wardialer
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Rotation Speed On Aircraft Carriers

Sun Jan 20, 2002 4:43 pm

What is the rotation speed for military jets taking off from aircraft carriers? (On a standard day in KIAS) We have seen them lifting off at a really short amount of time and I was just wondering about the rotation speed.
 
PPGMD
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RE: Rotation Speed On Aircraft Carriers

Mon Jan 21, 2002 2:52 am

I don't think they rotate (based on the footage that I have seen). Now that I think of it, unless they rotate in less than 5 feet its impossible to rotate while the their front wheel is in the sled.
At worst, you screw up and die.
 
flight152
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RE: Rotation Speed On Aircraft Carriers

Mon Jan 21, 2002 9:28 am

Rotation speed varies among different aircraft types.

Aircraft really don't rotate on an aircraft carrier though, they usually do it within the last few feet and finish after it has cleared the deck.

This should be posted in the military aviation forum.
 
aaron atp
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I Have To Ask

Thu Jan 24, 2002 8:05 am

how would you rotate if the nose is still connected to the catapult?

after the release, it's more about not hitting the water and not stalling than "rotating" as we think of it on land
 
PPGMD
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RE: Rotation Speed On Aircraft Carriers

Thu Jan 24, 2002 8:28 am

Well one thing that you will be taught as a CFI (and its pounded out of your head, it is a AC doc), that there is no such thing as a rotation speed on a GA airplanes, I think that would be true for fighters too. Not sure about that could be wrong.
At worst, you screw up and die.
 
Cicero
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Huh?

Thu Jan 24, 2002 10:46 am

PPGMD, perhaps you would like to expand on that last comment about rotation speeds on GA aircraft?

Which AC was that? apparently one I haven't read recently.
 
PPGMD
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RE: Rotation Speed On Aircraft Carriers

Thu Jan 24, 2002 1:37 pm

Let me dig it up, but I believe its 61-21 or 23 not sure off the top of my head, I read it while helping my friend study for his CFI test.
At worst, you screw up and die.
 
2912n
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RE: Rotation Speed On Aircraft Carriers

Thu Jan 24, 2002 1:57 pm

In the 300 foot run of the catapult the a/c reaches about 165 MPH. This takes about 2 seconds. Actual speed will depend on the a/c. They do not really rotate, they go from deck to flying in one movement. Depending on the load of the a/c some fly better than others right off the deck.
 
XFSUgimpLB41X
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Rotation Speed....

Thu Jan 24, 2002 2:56 pm

PPGMD: Huh?

Then why the heck is there a reccomended Vr (hmm.. rotation speed?) for every aircraft i have ever flown and ever will fly? It is in the POH... on the checklists...It is there.

Note that I did not get that pounded into my head when i was a CFI... nor did anybody else at my company or any other CFI that I know for that matter.
Chicks dig winglets.
 
aaron atp
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RE: Rotation Speed On Aircraft Carriers

Thu Jan 24, 2002 3:19 pm

VR is quite important I think... otherwise you would chance stalling or bounce the nosegear off!

WTF are they teaching these junior flyboys down at ERAU?

If it was 61-21 it makes sense, because that was the number for the basic helicopter handbook (does a helo need to rotate during a running takeoff?). 61-23 is the Pilots Handbook of Aeronautical Knowledge, and it certainly doesn't say that.

One more question I simply must ask... DID HE PASS HIS CFI TEST?

aaron
 
PerthGloryFan
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RE: Rotation Speed On Aircraft Carriers

Thu Jan 24, 2002 9:35 pm

Generally "rotate" means pull the stick/column back to your navel to get max pitch up so you can punch a hole in the sky with Vr the minimum/recommended speed for this to occur. This is necessary for roaring jetliners which have to be hauled off the ground. GA a/c on the other hand want to fly and you have to work hard to keep some of them on the ground when Vr is exceeded.

John Deakin's article at http://www.avweb.com/articles/pelperch/pelp0051.html about the checklist for the CAF's C-131 (CV340) makes an interesting point about "rotate" with respect to recip propliners.
quote
(3) The PF will, at that time (now passing about 90), lift the nose enough to extend the nose gear strut fully, and allow the airplane to fly off in that attitude. It should lift off just after passing V2.

(4) As the airplane passes refusal speed (V1), the PIC will take his hand off the throttles, as the clear and universal signal committing to the takeoff, even with an engine failure. (In other words, the PIC is required to keep his hand on the throttles until refusal speed, and then is required to move his hand OFF them after refusal speed.)

When the PF is positive the airplane will not contact the runway again, he will call "Gear Up," also giving the classic "Thumb Up" motion. The PNF must confirm the aircraft is well clear of the runway and not likely to settle back. One common technique is to observe an "up" indication on the vertical speed indicator, call "positive rate," and then call for or retract the gear. With some old airplanes, this may delay gear retraction a bit more than desired, as the initial climb rate is very low, and the VSI may lag for several seconds.

After the liftoff, there are three possible speed/climb options. THIS IS NOT A JET, and no major pitch up is EVER permissible! (Author's note: One of the most difficult habits to break in those who have flown only jets is the "Rotate" syndrome. Correct in jets, but BAD in recips! Recips are flown off the ground, not pulled off.)
unquote
Note the last paragraph in particular.

As for rotate speed of a carrier catapult - not applicable. The steam hits the cradle and you're off baby!
When the Australian Navy used to launch Grumman Trackers from HMAS Melbourne word has it that they closer to their Vne then any Vr!!

cheers
PGF

 
PPGMD
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RE: Rotation Speed On Aircraft Carriers

Fri Jan 25, 2002 1:30 am

I thin PGF pretty much covered it, that what I remember from the AC, I will have time to search for the AC and will post it over the weekend.

As far as ERAU, its not what they teach, its the FAA and thats what they teach. Yes he did pass it but it was off-campus, ERAU at least the procedures I see are really geared towards ATPs, the use of checklists for pre-flighting (horrible thing to do IMO, I've been a fan of the start here end here walk around).
At worst, you screw up and die.
 
Notar520AC
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RE: Rotation Speed On Aircraft Carriers

Fri Jan 25, 2002 10:04 am

Basically, the catapult throws you off the aircraft while you're engines are floored and once you're off the deck, then you rotate and climb out.
BMW - The Ultimate Driving Machine
 
aaron atp
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Joined: Sun Mar 19, 2000 1:17 pm

Ppgmd

Fri Jan 25, 2002 1:33 pm

Ummm... the way I read it, PGF's post did not support your statement...

His comments had more to do with how various wing loading and power loading differences between turbine/recip aircraft affect the rotation technique, certainly not that VR is unimportant in piston aircraft.

Most turbine aircraft have a high wing loading and lower power(thrust) loading ratio so it may require a heave on the yoke to break the surly bonds of the runway. The opposite holds true for most piston aircraft, low wing loading means you can 'fly it off' and high power loading means you can't 'punch a hole in the sky.'

Especially on the twins, if you begin rotation to soon, your VMCG is lowered due to the decreaseed nosewheel effectiveness, and you could be more likely to lose control in the event of an engine failure. This is why you don't practice soft-field takeoffs in multi-engine aircraft. Also, if you rotate at too low of an airspeed you are increasing drag and risking a tailstrike if below VMU , or if above it, a stall.

If you don't lift the nose soon enough, you might porpoise on the nose gear. VR

You can't just replace VR with an explanation of good pilot technique, it's apples and oranges. We know how it should be flown, but you still need a speed to reference.

"use of checklists for pre-flighting (horrible thing to do IMO"

One other note, you should read the article he linked to and what it said about checklist usage. If you keep that thinking, you aren't going to get very far in professional aviation.


aaron
 
XFSUgimpLB41X
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RE: Rotation Speed On Aircraft Carriers

Fri Jan 25, 2002 3:23 pm

As far as flow patterns go... especially since that is used alot on the preflight... a "do-then-check" philosophy should be adopted. Do the memorized flow pattern, then when it is completed go over the checklist to ensure all action items were hit.

There is nothing wrong with normal "read and do" checklists.

Checklists and flow patterns are what you live and die by. Slack off and start missing things and thats when things start going wrong.
Chicks dig winglets.
 
PPGMD
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RE: Rotation Speed On Aircraft Carriers

Sat Jan 26, 2002 3:20 am

I agree with checklists are important, but the aircraft walk around are more important things that one would only notice with a proper walk around, not just using a checklist, I have always believed in the start here (a wing strut, or I mostly use the spinner on an engine), then move all the way around the aircraft (pitot, landing lights, leading edge...) all the way around the point where you started.

I follow all checklists in the aircraft that I have flown in, but I always supplement it with a detailed walkaround, so I don't miss anything, like tow bar (I have more than once had to pull the tow bar off during the walk around).
At worst, you screw up and die.
 
aaron atp
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RE: Rotation Speed On Aircraft Carriers

Sat Jan 26, 2002 4:11 am

I predict that you will leave a set of gear pins in one day. Do you think your captain is going to hold your hand and show you what needs to be checked the first time you land a jet job? No. He'll probably do his own walk-around, but he isn't going to baby you. How would you know you were supposed to open the panel high on the tail that old lear and turn on the O2 in your preflight? Not to scorn you here, but your 152 isn't quite the complex aircraft that you will be flying in the future. You might not get much formal training before flying as an FO w/o a type rating on a 91/135 job. No flight instructor will lead you around the aircraft and show you each item to be checked. Why? It's in the checklist.

The checklist doesn't tell you how to do you walk-around, it is just a way to make sure you haven't forgotten anything during your walk-around. A good preflight checklist has a starting/finishing point on the aircraft, and each item progresses around the aircraft. Nearly every preflight checklist I've used is designed in that manner.

That having been said, I don't carry a checklist around the aircraft with me when I am doing my walkarounds, however I do check it when I get back upstairs; every time. The reality is, virtually no one carries a copy of the preflight checklist with them during their walk-around once they are comfortable with the aircraft. Most people I know do go through it after they've finished.

There is nothing wrong with doing it this way, after all, in the air you do the checklists AFTER you've completed most tasks...

If you fly with the FAA I would recommend you at least give that checklist a once-over.


aaron
 
PW4084
Posts: 287
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RE: Rotation Speed On Aircraft Carriers

Sat Jan 26, 2002 4:31 am



I agree that once you get comfortable with yr job you can do efficient walk-arounds without a checklist and then reference it when you finish. However, I feel your scenario re: a new-hire FO not being shown how to do a walk-around on a new type was unrealistic. If FO Snuffy is on his first flight w/ any 135 or 121 operator and doesn't know how to find the mysterious items on the exterior inspection checklist, something is wrong. I agree that the training w/ some of these jobs can be sparse but if his 'Training Department' (be it one guy who shows the new-hires the ropes or a whole facility of people) didn't show you what to look for on a walk-around they screwed up and so did FO Snuffy for not ensuring that he knew what to look for. Just another perspective... PW4084
 
chdmcmanus
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RE: Rotation Speed On Aircraft Carriers

Sat Jan 26, 2002 6:48 am

1. The previous statements about cat launches seem to be correct, basically the acft is airborne at the end of the deck, or the crew ejects. The necessary speed attained provides for a margin above stall speed based on weight and drag indexes.

2. PerthGloryFan is referring to unstick speed, the speed at which the aircraft wheels are allowed to leave the ground. Modern Vr for jets encompasses and ensures unstick speed is met. He is exactly correct about two vastly different techniques for liftoff between recips and jets.

Regards,
ChD
"Never trust a clean Crew Chief"
 
aaron atp
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RE: Rotation Speed On Aircraft Carriers

Sat Jan 26, 2002 3:03 pm

Perhaps you don't share my insight into the world of business aviation. If you are Part 91, training is usually crap. Some things you have to figure out for yourself, especially if the captain is the over-bearing type.

Not to bring it up again, but look at the people who were flying right seat 135 in the learjets over at SunJet... they were kiddies from the flight school across the street who didn't know wtf was going on...

my opinion
aaron
 
AAR90
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RE: Rotation Speed On Aircraft Carriers

Sun Jan 27, 2002 1:56 am

Speed is ZERO. You set stick/yoke position prior to launch. F/A-18 is only exception I know to this procedure. It has a "hands-off takeoff" option where the computers will rotate the aircraft to 10 degrees (I think) nose-up pitch after liftoff.
*NO CARRIER* -- A Naval Aviator's worst nightmare!

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