Tag Archives: engineering

Gearing up for a big day…

As Mission Controller Shane was away last week and the AMRC was very busy with the exciting budget day reporting hosted by Sky News here at the Advanced Manufacturing Research Centre, the team decided to spend last week re-boxing up the aircraft with insulation and heaters ready for a set of ultimate load testing this week.

The second life fatigue testing was completed successfully the week before and now that the Mission Controller Shane is back, he is currently validating the testing programmes for this week’s testing.

This week’s ultimate load tests will consist of a residual strength test where the Game Bird 1 is pushed up and pulled down on the Whiffletree rig to 72 degrees, applied by a load of 64.5 kilo newtons; the same forces applied throughout the fatigue testing.

Once complete a heated static ultimate load test will pulling down the plane on the rig first with a force of 82.65 kilo newtons, then the aircraft is pushed up on the rig plus 15 per cent of that force.

As we are still experiencing some play in one of the wing pins, Game Composites are currently assessing whether they want to complete some repairs to the damaged bushes this has caused before we go ahead with the testing tomorrow, so Game could well be back on-site with us this afternoon.

As well as Game, the Civil Aviation Authority (CAA) will also be present on-site to witness the tests and we will update as soon as possible, hopefully with some video of the nerve-wracking testing, so you can experience what the team go through when putting the Game Bird 1 through its paces!

IMG_0505
The Game Bird 1 boxed up and ready to go!

 

Passed with flying colours!

Today was a great day! Last Friday, after all the ups and downs, we finished all the fatigue testing after we reached 71 633 cycles.

With this complete it was time for us to move onto the ultimate load test, performed once before, where the aircraft gets boxed in insulation and heated up to a toasty 72 degrees Celsius. This definitely helps take the edge of the February chills we have here in South Yorkshire.

So with the airframe all boxed up as you can see in the picture, we were all ready for the residual strength test to 64.85 kN which the airframe had no trouble getting through.

When this first pre-load test was complete, we moved onto the static ultimate load test which took the Game Bird 1 up to 82.65 kN. This is the highest loading that the airframe has seen to date, so it was a tense time for all involved. The Game Composites team were on site during the testing today, so we were all feeling the pressure!

17.02
The Game Bird 1, boxed in insulation for today’s ultimate load testing.

 

Fortunately relief spread across us all when the airframe passed with flying colours. There was the odd creak which was expected, although this didn’t help with the tension levels when we were all watching!

It has certainly been a very exciting week for us here at the AMRC and guided by the Civil Aviation Authority (CAA), it is now time for us and the team from Game Composites to decide what’s next when it comes to further testing for the Game Bird 1 aerobatic aircraft!

Stay tuned!

ASTC’s fact of the week

Concorde’s first flight was 40 years ago today in January 1976!

Its maiden voyage flew passengers from London to Bahrain in complete luxury, serving champagne, lobster, caviar and fillet steak during the journey.

Concorde flew passengers at supersonic speed during its lifetime, meaning a trip from London to New York was reduced from approximately seven hours to only two hours and fifty-two minutes!

Even the best laid plans…

We’ve had a fairly good week at the Advanced Structural Testing Centre since our last post. As mentioned the customer visited us to see the aerobatic aircraft in action on the whiffletree testing rig to check out an unusual creaking sound and to review the data sets captured every 10 cycles of fatigue.

The aircraft is assembled on the whiffletree in an asymmetric way to induce twisting into the wings and fuselage as the load is applied. To achieve these torsional loads, it is necessary to mount the whiffletree on the right wing in front of the centre of pressure (CoP), to induce the correct amount of ‘twist’ in the left wing that is mounted slightly behind the CoP. Loading in front of the CoP wouldn’t happen in normal flight.

This means the right wing is not being tested representatively (it is being over tested). As the root spar of the left wing is smaller, which is the critical wing for testing; so if the left wing is good and the identical right wing with a bigger interface will also be good.

As the right wing is carrying this forward CoP twist it was necessary to put some patches on to stop the flexing of the skin inside and stiffen the assembly, hopefully preventing the unusual sounds, data and make the test run smoother.

The fatigue testing continued on Friday and Saturday morning and on Monday we felt confident enough to let the testing run through the night.

We set the testing cycle going at 4.00 pm and as all good parents do – kept a keen eye on its progress via a webcam – we do like to know what our children are up to! Just after 10pm the shutdown lights came on as the rig was no longer running. A brief investigation on Tuesday morning found the reason for this was a fatigue failure of a rig part.

The part was the thread of an adaptor where the actuator is joined to the load cell; this had fatigued and broken so the actuator could no longer put the loads onto the rig.

img_0344crop[1]

The MOOG controller had then automatically shut down safely. As the actuator became detached it fell onto the engine fairing attachment beam below the representative engine mount causing some damage DOH! This is the worst nightmare of the test engineer! Fatigue testing really does discover every little issue with the entire system.

img_5131crop[1]

The damage has not caused any structural problem to the aircraft and the customer was more pleased that we had tried to run through the night to get the test completed more quickly. Repairs were made by the customer on the same day.

We are now modifying the back end of the load cell to change the broken part to a larger diameter, this is so it will connect directly onto the actuator, hopefully minimising the risk of this failure reoccurring.

The larger diameter part is currently being machined by our AMRC apprentices based onsite at the Knowledge Transfer Centre workshop. A great advantage of being so close to our other centres here at the AMRC is the ability to collaborate closely with our colleagues and our customers, allowing us the flexibility to modify and repair parts at short notice. The apprentices are machining the modified part which should be back with us by the end of Tuesday, allowing us to start testing again on Wednesday if possible.

We are now just under 30 per cent of the way through the testing cycle, so once the modified part is fitted and we are running the fatigue testing cycles day and night, we should run through them fairly quickly!

 

ASTC’s interesting fact of the week

On 9 December 1972, the Apollo 17 mission was on its way to the last manned-mission to the moon. 42 years ago today the mission crew were halfway through a rest period, or having a snooze, during their lunar-coast on their way to land on the moon. They were so relaxed that they overslept by 70 minutes and mission control were unable to wake them as their earplugs had fallen out!

This was just over 52 hours into their mission after leaving earth, at this point the crew were 70,200 nautical miles from the moon.

Sadly the Apollo 17 mission wasn’t only the last time humans walked on the moon, it was also the last time humans have left low-earth orbit in the exploration of our universe!

The Apollo 17 mission broke many records, such as breaking the record for the longest total lunar surface extravehicular activities, the largest lunar sample return and the longest time in lunar orbit. Perhaps most interesting, is the fact that the mission was the first and only time a professional scientist has visited the moon, or flown beyond low earth orbit. Harrison Schmitt, a professional geologist, was assigned as the Lunar Module Pilot, rather than NASA training a pilot as a geologist.

The whole Apollo 17 mission is available to view in real-time, with over 200 hours of viewing at http://apollo17.org/

Passing the ultimate load test…

This week the team have completed the ultimate load test on our aerobatic aircraft under heated conditions. The test involved applying 82 Kilo newton’s (kN) of force through the load mounting bracket that acts through the main wing attachment points. The load is spread through the airframe and reacted down through the Whiffletree all under heated conditions of 72 degrees Celsius!

The ultimate load test involved loading the airplane up to replicate positive and negative g forces of 15 g. This load was applied just once in each direction and is the biggest load test the plane will complete.

It is a pivotal point in the testing programme, and takes the airframe to 150 per cent of maximum operating load so it was ‘squeaky bum’ time for the aircraft designers and a real relief that the test was passed successfully.

 

So we now have a green light to go ahead and start full fatigue testing as soon as we have made some modifications to the Whiffletree requested by the customer. We’ve installed some steel metal reinforcements to the engine mount block to ensure that the load is spread evenly through the engine mounting interface on the aircraft.

The reinforcements were laser cut by our friends at the AMRC Design Prototyping & Testing Centre and welded by our Nuclear AMRC colleagues. So we’re in good shape to start the fatigue testing cycles in earnest, getting as many cycles as possible completed before site shut down for two weeks over the Christmas break.

The full fatigue testing programme is made up of 71,633 ten second cycles of +/-10 g. This will take five weeks if we run the programme eight hours a day. These testing cycles have to be constantly monitored to ensure we are hitting the loads, that the data being received from the strain gauges is correct and to visually inspect the aircraft as testing progresses to make sure no cracks appear in the structure.

Luckily the team will be sustained by a multitude of festive snacks that have been appearing in the office this week, including mince pies and Quality Street chocolates. Although half a tub of Quality Street chocolates disappeared this morning and the finger of suspicion has been pointed at the mission’s best boy, Ed. Whether the accusations are true or not will require more verification, stay tuned.

ASTC’s interesting fact of the week round-two, a Sheffield-related achievement!

Did you know, that every single podium place from the last two World Championships and last two Olympics for figure skating, has been won on a pair of skates carrying blades made right here in Sheffield?

The blades are produced by Sheffield-company HD Sports which owns John Wilson and MK Blades. The company originates with Sheffield-based engineer, cutler and Royal Toolmaker John Wilson in 1696. John Wilson blades even provided skates for Queen Victoria and her husband in 1841.

If you are serious about your figure skating, you’ll probably be skating around the ice on a pair of Sheffield-made blades!

Keeping it in the family

IMG_4633The plane has now been on its first test flight and we should be taking delivery of the main structure early next week! We’ve been working hard to ensure the test rig (the whiffletree) will be ready for its arrival.

Samantha Biddlestone, assistant welding technician at Nuclear AMRC, has been working alongside us in the structural testing workshop to weld together various components which make up the whiffletree structure.

Samantha was a former apprentice at Nuclear AMRC and is also the step-daughter of our Mission Controller, Shane Smith.  Shane was keen to get Samantha involved with the project when he discovered parts of the whiffletree would need to be welded together.

IMG_4659When asked why he enlisted Samantha’s assistance Shane said “I’ve worked in the university since I was 21 and in civil engineering most of the test rigs are welded together. I actually did most of the welding on the majority of the big test rigs in the civil engineering laboratories but if I did the welding on the whiffletree parts it would be nowhere near the standard that Samantha can do. She’s good – really good, and I’m not just saying that because she’s related! We needed someone like her to make sure the whiffletree looks the part but also works as we need it to.”

Samantha is thrilled to be part of the project. Not only does it allow her to develop her skills and work collaboratively with other AMRC groups, it also gives her the opportunity to be involved with an exciting project that’s new to the AMRC.

Image Captions

Top right: Samantha Biddlestone welding parts of the whiffletree

Bottom right: Samantha looking a bit grubby after a welding session.