Jump to content

LTE


rotor91
 Share

Recommended Posts

Greetings!

 

I ask, because I never thought it would happen to me! My buddy got into it in a 206 a few years ago, freaked him out quite a bit!

 

It happened about 2 weeks ago. I was having a photographer friend shoot something for me. The wind was coming at my 8 O'Clock(not that strong either), and I was trying to keep it at just above ETL. I did not hold it above ETL, and got just below, when all hell broke loose! I was in a R-22B II, at about 400 AGL. I was just starting to feed in some left pedal, I mean just, because I felt I was losing ETL. When WAMMO, we spun almost 800 degree's in about 2 seconds. I put in left pedal, but it really wanted to yaw right. I fought this for about 3 seconds, pulled a bit a pitch, which made things somewhat worse, lowered the collective, and we're still yawing left and right. It really wanted to spin right, I pushed it over, to get airspeed, and nothing happened. It was like flying those metal helicotpers outside a grocery store, no control input whatsoever. I know I was in LTE, and I needed to get airflow over the tailrotor, I again nosed it over abruptly, and we still had about 30-40 degree's right yaw, as it started to pick up airspeed. At just about 20 KTS forward airspeed, the nose swung right, and now airspeed is at 40 KTS. I can now remove my shorts from my crack, and check my pants! The whole thing lasted about 12-15 seconds, which seemed like 3 minutes.

 

I was hard on myself for introducing the LTE to ME. I thought(there's my mistake) the wind was fairly calm, but I might have had hit a gust of wind, because it felt calm. I'm glad I did not panic, and relied on my instincts, because I haven't experienced LTE before, I stayed calm, and made small control inputs(until I nosed it over the 2nd time).

 

I always learn something everytime I go fly, and boy did I learn something on that day...."ALWAYS know where the WIND IS".

 

R91

Link to comment
Share on other sites

Got into it twice on the same day. S300, Heavy, hot, high....light winds

 

First time was by accident, the second was deliberately.

 

I was doing a max power climb, whilst circling to stay inside a thermal. I let the airspeed bleed off to far (I was trying to stay inside a thermal to gain ascent rate), and sure enough the nose 'unanticipatedly' yaws right.

 

The recovery was text-book. Full left pedal, lower collective / reduce torque, gain airspeed. Maximum yaw was 180 degrees back into the wind. The student didn't even realise that it had happened. He just thought I had turned right!

 

So confident was I that I knew the contributing factors and the recovery of what had just happened, I recreated the conditions exactly the same again for his benefit. Sure enough at 20-30kts (or whatever it was) the tail swings again. We recovered and flew away. The student learnt alot from that.

 

So there we are - know the contributing factors and know the recovery.

 

Joker

 

(Before anyone slams me, we more than 2000' AGL.)

 

 

Rote91,

 

I would be interested to know what your aircraft AUWeight was, temperature and DA.

 

Thanks for sharing the story, and admitting to initially pulling the collective. Grave error, but I bet you don't do it again!

 

Joker

Edited by joker
Link to comment
Share on other sites

It happened to me twice, and when I asked about it a few years back everybody said it was highly unlikely in the robbie. Nick Lappos finally answered my question and then it made sense. If the wind is off your 10 - 11 o'clock position in the hover at high gross weight the main rotor tip vorticies can get into the tail rotor and disrupt the flow and thus LTE. I've since been told that it can be over come with left peddle but I probably didn't put in FULL left peddle and have since never experienced it again. Although now maybe with the onset of it I use Full left peddle and keep a closer eye on the wind direction.

Link to comment
Share on other sites

there are so many posts with words spelt incorrectly but this last one bothered me. In the course of whatever training you may have, how many times have you read the word "pedal". To not be able to commit this simple two vowel word simply baffles me. Makes you wonder how you could comprehend "Loss of Tail Rotor Effectiveness." Those are some hard ones! This is just an observation and in absolutely no way is this meant to cut anyone down, especially Low Level Lover, who is probably quite angry with me by now but I had to say something. "peddle", however, just took the prize for most butchered word I've come across on this forum. Again not trying to start a fight here, this more of a joke than anything and if spelling pedal wrong on purpose in your post was intentional, then hats off my man you've succeeded in making me look like a pompus preacher.

 

To the L.T.E now. Never experienced it but your posts have been informative.....thanks!!!!

 

"keep the peddle to the meddle"

-c

 

PS- If I can be of any help to you future readers on this thread, or just L.L.L

Peddle- To market, sell, get rid of

Edited by coanda
Link to comment
Share on other sites

I have encountered the on set of it several times. In on of my previous jobs I used to fly a 300 doing microwave relay for TV stations over marathons. We would fly with full fuel and be at a groundspeed that matched that of the runners. The onset is easy to recognize as you kept putting in the left PEDAL(!) anf the nose would keep going to the right. At that point in time it was a simple case of lowering the collective a touch, keeping the RPM high and flying out of it. We would fly at about 1500' AGL.

 

The hairiest one I had was in a 206 doing race support for a trophy truck race. I had a heavy fuel load and then the owner of the team turned up with some of his cronies - more than I had been told I'd been flying. Anyway long story short they wanted me to fly ahead of the truck around the course and point the nose of the helicopter in the direction of the course when I got to a 90 degree bend. I got to a corner, knowing that I was going to have a left crosswind. Pull into a hover, torque is going up, left pedal going in, it held for a second or two and then the nose snapped right. I dropped the collective, allowed the nose to drop and picked up what speed I could. I was about 200 feet AGL and lost altitude fast. No harm done - scared the passengers who got out asap, which suited me fine.

 

The key to avoiding it is to be situationally aware. Always know where the wind is coming from and know the performance capabilites of the aircraft. If the nose starts going to right and left pedal doesn't stop it, then immediately get some speed and reduce the power if you are able to.

Link to comment
Share on other sites

there are so many posts with words spelt incorrectly but this last one bothered me. In the course of whatever training you may have, how many times have you read the word "pedal". To not be able to commit this simple two vowel word simply baffles me. Makes you wonder how you could comprehend "Loss of Tail Rotor Effectiveness." Those are some hard ones! This is just an observation and in absolutely no way is this meant to cut anyone down, especially Low Level Lover, who is probably quite angry with me by now but I had to say something. "peddle", however, just took the prize for most butchered word I've come across on this forum. Again not trying to start a fight here, this more of a joke than anything and if spelling pedal wrong on purpose in your post was intentional, then hats off my man you've succeeded in making me look like a pompus preacher.

 

...

 

It's spelled 'pompous', not "pompus". And 'spelled' not "spelt". But I'm not cutting you down.... Oh, & the beginnings of paragraphs & sentences are usually capitalized. But I'm not cutting you down....

Edited by klas
Link to comment
Share on other sites

And I'll add this.

 

Main Entry: ped·al

Function: noun

Etymology: Middle French pedale, from Italian, from Latin pedalis, adjective

1 : a lever pressed by the foot in the playing of a musical instrument (as an organ or piano)

2 : a foot lever or treadle by which a part is activated in a mechanism

 

Oh, and lets get back on topic. That goes for me as well... :P

Edited by PhotoFlyer
Link to comment
Share on other sites

there are so many posts with words spelt incorrectly but this last one bothered me. In the course of whatever training you may have, how many times have you read the word "pedal". To not be able to commit this simple two vowel word simply baffles me. Makes you wonder how you could comprehend "Loss of Tail Rotor Effectiveness." Those are some hard ones! This is just an observation and in absolutely no way is this meant to cut anyone down, especially Low Level Lover, who is probably quite angry with me by now but I had to say something. "peddle", however, just took the prize for most butchered word I've come across on this forum. Again not trying to start a fight here, this more of a joke than anything and if spelling pedal wrong on purpose in your post was intentional, then hats off my man you've succeeded in making me look like a pompus preacher.

 

To the L.T.E now. Never experienced it but your posts have been informative.....thanks!!!!

 

"keep the peddle to the meddle"

-c

 

PS- If I can be of any help to you future readers on this thread, or just L.L.L

Peddle- To market, sell, get rid of

 

 

 

non sequitur [(non sek-wuh-tuhr)]

 

 

A thought that does not logically follow what has just been said: “We had been discussing plumbing, so her remark about astrology was a real non sequitur.” Non sequitur is Latin for “It does not follow.”

 

This is fun! Dictionary.com is great.

Link to comment
Share on other sites

*1 - there are so many posts with words spelt incorrectly but this last one bothered me. In the course of whatever training you may have, how many times have you read the word "pedal" *2. To not be able to commit this simple two vowel word simply baffles me. Makes you wonder how you could comprehend *4"Loss of Tail Rotor Effectiveness." Those are some hard ones! This is just an observation and in absolutely no way is this meant to cut anyone down, especially Low Level Lover, who is probably quite angry with me by now but I had to say something. *1 "peddle" *5, however, just took the prize for most butchered word I've come across on this forum. Again not trying to start a fight here, this more of a joke than anything and if spelling pedal wrong on purpose in your post was intentional, then hats off my man you've succeeded in making me look like a *3 pompus preacher.

 

To the L.T.E now. Never experienced it but your posts have been informative.....thanks!!!!

 

"keep the peddle to the meddle"

-c

 

PS- If I can be of any help to you future readers on this thread, or just L.L.L

Peddle- To market, sell, get rid of

 

Hmmm, just a thought.

 

1. Capitalise the begining of the sentences please.

2. Questions usually end with question marks.

3. Pompous, not pompus

4. Use of apostrophe is more appropriate here.

5. Not sure a comma is needed here.

6. etc..

7. etc...

 

Additionally, I believe that 'spelt' and 'spelled' are both correct.

 

In all seriousness, I actually hear what Coanda is saying. I think that the effort someone takes to 'proof-read' their work says alot about them. More people could do with doing that. Call me a traditionalist if you like, but that's what I think. While I let the odd typo through, I always re-read what I have written and usually end up editing it for ages before I let it go.

 

Still, it is fun to chuck it back in his face!!!! No hard feelings?!!

 

Joker

Edited by joker
Link to comment
Share on other sites

Got into it twice on the same day. S300, Heavy, hot, high....light winds

 

First time was by accident, the second was deliberately.

 

I was doing a max power climb, whilst circling to stay inside a thermal. I let the airspeed bleed off to far (I was trying to stay inside a thermal to gain ascent rate), and sure enough the nose 'unanticipatedly' yaws right.

 

The recovery was text-book. Full left pedal, lower collective / reduce torque, gain airspeed. Maximum yaw was 180 degrees back into the wind. The student didn't even realise that it had happened. He just thought I had turned right!

 

So confident was I that I knew the contributing factors and the recovery of what had just happened, I recreated the conditions exactly the same again for his benefit. Sure enough at 20-30kts (or whatever it was) the tail swings again. We recovered and flew away. The student learnt alot from that.

 

So there we are - know the contributing factors and know the recovery.

 

Joker

 

(Before anyone slams me, we more than 2000' AGL.)

Rote91,

 

I would be interested to know what your aircraft AUWeight was, temperature and DA.

 

Thanks for sharing the story, and admitting to initially pulling the collective. Grave error, but I bet you don't do it again!

 

Joker

 

Joker,

 

Temp was around 65, we were 2 guys at 200lb, and about 1/2 tank, DA was sea level! I've never been demonstrated the maneuver before. I pulled just a bit of collective, and went UH OH...that's not helping! :) Lowered it immediately, and eventually got out of the situation. I thought I might have gotten a beating for admitting this situation, but it turned out, that others have gotten into it too(un/intentionally as well!).

 

Also didn't know, this would become an grammar lesson!

 

Thanks all for sharing your stories too, glad I'm not alone in this! And yes Joker, I won't freak'n do that again! At least I know what to expect, if this were to happen again!

 

Rotor91

Link to comment
Share on other sites

Hey all,

yeah no hard feelings. I don't care. the main point of my last post.....there wasn't any. i was just drunk and having fun. As far as my spelling and grammar skills are concerned, lets just say after a half a bottle i think i held my own. ha ha. please don't cut me down anymore, it really hurts my feelings and i hate to cry, it hurts my i's. oops, eyes. Sorry to all who took it to heart, it was just an attempt at humor. failed obviously.

-man i could have sworn that i spell checked pompous and spelt...Microsoft Word is officially fired!

 

I apologize for disturbing this thread, I'll assume I'm forgiven if we all just forget this and get back to L.T.E.

Link to comment
Share on other sites

True Origins of "Pompatus"

The word, which can be heard in two Steve Miller songs, has long been a puzzle for music listeners, as it would seem to have no meaning. The characters in the film spend much of their time trying to decipher its sense, and wondering whether they were mis-hearing the lyrics: "Prophetess"? "Impetus"? "Profitless"? "Impotence"? "Pompous Ass"?

 

The true origins stem from an R&B song entitled "The Letter," written by the now deceased Vernon Green, leader of the Medallions. The song was Green's attempt to conjure up his dream woman.

 

To read more about pompatus' winding, spiraling history, see In Steve Miller's "The Joker," what is "the pompatus of love"?. As a result of Steve Miller's apparent "influence" by Green's song, the word weaved its way into pop culture.

 

Just for those not in the know

Edited by 67november
Link to comment
Share on other sites

I flew the OH-58C as an Army Aeroscout for about 2 1/2 years in some extreme conditions. Hot,high D.A.,

strong winds with high gust spreads, max gross. I have experienced loss of tail rotor authority many times

but would never let it develop into loss of tail rotor effectiveness. At tree top level, it simply cannot be allowed to happen. STAY AHEAD OF THE AIRCRAFT!!!

 

The gun pilots used to say "Scouts don't fly, they go for a spin." I made up my mind that I was NOT going to "go for a spin." KNOW YOUR LIMITATIONS!!!

 

 

 

That's not noise. That's the sound of freedom! Gen. Norman Swartzkoff

Link to comment
Share on other sites

Crickey COANDA, I never received such a reprimand for spelling in all my life. It was late when I wrote it and I had a blonde moment, and what the heck, I was drunk too. What are you going to say to the writer and editor of the article in "Rotor & Wing" (Dec. 2006 issue, page 13, blurb about the BA609 Civil Tilt-Rotor) I guess he / they were drunk too as they say, and I quote "they performed left and right PEDDLE turns". Now you have me paranoid about posting on the news groups,...................... Ah waht the hlel, for tshoe who hvae such a poblrem cnocrennig sllepnig teihr tmie wloud be betetr snept in a lietertray nwes gourp.

 

Ah, just having fun, now bak to L.T.E.

Link to comment
Share on other sites

I flew the OH-58C as an Army Aeroscout for about 2 1/2 years in some extreme conditions. Hot,high D.A.,

strong winds with high gust spreads, max gross. I have experienced loss of tail rotor authority many times

but would never let it develop into loss of tail rotor effectiveness. At tree top level, it simply cannot be allowed to happen. STAY AHEAD OF THE AIRCRAFT!!!

 

The gun pilots used to say "Scouts don't fly, they go for a spin." I made up my mind that I was NOT going to "go for a spin." KNOW YOUR LIMITATIONS!!!

That's not noise. That's the sound of freedom! Gen. Norman Swartzkoff

 

 

Please explain to a rookie, describe what it feels like to experience loss of TR authority, and once you recognize the condition what action do you take to stay ahead of it becoming full blown LTE? Your mention of tree top level addressed something I was thinking about when I read the previously posted recovery methods for LTE, most of the scenarios seemed to take place at forgiving altitudes. In at least two of these situations that have been described the pilots tried a few different recovery methods and succeeded through trial and error. Obviously we won't have that luxury at low altitudes. It's nice to learn about recovery but I would additionally like to know all about preventing it.

 

Also, thanks to the pilots who swallowed their pride and posted descriptions of their struggles to recover from LTE, you put your ego aside and helped some rookies learn the safe way.

 

Thanks, fly safe

Link to comment
Share on other sites

The second time it happened to me ( first at a 500 ft hover) I was at a 12 - 15 ft hover in a R 22, bad place to be but we all learn from our mistakes. Regardless, sitting there in the hover overlooking a building site everything is hunkydory when all of a sudden the heli yaws right quite aggressively and catches one off guard. I obviously put in left PEDAL but maybe not enough to stop the yaw. So I lowered the collective as much as my alt. would allow, gained forward speed and flew out of it. I don't think my passenger even knew what had happened and off we went. Lesson learned.

Kirt

 

Please explain to a rookie, describe what it feels like to experience loss of TR authority, and once you recognize the condition what action do you take to stay ahead of it becoming full blown LTE? Your mention of tree top level addressed something I was thinking about when I read the previously posted recovery methods for LTE, most of the scenarios seemed to take place at forgiving altitudes. In at least two of these situations that have been described the pilots tried a few different recovery methods and succeeded through trial and error. Obviously we won't have that luxury at low altitudes. It's nice to learn about recovery but I would additionally like to know all about preventing it.

 

Also, thanks to the pilots who swallowed their pride and posted descriptions of their struggles to recover from LTE, you put your ego aside and helped some rookies learn the safe way.

 

Thanks, fly safe

Link to comment
Share on other sites

Again I'm sorry LLL. It seems you didn't take my abuse too hard!! Thanks, the replies started making me nervous but glad to see you let my ignorance roll off. [i hope]

 

Anyway here is a L.T.E question:

What about flying with a NOTAR? Any wind/ attitude conditions to watch for? If its ever happened or even possible, have any of you experienced it? If so, is the recovery the same?

-c

Link to comment
Share on other sites

I've had it happen to me a few times. It always catches me off guard.

 

It had me baffled foe a while until yous guys shed some light on what was happening. When it happens, I throw in some left pedal. What happens next is confusing. It seems that the pedal input has no effect, because it happens so fast, that I throw in some right pedal. This exacerbates the problem, so full left pedal is applied. Meanwhile, Mike is freaking out and yelling "MAYDAY" on the radio. Everything gets back under control and it may, or may not happen again. It sucks.

 

That's all I have to say.

 

Later.

Link to comment
Share on other sites

The NOTAR can have the air flow around the boom separate in a right turn with a LARGE slip. When the air flow separates ease off the right pedal and the air flow reattaches. You will only get this flow separation at slow speeds and a very LARGE slip.

 

Craig

--Source (rec.aviation.rotorcraft circa 1995)

Let me wade in on this one, with some careful words about LTE.

 

The size and thrust of the tail rotor are the key determinate of the aircraft's propensity for LTE. LTE is not a pervasive single rotor helicopter problem, in fact, virtually all LTE occurrences involve only two types of helicopter, both Bell.

 

The term LTE describes the right yaw, but it is not a condition where the tail rotor gives up the ghost. Most occurrences involve pulling some power at the bottom of an approach, where the extra power absorbs the small amount of anti-torque available, and the main rotor torque takes the aircraft for a ride.

 

Cross winds can cause main rotor wash to enter the tail rotor and cause a loss of thrust of maybe 5% or so, enough that a marginal aircraft is kicked out of control. The key is to have enough extra tail rotor thrust to absorb this small loss, and also enough to allow some vertical maneuvering.

 

In smooth hands, LTE can be avoided, as long as the flight does not involve OGE maneuvering where the torque is high and the tail rotor is really pushed to its limits.

 

There was an FAA push to include LTE words in all single rotor helicopter flight manuals, but it was beaten down by all of those manufacturers who make helicopters with good tail rotor thrust margins. I assume the one manufacturer who experiences virtually all the LTE occurrences chose not to go it alone and create a

competative disadvantage.

 

I know of no H-60 or S-76 LTE events, not surprising when you consider their ability to sustain flight in 35 to 50 knot cross winds. This is also true of Apache and OH-58D. OH-58A/C, Bell 206 and Cobras are notorious for LTE, and the original OH-58D was rejected by the Army until the tail rotor was redesigned to eliminate LTE that occurred during bob-down maneuvers.

 

Nick Lappos

--Source (rec.aviation.rotorcraft circa 1995)

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
 Share

×
×
  • Create New...