The Story of the R100 and the R101 II - Too Big To Fail

Last time on "posts as big as airships" we read the background for a fantastic engineering competition, where private industry and the British Government would try to build the best airship, and the winner would get a nice fat contract to build four more airships to create a unique skyship airway system to connect the British Empire. We also met the R100, the scrappy underdog of the competition. Somehow, Vickers took a leaky hanger you could hide a cathedral in, some aluminum sheet, some Yorkshire farmers and almost no machines, and managed to construct a seven hundred foot airship that worked. The overdog when this project started was the R101. The men of the Royal Airship Works (RAW) had it all - a blank check and the overt support of their government in this competition, and the engineers of the Airship works saw the R101 as England's big chance to take the lead in LTA technology.

The R101 flew before the R100, and did a minimal amount of flight testing before the R100 even got outside. It was also, briefly, the pride of a nation. When R101 was completed in 1929, she was the largest flying object yet built by humanity. Slightly larger than the R100, she was 223m or 731 ft long. She initially displaced 5 million cubic feet and like the R100, was literally the length of a Ocean Liner. Nearly every aspect of R101 attempted to set new standards in airship design and air travel. Her engines were diesel, her frame stainless steel, her controls electric. Her passengers would have been flying in a level of luxury that even the richest people today don't have access to. To quote But for the Millionth Chance: "she contained two miles of longitudinal steel girders, six miles of booms, or smaller girders, and eight miles of side and base struts, making 18,000 struts in all. The bracing cables that pulled her huge sides represented a total length of 11 miles; and she carried 12 miles of webs and 27 miles of tubing of various kinds. Four hundred and fifty thousand rivets held together this flying Leviathan."
 On October 12th, 1929, she was walked out of the hanger for the first time to the cheers of thousands. It was estimated that some four tons of dust blew off R101's outer cover when she was led outside. She was then walked to the nearby docking mast. Between October and November 1929, it is estimated a million people made the trip to see her moored.

After so many years of work, that the R101 was actually flying must have been a great point of pride to the men and women of RAW. The only people, I imagine, who didn't share that enthusiasm were the airship's engineers. For they knew a secret: even as R101 floated at the mast, her triangular tail making her look like a gigantic silver skyfish, they knew the airship had a serious design flaw. She was badly overweight, and not only couldn't fly to India; she couldn't have flown to Manchester with any significant payload.

Where There's a Flame You are Gonna get Burned

To keep moving backward in time, I think its worthwhile to go over the previous projects the Airship Works did. Many of the mistakes of the previous projects informed the basic engineering decisions of the R101. After the failure of HMA No.1 in 1911, The British had many successful LTA projects, mostly blimps, which actually saw a fair bit of use during the First World War. There was also a concentrated effort to try and master fully rigid airships during World War 1. Armstrong, Beardmore, Vickers, and even Short Brothers were all contractors who would end up constructing airships.

HMA No. 9: A project after (really?!) HMA No.1, it was started in 1913, only to be stopped, then started again in 1915 - only being accepted in 1917. Roughly the size and capabilities of a M-class Zeppelin, it did at least one war patrol over the North Sea but was used mostly for training and developing the baseline for developing a production rigid airship. It was scrapped in 1918.

The 23 Class: While HMA No.9 was developed and constructed, in 1915 engineers designed what they hoped would be the first production class of rigid airship. The 23 class was just under a million cubic feet in displacement, and was near - but did not reach - the performance of the P class Zeppelin. If it had taken off in 1915, it would have been highly impressive, but the R23 first took flight in December 1917, and thus was now hopelessly behind the times. They also were slightly overweight; the Admiralty wanted 8 tons of payload out of the series of four airships, but the max they could deliver was six. Two of these airships were involved in the destruction of a German U boat in 1918 in conjunction with two destroyers, though these ships were used mostly as trainers. They were scrapped in 1919.

The 23X class: the Zeppelin L.33 in September 1916 crash-landed in Essex. The crew escaped and set her ablaze, but she was so low on hydrogen already (hence the crash) that the wreck mostly was intact for British intelligence. Two airships were constructed based on L.33 - two more were going to be built, but further intel gleaned from Zeppelin wrecks allowed a new class to be designed. The R27 and R29 were once again around the displacement of the P class, but managed to meet the disposable lift goal of eight tons. Taking to the sky in the summer of 1918, R27 burned in a shed accident after two months, but R29 served in many a combat mission over the north sea during the penultimate days of the war. She was also scrapped in 1919.

The R31 class: like the Germans, the British tried building rigid airships out of wood instead of metal. The results were initially really positive: first flying in the summer of 1918, the R.31was faster and considerably lighter than expected. In a disastrous mistake, however, the wood was unvarnished and untreated, so the first time it got wet the wood warped, making the ship unusable. A second ship was completed, and was used - once again - for training and testing until 1919.

R33 ready to launch.

The R33 class: the continuation of the 23X class (IE created from gleaned intel from Zeppelin wrecks) the R33 was a British approximation of the Zeppelin R class. Displacing a R-class like 2 million cubic feet, both the R33 and the R34 were the most successful rigid airships to date. R33 was launched in 1919, and flew until 1926 under a civilian registration, providing a great deal of testing information for the R100 and R101 program. She was retired when structural fatigue began to show in the airframe. R34, of course, flew across the Atlantic and back again. Her next flight after her transatlantic adventure she struck a hill in Yorkshire, and then limped back to Howden, where moored in strong winds she was damaged beyond repair.

The R36 class: Zeppelin 'height-climber' wrecks inspired the commissioning of three similar British airships, though only one project survived the war's end. Initially aiming at a 17,000 ft ceiling, the war's end saw her converted to a civilian airliner. Once again, the ship was R-class-ish in displacement, (2 million cubic feet) and 675 feet long, the airliner was never used: she was damaged and hung up in a handling accident, and then the R38 disaster made the British Government temporarily loath to spend any more money on hydrogen airships. She remained in the hanger until 1926, when she was then scrapped.

Pretty sure this is R38 under construction.

The R38 class: started on the basis of the wreck of the L.70 Zeppelin in which German Naval Airship Commander Peter Strasser met his fate, this class was also started as a airship to patrol the North Sea. We covered the R38 accident last time, though in the story of the R101, it had two important effects: one, it disrupted airship activity for a time, and it deeply embarrassed the Air Ministry.

As a kind of TL;DR summary, the British rigid airship experienced was mixed. Their home-grown designs seem to have under-estimated the sheer difficulty of making a rigid airship to German standards, and were under-performing. The results from analyzing Zeppelin wrecks were much more useful, however, complacency or possibly arrogance was still in the mix, as was demonstrated by the R38 disaster. The institutional knowledge and in particular operational experience of the Germans seems to have been paid little mind, as if these things were easily replaced with pluck and a can-do spirit. It should also be mentioned many of the engineers responsible for the R38 Disaster were now employed working on the R101.

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R101 construction started in 1927 after two years of design work, and like the R100, it would finish in 1929, with engineering work being done as the rigid framework was erected in Cardigton. Unlike the project at Howden, the Royal Airship Works had its pick of skilled industrial workers and craftsmen as Cardington was located in Britain's industrial heartland. One innovation of the R101 project was fairly extensive use of subcontractors, in charge of major subsystems, such as the frame and the engine. The engineers of RAW couldn't be happier at their big chance, as many of them had be advocating the use of Airships as airliners since the Great War ended. Lt. Col. Vincent Richmond was the 'Assistant Director of Airship Development (technical)' - the Chief Engineer. Unlike his counterpart in Barnes Wallace, he was more of a engineer-manager: he let his underlings handle specific subsystems. That said, he was no slacker,  worked 18 hour days for weeks at a stretch, especially when knotty problems needed to be untangled - Lt. Col. Richmond had been a engineer involved in LTA projects since the start of the Great War, and had been instrumental in making Britain's blimp program a success. In fact, it gave him his nickname: Dope. Now as this is a comedy forum and I guess we could be pretty mean about that, but nicknames were treasured in the Royal Navy - having one showed you were one of the boys more than rank ever did, and I guess let's go with the hip-hop definition, meaning 'totally awesome?' (He got the nickname as he figured out the importance of doping outer covers to make them more durable.) The two other heads at RAW were Major G.H. Scott, former commander of HMA No.9, and later the R34 was a man who since the end of the Great War had been in charge of generating experimental information regarding airships. Wing Commander Reginald Colmore was the head of airship development at RAW, and the other two men's superior. He too had been kicking around LTA experimental work since its inception.

The political head of all these men was Lord Thompson, who we've already met. The chief political operator, he believed quite whole-heartedly in the future of LTA travel, going so far as to think that airplanes were overrated.He presided over a parcel of Air Ministry Bureaucrats, who had something close to his authority in dictating aspects of the project to RAW. None of these people actually knew anything about airships. The memory of the R38 disaster had a profound influence on the bureaucrats of the British Air Ministry. Such public embarrassment of HM's government tragic loss of life would not be tolerated, and "SAFETY" was made the top concern of the R101 project, and I imagine any number of elegantly formatted memos were circulated on the subject.

That was not the only goal of the project. As there was money for any number of side-researches, it soon became accepted that R101 was going to advance the state of the art for airships, while at the same time winning the competition. A third goal then emerged of being the most luxurious airship ever constructed - what had started as a spate of competitive airship building soon became a effort to make a large leap forward in aeronautical technology generally. This ambition was quietly the start of he problems.

 The first big departure for the airship makers was in the construction of the frame itself. On the basis of tests of  National Physical Labratory, stainless steel was chosen as a construction material over Aluminum. The idea was that stainless steel could provide better support for less mass. I can't evaluate that claim, but R101 didn't need the tension wires that R100 had. Manufacture of the girders was subcontracted out to Boulton and Paul, who by all accounts did a fantastic job constructing the girders. Working to 0.001 of an inch tolerance, the frame of R101, at any rate, gave no structural problems wheresoever. This choice of material pleased the Air Ministry extremely, who gave press releases saying that with stainless steel construction was the safest and best material for airship construction, one that rendered a R38 style disaster impossible.

Assessing if the unusual construction material was the root of some weight issues later is extremely difficult. Though a new material choice seems an additional complication when the engineering team as a rule always took the thicker gauge for Safety!'s sake. In addition to this, it was only in the final months of the R101 project that the consideration of weight generally was even considered.

Can I just stop for a moment here and tell you something about airships and weight?

Weight is a consideration no matter what vehicle you are building. Colin Chapman's famous dictum of "subtract weight and add lightness" works in most vehicle contexts, not just cars. That said, airships and other LTA craft are perhaps the most sensitive of all vehicles to excess weight. Their ability to be vehicles is entirely dependent on how much useful payload they can get out of their static lift. Their safety in bad weather and during malfunctions is also entirely dependent on how much extra lift they can call on. Designing an airship without considering weight is much like designing a submarine without considering buoyancy, or a rocket without considering thrust - it's a consideration fundamental to your success or failure. How this happened when the chief engineer of the project had a decade's worth of designing LTA projects is just baffling.

Anyway, another example of Safety! at the R101 project was the construction of an entire structural test ring at Cardington, (at a cost of 40,000 pounds) which was tested to destruction. Despite that the rules for certification laid down by the air ministry dictated all structures be mathematically proven to be strong enough, the R101 did a fair bit of empirical testing as well - during initial construction. Anyway, This was a big waste of money, especially as R100 had made do with math to confirm the durability of structural rings. At the same time, the government in 1926 spend money refurbishing the abandoned R36 simply because the Air Ministry thought it'd be useful. Once this refurbishment was complete, the government decided the whole thing was unnecessary, and scrapped R36 instead. {note 8/1/18: the R36 was originally going to do a test flight to Egypt. However, in what was in retrospect a worrisome development, it was calculated that R36 simply couldn't fly in tropical conditions.} Meanwhile, R101 engineers had requested a machine to aid in calculation. The machine cost 50 pounds, and could turn a two day equation into a job of two hours, but the request was refused, with the Air Ministry added that they were insulted by requests for such needless expenditure.

A closeup of some of that grid work.

The tail, with a crow's nest at the rear tip.

R101, as mentioned last time, used the same "pre-doped" canvas sections that R100 would use, and used gold beater's skin for lifting cell construction. The lifting cells themselves posed an unexpected problem. The structure of R101 was strong enough to do away with the cables that were used to reinforce the rigid framework, but these cables also were used to secure the lifting cells. Michael Rope was the engineer in charge of the gasbags as the British called them, and he decided to devise a novel solution, instead of just going with cables. Each lifting cell was roughly pillow-shaped, and Rope devised a restraining method where the tops of the lifting cells would be restrained by cables, and then allowed to float independently of the hull. This meant motions of the hull would not be transferred to the lifting cells. Rope also designed the safety pressure valves for the lifting cells. For reasons lost to history, they were much more complex, and crucially, much more sensitive to pressure changes than Zeppelin valves. I can only guess this might have been inspired by the Safety! campaign by the Air Ministry, but a perusal of airship accidents might have given a different view of these valves. The Shenandoah it is true, might have very well had structural failure when its valveless cells expanded dangerously during the fateful thunderstorm that tore her apart, but that was one incident, compared to many hydrogen airships exploding due to valves doing the wrong thing at the wrong time. I gotta reiterate here how important these valves are to the safe operation of a hydrogen airship; you can't be in any sense safe without the valves working properly in all conceivable conditions. By even messing with such technology, Rope and the R101 engineers were taking a huge risk. An interesting question here is if the sensitivity of the valves arose from Rope's basket arrangement for the lifting cells, or vice versa. I can't really find an answer in my readings.

A lifting cell in its frame - probably during R101's later surgery.

At any rate, these valves were extremely sensitive, and would valve gas if the air pressure changed even a little. They would also valve gas if the ship rolled more than five degrees, (an angle not uncommon when at the mooring mast in good weather) or if the lifting cells shifted, or if they had pressure exerted on them from other lifting cells. This last condition would be prevailing, as Rope's method of securing the lifting cells paid lots of attention to securing them to the government mandated points on the hull...but very little attention to securing them from other movement. Rope even managed to put the valves in an inconvenient location: Zeppelin's valves were always located at the bottom of a lifting cell, not only for pressure reasons (buoyant gas always wants to escape through the top of the cell) but also so they could be easily adjusted or shut entirely by airship crew. Rope's valves were located halfway up the cell, which would mean crew would have to do some clambering up the superstructure to even see the valves, much less adjust them. Holes were placed in the bow and stern's outer cover, both to keep the interior and exterior pressure equal, and to vent hydrogen out of the tail (cause, evidently, there was going to be a lot of venting.) These holes also let precipitation in - not ideal when your lifting cells were gas-tight via lightly cured cow's intestine that would in fact rot -

Anyway, uh, we'll be revisiting these issues. Moving on -

Rope also designed all the control surfaces on R101 to act by electric servo motors. While such an approach was high tech, it was also much heavier than the conventional way of doing things. Another Rope innovation was variable pitch propellers on the front of the engine cars that were used for generating electricity for R101.

The propellers out the back of the engine cars were the drive units, and a source of many problems. The engines the R101 was considering were initially the same style of hydrogen-paraffin burning units the R100 team initially considered, and like the R100 team, they were rejected as too risky and hypothetical. The R101 staff then considered diesel engines, both for the perceived safety, and based on National Aeronautical Institute research that showed that the energy-weight of diesel fuel was better than that of gasoline. According to the Institute, it would only take 17 tons of diesel to send R101 2500 miles, while R100 would require 23 tons of gasoline. There was also a temptation to save money, as diesel was 5 British pounds a ton, while gasoline was 23. All this may be true, but I'm sure the R101 staff figured out pretty quickly that such engines didn't in fact exist. I'm sure given time the R101 team would, like the R100 team, would have moved on to gasoline engines as well - except by the time they were ready to do this, the Air Ministry had already publicized that the R101 was going to have diesel engines, the safest and best engine an airship could have. This made changing the engine a political, rather than an engineering issue. I'm not sure if the Air Ministry jumped the gun because they loved the Safety! aspect of diesels, or if the R101 engineers just didn't realize the complications of actually finding a suitable diesel engine, but once it was publicized, that was it, as far as the Ministry was concerned: the R101 was gonna be a diesel.

Now, I imagine what you are expecting is that the Air Ministry is going to contract a maker of aircraft engines and contract them to build a diesel. Well, the R101 project was nothing if not full of surprises: they instead went to Beardmore (a contractor who had built airships during the great war) and got them to modify one of their diesel engines instead. While Beardmore had a aircraft engine division, this diesel engine came out of their locomotive factory, a four-cylinder diesel originally designed for shunting locomotives in Canada. Two of these engines were mashed together to create the Beardmore Tornado, an eight-cylinder diesel engine. A bespoke aircraft diesel engine was started, and it was to have the name Typhoon, but it was not ready by the time the program ended.

Can I tell you a thing or two about locomotive engines?

One: they're heavy. Trains are made out of steel, and so when designing engines for trains, you can make them as durable (and as heavy) as you like. Weight is not a concern. In fact -

Two: heaviness is actually encouraged in the design. Extra weight in an engine is actually a good thing. Locomotives need to push against steel rails in order to move, and extra weight in the engine makes for better traction.

A Tornado mounted in an engine nacelle. Two machinists would be occupying the nacelle while in flight with the Tornado, rapidly going deaf.

So the Tornado was a 84L eight cylinder inline brute that weighed seventeen tons when all five were added together. That is more than twice as heavy as the Maybach V12s used by Zeppelin, (six, seven tons total) and almost twice as heavy as R100's engine choice (six, nine tons total). The Tornado's max power was 650 hp, but its cruising output was much less: only 475 hp. This meant that in nearly all circumstances, the R101 (which was a engine down already compared to the R100) would be underpowered.

It is possible that the engineers thought these problems could be overcome, though  I imagine some of that unflappable British confidence began to er, flap, once engineers at the Airship Works actually got their hands on a Tornado and tried to get it working. Work had already been done to have metal reversing props on the R101, but this had to be abandonded. It turns out that the Tornado, (once again, a 84L straight 8) unincumbered by a transmission, had a fair bit of torque. It had so much torque, in fact, that from idle any throttle would cause the tornado to crush the metal props like a beer can. Solid wood props fared no better: the Tornado would twist them till they shattered, or crack the propeller bosses, and the Tornado would have succeeded coring the solid wood propeller like a apple. At one point one of these failed tests sent a prop blade over three quarters of a mile away. The solution to this problem was many layers of emery cloth between the propeller bosses and the hub mounting plate, which made the fitting slightly squishy and loose, softening the forces of the engine enough to keep the propeller whole.

This lead to a larger problem: how to have reverse? Evidently R101's engineers felt themselves short on time, and went for a temporary kludge solution:they chose to take one of the engines and point it the other way, making it reverse only. Already down on power, R101 would now cruise on four engines instead of five, and the fifth would be three tons of useless weight except when docking. After the R101's "surgery" in the summer of 1930, a slightly less embarrassing solution was found: engine men would modify the engine timing in two of the Tornadoes so that they ran backward while docking and launching. Another problem with the engine: it was discovered that it had two destructive frequencies, and these was very regrettably 1) at idle, and 2) at cruising RPM. The solution was to run the engine at higher RPM when doing those two things. Until this was figured out, many fuel pipes and oil fittings were shaken to bits. Despite all these problems, the people in charge were well pleased. The chief of engine development, the incredibly named Wing Commander TR Cave-Browne-Cave, had a demonstration about the safety of diesel vs. gasoline. When distinguished visitors were touring the Works, he would show them a tin of petrol and a tin of diesel. He'd then take a blowtorch, and attempt to light the diesel on fire, and fail. Then, he'd take the torch to the petrol, setting it alight. For the finale in his 'what stuff burns good' show, he would take the tin of diesel, and use it to smother the flaming gasoline fire. This was a very convincing argument for diesel in the eyes of the distinguished gentlemen. (It should be noted the Tornadoes required starter motors -and these naturally were powered by the devil's fuel, gasoline.)

Like R100, R101 had a control car right on the bottom of the airship; unlike the R100, this control car was more of a wheelhouse than a proper cockpit. With about the interior space of a Ford Econoline van, the control car could only have basic flight controls. Navigation and ballast had to be handled in another room, at the top of the control car's ladder. This would be a disadvantage should any flying emergency ever occur.

Things most cockpits down have: brass ship wheels as controls, speaking trumpets, engines set by telegraph.

Speaking of ballast, it is an important issue on an airship, and one that is a fair engineering challenge. Because the buoyancy and trim of a airship changes with barometric pressure, the weather, and things like fuel consumption, you need a method for shifting water around to keep the trim stable. Unlike other airships of this era, the British airships lacked the colossally neat Zeppelin system of condensing engine exhaust for use as ballast. R101 did, however, have a very sophisticated ballast management system, where compressed air would force ballast water to where it was needed. This system could also be used on fuel tanks, to shift fuel around assuming there was extra space in the fuel system for it. The failure of this system was simple: whoever designed it provided no instruments by which the crew could see what the state of the system was in, or even what they were doing. This was the subject later of many sharp notes by R101's crew. These notes were ignored.

The fuel system too, (if you could forgive the pun) had its share of cutting edge technology. In addition to the ballasting measures, the fuel could be dumped in some tanks in a emergency by means of a can-opening like device attached on the outside of the fuel tank. There was a drawback, subtle (but obvious with hindsight): for trim reasons, many of the fuel tanks were located directly beneath the passenger and crew quarters. The passenger accommodation themselves strove for luxury rather than the R100's adequacy. Thankfully for once, weight consideration was a design consideration, and the wood furniture was all balsa wood, as was all the wood trim. This was given a very thin wood covering of walnut and maple to create a 'proper' wood look. Like the R100, the interior cabins had cloth walls. There was also a smoking room that for Safety! reasons was asbestos-lined.

The on board lounge, somewhat enhanced as company was coming.

The promenade, where you could put up your feet and watch the world go by.

The smoking lounge.

The dining room.

A Blimp with Weight Issues

All this complexity and brilliant engineering extracted its price when the R101 was weighed off for the first time. RAW engineers had expected R101's gross weight to be 105 tons, and for her total static lift to be 152 tons. The total weight was in fact more, 113 tons, and the static lift was less - 148 tons. Subtract the weight from the static lift, and you get 34 tons. 30 tons was the expected weight for fuel, ballast, stores and crew, leaving...a four ton payload.  This was terrible news - not only had the Royal Airship Works built a 700 ft aircraft capable of carrying little more than a pickup truck, it couldn't fly long distances with any degree of safety, or fly in tropic climates under any circumstances. (In hot humid conditions it was estimated R101 would loose as much as 11 tons of lift.)  The exotic engines, the electric servos, and many of the other cutting edge innovations had completely consumed her useful lift.

Two pictures from R101's initial test flight - the former is over London, the latter over nearby Bedford.

This fact was concealed from the outside world. The engineers and operations people were eager to start flight tests, but the Air Ministry saw publicity as a more important goal.  R101's first flight took place a few days later on October 14th, 1929 - a short flight of five hours in perfect weather, on two engines alone. (The other two forward drive engines were apparently giving problems.) This (the flight, not the engine problems) was met with rapturous applause from the British press. (The flight also flew over the Howden hanger just to annoy the R100 team.)  A longer flight of nine hours was attempted next on October 18th, (all engines were working this time) with Lord Thompson aboard. After the flight at the bottom of the docking mast, Lord Thompson met with the press,  stated he hoped to fly to India aboard R101 by Christmas, though he stated that (paraphrasing here) "he (Lord Thompson) explicitly didn't want to rush anyone, and a full experimental work up on R101 must come first, and the motto of the R101 project was 'safety first.'" You can see that this man was a fairly deft politician. As for the flights themselves, the Captain 'Bird' Irwin noted that R101 demonstrated no handling issues.

There was going to be a third flight, but the risk of a storm caused R101 to be hastily put back into her shed. On November 1st, she was walked out and docked at her mast again, and then went for another experimental flight, this time with the former Minister for Air, Sir Samuel Hoare. It was another perfect day, and R101 flew over the royal palace at Sandringham, with the King and Queen admiring the latest symbol of the might of the British Empire. R101 also had time for a proper top speed test (it was 69 mph / 101 km/h). R101 also flew over King's Lynn on the Thames, where every ship blew its horn in salute, and over the Bolton-Paul works in Norwich, which she was met with cheers by the workers who had constructed her stainless steel girders. For a day, at least, the engineering problems were forgotten in a haze of well wishing and good vibrations.

The next flight was on November 2nd, and was the first night flight. (It was also the first pure test flight, and this annoyed the R101's crew. The first officer wrote in his diary"All these window-dressing stunts and joy-rides before she has got an Airworthiness Certificate are quite wrong, but there is no-one in the RAW executive who has got the guts to put their foot down and insist on trials being free of joy-rides.")It should be mentioned that all test flights were done under a flight permit, as the structure of R101 had been certified by the experts. The Certificate could only be issued once the experts were satisfied that R101 could fly passengers in safety.

An attempt was made to study speeds over a circuit on the coast, but cooling lines broke in two of the engines, and the attempt was abandoned. It was found that even at full speed, the electric servos were unnecessary for good control. Despite her massive control surfaces, R101 could be flown by muscle power alone, like the R100. Docking at 9 AM the next morning saw minor damage to two of R101's reefing booms. It was very misty and dark, and in a slight design flaw, R101 turned off all her lights when docking to lessen the risk of igniting venting hydrogen

Docking at the mast.

The next test flight got off to an alarming start, with many MPs aboard as passengers. A sudden lurch when R101 left her docking mast nearly threw the distinguished gentlemen from their seats, and broke crockery. The cause was improper ballasting - too much lift in the bow, too much weight in the stern. This produced complaints from the flight crew - again - that they needed instruments to see what the ballast states were. The return to the mast took some time to manage, thanks to a rising wind, and as an experiment, R101 was left at her mast all night during a storm. Her crew observed the effects on her lifting cells, the only time R101 would be tested under poor weather conditions. The morn revealed an airship that had rode the storm, mostly well. RAW head Colmore said that R101 rode the conditions well, noting in a report to the Ministry that "aside from a little rain getting in and a certain amount of chafing in the gasbags due to the airship rolling, no damage was sustained."

Another officer, 'Sky' Hunt, filed a rather more critical report. Hunt observed the top girders were chafing the lifting cells rather badly during the storm, resulting in one case a rip nine inches in length, which caused a 40% deflation in that cell. The lifting cells moved around a fair bit, and were catching on little snags around the structure. What's more, he observed Rope's valves opening a quarter inch on every roll of the ship, which meant that even at her mast, in rough weather, R101 was valving gas more or less constantly. Not a good combination in a overweight airship!

Her next flight was on November 14th, and it was another short publicity flight involving a few MPs with a genuine interest in aviation, and Sir Sefton Brancker, director of Civil Aviation. Then Lord Thompson managed to inject some sitcom hijinx into the test program. He had invited 100 MPs to take a test flight, thinking that only 20 or thirty would actually accept, and was entirely surprised when all 100 took him up on the offer. The flight was scheduled for November the 16th, but the weather was judged too bad, and the MPs were turned away. Then, the weather cleared the next day, and it was decided to do an endurance test. R101 flew for over 24 hours - it was to be her longest flight - in mostly good weather, over various cities of Britian, from Edinburgh, to Belfast, and over the Isle of Man. She touched at Blackpool, crossed the straight again for a friendly overflight of Dublin, and then returned to Cardington via Rugby. She had no mechanical trouble.

This is *possibly* from the MP's lunch, although honestly there were so many publicity flights it is difficult to be sure.The man next to the waiter in the center of the photo is WC Colmore; the bald man in the foreground on the right is Major Scott.

The MP megaflight had been rescheduled for November 23rd, and when the day arrived, the weather was lousy again. It was decided that the MPs could have lunch in the R101 while she was moored at her mast. This was the cause for more shenanigans - while the R101 had a full kitchen, it was pretty small - in service she would have served crew and passengers in sittings. Feeding 100 of her Majesty's members of Parliament, especially in the style they were accustomed to, was beyond its ability. So, the feast was cooked on the ground, and then taken up the mast in chafing dishes, moved to the galley, and then brought out to the dining room. This is good sitcom stuff; somewhat less sitcom-y is that so many people and silverware overloaded the R101 - the only reason she didn't have to jettison water and oil was that strong winds gave her good dynamic lift.

The only way on or off R101 was through the entrence in the nose. Also note: "canvas screens were normally rigged on each side of the entrence to hide the 230 ft drop from faint-heated passengers."

At the end of November, R101 was walked back into her hanger, as the mast was now needed by the completed R100. So far, R101 had flown 70 hours in almost entirely good weather, and her flying, at least, had been without surprises. The Science Ministry reminded Lord Thompson in a memo shortly after R101 was put away that for an airworthiness certificate (necessary for anything beyond test flights) the R101 had to fly for 48 hours straight - and that it might be worthwhile to do some test-flying in bad weather. The engineers were eager to get cracking at the weight problem. Meanwhile, R101 was hung up and her lifting cells drained and examined for further damage as observed by 'Sky' Hunt. The results were grim: of the 16 lifting cells, fifteen had holes in them, some 4000 in all, from contact with the framework.

At this point, a summary of what R101's staff had discovered about their new airship might be useful.

1) She was underpowered.

2) She was far too heavy. She had no payload ability at all, no ability to fly at all in the warm areas the Imperial Airship Scheme had intended to service.

3) All of the new thinking around the lifting cells had produced a result that was in every way worse than the established technology. In fact, the test-flights had shown that the lifting cells were showing dangerous flaws, even with R101 operating in optimal conditions.

4) The pre-doped outer cover was a failure - it didn't have the strength needed

I think at this point it was still possible to save the R101 project, had engineers or bureaucrats been willing to deal with these flaws head on, and were not afraid to start over. The locomotive engines, for example, obviously had to go, and the lifting cells had to be revised. Some 6 tons of excess weight was removed even without changing the engines, mainly by axing the servos for the control surfaces, and removing every single fitting not needed for airship operation. (The interior got noticably less plush, with the glass windows in the prominade being replaced with celleron.) It was also decided the gasbags would be further inflated and the containment netting let out to get around 3 tons more static lift (over the objections of Rope, the system's engineer, because obviously if the system was chafing already, more inflation would put yet more chafing.) The chafing issue would be dealt with four thousand rivet patches were made and applied to the inner framework.

I mean, how hard could it be to make all that snag-free?

The Air Ministry also decided that an extra 500,000 cubic foot lifting cell would be inserted in the center of the airship. This would not be a small job, even from a engineering perspective, and it meant much of the work for the airworthiness certificate had to be redone. While it would take a few months to make a new lifting cell and the necessary framework, the Air Ministry insisted on a further delay - the Ministry wanted R101 to make an appearance at the Hendon Air Show on June 28th 1930. The Structural mods would have to be made after that.

It was at this point that the pressures on the R101 project started to mount. Formerly, work had progressed at a normal pace - but now the watchword was 'hurry up' just the attitude you want when dealing with several million cubic feet of hydrogen. Further pressures manifested themselves when it became clear Lord Thomson wanted to fly to India in September of 1930. The Lord had his eyes on being the viceroy of India, and what better way to show his worthiness by strengthening the lines of communication with the jewel of the Empire? As Christmas 1929 rolled around, it also became obvious that the economic ills in the colonies was spreading around the world to create a economic depression the like of which living people had never seen. It was clear that whatever team lost the imperial airship scheme would soon be out of a job in what would  be known as the Great Depression.

So by Christmas 1929, the team of R101 was conscious that they had bad engineering problems and little time to fix them, in the face of mounting pressures. Their only hope was that R100 would turn out as bad, or worse, then the R101. Like kids who didn't do their homework, they were hoping for a snow day to cancel school. You can understand why they resented R100 when she turned up and despite her built to a price nature, had no problems to speak of.

Part of the Imperial Airship series (of posts.)

Part 1

Part 3

Part 4

Part 5

Next: The Time of Trials