BK117
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PANews,
I see once again you are suddenly the expert on this matter.
Quote: "Giovanni you said categorically the BK117 gearbox was made by ZF in Germany."
No, he said "Last time I looked the BK117 gearbox was made by ZF in Germany."
Last time he looked! Main, intermediate or TR ? You cannot assume he knows you are talking about MRGs
ZF make intermediate and tail rotor gearboxes and overhaul MGBs for the 117.
Quote: "It may be that some models of the BK have ZF boxes, but as far as the thread goes this is a Kawasaki box thread ['bad press on Kawasaki gearbox failures']".
Is that why it is titled " BK117 gearboxes"?
Gio doesn't know you have a thing for MRGs, just that you tell him he is wrong, when he is correct in what he says.
Quote: "in which posting did you actually get around to twisting quoted words of 'Silsoe Kids comment' into the slightly emotive .... 'kids comment'"
As in the words, kids and comment being next to each other in the same sentence with no punctuation between them!
You may call ZF a red herring if you wish, because it suits your argument, but I would suggest you cease telling others they are wrong when you haven't seen what they may have.
ATB,
SS
I see once again you are suddenly the expert on this matter.
Quote: "Giovanni you said categorically the BK117 gearbox was made by ZF in Germany."
No, he said "Last time I looked the BK117 gearbox was made by ZF in Germany."
Last time he looked! Main, intermediate or TR ? You cannot assume he knows you are talking about MRGs
ZF make intermediate and tail rotor gearboxes and overhaul MGBs for the 117.
Quote: "It may be that some models of the BK have ZF boxes, but as far as the thread goes this is a Kawasaki box thread ['bad press on Kawasaki gearbox failures']".
Is that why it is titled " BK117 gearboxes"?
Gio doesn't know you have a thing for MRGs, just that you tell him he is wrong, when he is correct in what he says.
Quote: "in which posting did you actually get around to twisting quoted words of 'Silsoe Kids comment' into the slightly emotive .... 'kids comment'"
As in the words, kids and comment being next to each other in the same sentence with no punctuation between them!
You may call ZF a red herring if you wish, because it suits your argument, but I would suggest you cease telling others they are wrong when you haven't seen what they may have.
ATB,
SS
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G'day Gents ....
Right ... the Bk117 main transmission is manufactured by Kawasaki and was jointly designed by MBB and Kawasaki Heavy industries.
The Intermediate (42 degree box) and the T/R (90 degree box) were lifted from the Bo105 series machines and are manufactured by ZF (ZandfabrikFreidrichafen) in Germany.
The Bo105 used either the ZF72 or the ZF112 main Xmsn depending on the model (and or the military?).
They are all Bulletproof! (providing of course you don't use too big a bullet!!).
Cheers .....
Right ... the Bk117 main transmission is manufactured by Kawasaki and was jointly designed by MBB and Kawasaki Heavy industries.
The Intermediate (42 degree box) and the T/R (90 degree box) were lifted from the Bo105 series machines and are manufactured by ZF (ZandfabrikFreidrichafen) in Germany.
The Bo105 used either the ZF72 or the ZF112 main Xmsn depending on the model (and or the military?).
They are all Bulletproof! (providing of course you don't use too big a bullet!!).
Cheers .....
ZF: the black hole of gearbox overhaul 
My MGB was lost there for three months, and TRGB for two months 
My MGB had to go to EID for overhaul, who then had to send it to ZF, whereupon it disappeared. The TRGB was an even worse drama
Re the 117 MGB, my understanding is that Kawasaki have the design approval, but (all) the MGB's are assembled by ZF, regardless whether they go into a KHI or a Eurocopter BK. Check any 117 MGB, look for European inscriptions from the production line checks (crossed 7's, funny shaped 1's, etc) by the Inspectors.
KHI having design approval is a nightmare, nothing gets done in a hurry coming out of Japan. European 117's have many advantages over the Japanese built units: eg any KHI service must incorporate ALL previous lower hour services at the same time, ie a 1200 hour must include a 600, 300, 150 and a 50 hour inspection, even if they're done out of sequence European servicing allows far more latitude, for the same airframe 
My MGB was lost there for three months, and TRGB for two months My MGB had to go to EID for overhaul, who then had to send it to ZF, whereupon it disappeared. The TRGB was an even worse drama Re the 117 MGB, my understanding is that Kawasaki have the design approval, but (all) the MGB's are assembled by ZF, regardless whether they go into a KHI or a Eurocopter BK. Check any 117 MGB, look for European inscriptions from the production line checks (crossed 7's, funny shaped 1's, etc) by the Inspectors.
KHI having design approval is a nightmare, nothing gets done in a hurry coming out of Japan. European 117's have many advantages over the Japanese built units: eg any KHI service must incorporate ALL previous lower hour services at the same time, ie a 1200 hour must include a 600, 300, 150 and a 50 hour inspection, even if they're done out of sequence
European servicing allows far more latitude, for the same airframe
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John , how have ZF been for cost ? , if i recall correctly their "standard" overhaul has so many terms and conditions that virtually every box would end up with loads of over and above charges.
Widge,
Horrible! The TRGB was returned having seized (on the bench, after removal) witnessed by Eurocopter engineers. After 2-3 months the bill for $US4,000 arrived, "no fault found", pay before we give you your box back. Some terse exchanges resulted in a more detailed inspection, and a repaired GB arrived back without much further explanation. Shortly after, an AD was issued recalling all TRGB's with the bearing that failed on my box
Fortunately the Kiwi's are looking like being able to do the overhauls in future
Horrible! The TRGB was returned having seized (on the bench, after removal) witnessed by Eurocopter engineers. After 2-3 months the bill for $US4,000 arrived, "no fault found", pay before we give you your box back. Some terse exchanges resulted in a more detailed inspection, and a repaired GB arrived back without much further explanation. Shortly after, an AD was issued recalling all TRGB's with the bearing that failed on my box
Fortunately the Kiwi's are looking like being able to do the overhauls in future
Been quiet a while here guys, but I would like to renew discussion on the BK117 pitch up at High AUW/DA/IAS.
Hingeless Rotors and splitpin, you say you have both experienced the pitch up, and splitpin claims it a regular occurence. What interests me here is the cruise power you are setting.
Do you cruise with TQ at 60 matched or 70 matched/top of the green?
The reason I ask is that some of the pilots I have spoken to with considerable BK time (in excess of 3000 hours) have never experienced it, and yet other pilots with far fewer hours have seen it more than once. The only obvious difference I can see that would relate to the pitch up is the TQ settings (High TQ is indicative of higher blade pitch angles and higher forward speed). The pilot's whom have experienced this were using 70% matched or top of the green. The others were using 60% matched for cruise.
To my knowledge, the flight manual, tech notes, training notes, nor checklist indicate that pilots should use any particular TQ setting for the cruise. It seems that from the original German Test pilot who recommended 60% matched, that is the convention here in Oz passed from endorsement to endorsement. Except that some people have not had that exposure, and have no written advice either, thus they are using 70%/top of the green as per every other helicopter.
Has anyone experienced this pitchup below 8000 ft DA, below 70% TQ setting or below VNE - 10kts?
Hingeless Rotors and splitpin, you say you have both experienced the pitch up, and splitpin claims it a regular occurence. What interests me here is the cruise power you are setting.
Do you cruise with TQ at 60 matched or 70 matched/top of the green?
The reason I ask is that some of the pilots I have spoken to with considerable BK time (in excess of 3000 hours) have never experienced it, and yet other pilots with far fewer hours have seen it more than once. The only obvious difference I can see that would relate to the pitch up is the TQ settings (High TQ is indicative of higher blade pitch angles and higher forward speed). The pilot's whom have experienced this were using 70% matched or top of the green. The others were using 60% matched for cruise.
To my knowledge, the flight manual, tech notes, training notes, nor checklist indicate that pilots should use any particular TQ setting for the cruise. It seems that from the original German Test pilot who recommended 60% matched, that is the convention here in Oz passed from endorsement to endorsement. Except that some people have not had that exposure, and have no written advice either, thus they are using 70%/top of the green as per every other helicopter.
Has anyone experienced this pitchup below 8000 ft DA, below 70% TQ setting or below VNE - 10kts?
Last edited by helmet fire; 13th Dec 2005 at 07:49.
HF,
Yes, to all three.
As you said, there is no recommended Tq setting for cruise in the BK, and I have a peculiar habit of using 62%: it's what I used in the S61 and 212, and seems convenient
At that setting I've had pitch up at DA's above 5000' in cruise at 120kias, and at lower speeds. Mountain turbulence has been a factor on most occasions, and sometimes my speed has been down around 100kias.
Just one of those things that you learn to anticipate, and live with.
Yes, to all three.
As you said, there is no recommended Tq setting for cruise in the BK, and I have a peculiar habit of using 62%: it's what I used in the S61 and 212, and seems convenient
At that setting I've had pitch up at DA's above 5000' in cruise at 120kias, and at lower speeds. Mountain turbulence has been a factor on most occasions, and sometimes my speed has been down around 100kias.Just one of those things that you learn to anticipate, and live with.
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I also think that the reason for the "lower" Tq settings for the BK (at least in the early years in Oz) was to nurse the LTS101 along a bit easier.
That was when it wasn't working too well - but at least in the BK it was working alot better than the USCG Dolphins and 222's due to the lower output speeds.
The only problem now with using MCP in cruise is that it can get a little thirsty on the fuel and a little too bumpy if you do get alot of turbulence at high speeds.
That was when it wasn't working too well - but at least in the BK it was working alot better than the USCG Dolphins and 222's due to the lower output speeds.
The only problem now with using MCP in cruise is that it can get a little thirsty on the fuel and a little too bumpy if you do get alot of turbulence at high speeds.
John and oogle, thanks for the replies. Oogle, did you experience the pitch up?
John, I just want to clarify what I mean by the pitch up. I am not talking about pitching due to turbulence ie the pitch rate is uncomfortable, harsh, and "normal" given the fact that you are in turbulence and in a ridgid rotor head. This pitch up is associated with other tubulent movements of rolling and pitching down. And it is controlable with cyclic. IFR ships seem to experience a solid pitch up in turbulence when driven by the autopilot, but this can be overcome easily by cyclic.
I am talking about a pitch up phenomena that occurs quickly and unexpectedly and is not controllable by cyclic alone. It, as far as I can gather from those whom have experienced it, often results in a nose up of more than 40 degrees and can be accompanied by hitting the forward cyclic limit, and can even produce a steady red on the most moment indicator. It seems to be best remedied by reduction of collective rather than persisting with cyclic.
John, I just want to clarify what I mean by the pitch up. I am not talking about pitching due to turbulence ie the pitch rate is uncomfortable, harsh, and "normal" given the fact that you are in turbulence and in a ridgid rotor head. This pitch up is associated with other tubulent movements of rolling and pitching down. And it is controlable with cyclic. IFR ships seem to experience a solid pitch up in turbulence when driven by the autopilot, but this can be overcome easily by cyclic.
I am talking about a pitch up phenomena that occurs quickly and unexpectedly and is not controllable by cyclic alone. It, as far as I can gather from those whom have experienced it, often results in a nose up of more than 40 degrees and can be accompanied by hitting the forward cyclic limit, and can even produce a steady red on the most moment indicator. It seems to be best remedied by reduction of collective rather than persisting with cyclic.
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I flew one for about ten years and have never experienced the aircraft pitching up uncommanded.
Though having said that, I flew with a chap who did, and in recovery over pitched nose down. In recovering from the pitch down he took out part of the vertical stabilisers with the main rotor. (He stated the nose up movement felt like going vertical nearly rolling onto it's back)
The pilot involved gave up flying after the experience.
He also associated it with turbulence.
Though having said that, I flew with a chap who did, and in recovery over pitched nose down. In recovering from the pitch down he took out part of the vertical stabilisers with the main rotor. (He stated the nose up movement felt like going vertical nearly rolling onto it's back)
The pilot involved gave up flying after the experience.
He also associated it with turbulence.
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Helmet Fire
I have not experienced the pitch up that you mention. Mind you, most of my time up at the altitudes that you mention is enroute IFR. The autopilot has caused a couple of hiccups but nothing to write home about. Fire bombing for a number of seasons but at relatively lower altitudes than you mention.
Certainly the inflow roll problems associated with a low level trun to the right. I have the bruises on my left knee to prove it. You can get the same inflow roll problem (running out of left cyclic) with a steep approach with a wind from the left.
That being said - I love the BK.
I have not experienced the pitch up that you mention. Mind you, most of my time up at the altitudes that you mention is enroute IFR. The autopilot has caused a couple of hiccups but nothing to write home about. Fire bombing for a number of seasons but at relatively lower altitudes than you mention.
Certainly the inflow roll problems associated with a low level trun to the right. I have the bruises on my left knee to prove it. You can get the same inflow roll problem (running out of left cyclic) with a steep approach with a wind from the left.
That being said - I love the BK.
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Helmet,
I have experienced the pitch up phenomenon around 3 or 4 times in my 2500 hrs BK. All were during IFR operations and normally preceded by a bump due turbulance.
It is quite an insideous little problem that once started you need to react quickly before you go past 20 degrees nose up. When it first happened I put in a correcting input that just wasn't enough and felt as if I was chasing it all the way to the stops.....
It dosn't take long before you can pick when it is going to happen and apply a decent correction to snuff it out.
I normally fly around at 60% tq and matched about 98%nr due to the cycle count issues. Usually we are at Max T/O but only around 4000 DH.
I believe the child flight guys in Sydney (oz) had a ripper of a nose up situation that gave them all the willies.
I have not experienced the problem in any B2's I have flown.
Cheers
I have experienced the pitch up phenomenon around 3 or 4 times in my 2500 hrs BK. All were during IFR operations and normally preceded by a bump due turbulance.
It is quite an insideous little problem that once started you need to react quickly before you go past 20 degrees nose up. When it first happened I put in a correcting input that just wasn't enough and felt as if I was chasing it all the way to the stops.....
It dosn't take long before you can pick when it is going to happen and apply a decent correction to snuff it out.
I normally fly around at 60% tq and matched about 98%nr due to the cycle count issues. Usually we are at Max T/O but only around 4000 DH.
I believe the child flight guys in Sydney (oz) had a ripper of a nose up situation that gave them all the willies.
I have not experienced the problem in any B2's I have flown.
Cheers
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Hingeless
The CF machine IS a B2
Are you coupled to the autopilot on all your experiences? If so, I think its a problem with the autopilot. In all the autopilot machines I've flown, you can get the autopilot giving what you mentioned and after some headscrathching, it has always been a problem with the autopilot system. Not necessarily with the aircraft type.
BUT, you never know what an aircraft is going to throw at you!
The CF machine IS a B2
Are you coupled to the autopilot on all your experiences? If so, I think its a problem with the autopilot. In all the autopilot machines I've flown, you can get the autopilot giving what you mentioned and after some headscrathching, it has always been a problem with the autopilot system. Not necessarily with the aircraft type.
BUT, you never know what an aircraft is going to throw at you!
Taken from another web site
I have flown BK's with and without the pitch and roll sas. The ones without, at high speed about ten knots less than vne, you start to feel a sort of buffeting which is a symptom of the onset of retreating blade stall. If you reduce pict and slow down it goes away. i worked with a pilot that had a violent pitch up(rt=etreating blade stall) of this aircraft twice. The aircrat i flew with the pitch sas never felt like it was on the edge, but that doesn't mean it wasn't. In this ship I once experienced a pitch up of the nose in level cruise flight. I had full forward cyclic, to the stop and it didn't stop until I lowered collective. I think this had something to do with the spas system not working properly. The spas is something of interest read up on it.
Have any of you done much external cargo work with the BK117?
At sea level we can lift 1300kg on the hook with 150kg of fuel without any problems, and at 7-8000' DA a good working load is 1000 - 1100kg, depending on fuel load. We shift quite a bit of concrete in aluminium kibbles during ski field construction work, usually on a 100'/30 metre line: the pilot's seat is too far in from the floor to make it a good VR lifter, but as with all things, you get used to it. The BK seems to lift better the longer the line: on fire work, it certainly pulls water in a Bambi more easily and with less power on a 100' line than with the Bambi on the hook. I don't know why, but I reckon there's a 5% Tq difference between the two.
Dspice, can you start another thread on the external load issues, as I would really like to get to the bottom of the pitch up?
John, I am still asking above about the pitch up clarification if you can?
Has anybody experienced this pitch up with SPAS inoperable?
I am wondering if we might list the occurances of this pitch up that we can find out about? Remember I am talking about a pitch up that is not overcome by full forward cyclic unless collective is lowered. I am not talking about the normal ridgid rotor head reaction to tubulence bumping.
I am collecting as much info as possible on this to examine a recent occurance, and would appreciate all your info.
Occurences:
1. Australia in Dec 2005, Japanese BK117 B2. 7000 ft hp, 20 deg C. 3180 kg. 70% TQ. 120 kts IAS. SPIFR autopilot machine but being handflown in SAS mode. Turbulence present, and it ws also preceeded by a smaller pitch up bump that was controllable. Extrapolating chart VNE equals 125 kts IAS in this config.
SASless, can you fill your details in?
Hingeless, can you remember your specifics?
Oogle fire bombing speeds are generally well below VNE, particularly with bambi limits.
Blade root: have you got the specifics of the CF incident?
John, I am still asking above about the pitch up clarification if you can?
Has anybody experienced this pitch up with SPAS inoperable?
I am wondering if we might list the occurances of this pitch up that we can find out about? Remember I am talking about a pitch up that is not overcome by full forward cyclic unless collective is lowered. I am not talking about the normal ridgid rotor head reaction to tubulence bumping.
I am collecting as much info as possible on this to examine a recent occurance, and would appreciate all your info.
Occurences:
1. Australia in Dec 2005, Japanese BK117 B2. 7000 ft hp, 20 deg C. 3180 kg. 70% TQ. 120 kts IAS. SPIFR autopilot machine but being handflown in SAS mode. Turbulence present, and it ws also preceeded by a smaller pitch up bump that was controllable. Extrapolating chart VNE equals 125 kts IAS in this config.
SASless, can you fill your details in?
Hingeless, can you remember your specifics?
Oogle fire bombing speeds are generally well below VNE, particularly with bambi limits.
Blade root: have you got the specifics of the CF incident?
Last edited by helmet fire; 15th Dec 2005 at 22:13.
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Helmet,
Yes I can remember the specifics.....
All but one BK I have flown were two pilot so I don't think the autopilot is the problem.
In every occurance it was preceded by turbulence. If you react fast enough, you can counter the effect.
I originally thought it was a SPAS problem, but can't bring myself to blame it as I basically have no idea.
I havn't had a BK do it now for years as I really do believe that you can predict the reaction and put in the controlling inputs to reduce it well in advance, although I have to admit that the input is larger than normal.
Oogle,
Honestly, I think it is a BK issue as apposed to an autopilot one. I have only ever flown one with an autopilot, didn't have any probs with it but I only got to drive it for a short time. I might have to amend my comment on not experienceing it in B2's, now that I think of it, the early occurences may well have been in a B2. The CF story puts that one to rest anyway.
Cheers
Yes I can remember the specifics.....
All but one BK I have flown were two pilot so I don't think the autopilot is the problem.
In every occurance it was preceded by turbulence. If you react fast enough, you can counter the effect.
I originally thought it was a SPAS problem, but can't bring myself to blame it as I basically have no idea.
I havn't had a BK do it now for years as I really do believe that you can predict the reaction and put in the controlling inputs to reduce it well in advance, although I have to admit that the input is larger than normal.
Oogle,
Honestly, I think it is a BK issue as apposed to an autopilot one. I have only ever flown one with an autopilot, didn't have any probs with it but I only got to drive it for a short time. I might have to amend my comment on not experienceing it in B2's, now that I think of it, the early occurences may well have been in a B2. The CF story puts that one to rest anyway.
Cheers