Important to always check when buying or restoring. Check for hairline cracks in the butt side of the main spar. The upper and lower main pin holes of the spar should be connected together with steel straps. An aileron flutter modification should be present. To be checked in the luggage compartment. Four bolts & nuts should be seen in the middle on the front wall. If yes, the mod is been done and the torsion rods from aileron and brakes should be supported. If this is not the case flutter can occur at higher speed with permanent damage or even loss of the ailerons in flight. Mass balance weights at the underside of the ailerons. Schempp Hirth airbrakes are only mandatory in The Netherlands. The Sagitta is no longer fully aerobatic and usually downgraded to utility class flying. Aileron hinge screws can be rotten. This can only be checked by cutting a hole in the surface skin.

Mandatory modifications These modifications should should have been done for safety reasons. Take contact with Charles Munnig Schmidt if in doubt, or if you need more information. 1964 List of modifications from the factory. Check if your Sagitta has been updated with these in it's history. Dutch and New Zealand Sagittas have been fitted, but not all countries have received this list. Balance weights (lead) on the ailerons. Although it's not necessary to apply the original prescribed weight, see section "non mandatory mods" below. This is to avoid flutter at higher speeds, or pilot induced oscillation of the wings. There is a little story connected to this. Louis van Rijn got the following story from Frits Holler in 1975: "If you were flying faster than 110-120 km/h, let go of the stick and then gave it a wack to one side, the ailerons would start fluttering. The stick would swing back and forth and increasing the speed by trimming forward or lightly pushing it forward would make the wings oscillate violently. Holler didn't dare to experiment over 160 km/h, but warned the Dutch RLD (Civil Aviation Organisation) and the Sagitta got a Vne limitation. After that the aileron balance counterweights became a mandatory AD. Although most Sagitta's have been modified, there are still one or two flying without it. Care should be taken in flying at high speeds - take contact with Charles to apply the modification. Pictures to be followed soon. More reading:  A story of aileron flutter to be found here. Main spar modification . This implements mounting metal straps (see pictuure) or a metal cuff around the spar ends, resulting in sometimes having to modify the fuselage as well (see picture). After discovery of hairline cracks in the main spar ends of s/n 010 in New Zealand, the factory issued a modification of the spar. Details here.

Non mandatory modifications Why did so many Sagitta crash in the early days? With Charles' own words: "it is true she can react quite bitchy and the wing can hook in a turn". This can be fixed by adjusting both ailerons 10 mm upwards (at the rear side of the wing at the aileron root). In effect this means a smaller angle of attack. This works very well and definitly raises the flight characteristics. When the Sagitta was designed one thought that just a change of profile (from NACA 63 3 618 to NACA 4412) would be sufficient to let the wing tips stall later than the rest of the wing, in stead of teh classical "wash out". A similar design is to be found at the Slingsby Capstan - and that didn't work well either... Counter ballast of the ailerons . Taking away half of the amount of lead under the ailerons seems to make the ship fly much lighter. Has been tested up to 240 km/h (130 Kts) without any problems. Enlarging of rudder surface . The 3 flying Dutch Sagitta's have all been modified with a larger rudder. This was achieved by adding a few extra centimetres at the trailing edge of the rudder. Normally the Sagitta is a bit under-ruddered in turns, and this will fix the problem. Picture on the left shows a rudders now sticking out a bit further over the end of the tail cone. Left hand picture is with original sized rudder. Installing aileron fences . Succesfuly done on a few Sagitta's in later years. This will enhance the low speed effectivness of the ailerons. Especially handy at paddock landings without the Schempp-Hirth brakes.... Modifying the original air brakes . These can be made substantial more effective by drilling holes in them, to disturb the airflow. Especially effective on the upper brakes, a bit less on the lower ones. See pictures.

Repairs & Maintenance Play on both tailplane halves seems to be common. This can be fixed with an adjustable roamer 12 mm (from 10 to 14 mm), welded on a long rod. This way you can roam the hole inside the tailfin. The new bolt to go through the holes should be Chrom/Nickel steel 5.123 welded on the assembly rod. Apparently it is not possible to remove all play, but this should help a lot. If both elevator surfaces have play relative to each other this can be fixed easily. It is a common problem with the Sagitta. You will need small pieces of hard wearing plastic about 3mm thick. Cut these so they will fit inside the elevator drives at each side. Mount these plates then on the forks sticking out of the fuselage at each side with two M4 bolts and self locking nuts (2 pr. side). Be sure to make the bolts short enough to avoid scratching the fuse. Of course assembly will thereafter be even more difficult than before, but the play will be gone....   Aileron hinge screws can be rotten at the inside of the ailerons. Here is what Howard Petri found: "I opened my ailerons to replace the aileron hinge screws. They were almost eaten away, the only real damage I found. You might want to check these screws. Unless you remove them you would never notice the problem. This means cutting holes in the aileron though. Well worth it in my case." Rudder cables. Change to stainless steel (no rust) if allowed. (Howard Petri). Main pins and rear spar pins. If the main pins and/or the pins connecting to the fuselage get excessive play, this can be fixed by roaming out the holes and manufacturing new pins. Roaming can be done by following Schleicher Ka-6 standards. This has been done with s/n 010; upper main pin from 30 mm to 30.5 mm and aft pins from 12 to 12.5 mm.