SR-71 Blackbird

Here’s why the SR-71 inlets had to be labeled “L” and “R” and why the Blackbird had engine and afterburner fuel control cable pulleys

The SR-71 engineering was so cutting edge that even the tools to build the Blackbird needed to be designed from scratch.

CLICK HERE to buy unique SR-71 Blackbird T-Shirts!

During its career, the SR-71 Blackbird gathered intelligence in some of the world’s most hostile environments.

The SR-71 was conceived to operate at extreme velocities, altitudes and temperatures: actually, it was the first aircraft constructed with titanium, as the friction caused by air molecules passing over its surface at Mach 2.6 would melt a conventional aluminum frame.

There are so many interesting facts about the legendary Blackbird.

When I used to walk around the SR-71 with my father, Butch Sheffield (former Blackbird RSO), he would point to the “L” on the one inlet of the SR-71 and smile and say, “Minter.” Colonel Minter ordered that every SR-71 in the inventory be labeled to make sure that It was clear which was the left from the right.

SR-71left inlet labeled “L”

Early in the Blackbird program, a mishap happened on SR-71 #964: damage was done to the engines when they were placed in the wrong inlet.

Former crew chief Floyd Jones elaborates more on the story;

‘They will fit, but they are canted outboard instead of inboard. It happened on 964; she flew with no problem until checking the inlet’s major damage on spikes and center body also FOD the engine.

‘Reason it happened was they did something out of the usual. Both spikes were left on one side of the hangar. Usually, when a spike was removed was left on that side of hangar.’

SR-71 right inlet labeled “R”

John Olp, SR-71 engine expert, told me something I’d never heard before about the cutting-edge engineering of the Blackbird.

‘The right engine throttle linkage was connected to the afterburner fuel control, and the left engine throttle linkage is connected to the main fuel control!

‘The aircraft throttle linkage was connected to the afterburner fuel control on the left engine and the main fuel control on the right engine (inboard side of the engines).

‘It absolutely did matter because of the two different functions.’

Olp adds more details;

SR-71 Blackbird engine and afterburner fuel control cable pulleys.

‘The two fuel controls were interconnected by a pulley and cable system in order to be fully synchronized. There was a pulley on each fuel control with a steel braided cable running underneath the engine, around more pulleys, so that, whatever position you set one fuel control at, the other one moved with it!

‘Afterburner fuel control on the right, main fuel control on the left. The aircraft throttles were connected to the threaded portion sticking out of the pulley shaft.’

So today when you visit an SR-71, walk up to the inlets and look for the “L” or the “R” and you will know a little story about why they are marked left and right.

This print is available in multiple sizes from AircraftProfilePrints.com – CLICK HERE TO GET YOURS. SR-71A Blackbird 61-7972 “Skunkworks”

And remember! On the Blackbird the afterburner fuel control is on the right, the main fuel control is on the left.

Be sure to check out Linda Sheffield Miller (Col Richard (Butch) Sheffield’s daughter, Col. Sheffield was an SR-71 Reconnaissance Systems Officer) Facebook Pages Habubrats SR-71 and Born into the Wilde Blue Yonder for awesome Blackbird’s photos and stories.

Photo credit: William Franklin Cely, Linda Sheffield Miller, John Olp and U.S. Air Force

This model is available in multiple sizes from AirModels – CLICK HERE TO GET YOURS.
Linda Sheffield Miller

Grew up at Beale Air Force Base, California. I am a Habubrat. Graduated from North Dakota State University. Former Public School Substitute Teacher, (all subjects all grades). Member of the DAR (Daughters of the Revolutionary War). I am interested in History, especially the history of SR-71. Married, Mother of three wonderful daughters and four extremely handsome grandsons. I live near Washington, DC.

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  • The SR-71 was created several decades before the DoD even tried to consider the maintenance personnel's view of maintainability. Ridiculously complicated, confusing, and confounding equipment was purchased. Lockheed may have been great at achieving performance goals, but they were notorious for making products that were ridiculously confounding to work on.

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