How Big can Big get?
 

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?
:)

CH=53s? Is this what you saw?
 

CH/MH-53E

http://www.sikorsky.com/ImageFiles/I...n/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

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

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

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

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


Gives me PITOT envy
:D

Size does matter
 

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:

So, 2 questions running .....
 

vfrpilotpb started the thread 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?

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?

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

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.

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

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

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

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?

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

Nick?

http://www.hqmc.usmc.mil/factfile.ns...c?OpenDocument

For full link.

Normal range is 540 nautical miles .

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

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

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.

Draco :

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

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.