Unfortunately, the rotors and clear parts of earlier helicopters ( especially the Bell 47 ) were made from very brittle plastic that broke easily during play.

Unfortunately, the helium filled giant metallized plastic balloon deflated by the time the dragon rolled around over two hours late.

Unfortunately, cost concerns also resulted in the use of plastic in some of the moving / operating mechanisms.

Unfortunately recent T cell biology investigations revealed that T cell nature is much more plastic than initially thought.

Unfortunately for James, this diplomatic negotiation with Spain proved generally unpopular, both with the public and James's court, with ' Arminian ' divines providing a unique source of support for the proposed union.

Unfortunately, while the Keyboard Component was an ambitious piece of engineering for its time, it suffered from reliability problems and proved to be expensive to produce.

Unfortunately, Friedrich proved too ambitious for his own good, and quickly ran the formerly profitable forge into the ground.

Unfortunately performance proved to be a major problem, and a number of architectural changes were made in order to solve this problem.

Unfortunately, Basil's asceticism meant that he was succeeded by his brother and his family, who proved to be ineffective rulers.

Unfortunately for Jones the medical establishment of Edwardian Britain was resolutely antagonistic to Freudian theory and in this context Jones ’ s early attempts to employ psychoanalytic insights in his clinical and research work proved less than circumspect.

Unfortunately, the show's stability proved to be its undoing, as the producers did not see fit to add younger panelists while the regulars aged and the audience demographics became less desirable.

Unfortunately, his metabolism proved to be unique, so everyone else at the gym simply gained weight.

Unfortunately, Rolls-Royce pushed the state-of-the-art too far, too quickly, in using carbon fiber in the engine's compressor blades, which proved vulnerable to damage from bird impact.

Unfortunately, Savery's device proved much less successful than had been hoped.

Unfortunately, Goodman proved to be mistaken about this.

Unfortunately, this also proved to be the company's virtual undoing, when Microsoft failed to renew its contract.

Unfortunately the dam proved unequal to the spring floods and for three successive years it was washed out.

Unfortunately this proved a step too far with relegation in 2009 / 10.

Unfortunately, the forecast proved accurate ; despite the parade's good luck for 51 years, it rained continuously and heavily throughout the entire 2006 parade.

Unfortunately, this system of appointing ministers to oversee the government during an Emperor's minority proved not to be a very stable political device after all.

Unfortunately, from about 1930 onwards under Severi's leadership the standards of accuracy declined further, to the point where some of the claimed results were not just inadequately proved, but were hopelessly wrong.

Unfortunately, the E60s proved unable to safely achieve speeds over 90 MPH leaving Amtrak without a practical replacement for the GG1.

Unfortunately for the Germans, the British colonisation of Rhodesia ( Zimbabwe and Zambia ) stopped them well upstream of Victoria Falls, which proved a considerable barrier to navigation on the Zambezi.

Unfortunately, flak jackets proved to be too bulky for wear within the confines of the RAF's standard bomber aircraft, the Avro Lancaster.

Unfortunately, GM's timing with this latest downsizing proved to be off the mark.

Unfortunately, their design specs proved to be a little too accurate to the creatures they were modeled on, as their primitive brains went out of control, and Grimlock almost destroyed Teletraan I, before the trio was stopped.

Unfortunately, the missile's 3, 800 lb ( 1720 kg ) weight proved to be too heavy for the Gannet, and would have required modifications to the Gannet's bomb bay to expose the missiles ' seeker heads to the target before launch.

Unfortunately, this system proved cumbersome and Raven Software did not develop this particular system further.

Unfortunately, many supporters of the various Gaia theories do not state exactly where they sit on this spectrum ; this makes discussion and criticism difficult.

Unfortunately this icon has been over the subsequent centuries subjected to repeated repainting, so that it is difficult to determine what the original image of Mary ’ s face would have looked like.

Unfortunately broad performance claims are common in the consumer marketplace, which are difficult or impossible for a typical consumer to verify.

Unfortunately, it is difficult to obtain open knowledge about changing the microcode because of intellectual property reasons.

" Unfortunately, the film is so shaky that it is difficult to be certain which speed is correct.

Unfortunately, both properties are difficult to measure objectively, and only perceptual evaluations can be performed.

Unfortunately, the business information systems of the time made this difficult to discern for the managers of the company, which may partly explain the mistakes they made from hindsight.

Unfortunately, even when the affected functional domain is known, it is difficult to predict the phenotypical consequences of a particular mutation ( see Correlation of genotype and phenotype ).

Unfortunately, not many more studies have been conducted and thus a specific amount of delay time is difficult to estimate.

Unfortunately, it is also very difficult to analyze such probes in a fully self-consistent way.

Unfortunately, the off-diagonal kinetic energy terms are usually difficult to handle.

Unfortunately, much of Bleek's working life in the Cape, like that of Lucy Lloyd after him, was characterised by extreme financial hardship which made his research even more difficult to continue with.

Unfortunately, these techniques are difficult to combine with automatic test pattern generation scan testing so they fell out of favour for later designs.

Unfortunately, this also causes it to be rather hydrophobic, which makes it difficult to deliver to body cells in solution without being flushed out of the body first.

Unfortunately, language-specific fonts also make it difficult to access to a variant which, as with the " grass " example, happens to appear more typically in another language style.

Unfortunately, many type N connectors are not labeled, and it can be difficult to prevent this situation in a mixed impedance environment.

Unfortunately this is extremely difficult to implement, since VAT is collected nearly everywhere, and it is simply too difficult to track all the goods produced.

" Unfortunately being located primarily in the south, it was difficult for Pentecostals to remain integrated due largely to Jim Crow prohibitions and racial prejudice.

He wrote, " Unfortunately there is no excitement whatsoever in what Charles Jarrott, the director, and John Hale, the author of the original screenplay, have put together ... Mary, Queen of Scots intends, I assume, to illuminate history ... yet all it's really doing is touching bases, like a dull, dutiful student ... Because both Miss Redgrave and Miss Jackson possess identifiable intelligence, film is not as difficult to sit through as some bad movies I can think of.

Unfortunately, research and development are very difficult to manage, since the defining feature of research is that the researchers do not know in advance exactly how to accomplish the desired result.

Unfortunately this design has proven difficult to build due to a lack of proper materials, namely high-temperature non-magnetic materials that are also able to withstand the chemically active exhaust.

Unfortunately, applying scaffolding correctly and consistently can be difficult when the classroom is large and students have various needs ( Gallagher, 1997 ).

Unfortunately, it can be difficult to track down the spammer — and while there are some online tools to assist, they are not always accurate.