Ground effect cargo planes to avoid the U-boat threat?

[Draconis]

Imagine a fleet of huge ground effect cargo planes flying (or skimming along) between Halifax and Liverpool. Skimming along at 120 Knots carrying a 100 ton cargo making the passage in a little over a day.

Immune to U-boats and largely protected from the Luftwaffe by the RAF these craft would be used for high priority cargo and personnel.

But could such vehicles have been built in the early 1940s considering the aeronautical knowledge at the time about ground effect? To carry 100 tons how big would it need to be?
How much horsepower would be needed to fly a plane that size in ground effect? How many and what kind of engines? How much fuel? I should have studied aviation engineering in college.

I don't have a sufficient understanding of the engineering involved to say whether this idea is complete ASB or if there is some merit to it. I'm guessing these vehicles would be far more efficient than the Spruce Goose as they would be taking advantage of ground effect flight.

On the other hand there is the North Atlantic sea state and weather to contend with. Big waves and icing and high winds. If you have to skim higher to avoid waves you start losing the benefit of ground effect. However like an airplane if the weather goes bad you can turn around and/or divert somewhere and wait out the storm.

I think they would be 100% safe from U-boats. If the flight crew spots one along the flight path they can fly/skim well around it as well as reporting the sighting. Perhaps my planes should have a dorsal turret or two equipped with a couple of 50 caliber Brownings in case a Condor gets past the RAF patrols?

If this could possibly have been a feasible project then these craft could have been mass produced like Liberty ships. Flocks of a hundred at a time skimming across the Atlantic to the U.K. What a sight that would have been.

 

[wietze]

the A90 orlyonok has 30T payload and has 2 103KN jets and a 11.000Kw turboprop so lets assume for a 100T payload you would need at least double that propulsive power.
seems way out of reach for the era

 

[jsb]

Can you use huge ground effect cargo planes flying (or skimming along) between Halifax and Liverpool most of the year round, or is the north Atlantic a bit choppy to jump from one wave to the next? Waiting is ok but not if its most of the year?

 

[Draconis]

the A90 orlyonok has 30T payload and has 2 103KN jets and a 11.000Kw turboprop so lets assume for a 100T payload you would need at least double that propulsive power.
seems way out of reach for the era

But that vehicle was designed for a much faster cruising speed of about 250 MPH.

 

[jsb]

The other problem is Capacity a liberty is 10,856t v 100t so you need 100 times the voyages to carry the same cargo, might need a huge number of planes to carry a significant%?

I would have thought they would get used to resupply Malta first due to speed and conditions? That or using them as ASW escorts for the OTL convoys, they could easily keep Uboats down under water and then regain the convoy.

 

[Draconis]

Can you use huge ground effect cargo planes flying (or skimming along) between Halifax and Liverpool most of the year round, or is the north Atlantic a bit choppy to jump from one wave to the next? Waiting is ok but not if its most of the year?

That is a good question alright. The North Atlantic has its good weather and bad.

 

[Draconis]

The other problem is Capacity a liberty is 10,856t v 100t so you need 100 times the voyages to carry the same cargo, might need a huge number of planes to carry a significant%?

I would have thought they would get used to resupply Malta first due to speed and conditions? That or using them as ASW escorts for the OTL convoys, they could easily keep Uboats down under water and then regain the convoy.

That's true they would have to have been built in the thousands and I don't know how economically practical that would have been.

As ASW planes it would be a waste. They're too big and bulky for that job. That's what VLR B-24s should be for.

Malta? If these skimmers are going to war zones they will require sufficient air cover or they would be sitting ducks.

 

[wietze]

But that vehicle was designed for a much faster cruising speed of about 250 MPH.

which is why i didn't scale up linear, the biggest issue with a ekroplan is creating the airflow under the vehicle that produces the groundeffect.
in the case of the A90, the jets produced the groundeffect, the turboprop the forward propulsion

Malta? If these skimmers are going to war zones they will require sufficient air cover or they would be sitting ducks.

in effect as vulnerable as the german Me-323

 

[Draconis]

which is why i didn't scale up linear, the biggest issue with a ekroplan is creating the airflow under the vehicle that produces the groundeffect.
in the case of the A90, the jets produced the groundeffect, the turboprop the forward propulsion

What if you use a bigger wider chord wing? And for lower speed flight jet engines are losing efficiency.
Not that jets are a consideration in a 1940 aircraft. But a cargo WIG built for 120 MPH would need a different airfoil design than a Russian warplane.

 

[jsb]

Malta? If these skimmers are going to war zones they will require sufficient air cover or they would be sitting ducks.

I was thinking they might have the speed to get in to Malta covering the last dangerous part at night, 120Knt would allow them to be a long way off by daybreak, I think Alex to Malta is far more likely and they should be able to carry far more with the fuel savings v flying to Halifax!

As ASW planes it would be a waste. They're too big and bulky for that job. That's what VLR B-24s should be for.

VLR B24s in 1940 would be cool but I would settle for this as an escort if it actually has the range to cross the ocean? I don't think Bulk matters as all its doing is spotting & keeping Uboats down so they cant catch a convoy again.

 

[marathag]

The other problem is Capacity a liberty is 10,856t v 100t so you need 100 times the voyages to carry the same cargo, might need a huge number of planes to carry a significant%?

The Hughes H-4 Hercules, aka Spruce Goose could carry two Sherman Tanks.
It never got out of ground effects, so we will use this
Now the Liberty Ship
per the wiki
on 6 October 1942 John W. Brown began loading her first cargo – 8,380.9 long tons (9,386.6 short tons; 8,515.0 metric tons) of cargo destined for the Soviet Union, consisting of two Curtiss P-40 Warhawk fighters, 10 M4 Sherman tanks, 200 motorcycles, 100 jeeps, over 700 long tons (784 short tons, 711 metric tons) of ammunition, and over 250 long tons (280 short tons, 254 metric tons) of canned pork lunch meat

 

[Not James Stockdale]

Ground effect can be maintained over calm surfaces at up to about fifty feet, but becomes disrupted by seas over three or four feet, which are very common in the North Atlantic but less so in more confined areas like the Mediterranean or Black Seas. A southern routing out of the Gulf Stream and away from the polar jet might be more feasible than always running straight from Halifax to Liverpool. Such a routing might go from Puerto Rico towards the Azores to utilize the more calm weather at the center of the North Atlantic gyre.

Beyond the question of the physical feasibility of GEVs in World War 2, you also have to consider operational issues that might arise. For example, running planes full of soldiers across the Atlantic might require plane guard ships and markers strung out across the ocean, which would not only present easy targets for U-boats but also tell the U-boats, which are equipped with anti-aircraft guns, where to wait to ambush the aircraft. The operational complexities of this system obviously must be compared to the OTL method of getting soldiers across the oceans, which was with fast oceanliners escorted by cruisers.

My judgement is that GEVs would be more useful in intratheater roles (supporting island outposts and the like) than in intertheater roles.

 

[TonyA]

From what I've heard so far, sounds like this doodad would be a Pacific rather than Atlantic option, with utilization more along special mission lines rather than the everyday. Trouble is, can't think of what those special missions might be for a huge naval/amphibious force island hopping their way to success and glory across the Pacific.

 

[Glyndwr01]

https://en.wikipedia.org/wiki/Burnelli_CBY-3

The CBY-3 "lifting fuselage" was an evolution of the earlier Burnelli UB-14. Burnelli worked as a designer at Canadian Car and Foundry (CanCar) in Montreal, and the CBY-3 was intended for bush operations in northern Canada. The sole prototype was extensively tested but failed to gain a production contract.
Up-scaled maybe?

http://www.robertnovell.com/the-fly...rcraft-and-a-man-named-burnelli-july-17-2015/

 

[phx1138]

I immediately thought of the H-4, too. Payload is too limited, & cost of operation is too high, for them to carry anything but the highest-value freight, like (frex) radars, maybe troops. Heavy & bulky cargo will (virtually must) still go by ship, for the same reason it does today.

 

[Draconis]

I immediately thought of the H-4, too. Payload is too limited, & cost of operation is too high, for them to carry anything but the highest-value freight, like (frex) radars, maybe troops. Heavy & bulky cargo will (virtually must) still go by ship, for the same reason it does today.

High economic costs are often accepted in war time operations if the goals are met. Consider the Hump airlift. Would these ground effect craft have produced satisfactory results? I'm wondering if designs and test prototypes had existed for these vehicles in the late thirties then in the beginning of the Battle of the Atlantic when ship losses were so high there would have been a rush to build and use these ground effect craft. But would they have performed adequately?

In retrospect the H-4 was a waste of resources but its construction was motivated by the U-boat panic.
Perhaps as other posters have mentioned there could have been a number of these GEV built but then used in some other theatre for some other purpose after it become apparent the the Germans would not be able to halt the North Atlantic convoys.

 

[Nik]

FWIW, some of the really big inter-war flying boats relied on 'surface effect' to assist take-off & landing, hence their big 'ears' on the 'boat hull'. And, IIRC, the early German Atlantic flying boats often flew very, very low ie in 'surface effect', until they'd burned enough fuel to climb out...

Scurries off to find a long-hoarded magazine (1995 !!) with article on WIGs...
Aha !! The BIG problem is CL generally shifts forwards as craft climbs slightly. Get it wrong, and craft back-somersaults. There are four known solutions...
Lippish Reverse Delta
Three-wing 'power assisted Ram'
Jorg Tandem aerofoil
Cambered Ram Wing...

Aside from that, and disregarding the absurd Spruce Goose, IIRC, there were big 'conventional' flying boats designed to patrol the ocean and support Pacific outposts. In addition to the famous Coronado, the later, little-known Martin Mars had a remarkable capacity-- 133 troops or 15 tonnes payload. Several survivors from the limited production run were recycled as 'water bombers' for fire-fighting !! I suppose the proven design could be stretched to six engines and 20+ tonnes...
https://en.wikipedia.org/wiki/Martin_JRM_Mars

 

[Carl Schwamberger]

Just to cut losses to submarine attacks faster cargo ships might be the better option. If each additional knot of average convoy speed cuts losses by 5% where is the practical limit of gain with 1940s cargo ship propulsion? What about 2% reduction, or a 7% reduction?

 

[phx1138]

Just to cut losses to submarine attacks faster cargo ships might be the better option. If each additional knot of average convoy speed cuts losses by 5% where is the practical limit of gain with 1940s cargo ship propulsion? What about 2% reduction, or a 7% reduction?

If your goal is only to reduce sub losses, there are vastly easier ways. One, put aircraft over the departure & assembly area, out of Newfoundland. Two, make convoys bigger. A third, less easy, build more corvettes.

Explain, first, why these don't, won't, work before you say a large WIG aircraft in the '40s will even appear on this duty, I'm afraid.

 

[CalBear]

Even the biggest aircraft (or ground effect hybrid) will pale compared to a cargo ship. A Liberty Ship had a deadweight (i.e. cargo capacity) of almost 11,000 tons. That means that one Liberty Ship could, on a single trip, carry 52 times the cargo of the modern AN-225 (and the -225 is a marvel of design). The Ekranoplans (i.e the Caspian Sea Monster), far and away the largest rgound effect platform ever created had a max cargo of ~200 tons (slightly less than the AN-225). Moreover it had a max range of under 1,000 km, it is 3,600 KM from Halifax to the UK, 5,200km from New York. That doesn't even begin to consider the difference in cost (the H-4 ran $2.5M in 1942 USD, or around 1/3 more than a Liberty Ship).

Both of these jet powered aircraft had more power available than anyone in the early 1940s could even dream of (each of the AN-225's six engines has 10x the thrust of the Rolls-Royce Nene, and each of the Ekranoplans' TEN engines had 5.5x the thrust of the best wartime WAllied jet).

It is extremely unlikely that a ground effect aircraft with a useful payload and trans-Atlantic range could be manufactured today. In the early 1940s it wasn't even a reasonable fever dream.