I would like to know from those that have tried. Due to the banana boat the fire wall and longerons are not perpendicular. If I use the smart level and use the firewall as my main reference what will it do to the flight stance of the plane? >Steven Phillabaum +++++++++++++++++++++++++++++++++++++++++++++++++++++++++
This post is long so if you're not interested, hit delete now........... You will get as many opinions on this as there are builders. All will claim to be easy and accurate. Without saying my process is the only way to go, I'll let you decide. It worked for me and my KR flys without any fixed trim tabs and both aileron trail edges matching the wing trail edge. I attribute a very, very, very slight right wing heavy condition at cruise in my KR to me getting the trail edge rib on one side of the center section wrong. That can be eliminated by using the "Langford" method on the ribs. This process will work with either wing and whatever incidence you decide to go with. Just mark your ribs accordingly. Consider the important points ( I think ) of engine thrust line, wing incidence, and horz stab incidence to having a nice flying KR. My opinion is that the fuselage being off by a degree or so is much less critical than these items. I recommend using the firewall to level. It won't get crowded until much later in the building process and then you can use a short ( 6 inch ) level somewhere on the firewall to set the fuselage to level for W&B. Top or bottom of the firewall will do with only 3 inches or so of the level on the firewall. Do yourself a favor. Buy a "SmartLevel" (digital level ) now as you can use it to build/rig your KR and set control surface deflection later in the process. As Mark suggested, a good bubble level can be very accurate. I used two bubble levels to set up my KR and found it to be within 1/10 of one degee when checking later with the digital level. I started this process after I had my wing attach fittings installed on the spar with dihedral set on the work table. You then remove one set of fittings to install the spar as suggested in the plans. A complete "dry fit" run of this process before any epoxy is mixed will insure no surprises later. I'm speaking of a dry run of the center section only here, that being the forward spar, ribs, and rear spar. Start by leveling the fuselage using the firewall and place a level "across" the top longerons to level side to side. Insert the forward spar and level side to side and check distance from tip to tip to the tail for 90 degrees to the centerline of fuselage and spar is parallel to firewall (vertical). When you're satisified, glue the forward spar in place. Determine what wing incidence you want, draw all markings on the 48" ribs (cord line, spars ) and cut the 48" ribs using the "Langford method " with the "humps" at the spar locations. Cut out the spar holes and mount the ribs on the center section spar. Double check the incidence (using cord line and SmartLevel) and glue the ribs in place. If you have any twist in your forward spar (as I did) you can adjust your ribs using the digital level and cord line to compensate. Now use the rear spar cutouts to locate the rear spar and glue in place. Make sure you remove the "humps" on the ribs before sanding the wings! :-) Setting the horizontal stab is a matter of leveling the fuselage again (using the firewall) and place a SmartLevel across the horz stab spars, set the incidence you want, and glue in place. I set mine to level using a bubble level and probably should have been set to 1/2 to 3/4 degee down using a digital level. I'm using the RAF48 set to 3.5 degrees, 3 degree washout, with a 24 inch fuselage stretch. Go to Langford's sit to get an indepth read on this subject. I build my outer wing panels one at a time and that worked out also using the "SmartLevel". Level the fuselage (firewall) and attach the outer forward spar. Attach the 36" rib so it will pivot on the spar such as a nail through the rib to the end of the spar. Use the digital level and cord line on the rib to set the incidence you want with washout, jig and attach the rear spar, and start building. If each step in this process is done correctly, you will end up with a perfectly rigged KR. No math, no water levels, who cares about the banana boat, etc. I was able to build/rig my entire project as a one man operation. The only help I used was to cut/taper the outer spar caps and that probably could have been done solo also. Larry Flesner - 164 hours and still grinnin'
