The Concord Battery Corporation is located in West Covina, California, with distributors for their products all over the U.S. They sponsor an ad in the Flying Wire on page 30. Take a look at their web site.
Their sealed lead/acid battery line has two sizes that are just right for the Stearman. Inverted operation is just fine and no drain tube down the gear leg is required.
They have a 25 amp/hr and a 35 amp/hr battery. I have been using the 25 amp/hr model and the performance has been outstanding. I run a 444-3 Bendix inertia/electric starter and at the same time power an electric driven oil pump for the engine pre-oiler. The starter comes up to speed and the oil pressure in the engine reaches 50 psi just before the engage solenoid is energized— all in about 20 seconds..
Now they have a 25-XC and a 35-XC model, (no increase in size) with the XC standing for extra cranking capability. I have seen the XC’s perform and they are even more impressive.
Faster turning of the engine during start goes a long way in reducing hard starting problems. The mags perform better!!
Another key observation is that Concord’s customer relations and support are just as good as the quality of their product. Often a rarity now days. Those two characteristics deserve our very positive recommendation for Concord batteries for the Stearman.