# What are all those dials on the SR-71 Blackbird for? **URL:** \ **Category:** Factual Questions\ **Created:** [July 31, 2010, 12:39am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641 "2010-07-31T00:39:37Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [July 31, 2010, 6:01am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/21 "2010-07-31T06:01:06Z")
> [@Shagnasty](#): > > That cockpit is more simple than I thought it would be. Instruments on multi-engine planes are single or dual purpose for the most part. Old school airliners were way more complicated than the picture shown in the OP. The basic instruments for any airplane are an altimeter, attitude indicator, airspeed indicator, compass, heading indicator, turn indicator, vertical speed indicator, radios, and navigation equipment. On multi-engine planes, you also have engine monitoring instruments, fuel instruments, temperature sensors. Many of these instruments need to be redundant because they are prone to failure. There are actually very few instruments that are duplicated for redundancy.[A Dash 8](http://www.airliners.net/photo/Cobham-Special-Missions/De-Havilland-Canada/1532432/L/&sid=b411889b1576e9b89931b55f18e8fe67) has a standby (third) altimeter, a standby (third) attitude indicator and just one magnetic compass (backup for the HSI and RMIs.) Everything else is one per pilot or one per engine. Instead of additional gauges redundancy is achieved by having duplicate power sources for the important instruments (pneumatic instruments such as altimeters, vertical speed indicators, and airspeed indicators have a backup air supply.) Something to note with cockpit pictures is that all of the engine instruments and controls will normally be represented once for each engine\*, so a B747 will have four of everything. This makes cockpits look more complicated than they really are. \*[The Shrike](http://www.airliners.net/photo/Rockwell-500S-Shrike/1668763/&sid=d1f65d2adf7f62cea16d8f8bb2f505f5) is one aircraft I’ve flown that had dual needle engine instruments. The manifold pressure, for example, was shown on one instrument with two needles. It made it easy to match engine indications and you can see from the photo that space was at a premium. ---
**Author:** ![Johnny\_L.A](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/johnny_l.a/32/1084_2.png) [@Johnny\_L.A](https://boards.straightdope.com/u/Johnny_L.A)\ **Post date:** [July 31, 2010, 6:41am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/22 "2010-07-31T06:41:13Z")
This thread reminds me of a cartoon I saw once. An airline pilot is talking to a visitor in the cockpit. ‘All these dials? They’re mostly just for show. But don’t tell anyone, otherwise _everyone_ would want to be a pilot!’ ---
**Author:** ![ralph124c](https://avatars.discourse-cdn.com/v4/letter/r/8797f3/32.png) [@ralph124c](https://boards.straightdope.com/u/ralph124c)\ **Post date:** [July 31, 2010, 6:57am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/23 "2010-07-31T06:57:07Z")
Sorta related-a few years back, the Honda Prelude had a unique design speedometer/tachometer that used the same guage face-the tach needle was inside the speedo needle-I liked the look. Most people didn’t-they drpped the design. ---
**Author:** ![panamajack](https://avatars.discourse-cdn.com/v4/letter/p/47e85d/32.png) [@panamajack](https://boards.straightdope.com/u/panamajack)\ **Post date:** [July 31, 2010, 7:07am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/24 "2010-07-31T07:07:09Z")
#18 - Shaker Indicator? Are celibate dancers really that much of a threat to supersonic aircraft? ---
**Author:** ![Robot\_Arm](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/robot_arm/32/18280_2.png) [@Robot\_Arm](https://boards.straightdope.com/u/Robot_Arm)\ **Post date:** [July 31, 2010, 7:48am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/25 "2010-07-31T07:48:53Z")
> [@StrangerThanFiction](#): > > Off the top of my head, you’d want indicated airspeed, mach number, attitude, indicated altitude, radar altitude, rate of turn, heading, rate of climb, fuel quantities, fuel flows, fuel pressures, fuel temperatures, oil temperatures, oil pressures, engine speeds (N1), turbine temperatures, hydraulic pressures, electrical voltages and amperages, etc etc etc. > > Reading off that diagram I found compressor inlet pressures and temperatures, accelerometer, fuel tank pressures, spike position (engine inlets), and angle of attack. > > Considering many of those are doubled because there are two engines, I think we could pretty easily knock down 29 gauges. And that’s without mentioning the radios (comm and nav) or anything to do with the cameras. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [July 31, 2010, 7:54am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/26 "2010-07-31T07:54:59Z")
> [@panamajack](#): > > #18 - Shaker Indicator? > > Are celibate dancers really that much of a threat to supersonic aircraft? [It illuminates when the stick shaker activates.](http://www.sr-71.org/blackbird/manual/1/1-126.php) The stick shaker is a device that shakes the control column, warning of an impending stall. In light training aircraft stalling of the wings is typically preceded by a pronounced buffet which can be felt through the controls and airframe. If you ever feel this buffet it’s the first indication, often accompanied by an aural stall warning horn, that you are about to stall and you should reduce the angle of attack on the wing (normally by lowering the nose slightly, increasing power, and increasing airspeed.) If you ignore it the wing will probably stall and the nose of the aircraft will drop. You can still recover by relaxing any back pressure on the controls, lowering the nose, thereby reducing the angle of attack. That’s how it works on simple aircraft and it is what pilots are used to. On more complex aircraft the pre-stall buffet can be very subtle or non-existent. One of the minimum design features for an aircraft is that it must have adequate warning of a stall. When the airframe itself doesn’t provide the cues pilots are used to, artificial devices are used instead. The stick shaker is an artificial stall warning device that activates prior to the stall and imitates (and exaggerates) the pre-stall buffet through the control column. This is the pilot’s call to wake up, lower the nose slightly, and increase power and airspeed. On some aircraft the actual stall itself may be sufficiently dangerous that it should not be allowed to occur at all. These aircraft will have a stick pusher which pushes the control column forward thereby automatically lowering the nose so that the stall is avoided. The pusher normally activates after the shaker though if the angle of attack is increasing rapidly they may occur at the same time. The natural stalling characteristics of swept wing aircraft and T-tail aircraft are often less than satisfactory so stick pushers are common on commercial jets and sometimes fitted to T-tail turbo-props. The Colgan Dash 8 crash in Buffalo NY was ultimately caused by the pilot’s inappropriate response to the stick shaker and stick pusher. For some reason he pulled back on the column when the shaker activated, the pusher then activated and he continued pulling back against the pusher all the way to the ground. Edit: Reasons that no buffet is felt on complex/larger aircraft include the size, the placement of the tail plane relative to the main wing, and the use of hydraulic controls which prevent real feed-back from the controls surfaces to the control column. ---
**Author:** ![longPath](https://avatars.discourse-cdn.com/v4/letter/l/bb73d2/32.png) [@longPath](https://boards.straightdope.com/u/longPath)\ **Post date:** [July 31, 2010, 9:35am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/27 "2010-07-31T09:35:18Z")
quoted from above… [Here is a cockpit of a basic small plane without a glass cockpit and there are still many of those around.](http://en.wikipedia.org/wiki/File:Slingsby.t67c.panel.g-bocm.arp.jpg) > [@](#): > > The cockpit panel of a Slingsby T67C light aircraft (UK registration G-BOCM) at Kemble Airfield, Gloucestershire, England. > The basic T is visible: in a row there are Airspeed, Attitude (coloured blue) and Altitude. Below the blue Atttitude is the vertical “bar” of the T (the Heading). Does anyone know: Is the “Basic T” similar to what I learned to call the “Sacred 6”? ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [July 31, 2010, 11:00am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/28 "2010-07-31T11:00:35Z")
> [@longPath](#): > > quoted from above… > > [Here is a cockpit of a basic small plane without a glass cockpit and there are still many of those around.](http://en.wikipedia.org/wiki/File:Slingsby.t67c.panel.g-bocm.arp.jpg) > > > [@](#): > > > > The cockpit panel of a Slingsby T67C light aircraft (UK registration G-BOCM) at Kemble Airfield, Gloucestershire, England. > > The basic T is visible: in a row there are Airspeed, Attitude (coloured blue) and Altitude. Below the blue Atttitude is the vertical “bar” of the T (the Heading). > > Does anyone know: Is the “Basic T” similar to what I learned to call the “Sacred 6”? The sacred 6 is probably the same as the “six-pack” (reference to a “six-pack of beer”). The T is a subset of the six-pack which is airspeed indicator, attitude indicator, and altimeter across the top with the turn-coordinator, direct indicating compass, and vertical speed indicator across the bottom. They form the primary instruments used for instrument flying though you should be able to cope without the AI and VSI. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [July 31, 2010, 11:11am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/29 "2010-07-31T11:11:43Z")
Incidentally the bottom row on that Slingsby is, from left to right, a G-meter, a horizontal situation indicator (HSI), and an automatic direction finder (ADF). The G-meter has three needles, one showing the current G reading, and the other two showing maximum and minimum values since the last reset. The HSI is a heading indicator with a navigation overlay from either a VOR or an ILS and the ADF is a simple instrument that points a needle to a non-directional navigation beacon. You can combine the functions of the HSI and ADF and get rid of the heading indicator, that would make that cockpit a bit nicer for instrument flying. ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [July 31, 2010, 11:19am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/30 "2010-07-31T11:19:25Z")
> [@longPath](#): > > Does anyone know: Is the “Basic T” similar to what I learned to call the “Sacred 6”? By the way, the T is actually outlined in white in the B747 cockpit picture above. ---
**Author:** ![pilot141](https://avatars.discourse-cdn.com/v4/letter/p/e0b2c6/32.png) [@pilot141](https://boards.straightdope.com/u/pilot141)\ **Post date:** [July 31, 2010, 11:27am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/31 "2010-07-31T11:27:58Z")
Even way back in the 60s the designers had some things figured out! Today cockpits look much cleaner because we have the technology and the FAA has signed off on it to make everything much easier to read. But back in the day, they still tried! The engine gauges (the two stacks on the right) were set up so that you could quickly tell if there was a problem with one engine. You didn’t need to see that one gauge was out of tolerance - you needed to see that one gauge did not match the others. The other stuff was stuck where it could be, but with some thought. Hydraulics? Two separate systems, but at least the gauges are close! For a pilot, the worst thing is a LACK of information. I would rather have TOO MUCH info than not enough. Today the designers and the pilots work together, so that the info I want is the info I get, presented smartly by the displays. [An example.](http://www.flickr.com/photos/pilot141/4845583371/sizes/l/) Remember that we crashed a lot more airplanes in the 60s than we do today, and better instrumentation is one of the reasons. Of course, SR-71s weren’t flying into Hong Kong or JFK then, so you have that as well. In any case, that thing was a complex beast and I am glad that I never had to work it!! ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [July 31, 2010, 1:56pm UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/32 "2010-07-31T13:56:15Z")
> [@UncleBill](#): > > I LOVE that the airspeed indicator only goes to 5. MACH 5. Actually, the 5 on the airspeed indicator is 500 knots. The Mach meter is the small wedge inside the airpseed indicator. The markings under that wedge rotate to align the actual Mach number with the main pointer which points to the outer scale of knots indicated airspeed. **Pilot141** : Long time no read. How you likin’ the MD11? I flew the 717 for awhile which was the same avionics package except for a blank area where the center engine indicators had been. It was always a very nice place to work. Overall, the SR71 cockpit looks just like what it is/was: typical layout for a high performance aircraft of the era. Any of the Century series fighters or the F-4 look the same. As does the T-38. And the Navy’s A-3, A-4, A-5 & A-7. The A-6 had a weird TV screen for a central display, a forerunner of the EFIS systems of the 80s & later. But all of its peripheral gauages had the same look too. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [July 31, 2010, 3:09pm UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/33 "2010-07-31T15:09:14Z")
> [@DesertDog](#): > > When it passed the truck, a small object, presumably the film cartridge, would eject from the back and also arc up then hit the ground. Twin chutes would deploy while the truck scooted over to the cartridge, a guy jumped out to grab it and jumped back into the truck, which then shot off to parts unknown while the plane was still slowing down at the other end of the runway. Did they do that because: 1. To get the film delivered quickly 2. The airframe was too hot to get the film out manually 3. In case the aircraft had difficulties in landing they wouldn’t lose the film? ---
**Author:** ![pilot141](https://avatars.discourse-cdn.com/v4/letter/p/e0b2c6/32.png) [@pilot141](https://boards.straightdope.com/u/pilot141)\ **Post date:** [July 31, 2010, 5:52pm UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/34 "2010-07-31T17:52:10Z")
> [@LSLGuy](#): > > **Pilot141** : Long time no read. How you likin’ the MD11? I like the thing - not only the automation but also the trips. Leaving next week on an around-the-world trip, and I get to fly along L-888, an airway that goes over the Himalayas and can only be flown with CPDLC operational. The FMS on the -11 doesn’t look as fancy as some of the newer ones (it’s all green) but it sure is capable of some fancy stuff! We’ve got the Electronic Flight Bag on about 75% of the planes and the HUD on about 25% of them now, so it’s getting to be pretty high-tech. So, no complaints from me! ---
**Author:** ![Richard\_Pearse](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/richard_pearse/32/13144_2.png) [@Richard\_Pearse](https://boards.straightdope.com/u/Richard_Pearse)\ **Post date:** [July 31, 2010, 11:19pm UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/35 "2010-07-31T23:19:29Z")
I see a Lufthansa MD11 crashed recently after a cargo fire. Crew got out ok. ---
**Author:** ![sparky\_1](https://avatars.discourse-cdn.com/v4/letter/s/77aa72/32.png) [@sparky\_1](https://boards.straightdope.com/u/sparky_1)\ **Post date:** [August 1, 2010, 12:02am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/36 "2010-08-01T00:02:33Z")
> [@StrangerThanFiction](#): > > Here’s the B-36 flight engineer’s panel… one of my favorites 😉 > > [http://farm4.static.flickr.com/3498/3266721694\_f398d33cce.jpg](http://farm4.static.flickr.com/3498/3266721694_f398d33cce.jpg) Cockpit photos are so cool. I’d never read up on the B-36 before. The military tested one using nuclear propulsion!? Damn, to be alive in the 50s. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [August 1, 2010, 2:50am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/37 "2010-08-01T02:50:21Z")
> [@sparky\_1](#): > > > [@StrangerThanFiction](#): > > > > Here’s the B-36 flight engineer’s panel… one of my favorites 😉 > > > > [http://farm4.static.flickr.com/3498/3266721694\_f398d33cce.jpg](http://farm4.static.flickr.com/3498/3266721694_f398d33cce.jpg) > > Cockpit photos are so cool. I’d never read up on the B-36 before. The military tested one using nuclear propulsion!? Damn, to be alive in the 50s. No, unfortunately. The reactor did not contribute any power to the airplane, it was merely to perform basic research on such things as shielding and radiation dosage. Long story short, no reactor-powered plane could carry enough shielding to lift itself off the ground (at least if you wanted the crew to survive). There was talk of an unmanned remote controlled “tug” that could tow manned bombers at a safe distance, but the program got cancelled before they reached that stage. The B-36 is indeed cool; it’s a pity there are NO flyable B-36’s left. Apparently their design meant their engines, props and airframes took a heavy beating and they were all scrap by the end of their service lives. ---
**Author:** ![StrangerThanFiction](https://avatars.discourse-cdn.com/v4/letter/s/f05b48/32.png) [@StrangerThanFiction](https://boards.straightdope.com/u/StrangerThanFiction)\ **Post date:** [August 1, 2010, 2:53am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/38 "2010-08-01T02:53:48Z")
> [@LSLGuy](#): > > > [@UncleBill](#): > > > > I LOVE that the airspeed indicator only goes to 5. MACH 5. > > Actually, the 5 on the airspeed indicator is 500 knots. The Mach meter is the small wedge inside the airpseed indicator. The markings under that wedge rotate to align the actual Mach number with the main pointer which points to the outer scale of knots indicated airspeed. My favorite thing about the instrument panel is that the fuel flow gauges top out at 95,000 pph. Each. :eek: ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [August 1, 2010, 4:45am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/39 "2010-08-01T04:45:15Z")
> [@carnivorousplant](#): > > Did they do that because: > > 1. To get the film delivered quickly > 2. The airframe was too hot to get the film out manually > 3. In case the aircraft had difficulties in landing they wouldn’t lose the film? I have no idea, not having been in a position to ask questions without getting some pointed questions in return. I would guess mostly 1. Yes the skin would get awfully hot in flight but even if it had not cooled down by the time you got back and taxied to the hanger, you could eject the cartridge in the hanger if all you were worried about was burnt fingers. As for 3, I don’t recall hearing of any SR-71 crashes during the period – Yup, Wiki says they were four years into a seventeen year crash-free period at the time. ---
**Author:** ![carnivorousplant](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/carnivorousplant/32/3563_2.png) [@carnivorousplant](https://boards.straightdope.com/u/carnivorousplant)\ **Post date:** [August 1, 2010, 5:36am UTC](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641/40 "2010-08-01T05:36:29Z")
> [@DesertDog](#): > > I have no idea, not having been in a position to ask questions without getting some pointed questions in return. I would guess mostly 1. Thanks, my favorite aircraft of all time after the [YF-12A.](http://en.wikipedia.org/wiki/Lockheed_YF-12) The Gotterdammerung interceptor, carrying a nuclear missile to shoot down squadrons of Russian bombers over Canada. [Previous page](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641.md?page=1) [Next page](https://boards.straightdope.com/t/what-are-all-those-dials-on-the-sr-71-blackbird-for/548641.md?page=3)