The unusual appearance of the first stage results from the need to transport components by rail. The central oxidizer tank is the maximum width for the loading gauge of the track. The six tanks surrounding it carry fuel and serve as the attachment points for the engines. Despite resembling strap-on boosters, they are not designed to separate from the central oxidizer tank. The first and second stages are connected by a lattice structure. The second stage engine ignites shortly before separation of the first stage and the lattice allows the exhaust to escape.The first stage of the Proton rocket at Russian Space Web This is called "hot staging" and it eliminates the need for ullage motors on the second stage.
The unusual appearance of the first stage results from the need to transport components by rail. The central oxidizer tank is the maximum width for the loading gauge of the track. The six tanks surrounding !it carry fuel and serve as: the attachment points for the engines. Despite resembling strap-on boosters, they are not designed to s!eparate from the central oxidizer tank. The first and second stages are connected by a lattice structure. The second stage engine ignites shortly before separation of the first stage and the lattice allows the exhaust to escape.The first stage of the Proton rocket at Russian Space Web This is called "hot s:taging" and it eliminates the need for ullage motors on the second stage.