# Talk:Boeing CH-47 Chinook

WikiProject Military history (Rated C-Class)
C This article has been rated as C-Class on the quality assessment scale.
WikiProject Aviation / Rotorcraft (Rated C-class)
C  This article has been rated as C-Class on the project's quality scale.

## Medium or heavy lift?

The opening line calls it Medium lift but at over twelve metric tonnes is one of the heaviest lifting helicopters produced by the western world and up there with the best of the rest too. should it be called heavy? (sorry i'm not logged in, why does the auto-log expire?) —Preceding unsigned comment added by 121.223.134.247 (talk) 04:37, 2 February 2011 (UTC)

Agree - other articles (e.g. Combat Aviation Brigade, Boeing Chinook (UK variants)) call it H-L. DexDor (talk) 21:13, 31 March 2011 (UTC)
It was originally considered a medium-lift helicopter, but as engine power grew with successive models, so did its lifting capacity, to the point that now it's considered a heavy-lift helicopter. - BilCat (talk) 22:45, 31 March 2011 (UTC)
Airframe is still limited to a MGW, and even though it is the second largest American helicopter I think it's still a medium lift. I think the heavy lifting is really done by Air Force fixed wing in the grand scheme of military doctrine. AMEND: Maybe from a perspective of helicopters only, it is heavy-lift, but frankly I don't know you turn a helicopter from one type into another. --THE FOUNDERS INTENT PRAISE 23:06, 31 March 2011 (UTC)
The Maximum Take-off Weight for the CH-47a is listed as 28,500 lb, while the MTO for the Ch-47D was 50,000 lb. The CH-47A's engines were rated at 2,650 shp, while it was 3,750 shp for the D-model. Those factors should explain the change. - BilCat (talk) 23:26, 31 March 2011 (UTC)
Helicopters are never classed against fixed-wing for airlift. Most countries which have ordered the new models do so because it is considered a heavy lift helicopter. Ng.j (talk) 19:40, 17 April 2011 (UTC)
I would expect most to class it as a Heavy Lift helicopter, but I ran across an Army web site that listed Heavy starting at about 80 Klb max TO weight. I believe User:Akradecki posted that on a helicopter talk page a couple years ago, but I can no longer find the web page. :( -Fnlayson (talk) 21:27, 17 April 2011 (UTC)

## Chinook loss August 2011

I removed the loss of a Chinook in the Iraq and Afghanistan section but it has been restored. Combat losses are not really notable enough for a mention, this is a military aircraft in action it will take losses, sad but true. Suggest it is removed. MilborneOne (talk) 19:23, 6 August 2011 (UTC)

It is a large loss whether it is an accident or downing. A separate article was also created on this event at 2011 ISAF Boeing CH-47 Chinook crash. That's been tagged for articles for deletion. That could be merged here or List of aviation accidents and incidents in the War in Afghanistan, for whatever that's worth... -Fnlayson (talk) 20:06, 6 August 2011 (UTC)

## Question

The Boeing CH-47 Chinook (Mediterranean Alibaba) is an Asian (???) twin-engine, tandem rotor heavy-lift helicopter. Its top speed of 1000 knots (???)

Asian? 1000 knots??? Is this right? Surely not...

76.31.138.55 (talk) 05:08, 8 August 2011 (UTC)JJMartin

The article had been vandalised, should be ok now. MilborneOne (talk) 09:21, 8 August 2011 (UTC)

## Origin of name Chinook

I believe the name "Chinook" refers to the wind of the same name. That wind is named after the tribe described in the article but it makes more since that the helicopter would be named after the wind than the tribe (since helicopters produce a lot of wind). I am not sure so someone should fact check me on this before modifying the article. Sejofgville (talk) 18:50, 12 August 2011 (UTC)

More likely named directly for Chinook people. The Army traditionally uses Native American names for its helicopters. However, a reference for the name's source is needed to say so in the article per WP:VERIFY. -Fnlayson (talk) 18:59, 12 August 2011 (UTC)
I concur with Fnlayson. It doesn't matter what an individual editor 'believes' one way or another, only what official sources have said. Ergo, if you can find a source, a notable individual/company/organisation that records that as fact, it can be included. Personal theory can't be included however, WP:Original Research was built to stop a rogue editor speculating away from the established truth. Likewise, if we cannot find any truth, sources with accounts on some alledged information, we simply do not include that information in the article. Sourcing is harsh, but necessary. Kyteto (talk) 19:43, 12 August 2011 (UTC)

The general policy of naming Army aircraft after Indians tribes, chiefs or terms was made official by authority of AR 70-28, dated 4 April 1969. Although this regulation has been recinded, the Indian names were very popular among Army personnel and the practice continues in place. The commanding general of the US Army Material Command has the responsibility of initiating action to select a popular name for aircraft. For this purpose he has a list of possible names obtained from the Bureau of Indian Affairs (for brevity the names usually consist of only one word). When a new aircraft reaches the production stage or immediately before it goes into production, the commanding general selects five possible names. He bases his selection on the way they sound, their history and their relationship to the mission of the aircraft. They must appeal to the imagination without sacrificing dignity and suggest an aggressive spirit and confidence in the capabilities of the aircraft. They also must suggest mobility, firepower and endurance.

http://www.globalsecurity.org/military/systems/aircraft/mds.htm
(Hohum @) 00:00, 13 August 2011 (UTC)

## Greek Chinook loss in 2007

Changed the "Greek Air Force" to "Greek Army", as Chinooks are not operated by the Hellenic Air Force — Preceding unsigned comment added by 69.242.0.167 (talk) 22:36, 9 April 2012 (UTC)

## September 11 ?

Crashes twice on September 11 in 10 years. Spooky...
Is this information correct? פשוט pashute ♫ (talk) 00:31, 21 August 2012 (UTC)

The numbers of CH-47s transferred from Canada to the Netherlands, as written in the variants section do not add up. First the sentences under the CH-47C section:

Canada bought eight CH-47Cs with deliveries beginning in 1974. These received the Canadian designation "CH-147". One was lost almost immediately while still in the USA, A/C 147001 . It was replaced by another later on at the end of the contract, A/C 47009. They were fitted with a power hoist above the crew door, as well a flight engineer station in the rear cabin and other modifications, a configuration referred to by Boeing as the "Super C". They were often fitted with skis. Two of these machines were lost in crashes, while the others were withdrawn from service in the early 1990s for cost reasons and were sold to the Netherlands.

Now the sentences under the CH-47D section:

The Netherlands acquired all seven of the Canadian Forces' surviving CH-147s and upgraded them to CH-47D standards. Six more new-build CH-47Ds were delivered in 1995 for a total of 13.

The number of Chinooks sold to the Netherlands according to the CH-47C section is 6 (8 - 2 = 6, or more specifically 8 - 1 + 1 - 2 = 6).
The number of Chinooks acquired by the Netherlands according to the CH-47D section is 7.

So either someone made a typo, or we have a mysteriously appearing aircraft. -Noha307 (talk) 20:27, 26 March 2013 (UTC)

The dutch acquired seven former Canadian helicopters D-661 to D667 which were 147003 to 147009, of the original Canadian a/c 147002 was w/o in 1982, the "two" lost also refers to 147001 which officially was never Canadian. I have tweaked the CH-47C text. MilborneOne (talk) 20:49, 26 March 2013 (UTC)

## Specs correct?

Under specs, it lists "Disc area: 5,600 ft2 (2,800 ft2 per rotor disc) (260 m2)". I'm wondering if this is correct as the rotors overlap. I have removed it until the correct area size can be confirmed. - thewolfchild 16:52, 16 July 2013 (UTC)

I restored the full areas. There was no reason to remove all that, imo. Jane's Helicopter Markets and Systems lists 5,655 ft2 as the total disc area for the pair. -Fnlayson (talk) 17:14, 16 July 2013 (UTC)
Yes, well, the only ref to Jane's on the page is a dead link. I did refer to the Boeing ref [1], which states that even though each rotor is 60 ft. in diameter, because they overlap, the overall length is only 99 ft. I had calculated using that (incorrectly) as a diameter, coming up with an area 7,854 ft. (I was about to correct that, but...)
Anyway, the point still stands that as they overlap, simply adding the two together as you have does not give a true value of the overall area covered by the rotors. So I stand by my original deletion and request that a correct area first be determined before being added to the article specs. (btw- aren't you an engineer? Surely you can figure what the actual area is...) - thewolfchild 18:45, 16 July 2013 (UTC)
Excuse my ignorance but how does that fact that the overlap reduce the area of either, the disc area still stays the same. MilborneOne (talk) 19:00, 16 July 2013 (UTC)
Overlapping does not reduce the area of either rotor, but it does reduce the overall area of the two combined. You can't simply add the two together. Each rotor has a diameter of 60 ft. If you add those two lengths together, you get 120 ft. But, as they overlap, the length is only 99 ft. Over 20 ft. is lost in just the length of the two alone, due to the overlap. Therefore, to provide a correct overall area of the two, what is lost in sq. ft. due to overlap should be calculated as well. I will be the first to say that I don't know how to calculate that right now. (I even made a mistake already) But, the correct calculation should be made first. - thewolfchild 19:16, 16 July 2013 (UTC)
OK but we dont do calculation, we need to go by what reliable sources say (and do), do you have a reliable source that measures area of a Chinook less overlap? MilborneOne (talk) 19:21, 16 July 2013 (UTC)
• OK, the correct area for 2 rotors without overlap is 5,655 ft2. Calculating the total area with overlap is more than just simple math so this gets into Original Research. -Fnlayson (talk) 19:25, 16 July 2013 (UTC)
User:Dave1185, is your CAPS BUTTON stuck? - thewolfchild 21:57, 16 July 2013 (UTC)
Geez, everyone... relax. I've already stated I made an error in trying to calculate it myself. I asked here, on the talk page, if anyone knows how to calculate it. I also said that the value entered into the specs should be correct. Right now it isn't. Just because you don't care for how I've tried to point that out, doesn't mean it should remain incorrect.
Yes, what is ultimately entered into the "Disc Area" field should be supported by a cite, but it should also be correct. So aside from my original request, I will ask if anyone (including any aviation or research experts here) knows of a citable source that states the correct disc area for the CH-47, with the overlap. In the meantime, are you all gonna insist it remain incorrect? Why? Just to blather away about possible infractions of the wiki-rules? How about WP:IAP and WP:BURO? - thewolfchild 19:56, 16 July 2013 (UTC)
Hi User:Thewolfchild! It is actually not very difficult to calculate the area. But to cite a number calculate by you (or me!) here would be "original research " (you may be sick of every one using this term ;) ) WP:NOR does say that simple counting can always be done, but I guess this calculation would not fall under that. Just to satisfy your academic interest, you can go here. The calculation here may be simpler due to the two rotors being identical. Thanks! Anir1uph | talk | contrib 20:05, 16 July 2013 (UTC)
Hi Anir. I appreciate the reply and the help, but if you read my last post, I did say that the correct value, if/when found, should be cited when added. Thanks - thewolfchild 20:28, 16 July 2013 (UTC)

────────────────────────────────────────────────────────────────────────────────────────────────────

The disk area of a helicopter is not the same as the footprint of the rotor system (although for most helicopter configurations they are equal)--the disk area is part of the calculations for the disk loading, which is a property of each rotor, not the rotor system as a whole. In the overlap area, the mass flow through the rotor system is higher than the other locations on the aircraft (source), so you can effectively double-count that area when calculating total disk area. The original page was correct, the total disk area should be 5,655 ft^2. Mildly MadTC 20:54, 16 July 2013 (UTC)

Well, this seems even more complicated than before. The distinction you've made (load vs. area) is not apparent on the main page. But, just the same, so I'm clear on this... the 'disc area' is not the same as the 'overall area' covered by a rotor?
And, in the article you ref'd as a source, it only mentions that "The maximum velocity occurs only in the zone below where the counter-rotating blades overlap...". I couldn't find where it says that increase in load exactly equals the decrease of area providing load, or where you've claimed one "can effectively double-count that area when calculating total disk area." If the area of overlap = X, then how is it that load of that area = X x 2?
Guys, I'm not trying to be a pain-in-the-ass here. I just want the specs to be correct. - thewolfchild 21:49, 16 July 2013 (UTC)
It's a little difficult to explain, sorry. This is all because there's two rotors acting in the overlap section. The source I provided mentions that the downwash velocity in the overlap is greater, therefore, more force in that section of the rotor system. There's some second-order aerodynamic effects that make it not exactly twice the lift, but that's the gist of it.
Maybe this analogy will make more sense: in a fixed-wing aircraft, the formula for lift is (Lift Force) = 1/2 * (Air Density) * (Velocity)^2 * (Coefficient of Lift) * (Wing Area). The analogous equation for helicopters is (Thrust force) = 1/2 * (Air Density) * (Rotor tip speed)^2 * (Coefficient of Thrust) * (Disk Area). Note that (Wing Area) and (Disk Area) play a similar role in each equation. So, think of the Chinook as sort of a "helicopter biplane": even though the wings (rotors) overlap when viewed from above (i.e. the "footprint"), you still need to count the full area of both wings in the calculation of the force you get. This is the reason we should just add the rotor disc areas together. FWIW, I think the note on the original version of the page was adequate to make this distinction clear to someone who is familiar with helicopter physics. Mildly MadTC 22:53, 16 July 2013 (UTC)

### Compromise?

By the way, the original edit stated: Disc area: 5,600 ft2 (2,800 ft2 per rotor disc) (260 m2).
Now it only states: Disc area: 5,600 ft2 (260 m2).
For the time being, it should be the other way around, and state: Disc area: 2,800 ft2 per rotor disc
- thewolfchild 22:05, 16 July 2013 (UTC)
Not unless that figure is given in the cited sources. The Frawley source given in the ref section for the specs only gives the figures for area of both disks. Anything else would stray into OR again. BilCat (talk) 22:22, 16 July 2013 (UTC)
Bil, if you noticed, I was only suggesting what was already in the original edit, before I came along today.
On another note, I see that many of the listed specs are linked with definitions and/or explanations of what they are. Could "Disc area" have this done as well? - thewolfchild 22:51, 16 July 2013 (UTC)
Some helicopters have contrarotating blades on the same axis, like the Kamov Ka-27. Perhaps you could see if they care about their total overlap for this specification? (Hohum @) 14:05, 17 July 2013 (UTC)
Bah, seems like no one cares so, why bother? I thought all the articles on WP were for everyone, but apparently some pages are just for aviation engineers. - thewolfchild 20:26, 18 July 2013 (UTC)

## Weights?

• Loaded weight: 26,680 lb (12,100 kg)
• Max. takeoff weight: 50,000 lb (22,680 kg)

How can it takeoff at almost double it's maximum loaded weight? These terms need to be defined/explained somewhere. Does the Max loaded weight refer only to "in the cabin" loads? Is there a separate (unmentioned) sling load limit? Does it really make a difference if the load in the back or dangling below? Gravity sucks equally hard at both locations. Roger (Dodger67) (talk) 11:49, 18 July 2013 (UTC)

Loaded weight is basically the weight of the helicopter without fuel and cargo. Then, you add cargo (either in the slings or in the cabin) and fuel to get up to 50,000 lbs. Mildly MadTC 13:28, 18 July 2013 (UTC)

## B-Class or C-Class?

On the article page it says this is a C-class article, but on the Talk page it is rated B-Class by WikiProject Military History and WikiProject Aviation / Rotorcraft. Should the note on the article page be changed? By the way, I found the article to be well-written and informative - nice job y'all. :o) Mark D Worthen PsyD 08:15, 26 August 2013 (UTC)

I don't believe this article is referenced well enough to be 'suitably referenced' per the B-class checklist. There are a couple cite needed tags and some unreferenced paragraphs and entries. It's roughly a C+ with not too far from making B-class. -Fnlayson (talk) 18:02, 26 August 2013 (UTC)

## Blacklisted Links Found on the Main Page

Cyberbot II has detected that page contains external links that have either been globally or locally blacklisted. Links tend to be blacklisted because they have a history of being spammed, or are highly innappropriate for Wikipedia. This, however, doesn't necessaryily mean it's spam, or not a good link. If the link is a good link, you may wish to request whitelisting by going to the request page for whitelisting. If you feel the link being caught by the blacklist is a false positive, or no longer needed on the blacklist, you may request the regex be removed or altered at the blacklist request page. If the link is blacklisted globally and you feel the above applies you may request to whitelist it using the before mentioned request page, or request its removal, or alteration, at the request page on meta. When requesting whitelisting, be sure to supply the link to be whitelisted and wrap the link in nowiki tags. The whitelisting process can take its time so once a request has been filled out, you may set the invisible parameter on the tag to true. Please be aware that the bot will replace removed tags, and will remove misplaced tags regularly.

Below is a list of links that were found on the main page:

• http://www.army-technology.com/projects/chinook/
Triggered by \barmy-technology\.com\b on the local blacklist

From your friendly hard working bot.—cyberbot II NotifyOnline 10:21, 3 April 2014 (UTC)

## CH-47 rescued in Afghanistan by Russian Mi-26

In 2002, a Russian Mi-26 heay-lift helicopter rendered assistance to the United States Army. The Mi-26 recovered a downed CH-47 ‘Chinook’, the heaviest rotary wing aircraft in U.S. Army Aviation, nicknamed the ‘flying wagon,’ from an inaccessible location in Afghanistan and transported it to the American base at Bagram. None of America’s production heavy transport helicopters could match the capabilities of the Mi-26, which is able to lift 20 metric tons into the skies, whereas the CH-47D/F medium-lift helicopter models of the USAF only manage to lift up to 12.7 metric tons. This makes the USAF's capabilities in terms of vertical lifting grossly inferior to the Russian army and other armies which employ the Russian-made Mi-26. -- Alexey Topol (talk) 05:38, 26 May 2014 (UTC)