Red Bull Powertrains will be working in conjunction with Ford to help deliver the engine that will power the current world champion squad for F1’s new rules era.
It already has its dynos hard at work in evaluating the performance of its new turbo-hybrid design.
And while there have been various rumours about the level of progress Red Bull is making with its project, Horner insists everything is on track.
Speaking to Motorsport.com about where things were at, Horner said: “With the engine, we're on an aggressive curve being a brand new power unit manufacturer. But the team is really rising to that challenge.
“Our facilities are complete, both from a test and development point of view with dynos and rig rooms, etc, and manufacturing capability.
“But two years in the engine world is a very small period of time. We're on a steep learning curve, but we're on that curve and where we would expect to be on that curve at this point in time.”
While Red Bull does not know the progress that is being made at other manufacturers, Horner says that it laid out some performance levels that it reckons it needed to reach on its roadmap to 2026 – and that are being met so far.
“We are hitting the targets that we're setting ourselves,” he said. “Now, how those targets stack up to our competitors is always difficult to know. But the effort that's going in behind the scenes is huge, because it is literally a race against the clock to the start of 2026.”
The uncertainty about the performance of Red Bull’s 2026 power unit prompted speculation earlier this year that it could be a factor in prompting Max Verstappen to question his long-term future at the squad.
However, the three-time world champion insisted that it was far too early to be concerned about how things were looking this far out from the engine running for the first time on track.
“I mean, if I have to speculate about everything... I might be worried if I'm still alive tomorrow, right?," the Dutchman said about any potential engine fears. "So, I don't really worry about that too much.
"Of course, I am in close contact with Christian about that and the people working there. Everyone's working flat out, so there is no need to panic about that. It's still not 2026.
"We know that it is a very big task, we don't take that lightly. And of course, with so many well-established engine manufacturers, we also don't think it's going to be easy to beat them.
"But we have a lot of good people working on the project and we're very excited about it. So time will tell, of course, where it's going to be."
