EAA Chapter 723
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Last Update:
January 10, 2001

Quiet!  Master Craftsman at Work

Building a Stewart S-51

Builder: Owen Smith

Well, if you haven't been in the hangar in the last oh, say, eight months, then you might have missed Owen's S51 that has been taking shape in the #2 hangar.  This man can build an airplane.  The quality is outstanding and the attention to detail is bordering on art.  We've all been watching as this beauty takes shape.  We've all cheered him on and watched in amazement as, little by little, you see the replica's shape emerge from the otherwise pile of parts.  Take a look below for an in depth look at the construction of this wonderful aircraft.

Project Summary

by Owen Smith

The Stewart 51 is an aluminum P51 replica at 70% scale. It comes as a kit with most of the metal forming, fitting and trimming already done. Most of the rivet lines are pilot drilled, then the airframe is assembled and pop-riveted together. The builder must generally take everything apart and reassemble it with structural rivets, install all the systems, etc. 

Pictures 1 and 2 show the start of this process. Here the fuselage and wings are stripped down to the skeleton and installed in simple holding fixtures. The S51 uses wet wings. The main tanks (70 gal) are in the inboard part of the wing aft of the main spar. I installed auxiliary tanks in the outboard part of the wing forward of the main spar. 

Picture 3 shows one of these tanks in pressure test. I leak tested each tank surface with water as they were put on and before the surrounding structure was closed. This made it relatively easy to find and repair leaks. The final tests with air were anticlimactic. Everything passed on the first try. 

Picture 4 shows the fuselage with most of the skins installed and the scoop and radiator attached. The scoop comes preformed, but the builder must do the trimming and fitting, install the radiator and the electrically actuated air outlet door. 

Picture 5 shows the vertical stabilizer and rudder. The rudder is fabric covered, just like the real P51. Trim/servo tabs are provided on the rudder, elevator and ailerons. Electric trim is used. 

Picture 6 shows the wings being mated. The wing halves bolt together at the root, just like the real P51. The missing sections of skin form the top of the main fuel tanks. It's easier to install the mating fittings before these are riveted on and sealed. 

Picture 7 shows the wings being mated to the fuselage. We lifted the fuselage with a couple of chain hoists, then rolled the wings underneath. The wings attach with four large bolts. 

Pictures 8 and 9 show the cowling installation. The cowling comes mostly formed, but the builder must fit and trim it. Generally, the installation is done working aft from the spinner backing plate to the firewall. About one third of the total fuselage length is forward of the firewall. The empty CG of the completed aircraft is about even with the forward edge of the windscreen. 

Picture 10 shows the first fitting of the engine and propeller gearbox. The engine is derived from a big block Chevy V8. The PSRU is a spur gear unit, like in the real P51. We use a prop from a Cessna Conquest. The intake manifold shown is popular with boat racers because the long runners give excellent low to mid range torque. We had to chop 2 inches out of it to get it to fit. Oh well, so much for the long runners!

Picture 14 shows the uplock assembly in the right wheel well. The gear retraction (tailwheel too) is electro-hydraulic. The landing gear, custom made wheels, retraction mechanism and Matco brakes are supplied with the kit.