Category Archives: aerospace

Aerobatic aircraft tested by the AMRC put through its paces at top global airshow

A spectacular aerobatic aircraft, which passed airworthiness tests at the University of Sheffield Advanced Manufacturing Research Centre with Boeing, has been put through its paces (week commencing Aug 22 2016) at the world’s largest recreational aviation, experimental aircraft and aeronautics airshow.

The GB1 GameBird was the first fixed wing, light aircraft to undergo a full airworthiness test in the UK for more than 30 years.

It took to the air in the skies above Wisconsin, in the USA, at the EAA AirVenture annual airshow, which is attended by more than 550,000 enthusiasts from 80 countries.

The two-seater GB1 was developed by Lincolnshire-based Game Composites and designed to carry out complex manoeuvres in aerobatic competitions or simply be flown for fun.

Although GB1 was designed and built in the UK, it looked as though it would have to undergo full airworthiness testing in the Czech Republic until Phil Spiers, who heads the AMRC’s Advanced Structural Testing Centre (ASTC), became aware of the project.

He was determined that an aerobatic aircraft being built within 60 miles of the AMRC ought to be tested in the UK, and sure his team had the skills and experience to help Game get its aircraft approved as quickly as possible.

The Centre built a special test rig which allowed it to carry out damage tolerance and fatigue tests at an ultimate load 19 times that exerted by gravity at 72°C and simulate 20,000 hours of flying.

Following the ASTC’s work and further tests on seats, harnesses, the GB1’s fuel tank and baggage compartment, the aircraft completed European Aviation Safety Agency flight tests ahead of its debut at the EAA AirVenture airshow.

Phil Spiers said: “It’s been a privilege to be involved in proving the safety, security and integrity of this aircraft and fantastic to see the GB1 up in the air.

“This is the first, fixed wing, independently designed and built light aircraft to be certified in the UK for 30 years. Now that we have re-established this country’s capability to carry out the full range of airworthiness tests we hope other designers will chose to have their testing done here.”

Following European approval, production approval will be sought from the US Federal Aviation Authority and the GB1 is being offered for sale at $399,000 for a basic model.

About the GB1 Game Bird

The GB1 has a carbon composite airframe, is 6.9 metres long, has a 7.7 metre wingspan and weighs only 585 kg when empty. It can cruise at more than 200 knots and has a range of 1,000 Nautical Miles on 320 litres of fuel, or can carry 95 litres for aerobatics.

The GB1 is designed to be used for unlimited aerobatics, training for all levels, as well as upset recovery training, flying cross country and for pure fun, with the inclusion of a front passenger seat expanding its potential market beyond hardcore aerobatic competition pilots.

For more information about the GB1, visit http://www.gamecomposites.com/.

Details of the EAA AirVenture airshow can be found at http://www.eaa.org/en/airventure.

Plane sailing

The fatigue testing has been running really well, practice makes perfect as they say! We’ve been busy changing all the joints of the Whiffletree and replacing the engine mount bolts. This is done at approximately 60,000 cycles. We learnt some lessons during the first period when we had rig failures and bits breaking, but this means the second time round, we can monitor things better and avoid this from happening again. In addition, we made a plan with Game Composites to change certain rig components as a matter of course.

We’re currently at 61,500 cycles and we have to get to 71,663. When we run a 24-hour period it gives us 8,640 cycles, so in running another 24-hour period we will be left with only 900 cycles remaining before we reach the finish line and the golden number of 71,633.

Once we’ve reached the 71,633 cycles, this will also us to begin boxing up the airframe in insulation and the week commencing the 21st we will be doing another ultimate load test at 72 degrees Celsius and then a further ultimate load test at a 15% higher load. It will be getting hot in Catcliffe! So keep checking back for exciting news!

Stanley knives and Saturday Morning Kitchen

We starting running the second life of the fatigue testing cycles on Friday and to our delight it ran beautifully well, so ran through Friday night as well. Set designer Steve gave up time on his Saturday morning off to come and shut down the rig safely for the rest of the weekend. Always absolute dedication from us here in ASTC could cause us to miss Saturday Kitchen Live.

We came back in on Monday and started our usual rounds of inspection to find that the engine attachment bracket (the bracket that takes the main load up into the wing spars) was starting to show signs of cracking.

The solution was to take it off, do some hasty cutting up of bits of box section we had and got the whole thing welded up much stronger with the help of our friends at Nuclear AMRC. This time we’ve really gone to town and beefed the bracket it up to help ensure it won’t happen again.

It was ready to reinstall this morning and we are ready to continue with the fatigue testing again today. We have already clocked up about 20,000 fatigue testing cycles out of the 71,633 required for the entirety of the second life testing, so we are getting through it quite quickly now.

Luckily for ourselves and Game Composites, nothing untoward has happened so far during testing with the extra damage we have caused the airframe. Game Composites came in late last week and did some repairs to the rear stabiliser of the aerobatic aircraft because we had noticed a little crease was developing.

It’s quite remarkable the aircraft can be repaired. A Stanley knife is used to cut out the damaged patch of composite material on the fuselage to reveal the foam layer in the middle. The foam is removed and smeared with glue, but not just any old glue is used; the glue has what only can be described as lots of hollow tiny glass balls in it, making it lightweight yet very strong. This replaces the foam and a patch is stuck over the top with resin which we leave to cure overnight.

As the aircraft being hand laid-up (or built by hand), it’s relatively easy and cheap to repair, as any repairs can also be done by manually without having to send it back to a manufacturer. As it would at the hanger or in the field.

With the repairs to the engine bracket made, we will be back up and running with testing today and we will hopefully conclude the second life fatigue testing next week so we can get ready for further testing. Exciting things to come for us!

Time to break things!

Our client, Game Composites, have been liaising with the regulator, the Civil Aviation Authority who is doing the certification for Game Bird 1 aerobatic aircraft and a plan has been developed to damage the airframe and then test it to see how the structure withstands this damage.

This is to replicate what could happen to Game Bird 1 in a real-life situation, for example, if it were to be stored in a hangar and it was to be damaged without anyone noticing whilst inspecting the plane. The testing we’ve already completed has qualified Game Bird 1 for 30 years of air worthiness certification, but with the damage testing we are going to do, this will help further help the plane gain it’s certification.

Game Composites have been on site whilst we have been damaging the airframe. There are seven points around the plane which are to be damaged from different heights and at different energies.

To do this, we fixed a ball into a bag and tied it to a rope and attached it to a crane over the aircraft, all very high tech at the Advanced Structural Testing Centre! Hovering the ball over the targeted point and graduated the string in metres meant we knew how high up we were suspending the ball to drop it onto the marked targets on the airframe.

Damage has been caused on the tail stabiliser and the wing and we then proceeded to run a few hundred fatigue testing cycles. Unfortunately but we got some rather unpleasant and unexplained noises. After a little bit of thinking about things we realised that when heating the airframe to 72 degrees for the ultimate test we had probably baked the grease off the wing pins and the engine bracket interface pin – the joints were running dry!

We were also concerned that we have got a little bit of movement in the engine mount, because over a period of time during testing it has elongated the holes in the composite material forming the aircraft. Not a lot, but enough that the bracket it moving and creating noise. So today we have taken that load bracket out and Game Composites are going to do the repair on these holes by filling them in with resin and putting the bolts back in. Then it will set and take all the play out.

We have slid the big bolts back in the wing spar to clean them up, add a little more grease, and then slide them back in.  Hopefully that will cure the groaning noises we are experiencing.

If this all goes as planned today, we are hoping to start running the new set of fatigue testing cycles through the night again; much to Shane’s wife’s delight with his constant checking of the live feed webcam when he’s at home!

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…

On the 13 February 1923, Charles Elwood Yeager, better known as ‘Chuck’ was born. Chuck joined the US air force and flew out of RAF Leiston. During the second world war, he was shot down, escaped to Spain and ultimately to the UK and was flying again before the end of the war.

Afterwards he became a test pilot for the USAF and on the 14 October 1947 he became the first man to fly above the speed of sound in an aircraft named Glamorous Glennis, which he named after his wife.

Only two days beforehand he had fallen off a horse and broken two ribs – he was so worried about missing the flight that he did not tell the air force of the incident and chose treatment by a local vet to keep it secret!

Heres to Chuck, a living aviation pioneer!

Introducing our aerobatic aircraft, the Game Bird 1

We can now announce the creators behind the aerobatic aircraft we have been testing here at the Advanced Structural Testing Centre (ASTC)!

For the first time in 30 years we can say that full airworthiness certification of a aircraft is taking place in the UK thanks to a pioneering partnership involving a championship-winning aerobatics pilot, an aircraft builder and ourselves.

Former German National Freestyle Aerobatic Champion and aircraft designer Philipp Steinbach is the brains behind the Game Bird 1 (GB1), which is being built by Lincolnshire-based Game Composites and is intended to be the world’s most fun to fly two-seater aircraft.

Headwaters of the Ganges River
The Game Bird 1 in flight!

The GB1 has been designed and built in the UK, but Philipp and Game Composites’ co-founder Stuart Walton, faced the expense of shipping the aircraft to the Czech Republic for full airworthiness certification, until Game Composites’ met our head of the ASTC (and project Show Boss) Phil Spiers at a Royal Aeronautical Society meeting.

Phil was determined that the production process should be kept within Britain, and although it would be the first time a plane has been designed, built and tested in the UK for 30 years; Phil was sure we had the skills and experience to make it happen.

The bespoke Whiffletree test rig was designed and built from scratch right here at the Advanced Manufacturing Research Centre (AMRC) with the help of welding specialists from the Nuclear AMRC and the AMRC’s own apprentices.

Phil and the team believe that the successful completion of airworthiness tests will open the way for the testing of light aircraft to return to the UK.

You can see the aircraft’s amazing capability, designed to help it carry our impressive aerobatic feats in the video’s below.

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.

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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.

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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!