>> As of August 2016, a scaled version of the[12][verification needed] Raptor engine has been shipped to Texas where it will undergo development testing.
I was looking at the pics and thinking this thing is way too small for what it is meant to be. But after reading wikipedia I understand. The pics/tests are of a tabletop version. The real engine hasn't been built yet. So it's good news, but not the news I was looking for.
Title should perhaps reflect the fact that the "new powerful engine" doesn't yet exist for testing.
You can see a staircase to the bottom-right, and the railing on the left side (if built to code) is likely 38" tall. It looks like the nozzle is roughly a meter across.
Everyone is rightly pointing out that it's not a huge engine, but two things to keep in mind.. Musk's ISP figures correspond to operating in a vacuum and of course at that point the bell will be significantly larger (14ft like mentioned). If used for the first stage, the Raptors will likely have similar-sized bells to the current Merlin engines. The bell is just the expansion chamber and doesn't really relate to the actual engine size (except of course to optimize expansion ratio).
The shuttle engines weren't huge, but the bells were quite large, I think the expectation is that the Raptor will be between 1/2 and 1/4 of the Shuttle engine size/weight:
Those are still tiny. Unless Musk has invented some new radically new classical physics, that bell is nowhere near big enough to match the shuttle engines, not at the published isps. Maybe I'm wrong and he deserves a noble prize. Or maybe his tweets aren't the full story and this is a scaled technology demonstrator.
Perhaps someone should rewrite the raptor's wikipedia page to indicate that raptor is in a different league. Pics from this "test firing" are right beside numbers claiming thrusts above shuttle, which is comical given the size differences between the engines.
This is thought to be the Raptor prototype SpaceX is developing under a USAF contract for a methalox Falcon 9 upper stage concept.[0] Thus it's about the size of a Merlin 1D-Vac. Nobody is claiming otherwise.
From /r/SpaceX, the estimates is that this is a Raptor engine at similar size as the Merlin engine they currently use in Falcon 9.
If so, it'd be about 1/3 size of the "real" Raptor. Though, they also have a contract to develop a Raptor-powered F9 upper stage, so this size could be potentially for that.
His latest tweets are a bit hard to interpret but they say target thrust is 3x Merlin, and 3x chamber pressure, meaning they look similar size if they have a similar area ratio.
I think the combustion chamber and throat are going to be of roughly similar size, but Raptor is going to have a bigger nozzle, because if you expand to ambient (or slightly below), the higher pressure engine naturally has a larger area ratio.
Anyway, in general, the nozzle in a high pressure engine can be a little smaller for the same thrust, but that effect is not 3x.
Maybe they haven't yet fabricated the big nozzles so they first test it in a very underexpanded condition.
> His latest tweets are a bit hard to interpret but they say target thrust is 3x Merlin, and 3x chamber pressure, meaning they look similar size if they have a similar area ratio.
Does it mean three Merlin engines can be replaced with one Raptor engine?
>> As of August 2016, a scaled version of the[12][verification needed] Raptor engine has been shipped to Texas where it will undergo development testing.
I was looking at the pics and thinking this thing is way too small for what it is meant to be. But after reading wikipedia I understand. The pics/tests are of a tabletop version. The real engine hasn't been built yet. So it's good news, but not the news I was looking for.
Title should perhaps reflect the fact that the "new powerful engine" doesn't yet exist for testing.