How Big can Big get? [Archive]

Vfrpilotpb

10th Jun 2002, 17:30

Good Evening Rotorheads,

Just recently I have seen flying near the South Coast some very big almost humongous helicopters, I think they were from our American bretheren and all had a huge great rotors with side pods that my wife could use for shopping, I think they were CH53's?. but this got me thinking at what point would the designers have to stop in terms of size for a Heli, we all know that RR have produced some huge HP ratings from resonably sized engines, but at what point does BIG, become Too BIG to sustain the ability to be useful?
:)

Heliport

10th Jun 2002, 18:17

CH/MH-53E

http://www.sikorsky.com/ImageFiles/Images/SAC_Sikorsky_Aircraft_Corporation/Global/US-en/stallion.jpg

The CH-53E SUPER STALLION and MH-53E SEA DRAGON are powered by three 4,380 shp General Electric T64-GE-416 engines, can carry 16 tons of supplies, cargo, vehicles, artillery, and troops for 50 nautical miles. They operate at cruise speeds of 170 knots and, with air-to-air refuelling, have unlimited range.
The CH-53E is the most powerful helicopter in the U.S. military inventory. It's cleared to 73,500 lb. with external loads. It's the only helicopter that can lift the 155mm howitzer, its crew and ammunition - or an aircraft as heavy as itself.

http://www.stopstart.fsnet.co.uk/smilie/roundeyes.gif

Dave Jackson

10th Jun 2002, 18:20

http://www.moon-sun.com/photo/airshow98/mi-6.jpg

Send Clowns

10th Jun 2002, 18:27

The Mi-26 (NATO nickname "Halo") above is roughly the size of a C-130 Hercules ... :eek:

RW-1

10th Jun 2002, 19:44

I've been in the CH-53E, nice .... when it's flying.

Man, that Halo is like the C-5 of heli's :D

advancing_blade

10th Jun 2002, 19:53

Dont ya just love those 53's. I read a review that said it can perform a complete roll, which is incredible for such heavy iron (maybe Nick can verify).

As big as the Halo is, our Russian cousins can do even better (only built three though), the MI-12 Hommer.

MI-12 (http://www.helis.com/timeline/mil.htm)

Gives me PITOT envy
:D

Lu Zuckerman

10th Jun 2002, 20:08

For a production helicopter the Russians have outdone everybody else. However for a design concept that never entered into production the largest helicopter ever built was made by the Hughes Tool Company back in the 1950s. It was a pressure jet helicopter and was so big it could straddle a large army tank and lift it. I have searched the Internet for a photo but no luck so far.

This helicopter would dwarf any present day helicopters.

:cool:

Heliport

10th Jun 2002, 20:38

vfrpilotpb started the thread "..... at what point would the designers have to stop in terms of size for a Heli, we all know that RR have produced some huge HP ratings from resonably sized engines, but at what point does BIG, become Too BIG to sustain the ability to be useful?"

And advancing_blade asks if it's true that a CH-53 can do a complete http://www.stopstart.fsnet.co.uk/smilie/roundeyes.gif?

Coriolis

10th Jun 2002, 20:58

What happened to the big Boeing? I remember seeing photos of a mock-up 'Super Chinook' which was proposed in the 60's?/70's? - when BAH (sigh) had 234LRs carrying 44 pax the biggie was said to accomodate something over 200 - gives you an idea of the size.
But apparently stalled not because of engine power but no available gearboxes to transmit the power. At the time we thought maybe the Lynx-style conformal gearteeth might have been a way forward but nothing heard since....
Never did work out what it might be used for, though - perhaps installing offshore jackets in one lift?

Nick Lappos

10th Jun 2002, 21:49

Yes, the H-53A/D has done full aerobatics, I have enjoyed these maneuvers myself. The control authority and flight envelope are quite inpressive on the Stallion. I do not know of any 53E doing approved aerobatics, mostly because aerobatics had passed from the must-do to the why-do catagory in the intervening time. The CH-53E (70,000 lbs) and its smaller predecessor, the H-53D (42 to 50000 lbs) are no slouches. They are very big, fully operational in every way, and unrivaled in their practical ability to be used in combat. In other words, it is not a circus trick when these aircraft go to war.

Big machines have problems all to themselves, mostly due to the issue of low frequency fuselage modes that can create problems, especially in helicopters, where exciting vibrations are plentiful.

The most massive helicopter ever is the Mi-12 or V-12, which had two Mi-10 rotor systems laterally displayed on strong pylons (that's two 115 foot rotors!) and 26,000 horsepower. Only a few were built, it is rumored that dynamic interactions prevented full development. The fuselage is about the size of a good sized airbus. I saw this in a museum in Russia, it is unbelievable.

here is a web site found with one yahoo search:
http://www.flying.no/mi12.htm

The practical Russian big bird is the Mi-26, which has a 105 foot rotor, and can carry about 20 metric tons of cargo for short distances. It is in full production, with over 200 built so far. I know the test pilot and designer of this bird, they are Gorgen Karapetyan (a Hero of the Soviet Union for his personal bravery at Chernobyl) and Marat Tischenko (now a professor at University of Maryland). The Mil team is a first class group. The Mi-26 does suffer a bit from the old Soviet way of qualifying aircraft, with short lives and relatively high maintenance, due to the abundant manpower and the little competition of the old days. Even so, the Mi-26 is impressive! Here is a web site that discusses the Mi-26 at some length:

http://www.fas.org/man/dod-101/sys/ac/row/mi-26.htm

ShyTorque

10th Jun 2002, 22:00

The MI-12 was wider than the wingspan of a B747. It therefore needed a very large airport to operate from and very strong taxiways to support it.

It was so large that smaller fixed wing were more versatile. It became pointless as it was not commercially or militarily viable to use a rotary wing to do a fixed wing job. As a technical exercise it was an amazing project but that was about all.

Think about trying to refuel such a large aircraft from small bowsers, or even trying to supply enough of a load to make it worthwhile to operate it. Simply too big for its own good.

Dave Jackson

10th Jun 2002, 22:34

Here's another BIG helicopter. It's currently in production and it matches the Mi-12's 115-foot rotor diameter.

The gross weight is a 'tad' less than the Mi-12.

Helios (http://helios.etsmtl.ca/index_ang.htm)

:D :D :confused: :mad: :D

widgeon

10th Jun 2002, 22:43

Surely the 50 nautical miles in CH53 spec is missing a digit somewhere ?

Thomas coupling

10th Jun 2002, 22:53

I still have the 1988 'Horizon' video showing the Jolly Green doing a loop and barrel roll. It looked effortless. The video of the Super Lynx taking the world speed record, also shows the pilot doing full aerobatics...and by comparison..big is best;)

I suspect that practically speaking, the most 'effectively utilised' heavy helo today, then, is the skycrane?

Hoverman

11th Jun 2002, 00:07

widgeon
I'm not sure there is a digit missing - operating at MAUW.

Nick?

widgeon

11th Jun 2002, 01:22

http://www.hqmc.usmc.mil/factfile.nsf/7e931335d515626a8525628100676e0c/8a583a9bef2c6f8d8525626e0048f5fc?OpenDocument

For full link.

Normal range is 540 nautical miles .

Range is 50 nautical miles with full load ( external ?) plus return without load.

Nick Lappos

11th Jun 2002, 01:52

widgeon is right on.

The CH-53E has the ability to carry an external payload of 32000 pounds out 50 NM and return under sea level 32 degrees C conditions, with all normal mission equipment and reserve fuel. It can carry 20000 lbs 440 NM, and can carry 5000 lbs 900 NM.

Here is the Sikorsky web site technical info:

http://www.sikorsky.com/file/popup/1,,185,00.pdf

Draco

11th Jun 2002, 10:02

There is a great series of three videos which show all of these helicopters mentioned above working.

One video is all about the workhorses, such as the Hughes, the skycrane and the MI26 mentioned above. The hughes has a rotor so huge that you can actually see the rotor in motion - even at that speed, the tips must have been nearly supersonic. Fascinating.

the others are edited original film about the early years (Sikorsky, Young, Kaman etc). amazing how these people built helicopters, got into them and tried to fly them without knowing whether it was the helicopter or the pilot that was at fault. Awe inspiring.

I'll post the details if anyone is interested.

The Nr Fairy

11th Jun 2002, 10:09

Draco :

Details please. My nipper will go ape for some stuff like that.

Draco

11th Jun 2002, 10:25

Ok, here you are

Choppers - the Early Years, Choppers - The Workhorses and Choppers -The Helicopter at War

all published by DD Video, 5 Chruchill court, 58 station road North Harrow Middx HA2 7SA but you can probably get them from a large video shop or amazon.co.uk if they are still around. Again, there is some boring nonsense in all three, but some of the original footage and interviews with the pioneeers are just amazing.

The Nr Fairy

11th Jun 2002, 10:35

Draco :

Got your email as well - ta very much.

turboshaft

11th Jun 2002, 14:36

Lu,

You're thinking of the Hughes XH-17 (see http://www.russian.ee/~star/vertigo/mcdonnel_crane-r.html).

Another contender is the old Boeing CH-62 ALH (nice set of engines, which we actually ran...) - see http://www.russian.ee/~star/vertigo/boeing_hlh-r.html.

But is you're looking for REALLY big, you can't get much larger than the Mi-32 design (see http://www.russian.ee/~star/vertigo/mi-32-r.html). And they say Osprey has unusual asymmetric characteristics...!!!!!

Cheers,
t/shaft

Vfrpilotpb

11th Jun 2002, 19:10

Thank you one and all, yes after pouring over all of your great answers it was indeed a pair of CH53(E)s that I saw, going like stink and lower than us civvies normally fly, they also had the big pointy thing (ATARP) at the front, these two were followed a short time later by what looked like two Brit Army helis(biggish things) but as they were painted like Zebras it confused the eye and I still cannot say positivly what they were.

Gentlemen you have done it again, Encyclopedia PPrune, ask and thou shalt recieve many correct answers!

Thank you, and many regards to all of you.

Peter RB;)

Send Clowns

11th Jun 2002, 19:32

"Painted like zebras" they may have been junglies - Seaking HC Mk 4s, used for transport primarily for putting Royal Marines (and army) where they want to be, and recovering them from where they are.

Flying Lawyer

12th Jun 2002, 02:14

vfrpilotpb
I was trying to post this picture showing a CH-53 at Sikorsky, but Heliport beat me to it. (Hawk in the foreground)
Many thanks to Helidrvr for loading it for me.

We all know Nick Lappos is an impressive man, but the MOST impressive aspect of his character is that he's not only prepared to have a lawyer as a friend - but is even prepared to be photographed with one!! ;) :D http://www.stopstart.fsnet.co.uk/smilie/arms.gif

Tudor Owen

http://pprune.homestead.com/files/picture042.jpg

Thomas coupling

12th Jun 2002, 13:15

Who's who?

The Nr Fairy

12th Jun 2002, 13:18

FL's the English one, and Nick L is the American one. Does that help ?

If not, FL is on the left, NL on the right.

ShyTorque

12th Jun 2002, 21:30

That can't be Nick, in the photo he posted himself he looked much younger (although someone had drawn a moustache on it)!

:D

Heliport

13th Jun 2002, 00:56

Shy Torque

Nick is such a gent. He's probably trying to make Flying Lawyer look better!! :D

Lu Zuckerman

13th Jun 2002, 15:15

With all of the major players having their pictures posted on this thread I thought I would would post mine. That way when you think of me as an idiot (as some of you do) you can know what I look like. The hair is a bit shorter and the beard is clipped a bit closer but everything else is still the same.

http://pprune.homestead.com/files/Iconoclast.gif

:D

Hoverman

13th Jun 2002, 17:18

:confused:

Hey Lu
Didn't know you were a 'Private Dick' as well as everything else. :D
Did you get your picture of them bonking in the woods? ;)

widgeon

13th Jun 2002, 17:33

Funny how people dont look at all like you expect sometimes.

Smoketoomuch

13th Jun 2002, 17:58

Hmmm, Lu, did you used to be in 'The Goodies'?
http://www.billoddie.net/gallery/present/images/gripyarns_jpg.jpg

Hoverman

13th Jun 2002, 18:32

:D :D :D

the coyote

13th Jun 2002, 23:36

Mr Wile E Coyote, at your service...
http://www.geocities.com/TelevisionCity/3081/genius.gif

Agaricus bisporus

14th Jun 2002, 00:48

Heliport, the CH 53 is the only helo "that can lift an aircraft as heavy as itself". Nay Nay Nay, thrice times Nay!

Even the lowly Hughes 500 can do that, as could, if memory serves, the (sigh) BV234. As can a great number of other helicopters, I suspect. Even a Jet Ranger on skosh fuel would just manage to lift a lightweight sibling.

That MiL 26 is quite a beast, but I recall reading it's flight manual at Helitech some time ago and being impressed by the limitations, max 30' aob being one. I got the impression it had to be pussyfooted about, not like the upside-downey CH53s. Since then I've seen the '26 in operational theatres, and on the rare occasions when they ever turned a blade in between being crawled over by hordes of engineers they minced about like they were made of egg shells. My impression was that it was not half as operational a piece of kit as it might appear.

Heliport

14th Jun 2002, 00:55

Thanks for the correction, Agaricus.
Only goes to show it's wise to be sceptical about manufacturers' claims!

Over to you Nick Lappos!:confused:

Agaricus bisporus

14th Jun 2002, 01:15

Some impressive links above to the Hughes monster (what must that have sounded like, tip burning jets and 88RPM?) and that incredible triangular Russkie thing.

Makes me think of a couple of utterly bizarre hybrids from the ?80s?, one called a ?Helistat?, a blimp with a four S58s stuck onto it. Didn't it crash spectacularly? Anyone got a link? Were there any others like that, or is my memory playing tricks?

I just wish I had pictures of the effect of the awesome downwash of that late lamented (sigh) helicopter on a row of RAF canvas dunnies and an ice cream van from a 200' hover. Talk about the proverbial hitting the fan! And the Station Commander still called up to say thanks for a wonderful display - we thought we'd destroyed their families day and were in the proverbial ourselves.
:)

Nick Lappos

14th Jun 2002, 01:37

In defense of Heliport. who is only guilty of sins of omission, and of Sikorsky literature, which has never failed me:

At sea level and 32 degrees C, the 53E will recover an external load equal in weight and drag to itself, fly 50 nautical miles, drop the load, and return 50 NM home, with reserve fuel. All within normal limits.

I know of no other aircraft that can do this, although there might be one. The Mi-26 can barely lift its empty weight, I believe it, with no room for the mission fuel.

The Helistat was the previous Frank Piasecki research project, prior to the pathfinder ring tail he is now building. It was 4 H-58 fuselages connected to a frame that supported them, with controls connections, to a gas bag. It had enough lift to barely float the whole mechanism. The rotor thrust was all available for lift and control, a potential 50,000 lb lifter. The frame proved structurally inadequate, perhaps due to those pesky low frequency structural modes I mentioned earlier in this thread. The frame broke and the Helistat crashed after only a few seconds of flight, and one of the pilots (all four hulks were manned:( ) was tragically killed. The poorly thought out concept was properly abandoned at that point.

Heliport

14th Jun 2002, 07:26

Grovelling apologies to Sikorsky, Nick and their lawyers! http://www.stopstart.btinternet.co.uk/sm/notworthy.gif
My mistake, I now see a full stop (period) in the original which I missed in my cut and paste.

Thought this pic of a Sea Dragon doing a low pass over Nick's boat was good.

http://www.sikorsky.com/Images/SAC_Sikorsky_Aircraft_Corporation/US-en/MH53E_AMCM_sled.jpg

Hoverman

14th Jun 2002, 10:18

Oh Gawd!
Now we'll have a picture of Lu's boat.
Reminds me of the old song which went somehting like "Anything Nick can do, Lu can do better!" :rolleyes:

Agaricus bisporus

14th Jun 2002, 17:30

Nick, thanks for the stats, that's one awesome toy, and certainly the Mil26 isn't even in the same ball-park.

And to Heliport, apolgies if I stepped on your statement a little hard, no offence meant.

More info on the Piaseki pathfinder ring tail anyone, never heard of it!

Cornish Jack

14th Jun 2002, 18:45

Re. the CH53, in the early 70s we were operating Whirlwinds at Akrotiri when our colleagues from across the pond arrived with their mine-sweeping 53s to 'sweep' the Suez Canal. They were freighted-in, in C5s, and re-assembled. Given the rather pre-historic nature of our own 'mounts' we had to have a look at these modern behemoths. Jaw droppingly huge and massive amounts of (to us) esoteric equipment. One thing which fascinated all was a switch on the right seat overhead panel, labelled 'ZEROISE'. :eek: :confused: Nothing like that on the 'whirly', of course, so we had to theorise as to its function. Various opinions were expressed but we eventually came to the conclusion that it was the ultimate in modern flight protection. If, by chance, or otherwise, one got oneself into the $%^£*** all one had to do was press the 'zeroise' switch to return everthing to its original state, thus saving the day. :) Well, it seemed a reasonable accompaniment to such overwhelming technical modernity!! ;)

Heliport

14th Jun 2002, 19:27

Agaricus

None taken I assure you, thanks for pointing it out.
It'll teach me to be more careful when I cut and paste. :)

Vfrpilotpb

15th Jun 2002, 06:12

Good Morning (well it is here)

Yet again an absolute massive amount of information from you all, and some nice piccie's,
TC, I thought you would be able to spot the FL in that nice typically sardonic pose, with that yellow tie, dead give away!

One question always leads to another, so being eager to find out I am intrigued at the angled rear rotor on the CH53, it has no doubt been discussed before but could any of you explain the beifit it offers to the Heli, I think the Blackhawk also has an angled one also??

Peter R-B:D :D

Nick Lappos

15th Jun 2002, 08:22

VFRPILOTPB,
This was posted on rec.aviation.rotorcraft a few weeks ago. I will have it bronzed, and placed next to my daughter's baby shoes :D :

The tail rotor is canted on Black Hawk, CH-53E, Comanche and on the S-92. The angle gives a vertical component of the tail rotor thrust, so the aircraft gets two benefits: Increased free lift, and the ability to let the CG further get further aft. Let's slice each one out:

1) Free lift. The 20 degree tail rotor tilt gives you about 34% of the tail thrust as a lift force (sin 20 = .34) In a Black Hawk that is maybe 450 pounds of free lift, while reducing the yaw component only about 6% (cos20 = .939). This allows the H-60 to carry 2 more troops. S-92 carries about 650 pounds more payload because of its tail.

2) More aft CG. When the third engine was added to the H-53, the canted tail rotor was used to allow that big T64 to be placed directly behind the transmission. The lift of the tail rotor allowed the CG to be moved back to accomodate the new mass distribution. Comanche's tail has 13 degrees of tilt, mostly for control of observability, so that no sensors are looking directly into the fan housing and duct.

3) The free lift costs some in mixed response to gusts, and to pedal inputs. Left pedal makes the nose go down, and vice versa, so we have to mix the mechanical controls to prevent that and also make the AFCS smart enough to help out. On the H-60, even the stabilator gets involved, with lateral acceleration fed into the amplifier to help keep the nose steady in gusts. It all works fine, but took some effort to straighten out at first. I flew some of the early handling qualities development flights in the YUH-60A's back in 1975 and we had some fun making everything work well together! It all does quite well, I think, but it would be a lot simpler if the "Free" lift from the tail rotor was not used!

Nick