Tim,

before commenting I'd just like to say that if any of these "other" Tipo builds (including my own) are not appreciated by you, please let us know. In my threads, I encourage exchange particularly if they are related to other builds of the same model but others may prefer to keep their thread more focused and dedicated to that particular build.

Greg, the first thought that comes to mind are the center sections one would see in Prettner's prototype models - notably the Magic. He used to fit 4 servos in there plus electromechanical mixers. Needless to say, the middle of the wing was barely existent!

I didn't see any pushrods emerging into the center section for the retracts but, obviously, if you need a retract servo in the wing, you're using mechanicals. I think this is the focal point of the installation. You'll want that servo installed where it needs to go. Also, I've found that the opening in the wing typically needs to extend beyond the width of the servo to accommodate the retract pushrods. Often this is done by cutting out a circle around the servo output shaft but only to a 1/2" depth at most. Some modelers (e.g., Dick Hanson) seem to be able to do without but I find it makes for difficult maintenance in that area.

The layout you planned strikes me as the second best option to go with. I think, in this case, the best option might be to install them parallel to each other span wise in the wing with their output shafts centered on the wing root centerline. Front servo would be retract and rear servo flaps (evidently). The rearward motor area of the servos would then extend outboard along the wing. Removing material span wise in the wing is not so much of an issue as it is glassed all around. Removing substantial material chord wise at the root has a more significant impact as this is the junction of the panels. However, in flight as well as in landing, the main stress on the wing is not at its center junction so there shouldn't be a need for too much concern.

Personally, my concern is always with the wheel well area as this is the section where the most material is removed and often where wings do fold if they do. I'm just now considering whether to glass the foam cores in the landing gear area back to the root prior to sheeting - something recommended in several pattern built instructions. Others recommend glassing the sheeted bottoms out to this area. Something else to consider is that in all likelihood the retract servo will be installed deeper in the core with the servo wheel inside the wing. For the flaps, this is probably not the case - you'd just have the output shaft emerging from the wing top. This allows you to remove less material for the flap servo and position it further back with two wells separated by an undisturbed center section portion. In glassing, you can also go into these wells chord wise to bind everything together. I would also use epoxy for gluing these wood wells at the root rather than some other lighter glue.

I'm not sure to what extent you glassed your wing center section but on first glance it appears to be a ~2" strip of heavier (2-5 oz) cloth across the junction followed by 3/4 oz out to 2-3" either side. If that's the case, I might be inclined to add another layer of 3/4 oz cloth out to the retract bays on the bottom and likewise on the top extending 1/2" beyond the fuse saddle after you've made and installed the center servo wells. On 60 size models I personally don't use 3/4 oz cloth (too light) on the wing center unless its part of glassing in preparation for a paint finish - perhaps you didn't either (can't really tell).

In short, I think you'll be fine with the center section but might want to pay a little more attention across the well area. The carbon fiber "spars" on the cores shown in the photo above are another nice and concealed way to add considerable strength to the wing with very little weight gain. Because of this and in the absence of flaps and since I'm using electric retracts, the wing center on my Tipo will be continuous and I may actually reduce the extent and weight of glassing. This first Tipo I'm building will be between 8 and 16 ounces heavier than the second purely on wood and fuse weight alone. GP considerably lightened their fuses as well as the wood used in subsequent kits. I think the latter kits, if built light and with lighter components could come in the 7-3/4 lb range (Greg, yours is one of the latter - I can tell by the fuse) while the earlier kits (like this first one I'm putting together) might end up closer to the 8-1/2 lb mark. I don't want to be an ounce over 136 - ideally 130.

David, try to be succinct will you! 'nough said.

David.