The History of Airborne Aircraft Towing

As we approach the RAF’s 100 year anniversary year it is interesting to note the absence of information about airborne towing, a discipline that has been proven to be effective over many years and one which continues to be used by all major air forces today.

During early combat air operations, low payloads and fuel loads meant the utility of air power was compromised.

A solution was needed that allowed operators to escape the constraints of existing engine technology and aerodynamic knowledge, and so airborne aircraft towing was born.

These initial efforts required operators to connect towing line whilst still in flight, synchronising airspeed and altitude being the major technical and flying skill challenge to overcome, as can be seen, it was a very hazardous activity

Attempts to mechanise the process were introduced but it did not remove the need to attach the towline whilst in mid-air.

Airborne towing was used extensively in the interwar period by the RAF, especially in Iraq and wider Middle East. It was also adopted by some civilian aircraft operators in order to extend the distance mail flights could go without delays caused by refuelling stops.

The ‘Express Mail’ route between London and Sydney was one such example and in 1932, set the world record for fastest letter delivery, smashing the previous record by 47 hours and 56 minutes.

By the late thirties, however, airborne towing had reduced in popularity due to improvements in engine technology but in the Pacific Theatre, the huge distances meant that the technique had somewhat of a revival.

The image below shows a US Boeing B-29 bomber being towed towards Tokyo on a bombing raid in 1944.

As can be seen from the image above, US engineers had replaced the traditional flexible tow rope with a new design, a fixed bar. This fixed bar was better able to cope with the increased stresses placed on it by virtue of greater towing thrust.

As WWII closed, airborne towing was finding use in a number of air forces, the RAF for example.

Although the RAF chose to stay with the tried and tested flexible tow rope, the construction of this rope benefitted considerably from work done on flexible pipelines used for the D-Day PLUTO fuel transfer system, especially the helical reinforcement technique.

As the Cold War progressed, variations on the basic theme included formation towing, asymmetrical towing and in some cases, unequal towing where smaller aircraft were used to tow larger aircraft.

During the 1982 Falklands Conflict, the RAF made extensive use of Airborne Towing and many commenters have since said that without airborne towing, the conflict may have been very different.

Attempts by Argentine forces to use their Chinook helicopters in the airborne towing role were not a success, likely due to their poor understanding of the overall concept and lack of suitable tow ropes.

The design of the tow rope has also changed considerably, instead of rubber hose to provide flexibility and natural fibres to provide strength, modern tow ropes make extensive use of composites and experiments are now being carried out with carbon nanotubes and graphene.

The most experienced airborne helicopter towing operators are the US Marine Corps.

The image below shows a towing operation underway. The underslung load adds considerably to drag, without the Hercules, those CH-53 would struggle to achieve any kind of operational range.

What does the future hold for airborne towing?

There will certainly be some use of the technique for unmanned aircraft and a number of research activities are underway for the robotic attachment of the tow hitch, an area that continues to cause problems and requires a great deal of training for what is a very perishable skill.

I will finish with an image of a towing test rig, a reminder that however glamorous airborne aircraft towing is, engineers still need to take care of the little things, without them, airborne aircraft towing would be impossible.

 

About The Author

Think Defence hopes to start sensible conversations about UK defence issues, no agenda or no campaign but there might be one or two posts on containers, bridges and mexeflotes!

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12 Comments on "The History of Airborne Aircraft Towing"

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Not a B-29! B-29’s were powered by Pratt & Whitney R-4360-51VDT “Wasp Major” Radial Engines. Photo’s are of a KB-50J, which were powered by Pratt & Whitney R-4360-43 Turbo-Compound Radial Engines and a Pair of General Electric J47 Turbo Jets…

ArmChairCivvy

A good one… again!

Bobbie Ball

Very informative thank you. I now have a new found appreciation of the art of airborne towing.

DavidNiven

Thanks TD.
Another great piece on subject’s that are often overlooked but are essential for sustaining ops.

I believe during the early to mid 90’s the RAF were experimenting with sending horror bags along the cable to the crew in a way of reducing the exorbitant costs of RAF hotel bills at the time.

The ‘Sustainment of Nutrition In Flight’ or SNIF tests as they were known at the time were only a partial success.

During a flight in an RAF C130 I seem to recall my unit was involved in one of the horror bag SNIF tests. After flying a few hours towards our destination we experienced horrific and very uncomfortable buffeting to the aircraft that lasted for a longer period than I was comfortable with to be honest, and once everything had settled down the always helpful aircrew began handing out our SNIF bags form large black sacks which I assumed were ordinary bin liners but on reflection after the event believe they were constructed from some sort of lightweight insulation.

It is in this area of the experiments that the tests always seemed to have problems, as the contents of the SNIF bags were subjected to the extremes of temperature during the transfer the main food stuff within the bag such as pasties or sausage rolls was always frozen in the centre and at times quite un edible, the yoghurt on the other hand was always perfectly chilled.

Do you think we should look again at this method of wringing out every available hour from our air crews while reducing costs on plush accommodation or do you think that the technological leap in materials science to produce the required insulation to be too far off with our present capabilities?

W_W

I once heard a campfire story about a guy proposing to use the towline to deliver fuel to the aircraft being towed. That guy, a sapper by the way, has been put in an asylum and never heard of again.

Nice April 1st story. I particularly like the picture of Argentine Chinook failing to tow…n

Mark

after being mesmerised by the skills required of airforces of the world to conduct such towing activities the navy not wanting to be left out thought they had a better way!

comment image

DavidNiven

Is’nt that the towing training the US aircrews are required to master prior to a Type 45 being added to carrier group?

Analyst

I wouldn’t want to admit how long it took me to realise.

I was reading down it, seeing the pictures, and thinking “but… but… no!”

Alan Erskine

Towed or refuelled? Most of these images are of aircraft being refuelled.

Alan Erskine

I have no sense of humour for April Fools rubbish.

Bronco46

In the British vernacular is “towing” synonymous with what we call aerial refueling in the colonies.

wpDiscuz
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