Talk:Boeing KC-135 Stratotanker

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I was going back through some of my old photos from 25 years ago and found I have a picture of 55-3136, which is listed on various websites as a JKC-135A. Any idea what that is? Nothing I've seen answers it sufficiently except that it was some kind of test aircraft. -Rolypolyman (talk) 20:02, 14 November 2009 (UTC)

I have 55-3136 first flown 13 Aug 1957 and used in experiments to determine the effects of Aurora Borealis on radio communuications between 1957 and 58 for which it had an addition spinal antenna. It was later used in the nuclear weapon test program until it was returned to SAC in May 66. MilborneOne (talk) 21:15, 14 November 2009 (UTC)
Let me google that for you...
However, to answer your question:
King Hawes writes:
Tail number 59-1491 started out as a KC-135A and was delivered to Wright-Patterson AFB on Oct. 1, 1960 for conversion to a JKC-135A named "Nancy Rae".
After modifications, Nancy Rae deployed to Shemya on New Years Eve 1961 to record Soviet ICBM launches into the Kamchatka peninsula.
On March 1, 1963 Nancy Rae was transferred from AFSC to SAC and was converted by General Dynamics to an RC-135S (First of its kind) and renamed "Wanda Belle". The name "Wanda Belle" was changed to "Rivet Ball" in early 1967. Rivet Ball crash landed (January 13, 1969) on Shemya after returning from an operational mission.
Rivet Ball (Tail #59-1491) never flew again. Her remains ended up in the "Million Dollar Dump".
It would not surprise me to find out that the airframe you listed was one of those converted to an RC-135 variant. — BQZip01 — talk 21:21, 14 November 2009 (UTC)
Sorry to dissapoint but after test use it went into service as a tanker with the 917th ARS/96th Wing until it went to Davis-Monthan for storage in April 1993. MilborneOne (talk) 21:26, 14 November 2009 (UTC)
Interesting... the reason I asked is I have a picture of 55-3136, when it was a transient bird at Clark Air Base sometime around late 1981 and was parked on the MAC ramp. Apparently it was doing regular old tanker duty and was on a deployment, at least from what I can tell. -Rolypolyman (talk) 01:50, 13 January 2010 (UTC)
I could have been more clear; my comments were about the JKC-135A, not the mentioned tail number. — BQZip01 — talk 00:08, 14 January 2010 (UTC)

Similarity to 707[edit]

The 707 and KC-135 share an awful lot, remarkably similar by a reasonable standard, since they share the -80 as a "parent." Consider that they have virtually identical wingspans, heights, and lengths, were originally equipped with the same engines, and share muscle-powered servo tab flight controls (an uncommon configuration in aircraft of this size). They have virtually identical profiles (save the 135's boom), so similar that a layman can immediately pick them out as twins. The size difference is very small, really noticeable only in fuselage diameter (since the 707 carried people and baggage, who need more space than fuel.) The differences are a matter of tweaks here and there, and the family resemblance is overwhelming. What differences would you point to? (talk) 22:20, 23 August 2010 (UTC)

The size difference is so tiny as to be insignificant. They're closer in size to each other than to the prototype 367-80. We're talking about an increase of about 4 inches from -135 to 707. Both are more than a foot bigger than the -80. Using the word "larger" really puts the wrong image in your head. They were contemporaries, and virtual twins. Calling out the differences should be left to the body of the article; the intro gives it undue prominence. (talk) 22:35, 23 August 2010 (UTC)
It depends on if you think a 10 ft increase in length would makes the 707 larger. MilborneOne (talk) 19:45, 24 August 2010 (UTC)

The FAA considers them quite similar, at least operationally.The Federal Aviation Regulations (FAR's) Part 61.73 — Military pilots or former military pilots: Special rules. will grant a KC-135A or Q aircraft commander a Boeing 707/720 type rating. Don't know what the reengined R model equates to. Don't know if ANY 707's are still in operation anywhere in the world, so the question is largely moot now. But that's how I got the type rating on my pilot's certificate.Dwalexmd (talk) 18:25, 23 October 2014 (UTC)

Payload/Maximum Fuel Load[edit]

According to the General Characteristics, the Payload is 83,000 lb (37,600 kg); at the same time, the article says that the "Maximum Fuel Load" is 31,275 US gal (118 kL). How can this be? 118.000 l Jet fuel should weigh more than 37.600kg? —Preceding unsigned comment added by (talk) 19:14, 28 October 2010 (UTC)

Also, for the KC-46A, the fuel capacity is given in lbs and kg, while for the KC-135 it is given in gals and cubic meters. These need to be made consistent. Either volume or weight or both, but not one for one plane the other for another. peter (talk) 18:24, 20 August 2012 (UTC)

WP:sofixit? Nothing is stopping you from making these alterations. Do you need assistance as to how to do so? Buffs (talk) 01:30, 21 August 2012 (UTC)

Operator image[edit]

Please excuse me if this is the wrong place. The picture of the view from the boom operators view seems to be from a KC-10 tanker where the boom operator sits upright. On KC-135's the boom operator lays on his stomach. —Preceding unsigned comment added by (talk) 00:45, 1 March 2011 (UTC)

I believe it is the camera angle that makes it appear as those the boom operator here is seated. I looked at some similar images on and found a similar image that make it clear the operator is in a prone position. -Fnlayson (talk) 05:03, 1 March 2011 (UTC)
It's the camera angle. Note the chin rest, and the distinctive KC-135 boom. — Preceding unsigned comment added by (talk) 01:33, 10 January 2012 (UTC)

Sale to Israel?[edit]

Even Reuters is talking KC-135 rather than KC-130Js. Are we really going to sell aircraft that are almost as old as Israel? Hcobb (talk) 14:41, 22 April 2013 (UTC)

I am not sure who we are, as Israel has some really old 707s converted to tankers a few fairly recently refurbished and re-engined KC-135s would be a good deal. But like all these things we will just wait and see what if any agreement is made. MilborneOne (talk) 18:17, 22 April 2013 (UTC)

1987 Crash at Fairchild[edit]

According to the Fairchild Air Force Base page, there was a crash there in 1987:

"On 13 March 1987, a KC-135A crashed into a field adjacent to the 92nd Bomb Wing headquarters and the taxiway during a practice flight for an In-Flight Refueling Demonstration planned for later in that month. Seven were killed in the crash, six aboard the aircraft and one on the ground."

Can someone source this information? — Preceding unsigned comment added by (talk) 20:07, 3 May 2013 (UTC)

PDF rendering Error[edit]

When I try to download this page as a PDF it keeps saying "WARNING: Article could not be rendered - ouputting plain text. Potential causes of the problem are: (a) a bug in the pdf-writer software (b) problematic Mediawiki markup (c) table is too wide" How can this problem be fixed? American Writer (talk) 00:27, 1 February 2014 (UTC)

когда я пытаюсь загрузить эту страницу как PDF-он продолжает говорить, что "предупреждение: статья не может быть вынесено - ouputting обычный текст. Возможные причины проблемы: а) ошибка в pdf-writer software (б) проблемные разметки Mediawiki (c) Таблица слишком широкая" как можно эту проблему исправить? американский писатель (обсуждение) 00:27, 1 февраля 2014 (UTC)

Numbers don't add up[edit]

"is 96% quieter than the KC-135A (sideline noise levels at takeoff were reduced from 126 to 99 decibels)". 96% reduction of noise from 126 decibels is 5.4dB. I doubt there is even a machine to measure this tiny level of noise. 126 to 99dB reduction is just over 20%. Could someone check and correct? Or explain why I'm wrong? Le Grand Bleu (talk) 14:11, 12 July 2014 (UTC)

The Decibel scale is logarithmic, where
  • dB=10\cdot\log_{10} x
  • x is the power of the sound
  • \sqrt{x} is the amplitude of the sound
In this case,
     126dB=10\cdot\log_{10} (3.98\times{10^{12}})
     99dB=10\cdot\log_{10} (7.94\times{10^{9}})
 so the ratio of amplitudes is
     \sqrt{\frac{7.94\times{10^{9}}}{3.98\times{10^{12}}}} = 0.045
Thus the noise (i.e. sound amplitude) is reduced by 1-0.045 = 95.5% in going from 126dB to 99dB. Mliu92 (talk) 19:17, 21 October 2014 (UTC)
There must be something wrong here. Why is 126dB a 1? And why 0.045 is a percentage if it's the result of a square root? Since when the result of a square root is percentage? And why all of a sudden, to find a fraction one number is of another, you devide one number by the other and then take a square root out of that? Le Grand Bleu (talk) 21:13, 21 October 2014 (UTC)
Sorry, I didn't explain very well. Based on the definition of the decibel scale, 3.98\times{10^{12}} is the power of the noise at 126dB, and similarly, 7.94\times{10^{9}} is the power of the noise at 99dB. The actual volume of the noise is based on the amplitude, though, so that's why you take the square root. \sqrt{3.98\times{10^{12}}}=2.00\times{10^{6}} is the amplitude of the 126dB noise, and \sqrt{7.94\times{10^{9}}}=89.1\times{10^{3}} is the amplitude of the 99dB noise.

If you then subtract 95.5% of 2.00\times{10^{6}} (the amplitude of the 126dB noise) from 2.00\times{10^{6}}, i.e., (1-0.955)*(126dB noise amplitude), you end up with 89.1\times{10^{3}} (the amplitude of the 99dB noise)=0.045*(126dB noise amplitude).

What I had written above was determining how large the amplitude of a 99dB noise is compared to the amplitude of a 126dB noise. Since both the numerator and denominator of the fraction are being taken to the square root, I divided before taking the root. \sqrt{\frac{7.94\times{10^{9}}}{3.98\times{10^{12}}}} = \frac{\sqrt{7.94\times{10^{9}}}}{\sqrt{3.98\times{10^{12}}}} = \frac{89.1\times{10^{3}}}{2.00\times{10^{6}}} = 0.045. This means 89.1\times{10^{3}} is only 4.5% of 2.00\times{10^{6}}. Hence the amplitude of a 99dB noise is only 4.5% of the amplitude of a 126dB noise, or to flip the fraction around, 99dB represents a 95.5% (=100% - 4.5%) reduction in amplitude compared to 126dB. 126dB is the 1 (or 100%) because that's the quantity you're comparing the 99dB noise against. Mliu92 (talk) 22:30, 21 October 2014 (UTC)
I'll need to investigate this further or ask someone. It just doesn't make sense. Physical laws always do! 126 decibels is very loud, so is 99 db. It CANNOT be that slight reduction is 95%. However you put it, 95% is almost the whole thing. Your explanation doesn't explain this. If it's true, then there must be another explanation or a mistake in what you're saying. Should probably ask at the aviation portal. This CANNOT be true. It just doesn't make sense. Le Grand Bleu (talk) 11:20, 29 October 2014 (UTC)
I agree the decibel scale can be confusing. The math shows 99dB does represent a 96% reduction in sound amplitude compared to 126dB, but decibels are difficult to understand intuitively. The Sound pressure article gives a few examples of sounds and their decibel levels; in the first table, there are entries for a jet engine at 1m (150dB) and a jet engine at 100m (110-140dB). Let's take the lower end of the scale and say the jet engine at 100m is 110dB.

Intuitively, we know the sound will fall off the farther away we are from the engine. So it's reasonable to think that at 100m away, the sound of the engine is much quieter. Back to decibels, then: how much quieter is 110dB compared to 150dB? It is a 40dB reduction in noise, or \frac{40}{150}=26.7% less than 150dB using the decibels alone. But you know that at a distance of 100m, the jet engine isn't just 27% quieter than it would be if you were 1m away from it. At 100m away from a jet engine, you would probably be able to carry on a conversation, albeit in a loud voice. At 1m away, if you're not wearing headsets and microphones, you'd be using sign language if not actually crawling away in pain.

Back to the math of decibels, then. N dB=10\cdot\log_{10} x, as before. We can rewrite this to solve for power as x={10}^{(\frac{N}{10})}. The power of a 150dB noise is:
    {10}^{(\frac{150 dB}{10})}=1.00\times{10}^{15}

Similarly, the power of the 110dB noise is:
    {10}^{(\frac{110 dB}{10})}=1.00\times{10}^{11}

Compare the amplitudes of the two noises (by taking the square root), and the 110dB noise is just 1% of the 150dB noise:

In other words, the 110dB noise actually represents a reduction of 99% (not 27%) in sound pressure compared to the 150dB noise. I agree, 110dB and 150dB are both still quite loud, but 110dB is markedly quieter than 150dB. Intuitively, decibels are akin to the exponent in scientific notation.

Let's say I created a new temperature scale and called it "KelvinExponent" by defining y^{\circ}KE=\log_{10} z K, where y is "degrees KelvinExponent" and z is the temperature in Kelvin, so 2°KE=100 K (i.e., 1\times{10}^{2}K) and 1°KE=10 K {1\times{10}^{1}K}. This would, by the way, be a terrible temperature scale. You recognize that the reduction in temperature is 90 K when going from 2°KE to 1°KE. Instead of saying that the temperature is reduced by 50% (1°KE is only half of 2°KE) because that's how you compute it with the KelvinExponent scale, it's more accurate to say the temperature is reduced by 90% (10 K versus 100 K). Decibels work in much the same way, it's a logarithmic scale because of the sheer range of sound pressures possible (and detectable to the human ear). Mliu92 (talk) 16:45, 29 October 2014 (UTC)
Okay, let's test your theory. If decrease from 126 to 99 dB is 96%, how much would be a reduction from 126 to 40dB? Can you use your formula for this calculation? Le Grand Bleu (talk) 14:23, 5 December 2014 (UTC)
Sorry for the late reply. The decibel formula is:
   dB=10\cdot\log_{10} x
   126dB=10\cdot\log_{10} (3.98\times{10^{12}})
   40dB=10\cdot\log_{10} (1.00\times{10^{4}})
   \sqrt{\frac{1.00\times{10^{4}}}{3.98\times{10^{12}}}} = 0.000050, so the 40dB sound is only 0.005% the amplitude of the 126dB sound, it represents a 99.995% reduction in amplitude compared to the 126dB sound. Going back to the examples given for various real-world sounds compared to their decibel levels, 40dB describes a normal conversation at 1m, while 120dB describes a vuvuzela at 1m. — Preceding unsigned comment added by Mliu92 (talkcontribs) 06:31, 5 March 2015 (UTC)