Aircraft engine manufacturer Pratt & Whitney is forecasting nearly 60 percent growth in its business by 2020 driven by huge demand for its new commercial engine series, but its program to provide the power plant for the F-35 Joint Strike Fighter program will ensure that the company’s wedge of military business expands consistent with the rest of the portfolio, according to company officials.

Pratt & Whitney, one of United Technologies Corp.’s [UTX] four operating segments, had $14.5 billion in sales last year and projects its business to reach around $24 billion at the end of the decade. The company’s military business makes up 25 percent of the work, with large commercial engine volume at 50 percent and its Pratt & Whitney Canada unit the remaining 25 percent.523a2574b6f80-rsz_b-2-4_f135-stovl-cutaway-high

That balance among military engines, large commercial engines, and the Canadian unit  “holds form all the way through that growth” trajectory to 2020, Bennett Croswell, president of Military Engines for Pratt & Whitney, told Defense Daily during an April 3 interview at the company’s facilities in Hartford, Conn., as part its annual media day. “We’ll remain about a 25 percent share of the total Pratt & Whitney business as we grow the business” through 2020 and beyond.

The driver behind the company’s coming surge in commercial engine growth is its new Geared Turbofan engines, the PurePower PW1000G engine family, which will enter service later this year on the Airbus A320neo single aisle passenger plane and will also be flown on a number or regional and business jets.

Pratt & Whitney is currently building about 800 large engines annually and expects that to rise to more than 1,800 per year in 2020, with two-thirds of the expansion coming from the Geared Turbofan engines, Paul Adams, president of the engine making company, said at the media day. Production of the F135 engine that powers the single-engine F-35 will more than double during this period, he said.

While the number of Geared Turbofan engines will outpace the F135 production volume, there are about four times the shop hours that go into producing the F135, which is due to the fact that it’s a more complex engine and is built entirely by Pratt & Whitney whereas the new large commercial engines get components from partner companies, Croswell said. The higher amount of shop hours leads to a higher price, which is how the military revenue will stay balanced throughout the company’s overall growth in the coming years, he said.

Currently about 100 F35s are fielded today and more than 600 by 2020. The Marine Corps’ short take-off and vertical landing variant of the F-35 is scheduled to achieve initial operating capability this July and the Air Force conventional take-off and landing variant next summer. So far, Pratt & Whitney has delivered 215 F135 engines and plans to deliver more than 600 by 2020.

The United States and its international partners plan to purchase more than 5,500 F35s through 2039.

The F135 is the largest component of Pratt & Whitney’s military engine business. Croswell said there is also a major focus on sustaining the engine for both the U.S. military services and the foreign partners that are purchasing the F-35.

Croswell said there is potential in the years ahead to expand the military engine business as a portion of Pratt & Whitney’s overall business base. This could happen if the company, through a joint venture with Honeywell [HON], is ultimately selected to produce new turbine engines that will be installed on new production and retrofits for UH-60 Black Hawk and AH-64 Apache helicopters. The Improved Turbine Engine Program is also a candidate for a Future Vertical Lift helicopter.

Pratt & Whitney and Honeywell are in the science and technology phase of developing the HPW3000 engine for the ITEP program. The Army is expected to release a Request for Proposals in mid-2015 for an 18-month preliminary design phase that would end in 2018 and then downselect to a single contractor with production beginning early next decade.

Pratt & Whitney engines currently don’t power any of the Army’s helicopter fleet.