wing span 143 cm 56 in
wing area 39,5 sq dm 612 sq in
tailplane 25 % of wing  
weight of wing wood 450 , finished 650 gramm 23 oz
weight of tailplane 66 gr, fin 106 gr 3,7 oz
weight of fuselage 294 gr 10,3 oz
airfoil thickness root 18 %  
airfoil thickness tip 19 %  
final weight 1600 gr 56 oz
engine OS 46 LA own venturi
propeller Eather 3 blade 11 x 4 1/4
tank metal Uniflo 5,4 oz
venturi ( NVA through ) 6,6 mm 2559
fuel 10 nitro 10 castor 10 synth
lines SIG 015 65 ft
                                           
                 
     
  In 2001 I needed an airplane which would allow me to compete in Classic as well as in PA at the US Nationals. Since Old Time and Classic is not so popular in Germany and this airplane should also be used in FAI contests over here, I was looking for a capable design. Judging from the plans the Grondal seemed to fulfill this role - and it is a pretty airplane, too.
As it turned out my expectations were even exceeded. Considering its age the Grondal is a very fine flyer. I don’t say it is my best airplane but it’s the one I like best. This is difficult to describe - somehow it’s the easiest to fly; it seems I need less practice flights to get used to the airplane after I have flown other ones for a while. So when in search of a new 46 size model, I used some of the features of the Grondal for the new design. That’s how my “Serenade” design (the forerunner of the “Blue Lady” ) came into being.
                         
This proved to be a success. Alas it didn’t live very long - hitting the sun in the upper right corner of an inside square manoeuvre will strike you blind for longer than the following dive! So another airplane was needed. Because I was extremely satisfied with this design I chose to build it again with some subtle modifications.        
In my opinion there are several features of the Grondal airplane which make it a good design. I’m still convinced that the elliptical wing planform is the most efficient shape for a wing. But we all know that constructing such a wing is a nightmare. Oh yes, I did read the construction article by Joe Adamusco, and I have studied it very carefully. However - knowing my building skills kept me from daring an elliptical adventure. After all a trapezoid wing with well rounded tips comes very close in aerodynamics as well as in aesthetics.
 
The Grondal configuration has a very deep flap chord at the wing root and very narrow flaps at the tip. In fact there’s no flap at all at the wing tip. This makes for a higher taper ratio than average because the wing tip chord is smaller. Combined with NO flap at the wing tip this should somewhat reduce lift - and thus drag at the extreme tip. As a result of this the drag and vortex at the tip should be less in tight corners. Also if gusts hit our airplane far off the Center of Gravity ( = at the wing tip), there is less area = less lift = less drag. This should make the airplane more stable around the longitudinal axis. What the wing lacks in area near the wing tip it makes up in area close to CG (with the increased flap chord there). If gusts will induce any forces there, the moment arm (to CG) is short and cannot cause strong rolling moments.
 
Oh well, this is my opinion. I’m sure some experts will have their hairs stand on end now. However this just might be the reason for the special flying characteristics of the Grondal design. I’d really like to hear any comments about this. Anyway I had enough reasons to include these design features into my design. Apart from this such a wing outline is not seen very often - AND it is a beautiful shape, too.    
Since many years all my airplanes are fully detachable. That way the parts are easier to build, easier to handle, and easier to transport (in a box). The parts are fuselage, wing (one piece), tailplane, and fin. I reckon about 1 ½ or 2 additional ounces of weight for this "take apart" configuration. Usually my airplanes are not very light. “Blue Lady” came out at 1590 Gramm = 56 oz. Sorry - I really don’t know how I did this!
           
       
   
For decades I have used automotive lacquer spray cans for the color layout, of course finished with a final high quality auto two part lacquer clear coat. This time I had extreme problems with the spray lacquer. The manufacturers seem to have changed the product. BE WARNED !!! Always test lacquers before you use them. The name “Blue Lady” and the abstracted rose motivs are decals, drawn by hand, scanned in, enhanced with a photo software, and printed on decal paper.  
                   
I’m using an OS LA 46, a tube muffler handmade by a friend, and I’m fully satisfied with the performance and running characteristic of this engine. If I were a world top class pilot I surely would use one of the premium engines, but I don’t belong to this elite group. There are people around who really have to be careful with spending their pennies. So I wanted to prove that you really can have decent success with this simple (and cheap) engine. Propeller is a Brian Eather 3 blade carbon 11 diameter bent to 4 1/8 pitch. I use a metal Uniflow tank at about 165 ccm ( 5,8 oz ) for 10% Nitro 10 castor 10 synth fuel.
                                 
     
                                 
               
       

The name of this airplane? Oh, I just like this song.

Clicking on the little rose button will open a page where the process of developping the paint layout is explained in detail.