Monthly Archives: October 2015

Who needs the pasty van?

Not too much to update on this wIMG_1726eek. We’re continuing to wrap the plane up in insulation. We’ll be really good at the Christmas wrapping after this! Shhhusssh don’t tell our wives, girlfriends and mothers!!!

The heaters that will heat the plane up to 72°C are also now in place and Andy and Lawrence have been wiring them up. 72°C is pretty hot! It’s hotter than the required temperature a pasty must reach before it’s safe to eat so we’re hoping to store a few pasties in there for mid-morning snacks!

Hopefully by the next blog we’ll have successfully completed the temperature controlled static limit load test and will be able to update you on how it went and what’s next on the agenda!

ATSC’s interesting fact of the week

Today marks the 134th anniversary of the gunfight at the O.K. Corral, the result of a long-simmering feud between outlaw Cowboys and lawmen in Tombstone, Arizona Territory. Who’d have thought a 30 second shootout would be the subject of so much screen time?!

It’s getting hot in here

This week we have been making preparations for the temperature controlled static limit load test. This will involve us heating plane up to 72°cand performing a single cycle test on the structure. The plane will get pushed up and pulled down once so there’s a lot of work is going into 20 seconds worth of testing but it’s all worth it!

Show Boss Phil has been in touch with a company called SIG Technical Insulation. They kindly agreed to supply us with all the insulation material we require to insulate the plane, free of charge (he must have been fluttering his big eyelashes!). SIG pulled out all the stops to get the insulation material to us in break-neck speed. They bypassed the depot and got it delivered direct to us straight from the manufacturer in South Wales – we could get
used to this special treatment! A huge thanks goes out to SIG Technical Insulation for their support.

The team has been busIMG_1706y constructing a steel frame to lift the insulation that will surround the plane, a metre off the floor so we don’t unnecessarily heat up a lot of dead space. If we built a big box around the plane and the whiffletree as well, we would probably end up heating up around three times more the volume of air than necessary. By building a sealed chamber around just the plane, it will take less time to heat up and also use less energy in doing so, so it’s a win-win for structural testing and the environment! We are also making sure the whiffletree structure, that’s made of steel, the hydraulic actuator and the load cell are insulated too to  reduce the amount of heat they absorb and ensure there’s no adverse effects on the measurements when we do the test.

On top of the steel frame we’ve built we’ve started to build a flat table-top structure which is a bigger footprint than the plane, to allow us to sit the four big electric heaters, which will be used to heat up the insulated enclosure, on. The client fitted a thermocouple on the wing spar of the plane; the wing spar is one of the main structural points of the plane; and it’ll be that thermocouple we monitor to decide when it’s hot enough to do the test.

If everything goes to plan with the temperature controlled static limit load test,, (the plane’s design engineer is as nervous as an expectant parent so for the sake of his sanity, we hope it does!) we can move onto the next step of the plan which is to remove the insulation and perform an inspection before conduct another static limit load at room temperature. If all that runs smoothly, we will rebuild the insulation chamber around the plane and conduct a static ultimate load testat 72°c.. This means putting an even higher load onto the plane at a high temperature so it will be a tense but exciting time for us all!

If all the static load tests go to plan, we’ll have the green light to start on the fatigue test which is made up of 71,633 cycles – but more on that in the coming weeks.

Up…. And Down…. Up…. And Down….

It’s been a busy and exciting week at the ATSC, we’ve finally put the first loads on the plane and so far so good!

The client came up earlier this week and we sat down and did the TRR with them (see last week’s blog for more info about the TRR). We identified a couple of points on the TRR that we wanted clarification on so the client went away to do some further analysis. One of the points we wanted clarification on was the ride height (zero offset load) but the client came back to us after doing some further calculations with a confirmed ride height.

Basically the ride height allows us to take into consideration the weight of the plane and steel work when loading the plane during tests.  It’s a little hard to get your head around but basically when we pull the plane down during testing, the load is whatever the load is, but when we push the plane up we’ve got the weight of the plane to move as well so need to put a higher load on to the plane to account for this. As we said, it’s a little complicated but feel free to tweet us using #whiffletreetechquestion if you want us to explain anything further.

With the ride height calculations done and agreed the client came back up yesterday and we did a static load test, which is a small single cycle test (pushing the plane up once and pulling it down once), to a force of 5g.

With that test running smoothly we then moved onto doing a static limit load test, which involves putting a higher load onto the plane that the initial static load test. The static limit load test completed successfully and then enabled us to set the load safety limits for the rest of the tests.

At that point we downloaded and collated the data from the two tests and handed it to the client for them to review and analyse. The client compared the actual data with the expected data that had been calculated by the design engineer and was happy with the results so gave us the go ahead to do the low cycle limit load tes.t

The low cycle limit load test comprised of us doing 300 cycles (that’s up and down 300 times). See a short video of the plane during the low cycle limit load test below. The low cycle limit load test completed without incident so we can now continue on with the test programme!

The next step is to do a temperature controlled static limit load test at 72°C so we need to build a box around the whole structure (the plane, the whiffletree – everything!) to allow us to heat the space, and everything inside it, up to that temperature. We’ll give you more info on this next week!

As we said, very busy, but VERY exciting!

In other news, Best Boy, Ed has got a new car – unfortunately for him he’s miscalculated when his 1 year no claims discount comes into effect so can’t insure it for another couple of weeks. We promise not to wind him up about having to look at the car sat on his drive for the next two weeks!

ATSC’s interesting fact of the week

On this day in 2012 Felix Baumgartner performed the highest free fall parachute jump. He reached 39,045 meters (128,100 feet) in a helium-filled balloon before beginning his jump. Felix reached a mind-boggling maximum of speed of 843.6 mph(Mach 1.25) during his descent.

Watch the highlights from Red Bull here.

Verification, verification, verification

This week we’ve been continuing to set up the test – verifying equipment and ensuring any measurements we will be taking  are accurate and traceable.

We calibrated the displacement on the actuator we’re going to use for loading – this will tell us exactly how much the plane is moving as we pull it up and down. We’ve borrowed a height gauge from the Integrated Manufacturing Group (IMG), which is calibrated to national standards, and used this to check and calibrate our linear potentiometer in the loading actuator. Now we know that if the actuator tells us the plane has moved  50mm , we can say within 0.05mm that that’s how much it has moved! The load cell has been calibrated externally obviously not with a height gauge! But against calibrated standard load cell. We take this measurement thing very seriously you know that if you buy a pound of apples from us you’ll be getting exactly 1 pound

After all the verification and checking  we’ve installed the actuator ready for use and coupled it up to the plane. Unfortunately, there was a slight misalignment where the actuator bolts onto the loading pin. It’s only 20mm but we have to make sure everything is exactly right before we proceed any further so we’ll take it out and make it right!. Luckily for us, the job of re-aligning the actuator shouldn’t be too difficult, it’s only bolted down with four holes so we are hoping to have it done within a couple of hours and then we can re-check the alignment.

IMG_1612After this, we’re hoping to be in a position for a Test Readiness Review (TRR). At the TRR we will sit with the client and we will look at exactly where we are in the process. We will explain the progress and demonstrate to both ourselves and the client that we have prepared and checked every last detail to ensure that we are meeting the requirements of both the client and the airworthiness authorities. Once the TRR has been completed, we are hoping to be in a situation where we can place small loads into the plane and check the instrumentation for results. The client will be present for this and they can check the readings and see whether they tie in with the results they initially thought they were going to find. If everybody’s happy, we and the client will both sign the TRR. We won’t start testing unless everyone is 100 percent happy.

IMG_1611The client has also been in and modified the tail of the plane by cutting two holes and bonding two ballast boxes into which weight scan be placed to help ‘trim’ the aircraft . The centre of gravity of the plane has to be balanced and determines the peak performance of the aeroplane . Typically, the majority of the plane’s weight is in the engine and the propeller and the client wants to alter the centre of gravity slightly and this can be done by adding weight to the the tail.

Steve has just finished wiring all the strain gauges and coupling them up to the data logging system. The strain gauge wires are laid across the length of the strong floor, so we have been scrounging (by fluttering our eyelashes!) and have managed to get some metal caging we can use to cover the wire to protect the wiring from being damaged by people stepping on it.

IMG_4927 (1)Outside of the workshop, to celebrate the final of the Great British Bake Off, Phil has been busy baking and made the office a chocolate courgette cake. Despite its peculiar sounding ingredient list, everyone agreed it was extremely tasty, except Shane who thought it wasn’t sweet enough – you can’t please everyone, Phil! The first boxes of mince pies have also made their way into the office; it’s never too early to get into the festive spirit in Structural Testing!

It’s up!

The aeroplane is now mounted on the whiffletree! It went on like a dream so all our hard work paid off.

It was a bit like trying to put a spider’s legs in eight holes! All the pieces were moving around while we were trying to mount the aeroplane so we had to get some helpers from the Design and Prototyping Group to restrict the legs while we mounted it. After that it all went smoothly so a big thanks to our colleagues next door!

Steve P’s now wiring all the strain gauges on the aeroplane up to the data log (he’s tearing his hair out doing it, what little he’s got left anyway J). The strain gauges should all be wired up by the end of this week.

The hydraulic pipes arrived yesterday so we’ll need to attach them to the actuator and, because they are new, flush oil through them to ensure all the filters are picking everything up.

We also need to start doing the calculations on what loads we’ll be applying to the aeroplane – that will likely be Shane’s job.

All in all it’s been a good week and we’ve moved forward. We should be getting ready to go soon – the load cells are back and calibrated so everything’s more or less ready.

ATSC’s interesting fact of the week

This week back in 1928, Alexander Fleming discovered penicillin, the first true antibiotic.

Fleming’s downfall however was his inability to communicate his discoveries with the world – he needed a great marketing and communications team like we have here!

Also, on 1st October 1958, the National Aerospace and Space Administration (NASA) was formed!