by "ttyymmnn" (ttyymmnn)
Published 11/30/2017 at 15:33
by "ttyymmnn" (ttyymmnn)
Published 11/30/2017 at 15:33
Tags: Planelopnik
STARS: 10
While searching for information on the B-52, I came across a
forum
where the following question was asked:
Does anyone know what the take off field length is for the B-52 at MTOW. Also, needing landing distances.
Seems like a simple question. Not so fast....
B-52 takeoff distance (S2 distance) is a function of brake release gross weight, pressure altitude, OAT (outside air temperature), and EPR (engine pressure ratio) used for takeoff (either TRT (takeoff rated thrust) or partial thrust). Furthermore, takeoff distance will be affected by winds (however a headwind, which would shorten takeoff distance, is disregarded for planning purposes and a tailwind (downwind takeoff) is to be avoided), runway gradient (takeoff distance is longer going uphill), and runway surface (water and slush standing on the runway will extend the ground run). Assuming flaps down, 8 engines, a 200 foot line-up distance and no wind, a maxed-out B-52H (488,000lbs brake release gross weight) at 500 feet pressure altitude, OAT of 60 degrees F and using TRT of 1.71 EPR on a level, dry runway should have a takeoff ground run of approximately 8000 feet. Under the same conditions except using partial thrust of 1.67 EPR, the ground run increases to approximately 8600 feet. For landing, landing ground run is a function of gross weight (which determines the speed flown on final), pressure altitude, OAT and RCR (runway condition reading). Also, winds, pilot braking technique, drag chute employment and airbrake position will affect landing ground run. All landings are planned assuming full flaps, no drag chute, 8 engines at idle, full airbrakes at touchdown and wheel brakes applied at touchdown speed minus 20 knots. Under these assumptions, a 270,000lb B-52H, using a best flare speed of 135 knots at airbrakes 4, pressure altitude of 500 feet, OAT of 60 degrees F and RCR of 23 (dry runway), no wind, no gradient, would have a planned landing ground run of approximately 4900 feet. Under normal landing conditions (drag chute deployed at touchdown, wheel brakes at 90 knots), all other conditions the same, the ground run drops to approximately 4100 feet. The previous figures do not include landing flare distance, which, under these conditions, would be approximately 3300 feet. I can give you TOLD for a G model also if you want that.
"RamblinRover Luxury-Yacht" (ramblininexile)
11/30/2017 at 15:37, STARS: 1
I like.
"Ash78, voting early and often" (ash78)
11/30/2017 at 15:40, STARS: 5
I can’t imagine a frame of mind that would result in an answer like that, assuming the tone and depth of the original question is an indication of the type of answer requested.
Hypothesis: the back end of an all-night meth bender.
"user314" (user314)
11/30/2017 at 15:42, STARS: 9
Hah! I knew this book would come in handy!
"My hovercraft is full of eels" (my-hovercraft-is-full-of-eels)
11/30/2017 at 15:42, STARS: 1
I already knew that.
"ttyymmnn" (ttyymmnn)
11/30/2017 at 15:45, STARS: 4
In case there’s something that Haynes left out....
"ttyymmnn" (ttyymmnn)
11/30/2017 at 15:47, STARS: 4
Somebody who really wanted to show off what they knew; a Buff pilot who wanted to express just how complex a task it really is; somebody who is just really into giving complete answers.
Either way, I find it a fascinating look at just how complicated it is to fly a plane, especially one that is 65 years old.
"BeaterGT" (beatergt)
11/30/2017 at 15:50, STARS: 4
I love little hearths of knowledge like this. When I ask about aero in F1, nothing makes me happier than getting a well thought out, heavily-detailed response.
"ttyymmnn" (ttyymmnn)
11/30/2017 at 15:51, STARS: 0
“little hearths of knowledge”
I like that. Great imagery.
"Yowen - not necessarily not spaghetti and meatballs" (yowen)
11/30/2017 at 15:57, STARS: 2
This is most definitely the kinder hypothesis!
"Ash78, voting early and often" (ash78)
11/30/2017 at 16:02, STARS: 3
Interestingly enough, it reminded me of how my dad answers questions. Yes, he’s a lifelong engineer and pilot. Everything comes with a degree of precision, to put it lightly. Even when you’re making it up.
"ttyymmnn" (ttyymmnn)
11/30/2017 at 16:04, STARS: 5
Whenever my boys ask me questions about history in general, or WWII in particular, they always get very long answers. Because there is no history without context.
"415s30 W123TSXWaggoIIIIIIo ( •_•))°)" (415s30)
11/30/2017 at 16:10, STARS: 1
So.....maths?
"valis86" (valis86)
11/30/2017 at 16:19, STARS: 0
Nah, just an engineer. My Dad worked at Rockwell and Lockheed/Martin, and I’ve met a few of those ‘people’. Best was a guy who built his own airplane over the course of a decade from scratch. They are just wired VERY different.
That guy may have been the worst golfer I’ve ever met. Definitely was the worst driver.
"ADabOfOppo; Gone Plaid (Instructables Can Be Confusable)" (adabofoppo)
11/30/2017 at 16:30, STARS: 2
I have a BA in History; I don’t use it anymore but that’s beside the point I am trying to make.
While in college for said degree, I was taking a ‘Leadership’ class for this school’s group of students selected as ‘leaders’ based on their high school grades and performance. I was forever amazed when the class was discussing various forms of leadership throughout US history how no one else in the class could connect current events for the leader(s) being discussed and how those events affected their tenure in their position and overall leadership style; context. Inevitably since no one else would answer, I felt I had to, which always lead to lots of eyes rolling as I went on another ‘tangent’. I am still shocked at how ignorant people are about how much history shapes everything we do.
This post is not to serve as any humble-brag. I was indeed very good at school, but that does not mean I am smarter than any one else. Only that I enjoy a classroom learning environment and was able to maintain that skill and succeed at taking classes in college as well. I am not, however, good at using my hands to so things myself. I can barely change my own oil or rotate tires quickly. Asking me to build something other than IKEA is impossible. There is more to intelligence than being good at school.
That said, everyone should be more aware of how stupid people are as a species. We have been doing the same dumbass shit since the day we walked upright, and we clearly aren’t learning anything from our previous mistakes.
"ttyymmnn" (ttyymmnn)
11/30/2017 at 16:31, STARS: 3
My wife works in the school of engineering at a large public university. We go to the Christmas party every year (free food and booze), and I always marvel at the large collection of socially inept people.
"Chariotoflove" (chariotoflove)
11/30/2017 at 16:31, STARS: 1
Holy cow. I have a sudden urge to buy this person a beer.
Also,
Does anyone know what the take off field length is for the B-52 at MTOW. Also, needing landing distances.
Who needs this? He should have added, “asking for a friend”.
"ttyymmnn" (ttyymmnn)
11/30/2017 at 16:32, STARS: 1
Lots and lots of maths. And sometimes, they get the maths wrong .
"ttyymmnn" (ttyymmnn)
11/30/2017 at 16:32, STARS: 1
I loaned him the DVDs of both films. He watched them both, and said, “Meh.”
I’m guessing the guy needed it for some flight sim. Or he was a Russian agent. Hard to be sure.
"Chariotoflove" (chariotoflove)
11/30/2017 at 16:38, STARS: 2
I’d buy time on a B-52 flight sim.
"user314" (user314)
11/30/2017 at 16:39, STARS: 0
I have the one for the F-82 as well
"ttyymmnn" (ttyymmnn)
11/30/2017 at 17:02, STARS: 2
That’s cool. Finally saw one of those up close at Dayton last summer, and not just any F-82, but the Betty Jo , which flew non-stop from Hawaii to New York, a distance of 5,051 miles.
"ttyymmnn" (ttyymmnn)
11/30/2017 at 17:04, STARS: 2
Me too. That would be fun. Pretty sure I’d crash it, though.
"Chariotoflove" (chariotoflove)
11/30/2017 at 17:05, STARS: 3
Isn’t that what sims are for?
"ttyymmnn" (ttyymmnn)
11/30/2017 at 17:05, STARS: 0
Yeah, pretty much. I suppose flying from A to B would get pretty boring after awhile.
"Chariotoflove" (chariotoflove)
11/30/2017 at 17:07, STARS: 1
Unless you get to drop bombs.
"ttyymmnn" (ttyymmnn)
11/30/2017 at 17:22, STARS: 6
I was at an air show a few weeks ago, and had a long, fascinating conversation with a USAF F-35 pilot. We talked about his plane, but we also talked about policy, military history, world history, the possibility of WWIII. The pilot said something that resonated with me: History never repeats itself, but it does rhyme.
"415s30 W123TSXWaggoIIIIIIo ( •_•))°)" (415s30)
11/30/2017 at 17:24, STARS: 0
Yeah for sure, my dad flew jets in Nam and he would always do fuel calculations in his head, try and quiz me. I am not like that!
"user314" (user314)
11/30/2017 at 17:24, STARS: 1
I got my copy from the USAFM gift shop, as a matter of fact. It’s probably for the best I was limited to only books, as I was flying back. I could have spent a lot of money otherwise.
"user314" (user314)
11/30/2017 at 17:27, STARS: 2
I think I might just have to remember that, it’s a really good turn of phrase.
"ttyymmnn" (ttyymmnn)
11/30/2017 at 17:28, STARS: 2
I could have spent lots of money (mostly on books), but the only thing I bought was this tie for my brother.
"ttyymmnn" (ttyymmnn)
11/30/2017 at 17:30, STARS: 2
It’s an excellent turn of phrase. This guy was really squared away. Very contemplative, knowledgable (as you would expect from a USAFA grad), quiet. Just the kind of guy you would want in a fighter a complex as the F-35. Contrast him with the F-22 driver I talked to briefly who was a cocksure fighter jock, full of himself and his airplane. I could have talked to the F-35 driver for hours.
"ThePenguin" (ThatOtherGuy7)
11/30/2017 at 19:42, STARS: 0
Well why don’t you calculate it yourself then?!?
"valis86" (valis86)
12/01/2017 at 13:08, STARS: 1
I grew up nearthe USAFA, baby sis got married to a zoomie at the Chapel there, and he ended up flying the F16 for 26 years. I know EXACTLY what you mean. When I saw him over Turkey Day and asked him his views on Trump the response I got was ‘he is raising the discussion on many topics that need addressing and that is good’
Easily the most eloquent non-answer Ive ever received.