Max Q
Topic Author
Posts: 5695
Joined: Wed May 09, 2001 12:40 pm

Difference Between CH47 Chinook And CH46 S Knight

Sun Sep 07, 2008 4:24 am

Are these two helicopters different versions of the same airframe ?
The best contribution to safety is a competent Pilot.
 
UH60FtRucker
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RE: Difference Between CH47 Chinook And CH46 S Knight

Sun Sep 07, 2008 5:16 am

Ah, no.

Two completely different aircraft, who both happen to be tandem rotor helicopters.

As much as I loath globalsecurity, the website actually has some photos depicting the difference:







Not to mention a host of significant differences underneath the skin. ..but really, who cares? The real men fly Black Hawks.

-UH60
Your men have to follow your orders. They don't have to go to your funeral.
 
aeroweanie
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RE: Difference Between CH47 Chinook And CH46 S Knight

Sun Sep 07, 2008 5:25 am

The CH-47 is much larger than the CH-46. The CH-46 has a max GW of 24,300 lbs, while the CH-47D has a max GW of 50,000 lbs. The CH-47 has far more installed power and larger rotors too. About all they have in common is the general tandem rotor configuration.

In comparing them, what really struck me was how roomy the interior of a CH-47 felt after walking through the relatively cramped interior of the CH-46.

CH-46:

View Large View Medium
Click here for bigger photo!

Photo © Jian Rao



CH-47:

View Large View Medium
Click here for bigger photo!

Photo © Karl Drage

 
bhmbaglock
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RE: Difference Between CH47 Chinook And CH46 S Knight

Sun Sep 07, 2008 6:03 am

Other than size, here are a few very notable differences:

CH-46(some models) have power blade folding for shipboard operations

CH-46 has tricycle landing gear vs quad for the CH-47

The CH-47 can land in water unmodified, installation of a dam is typically used if the ramp will be opened unless recovering or deploying a boat. The CH-46 requires inflatables to be able to land in water, ironic considering the 46 was primarily sold to naval customers and the 47 primarily to the Army. The sponsons on the CH-47 provide the stability required for this.

CH-47 has a much more advanced external carriage system for slung loads

Although both models were developed in parallel (a lot like 757/767) they have diverged a lot over time. The US Army has put much more money into modernizing the CH-47 and acquisitions are ongoing while the CH-46 is being phased out as the V-22 replaces it.

The size of the CH-47 also allows more versatility, i.e. more avionics room, room for weather radar, TFR, gunship mods, etc.

Here's a good summary of the programs: http://www.vectorsite.net/avch47.html
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Max Q
Topic Author
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RE: Difference Between CH47 Chinook And CH46 S Knight

Sun Sep 07, 2008 6:15 am

Thanks for the great information.
The best contribution to safety is a competent Pilot.
 
AirRyan
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RE: Difference Between CH47 Chinook And CH46 S Knight

Tue Sep 09, 2008 2:44 am

Same principle tandem rotor design, and ultimately the same manufactuer in Boeing-Vertol, but different class of helicopters.
 
dragon6172
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RE: Difference Between CH47 Chinook And CH46 S Knight

Tue Sep 09, 2008 10:21 am



Quoting UH60FtRucker (Reply 1):
..but really, who cares? The real men fly Black Hawks.

Ugh.. what a piece of junk. It was amazing to me how much of a pain in the ass the H-60s were that came to replace a Phrog squadron. Needed three of them to do what two Phrogs could do. Now, I share a hanger with a Navy H-60 unit and their birds are constantly needing repairs due to massive cracks where the transmissions mounts. Phrogs Phorever!!

Quoting BHMBAGLOCK (Reply 3):
The CH-47 can land in water unmodified, installation of a dam is typically used if the ramp will be opened unless recovering or deploying a boat. The CH-46 requires inflatables to be able to land in water, ironic considering the 46 was primarily sold to naval customers and the 47 primarily to the Army. The sponsons on the CH-47 provide the stability required for this.

H-46 can land in water unmodified as well if you do not have the left gunners window open. Water landings, taxiing, and takeoffs used to be part of the flight training syllabus, but was removed due to the intense maintenance effort required post water landing.
The HEFS (helo emergency flotation system, the inflatable bags carried on the side) were there to keep the aircraft upright and afloat in the event of a controlled emergency water landing. For example, a transmission related emergency where you needed to land and shut down. They were labor intensive, added 300 lbs ( or one Marine) to the aircraft weight, and the velcro that held them closed constantly failed and allowed them to hang uninflated. By the time I got out they had become an item that was required at the commanders descretion. Typically only used when deployed on ship and carrying passengers.

Quoting BHMBAGLOCK (Reply 3):
CH-46(some models) have power blade folding for shipboard operations

All CH-46s have power blade fold. It does not always work, but the system is installed. BV-107, and KV-107s do not typically have the power blade fold. Much smaller and lighter rotor heads installed.
Phrogs Phorever
 
UH60FtRucker
Posts: 3252
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RE: Difference Between CH47 Chinook And CH46 S Knight

Tue Sep 09, 2008 12:16 pm

Quoting Dragon6172 (Reply 6):

Ugh.. what a piece of junk. It was amazing to me how much of a pain in the ass the H-60s were that came to replace a Phrog squadron. Needed three of them to do what two Phrogs could do. Now, I share a hanger with a Navy H-60 unit and their birds are constantly needing repairs due to massive cracks where the transmissions mounts. Phrogs Phorever!!

Well Dragon... sorry to lay the smack down.... but I clearly said BLACK HAWK. Yet you used the Sea Hawk for comparison!

And also, I said real men. Sea Hawks are flown by squids! So of course they don't know how to properly run a H-60 unit! ....They're squid!!!     

----------------

No but in all seriousness, the early transmission mount cracks in the SH-60s have been resolved. The newer models featured the improvements, and the B models were retrofitted with the improved mounts.

Currently, fleet wide, they have an OCRR of 89%. Army UH-60Ls have a OCRR of 93%. Obviously with the saltwater environment and the rougher landing conditions, SH-60s require more attention, not to mention spare parts are harder to come by when you're at sea.

The Marines - who don't have H-60s - currently have a 70% OCRR for their CH-46s.

And to be fair... the Hawk does have a black eye - the USAF Pave Hawk has an OCRR of 54%.   (Hence the argument for a dire need for the new CSAR-X)

-UH60

[Edited 2008-09-09 05:26:11]
Your men have to follow your orders. They don't have to go to your funeral.
 
studedave
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RE: Difference Between CH47 Chinook And CH46 S Knight

Tue Sep 09, 2008 3:54 pm

I'll leave most of the comments directed at the NAVY by the door, because I know you kid around- just as do I from time to time. This, however, needs comment~

Quoting UH60FtRucker (Reply 7):
No but in all seriousness, the early transmission mount cracks in the SH-60s have been resolved. The newer models featured the improvements, and the B models were retrofitted with the improved mounts.

We've talked about all this before. Be careful when throwing that "SH" around- the "MHs" are the problem children~ Sierras in particular...
The Bravos, Foxtrots and Hotels are fine. Always have been- thery only have one cabin door. Sure they cracked once in a while, but not in the places (or as bad, or as early in life) as the Sierras. In fact alot of the older Bravos/Foxtrots are still flying- 20+ years later, and despite having flown well past their 'airframe life'! It's the "new" Sierras that are (were) having problems. With two cabin doors, the heavier duty drive train, and heavy work (VERTEP) combined with a weak structure- it didn't add up. Now throw an old Phrog Pilot in the cockpit, and it only gets worse!!!
There is finally a fix out there, but it wasn't too pretty while Sikorsky worked it out.
Classic planes, Classic trains, and Studebakers~~ what else is there???
 
dragon6172
Posts: 800
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RE: Difference Between CH47 Chinook And CH46 S Knight

Tue Sep 09, 2008 7:31 pm



Quoting UH60FtRucker (Reply 7):
Well Dragon... sorry to lay the smack down.... but I clearly said BLACK HAWK. Yet you used the Sea Hawk for comparison!

And also, I said real men. Sea Hawks are flown by squids! So of course they don't know how to properly run a H-60 unit! ....They're squid!!!

Allow me to clarify. My main comparison was to Blackhawks. They relieved a Phrog unit at Al Asad, and started flying three plane divisions to keep up with what two Phrogs were doing. Since 85 percent of the flying was general support, moving people and cargo from A to B, I find that lack of cargo space a serious hinderence. Whats the point of having a higher carrying capacity if you got no room to freakin put anything.
The second part I was indeed referring to Navy MH-60S. At any given time they have 2-3 aircraft undergoing repair for cracking. One aircraft has gone twice in two years.
Phrogs have their downfalls, but they are reliable and have been around long enough that we know where all the kinks are.
Phrogs Phorever
 
Curt22
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RE: Difference Between CH47 Chinook And CH46 S Knight

Tue Sep 09, 2008 11:00 pm



Quoting UH60FtRucker (Reply 7):
And to be fair... the Hawk does have a black eye - the USAF Pave Hawk has an OCRR of 54%. (Hence the argument for a dire need for the new CSAR-X)

Not sure what "OCRR" refers to...never heard that term before, but yes, the USAF HH-60's are getting to be some old horses, put away wet with airframe ages in service from 1981 through 1990's models, and many with more than 7,000 hrs...most of which flown at or near MGW all of their lives with all sorts of bumps and warts that add stress and drag to the airframe, something a "slick" 60 rarely sees.

I wonder how TF 160's MH-60L/K's are standing the test of time in a similar configuration to the HH-60G?

Quoting Dragon6172 (Reply 9):
The second part I was indeed referring to Navy MH-60S. At any given time they have 2-3 aircraft undergoing repair for cracking. One aircraft has gone twice in two years

Wow new MH-60S's already showing airframe cracks? Sure, I've heard of several 308 beams crack and even some gearbox webbing from time to time but these were on the much older USAF HH-60G's spoken of above. Sure is a drag to see new acft having old acft problems.
 
studedave
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RE: Difference Between CH47 Chinook And CH46 S Knight

Wed Sep 10, 2008 6:59 am



Quoting Curt22 (Reply 10):
Wow new MH-60S's already showing airframe cracks?

You're joking, right? This has been on-going since I can't remember when. Most cracked about the time they got around 2000 hours or so on the airframes- some sooner, a few later. There's a fix, but doesn't happen overnight...
Classic planes, Classic trains, and Studebakers~~ what else is there???
 
Curt22
Posts: 334
Joined: Sat Jul 14, 2007 11:43 am

RE: Difference Between CH47 Chinook And CH46 S Knight

Sat Sep 13, 2008 1:39 pm



Quoting Studedave (Reply 11):
You're joking, right? This has been on-going since I can't remember when. Most cracked about the time they got around 2000 hours or so on the airframes- some sooner, a few later.

Nope, not joking...just not engaged on naval rotary wing issues, so surprised to see new acft having these problems. The first 308 beam (and beaded panel) cracks I saw were in the early 90's on acft that were about 10 yrs old (approx 3500 flt hrs). First gearbox webbing cracks came much later...I wonder what SAC did, or didn't do on the MH-60S's that they did on the previous UH/HH-60 airframes to see cracks so much sooner?
 
studedave
Posts: 463
Joined: Sun Oct 15, 2006 4:21 am

RE: Difference Between CH47 Chinook And CH46 S Knight

Sat Sep 13, 2008 3:56 pm



Quoting Curt22 (Reply 12):
I wonder what SAC did, or didn't do on the MH-60S's that they did on the previous UH/HH-60 airframes to see cracks so much sooner?

See post number 8, and other threads where we've talked about this. Number 8 pretty much covers it, though...
Classic planes, Classic trains, and Studebakers~~ what else is there???

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