Category Archives: aerobatic

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.

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!

 

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!

Exciting visit from British Aerobatic champion Lauren Richardson

At the end of the last week the ASTC had an exciting visit from British Aerobatic Champion Lauren, Richardson.

LaurenSmall1
Photo credit: lauren-richardson.com

 

28 year old Lauren has completed five seasons of flying aerobatics and three as a certified display pilot in air shows around the UK, completing 33 performances over the space of just four months during the 2015 flying season.

Whilst in Sheffield to present a lecture for the Sheffield branch of the Royal Aeronautical Society on ‘The art of the unusual attitude’, Lauren was invited to the ASTC to see the work we were doing helping to fully-certify the Game Bird 1 aerobatic aircraft. Lauren said she hopes our work will be of great interest to competitive aerobatic pilots across the UK and is watching our project very closely!

You can read all about Lauren’s work and see stunning video of her in action in her specially modified Pitts Special G-G-BKDR biplane at: http://lauren-richardson.com/

 

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!

Sometimes good things fall apart, giving us a chance to build better for the future…

After having a great week last week running the Whiffletree through the night and flying through some more of the fatigue testing cycles, we unexpectedly encountered a failure of the bolts connected to the engine mounting bracket.

That area of the aircraft is more highly loaded during testing than it would be in real life when in-flight, so it is running through the fatigue cycles in an ‘over-test’ situation. Unfortunately the bolts, which are grade 12.9 high tensile bolts, simply weren’t strong enough and had fatigued over time.

The failure caused the bolts to shear and pop off the rig, allowing the engine mounting bracket frame to bend, ripping through the weld and bening the arm of the bracket out of line.

IMG_7547crop
The sheared bolts from the engine mount bracket

 

IMG_7529crop
The failure ripped through the weld on the bracket

 

All testing stopped without any damage to the aircraft and we had to remove the whole front engine mount bracket to grind the entire weld out. This took Mission Controller Shane an entire day before we could then pull the bracket back into place and tack weld it together ready for re-welding.

The bracket was sent to our Nuclear AMRC colleagues who welded it back together on Monday. When it was returned we had some re-fitting to do, as the re-welding was done to both sides of the bracket instead of one this time. This caused the bracket to close up slightly from its usual shape so we had to jack it out to make sure it would fit.

The extra strength should serve us well as the fatigue testing continues, so taking the bracket off turned out to be a good opportunity to make some improvements and plan for future preventative maintenance; such as changing the bolts on a more regular basis.

The rig was back up and running this morning, so we conducted a 30 minute test run to bed the rig back in. We will then go round the rig, tighten everything back up and make sure nothing has moved out of place before resuming full testing again this afternoon and evening.

So even though we are only up to 54,400 fatigue testing cycles, should today go as planned, we could be back on 24 hour testing as early as Wednesday; maybe even finishing the fatigue testing completely by Friday!

Pop back next week to see what happens!

 

Making sure we have the perfect fit

After everything had been running smoothly last week, we began to notice an increase in movement and creaking of the air frame on the rig which we wanted to investigate.

Our client came in to also see what was going on and together we both decided to take off the wings of the Game Bird for a closer look. We re-looked at the bushings in the wings and realised there were a few tweaks we could make that would hopefully solve the unnecessary movement and creaking sound so these were changed and re-installed.

We also noticed on there wasn’t quite a perfect fit on the pin used at the front of the rig which was contributing to the unnecessary movement we had been experiencing. This was because it had been laser cut, which has the tendency to be a bit rough around the edges!

To solve this, we bored through with one of our lovely machines to make a bigger hole and fitted a brass bush so we could just push that onto the rig and the pin would go straight through it. Now we have a nice, tight-fitting pin which has reduced the creaking, so we are very pleased with the outcome.

All in all, everything took us about a week to complete but we are now back up and running.

Mission controller for the project, Shane, describes the plane running as “beautifully” so we have a very happy office. The alterations have made a great difference to the control so the movements are more progressive.

Shane decided to leave the aircraft to run through the night and has a webcam which is used to check the aircraft when it’s left to run alone. Unfortunately Shane has been checking it constantly through the night, much to his wife’s despair!

The plane did indeed run beautifully which was great news and this greatly increased the speed at which we are progressing through the fatigue testing cycles, having now completed 50,708 out of 71,000!

Here’s a quick video of the Game Bird aircraft during fatigue testing on our new and improved quieter and smoother rig…

 

We are going to run it through the night again which means we will be fast approaching the end of the fatigue testing cycle, when we will have another ultimate load test at high temperature to complete. Stay tuned for more news!