A Tear in the Silk — Louise O'Flaherty

In horror, Nora McShane watched her father die in the balloon hed designed, hurtling downward. Nevertheless, she agrees to build a dirigible from his plans, in partnership with another aeronaut, Wolf Sanger, and puts aside as irrational her fears at living and working in his secluded mansion. But someone wants the dirigible to fail. Wants it badly enough to murder.