Category Archives: Flight Testing

Flight Test Application, Flight Testing, Paperwork

Monday 28th and Tuesday 29th October 2019 – Flight Testing

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It’s been a month since we carried out the first part of the flight test. A couple of holidays and continued bad weather has prevented further testing but Monday and Tuesday both looked good so Rob made the trip down on Monday morning so we could finish it off.

After a cuppa we planned what we were going to do. Avionics testing on the first flight, the Airmaster and feathering on the second flight and during the third flight which would be for 2 hours we would test the autopilot and complete any outstanding general flight tests.

To ensure that we achieved the 15 landings required by the LAA to validate the flight test Rob suggested that we carry out some Touch and Go’s at Lydd EGMD. A quick call to them and we were set up for that on Tuesday.

All the flights were completed at the end of Tuesday at 16:03. We logged 15 landings with a total flight time of 7:31. During the flights all aspects of the the aircraft worked faultlessly.

  1. The Airmaster was a dream to use and produced some very impressive results with maximum rpm for very sprightly acceleration and a very short take off run. Once Climb is selected we noticed a very good climb rate even at MTOW. The transition between different settings on the prop was very smooth and predicable. With the engine off and the prop feathered it reduced the drag to negligible rates which was reflected in the reduced descent rate achieved.
  2. The engine ran faultlessly and never missed a beat. It was very responsive to throttle changes throughout the range.
  3. The autopilot performed faultlessly too. It did everything that was asked of it. Tracking a flight plan, climbing or descending at a specific VS or to intercept an altitude. It even protected the aircraft by ensuring it didn’t fly outside the flight envelope.
  4. The Dynon screens are clear and easy to read. They take a bit to get used to as they are not quite as intuitive as an iPad, but they worked very well with good aural warning annunciations coupled with the display of appropriate alerts.
  5. The Bristell was lovely to fly. It was stable and had a good solid feel but very responsive when you need it. It settled on the ground during landings very nicely even in moderate turbulence. The cabin is very spacious and the seating is very comfortable. It felt that you could fly for hours and not get fatigued.

Overall I’m very happy with my decision to buy a Bristell. The options I’ve included have enhanced the end result and my decision to fit the Airmaster have resulted in an aircraft that’s a delight to fly.

So the flight tests are done and the paperwork is with the LAA. Now it’s a waiting game before I receive the permit to fly but hopefully it won’t be too long before I’ll be able to take G-MLSY for a flight myself and then take Karen for a few flights including a little tour around the Kent coast.

G-MLSY is a joy to fly and it was great to get back in the air.
One of the tests to carry out if you have a feathering prop is to switch the engine off, feather the prop and restart with a dive and then repeat with a starter restart. Both work faultlessly. Once feathered and trimmed for best glide we achieved and impressive descent rate as can be seen in the photo..
It never ceases to amaze me what you see from the air. Here a staggered river or drain reveals itself at height.
Dungeness Power station off the right wing tip. The landscape around here is quite barren.
Set up for a very turbulent final to ’03’ The Bristell handled very well and was very responsive even in these conditions. Touch & Go’s were really very easy. Land, dial up 10 degrees of flap, full throttle and away you go. On climb out with positive rate of climb, flaps away and switch the Airmaster to ‘Climb’. The rpm reduces to 5500 with no stress or fuss.
One of the things that we had noticed is the EGTs tended to be a little on the high side. During construction I made a decision to add exhaust wrap to the exhaust downpipes. This was to protect surrounding pipes and lines from excessive heat. However it seems to have an adverse effect and produce higher than expected EGT. This shows the EGTs with the exhaust wrap fitted.
I decided to remove the exhaust wrap and run the engine again. The EGTs are running up to 80 degrees cooler now so I’ve decided to leave them off now.
G-MLSY looking good after a thorough clean and ready for the next flight…
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.