Monthly Archives: Sep 2019

Flight Testing

Tuesday 17th September 2019 – Flight Tests Begin

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Well today’s the day for G-MLSY to take to the air for the first time. The LAA has approved Robin May as test pilot and Maypole was approved as the test site. As it was a bit short notice only a few people were able to attend but it was great to have the support of Dave, Nic, my Grandson Elliott, cousin Anne and her husband Charles and of course Karen whose idea it was for me to buy the Bristell in the first place.

The day started early with me ensuring that the plane was ready for it’s maiden flight. Everything had bee checked and double checked. The fuel tanks were drained and 15 litres added to enable the first flight to be carried out with minimum weight.

When Rob arrived we agreed the fight test approach and schedule and I briefed him fully on the instruments, prop and engine controls.

Rob getting comfortable before the first start.

Then it was time to go but unfortunately things didn’t go quite to plan. Basically there were three issues that cropped up during the day.

  • The harnesses that are supplied by Bristell UK don’t seem to be supplied by Bristell and need to be modified. When we tried to use them, but in practice they didn’t tighten as they should so they needed to be modified.
  • The left hand wing has a supply and return line that according to a technical drawing on the Bristell UK site are supposed to be crossed when connected to the fuselage pipes. Apparently this was changed in 2016 so there is no crossover now. Unfortunately the technical drawing wasn’t withdrawn so I followed it and included the crossover. All the previous fuel flow tests were carried out successfully however it’s now apparent that the fuel was being supplied from the top pipeline as the tanks were full after completing the fuel level calibrations. Earlier, when I drained the tank and added 15 litres per side for the first flight it uncovered the problem. This resulted in the engine stopping due to fuel starvation during the warm up. There was much scratching of heads as according to the diagram the pipes were connected properly. We ran a test on the right tank and the engine ran with no sign of fuel starvation. I took a punt and uncrossed the lines and repeated the test with a long taxi run and full power tests. After 10 minutes of testing it was quite obvious that the problem had been fixed so the first flight took place.
  • The canopy unlatched on its own. It seems that in the absence of any instructions for fitting and adjusting I had taken out all the slack in the mechanism. Whilst it meant that the canopy unlatched easily when the button was pressed it also meant that if there was any twist in the fuselage it would activate the mechanism and unlatch the canopy – a bit like a ‘hair trigger’.

I think the items above demonstrate the downside of the Bristell. Whilst the aircraft is first class the lack of a comprehensive manual that covers details like those above means that you’re always filling in the gaps. Of course you are building an aircraft so you need to be able to work things out but when there are critical items that need to be done exactly as designed by the manufacturer then they should be documented in detail. I expected an inventory and build manual when I took delivery but never received either.

After resolving the issues that we found Rob carried out 2 flights during the day. The videos below are the takeoff and landing of the last flight of the day.

https://1drv.ms/v/s!Au02Zz1cs6-RgbccF7-ZF7eT6XPyLw

And landing

https://1drv.ms/v/s!Au02Zz1cs6-Rgbcu1aoFqIiNHEcyTg

The day ended well and Rob and I retired for a steak and a beer to discuss the day and work out roughly what the second day of testing would consist of and I am looking forward to my first flight in G-MLSY as observer.

Flight Test Application

Monday 9th September 2019 – Flight Test Application

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I’d planned for the flight test permit application to be processed whilst I was away in Llanbedr on a gliding trip for a couple of weeks. I’d been checking the LAA website to see if there was any change in the status of my test flight application. On Friday 6th I saw that the application had started to be reviewed so was surprised that today I received a note from the LAA that they had reviewed my application and had a few queries that needed clarification.

More specifically these were the points raised:

1. I had not listed the Manufacturer’s options like landing lights, wing lockers etc so I needed to supply a list.

2. I needed to supply some photos of the servo installation to prove that I had installed them as per the Mod that I was repeating.

3. I needed to confirm that I had fitted the harnesses as supplied with the kit?

4. I had transposed the aft and forward figures on the W&B report so that needed to be corrected and resubmitted.

5. There was a query on the W&B report but that turned out to be a mistake by the LAA.

6. I needed to confirm the full designation/part number of the Airmaster propeller that I had fitted. I thought I had but apparently there was another designation that I needed to get from Airmaster themselves. I rang Airmaster in New Zealand and confirmed the full designation.

7. I had set SIL=1 on my ADSB transponder as the GPS250 was now capable of using that level of integrity but I was told that I needed to downgrade to SIL=0.

8. The last thing was to supply details of the Radio aerials I had used for my VHF Comm and Transponder so I sent photos and part number information.

These were all very straightforward to deal with Jon Viner of the LAA. The engineers there take calls from LAA member between 1400-1600 each day so the first thing I did was to call Jon and discuss the issues in detail. Jon was very good and allowed me to use email to give my answers to the queries.

After a few emails and phone calls during the week Jon presented the paperwork to Francis Donaldson and I received the test flight certificate for when I returned home on Saturday with a hope of a first flight on Tuesday 17th September.