FAA examiner to get a SODA ( Statement of Demonstrated Ability) waiver on my medical. I passed after a pretty rigorous flight test, but I wasn't totally happy with my rudder braking authority using my prosthetic leg with is attached above the knee.
On top of this, my plan was to build (if you're counting, this is the 4th build attempt) an RV7A. My objective was to fly a high performance homebuilt as well as a fully abled person. To me, that meant full rudder authority for gentleman's aerobatics and crosswind landings and no compromises flying, braking or taxi operations. I was not going to take my wife Cheryl up or any passengers unless was positive my skills were not compromised. The plan was straight-forward; add differential hand brakes between the seats and a push-pull rudder that would allow me to fly with my good right leg.
Now that you have the background, let's look at the modifications I made to N947CB "Redhawk", my beloved handicapped facilitated RV7A.
The Handbrakes
Let's start with the modifications for the handbrakes. I wanted this design to be simple and also easily removable in case I needed to sell the plane. After all, I'm on the "back nine" and medicals are still required for your Private and Instrument tickets. I zeroed in on dual handbrakes between the seats leaving the toe brakes and rudder pedals per Van's plans. I knew from previous experience, and Van's preaching, that departing from the plans meant added time, complexity, and weight and introduced other bad or unknown factors. Still, I reasoned that adding two master cylinders, some extra brake lines and handles should be straight forward and get the job done.
Construction of the Handbrakes
I used the same Matco master cylinders as those in the kit, but with adjustable clevis ends (MCMC-4A). I consulted with Matco and they told me adding two more cylinders in line with the other four was not a problem, except perhaps for bleeding. They were also kind enough to send me the leverage design data so I could figure out the mechanical advantage required for the hand lever design. I constructed the finished system our of 2024-T4 x 1/4" aluminum angle and bar stock. I also added a .063 doubler with the 3/16" nut plates to the seat pans for strength and so I could easily remove them if need be for maintenance or removal. If anyone needs handbrakes, I would be happy to share my design and dimensions.
The Push-Pull Rudder System
I dreamed up a number of designs for the push/pull rudder. The simplest used pulleys and a cable between the left and right pedals. This design seemed prone to issues and would require a "U" turn in the cable. Then I saw an elegant design used for nose wheel steering on a GP-4 and reasoned it would give the push-pull that I needed. I would just drop out the nose wheel steering part of the linkage. After many revisions on the drafting board with the pedals shown in full deflection, I came up with a fairly simple design, using a bell crank under the front deck and two adjustable rods similar to the flap linkage.
Building the Push-Pull Rudder System
Modifying the rudder pedals during construction was easy. The basic design is two levers welded to the horizontal rudder pedal tubes, attached to a bearing bell crank mounted to the middle rib under the instrument panel. There are doublers in the panel rib similar to those used for the canopy support tube. As mentioned, two control rods attached from the bell crank from the left and right horizontal rudder pedal tubes levers. The adjustable control rods are also used for tensioning the cables. The last part of this design is a foot yoke that goes over the top of my right foot so I can pull the right rudder pedal moving the rudder left. The yoke is attached with two AN-3 bolts through welded bosses in the right rudder pedal tube. If you happen to be a right leg amputee you would mount the foot yoke on the left pedal. The neat part is I can remove the two bolts, the bell crank and push rods and the plane reverts to a standard RV.
Conclusions
The hand brake design works really well. I don't have the issues that some pilots have with riding the toe brakes and I can turn on a dime. In crosswind conditions it adds to controllability without excessive brake drag. The only change that might be useful for smaller/weaker pilots would be to add a little more mechanical advantage to reduce application force. Bleeding the brakes was not a problem, and after solving a couple leaking fittings, I was good to go. I also would recommend using a Matco parking brake for additional safety. I plan to add one during the first annual. The system wasn't cheap. It added almost $350 in cost and about 4 pounds in weight.
While the hand brake system scores a 9.5 out of 10, the push-pull rudder system only scores a 7 out of 10. Why? Well, it's that big rudder Van designed for the -7A. For taxi and crosswind landings up to 10 or 15 mph, it works well. For anything more than that, I do not have enough pull strength in my right leg to get full deflection. I still tend to use my left prosthetic leg on windy days to get more left rudder as needed, but for now I also carefully plan my trips and if the winds or weather exceeds my comfort zone, I don't fly. I am getting more skilled at flying in adverse conditions, but I am expanding the envelope carefully. Again, nothing is free and this revision added about $200 in cost and 4 pounds of weight, not to mention many additional hours in build time.
There are many pilots before me that have overcome serious handicaps, and they were a great inspiration to me. I remember an article about a paraplegic builder that converted his RV6 to all hand controls.....throttle, rudder, brakes and control stick. And a taildragger to boot - amazing! If he can do it, I can do it. My point is, if there is something getting in the way or your dream, just keep working towards it with determination and it will happen. Every day that I fly "Redhawk", I am truly amazed with the harmony and design of this beautiful plane. The only issue I have now is I can't get rid of this huge "grin" on my face. If you want to see more pictures of the build, they are at
www.mykitlog.com/carlbell ".
Truly inspirational to all of us to keep on reaching for our dreams, and never give up.
Keep on RV-N,
Buzz
RV-Nation
Then I brought the plane in for a major refurbishment. I changed the cowling out for a Sam James Holy Cowl, which was significantly lighter, and had the round air intake openings. Sam James, who is a friend of mine, told me he had done significant studied showing that round inlets provide less drag that rectangular inlets. I then installed a Sam James fiberglass plenum chamber. I really liked the plenum chamber, but I did have some over heating problems at first. The reason for the overheating was not the plenum chamber however, it was because there was too much leakage around the plenum. After fixing the leakage, the temps were constant around 180 degrees. 
