Sunday, 12 October 2014

Now for something completely different!!

Douglas DC-3 Dakota G-AMYJ (KN 353) was retired from flying in 1999 by Air Atlantique at Coventry and used as a spares source for the remainder of the fleet. She was acquired by YAM in 2001 as an engine-less shell with the Stb'd outer wing missing.
She arrived on low-loaders and was pieced back together by a small team led by ex-RAF Senior Engineering Warrant Officer George Astley MBE.

G-AMYJ on the dump
The restoration initially was for static display and she was fitted with incorrect ex-Catalina engines and props. The interior was fitted out for 'paratrooping' and the cockpit pieced back together for static display.

As time went on it became clear that it was possible to bring her back to 'life' and two correct Pratt & Whitney Twin Wasp engines were acquired via Air Atlantique as well as flight-worthy propellors. These were installed late in 2009 and a restoration programme was started including a complete rubdown and repaint carried out by myself and Peter Kondras in 2011 into correct RAF Olive Drab colours.

The task to resurrect her was vast, The electrics were in a mess and a number of hydraulic, pneumatic and engine components were missing or U/S.
The team came together for the task and included; George Astley, Graham Sharp, Grant Sparks, Brian Watmough, Bob Emmett, Peter Kondras, Marie Taylor, Ray MacElwain, Ken (radio Ken) Sanderson & Myself. Help came from many outside specialists including; Air Atlantique, CFS Engineering Coventry, Yorkshire Hydraulics, Battle of Britain Memorial Flight & Mark Edwards - DC3 Licensed engineer and pilot on type & 'Paddy' Green - owner of airworthy Dakota N5831B, currently based at East Kirkby in Lincolnshire.

The task was long but the first engine runs were carried out by myself and George in early 2013 and all was progressing well until George's unexpected death in the Summer. This knocked the morale of the team heavily, but we ran the engines for his daughter, and his funeral service (fittingly) was held at the Museum on the same day. We also asked his daughter to unveil the aircraft's new name 'Warrant Officer, George Astley MBE' on the port side of the cockpit just before the funeral service.
One of the first engine runs

Engine runs and restoration continued and finally the decision to taxy her was taken after Bob Emmett had worked his skills on the braking and hydraulic systems.

The day Sunday 12th October was chosen and proved to be very calm, but with heavy fog. However, this gradually lifted and after the Museum's DH Devon had been put through its paces by Steve Pepper and the Devon team it was time for the 'Grand old lady' to steal the show.

As I had carried out all engine runs from the right hand seat, I decided, as I was to taxy her, then I would taxy her from that seat. Graham Sharp was in the left seat with Steve Pepper acting as 'observer' and Bob Emmett monitoring the hydraulics for any leaks or pressure problems.
The crew L to R - Graham, me and Bob

I signaled for chocks away and released the brakes and she immediately rolled forward for a brake check. It was then that I realised I had just moved a WW2 veteran aeroplane under its own power for the first time! I was wearing my Grandfather's RAF Identity Discs 'dogtags' on my flying suit, the last time they were worn in an aircraft was in a Dakota which crashed at Down Ampney at the end of WW2. My Grandfather was one of the lucky ones that escaped the crash, the pilot's sadly did not...
On the runway
After a short roll of about 200 yards I drifted her to the left and with a quick stab of the right hand brake and advancing the left throttle she turned smoothly around on the runway. I taxyed back towards the team and turned her again for a longer run down the runway. We carried out a power-up to 1800 RPM and she wanted to go! I brought the RPM back to a fast idle of 1200 before releasing the brakes. A run of about 1/2 mile followed and it surprised me as increasing either engine RPM by as little as 100 RPM caused 'drift' in either direction. I turned her around and powered the engines up for the watching Fire Team before a brisk taxy back and a final power-up to clean the spark plugs of any oil before shutting her down.

Just after shut down - thumbs up! 
We were all very happy with the results of the day and at no time did I feel frightened of the aircraft, It took a bit of practice to get the feel of her and it'll take quite a bit more to get anything like comfortable with her. She showed that she needs care and demands respect. I have nothing but admiration for the guys who operated them in WW2 and beyond.

Find out more about the DC-3 at

Friday, 3 October 2014

Vertical Gyro's

As time goes on components need servicing if they are to remain in a serviceable condition.

Such items include the flight instruments. Not particularly necessary for ground operations but, as XL231 is a rare and almost unique piece of 'history' and maintained to as near flight-worthy as we can get, then these items have to work.

Two such items are the Vertical Gyro's. There are two fitted in the aircraft and these control the artificial horizons of the Smiths Military Flight System (MFS) in front of each pilot. This is intergrated to a twin compass system that is also linked to the Autopilot and Nav Bombing System (NBS). Certain faults in this system can cause annoying and hard to find faults elsewhere.
Gyro with casing fitted

Because XL231 is no longer flying the Gyro's when running tend to run in one spot, the only exercise they get is when they power up to their operating speed of 35,000 RPM, or when they are subject to motion during a taxy run on the runway. This causes the horizon system to 'seize up' over time and cause odd indications on the instrument. Usually displacement of the horizon bar from level to wing low/wing high or cause Horizon bar drift. The main causes are dryness of lubrication from standing still for a long period of time (ie storage) dirt, or possible corrosion on the main gimbal/rotor assembly.
Gyro with casing removed

The original gyro's from XL231 were replaced with out of store items some time ago and these are now starting to stick as well as the original items. So, I decided to take the plunge and read the books for a solution. There is next to nobody out there who can or will advise and there are no newly-serviced items anywhere. I do know the manufacturer quoted around £30,000 to service one gyro for Vulcan XH558's return to flight and that is why the MFS system was upgraded to a modern 'Bendix King' Horizon and Compass system. totally necessary in order to fly the aircraft with manufacturers product support and satisfy the CAA.

I deduced the only solution was to dismantle the casing off of one as an experiment and read the manual. The overhaul process by the RAF involved a hermetically sealed casing for the unit. However, we have no such luxuries and have to do the best we can and keep the item as sterile and as clean as possible. I removed the casing at the join line and the internals were exposed. The fault seemed obvious, there was dryed out lube on the main gimbal and it didn't spin too smoothly. This should be totally clean and free of any restriction. this was washed off with spirit and fresh lube applied and the unit now spins freely. The casing was then re-fitted and sealed with a ring of Araldite. Originally solder but, I didn't fancy the risk of applying heat to the unit and possibly damaging it and I decided to use Araldite instead. If the experiment is successful then another unit will be similarly serviced.