X-15 pilot report, part 3:
X-15 Flight:  Heading Out to Launch

X-15 carried on wing of B-52 before launch

You, the pilot, arrive at the Base while others are finishing final fueling and system checks in the hours approaching dawn. X-15 preflight preparation at dawn
You'll start with the X-15 already hanging from a pylon on the B-52 carrier aircraft. Don't bother with a nitty gritty total hardware preflight; the taxpayers thoughtfully provided a whole staff to do it for you. Anyway, you're cooped up in a pressure suit, prebreathing 100% oxygen.

X-15 final preflight preparation
After entering the cockpit, strap in and and run through the interior check. That's 120 checklist items, ending with "close canopy". By now the B-52 is supplying power, breathing oxygen, nitrogen, and liquid oxygen to top off loss from the oxidizer tank.

That LOX loss is due in part to precooling the engine, which you initiate in the captive takeoff checklist. While precooling, LOX flows through almost all of its usual path to the engine, then dumps overboard at the liquid oxygen prime valve. You'll precool for 10 minutes, then start a schedule of 20 minutes off and 7 1/2 minutes on.

B-52 takeoff, carrying X-15 Takeoff isn't just you and the B-52.  Typical missions will add three chase planes, rescue helicopters, a C-130, and an array of ground vehicles deploying to places between your planned takeoff location and Edwards.  Some of this force goes to dry lakes that might be needed for emergency landings along the planned route of your flight.

A few things will need heat during the climb, so be sure to turn on the heaters for the windshield, your face mask, and the nose ballistic rockets (the X-15's nose, not yours). Also ask the B-52 crew about the hook heater.

X-15 just prior to launch from B-52 Once at altitude, go through the 27-item prelaunch checklist. Among other things, you'll switch to the X-15's breathing oxygen, shut off liquid nitrogen but not gaseous nitrogen from the B-52, and start the APU's.

Next comes the 29-item precountdown checklist. Among other things, you will:

What happens when you go to igniter idle is this rapid-fire sequence:   When the 2nd stage igniter and main chamber build to 150 psi, about 5 seconds later, the jet into the main chamber is sufficient to light it up. You're ready to go, so ask for the countdown -- fast!

They're serious about that 30 second time limit for either lighting up or shutting down. When there's 7 seconds more of idle time allowed, an IDLE END caution light comes on. When time runs out, a NO DROP light tells you to shut it down.

So... when you get through the brief countdown and you drop, don't waste much time before moving the throttle from OFF to at least 50%. That'll light the main chamber, giving you the second part of a big one-two punch.

X-15 drop from B-52 Part 1 was the drop itself. Starting to fall may sound like a gentle and mellow start, but it can feel more like being catapulted straight down. In the early flights even a short countdown wasn't adequate preparation when the B-52 crew initiated the drop -- NASA soon rerigged the system so that it would be the X-15 pilot who tripped the release, giving you at least a feeling of being just a bit more ready for the event.

This pilot report is split into these four parts:

    1.  X-15 General Description & Walkaround
    2.  X-15 Cockpit Check
    3.  X-15 Flight:  Heading Out to Launch
    4.  X-15 Flight:  Flying the Mission and Returning

Related to all four sections:

    Photo credits and pointers to related resources

Send questions and comments on the SierraFoot X-15 pages to Paul Raveling.
Return to   X-15 pilot report root page    X-15 home page      SierraFoot site home page