Fuses armed by hand, when dealing with 5 tons of 120mm artillery shells, is a bad idea. Have them be armed by, say, a string that is ripped free when the bomb drops out of the airship's bomb bay or wherever it's stored.
I do like the idea of just reusing 120mm artillery shells, it's a good one. 5 tons of payload might be a bit much for our first-ever airship, though.
'Crate Mover' Truck
The internal combustion engine-driven automobile is a remarkable tool for moving things, like crates. So we've developed a small 1.5-ton truck with an unusually robust suspension system to aid our logistical efforts and begin to displace the horse as the primary tool of the logistics arm of our military. This truck uses an internal combustion engine running on regular old gasoline developed by our own engineering team and produced in our own factories, a first for our nation. In order to do this the engine is made simpler and perhaps proportionally a bit less space-efficient than most engines are, but since it aids in keeping it running and manufacturing it in a country not used to doing so we're pretty sure it'll be worth the trade-offs. Our (new) mechanics will undoubtedly be glad that we've tried to keep the truck easily maintainable and durable, at least.
It's got a flat bed that can optionally be covered, and can carry supplies or troops over its moderate range (for the time). For carrying troops we toss some bench seating in the back.
So some ICE experience might allow us to do an armored car to try and shift the balance of certain theaters, it would also improve our logistics immensely which might just have its own benefits.