Ch-47 Chinook - Shipboard Capabilities

[baboon6]

The Royal Navy has a relatively small (28 000 ton, 173metre) RO/RO and container ship, converted to an "aviation support ship", RFA Argus (ex-Contender Bezant). She is used as an aviation transport, aircrew training ship, combat transport, auxiliary aircraft carrier and hospital ship. Argus can operate up to 6 Sea Kings and 8 Harriers and can carry 750 troops. I'm sure it is plausible for Canada to convert a bigger ship for more varied roles as have been detailed above- troop and vehicle transport, helicopter platform.

 

[YukonJack]

I've seen the Chinook landed on the flight deck of Provider, athwartships of course....Protecteur and Preserver are supposed to have similar-sized decks. Just a point of note for the original post.

 

[SeaKingTacco]

I've seen the Chinook landed on the flight deck of Provider, athwartships of course

I highly doubt it.  I just rechecked my copy of HOSTACs (NATO helicopter operations for ships other than Aircraft carriers) and no Canadian Ship is certified for the Chinook.  During Op Apollo, Canadian Ships did receive certification for the Sea Knight, however.

There are two main problems with Chinooks at sea.  The first is that Canadian Flight decks are only stressed for about 25,000lbs, which is not good when you consider an empty Chinook weighs in at around that mark.  A full one tips the scale at about 50,000lbs (by comparison, a fully loaded Sea King weighs in at 20,500 lbs.  A deck weight limit is probably fixable with a refit (or in the design of a new ship class) and it is something we will have to do any way so that the frigates can finish their lives with CH-148 Cyclones onboard.

The second problem with Chinooks is that they are not, and have never been, marinized.  This is not inconsequential.  Even fully marinized helos such as the Sea King (which are built in the factory with special paints coating construction techniques which limit the damage a humid and salty environment will have on an aircraft) still require an awesome amount of attention at sea to prevent corrosion or avonics problems.  Anecedotal evidence from the UK and US military has suggested to me that they were not all that happy with the results of operating Chinooks from ships, because they were not designed to be operated in that environment.  This also is to say nothing of the lack of an automatic blade folding system...

I hope that before we rush headlong down the "Chinook road", with an intention of operating them from ships, that we (I mean DAR in Ottawa) do some basic research about just how well that would actually work.

Just my two cents worth.

 

[YukonJack]

: Doubt all ya' want, sunshine....

 

[Inch]

: Doubt all ya' want, sunshine....

Yes, you're right then, the HOSTAC doesn't always know what aircraft can land on which ships, oh wait, that's what it's written for.

I haven't looked at the HOSTAC yet, but that's the publication that will state whether or not a Chinook can land on any of our ships, SKT checked it and it said that none of our ships could support it, so I guess the HOSTAC and him are wrong eh?

 

[Good2Golf]

I highly doubt it.  I just rechecked my copy of HOSTACs (NATO helicopter operations for ships other than Aircraft carriers) and no Canadian Ship is certified for the Chinook.  During Op Apollo, Canadian Ships did receive certification for the Sea Knight, however.

There are two main problems with Chinooks at sea.  The first is that Canadian Flight decks are only stressed for about 25,000lbs, which is not good when you consider an empty Chinook weighs in at around that mark.  A full one tips the scale at about 50,000lbs (by comparison, a fully loaded Sea King weighs in at 20,500 lbs.  A deck weight limit is probably fixable with a refit (or in the design of a new ship class) and it is something we will have to do any way so that the frigates can finish their lives with CH-148 Cyclones onboard.

The second problem with Chinooks is that they are not, and have never been, marinized.  This is not inconsequential.  Even fully marinized helos such as the Sea King (which are built in the factory with special paints coating construction techniques which limit the damage a humid and salty environment will have on an aircraft) still require an awesome amount of attention at sea to prevent corrosion or avonics problems.  Anecedotal evidence from the UK and US military has suggested to me that they were not all that happy with the results of operating Chinooks from ships, because they were not designed to be operated in that environment.  This also is to say nothing of the lack of an automatic blade folding system...

I hope that before we rush headlong down the "Chinook road", with an intention of operating them from ships, that we (I mean DAR in Ottawa) do some basic research about just how well that would actually work.

Just my two cents worth.

SKT, "certification" and "it being done" are two different things -- I recall looking through 450 Sqn's history books and distinctly recall pics of a hook on an AOR...couldn't tell you if it was Provider, Preserver, Protecteur...I think it was some time in the mid-80's.

Re: deck loading on CPF...what is the load factor for the flight deck, i.e.  Lbs/Sq.ft.?  I would venture to say that a Sea King at AUW being hauled down by the bear trap will exert a wee bit more than 25,000 lbs...even a 1.5G downhaul would exceed 25,000lbs absolute, would it not?  A Chinook spreads its maximum 55,000lbs over six tires, four mounts, in fore/aft pairs spread 40 ' apart.  30,000lbs for weight on main mounts of an S-92...I think you'll see where I'm heading with this one...

"not marinized".....I think you meant to say "not FULLY marinized"...I would venture to say that with about 5 hours of time dipping, swimming, casting zodiacs, etc... in the water, I have more time with a helicopter sitting in the water...both fresh and salt water than many if not most Sea King guys.  Seeing 406 taped up flailing around the Bedford Basin, folding blades aside, makes me really wonder how "marinized" the SK actually was. ???  The entire lower half of the 'Hooks fuselage is zinc chromated.  Freshwater wash for engines and the fuselage would be done to a SeaKing/Cyclone as well, would it not.  So the real issue is whether auto/self-powered blade foldeing is an essential or only a highly-desireable requirement -- also, what will the shipborne CONOPS be? 

UK, US not happy?  That's funny, I have the US JSHIP report and have spoken with 3/160 guys who were quite content with op'ing off ships...well, them and the OH-58D guys.

SKT, have no fear...the DAR 9 guys are very aware of the issues.

So, what does this all mean?

Well....here's my take on the whole issue.  We (me and my 47 buds) will be so busy flying our arses off 350km South of where I am right now, as well as supporting "other units" in Canada, that we won't even be used as part of the SCTF and we will rarely, if ever, operate from an HMCS the way some people appear to be expecting us to.  Personally, I think that the SCTF Comd will just have to make do with the CH148 and its "fully marinized but lacking in other significant areas" capability when it comes to lifting troops off the big honking ship and taking them inland. 

My 1 Afghani (=2 ¢)

Cheers,
Duey

 

[Inch]

Duey,

I'm pretty sure that the Sea King at all up weight still touches down at around 20,500 lbs force on the deck. We land at up to 8 fps while on the wire, usually less though since anything over 8 fps counts as a hard landing. Even still, at 8 fps I'd be surprised if it really puts that much force on the deck, the oleos and tires would take most of the impact I would think.

I can tell you for certain though, each ship has an all up weight maximum that must be adhered to, perhaps this number already takes into account the landing force inflicted on the deck when you touch down, I can't say for certain.

Anyway, I'm off to the airport, embarking the helo and bound for the Bahamas. See you all in a few weeks.

 

[SeaKingTacco]

Duey,

Look, I'm not advocating one helo over another.  I just been following the thread (and others) where alot of guys who have never flown a helicopter, much less from a ship are making alot of assumptions that may or may not be correct.  All that I am really saying is that IF we are going to buy the Chinook (or S-92, or CH-53) as a troop lifter with the intention of operating it from a ship, let us make sure have done our homework.  It may be that trying to buy one helo to do everything again, is going to leave us unhappy in the long run...

Re: Chinooks on a Canadian deck: If you say that you have seen it, I bow to your obvious credibility in this area.  That said, it is not in HOSTACs and therefore not legal outside of a trial or experimental setting.

Deck weight limits:  I've spoken to several Ship's engineering officers about this.  The weight limit for our decks is based on a 25,000 lb wheeled helicopter landing at 8ft/sec (if I remember correctly), which does indeed exceed an absolute static weight limit of 25,000 lbs.  As I said earlier, the intention always was to strengthen the deck for the S-92 (a 30,000lb helo) , and will form part of FELEX. 

Waterbird:  Duey, any Sea King in the fleet is fully capable of floating.  The only reason that we tape up the "waterbird" is to make life easier for the techs at the end of the day by helping limit water ingress after 50-60 daily water landings and also to provide extra protection for the seals on various access panels.  The Sea King was designed with the salt water environment in mind, trust me. 

I agree with you about the Chinook.  If we get it, it will probably rarely if ever, see service on a HMC Ship.

Cheers, buddy!

 

[Good2Golf]

SKT, although I won't try to hide the fact that I'm somewhat biased towards the 'Hook, my points of clarification were primarily to try and curb some misconceptions out there, specifically the "not marinized" bit.  As I mentioned, in this post and others, I think the job over here for aviation is important and demanding enough, that I honest don't think we'll really see the TALC used for the SCTF.  I don't mean that as not wanting to contribute to that capability, but that the reality is that we'll only have so many of the heavy lifters and that most likely, manning will be fully taxed to support deployed operations over here.  I'm not even sure if heavy lift will ever qualify and stay current on the big honking ship...who know, I might be proven wrong.  Time will tell.

Cheers,
Duey

 

[SeaKingTacco]

Duey,

Now that we are in heated agreement (hey, it's just like the old days at Royal Roads, huh?), a question for ya:

Did the 3/160 guys you spoke with mention any INS problems with their Chinooks at sea?  Just curious, because an often overlooked problem with helos that did not start out with shipborne operations in mind is getting the INS to erect while the ship is turning, deck is moving, etc. 

Cheers!

 

[Good2Golf]

Duey,

Now that we are in heated agreement (hey, it's just like the old days at Royal Roads, huh?), a question for ya:

Did the 3/160 guys you spoke with mention any INS problems with their Chinooks at sea?  Just curious, because an often overlooked problem with helos that did not start out with shipborne operations in mind is getting the INS to erect while the ship is turning, deck is moving, etc. 

Cheers!

SKT,  I don't think the -G's have INS per se, just AHRS (spin up much faster since not near the long-term accuracy INS has) -- also DGPS and a few other...ummm...."RNAV-ish" system onboard.

Cheers,
Duey

 

[Infanteer]

INS....AHRS....DGPS...."RNAV-ish"

HUH?

 

[SeaKingTacco]

HUH?

The thingy which tells you which direction you are flying in and whether or not you are upside-down 

Duey,

Thanks for the AHRS info.  All is clear now.

Cheers.

 

[aesop081]

HUH?

Welcome to our world.........

 

[Good2Golf]

Infanteer,

INS - inertial navigation system: very sensitive accelerometers keep track of where a platform is but integrating its accelerations in all three linear axes.  It takes a while for the gyros to wind up (even laser gyros) and it takes longer to spin up ("erect" believe it or not) when the platform is moving around (as on a ship) or the higher North you go (due to less induced gyroscopic precession towards either of the Earth's pole)

AHRS - attitude - heading - reference system (a cheaper, less accurate version of an INS) primarily used in helicopters with a shorted flight endurance than long-range a/c such as Aurora or Herc (both with INS).

DGPS - differential GPS.  There are a couple different modes of DGPS operation but in this case, the idea is to determine a difference between two GPS sets on the same platform.  While non-P/Y code is roughly accurate to 16-30m depending on SA accuracy, and even Y-code GPS still only officially gets to 6-10m for a single set, two GPS receivers in near proximity to each other can very accurately determine their different range from the same satellite compared to each other to a fraction of a centimeter...they may still be +/- 10m to the world but they know their relative geometry (from the installation on the platform) to each other and the satellite.  E.g.  if one GPS unit knows it's 1.46m further away from satellete 25 than the other receiver, and that the two receivers are 3.25m apart, the nav system could calculate that aircraft must be tilted ~35degrees to the right....bank angle known and you haven't even looked at an Artificial Horizon/gyro!  Add a third GPS reciever on the platform and you can know resolve orientation in all three axis to fractions of degrees AND you still have the LAT/LONG/ALT position resolution as well...all without and INS or AHRS.

RNAV - "aRea NAVigation" (don't ask why the R...must have been a drunk Navigator making the contraction )  Any kind of a system that can resolve your position to the required degree of accuracy.  Back before GPS, we used to use LORAN(-C) and OMEGA.  There are also astro-based RNAV systems and other systems that, shall we say, use very, very, accurate 3-D maps to determine, quite literally, where on earth" you are (think 12+ digit grid reference and accurate DTED (digital terrain elevation data) ).

Cheers,
Duey

 

[Michael OLeary]

HUH?

Reminds me of my Advanced Aviation Course: "Gentlemen, you are speaking in an alphabet that I do not understand."

 

[childs56]

DGPS as far as I know is not the differential between two GPS units. It is very similar to the old Lowrance system that was once used by Ships. The satellite or radio transmitter will send out a signal to the GPS receiver unit, this unit will calculate how much time the signal took to reach it and use that as a reference to its satellite position.As with all thing that use radio signals to calculate position the more the better.

Pretty much it takes the radio signal that it receives and correlates that with what the satellite fix from your GPS says you are. The more signals you receive from DGPS the more accurate you are. These radio signals can usually be manually changed by you the operator to correspond with different transmitter freq's in your area.

I doubt using two GPS receiver units in the same location will change your accuracy any, As I said above DGPS uses The GPS signal for a reference point and then radio transmission for a more accurate fix. The radio freq triangulate your position better, kinda like using a compass along with your GPS.

Hope I haven't confused any one here, or worse made any one mad, just wanted to help make more clear what DGPS is.  Most GPS;s have this abilities.

Cheers

 

[Good2Golf]

CTD, you have described another DGPS mode, often used to support LAAS or WAAS (local or wide-area accuracy augmentation system). 

The element of that particular system you're missing is that the differential capability is based on a separate GPS receiver installed in a very accurately surveyed position -- this bit is crucial to the accuracy of multi-platform DGPS.  The GPS receiver notes the difference between the true known position (surveyed) and what GPS signals tell its position to be.  The DGPS station then broadcasts a local or wide area correction signal, either through a separate RF channel (VHF-FM in some cases of marine systems) or in the 1100/1500MHz band acting as a "pseudolite" (using an assigned GPS channel but with a.  A moving platform-based DGPS-enabled receiver uses this correction signal to improve the accuracy of its own satellite-based solution -- commonly used for high accuracy around ports and harbours....being trialled in some cases as a precision aviation landing aid (can approach ILS-levels of accuracy). 

The single-platform DGPS solution I described needs only a differential baseline of a few meters to provide relatively accurate pitch, roll and yaw information in addition to the standard Lat, Long, Alt solution.  I know of several fixed-wing platforms that are equipped with the system as well as a few rotorcraft -- had a buddy write a 15,000 word paper on the system when we were on the Aerospace Systems Course in the Winterpeg.

As an aside, LORAN-C is a nav system that operates similarly to the multi-angulation of GPS but only in 2-D.

Cheers,
Duey

 

[childs56]

I thought you had meant that it required two separate GPS's mounted at certain points, instead of a GPS and a DGPS receiver which can be either mounted together or separate. I learned about these systems on A/C a few years ago, it intrigued me as to how accurate you can get. I mean you can tell every axis you are moving on, or for guys like me when you are lost it can tell you exactly where you are with in a foot or two.   
A good source for info on this stuff.
http://www.gpsinformation.org/dale/dgps.htm

Cheers.

 

[Good2Golf]

I thought you had meant that it required two separate GPS's mounted at certain points, instead of a GPS and a DGPS receiver which can be either mounted together or separate. I learned about these systems on A/C a few years ago, it intrigued me as to how accurate you can get. I mean you can tell every axis you are moving on, or for guys like me when you are lost it can tell you exactly where you are with in a foot or two.   
A good source for info on this stuff.
http://www.gpsinformation.org/dale/dgps.htm

Cheers.

It does, CTD. The separate signals from the dual antennas (or in some cases triple antennas) are fused by a multichannel GPS receiver and the AMS (avionics management system) to resolve the aircraft's pitch, roll and yaw.

Cheers,
Duey