• Wing Span: 54 in (137 cm)
• Wing Area: 980 sq in (6323 cm²)
• Length: 57.5 in (146 cm)
• Weight: 8.0 lbs (3.6kg)
• Engine: .60 2 - cycle

(9.8 cc 2 - cycle)
.90 - 1.20 4 - cycle
(14.7 cc - 19.7 cc 4 - cycle)
• 4 Servos required (5 recommended)

The Ultimate is a well thought out kit which uses CADD generated plans and a manual which includes step by step construction sequences, lots of photos and helpful hints along the way. Since this is the third Goldberg Scale Aerobatic kit that has been built, the lessons that were learned on the previous kits, a Chipmunk and an Extra 300, were applied to this kit.

As with the other kits, the Ultimate biplane features Interlocking Lite-Ply fuselage construction. This helps to assure a straight fuselage. Also, it has one of the worst landing gear configurations on the market. The lesson learned in building the Chipmunk were forgotten when building the Ultimate years later. The same incapable 1/8” lite-ply landing gear mount is used in all three models. The landing gear should be mounted on something more substantial such as a hardwood like maple, spruce, poplar, or a heavier plywood. The stock landing gear was replaced with a set of 1/4" x 3/4" aluminum landing gear struts. This results in a little bounce sometimes on landing but at least it eliminates the need to straighten the landing gear after every other flight. With this exception, the fuselage construction is truly a joy. Fuselages of other kits should be this easy to build. This fuselage was built within 2 days. The only part that was found to be tedious was the installation of the top deck sheeting around the aluminum cabane struts. Modifications were made to the interior of the fuselage to allow the use of a YS .60 rear exhaust engine with Hatori tuned pipe running through the fuselage. This makes for a very clean appearance, but it’s also a lot of extra work and is not recommended.

The engine cowling is made up of three ABS parts which is sufficient but the areas around seams, high stress areas, and screw holes should be reinforced with fiberglass. The same is true for the wheel pants. Fiberglass aftermarket parts are also available from other sources but they are expensive. As a matter of preference, the stock parts are made to work rather than buying the same parts twice.

The wings are a fairly straight forward design. The average modeler with some experience with other kits will not have a problem with this one. One change is recommended before starting the wing construction. The 1/8" lite ply ribs that have the mounting tabs to which the interplane struts mount should be replaced with ribs made of 1/8" aircraft plywood. The lite-ply ribs have not been a problem up to this point but it is always a point of concern when snap rolls and other violent maneuvers are done. Also, the single servo/bellcrank system that is detailed in the plans was used and resulted in very bad flutter during the first few flights. After the aileron gaps were checked, the ailerons were counterbalanced, and the wing incidences were checked, the decision was made to switch to separate, outboard mounted servos on the bottom wing. The servos must be mounted by laying them on their sides anda hatch made to cover them but this is worth the trouble when coming around the back side of a loop or doing a high speed diving pass.  

Some people have complained that the two 6-32 metal bottom wing bolts will loosen during flight. This has not been a problem with this model, but the problem may exist in others and should be a consideration during construction. Switching to 1/4-28 nylon bolts which thread into hardwood blocks is an option which may be considered. Another option is to use some type of silicone or Lock-Tite type product on the 6-32 bolts and blind nuts. The mounting of the top wing to the cabane struts is an excellent design. The wire rod through a plastic tube built into the wing center works very well and results in quick field assembly of the Ultimate. This type of mounting has been incorporated into a scratch designed and built G-38 powered biplane called the "Deuce".

The tail surfaces are built up from balsa sticks and then the horizontal stab and vertical fin are sheeted for strength. This results in a simple and light weight setup. The only recommendation to be made at this point is to replace the white nylon tailwheel bracket. The Ultimate has a very long tailwheel strut which puts sideways pressure on the nylon bracket causing it to flex and break. This was eventually replaced with a .60 size Du-bro tailwheel bracket which is heavy black plastic and is very sturdy.

The Goldberg Ultimate is a joy to fly. With the YS .60RE short stroke up front spinning an 11x11 APC prop it really moves. The plane tracks straight as an arrow and is very axial in rolls. The Ultimate does tend to rudder couple a bit on point roll and knife-edge maneuvers. Some pattern fliers have lowered the top wing on the cabane struts to bring it closer to the fuselage, but if a computer radio is used, it can be dialed out with mixing. The plane is capable of almost any maneuver within the abilities of the pilot. Takeoffs and landings are typical of any taildragger. This model comes in a little hot on landings but that could be caused by the high pitch prop used.

The Ultimate 10-300 is a very nice kit to build and fly and would be great sport/aerobatic addition to any hanger.