critical ME

Slip n Slide

2008-08-20T16:37:00.000-07:00

Cookies if you know what's happening in this picture.

Hint: Not a slipNslide.

_ttk3

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Now playing: Zao - The Last Song From Zion
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Formula Fail

2008-08-10T18:18:00.000-07:00

[insert explicit here]

The 2008 season was a bitter experience for the RIT FSAE Racing Team. After showing up in Detroit with a solid and sorted car, a radiator cap failure led to a DNF in the endurance race, knocking the team out of a predicted podium finish and all the way to 27th place.

Last week the team arrived in Germany with high hopes of kicking European ass. Bringing with them lessons learned from Detroit and the experience of an additional month of testing and driver training, their hopes looked to be fulfilled. After a 3rd in acceleration, a 2nd in cost events and a 4th overall in autoX, the team headed to the endurance race grid with cautious confidence. They were poised for another top finish but it would not transpire.

Five laps into the second driver's 11-lap stint and the car shut down, ending the competition with another DNF. Preliminary diagnosis of the problem points to the fuel system. The team plummeted to 26th place.

As a member of the team, I feel as though I have been stabbed several times and I didn't even attend the races. It goes without saying that the team has out forth tremendous effort and all members should be proud of the accomplishments of the past year:

- A new chassis; its light, its fast, its solid and it wasn't a problem (once we got it built!). Now it's up to The Hammer to sort out the bugs and please, no geometry-class jigs this year.

- Redesigned braking system; lighter, stronger and easier to manufacture. This group isn't slowing down. Good luck to Double D getting it done for next year.

What does the team have on tap for next year? Given the competitive nature of FSAE, any advances will be under wraps until next May. Hint: It's all about DA FLOWS!

Charles explains why the team was tearing into the car the day of tech inspection: Video

_ttk3

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Now playing: Lamb of God - Foot to the Throat
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Youtube Rant #1

2008-08-01T13:31:00.000-07:00

ballistic video...

...but the comments will blow you away!

Seriously, youtube causes me so much vexation. I can't believe that so many people think that they have to comment on videos, just to share their innate knowledge of the topic at hand. Need proof? What follows are the best comments, I couldn't make these up.

Deadskull75: the wave your talking about happened because it was about to break the sound barrier which is 1000mph

NO WAYS REALLY?! 1000mph MAN! You couldn't just do one Google search for the speed of sound?? Next time you feel the urge to spread you're deluded crap, STOP and take a breath. Think, is what I am about to share with the world actually correct? If there is any doubt, google is only a few strokes away.
_____
Richona: Im sure it would provide some benefits, whilst maybe not being the best method of penetration. And about it wanting to hit straight on, it would need to be perpendicular to the armor for that to be effective dont you think? With todays slanted armor, that might prove tough. But what do I know haha!

HAHA Exactly. gtfo.
_____
gamergeek2008: it was cuting through the air at the end look in front of the bullet!

As opposed to what? The beginning?
_____

and in conclusion;

LizzyAston: I would like that dildo shot up my ass, please.

_ttk3

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Now playing: August Burns Red - Up Against The Ropes
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GAU4PCE

2008-07-11T13:44:00.000-07:00

You may have seen this floating around, but it is worth reading again, especially in this election year.
___________
...He asked, ‘ Do you know how to catch wild pigs?’ The professor thought it was a joke and asked for the punch line. The young man said this was no joke. ‘You catch wild pigs by finding a suitable place in the woods and putting corn on the ground. The pigs find it and begin to come everyday to eat the free corn. When they are used to coming every day, you put a fence down one side of the place where they are used to coming. When they get used to the fence, they begin to eat the corn again and you put up another side of the fence. They get used to that and start to eat again. You continue until you have all four sides of the fence up with a gate in the last side. The pigs, who are used to the free corn, start to come through the gate to eat, you slam the gate on them and catch the whole herd. Suddenly the wild pigs have lost their freedom. They run around and around inside the fence, but they are caught. Soon they go back to eating the free corn. They are so used to it that they have forgotten how to forage in the woods for themselves, so they accept their captivity.
__________

I took the liberty of removing the intro and the conclusion to the above parable in the hopes that one wouldn't need it spelled out.

In other news, best license plate idea ever: GAU4PCE. Only slightly behind GLBLWMR. My creativity never ceases to amaze me...

_ttk3

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Now playing: Primus - Fish On On (Fisherman Chronicles, Chapter II)
via FoxyTunes

super real world problem solving example (not found in the DME book)

2008-05-28T18:13:00.000-07:00

Locked my keys in the car today at work. EVERYBODY PANIC!

Ha...no. I'm not what you would call 'busy' at EB as a summer hire so I had plenty of time to figure out how I was going to break back in. My first idea was the common coat hanger. Unfortunately EB has no normal coat hangers on site. Believe me, I looked in about four different buildings. Fortunately, my get-shit-done engineering prowess let me to discover my fellow specialists occupied hanger folders.

A quick jaunt upstairs and a moment desperate pleading with our AA landed me my very own hanger folder. Some rough surgery with the mini my tighe, scotch tape patches and BAM homemade slim jim. Now, you ever felt awkward before? Like, 'man I really out of place here,' awkward? Try walking through parking lots with an obviously illicit tool. Whatever, it got the job done and now it's now perched above my desk. Maybe I can turn a profit renting it out to other morons in my position.

In conclusion, I would like to thank EB office supply budget! Without you this ingenious solution would have never come to fruition. You may not pay me for observed national holidays, but you saved me a locksmith on this one.

Rally Civic: Round 2

2008-03-30T17:48:00.000-07:00

New lights for the civic going on soon. I got out the compass and some scrap paper to mock up the new lenses. I plan on running higher speed classes at next seasons rally's, weather permitting. I'm thinking novice class when it's really nasty and bump it up to 40mph class when the weather is boring. As an added bonus, I can now blind those asshats who pass me (racecar engineer speaking).

In anticipation of summer autocross's, Falken 615's are going on my steelies for the summer. Heavy? Not when they have all those lightening holes in them... You're not going to convince me I need race wheels.

And the Kona? Bought a rack for that today (<3 craigslist) so I'll be touring CT all summer.

And there we have it. Trying to do everything I can to get away from Groton on the weekends. More updates and a polished piece on how I dumped over 2 cases of premix oil into the atmosphere, coming soon.

_ttk3

some day....

2008-01-31T22:53:00.000-08:00

I walk out of my back door down a small stone path across the fresh cut grass. Insert a key into the lock, twist, open....shut the door behind myself. A flip of 2 switches and a few 40amp breakers turns on overhead lighting, a radio, and other electron thirsty circuits. I set down a warm cup of coffee next to a big blue box resembling a Cold War era missile launch panel and grab a black mask with a seemingly opaque lens in the middle of it. A few more switches to flip, a big knob sitting on top of 80lbs of inert gas to turn and I flip down my mask with a smooth jerk of the neck. I press forward on the big sewing machine pedal sitting on the floor. After 1 more coffee refill, 3 hours of time, and 2 minor burns on the ball of my hand, I'm finished welding up a day's worth of goodies for installing.

I turn around on my stool to look at 6000lbs of 4130 tubing, cold rolled skid plates and dual shocks hanging corner. A project truck by all means, but a capable off-road vehicle - built in my back yard. Another sip of the coffee just to realize its again reached the bottom layer of sludge in the cup.

A quick break from the ozone/ burning impurities filled air leads me up a small staircase to a dim lit room with the sound of hard drives spinning and monitors humming. A small switch on the side of a large custom built desk (yes, I do a bit of carpentry too) sends a wake up call to 4 nicely proportioned LCD displays. On 2 displays are 3D cad drawings of parts currently being built, and others being conceived. Another display dedicated to email, web browsing and chatting with Mom online, with the 4th left for a full screen deadline counter. It reads 26:10:36. 26 days left to finish the beast below and still have ample test/tune time if it is to set for it's maiden voyage down the Baja peninsula. 26 days sounds like a ways off but behind the desk on the wall hangs a large white board covered in a to do list - each task having its own deadline.

After a few phone calls looking for parts apparently lost in the mail, and a few more looking for ideal shock valving setups and its time for lunch. A leftover burrito in the minifridge from Lolita's gets some microwave injection followed by a little hot sauce. Who ever thought French fries in the burrito would be so damn good? A brief check of the weather channel and current NYSE situation on the nice TV hanging on the wall mixed with a few gory images of war and world starvation means its time to get back to work.

Mount up the roof rack and light mounts welded up earlier in the morning and check their fit. Confirming their placement, I attach a masking tape label and move them to the "flat back krylon" pile in the room adjacent to where the truck is located. I check on the condition of another set of parts painted yesterday and decide that an extra coat might be necessary to protect against the harsh desert conditions.

I switch gears and do some electrical work, after being confident in the location of all accessories. Fuel pump, gauges, radio, GPS, air purification pumps, fuel pump, starter button, and enough lights to light up the sky over Mexico like the space ship from ET.

Feeling the effects from lunch and noticing the onset of night, I feel the need to get ready for a busy 2 weeks. Did I mention that the 26 days remaining include 3 50+ hour work weeks? Oh well, I guess that's what crunch time with the help of friends is for.

Climbing into bed, I feel a sense of pride in having created such a beast in my own back yard. I anticipate the neighbor's thoughts upon the initial startup of the 600hp big block but figure they'll get over it soon thereafter. Sleep brings another day.

25:23:56

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Now playing: Grace Potter and the Nocturnals - gpn2007-08-19d1t12
via FoxyTunes

The Lost Art of Getting There

2008-01-31T00:53:00.000-08:00

"SHARP right at 1.23 miles." States Baldi, punching numbers into the calculator. My odometer reads 1.0. I give a quick glance into to my right to view the tulip diagram to give me an idea of what I'm driving towards. The ghetto diagram looks like it was made in MS Paint but they get the job done.

"You have 30 seconds to get through. Better bump it up to 45mph."

"Yeah, well..." I trail off, all my concentration on the road ahead of me. I barely remember anything he just said. I know that I'm going too slow, barely doing 35mph and my average speed class is 36. It's black outside and I can only see about 100 feet in front of me, my view limited by snowflakes the size of quarters driving against my headlight pattern. I try to increase my speed, but the best I can manage is just above 40. Baldi adds,

"There's a quick left 0.12 after the turn, ignore the 'ROAD CLOSED' sign."

The "road" we are barreling down is approximately 6 inches of snow covering gravel. The Civic is jumping from one set of Subaru ruts to the next, by the time it settles down, I start to see the turn up a head. DAMN! It is sharp!

"Shhhiiiii..." I udder, quickly but fluently jumping onto the brakes. The tires immediately lock. I feather the pedal trying to keep the car straight. As the tires shudder over the snow, Baldi looks up from the route map, suddenly aware of the critical situation and quickly grabs the door handle. (HA! like that's going to help.)

About 100 ft off the turn and the car is still doing about 20. Dunlop did not design my all-season tires for this much snow. There is no way in hell I'm making this turn unless I get some not-learned-in-class physics help. I see a little rut off the inside of the turn and start to coerce the inside track into it. I feel a satisfying jolt as the wheels fall off the edge of the road, into deeper snow. I quickly get on the gas, but only enough to keep power to the wheels. If I spin them, I jump the rut and classroom physics takes over, sending me into the outside tree line. With some reserved throttle, I'm through and reaching over the steering wheel to reset my odometer while simultaneously tracking out from the turn, sliding back in the scooby ruts.

"There it is!"

I don't even get my finger off the odometer as Baldi yells. Still tracking out, I try to get back to the other side of the road but horrid understeer only gets me to the middle as I come upon the corner. Frantically, I yank the brake handle and turn left. The car begins to rotate towards my turn. I throw it into second and get on the gas, wheel (no differential here!) wildly spinning as we slide sideways through the corner onto the new road, narrowly missing the 'Seasonal Road' sign. I stabilize the civic and look ahead at what appears to be a straightaway.

I made it through one more turn unscathed. My palms are sweating, my heart is racing and I'm back to scanning the limited view my headlights offer me. Baldi is slouched over the route map again, coolly prompting me.

"Reset. Right in 1.2 and you need to go faster."
____

The above is only about a twenty second excerpt from my six-hour, 160 mile road rally I entered this past Saturday night. I already gave you the background behind a TSD roadrally in my last post, so I'll recap the race here.

We started in Piffard, about 10 minutes outside of SUNY Geneseo, at some local bar. After filling out my entry forms and getting my car through a painless tech inspection ("Let's see- Roof? Check. Tires, with rubber? check. Hood, with no holes in it[for better or worse, see Subaru intercooler mount]- check) I looked around the parking lot to check out my competition. Yeah, I don't think I've seen so many STI's, EVO's and 2.5RS's in one parking lot at the same time. I felt immediately out of place and began to fear that I would end up stuck in the boonies somewhere without AWD. But I also spotted a Danger, a beater Neon and of all things, an Aveo. I summized that it must be at least possible to compete with my front wheel drive car. My mental goal was to beat the Aveo. Only slightly below my other goal of not wrecking the car in the next few hours. Remember those snow tires? They didn't fit, I'll be rollin' on all seasons.

A quick driver meeting and we were off the the OMP. Apparently, this is the part of the rally
were competitors drive AS FAST AS POSSIBLE. I mean, we left in the middle of the pack from the parking lot, and promptly got passed by every car behind us... I guess they were just savoring the paved roads.

We make it to the OMP just fine, and I get my first taste of what the night will entail. Hard-packed, snow-covered gravel road. Little did I know, this was one of the best roads I'd be traveling.

And, begin!
Baldi spits out speeds and distances and I hit the go pedal. The trickiest thing for me to master is resetting the odometer while turning, but I master it after a few corners. At this point it's nearly 5:30pm and quickly becoming dark. And starting to snow BIG snowflakes. While we were in the bar, I saw a weather report with a lake effect system coming up from the south west of the state, so I kind of knew snow would be inevitable. Whatever, I hail from the real upstate NY- snow can't hurt me.

Snow in the sky, snow on the roads, closed roads, a couple pants-filling experiences and a few checkpoints later we make it to the half-way break, sometime around 8pm. We end up at some gas station in Belmont, NY. Don't know where that is? Neither do I but I wasn't lost! There were more PA plates than NY plates in the parking lot. I get out to give the rally civic a quick once-over. It's still in one piece but now has custom racing graphics slathered on the side. All panels from the front quarter back are completely covered in a thick mixture of sand and slush, obscuring any white paint. The back end has 3 inches of snow packed onto it. The only color you can see is where the taillights have managed to melt the snow off the lens. I like the look but I'm too hungry to pay much more than a glance at it. Besides, I'm still on the clock and I need to get some food before the second half of the rally begins.

The second half of the race passed without anything special to note. I think the first half numbed my brain and any crazy incidents were just 'the norm' from then on. You know- sliding along a road with 8 inches of snow on it, bottomed out. A road which obviously had not been traveled all winter until the 17 cars spaced in front of me hit it. A road that is clearly marked as CLOSED. That kind of norm. We end at the bar again around 11pm.

So how did we finish? We secured 15th overall and 3rd place in the novice class. I'd say that's fairly good for my first rally attempt. Was it fun? Well, exhilarating may be a better word. I gave myself and Baldi a handful of scares along the route. If anything, I discovered the limits of the civic in the snow and those limits are pretty damn high. Will I do it again? Definitely. But I'm not doing it without snows mounted all around and a set of rally lights.

Oh, and I dominated that Aveo.

_ttk3

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Now playing: Dog Fashion Disco - 9 to 5 at the Morgue
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Rally Civic

2008-01-23T20:36:00.000-08:00

THE rally bug has bitten me. I guess it's a common species, attracted to bored engineers and especially harmful if said engineers congregate in small groups. [I have also heard reports that the humid warmth of machine shops also provide ample breeding conditions] So I guess it is no surprise that I find myself frantically trying to track down set of snow tires for this weekends road rally.

The Finger Lakes Region of the SCCA holds winter road rallys through these dreary months every two or three weeks from December to March. You would think that navigating a 200 mile secret-route through central NY wouldn't be too much fun. [Hell, why don't I just drive home for the weekend instead?] But, this isn't some day-dreamy trip down I90. The roads used are mostly limited use, unpaved back roads through the lake-effect prone snowbelt of western New York's southern tier. Did I mention it's at night? Oh yeah, that too.

The road rallys are Time-Speed-Distance (TSD) format. TSD is like a time trial, except that a driver doesn't try to get the lowest time, they try to match the goal time as close as possible, with every second that a car deviates from the goal counting as points. The car with the lowest points wins. Those ideal 'goals' are set by the rallymaster, and vary according to the speed class a driver is in (36,40,45 mph at this one). At this rally, I am a novice [n00b!1] and therefore in the 36 mph group. Those speeds don't sound like much, but those are average speeds, as soon as a driver misses a turn or gets lost...[you gotta make up the time somehow!]

But luckily, the driver isn't alone in this mess. Each car consists of a driver and a navigator. The two work as a team, with the driver frantically trying to stay on the road, watching for road signs and landmarks while the navigator reads off directions that resemble bad MS paint drawings and furiously calculates split-times, speeds and distances to make sure the car will arrive at the intended location on time.

And that's about all I know about format. There is all sorts of equipment that teams bring with them to more accurately determine their location such as rally computers and laptops with excel spreadsheets. But I don't have time for that [I build racecars instead]. I'll be relying on a trusty Ti-89 and a pencil. That's the cool thing about these rallys, you only need a car and some common safety equipment to compete. Most of the equipment I'm stealing from friends cars- towropes, DOT triangle, etc.

As far as getting the civic ready to drive, I just focused on items that will benefit me in the long run. I'm picking up a set of used snows on Friday and getting them mounted up. I rewired my fog lights, removing all safety items and relays, to get them to operate again. I also replaced my head light bulbs, with a high octane pair of Osram bulbs, straight off the boat from Germany. The picture is really only good for cosmetic comparison, but the performance is unbelievable! More info on these beasts over at honda-tech. I secured a co-driver, too. A fellow ME, so the math part shouldn't be a problem. He even has one road rally navigation under his belt, though that was in an AWD Legacy, the civic may prove to be a sub par vehicle for this....

Well, I guess that about sums it up. The rally starts at 5pm this Saturday and will last about 5 hours, if I don't get stuck [or broadside a stationary object]. I am hoping for snow, though only in that it's arrival will smoothen out the washboard roads around here. I promise to leave an update after the rally so if you don't hear from me, keep an eye out for a white civic stuck in a snowbank!

_ttk3

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Now playing: HORSE the band - The Red Tornado
via FoxyTunes

December

2008-01-06T18:11:00.000-08:00

THE month of December was a strange throwback to the days of my youth (...makes me seem old). The awkward calendar year had me selling Christmas trees on the farm for a couple of weekends, a chore that I had missed out on (gratefully) for the last few years due to school. It's kind of cool, until you have to attach a 15ft tree to a Yaris using only twine and a helping of luck. "Keep it under 80!" I tell the drivers, half grinning. They smile back and wave, wishing me a happy holidays. If only they knew that I never passed my knot test in boy scouts...

Even a healthy snow and lucrative temps in the –20s couldn’t keep me inside and I logged more than a few hours outside on the Bruin. If anything, the cold weather kept me outside more. I don’t know why, but I find it invigorating, the cold. So many hate it, but it’s great. The placid air piercing any uncovered area of skin- just makes me feel alive (and grateful for carhartts!). It's awesome because, as long as your dressed appropriately, you won't get cold. As opposed to summer, where you can be naked and die of heat exhaustion...

I also did something that I can’t recall. I read a book -for fun. I couldn’t quite recall the last time I read a book purely for enjoyment, I think it goes all the way back to elementary school; before teachers started assigning boring books that took up my precious free time and discouraged me from reading more (I never finished The Great Gatsby, don’t plan to either). Some of the last I read were London’s classics and I even got through Clancy’s Hunt for Red October and Red Storm Rising when I was in 4^th grade (and understood them, for the most part anyway). I knew what a HEAT round was capable of before my classmates had grasped long division (though I still don’t know my parts of speech). The novel that got me through this past month was Pullman’s epic His Dark Materials trilogy, which pretty much dominated my mind with it’s awesomeness for the last three weeks, and before you go on calling it a children’s book, it’s not. Don’t let a lamesauce cinematic rendition of the first book fool you, this book is capable of being interpreted on many different levels some of which fall way above the PG-13 movie rating. The novel was epic in every meaning of the word. It was a perfect escape for me from reality. And I’m not one of those weirdo fantasy people either. As Byron states it so exactly, “I hate all things fiction…There should always be some foundation of fact…”

But the best part of my break- there was absolutely no math involved. That’s important for someone like me who trudges through a sea equations everyday. Hell, my math is so advanced; I jump with joy when I get to use actual numbers in a problem. But all good things must come to an end, I guess. I finished the book, and now I’m left in a sort of depressed trance as I think back over the book and try to interpret it all, make it all relevant to my life, and hope one day I can write instead of crunching numbers daily.

So it is with a heavy sigh that I conclude my vacation (from both school and reality) this night, settling into bed with the eclectic sounds of late-night EQX quietly streaming from horribly low fidelity alarm clock speakers.

I promise something cool next time.

_ttk3

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Now playing: Harry Gregson-Williams - The Fear
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The Efficiency Paradox

2007-12-14T09:12:00.000-08:00

Seems like everyone these days is obsessed with efficiency. Planes, trains, computers even fast food chains are getting faster. Electronics use less electricity than ever. Car engines are smaller than ever. Chevy is even advertising a remarkable 23 MPG on some of their cars! I guess no one told them the Honda had 41 MPG with their 1973 CVCC...(fail)

Even commercial airline suppliers are jumping onto the efficiency bandwagon. Namely, the crue group labeled Airbus and the company who put the B in 747, Boeing. Granted the two companies are approaching the solution in two opposite and unequal ways. Airbus, responsible for the behemoth A380, created flying cattle carriers bursting with 853 passengers per flight. (All aboard the fail plane!) I guess the idea was to cut back on the number of planes in the air, and therefore cut back on pollution. It's a valiant attempt.

Boeing's philosophy mimics that of auto manufacturers; make the new model more efficient. Apparently, the new B-787's incorporate the best aerodynamic designs and technology ever applied to commercial airliners. The fuselage is composed of all carbon fiber composite, sending the cost of carbon everywhere soaring. It also uses redesigned engines that are quieter and more efficient than any other. (Who'd have thought those wavy-things around the nozzle would work so well?)

Anyway, I really only care about the engine efficiency (η). See, there's this weird paradox when you start analyzing engine performance. Aircraft engines move by creating a force called thrust, essentially some amount of fast moving air (m_a) coming out of the engine at some speed (U_e). In simplest terms, that air pushes against the air in the atmosphere. Obviously, you have to account for the velocity of the engine itself (U), as it is attached to the flying plane. Complicated math makes the force of thrust look like this:

τ = m_a (U_e - U)

Efficiency is just the amount of power you get out of the amount of energy you put in. So If you divide that thrust equation by the rate at which you're creating that energy, you get this:

η = (2·U) / (U_e + U)

Now here's where it gets awesome. In order to maximize your efficiency, you need to have the smallest value on the bottom of that ratio, that means that the exhaust speed must equal the planes flying speed. BUT, and look at that thrust equation, if that's true, the most efficient engine is one that is making no thrust. (It's turned off!!)

Anyway, if you learn anything from this post it should be that Chevy is dumb, everyone should buy a Honda and the most fuel efficient engine is never going to get off the ground.

_ttk3

Thrust Vectoring (or Pugachev's Cobra was so 1989)

2007-12-12T23:00:00.000-08:00

While wasting time on youtube, time better spent on homework, one discovers the strangest things. From teenagers who build waterslides off their parents’ house to cars that climb hundreds of feet of volcanic ash in seconds, the possibilities are limitless. A couple of months ago, I discovered a video of the Russian-designed Sukhoi-30 performing at an air show. I was blown away! The maneuvers that this thing is capable of are astonishing. It is even capable of flying backwards. For the record, those near-stall speed back flips are insanely hard to do perform according to flight dynamics, but that's another topic. I immediately started looking for information on the plane and found that most of its flight abilities were granted by the use of thrust vectoring control (TVC) nozzles.

Any engine that changes the direction of the jets’ exhaust from its normally axial flow can be considered thrust vectored. Thrust reversing, 2D and 3D nozzles are all examples of these specialized engines. Nozzles classified as '2D' can alter thrust in two directions, most commonly in the vertical plane, providing enhanced pitch control and in some cases, vertical landing and takeoff capabilities. '3D' nozzles provide the same vertical vectoring found in 2D but also offer vectoring in the horizontal plane. This enhances yaw control, advantageous during post-stall maneuvers. By vectoring the thrust leaving the engine, a moment is created on the aircraft that otherwise would not exist. Newton's second law takes over from there. This added force enables much faster changes in direction and maneuverability below stall speeds, not possible with conventional mechanical control surfaces.

Vectored thrust nozzles come in many shapes and sizes, but by far the most common form of thrust vectoring is thrust reversing (TR). Reversing nozzles are standard on almost every commercial jet liner produced. Commercial airliners use reverse thrust in addition to heavy-duty brakes, both mechanical and air spoilers, to reduce the length of required landing roll (distance). First installed on the Boeing 707 and the De Havilland Comet in the 1950s in order to operate from the commercial runways of the day. Other planes airlines were operating included the Douglas DC-3, which needed about 2600 feet of runway to land and the Lockheed Constellation, which needed about 3400 feet. While most thrust reversing is accomplished on the ground, some planes can apply TR in-flight, this enables rapid descents in altitude without over stressing the aircraft structures. NASA uses a highly modified Gulfstream to train space shuttle pilots in landing maneuvers. Because of the high angle of attack required to simulate a shuttle landing, the thrust reversers in the engine are enabled, limiting the airspeed that would ordinarily lead to failures of the airframe and controls (hmmmm, flutter and dive flaps, the topics are endless!).

Thrust reversing works by reversing the thrust of the jet engine. This includes the ‘hot’ exhaust gases or the ‘cold’ fan thrust. Some aircraft utilize reversers on both of the flows, enhancing the amount of thrust that actually changes direction, therefore stopping sooner. Old Boeing 747s and today’s C-17 Globemaster III (look the vents are open!!) turbofan transport are examples. Reversing engines come in three varieties with each accomplishing the direction change in their own way.

The first type uses internal ‘clamshell’ doors that close and evacuate the gases through built-in vents. The system is usually hydraulically activated. This method benefits from reduced drag from external components but suffers from the design in the same way. Since the doors are internal, maintenance time is longer. Pilots and crew cannot visually inspect the doors easily either, as all components are internal.

The second system uses external, hydraulic actuators that move buckets into the exhaust flow. Though increasing the amount of drag and engine has while in flight, the actuators are the easiest to service and make quick visual inspections of mechanisms possible. If a problem does develop; the entire system is essentially external to the engine, allowing a quick turnaround time from the hangar to the airfield. One can clearly see when this system is activated, as the huge buckets folding out behind an engine are evident.

The third system is the most common on today’s large, turbofan engines and usually only direct the ‘cold’ fan thrust. Once activated, a large inner blocker door is levered into position, at the same time outer vents in the engine nacelle are opening. The inner door directs the flow through the open vents in the cowling. This system is also apparent once activated, as the engine nacelle vents will be clearly visible. Since most of the thrust comes from the fan of a turbofan engine, a reversing device on the jet exhaust would not provide a great enough performance benefit for the weight it would add per engine. Here's an interesting fact- early B-747 models were equipped with both hot and cold reversers but most of the hot reversers were disabled, as they were high maintenance and seldom performed correctly. An exception would be Boeing’s C-17 military transport, which relies on both forms of vectoring due to the extreme takeoff and landing demands in a combat environment.

It may be surprising to know that the Federal Aviation Administration (FAA) does not allow the use of thrust reversing when calculating landing rolls for aircraft. Actually, the Administration states that thrust reversers should only be used to offset any other variables that could significantly increase required landing distances, such as weather conditions, aircraft loading or runway debris. Most people are shocked to learn that only the two inboard engines on Airbus’ giant transport, the A380, have reverse thrust capabilities.

By far the most exciting applications of thrust vectoring come from military aircraft. The extreme demands and operating conditions of aircraft in combat warrant the use of advanced technologies to gain any advantage over the enemy. Thrust reversing is nothing special compared to the technologies incorporated in some fighters today and actually is an outdated technology. Vectoring can be accomplished by mechanical means, such as changing the nozzle shape, or by more advanced, fluidic means.

The easiest, heaviest and simplest method is changing the angle of the motor. Using brute force and rotating the entire engine, the thrust can be directed in the appropriate direction. This method is employed on Bell’s V-22 Osprey tilt-rotor aircraft. The aircraft was developed as a vertical/short take off and landing (V/STOL) transport that could function like a helicopter but fly like a plane. This allows the Osprey to have all the advantages of helicopter maneuverability with the flight capabilities of fixed-wing aircraft.

In fighter aircraft, rotating the engine is not a feasible option. Fortunately, only the exhaust coming from the nozzle of the engine needs to be directed for any performance gain. Probably the more elementary method is that utilized by the Hawker AV-8 Harrier. This V/STOL attack aircraft was the first of its kind when it was developed in the late 1960s and has been updated through the years to increase its performance. One Rolls Royce turbofan engine powers the Harrier. The engine has two directional nozzles that provide 2D vectoring; one just behind the fan to divert cold flow and one at the rear of the engine to direct the jet exhaust. To provide rotational stability, small air puffers in the nose, wing tips and tail boom of the aircraft fire jets of air laterally. Flight tests are currently being performed on the newest V/STOL jet, Lockheed’s F-35 JSF. The whole rear nozzle on the jet deflects downward and, with the assistance of a fixed vertical fan behind the cockpit, allows vertical maneuvering.

Similarly, Lockheed’s F-22 Raptor utilizes a 2D systems, but only functions on the exhaust flow. The two Pratt & Whitney F119 turbofans have the ability to vertically vector 70,000 lbs of thrust ±20° from center. This provides the pilot with a beneficial moment about the lateral axis of the aircraft, enabling very quick pitch response and the limited ability to maneuver in post-stall conditions.

The ultimate in thrust vectoring performance comes from the implementation of 3D nozzles. These enhance yaw control in addition to aiding in pitch rotation. There are a few ways to do this. NASA’s X-31 and F-16 MATV projects used paddles to direct the exhaust. 3D TVC nozzles are also found on the Russian Sukhoi Su-30 and Mikoyan-Gurevich MiG-35 series of air-superiority fighters. The Su-30 uses a huge ball-joint connection between the nozzle and the engine. The nozzle rotates with the aid of hydraulic actuators. This system can be a bit bulky and a slimmer alternative is utilized on the MiG-35, F-15 ACTIVE and the F-16 MATV. This system overlaps flaps of the nozzle surface so it looks like the pedals of a flower. Internal hydraulic actuators push and pull certain ‘pedals’ to deform the nozzle. This system is the cleanest mechanical design, aerodynamically speaking, and also reduces the nozzles’ radar signature.

TVC can also be achieved by applying principles of fluid flow to the exhaust. Researchers have discovered that by introducing a jet of fluid into the exiting jet exhaust will cause the flow to change direction. By capitalizing on the properties of shockwaves, jets of air can be introduced into exhaust flow. As the jet enters the exhaust, an oblique shock wave is formed, deflecting exiting exhaust gas. Designers can also capitalize on the Coanda Effect in which a fluid tends to follow a curved surface. This effect is also known as boundary layer attachment. By introducing co-flowing and counter-flowing fluids into the exhaust along a coanda surface, the flow will change direction, as it wants to attach to the curved surfaces .

Fluid vectoring has some advantages over TVC by mechanical means. Although a mechanical thrust vectoring system is effective, it can be heavy, complex, difficult to integrate and aerodynamically inefficient. A fluidic thrust vectoring system has the advantage of being lightweight, simple, inexpensive and free from moving parts (fixed geometry), and can be potentially implemented with minimal aircraft observability penalty. (cough UAVs cough cough)

Super-maneuverable aircraft can’t just rely on advanced engine vectoring to push the envelopes of performance. Variable intakes that operate at extreme angles of attack must feed air to the high-performance engines in order for any TVC technology to be useful. Also, with today’s advances in fly-by-wire control systems, the computer must be able to calculate a situation based on the instantaneous characteristics of the aircraft. One method currently in development at NASA’s Dryden Research Center (please hire me! I don't care if I have to live in a desert!) is a method of determining airspeed without the use of a pitot-static tube. Dubbed Flush Air Data Systems, the device eliminates the need of an external measuring device and performs through high AOA maneuvers. By eliminating external pitot tubes, a plane can further reduce it’s radar signature, enhancing stealth properties. This system is currently being developed on NASA high AOA research platforms on a McDonnell Douglas F-18 fitted with TVC nozzles and Rockwell’s X-31 experimental plane.

TVC’s use in V/STOL aircraft is unparalleled and will no doubt continue to be a home for most of the technology. Though the technology is a huge advancement in aircraft maneuverability however, I do not believe it holds a place in manned fighter aircraft. Sure, its ability allows for phenomenal air show demonstrations and in extreme in-flight maneuverability, but the days of the close-combat dogfight are becoming history. I know, I know, that’s what McDonnell Douglas said when they designed the F-4 without a gun back in the 1960s but it’s true. With current avionics and weapon systems, targets are now acquired and fired upon before a bogey is even located visually. As of yet, unmanned aircraft have not engaged air-to-air targets but if they ever do make the leap, an unmanned aircraft will always outperform a manned one, due the limits of the human body. TVC does offer another layer of safety for those planes it is installed on. The technology could potentially allow a damaged plane to limp back to base using thrust control to assist control surfaces and its shocking ability to keep a plane in control, even during stall conditions could be useful if a plane ever entered into an ‘uncontrollable’ flat spin or other usually catastrophic situation.

Thrust vectoring is used to enhance the performance of a number of aircraft in service today. It has advanced greatly since its first applications on the commercial airliners of the jet age. TVC has allowed for aircraft that are able to land in record distances, planes that land like helicopters and epic air show demonstrations. Though future applications of TVC are still unknown to the public, there is no doubt that the advances will continue to push the envelope further than imagined.

_ttk3
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The Light Turns Green.

2007-11-15T20:42:00.000-08:00

The light turns green.

A faint ‘click’ is heard as the gas pedal depresses. There’s a low drone, a grumble, like that of a disgruntled animal whose cage has been jostled. Sixteen ports inject fuel into eight cavernous cylinders with a force of nearly seventy atmospheres. All while the piston approaches. Smaller and smaller, the volume decreases as the forged iron squishes the volatile concoction. Two – three – four thousand psi is surpassed until the stubborn fuel violently bursts. The flooded cylinder barely has time to burn before it is forced out.

Driven by 7.3 liters of controlled chaos, the waste exits, twisting and forcing its way toward an exit. The groan continues to build as the exhaust gases slam against the turbine. Slowly, the huge blades begin to spin, allowing the mounting hot gases to pass. Their trip continues, slowing for bends and joints in the restrictive pipe. An exit. Black smoke belches from the five-inch pipe, resembling a coal furnace catastrophe. The computer searches frantically for a stoich’ balance, as a cloud of unfiltered global warming forms outside.

The turbo machinery can be heard coming to life. A low whistle slowly builds. Higher and higher, the pitch increases until the mechanical snail is at a deafening scream. 3000 rotations per second slice and force air into the cylinder at some three bar of pressure. The computer manages to find the magic ratio and the particulates cease to emit, replaced instead by 700 degree exhaust fumes. ||

Yeah…I don’t think this is going to go anywhere. Mainly, because I don’t know how to explain a torque converter.

Damn it, now I still need a final project for my writing class.

Video

_ttk3

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Mike on Deck

2007-10-28T20:29:00.000-07:00

Hey Gang,
First off, I should thank Ted for letting me on-board with his little project here. I think it could be a good movement for both personal reasons (providing a place to focus on that "extra knowledge" I enjoy gaining) and a public reason; giving readers like you some material to enjoy with your morning coffee.
As Ted mentioned, the purpose of this blog is not to further depress myself like a 14 year old boy that wears tight girl's jeans, but rather a place to discuss more technical things; things like loads in race car chassis members, testing methods for drive train components, and other random enginerd speak. I may also throw in the random post about a recent movie viewing or maybe something stupid I saw while walking to class.

A little bit about myself:
I'm currently deep in my junior year at the University of Vermont studying Mechanical Engineering. I enjoy all things that go fast for no real reason and maybe some machines that actually serve a purpose. I have a strong belief that it is important to expand one's knowledge of engineering outside of the classroom and into either hands on applications or personal interests.

I have a few topics for discussion already worked out, so keep your eyes pealed for a revealing in the near future. While I would like to make this a regular event for posting an article, I don't think it would be as enjoyable if I knew I had to post every week, etc. However, I can see myself working on a topic through each school week and posting on a Friday; sort of as a way to vent and get away for the weekend.

Take care, go "lever it right" this week and come back soon.

Cheers,

Mike

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Engineers can't write...

2007-10-28T11:59:00.000-07:00

So I'm back on a blog. I canceled all my other ones on those other sites because I didn't want to be associated with an emo 8th grader. I don't plan on complaining about my life or trying to find my true love or getting the most e-friends [Tom was never my friend!], actually I'm not here to impress anyone.

I've started writing these again as a way to practice my writing skills and keep them in shape for when I need them [hopefully never]. I'll even try to use proper grammar [that's hard for engineers]. I'm an engineer by profession and a fun-loving teenager at heart and I'll combine those traits as best I can while explaining crazy concepts in engineering that most of you won't even care about.

So how about some topics? Well, anything with wheels, wings or and engine pretty much kicks ass so I guess I'll start there. I also enjoy ripping apart movies, poor machine designs and idiots who leave comments on youtube videos. Be on the lookout for posts along those lines. Hopefully you'll learn something and be able to post an intelligent comment on your next internet video or be able to work transonic flow dynamics into a conversation at your next cocktail party.

My first real installment will be thrust vectoring so here's a video to whet your pallet.
http://www.youtube.com/watch?v=U9fJDwgrYi8 [crazy beats yo!]

Enjoy,
_ttk3

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