MD600
Joined: Jan 2001
Posts: 739
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From: Dallas, TX USA
Nick, when you say.... .. .There are by far more parts to go wrong,. .. ....compared to NOTARs, does that parts count include the extra drive shafts, couplers, bearings, and gear boxes of the conventional tailrotor? I do agree with you however that it's really a matter of choice.. .. .Just curious, what is the demonstrated reliablity (service in the field) of NOTAR's compared to conventional tailrotors, and how is this affecting customer satisfaction with the MD600N (or the MD520N or the Explorer for that matter)?
Thread Starter
Joined: Apr 2001
Posts: 113
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From: SoCal
Nick, the SAS system is not a required flight item. Last night I spent four hours in 30 kt winds flying a 520N without one. It wouldn't have made much difference though. <img border="0" title="" alt="[Frown]" src="frown.gif" /> . .. .Flight Safety, our 520N's spend as much or more in maint for tail related items (liners. blades) then our D/E models. The 600's are just hangar queens. With the aft transmission for the fan, hub, 13 blades on the fan, pitch control, thruster control, they did not reduce the number of parts, just the shaft lengths.. .. .And look at what Border Patrol just did. Bought A-Stars instead of the 600N.
Joined: May 2001
Posts: 1,691
Likes: 3
From: Escrick York england
nick sorry you are wrong. .the 600 does not have a mandatory stabilisation system in fact it does not have one at all the ysas system that is in the 520 has just been certified now for the 600 but there is none available from mdhi. .. .also you wrote let the customer decide . .. .i did and i am happy with it the 600 is the sports car of helicopters [only upset that mdhi have not got any ysas yet..]. . . . <small>[ 15 March 2002, 09:00: Message edited by: md 600 driver ]</small>
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Well I am off base about the mandatory sas for the 600, sorry!. .. .The 520 can swap ends if there is no sas, the 30 knot reagon is not the bad one, high speed is the problem. Chan Morse swaped ends in test, which lead to the sas requirement, if I remember his conversation correctly.. .. .If you look at all the critical parts, the Notar has a bunch more than a tail rotor. How many blades does that screaming fan have, and how many blade grips and bearings? The tail shafting is longer on a tail rotor, granted, with two or so bearing supports. I havn't seen a cutaway of the transmission to count the fan drive section, and compare it to a tail rotor gearbox. The tail rotating can has bearings and a control system, and is there a rudder? All that stuff is important and carries a parts count. In total, I'll bet there are twice the critical parts in a Notar.. .. .The one factor you all didn't challenge is the loss of payload. That small fan eats power, the tail thruster eats power. When we designed Comanche, we found that the power loss of the proposed, not built) Notar was its biggest detractor.. .. .The noise and protected tail are big advantages, so there is not one "right" answer, ever.. .Your collective enthusiasm says plenty, because you are the deciders, in the end!
Joined: Feb 2002
Posts: 14
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From: Canada
HeliMark, you're right, in case of complete anti-thrust failure, there is no difference if you have a rotor system or not. But I can assure you that in case of pedal stock, the coenda effect makes it easier and safer to land. . .As I told you all before, if I was flying from helipads to helipads (heliports to heliports)I would prefer a conventionnal tail rotor. But, in dense forest confined aeras or on long line ops, I'd go with the Notar. . . If your tail boom tip goes one feet under water at 100% rpm, would you be able to take off without any damage? That is what I mean bye safety during ops.
Thread Starter
Joined: Apr 2001
Posts: 113
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From: SoCal
ylhelico, I do not agree with you as far as having a stuck pedal. The amount of coanda effect is also affected by the air coming out the slots from the fan. The pitch of the fan is directly connected to the pedals. Lots of air means lots of anti-torque you do not need. And add the thruster equation to that also.. .. .What is worse, is the manual says that if you have a fixed thruster setting "Use powered landing, otherwise it is unlikely that an autorotation can be accomplished.". .. .I am not sure if you have practiced something like a stuck right pedal (say pushed by the instructor 1 1/2") to touchdown. The factory pilot says in that case, touchdown needs to be in the area of 60 kts or greater. <img border="0" title="" alt="[Eek!]" src="eek.gif" /> There is another method of a manuver simular to a power-on auto, making the nose swivel to the left on your decent and touching down at about 10 kts as the nose is swinging right. . .. .There is no question about the safety of the NOTAR as far as the tailboom hitting something verses a tailrotor.. .. .Part of my job is searching for lost hikers in the mountians. I do a lot of confined ops along with one-skid/toe operations. The difference in control between the two is vast. The NOTAR is like a wallowing pig compared to a tailrotor. And we could add the lack of power they have. . .. .Nick, the best we have been able to get the MD people to admit to is anywhere up to 210 hp to run the tail when asking for a bunch of anti-torque. I believe that the most the "E" will grab is around 65 hp. And even though the NOTAR burns around 6-8 gallons more an hour, inorder to carry the same that a 500E will, we have to carry less fuel.
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Helimark,. .The fan power varies just like the power to a tail rotor, so there is no one number. Also, the coanda slots are quite efficient, so when the downwash is perfectly aligned with the tailcone, the Notar is not toobad on power. But if the wind is slightly from the tail, the coanda is of almost no use. The original Notar experiments found no yaw control when the wind was 6 knots from the tail, so the can was added to create a tip jet.. .. .One funny thing about power losses is that hover charts in the flight manual are determined in still air, when the main rotor power needs are highest, but when the coanda is most efficient. With any wind or maneuvering, the tip jet becomes the anti-torque device to a fair degree, so the engine power needed goes up, unlike a conventional helo.. .. .For most helos, 1 horsepower lifts about 6 pounds in a hover, so if the Notar eats 25 horsepower more than a tail rotor, that costs 150 pounds of payload. A common tail rotor uses about 5 or 6% of the main rotor power, so a 400 HP helo uses 20 to 24 Horsepower in its tail rotor in a steady hover. If a Notar uses twice that (I think that is a fair estimate), it can lose about 1 passenger as compared to an otherwise identical tail rotor equipped helo.. .. .The protection of a notar is legendary when compared to a tail rotor. If the can in back is bent or jammed by a ground contact, you can get a stuck pedal, but the strike that jams the can would certainly toss a tail rotor into the next county.
Thread Starter
Joined: Apr 2001
Posts: 113
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From: SoCal
Just to update.
The L.A. County Sheriff has grounded all three of their 600's due to cracked bushings on all of the vertical stabilizers (there is four on each bird). What is worse is that the factory has known about this situation for some time, and failed to notify any operators.
The L.A. County Sheriff has grounded all three of their 600's due to cracked bushings on all of the vertical stabilizers (there is four on each bird). What is worse is that the factory has known about this situation for some time, and failed to notify any operators.
Joined: Oct 1999
Posts: 1,444
Likes: 21
From: Beyond the black stump!
Sounds about par for the course!
When I was involved with this product, I used to go to the operator meetings (can't remember what they called them now).
After I had been to a couple, I realised that it was going nowhere - the same issues were discussed time and time again, without any commitment to resolve the problem.
Then I became really alarmed when they brought out an old timer, who told us that all these problems had been around for years, and that fix #15A still hadn't solved the issue, but fix #17B was in the works!
Virtually every problem was along the same lines.
The MRB problems were absolutely horrific, with virtually every blade being returned to the factory numerous times for warranty work.
I still think the most amusing occurence there was a very contentious dispute over MGB gear scuffing, which resulted in gear rejection at every overhaul. There were some discussions about polishing contact surfaces, but they would have none of that. One of the larger MD Helicopter operators, then informed everyone that he had inadvertently discoverd a legitimate solution for the problem. Prior to every MGB reaching 1000 hours TSO or TSR (warranty limit) he would reject the box for "internal noise". This resulted in the box being torn down for inspection, nothing was ever found, except the gears would be noted to be scuffed beyond limits and replaced free of charge!
MDHS had some very good and very conscientious people working for them. Some really took the comapny's inability to provide acceptable service very personally - they hated it and worked so hard to make it better. It just never seemed to get there though - lack of corporate commitment to the product line.
The new owners have made a sincere attempt to improve the product, service and commitment. The biggest problem is overcoming the years of inattention these products received.
When I was involved with this product, I used to go to the operator meetings (can't remember what they called them now).
After I had been to a couple, I realised that it was going nowhere - the same issues were discussed time and time again, without any commitment to resolve the problem.
Then I became really alarmed when they brought out an old timer, who told us that all these problems had been around for years, and that fix #15A still hadn't solved the issue, but fix #17B was in the works!
Virtually every problem was along the same lines.
The MRB problems were absolutely horrific, with virtually every blade being returned to the factory numerous times for warranty work.
I still think the most amusing occurence there was a very contentious dispute over MGB gear scuffing, which resulted in gear rejection at every overhaul. There were some discussions about polishing contact surfaces, but they would have none of that. One of the larger MD Helicopter operators, then informed everyone that he had inadvertently discoverd a legitimate solution for the problem. Prior to every MGB reaching 1000 hours TSO or TSR (warranty limit) he would reject the box for "internal noise". This resulted in the box being torn down for inspection, nothing was ever found, except the gears would be noted to be scuffed beyond limits and replaced free of charge!
MDHS had some very good and very conscientious people working for them. Some really took the comapny's inability to provide acceptable service very personally - they hated it and worked so hard to make it better. It just never seemed to get there though - lack of corporate commitment to the product line.
The new owners have made a sincere attempt to improve the product, service and commitment. The biggest problem is overcoming the years of inattention these products received.
Joined: Jan 2001
Posts: 94
Likes: 1
From: Ottawa, Canada
Just to make a comment on something said on the last page by Mr. Helico....
- If you're buying a helicopter to stick its tail in the trees or one foot under water, and then fly away afterwards, maybe you should be driving a pick-up truck instead.
- After 15 years of looking down a longline in everything from 500Ds to Sikorsky 61s, I'm missing the part about how not having a tail rotor could have helped me.
- If you're buying a helicopter to stick its tail in the trees or one foot under water, and then fly away afterwards, maybe you should be driving a pick-up truck instead.
- After 15 years of looking down a longline in everything from 500Ds to Sikorsky 61s, I'm missing the part about how not having a tail rotor could have helped me.
Thread Starter
Joined: Apr 2001
Posts: 113
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From: SoCal
Cyclic Hotline, from what I have seen for the last several years, I disagree on the new company trying to correct the support issue. Well some of it at least.
Yes, when MD took over, the president, vice-president and all the support people came to us and gave us the new better support speech. Also to hear our complaints. Nothing has changed, really. And this tail problem is being paid by the customer. This is the third time that the operators are finding cracking problems that they (MD) have known about prior. Now that is real confidence.
Yes, when MD took over, the president, vice-president and all the support people came to us and gave us the new better support speech. Also to hear our complaints. Nothing has changed, really. And this tail problem is being paid by the customer. This is the third time that the operators are finding cracking problems that they (MD) have known about prior. Now that is real confidence.
Joined: Oct 1999
Posts: 1,444
Likes: 21
From: Beyond the black stump!
Whoops, let me clarify that.
Helimark, let me clarify my statement. Believe me, in no way would I ever endorse any MD product (as stated here and on other forums!)
I stated that the new management had attempted to improve everything, but if you look to my first comment - this current issue is par for the course!
There is a never ending litany of unresolved (or half-assed solutions) to the MD fleet (my experience is limited to the 500).
They are simply the most unreliable, expensive, maintenance intensive, overly complicated, poorly supported product I have ever had the misfortune to operate. The provision of PMA parts has gone some way to reducing costs and remedying the parts supply and availability issues. I would not operate one if you gave it to me for free.
As I once commented on here : My MD500's are (were) the quietest helicopters in the world - because they are always broken down!
I stated that the new management had attempted to improve everything, but if you look to my first comment - this current issue is par for the course!
There is a never ending litany of unresolved (or half-assed solutions) to the MD fleet (my experience is limited to the 500).
They are simply the most unreliable, expensive, maintenance intensive, overly complicated, poorly supported product I have ever had the misfortune to operate. The provision of PMA parts has gone some way to reducing costs and remedying the parts supply and availability issues. I would not operate one if you gave it to me for free.
As I once commented on here : My MD500's are (were) the quietest helicopters in the world - because they are always broken down!
Just Dropped In
Joined: May 2001
Posts: 131
Likes: 1
From: um....er.....
ylhelico.
Can I ask what operations you carry out?
I'm just intrigued by your reasoning with regards to confined areas & submerging your tail.
On a personal note I've never had to go in a confined area small enough that my tail rotor was at risk & I certainly have never had my tail rotor threatened by water.
However interesting reading. Have always wondered ref. Notar vs Tail Rotors (After all I've encountered tail rotor problems!
)
Does the above info. have any relevance to the 900's & 902 aswell?
For the record, I still fly conventional machines & have yet to get my grubby mits on a NOTAR!
Can I ask what operations you carry out?
I'm just intrigued by your reasoning with regards to confined areas & submerging your tail.
On a personal note I've never had to go in a confined area small enough that my tail rotor was at risk & I certainly have never had my tail rotor threatened by water.
However interesting reading. Have always wondered ref. Notar vs Tail Rotors (After all I've encountered tail rotor problems!
)Does the above info. have any relevance to the 900's & 902 aswell?
For the record, I still fly conventional machines & have yet to get my grubby mits on a NOTAR!
Joined: May 2001
Posts: 1,691
Likes: 3
From: Escrick York england
after reading all of these posts i wonder if i have a md 600 at all and my friends that have one too they may not have one
there are posts from pprune rs that mentions 500 /520 i thought this thread was about 600 s
i own and fly one i find it a joy to fly ,cheap to maintain,good value for money, reliable, [note it does less time in the maint hangar than some friends i know that have 350/355 /341/ 407 /109/
maybe you should go and fly a 600 then comment every one that has been in mine likes it [i think]
rant over
there are posts from pprune rs that mentions 500 /520 i thought this thread was about 600 s
i own and fly one i find it a joy to fly ,cheap to maintain,good value for money, reliable, [note it does less time in the maint hangar than some friends i know that have 350/355 /341/ 407 /109/
maybe you should go and fly a 600 then comment every one that has been in mine likes it [i think]
rant over
Joined: Feb 2002
Posts: 14
Likes: 0
From: Canada
To CTD
- A truck, that how we call the notar.
- The difference with the Notar is that when you increase the torque, the anti-thrust increase at the same time because of the increased coanda effect. So you don't need to move the pedals as much as with a conventionnal helo.
Also, with no tail rotor, you're less likely to encounter tail rotor vortex problems.
To Roofus
- For the water: It happened to my partner, he was landed on a beaver dam at 100% and waiting after a passenger when the dam broke down under the weight of the helo. By the time he pulled anought power to hold it up, the tail cone was touching the water.
- During diamonds surveying, we land in swamps 50 times a day and sometime it is somehow dirty. But you always have the choice to land or not. With a notar you just have a bigger selection of areas.
- A truck, that how we call the notar.
- The difference with the Notar is that when you increase the torque, the anti-thrust increase at the same time because of the increased coanda effect. So you don't need to move the pedals as much as with a conventionnal helo.
Also, with no tail rotor, you're less likely to encounter tail rotor vortex problems.
To Roofus
- For the water: It happened to my partner, he was landed on a beaver dam at 100% and waiting after a passenger when the dam broke down under the weight of the helo. By the time he pulled anought power to hold it up, the tail cone was touching the water.
- During diamonds surveying, we land in swamps 50 times a day and sometime it is somehow dirty. But you always have the choice to land or not. With a notar you just have a bigger selection of areas.
Joined: Apr 2002
Posts: 199
Likes: 0
From: oceanside
md 600 plenum chamber cracks
re: md 600 plenum chamber:
cracks found on p/n: 369H3042-11 spray assy water wash. 3 seperate a/c all with approx 3000TT. spray assy cracked radially around plate / wash fitting weld. potential for engine fod is high, replaced with new fittings, have detailed jpeg if so desired.
chopperdr
cracks found on p/n: 369H3042-11 spray assy water wash. 3 seperate a/c all with approx 3000TT. spray assy cracked radially around plate / wash fitting weld. potential for engine fod is high, replaced with new fittings, have detailed jpeg if so desired.
chopperdr
Thread Starter
Joined: Apr 2001
Posts: 113
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From: SoCal
Also watch out for off field landings in the MD600. The alt. air door does not remain sealed properly with high power settings, allowing dirt, sand and stuff in. Effectively bypassing the filter.
We are restricted from landing off heliport due to FODing 4 engines.
We are restricted from landing off heliport due to FODing 4 engines.
Joined: Sep 2002
Posts: 95
Likes: 0
From: usa
HeliMark,
The U.S. Border Patrol (who operate 10 MD600s) have retrofitted their aircraft with a barrier filter in place of the standard particle seperator. They operator low in desert conditions, probably the worst conditions of any 600 operator, and are seeing a lot less erosion on the compressor blades. They also see an average of 15 degrees lower operating temperatures.
The U.S. Border Patrol (who operate 10 MD600s) have retrofitted their aircraft with a barrier filter in place of the standard particle seperator. They operator low in desert conditions, probably the worst conditions of any 600 operator, and are seeing a lot less erosion on the compressor blades. They also see an average of 15 degrees lower operating temperatures.