This has been a really fun project that got started last winter. The airplanes owner, Luisa, is from Mexico. It is a Daytona Cub which was the early Smith Cub kit. It is a 180 hp wide body, extended wing with a very basic panel. Luisa weighs 90 pounds and even with lead shot in the aft baggage still couldn't get the tail down for a three point landing. The early Smith kits had the angle of incidence wrong on the tail, many were discovered and rectified prior to cover but unfortunately this one was not. Luisa called Thrustline Mark to see if his mod. would rectify her problem instead of cutting fabric and metal to modify the tail position. Anyone who knows Mark knows how anal he is about proper alignment and rigging of a Super Cub and he was not happy with just installing a Thrustline Kit. He measured some Smith kits and figured out how much the tail was off. He then figured out how much to change the wing to get the degree of differential angle of incidence between the wing and the tail. He then contacted Wayne Axleson and Jay Drozier at Turbine Cubs of Wyoming and had them manufacture some front spar fittings to kick the front of the wing up to get the wing to tail relationship correct. Luisa was game for all of this because she was tired of a nose heavy airplane. She had removed her Borer prop and installed a wood prop and flew with lead in the tail. She flies a lot in the mountains of Mexico at high elevations and wanted the airplane to perform well. She and Mark contacted me and wanted to know if I would be interested in installing the fittings. I thought they were crazy when they told me I could replace the fittings with the wings on the airplane but we tried it and it worked.
I removed all the wing root fairings, fuel tank covers and the inboard tanks. Looped a strap around the #1 compression strut hooked to a chain hoist in the ceiling while another strap was hooked to the front strut and tied to the hanger door to keep the wing from slipping backwards when I removed the front attach bolt. I removed all the bolts holding the fitting to the spar, Drilled and reamed the new wing attach hole in the spar web, installed the bushing and put the front bolt back on. The fairings fit with a little egging of the holes giving it a bit of a gull wing look. Rerigged the struts and cables and we were ready to fly however we got a snow storm and Luisa had to return to Mexico without flying the airplane. I flew it and unlike my first flight prior to incidence change I could fly the airplane down the runway with the tail on the runway where before I could not get the tail down until the mains were rolling and speed decreased. The airplane flew a lot better but still didn't feel like a Super Cub to me. I couldn't put my finger on it but it was different.
Mark had sent down a Thrustline kit and a Wayne Mackey leading edge slat kit was ordered from TCOW but we didn't want to install either one until Luisa was able to fly the airplane with just the incidence change. I picked the slat kit up from Jay and Wayne at New Holstein and upon returning home painted the slats and hangers. Luisa came in last Thursday evening from Mexico and flew the airplane a bit. Then on Friday morning she flew it some more. We installed the Thrustline mod and some test flights were done. Her comments were the control feel enhancement after installing the TL. It felt more stable to me and also I no longer trimmed the airplane. This airplane has the early overhead trim and your hand hits the overhead panel while trimming. I do not like trying to trim it but after installing the TL mod I only need to trim for cruise. Luisa flew it some more Saturday morning in cool air and was all smiles.
After Luisa was comfortable flying the TL mod. we started installing the slats. I couldn't believe how easy they were to install. Bolt the hangers to the slats, hold them up to the wing, a little tape to hold them and screw them through the leading edges. There are two flanges on each hanger. One side screws though the rib while the other side is into the leading edge skin. I got the stops installed so that the slat opens 2 7/8" but it was too late for a test flight. Early Sunday morning Luisa took off. Upon her return she thought the airplane was a lot more maneuverable but didn't think it landed any slower. I flew it and was in awe. With 50-60 gallons of gas, 35 lbs in the aft baggage and me at 150 lbs. it climbed like a homesick angel. I was intimidated at first thinking it might d something funny if one slat opened and the other stayed shut. I figured out it doesn't work that way. I went to altitude and flew at zero airspeed for 30 minutes making circles in a few hundred feet arcs. Slow flight with an exaggerated angle. It still flies when the ailerons don't work and you just slide side to side with the rudder. I slow flighted it down the runway at 27 mph with full control. I figured out that by doing a normal SC approach and then when I have my touchdown point made I pull the nose up and add a touch of power the airplanes seems to levitate and touch down tail first and stop. I kept adding to much power and the airplane would rise in this nose high attitude with full control until I let off the power and then it would come back down. I was totally amazed. I landed for the last time and taxied to the hanger. By this time Cathy had brought Lee to the hanger and he wanted to fly in the SC with slats. He got to land and take-off in a friends field and tell him all about slats.
After explaining to Luisa my technique we both figured out we have to relearn how to land this airplane at the slowest speed.
It is fun and all to land real slow at a real high angle of attack but the real benefit I see is the slow flight maneuverability. I was turning base to final with 2 notches of flaps at 40 mph indicated, prior to the mods the bottom would have been falling out and I would have been adding power, dropping the nose and sucking up seat cushion. We are still truly amazed. Removed the BLR VGs today and will install them 1" behind the slat per Wayne Mackey's instructions for further testing. Unfortunately Luisa is planning on returning to Mexico on Wed. and I won't get to play anymore for a while. Got me thinking seriously about an experimental SC with slats now.