The Piasecki-Vertol Model 44B "Holy One" is being prepared for restoration at the San Diego Air & Space Museum's Gillespie Field Annex in El Cajon.

The Piasecki-Vertol Model 44B “Holy One” is one of the most unusual aircraft in the San Diego Air & Space Museum’s collection. Part of the H-21 helicopter family, this tandem-rotor aircraft represents a major step in the development of rotary-wing aviation during the 1950s. The H-21 was widely known as the “Flying Banana” because of its distinctive curved fuselage, a design that helped accommodate its two large rotors.

Developed for demanding transport, rescue, and utility missions, the H-21 family served with several military forces, including the U.S. Air Force, U.S. Army, French Navy, Royal Canadian Air Force, and West German Air Force. Its tandem-rotor design allowed it to carry personnel, equipment, and medical evacuation loads at a time when helicopters were becoming increasingly important to military and humanitarian operations.

The Museum’s aircraft carries a story that reaches far beyond its technical significance. While operating in Europe, it participated in the 1959 Italian earthquake relief effort. It later made a historic landing inside Vatican City, where it received a blessing from Pope John XXIII. That moment gave the aircraft its enduring nickname: the “Holy One.”

The interior of "Holy One."

Today, the Holy One is displayed at the Museum’s Gillespie Field Annex, where work is underway to prepare it for long-term public display. The aircraft is structurally intact but has reached a critical preservation point. Earlier work left the airframe in bare-metal condition, with the exterior finishes removed and the interior stripped. Without protective coatings, windows, and sealed exterior surfaces, exposed materials remain vulnerable to corrosion and environmental damage.

The restoration is being completed in phases so the Museum can stabilize the aircraft first, then continue with more extensive exterior and interior work as funding becomes available. Phase I is now nearing completion and has focused on protecting the aircraft from further deterioration. This work includes sealing the exterior, adding windows, installing the rotors, and preparing the aircraft for a protective coating. These steps are essential because they reestablish enclosure, reduce exposure, and help preserve the aircraft’s historic material.

The work has been made possible through the dedication of Museum staff and volunteers at the Gillespie Field Annex. Site Manager Carlos Romo and volunteers Richard Abraham, Gary Hafner, Larry Hoskinson, and Phil Lavullis have contributed their time, skill, and persistence to move the Holy One through this critical phase. Their efforts reflect the behind-the-scenes work required to protect large historic aircraft and prepare them for future public display.

Once Phase I is complete, additional work will continue in Phase II as funding is raised. Future restoration will focus on the aircraft’s exterior and interior, including historically appropriate finishes, additional detailing, and returning the interior as closely as possible to its original configuration using available parts. The Museum is working with Classic Rotors Museum in Ramona, which originally donated the aircraft, to help identify and obtain parts needed for this next stage. Interpretive elements will also be developed to help visitors understand the Holy One’s design, service history, earthquake relief role, and Vatican connection.

When complete, the Holy One will give visitors a rare opportunity to experience an early tandem-rotor helicopter whose story reaches far beyond its design. From humanitarian service in Italy to its remarkable Vatican City landing, the aircraft connects aviation history with moments of international relief, diplomacy, and public memory.

Support for the Holy One restoration will help preserve this rare aircraft and the story it carries, ensuring it can be protected, restored, and shared with future visitors.

The Museum's Gillespie Field Annex is located at 335 Kenney Street in El Cajon, CA 92020 and is open Wednesday through Sunday from 9 am to 4 pm. Visit here to learn more.