The Eureka 4. This one had covered front wheels, a permanent back wheel, was the first to use a handle fork, and the last(?) to have a straight wood handle pole. Ad courtesy of Paul.
The Eureka 5. I have not found any ads or photographs of the 5 as of now, so will reuse the photo below of what I think the 5 could look like. No tool port, but keeps the stationary back wheel and uncovers the front wheel. Also adds a comically curved metal handle.
The Eureka 6. Much like the possible 5, the only change this one appears to have is the addition of a rear caster wheel instead of a fixed one. Pics courtesy of Royalsuper.
The Eureka 7. Early 7s had the old style bag and a brass name plate, but later ones like mine had an aluminum tag and a bag with an updated logo and spreader at the top. Ad courtesy of Paul.
The Eureka 8. Still speculative on this but some patent drawings back my theory. The first with a cast handle fork(no catch), the first with wheels behind the head, but the last to use the old style friction fit bag. Bag in pic is a replacement.
The Eureka 9. Mine is a 32 volt DC version, but AC 120 volt versions have a standard black aluminum tag. 9s before the 1 million mark had a longer handle and a rear housing with slightly bigger vent holes. The first to have a pot metal switch tab, and all 9s had a handle fork catch on the back of the fork as well as the introduction of the click on bag collar. Also the first to improve the bag, moving the clip to the top to reduce wear.
The Eureka B(Special). Mine has a genuine replacement bag. This used a much larger motor, but kept every other piece of the 9. Sold alongside the Standard as the budget option. Ad courtesy of Portable.
The Eureka F(Standard #2). This is quite an odd one. Switch on the back of the handle, height adjuster on the nozzle with a model G type axle, and grooves cut into the head. Sadly mine has no bag as of now. I cannot find any ads at all for this.
The Eureka A(model 10/Standard #1). The 10 and 11 used the same prefix, A, along with the term Standard. The only change between them is the 11 added a 2 piece, quick removal handle fork. These models had the height adjuster on the fixed rear wheel.
The Eureka A(model 11/Standard #1). The 10 and 11 used the same prefix, A, along with the term Standard. The only change between them is the 11 added a 2 piece, quick removal handle fork. These models had the height adjuster on the fixed rear wheel.
Ad courtesy of Paul.
The Eureka D(Deluxe). This one had an updated head with a brush built in, a full wood handle grip, a switch behind the handle, and 4 wheels instead of 3. Mine was in rough shape, so I custom painted the once rusty accents red and got it a matching bag. This one also had its height adjuster in the front.
The last of the straight suctions, and the only one to use ball bearings and have no external wire terminals. Prewar versions were polished with a wood knob on the handle, and of course the rear handle switch. Postwar, commercially sold ones like mine had a metal handle cap, a grey hammertone finish, and a modernized bag. The K also had a simplified mechanism for retracting the brush strip. Ad courtesy of Paul.
Into the motor brush models. The Eureka G. Early iterations had a wood grip and a speed switch underneath, mine is a mid range with just a wood cap on the handle and no speed switch.
The Eureka G2. Early G2s looked more like the G but with a side sitting bag. Late G2s had a headlight option(as does mine), an updated bag logo and shape, and updated badge. All G2s had a larger, more powerful motor and later ones had a rubber strain relief instead of a spring. Ad courtesy of Portable.
The Eureka R. Early Rs had pinstripes embossed and painted on the castings, along with an old style logo on the bag and badge. Later versions(like mine) updated both of those and ditched the pinstriped accents on the aluminum as well. The first truly 2 speed Eureka, with both speeds in the handle. Ad courtesy of Portable.