Why is Sentinel not in Proto-form on the Ark but already a fire truck?

 

To save money and effort.

 

Simple

 

He's neither, he's in his Cybertronian form. A Protoform is just the bare skeleton, not their Cybertronian forms or Earth forms. If you look Sentinel has no distinguishable firetruck kibble such as tires or lettering on him.

 

Because you have a bad eye for detail.

 

Until you buy the disc.

 

This. There are subtle differences in both colour and form between his Cybertronian mode (on the Ark, during his revival) and his Earth mode (rest of the film). Not much, but just enough. Think of how Animated did it. The Cybertronian modes and Earth modes are clearly different, but still identifiably character X or Y.

 

Furthermore, while not explicitly stated, Sentinel pretty obviously gets his alt. mode from NEST HQ, which not only has an airstrip (necessitating the presence of airport firetrucks), but also the numbers of the installation's floor levels seen in the background of many shots correspond perfectly with the 316 emblazoned upon the side of Sentinel's alt. mode.

Level 316 presumably being their motorpool level or some such, I suppose.

 

Actually you can see a similar crash tender in the background during some of the NEST base scenes. When the Autobots first arrive (when Sentinel is still on the moon) and behind Optimus pulling in following Sentinel's rampage. In fact it might be the exact same truck since it's always in very background in poor lighting, presumably to obscure the fact that it's the Sentinel truck, since Sentinel has prominant Autobot symbols on him.

The also have a 2nd crash tender, though it's of a different make than Sentinel's Panther one.

 

When Optimus picks him up, you can see where his wheels usually go that there are no wheels, just rims-looking things. And his legs don't have the "316" number that they do after he gets the alt mode.

 

It's not the Sentinel Prime firetruck or a firetruck at all. It's one of the giant-@$$ military vehicles that are all around the NEST base (check in the background of the "...it was carrying an Autobot technology which would've won us the war..."-shot).

 

Yeah, I had the same thought upon first noticing the truck following Optimus in when he arrives to survey Sentinel's damage to NEST HQ (since you really only see the cab portion enter the shot, which has roughly the same profile as Sentinel's alt. mode), but once I'd spotted it and noticed the rest of the vehicle earlier in the film upon later viewings, it was clear that it was not another Rosenbauer Panther.

Ho hum.

 

THIS.

Yeah, it's easy enough to get them confused, since you only see like, 35 frames of the military vehicle, which - as Hazekiah pointed out - have a similar profile for the front portion of the cab. But a high-res screen cap would easily prove the differences.

 

What this dude said.

 

Besides he didn't have to go into his protoform body and transform into an entry mode, no he was on the Ark.

 

!!THIS!! ^^
I believe we've had many threads and posts bout this

 

Just for the record...

I grabbed my DVD and plopped my Army dad in front of the TV for a minute to try and identify that "Hawkeye" UAV in TF otM since it's been baffling my every attempt to identify it so far and since he's been deeply involved with Future Combat Systems since the beginning.

No luck there yet (Anyone? Anyone?!?), but just for the hell of it I skipped to a couple of the shots of the vehicle we're talking about here and it's some variation of this:

Oshkosh 8X8 H.E.M.T.T.
(Heavy Expanded Mobility Tactical Truck)
​

Apparently there are about a billion different configurations for which it can be outfitted, so it was tricky to nail down more than that from the few quick peeks I could show him on his crappy office TV.

But it's a good head start!

Anyone?

 

its not to save money cuz in the previews they had him gold and shit so they obviously already had the sceen

 

There we go! Good work, Hezekiah.   That (or a variation of it) is what follows Optimus into the NEST base after Sentinel attacks, not the Sentinel firetruck.

 

Cybertronian form =/= Protoform