Story ID: 
True Blue Power Energizes SIAI-Marchetti S.211
By: Matt Thurber
Caption: Weighs 45 pounds less than lead-acid battery and provides faster and cooler engine start
Word Count: 300
True Blue Power flew its SIAI-Marchetti S.211 military trainer/light-attack aircraft to EAA AirVenture Oshkosh 2026, following installation and performance validation of the TB50 True Blue lithium-ion main-ship battery.
Piloted by Mid-Continent Instruments and Avionics and True Blue Power president and chief test pilot Matthew Harrah, the S.211’s Pratt & Whitney Canada JT15D engine is exhibiting faster and cooler starts thanks to the battery. The S.211 is used for testing Mid-Continent and True Blue products.
The 50-amp-hour TB50 weighs 45 pounds less than comparable conventional 44-amp-hour lead-acid batteries and installs without modification. During engine start of the JT15D, fuel introduction happens in four seconds, compared to 12 with the lead-acid battery. The start cycle takes 24 seconds versus 39, and peak starting temperature is 342 degrees C, 90 degrees less than the lead-acid start. “It’s great for starting,” Harrah said, “whether it’s a round radial engine or a jet. A jet engine in particular, the speeds at which you can get it to start are critical to the health of the engine.”
The cooler starting temperature, he added, “helps protect the hot section, and it’s a lot easier on the starter-generator. It’s a lithium-iron-phosphate battery. There’s a lot of different chemistries, but lithium-iron-phosphate is one of the safest chemistries you can get. We put out a lot of power quickly and recharge quickly.”
There is “a very narrow CG on most of these old warbirds,” Harrah said, “so we were right up in the back end of the weight and balance envelope, and it moved it right into the middle. From a maneuvering standpoint, being in the center of the envelope is a huge advantage for us. We’re bringing a little extra margin of safety into our operation.”