Strakes for Hueys?
 

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NAVAIR PATUXENT RIVER, MD - Press Release
Faced with increasing fatigue cracking in the tail booms of aging UH-1N Huey helicopters, H-1 program engineers here recently applied a commercially available aerodynamic device to help prolong the helicopter’s life as well as reduce pilot work load.

The device, a strake kit, developed by Boundary Layer Research, Inc of Everett Wash., consists primarily of an aerodynamically shaped strip of metal attached to left side of the Huey tail boom, according to Bob Moore, senior systems analyst with PMA-276.

“We were looking for something to fix our fatigue problems in the Huey tail booms in the short term,” Moore said. “We’ve got tail boom fixtures and other fixes in place, but we needed to reduce the stresses on the tail boom that cause the fatigue. We found this and saw it as something that would reduce the fatigue and help get us to our long-term fix for the tail boom.”

NASA, according to Moore, initially developed the technology. The technology was then bought by BLR and marketed to civilian single-rotor helicopter operators.

By manipulating boundary layer airflow produced by the helicopter’s main rotor as it passes over the tail boom, the strake kit improves the helicopter’s hover stability, climb and cruise characteristics, according to Dave George, spokesman for BLR.

Originally, the problem NASA discovered was that rotor wash passing over the tail boom of single rotor helicopters, like the Marine Corps’ UH-1N Huey, creates a fluctuating low pressure area along the advancing blade side of the tail boom. This results in a strong “suction” (or lift) force opposing the tail rotor thrust, thus requiring more power to the tail rotor to be effective.

With these increased opposing forces at work, affected helicopters experience increased component wear, greater fuel consumption, structural and performance degradation, increased pilot workload and a restricted flight envelope, according to BLR engineers.

And with older helicopters, the problems are even more manifest.
“We’ve been having consistent fatigue cracks,” Moore explained. “Between the two types of aircraft we support, the UH-1N for the Marines and the HH-1N for the Navy, we see a lot of hard flying. The UH-1N operates in the utility mode with lots of maneuvering, landings, etc. The HH-1N operates at higher altitudes, high winds and high gross weight.
“Both of them see a lot of stress,” he added. “And both of them are old.”
An aerodynamic process, called vortex shedding, is the culprit, according to BLR engineers.

The rotor downwash only flows smoothly down the sides of the tail boom for a short distance before curling into a vortex. The vortex gets bigger as it flows down until it is too big to “hide” under the tail boom and gets swept away. Meanwhile, the next vortex forms on the opposite side of the tail boom and the process repeats.

This alternating vortex shedding causes the tail boom to wag back and forth, and the associated vibration and oscillation causes increased fatigue and stress in both airframes and pilots trying to counteract the problem.

Enter the strakes.

The NASA research indicated that the strakes, when installed, would eliminate the problem by dramatically decreasing the vortexes and their effects by smoothing the airflow around the tail boom and eliminating the alternating sideways lift.

Moore, and his H-1 program colleagues who support fielded UH-1N’s and HH-1N’s, found out about the NASA research and the BLR strake kits and with the engineering support of Maj. Rick Bowen, the PMA-276 deputy program manager for UH/HH-1N Huey, they were soon testing a kit on a Huey assigned to Rotary Wing Test Squadron 21 here.

The kit, as applied, consisted of two strakes, each of which was formed from three 42-inch segments attached to the left side of the tail boom.

Rotary Wing’s Maj. Pat Lindauer evaluated the strake kit installation in 10 flight hours flown over the course of nine flights Feb. 5-14. His maneuvers included turns, approaches and departures, hovers, level, climbing and descending flight, and simulated engine failures.

“I was a little skeptical we would see all of the benefits [the BLR and NASA representatives] said we would see (lower power required to hover, lower tail boom loads, better pedal margins, more stable hover in yaw axis, etc.),” Lindauer said. “Because we did just a quick look, we were unable to measure some of the benefits and others were within the error of the standard aircraft instrumentation. However, the stab bar aircraft we did the test on was noticeably more stable in the yaw axis.”

The end result for the Fleet?

“I think the biggest benefits the fleet will see is improved flying qualities of the stab bar Hueys.”
Pilots at Marine Corps Air Station New River, NC have already agreed.
“The first time I picked up, I was over controlling the aircraft, but then it smoothed out,” reported Maj. James Judkins, maintenance officer for HML/A-167 at New River, and evaluator of the strake kit, after a recent flight in a strake-equipped UH-1N Huey. “It almost felt like I was flying in [a helicopter equipped with an automatic flight control system]. Hover performance seemed improved dramatically, and flying straight and level seemed to be easier than normal.
“I truly believe this modification is one the entire fleet should desire to get,” he added. “It’s an outstanding modification to the overall aircraft.”

With the initial indicators so good, the strake kits are on their way to the Fleet, according to Tom Boswell, program management support for the Huey deputy program manager.
“It follows that if you put this thing on the aircraft,” Boswell said, “and you need less tail rotor authority, it must mean you have less stress. We’re going to do a lot of qualitative testing to make absolutely sure we’re reducing fatigue and how much we’re reducing it by. In the meantime, we’ll have a formal Engineering Change Proposal approved within 180 days and then a Technical Directive will be released to the Fleet to authorize installation.”

Testing will also take place here to determine if the strakes will yield the same benefits when installed on an AH-1W SuperCobra.

Old hat I'm afraid, I've been flying them for over two years now on 205's, makes a hell of a difference.
Be interesting on 206's, I wonder when they will be on the market?

Interesting comment Rick.
I haven't heard such a strong positive statement on them before. Some have said "no change" and some have said a bit of a change. We have a few of the fleet outfitted, but the jury is still out......

What model of the 205 do you fly, what type of work, what altitudes, etc ??

Hi guys

I,m with Rick on the Strakes. Flown them lots on 204's and the difference is very positive. The aircraft is a lot more stable "out of wind" and the increase in performance is very noticable when moving from a strake machine to a non strake machine (we estimate 8-12% performance improvement).
I suspect that the unloading of the vertical stab will be a benefit structurally down the road but only time will prove me right or wrong on this one.

Ditto...the difference is significant!
So significant in fact that you need to be careful about hitting the RIGHT pedal stop in auto rotation with just a small breeze from the left....

...concur with the rest too! Esp the increased tail rotor authority in a heavy OGE hover.

**for what is worth the Brits have had them on their Sea kings for donkeys years!

It didn't really hit me at first, but the most noticable thing was that I was using at least 50% less pedal movement, especially on approach and hover. I haven't really noticed that much more lifting performance though I must admit.

407 driver: we use A Bell 206B's and Augusta-Bell B3's. No hot and high stuff but plenty of max AUW flying and lots of pleasure flights ( 40-50 lifts a day with 4 pax) in some very interesting confined little landing sites so I would be really interested in the strakes for the 206, especially given the weak tail rotor.

We have/had strakes on our UH-1H. The report from the Aircraft Research and Developement Unit (ARDU), aussie equivelent to Pax river, is not as positive as the comments above. It provided no tangible power improvement. It provided better pedal authority in some wind azimuths at HAUW. I don't believe the stability issues were that different. This is all from memory after attending briefs, reading the report (about 4-5 years ago) and ofcourse flying the aircraft.

On the other hand NASA and the Kiwis were very positive about the benifits. It just wasn't reflected in our testing. My own experience operating High and heavy on operations is that it makes ****** all difference.

Bell Huey operating costs
 

Does anyone here have an approximate figure on the direct operating costs for a Huey UH1H in restricted category?

Also how much fuel does it burn pr/hr? We don´t quite agree on it but I seem to remember having heard somewhere about 100 USG pr/hr!

Ain't the internet wonderful?
 

To: Aesir

Here are the hourly costs for the Huey (205):

Consumables
Fuel (95 GPH) @$1.50 US Gallon $142.00
Oil and lubricants (3% of fuel costs) 4.28
Maintenance and labor @ $35.00 162.40
Airframe maintenance parts only 320.00
Engine costs
Overhaul or exchange 145.54
Line maintenance 14.89
Total direct cost of operation 790.30
Normalized cost of operation 100%


:E

Lu:

Unfortunately the Huey costs are different from the 205, because they keep bringing out Service Bulletins to change expensive things and do expensive inspections.

Our Huey costs about $30,000* PER HOUR when you look at all the costs!!






* But it only flies 12 hours per year!! But still horribly expensive when you aren't allowed to carry anybody.

Huey v 205 I goofed
 

To: Ascend Charlie

The prices quoted in my post reflect the cost of operating the Huey not the 205. The prices were a cost comparison between the Huey and the Huey II upgrade. I can't verify the accuracy but they were quoted on the internet so that must mean that they are accurate.

:E

Restricted category UH-1H can only be the famous ZU 205 flying pax from the African aviation forum.

Good old South African aviation authorities saw fit to allow paying public access to old warbirds including a UH-1H in Cape Town.

Now then the law as written gives special dispensations and different rules about AD's etc and also allows other non factory mods to be done which are a considerable cost saver. You are also allowed to overhaul your own components.

Additionally there are other suppliers who have legal STC'd mods which peeve Bell off as they are approved but are a quarter of the price.

I believe a restriced 205 under these conditions can cost less than a 206!!!!

Have you tried Bells' website? I've looked at various manufacturers' sites; most of them make you aware of the existence of a model of machine and that's it. A look at Bell's site, on the other hand, will enable you to build one yourself from raw materials - the difference was that pronounced when it came to detail.

Thanks guy´s for the replies! I kinda have the feel that maybe a AS-350BII would be cheaper to operate for sling work than the UH-1H now! I don´t have enough work for a B-407 yet.

To "Hilico" I must say that in my experience NEVER ever trust anything that the manufacturer of a helicopter tell´s you!!! Although "if" I would trust any one´s word it would be the word of Bell helicopters.

Mostly the people in the field who operate these ships day to day are the one´s to ask and the one´s who know the actual cost of running the helicopter types.

I am a "BELL" man, but thats mainly because I know them and I know what I have, they break down and have their problems like any other helicopter. But I´ll try everything to get a Bell aircraft to do the job before I try anything else.

UH-IH checklist/PCM
 

Anyone know where I can download a copy of the Checklists and/or PCM. please?

"hatches, harness, heater, demister, electrics, volt/loadmeter, force trim off, caution panel out, fuel quantity pressure selection, Ts and Ps, audio, auto, full throttle, 66..."

There ya go!

Check your e-mail.

Jim

UH-1Y successfully completes special warfare testing
 

NAVAIR PATUXENT RIVER, MD

The Marine Corps’ newest utility helicopter, the UH-1Y, completed testing of its Special Warfare Kit at Marine Corps Base Quantico, last week.
The 10-day long event tested the helicopter’s ability to insert Marines into special warfare situations where landing the helicopter is not possible.

http://pao.navair.navy.mil/press_rel.../halo%20LR.jpg

Static line hung jumper evaluation, SPIE rig, rappelling, fast rope, and free-fall parachute operations from heights including 10,000 feet comprised the evaluations of the new helicopter’s abilities.

Correcting power deficiencies in the currently fielded Hueys is one of the primary reasons for the upgrade, as well as providing a platform for the Marines capable of inserting small combat teams into confined or rugged areas.

“We’ve restored the power margin lost in the N model,” Metzger added. “The Marines will be getting a good platform for helicopter rope suspension techniques.”

http://pao.navair.navy.mil/press_rel...ts/rappell.jpg

The improvements incorporated in the UH-1Y, including more powerful General Electric T-700 engines and an all-composite four-bladed rotor system, give the new Huey a vastly improved capability to conduct these special warfare missions over the currently fielded Huey, the UH-1N.

“Our special warfare missions play an essential role in the Marine Corps’ MAGTF concept and Seapower 21 Sea Strike core capabilities,” explained Maj. Brad Schieferdecker, H-1 Upgrades deputy program manager for Engineering and Manufacturing Development here. “The UH-1N’s restrictive power margin and weight restrictions have reduced our ability to do these missions in recent years. With the UH-1Y’s expanded performance, we’ll get back to being the Corps’ workhorse for these missions.”

The program recently passed a major milestone by gaining approval from the Defense Acquisition Board to begin low-rate initial production. Full-rate production of the 84-percent common AH-1Z and UH-1Y helicopters is scheduled to begin in 2006.

After remanufacture, the aircraft will feature the latest technology in rotor and drive train design, avionics, sensors and weapons. They also share approximately 84 percent of their parts, making them far more maintainable, supportable, survivable and deployable than today’s H-1 aircraft.

The H-1 Upgrades integrated test team here currently has achieved approximately 1,500 flight test hours with five aircraft (three AH-1Z and two UH-1Y test aircraft, of which all but one AH-1Z are production representative). The test aircraft have flown 220 knots, maneuvered from –0.4 to +3.5 g’s and been well above the 10,000-foot altitude mark.

By 2014, the Marine Corps will have procured 100 UH-1Y Hueys and 180 AH-1Z Super Cobras.

Caption to photo no. 1:

"On approaching Kemble, sensing that PF#1 was about to demonstrate his notoriously steep approach to runway 31, the senior passenger made an executive decision."

:E

Shy Torque:Very funny. But I don't think ten to twelve degrees is "notoriously" steep, especially for a guy (TOT) who claimed to have as much experience as he did. You'd think he would've known better, given the well-publicized noise-sensitive nature of Kemble. But what can you do...

Maybe if helicopter pilots made steeper approaches they'd be looking more downward and not outward and wouldn't hit wires with their Gazelles? Just a thought.

PF#1,

GOTCHA! :D

P.S. I always "chicken out" and use the other runway....:ok:

Thats a pretty picture for sure. A 412s, 412.....As they say when the last Blackhawk is flown to the Boneyard, the crew will go home in a Huey...

Tell us one thing you always do, and from which others might learn
 

A nearby thread speaks of an accident probably caused by a loose harness buckle snagging the cyclic. Where I was taught to fly it was a SOP that all belts should be buckled, whether or not someone was in the seat, and that all headsets not in use should be stowed. The reason, I was told, was the risk of loose objects snagging pedals, collective or, err...the cyclic. The chief pilot was ex-mil, and may well have had Gazelle experience for all I know.

The point is, I've always followed that piece of advice, believing it to be obviously worthwhile.

So, what do you always do that others should always do?

Left Collective Huey
 

Hi all
This may seems a ridiculous question, but I have to ask...I met this so called Vietnam vet (NZ around 55y) and during a chat, he mentioned that check flights done by the Check Capt, were done left hand seat (I agreed so far) but wait for it: No collective for the check capt....he flew the cyclic left hand and used the collective right handed???? Is this true or this chap read too many war books:confused:

Well as a young impressionable WO-G1 ( I reckon 21 years of age last year of 'Nam, I'd say his memory is cloudy and he was a
'REMF' with lots of mentors.......but then some of the hair-brained stories out of 'Nam are nearly as good as the other 'Nam....CheltenNam that is!!!!:D

First impression I'd have is that he'd need a 4 foot long right arm to reach across the centre console :rolleyes:

???
 

Was he big and hairy with LONG ARMS and did he answer you in Swahili?:hmm:
Might have been a Gorilla:}

Have you ever tried to ride a bicycle with your arms crossed over? It doesn't work, as your learned responses are too ingrained.

I doubt that there would be too many people who could fly a cyclic with their left hand and work the collective with their right, especially in the rapid-response world of a check ride. I have tried to hover a Robbie from the left seat, using my cyclic and Bloggs' collective, but it was hopeless. Anybody else able to pull off an auto that way?:confused:

Hasn't happened to me, but a Malaysian friend of mine related a story where he was instructing in an Alouette (from the left seat naturally), and during the flare of an autorotation he was demonstrating, the collective disconnected. He switched hands to left hand on cyclic, right hand on student's collective and did a good landing.
So it can be done, but perhaps not as a matter of course.

Not being Gods Gift to Aviation but having flown with a couple, I can tell you its not easy but doable. I have flown with one IP who used to assist folks on the collective during autos and one can reach over in a UH-1 and do it.
One guy in particular (Steve Isle) in Sacramento is so comfortable in that machine, he can put it anywhere you want him too. Its going to ba a loss to the Instructor world when he retires.

Can't answer for the Kiwis, but we Yanks had full duals in ALL or our Hueys. I've never seen a modern aircraft with partial duals, althouogh my understanding is that some very early helo had'em.

All my checkrides were flown right seat, but some ACs (aircraft commanders) prefered the left, better vis as there's less panel before you, and likely took their rides in that seat.

I have met "Viet Nam Vets" who'd tell you stories, sometimes actual lies. Not me, of course.

FWIW, early helicopters (Sikorsky R4 springs to mind) had only one collective, and the left seat pilot flew left handed, with his right hand on the common collective. This is often quoted as the "reason" that helicopters are (generally) flown command from the right seat, since this is the "natural" seat for a right handed person.

Since the R4 was so narrow that two people have trouble sitting side by side, the manipulation of the collective must have been a cosy arrangement.....;)

The Sycamore had a shared collective in the middle which made it fun for the check pilot if he wanted to grab it in a hurry.:O

Even more fun in the Sycamore (I've been told - even Teehead not that old!) was the manual throttle from the LHS; not only used with right hand, but rotated forward - it was the cross-piece on a Tee-shaped collective located centrally.

Very disorientating flying "wrong-handed"; for many years CFS(H) [who train all UK mil helo instructors] include a "wrong-hands hover" demo for student instructors ... amongst other reasons, so they could remember how hard hovering is the first time you try!

A QHI at Shawbury once took control from his student in a Gazelle in a confined area to debrief him - for some reason he took the cyclic in his left hand and the RHS pilots collective in his right. They promptly speared in (survived with few injuries) not surprisingly. As a result of this crash we had to put student QHIs in the LHS of the Gazelle and let them try to hover it in this fashion - just to prove what a stupid idea it was. With practise it can be achieved but more often an brief period of relative stability is followed by a rapidly worsening situation as the pilot tries to use his left hand (now on the cyclic) to correct the height errors and his right hand to selct the hover attitude.

Hovering would be a challenge, but switching hands during forward (stable) flight isn't so bad. Last time I was up with a CFI, I started practicing the switch. In the Robbie, it will be a convenient skill to have when instructing from the LHS and you need to reach over to switch freqs with your right hand. I wouldn't do it in a hover or emergency (hopefully).

Ahhh, the joys of flying the Sycamore.
The collective was actually "L" shaped, with the throttle on the end facing right. Early Syc. were flown from the left and had a conventional left collective, but I can`t recall that later models had one, only the one in the middle.The throttle/ collective cam arrangement/linkage was pretty variable , so on raising the lever, if the RRPM weren`t right you had to wind on/off throttle as the case may be. Taught you to have a well-tuned set of ears, so you could concentrate outside to see where your next problem was.
It also had: Wooden matched blades
Manual controls, and trimmers( big wheels like f/w!)
An electric pump for the Cof G compensating system( as pax were carried in the cabin, the c of g went fwd, so you pumped fluid from the front tank to the aft one in the tail boom-- and vice-versa as pax were deplaned) Victor Borge wrote about a similar system ! and it was easy to get it all wrong.

As the hover trim control positions and forces were different from fwd flight, you had to set the manual trimmers as you were doing the approach, and remembering to adjust the Cof G compensator as well, and of course vice-versa.!!!!

If you got the touchdown ok, as you lowered the lever, you had to trickle fwd, as the tyres would roll off the rims--- at this point, as there was a change in RRPM, YOU WOULD INVARIABLY BURST INTO GROUND RESONANCE, especially on concrete /tarmac !!
So, it was either, full power and get airborne, or if the RRPM were well down, then ride it out.

On the other hand, it was the only helo that I`ve done max- rate turns in-- full power and pull as hard as you dared....

Oh yes, nearly forgot; you could als do a "jump t/o", by overspeeding the RRPM, then pulling pitch and hoping you got to TL speed before the RRPM had decayed too much , or you touched down at high speed and then got ground resonance, and............%$&(*???

So, anyone think they`d like that as a basic trainer??
Great aircraft , sorted the boys from the men... on our basic course , it was the "old farts", ex -fighter pilots who had all the problems; us lads just didn`t know any better....... :ok:

Huey again
 

In an interesting parallel to the case in South Africa, a similar battle is brewing in the US with the FAA.

US operator details objections to FAA.



Waterfront helicopter takes flak in court

February 13 2004 at 10:19AM

By Karyn Maughan - Cape Argus

It survived the Vietnam war, but one V&A Waterfront-based Huey helicopter might find its rotors clipped following an urgent application in the Cape High Court on Thursday.

The Waterfront sought an order stopping Helicopter and Marine Services and the Huey Extreme Club from flying an allegedly "unairworthy" ex-military helicopter from its helipad, as "each time the Huey flies it's in contravention of the grounding order", the popular tourist destination was "at serious risk".

The helicopter was grounded by the South African Civil Aviation Authority (CAA) on January 7, but continued to fly until January 17, when it made a forced landing in the Cape Town flying area and allegedly had to be towed to its hangar for repairs. It was used for flights again - in alleged contravention of the grounding order - on January 29.

It emerged in court on Thursday that the Huey, registered as ZU-CVC-B205, was constructed from four helicopters which had served in the United States, Israeli and Ethiopian air forces and which had been sold to a South African businessman.

It was used for flights again

"We hope that this helicopter does not suffer, like many other Vietnam vets, from post-traumatic stress syndrome or feel the effects of a few whiffs of Agent Orange," said Cedric Puckrin, advocate for the CAA.

Although cited as a respondent in the case, the CAA says it supports the Waterfront's efforts to enforce the grounding of the Huey.

The authority is also currently engaged in a safety audit of the helicopter and is sourcing information from Taiwan and Italy.

Puckrin - assisted by junior counsel Gordon Aber and Guy Elliott - pointed out that military aircraft were held to less rigid safety standards than their commercial counterparts.

Puckrin also referred to a letter written by Bell, in which the helicopter's manufacturer stated many changes had been made to its military-use helicopters without its knowledge or approval. Bell said it was therefore unable to take responsibility for their continuing airworthiness.

The CAA says it supports the Waterfront's efforts

In response to charges that it had failed to keep proper and appropriate records of its helicopter's parts, the Huey Extreme Club - represented by Peter Hodes - claims it is not a commercial venture and therefore has no obligation to comply with commercial flying regulations.

It described the helicopter's condition as "exemplary" and said it had "an impeccable safety record".

It also denied that it flew over the Waterfront.

In an affidavit before the court, the Club said its "sole source of income" came from its "membership fees" - adding that the grounding of its helicopter would remove the incentive for "day members" to join. Such "day members", it emerged, would pay a R750 "joining fee" and thereafter enjoy a "free" introductory flight.

"This is what one would describe as a 'foefie'," said Puckrin - describing the Club's self-proclaimed club status as a "stratagem" intended to prevent it from complying with commercial flight safety regulations.

The case before Mr Justice Jock Comrie continues.

US operator objections.

I am so glad the CAA worries about a veteran that served in combat and in all liklihood sniffed Agent Orange and suffers from Post Traumatic Stress Disorder (PTSD). That certainly is heart warming of the CAA...shame the very veteran's that flew Huey's into the same combat did not get the same concern from the American Veteran's Administration. Just like the Gulf War veteran's did not get any concern when the Gulf War Syndrome struck down so many and that problem also got ignored.

The truth of the matter is simple. Even this old Huey, just as human veterans, with tender loving care, even the Veteran with PTSD, can live out a normal productive life and those that have Agent Orange complications all have diseases that are slow acting and easily diagnosed. The one exception being birth defects.

We do not see any Baby Huey's out there....except in positions of officaldom that make statements such as the CAA gentleman being quoted. Of course, this issue requires one to be a Veteran and probably an American to understand what a Baby Huey is?;)


But really...why was it perfectly legal ...then and still is...for me to fly my UH-1H day and night...fair weather and foul...with a full load of soldiers....into and out of LZ's under hostile fire...but now the very same aircraft design is unsafe for carrying passengers for a Jolly around an airport or fairgrounds?

There is a much bigger issue here....are our soldiers getting the short end of the stick or is the regulatory system out of whack? Just why is Bell Helicopters so worried about the "Liability" issue? :(

I thought that the objection by Bell was due to the damage to it's civillian sales figures that the military surplus machines pose.........And while we've got 'em in the spotlight, how about some of that legendary Bell product support for the Bell 47 operators of the world, instead of trying to price them into 206s:yuk: