After discussing things over with your design staff, you decided that it would be worth it to make the modifications now, and get some millage out of the mecha workshop you had rented for the month. The modifications would be simple things you could integrate into a theoretical Unit 0-3 if you decided to make one, or were required to make one for further progress.
The first step to modifications would be to adjust the rake on the pilot's compartment. Originally there was a steep rake holding the vision port, and then a gentle rake back serving as the roof above the pilot, until it hit the spotter's position. Due to the weight of the top roof plate, a single-piece door wasn't really an option. Instead, after some thinking, your team designed a two-piece door that had a very nice set of overlapping flaps. Inside was a simple bar toggle to lock it closed, and a pair of simple handles. Since the roof didn't have any load-bearing components to it, you could easily put the door in.
The vision ports, however, were harder. Each vision port was a five centimer by thirty centimeter block of bulletproof glass, with a supporting shelf on the inside and outside of the tank. It took some thinking, but eventually you determined that if you reinforced the meeting plate between the forward plate of the driver's station and the side plate with an A-pillar, you could put the entire damn vision block on a door and just… open the door. Hinging would be a little weird, since you'd be using a knuckle hinge to get forward and upward motion, but it let you get good visibility over the feet so you'd take it.
The rest of the modifications came easily from there. Adjusting the seats, adding an optional backrest to the standing position for the pilot doing a road march, radium dials, and adding the internal comms wasn't too much trouble. The headsets were standard artillery-rated comms sets, and to change from internal comms to voice radio all the spotter had to do was slam a large switch in the cockpit.
Modifications done, you got ready for the endurance test. This was going to be a rough one, especially since you were participating as a driver. The plan was a hundred-kilometer total run around the perimiter of the artillery firing range, which would involve transversing roads, forests, plains, two sand traps, a river crossing, and a parking lot. It was expected to run two and a half hours, and would be the longest continual test of the mecha to date. It would also be a time trial, to see who was the fastest pilot.
For this test, you were in 0-2, St. Ignacio was in 0-1, and Montrove was in the 0-0, with race order being from lowest model number to highest.
Your race start was at 1425, and you went off the blocks without any major issues. Your years-long hiatus from mecha piloting wasn't slowing you down too much in your opinion, and the first half of the first leg was fairly easy open plain. The second half, which had a rolling hillside, was likewise fairly easy to traverse thanks to the stronger-than-necessary gyroscope and the autoballancing feet. Coming into the woods on the first turn, though, your speed dipped sharply as you started maneuvering around trees and through glades. The opened side doors did massively help visibility, especially in the instance you had to back up and move around a fallen tree covered with hull scrapes.
Once you were through the first turn you had to go through the first river crossing. This was accomplished quite gingerly, the meter-wide stream presenting a several meter wide danger zone of reduced ground stability and traction. Still, you avoided getting your feet wet, and plunked your way through the area before moving into some steeply cratered hills. The shell holes caused you a little trouble, but it was nothing compared to the sand trap that actually tripped you by causing a foot to twist hard enough to activate the safety disconnect. Limping out on five legs and a hobbling stride, you field-reset it (bring leg full up, flex knee joint out, roll hip back and forth, place leg down to set foot flat, dismount, attach seating cable, bring knee back up, wait for joint to go 'pop', remove seating cable and make a note for the shop to check it) and continued moving. The second sand trap was almost as treacherous as the first, but you cleared it without issues at glacial speeds.
The second corner was a water meadow, and once again your speed went from 'good' to 'glacial' as you tromped through the water. Worse, your engine temperature was steadily spiking upwards for reasons you couldn't figure out. Babying the engine until you were out of the water meadow, you frantically went through the gauges until you found the problem: the radiator temperature was sky-high. Since you didn't have a way to top it off, you'd just have to live with it.
The third leg of the course was difficult, not for the terrain, but in managing your engine heat. What few copses of forrest turned out to be easily enough handled, but any effort to bring speed up brought a new host of issues, up until the fourth leg, in which you had to share a road and make the minimum speed of 20kph. After twenty minutes at this speed, you smelled a hint of smoke, saw the radiator temp fall through the floor, and heard the distinctive 'tink' of the in-engine compartment extinguisher going off.
Taking a minute to shut down the fuel supply, you jumped out to inspect the issue and call in to the HQ for a pickup.
It turned out none of your units completed the course, sadly. 0-0 and Montrove had thrown out a hip joint safely when they'd had a leg tangle in the first forest, and 0-1 and St. Ignacio had the same issue you had: engine overheating, leading to a fire (although his was on the second leg, not the fourth.)
At this point, you had to load all three functional mecha back on the rail-cars, and get back to the factory. You had three weeks to go before the testing contest, and these god-damn engines were bound and determined to try and kill you along the way. Fine- if it wanted to make your life miserable, you'd return the favor, somehow. You obviously needed to expand the radiator and oil cooler, but that could wait. For now, you had a train ride to sleep through.
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VOTES
[] Build a through-body tunnel for airflow from the dorsal to ventral sides.
+ Fast and easy, with little re-engineering structurally
- Liable to have bottom-side debris ingestion, topside grills are a known vulnerability for anti-mecha munitions
[] Build a through-body tunnel for airflow from port to starboard sides
+ Can be used to cool entire engine compartment, including electrical generator and transmission.
- Creates side armor vulnerability, requires some structural redesign
[] Build a two-stage radiator with an external heat loop for the main heat sink
+ Fewest armor issues, and most difficult to disable
- Most complicated engineering, and adds weight for heat sink mass.
