OK, onto the next problem, mounting the wingtip missile rails....
There are a few issues with the missile rails as provided in the kit especially when compared to the full scale rails. Refer to photo 1 which provides a side view comparison. The issues are:
1) They are too short by 1-1/8". For the correct scale of the kit, the model rails should be 26.9" long. They are also too thick and chunky-looking. The full size Gripen is sleek and elegant. The kit rails make it look like you used an axe to hack a rail out of at 2 x 2 from Home Depot and mounted it on your plane.
2) They are hideously out of scale. The molded in features are in the wrong places, and the angles on the ends are all wrong
Photo 1 - comparison of full scale and kit missile rails
3) They are pre-drilled for 6mm mounting bolts. The kit photos show the rails being installed with metal bolts. Are you kidding me, a 6mm grade 5 bolt shears at just over 2000 lbs of force and fails in tension at about 3250 lbs. Needless to say, if you snag a wingtip rail on take-off or landing (as Gripens are occasionally known to do) you can pretty much count on ripping your wing off rather than shearing a bolt.
4) The molded fairing to blend into the fuselage puts the rails at the wrong angle. The washout angle is wrong. On the full scale, the wingtip missile rails have -1.85 degrees of washout compared to the nice straight dorsal line of the fuselage. The model has them at about -0.5 degrees. Now you might be saying only 1.35 degrees of difference, come on Jim, nobody would notice that. Bullshirt....the difference is obvious because the rails are so long and have these nice cream yellow sensors at either end to accentuate things, and the angle can easily be compared to the angle of the dorsal deck or the ground.
See for yourself. Can you see the difference?
Photo 2 - Side view photo missile rail at correct angle
Photo 3 - Gripen with missile rail at kit angle.
Alright, so the question is what to do about it. Well, if I wanted a scale missile rail, I wouldn't start with the kit rail. It looks like I need to add missile rails to the list of items to be molded. However, I really do need to get this plane in the air so I can get some flight practice and develop a routine. The scale rails can literally get bolted on a minute or two before taking the plane to the static table at Top Gun. So....I'll fly with these initially, and will replace them later.
To mount the kit rails, forget all about the 6mm holes. Apart from being too big, it will be tough to find 6mm threaded inserts to install in the wing. At the local hobby shop or Ace Hardware, you can find threaded inserts for 10-32, 8-32, and 6-32 threads. Nylon bolts would be a better choice for holding on the wingtip. The tensile and shear strength of nylon bolts are:
10-32: Tensile 165 lbs, shear 120 lbs
8-32: Tensile 108 lbs, shear 82 lbs
6-32: Tensile 69 lbs, shear 43 lbs
Now, considering that two bolts are used to hold on the rails (which weigh 4-3/8 oz or .27 lbs) we can easily go with 6-32 nylon bolts to hold on the rails. That might save your wing one day.
Regards,
Jim