# C-17 Globemaster III



## Amsel (Nov 23, 2008)

This particular aircraft is fascinating to me. Is anyone else a fan of it?

"The C-17 measures approximately 174 feet (53 meters) long with a wingspan of 169 feet, 10 inches (51.76 meters). The aircraft is powered by four fully reversible Pratt Whitney F117-PW-100 engines (the commercial version is currently used on the Boeing 757). Each engine is rated at 40,440 pounds of thrust. The thrust reversers direct the flow of air upward and forward to avoid ingestion of dust and debris. Maximum use has been made of off-the-shelf and commercial equipment, including Air Force-standardized avionics. 

The aircraft is operated by a crew of three (pilot, copilot and loadmaster), reducing manpower requirement risk exposure, and long-term operating costs. Cargo is loaded onto the C-17 through a large aft door that accommodates military vehicles and palletized cargo. The C-17 can carry virtually all of the Army's air-transportable equipment. 

Maximum payload capacity of the C-17 is 170,900 pounds (77,519 kilograms), and its maximum gross takeoff weight is 585,000 pounds (265,352 kilograms). With a payload of 160,000 pounds (72,575 kilograms) and an initial cruise altitude of 28,000 feet (8,534 meters), the C-17 has an unrefueled range of approximately 2,400 nautical miles. Its cruise speed is approximately 450 knots (.74 Mach). The C-17 is designed to airdrop both equipment and 102 paratroopers".


----------



## evangilder (Nov 23, 2008)

Oh hell YEAH! I have seen several demos of the C-17 over the last few years and it never fails to impress me with it's nimbleness despite it's size. It's been extremely reliable. I think the C-17 will go down in history as being one of the greats with the C-130 and C-47.


----------



## Amsel (Nov 23, 2008)

It is amazing to see that big bird land. With its reverse thrust engines it can land almost anywhere. Very nimble for its size.


----------



## DerAdlerIstGelandet (Nov 23, 2008)

Great aircraft. Got to fly on one onetime. It really is an amazing aircraft in my opinion, when it comes to capabilities.


----------



## HoHun (Nov 23, 2008)

Hi Amsel,

>Is anyone else a fan of it?

It's not pretty, but the way it flies is just amazing ...

Regards,

Henning (HoHun)


----------



## DerAdlerIstGelandet (Nov 23, 2008)

I think for a cargo aircraft, she is pretty damn good looking.

I like that pic with the Ju 52 and the C-117. Was that taken at the ILA in Berlin?


----------



## CharlesBronson (Nov 23, 2008)

Is this picture real or photoshopped ?

If true is a really amazing climb


----------



## Crunch (Nov 23, 2008)

Looks real to me!

I first saw one of these at Avalon Airshow in about 96, before I had even heard of them! Very impressive aircraft. And as DerAdlerIstGelandet said, for a bus, it looks damn fine!


----------



## Wildcat (Nov 23, 2008)

It certainly is an impressive aircraft. Here are some pics I snapped of an RAAF version.


----------



## comiso90 (Nov 23, 2008)

Made in my hometown of long beach,ca.... you cant imaging the agility until u see it in flight.


----------



## evangilder (Nov 23, 2008)

CharlesBronson said:


> Is this picture real or photoshopped ?
> 
> If true is a really amazing climb



I was there watching it through my viewfinder. It was not photoshopped. That is how it came out of the camera, and how the C-17 came out of the dust. Very, very impressive aircraft.


----------



## Airframes (Nov 23, 2008)

Thought they must be your pics Eric! Great as usual!
Those from Wildcat are the first to give me an impression of its sheer size - b****y massive! Only ever seen one once, at a distance, going into Brize Norton, looked big then, but nothing to scale it against. Now I know!
Thanks for all the pics guys.
Terry.


----------



## Flyboy2 (Nov 23, 2008)

Love that one... A few days ago there were three C-17's flying in a close line formation low over my school. Made one heck of a racket. Kinda felt stupid thought because I was the only one looking up at it....


----------



## davparlr (Nov 23, 2008)

Unless they upgraded to flat panels, the C-17 uses the same 6x6 inch color CRTs I was responsible for developing for the B-2. One of the guys who worked for me left and went to work on the C-17 control and display avionics. There is an interesting story about those CRTs. Due to national security, all B-2 components were required to be manufactured in the U.S. (this later changed to allow equipment that could possibly be built here if sources were cut off), so, my team went searching for domestic high resolution color CRTs. Well, at first we could find no manufactures that built CRTs in the U.S., not Magnavox, not RCA, not Motorola, no one. Finally we did find one manufacturer, Techtronix, an electronic test equipment manufacturer. Not only were they the only manufacturer in the U.S., but, to our happy surprise, they also happened to build the brightess, highest resolution display in the world, almost fifty percent higher than the resolution of the best high resolution computer monitor at the time. Getting this strickly commercial supplier to sell to the government and accept all the associated red tape is another story, including the pressuring and pleading by some very high government officials, and a lot of money. They later sold the manufacturing rights to another company, probably to get away from that red tape.

As for the C-17, it is a young upstart with great talent that, in my mind and heart, has a lot of wars to go through and worldwide emergencies to support before it can match the greatness of the plane it replaced, the C-141.


----------



## Trebor (Nov 24, 2008)

I think I'll build a model of this beautiful bird, if there is one


----------



## Crunch (Nov 24, 2008)

Trebor said:


> I think I'll build a model of this beautiful bird, if there is one



in 1:24 scale?


----------



## evangilder (Nov 24, 2008)

davparlr said:


> Unless they upgraded to flat panels, the C-17 uses the same 6x6 inch color CRTs I was responsible for developing for the B-2. One of the guys who worked for me left and went to work on the C-17 control and display avionics. There is an interesting story about those CRTs. Due to national security, all B-2 components were required to be manufactured in the U.S. (this later changed to allow equipment that could possibly be built here if sources were cut off), so, my team went searching for domestic high resolution color CRTs. Well, at first we could find no manufactures that built CRTs in the U.S., not Magnavox, not RCA, not Motorola, no one. Finally we did find one manufacturer, Techtronix, an electronic test equipment manufacturer. Not only were they the only manufacturer in the U.S., but, to our happy surprise, they also happened to build the brightess, highest resolution display in the world, almost fifty percent higher than the resolution of the best high resolution computer monitor at the time. Getting this strickly commercial supplier to sell to the government and accept all the associated red tape is another story, including the pressuring and pleading by some very high government officials, and a lot of money. They later sold the manufacturing rights to another company, probably to get away from that red tape.
> 
> As for the C-17, it is a young upstart with great talent that, in my mind and heart, has a lot of wars to go through and worldwide emergencies to support before it can match the greatness of the plane it replaced, the C-141.



I'm not familiar with the differences in the glass panels, but here is the C-17 that was at the 2007 Riverside show.






I think the C-17 will go down as one of the greats. The amount of hours it has flown so far are impressive (over a million hours of operational missions). In 2006, it set the record for the heaviest load dropped out of any aircraft, with a 65,000 lbs. simulated AirLaunch QuickReachTM rocket. It has been performing at 84.7 percent mission-capable rate when tasked for missions, which is pretty impressive.


----------



## davparlr (Nov 24, 2008)

evangilder said:


> I'm not familiar with the differences in the glass panels, but here is the C-17 that was at the 2007 Riverside show.



I cannot tell if they are CRTs, although they look like they are. Here is the displays in the B-2. This is a simulator picture.



> I think the C-17 will go down as one of the greats.



I have no doubt it will.


----------



## Trebor (Nov 24, 2008)

Crunch said:


> in 1:24 scale?



LOL no

I did just find one by Revell Germany in 1/144 scale.

how big is that?


----------



## DerAdlerIstGelandet (Nov 24, 2008)

Will someone ask Ho Hun if that picture he posted with the Ju 52 and the C-17 is from the ILA in Berlin. I think he still has me on ignore...

I really like that pic.


----------



## Matt308 (Nov 24, 2008)

I sound like a broken record, but saw the C-17 at the local McChord AFB doing a short takeoff and landing demonstration. I can't impress upon you how amazing the performance of this aircraft is. It almost looks like it defies physics.


_View: https://www.youtube.com/watch?v=RYxcZZmBN08_


_View: https://www.youtube.com/watch?v=N2awzBWwr3Y_

The airplane is deceiving. The fuselage is so big, that the airplane looks small. As if it has little stubby wings. We are talking 53m length and 52m wingspan. And she weighs about 280,000lbs empty! No puny airplane here.


----------



## CharlesBronson (Nov 24, 2008)

> I was there watching it through my viewfinder. It was not photoshopped. That is how it came out of the camera, and how the C-17 came out of the dust. Very, very impressive aircraft.



Thank you, there are some serious power in that engines.


----------



## Flyboy2 (Nov 24, 2008)

Nice video's... The performance specifications on such a large aircraft such as this are staggering


----------



## DerAdlerIstGelandet (Nov 25, 2008)

Did anyone ask Ho Hun for me?


----------



## Matt308 (Nov 25, 2008)

I'll do it, Adler.


----------



## DerAdlerIstGelandet (Nov 25, 2008)

Thanks, like I said, I think he has me on ignore still from our little spat last year...


----------



## ccheese (Nov 25, 2008)

They fly that big sucker with a stick ? I expected the typical column/wheel
routine. Hmmmm pilot flies left handed... that ought to be different !
It still an impressive aircraft.....

Charles


----------



## Matt308 (Nov 25, 2008)

I've always wondered that Mr. C. Airbus A320/330/340/350/380 aircraft are all stick driven. #1 position is on the left side. #2 is on the right. Now cockpit pilot/co-pilot allows for both to exchange 'pilot-in-command' during a given flight. And this is not uncommon.

Boeing aircraft have control columns. This affords either pilot a common airplane human-machine interface (HMI).

As part of Operator training curriculum it is common for pilots to develop skills in the right seat in preparation for assuming left seat responsibilities. With HMI controls reversed depending upon pilot/co-pilot position, I have always wondered how that affected training, crew resource management, and pilot skill.

I know that I am MUCH less skillful in hand-eye coordination with my left hand.

I can't imagine being a copilot operating flight control surfaces with my right hand and throttles with my left... and then having to transition to the pilot position and operating the flight control surfaces with my left hand and the throttles with my right.

Training is key. But righties and lefties will always retain an inherent difference in human factors. And personally, I believe this to be statistically dangerous.


----------



## Amsel (Nov 26, 2008)

This aircraft defies your eyes when you see it fly. I love how it would be able to land in a clearing, back up, unload and take off in a matter of a minute from a very small area.


----------



## Trebor (Nov 26, 2008)

how small an area? like a 5,000 foot runway? cos I don't think it could take off like that. the airport near me has only one runway, and it's 5,000 X 150


----------



## Amsel (Nov 26, 2008)

Boeing claims that “With a payload of 160,000 pounds, the Boeing C-17 can take-off from a 7,600 foot airfield, fly 2,400 nautical miles, and land on a small austere field of 3000 feet or less”

It claims to be able to land in 914 meters, although at what weight, and under which landing definition of landing distance that number corresponds to is a mystery.

I also read somewhere that it has a “tactical landing distance” of 1066 meters. Again, I don’t know at what weight and what that term means exactly.


----------



## Amsel (Nov 26, 2008)

> The C-17's ability to fly long distances and land in remote airfields in rough, land-locked regions make it a premier transporter for military, humanitarian and peacekeeping missions. It can:
> 
> Take off from a 7,600-ft. airfield, carry a payload of 160,000 pounds, fly 2,400 nautical miles, refuel while in flight and land in 3,000 ft. or less on a small unpaved or paved airfield in day or night.
> Carry a cargo of wheeled U.S. Army vehicles in two side-by-side rows, including the U.S. Army's main battle tank, the M-1. Three Bradley infantry-fighting vehicles comprise one load.
> ...



Boeing: Integrated Defense Systems - C-17 Globemaster III - C-17 Globemaster III Home


----------



## Trebor (Nov 26, 2008)

I guess the only way to know for sure is to test it! LOL


----------



## Matt308 (Nov 26, 2008)

5000ft? Try less than 3500ft.


----------



## Trebor (Nov 26, 2008)

what do you mean, matt? the airport Manager at the Chehalis/Centralia airport told me that the runway's length is exactly 5,000 X 150


----------



## HoHun (Nov 26, 2008)

Hi Charles,

>Hmmmm pilot flies left handed... that ought to be different !

Actually, his stick grip is of the HOTAS type that can't really be flown with the left hand because you'd have a big button right beneath your palm.

Coupled with the observation that the visible throttles are on the far right side of the centreline pillar, I'd say the pilot flies right-handed too and has another set of throttles on his left just out of view behind the seatback in the cockpit shot.

There are other, sidestick-controlled types however where the pilot definitely flies left-handed, so it seems it's not considered a serious obstacle. Personally I think one's 'strong' hand offers a lot more precision normally - however, it's also true that training can do amazing things for you ...

Regards,

Henning (HoHun)


----------



## HoHun (Nov 26, 2008)

Hi Adler,

>Will someone ask Ho Hun if that picture he posted with the Ju 52 and the C-17 is from the ILA in Berlin. 

Yes, it is - taken in 2002. 

I was actually looking for some nice shots of a C-47 taxying in front of a C-17 at an earlier ILA, but those rolls haven't been digitized so I didn't find them yet. Guess it must have been 2000 or even earlier.

While searching, the shot with the Ju 52 caught my eye, and I liked it well enough to post it here. I'm glad you appreciate it despite the small apparent size of the Ju 52! 

>I think he still has me on ignore...

No longer, my friend! 

Regards,

Henning (HoHun)


----------



## DerAdlerIstGelandet (Nov 26, 2008)

HoHun said:


> Hi Adler,
> 
> >Will someone ask Ho Hun if that picture he posted with the Ju 52 and the C-17 is from the ILA in Berlin.
> 
> ...



Very nice pic. I love the Ju 52 flying behind the C-17.


----------



## HoHun (Nov 26, 2008)

Hi again,

>>Hmmmm pilot flies left handed... that ought to be different !

>Actually, his stick grip is of the HOTAS type that can't really be flown with the left hand because you'd have a big button right beneath your palm.

Wait - I screwed up there, I was looking at the bottom picture and not at the top picture that has the exact mirror image of the big button and would obviously require the pilot to fly left-handed just as you say!

Regards,

Henning (HoHun)


----------



## Matt308 (Nov 27, 2008)

Trebor said:


> what do you mean, matt? the airport Manager at the Chehalis/Centralia airport told me that the runway's length is exactly 5,000 X 150



Sorry Trebor. I thought you were asking if 5000ft is enough for the C17. The C17 STOL capability only requires 3500ft. That's what I meant. Now keep in mind that is not the amount of pavement that is required. That would quite a bit less. Rather that is the amount of run required to clear a vertical obstacle at the end of the run. The height of the vertical obstacle, I can't recall.

FlyboyJ might know.


----------



## Trebor (Nov 27, 2008)

ohhh, I see. hehe I misunderstood ^^'


----------



## Burmese Bandit (Dec 7, 2008)

I know that the C-130 has sucessfully been tested for a carrier landing and takeoff. Could a C-17, perhaps at light weights, do the same? Is it totally impossible, 'possible but the pilot had better write his will first' or just possible?


----------



## Matt308 (Dec 7, 2008)

I don't think the carrier deck is rated for such weights. And the island would get in the way of the 170ft+ wingspan.

I would say possible. Once.


----------



## Burmese Bandit (Dec 8, 2008)

So clip the wings! Or build bigger carriers...


----------



## Trebor (Dec 8, 2008)

Matt308 said:


> I don't think the carrier deck is rated for such weights. And the island would get in the way of the 170ft+ wingspan.
> 
> I would say possible. Once.



heh, yea. and that once would bee a 99.9% chance made of fail. XD besides, I don't think that even with the carrier being full into the wind, and the plane hooked up to the catapult, that sucker could get airborne


----------



## HoHun (Dec 8, 2008)

Hi Matt,

>I don't think the carrier deck is rated for such weights. And the island would get in the way of the 170ft+ wingspan.

Here is a screenshot from my favourite simulator, X-Plane ...

The C-17 is not parked there, it's in the middle of a bolter.

Without arresting gear, it won't stop even at minimum weight. Retro-fitted with arresting gear, it is tricky to find the correct angle-of-incidence for a trap. I'd have to retro-fit an AoA indexer, but this still would leave the question of the correct AoA. I've managed a couple of bolters so far - and a couple of ramp strikes, I'm afraid. Somehow, the cockpit has to overfly the #4 wire at considerable height to place the main wheels safely on the deck ... takes some getting used to! 

Regards,

Henning (HoHun)


----------



## Matt308 (Dec 8, 2008)

HoHun, your pic doesn't leave much margin for error. 

Even with an angled deck, you are only talking about 25ft on either side to the edge of the deck. Add in some other objects, like the island, equipment, and aircraft. Not sure if it's gonna be possible.

And just because you are accomplishing touch and goes on a simulator, I still say the deck won't hold up. But fun information nonetheless.


----------



## FLYBOYJ (Dec 8, 2008)

Also consider that if a C-17 was fitted with a hook, upon landing it would have to throttle up - SOP on carrier landings. If you find a practical cable to make this work, I doubt it would contain the aircraft after landing.

Either way I think the aircraft would wind up 2 decks lower when it came to a stop!


----------



## SoD Stitch (Dec 8, 2008)

Burmese Bandit said:


> So clip the wings! Or build bigger carriers...



You _might_ be able to launch a C-17 from the newest _Nimitz_-class carrier, the _Gerald R. Ford_ (which actually hasn't even been laid down yet), as the island is much further back than on the standard _Nimitz_-class carriers.


----------



## HoHun (Dec 8, 2008)

Hi Matt,

>Even with an angled deck, you are only talking about 25ft on either side to the edge of the deck. Add in some other objects, like the island, equipment, and aircraft. Not sure if it's gonna be possible.

In the picture above, the wing tip would have struck the two E-2C aircraft parked there - fortunately, they're not "hard" objects in the simulator. (They can't be re-spotted in the sim.)

>And just because you are accomplishing touch and goes on a simulator, I still say the deck won't hold up.

Absolutely correct  There is a simulator that does take material strengths into account too, but I haven't tried that one yet. Tends to use a lot of computing power, and my 6-year-old box just doesn't have it.

Rigs of Rods

Still worth a look for all lovers of fine machinery 

Regards,

Henning (HoHun)


----------



## HoHun (Dec 8, 2008)

Hi Flyboyj,

>Also consider that if a C-17 was fitted with a hook, upon landing it would have to throttle up - SOP on carrier landings. If you find a practical cable to make this work, I doubt it would contain the aircraft after landing.

Hm, I think a cable that wouldn't break upon arresting 275000 lbs would probably hold an aircraft with "just" 160000 lbs of thrust easily.

You're right with regard to the standard procedure ... but on the other hand the C-17 at minimum weight will fly at a surprisingly low speeds, so you can still throttle up if there is no deceleration.

I think it might even be possible to fly off the carrier deck without catapulting the C-17, but the simulator insists on putting the plane on the catapult if I select a carrier start. I'd have to land first, then taxi into a position aft of the catapult to try an unassisted start. (Which reminds me ... does the C-17 do JATO? 

>Either way I think the aircraft would wind up 2 decks lower when it came to a stop!

Quite likely!

Regards,

Henning (HoHun)


----------



## FLYBOYJ (Dec 8, 2008)

HoHun said:


> I think a cable that wouldn't break upon arresting 275000 lbs would probably hold an aircraft with "just" 160000 lbs of thrust easily.


Actually the normal tinsel strength is 215,000 lbs. You'd have to consider the 160,000 pounds of thrust plus the kinetic energy of the aircraft as it lands and catches the cable. My guess you're going to see over 215K on the cable.


----------



## beaupower32 (Dec 8, 2008)

The thrust reverser system on this airplane is garbage. We have done so many T/R Rigs, changing actuators, prox sensor adjustments, and blocker door rod changes. They should get rid of the core reverser and make it like a normal civilian with just the fan. But no. Air Force had to be different. Anyways, hate to ramble. Im a C-17 Jet Engine Mechanic stationed at Charleston AFB, South Carolina. Been here 2 years and cant wait to leave.


----------



## HoHun (Dec 8, 2008)

Hi Flyboyj,

>Actually the normal tinsel strength is 215,000 lbs. You'd have to consider the 160,000 pounds of thrust plus the kinetic energy of the aircraft as it lands and catches the cable. My guess you're going to see over 215K on the cable.

The good news is, I just managed to accomplish a trap with C-17 

The bad news is, I didn't think of checking the G factor of the deceleration - which would have been easy as the simulator has a pretty comprehensive "telemetry" function. I will have to give it another go tomorrow.

Anyway, here a screenshot of the trap. I added an AoA indexer and set desired AoA to 15 degrees, using 32 degrees of flaps to achieve the correct (as it turned out) touch-down angle. Unfortunately, the actual functional hook geometry is invisible in X-Plane, requiring some guesswork with a plane of the size of the C-17.

(Increasing the horizontal viewing angle from 50 degree to 80 degree proved the key to avoiding ramp strikes ... it's all about the sight picture, I guess. No peripheral vision, no depth perception in the simulator.)

Regards,

Henning (HoHun)


----------



## Matt308 (Dec 8, 2008)

HoHun, you are not serious in your analysis are you. You/re just yanking our chains right. You surely are not basing a position on a PC game simulator. Please tell me so.


----------



## HoHun (Dec 9, 2008)

Hi Matt,

>HoHun, you are not serious in your analysis are you. You/re just yanking our chains right. You surely are not basing a position on a PC game simulator. Please tell me so.

Hm, which position? The question whether the arrestor wire would be overstressed? I'm pretty sure X-Plane will show a realistic deceleration, but I'm just as sure that this will only yield the "best case" tensile stress on the cable - in real life, the cable will be stressed quite a bit more in off-centre landings, and I don't expect the simulator to take this into account.

I could also calculate the "best case" deceleration on the back of an envelope, but it's more fun to fly a trap in the simulator and look at the data readout afterwards. You can actually check the time history to find out what kind of deceleration characteristic the simulator is using.

(Don't underestimate X-Plane though - it has been used by, and praised by, quite a few aircraft designers. The key is that to learn something from a simulator, you have to be aware of its limitations.)

Regards,

Henning (HoHun)


----------



## Matt308 (Dec 9, 2008)

HoHun, I was hoping you would take the subtle out.  Have you ever taken an engineering strength of materials class? Assuming not, I am a bit incredulous that you would base a technical position on a game. I have better confidence in you than that, buddy.

I remember my professor actually teaching us about the catapult launch forces. For those who do not know, the airplane is attached to the shuttle with a known tensile strength length of stock metal. At the end of the shuttles run, the airplane momentum carries it past the shuttle c0ck. With a huge "bang", the metal connection is actually broken, or snapped in half. I know. I actually examined one as part of my engineering curriculum.

The weight of the airplane actually determines the diameter of the shuttle connection. The knowledge of the connection metalurgy and its diameter determines the absolute strength of the material.

I don't recall the problems that we worked in the mid 80's, but I want to say that the absolute tensile strenght to launch an aircraft in the A-6/F-14 range was already in the 200,000+ lbs/sqin range.

Now compound that with an aircraft that is MGW of close to 600,000lbs and you are talking a completely different animal. Launch is impossible. And even landing with hydraulic compensation to minimize wire tensile stress (even with minimal cargo) is going to result in stresses that cannot be supported by the arrestor gear.

And this is not even contemplating the deck forces. In all likelihood, a C-17 landing on a carrier would not only destroy the arrestor gear, but also damage the decking to the point of being catastrophic due to both massive tensile an compressive forces.


----------



## beaupower32 (Dec 9, 2008)

Matt308 said:


> HoHun, I was hoping you would take the subtle out.  Have you ever taken an engineering strength of materials class? Assuming not, I am a bit incredulous that you would base a technical position on a game. I have better confidence in you than that, buddy.
> 
> I remember my professor actually teaching us about the catapult launch forces. For those who do not know, the airplane is attached to the shuttle with a known tensile strength length of stock metal. At the end of the shuttles run, the airplane momentum carries it past the shuttle c0ck. With a huge "bang", the metal connection is actually broken, or snapped in half. I know. I actually examined one as part of my engineering curriculum.
> 
> ...


----------



## Burmese Bandit (Dec 10, 2008)

Looks like I started quite a discussion there guys!


----------



## HoHun (Dec 10, 2008)

Hi Matt,

>Assuming not, I am a bit incredulous that you would base a technical position on a game. I have better confidence in you than that, buddy.

How about you try and sum up my "technical position" so that I can tell you that you got me completely wrong in order to restore your confidence?

I won't even comment on the rest of your post because I see no connection to anything I wrote here.

Regards,

Henning (HoHun)


----------



## SoD Stitch (Dec 10, 2008)

Matt308 said:


> I remember my professor actually teaching us about the catapult launch forces. For those who do not know, the airplane is attached to the shuttle with a known tensile strength length of stock metal. At the end of the shuttles run, the airplane momentum carries it past the shuttle c0ck. With a huge "bang", the metal connection is actually broken, or snapped in half. I know. I actually examined one as part of my engineering curriculum.



As I recall, there are all different sizes of the "hold-back" bolt, depending on the launch weight of the a/c. 

And, actually, the bolt just holds the a/c back from the impetus of the catapult shuttle trying to launch the a/c; as soon as the "pull" from the catapult shuttle exceeds the design strength of the hold-back bolt, it snaps and releases the a/c for launch.


----------



## Matt308 (Dec 10, 2008)

HoHun said:


> Hi Matt,
> 
> >Assuming not, I am a bit incredulous that you would base a technical position on a game. I have better confidence in you than that, buddy.
> 
> ...



Henning this isn't personal, buddy. Please don't go there.

I am only carrying on a dialogue that became technical. I provided a technical explanation for my position. It wasn't meant as a personal attack.

I can't sum up your technical position. I have no idea what that is. You have only cited playing a game on a PC of which you have not indicated you have any contributions to the software application's origin. Do you have the high level software development requirements that model the aircraft carrier deck structural loads, the shuttle kinematics and the strength of materials used for the launch modeling? I think not. I can't believe that a PC game would contain such level of detail, as this would make the game so costly as to be virtually out of reach to anyone except gov't entities.

Settle down. This isn't a pissing match. All is well.


----------



## Matt308 (Dec 10, 2008)

SoD Stitch said:


> As I recall, there are all different sizes of the "hold-back" bolt, depending on the launch weight of the a/c.
> 
> And, actually, the bolt just holds the a/c back from the impetus of the catapult shuttle trying to launch the a/c; as soon as the "pull" from the catapult shuttle exceeds the design strength of the hold-back bolt, it snaps and releases the a/c for launch.



You are right SoD. Here's a good explanation I found.

The purpose of the holdback is to keep the aircraft from moving forward
prior to the cat stroke. It holds back the AIRPLANE, not the shuttle. If you can find a detail photo of a carrier aircraft's nose gear, you will see, on the forward side, the nose tow or launch bar. I t is normally stowed in the 'up' position. Prior to launch, the bar is lowered. The transverse knob on the end of the launch bar engages with the notch at the front face of the shuttle.

In the good old days, the holdback was a machined bolt with a precisely
defined breaking strength. One end went into a socket in the aircraft
(various locations, usually in the fuselage), the other end went into a socket
on the holdback device, essentially a chain attached to the deck which
locked into a serrated track. These days, the hold back is a non-frangible
arrangement (broken pieces of holdback being a Not Good Thing on a
flight deck, not to mention one more thing to keep track of and replace). Of course, in the good old days, there was no nose tow, the shuttle was
attached to the aircraft via a cable bridle which connected to rearward
facing hooks in the main gear wells. The non-frangible holdback is
essentially a spring-loaded socket (aircraft side) and a knob-ended
deck-side fitting with which it engages.

Whichever the design, the intent of the holdback is to keep the aircraft
from moving out of engagement with the shuttle. It goes like this:

As the aircraft taxis into the cat, the deck crew attaches the holdback
and the nose tow engages the shuttle. The aircraft comes up against the
holdback (gently! gently!), and the cat operator tensions the cat to take
out the slack. If the shuttle gets a running start at your flying machine,
you'll likely lose the nosegear. At this point it is possible for the cat to
fire at any time (not on purpose, but it can happen) so the driver comes
off the brakes and goes to military power. There's a brief process
where the pilot checks for excuses not to do this again (particularly at
night), while the deck guys check for loose panels, leaks and such, and
the cat is fired. The cat pulls the aircraft out of the holdback and away
you go. Launch power varies with aircraft type and loading.


----------



## SoD Stitch (Dec 10, 2008)

Matt308 said:


> You are right SoD. Here's a good explanation I found.
> 
> The purpose of the holdback is to keep the aircraft from moving forward
> prior to the cat stroke. It holds back the AIRPLANE, not the shuttle. If you can find a detail photo of a carrier aircraft's nose gear, you will see, on the forward side, the nose tow or launch bar. I t is normally stowed in the 'up' position. Prior to launch, the bar is lowered. The transverse knob on the end of the launch bar engages with the notch at the front face of the shuttle.
> ...



Psych!

I "googled" the same on-line article you did; that's the best explanation I've seen, also. However, I understand the newer ones are reusable (don't know the details) so that the CV's don't have to stock tons (literally!) of hold-back bolts; not to mention having to pick up the broken pieces every time you have a cat launch (which could cause FOD if not picked up).


----------



## Matt308 (Dec 10, 2008)

Yeah that was a good explanation. Only thing lacking was diagrams!


----------



## HoHun (Dec 11, 2008)

Hi Matt,

>I can't sum up your technical position. I have no idea what that is.

Exactly - I didn't express any  You accidentally implied something, and I couldn't figure out what you implied accurately enough to point out that it was a misunderstanding.

So my request for a summary was not a rethorical one, and no sign that I was angry in any way ... your posts were clearly indicative of an innocent communication failure.

No hurt feelings here - in fact, I thought it was funny though I couldn't clear it up as quickly as I thought 

>I can't believe that a PC game would contain such level of detail, as this would make the game so costly as to be virtually out of reach to anyone except gov't entities.

There is nothing that calculates loads in X-Plane, but Rigs-of-Rods features a universal finite element approach and should be advanced enough to simulate aircraft-carrier interactions qualitatively (for illustration purposes, at least). No doubt that one could never expect any kind of useful accuracy for engineering purposes from it, of course.

Regards,

Henning (HoHun)


----------



## Waynos (Dec 11, 2008)

Sorry for this random question but, now that the RAF is buying its C-17's rather than leasing them, and adding more if the funds can be found, isn't it time we brought them into line with other RAF types and started calling them the 'Globemaster C.1' or similar? C-17A is absolutely fine, but its not very RAF is it.


----------



## SoD Stitch (Dec 11, 2008)

Waynos said:


> Sorry for this random question but, now that the RAF is buying its C-17's rather than leasing them, and adding more if the funds can be found, isn't it time we brought them into line with other RAF types and started calling them the 'Globemaster C.1' or similar? C-17A is absolutely fine, but its not very RAF is it.



Supposedly, they are; from Wiki:

"In RAF service the C-17 has not been given an official designation (e.g. C-130J referred to as Hercules C4 or C5) due to its leased status, but is referred to simply as the C-17. Following the end of the lease period the four aircraft will assume an RAF designation, most likely "Globemaster C1"."


----------



## Matt308 (Dec 12, 2008)

Interesting. Didn't know that.


----------

