Nice weather, shame about the split pins.

Armed with all the tools and stuff I thought I might need to reattach the cabin, I returned to the airfield and pulled G-BYJA out of the hangar into the glorious spring sunshine.


I was a little surprised that apart from a couple of other owners also working on their machines, nobody seemed to be flying. At one point we were buzzed by a powered glider who appeared to be attempting to make a downwind landing into the hangar entrance. The two of us watching were quite convinced he was about to crash and started to run for cover behind the substantial walls of the hangar, but he did pull up and cleared the hangar by a small margin.


A bit later, Lynne (I think) turned up and pushed her lovely Pitts Special out with a view to doing a few circuits:

Meanwhile, I was struggling to undo the various bolts holding in the rudder pedal assembly. The bolts themselves weren't the problem so much as the fiddly little split pins. After what seemed like a couple of hours, I succeeded and removed the rudder pedals from the cabin: 

That gave me full access to all four cabin mounting points on the keel. It was a valuable exercise in learning how my machine has been designed and put together. To start with, I'm now getting a feel for the varying structural loadings. 

It hadn't really occurred to me before that when the gyro's on the ground, all the weight is totally differently supported to when it's in the air. As the weight shifts from the wheels to the rotor during takeoff, everything changes dramatically. From the wheels taking all the weight through the axles and the keel, the rotor takes all the weight through the mast: 

In this photo, I've outlined the keel (horizontal) and the mast (vertical). Thinking about all the weight of the machine and two passengers hanging from the few bolts at the top of the mast makes one hope that the bolts are all of the highest quality materials. With a MTOW (maximum take-off weight) of just 556kg, though, it pales into insignificance when compared with the 570,000kg of the A380 Airbus we flew to Singapore in - how does something that heavy get off the ground? 

Eventually I got the mounting bolts replaced with my rubber bung supports and was pleased with the results. They look substantially stronger than the original fittings, and should provide at least as much vibration protection: 

I started putting the rudder pedals back in and then realised that I needed to get back home for a bike outing. 

Problems, problems.

Tony was going out in his machine, G-BWAD, with another flyer who had some historic gyro experience as well as other flying machines, and who wished to get acquainted with more modern gyros. 


While they were out, I got G-BYJA and started my pre-flight checks. Everything looked good and normal until I looked underneath the front of the cabin. The nosewheel didn't appear to be turning as freely as it should, and then I found some loose bolts protruding from the underside of the bodywork. 


Fortunately, Viv was around, working on someone else's  RAF-2000, so I asked him what these bolts were holding. The answer was very interesting but disappointing. 


Interesting because it instantly explained the problems I'd had in turning while taxiing two days previously, disappointing because it meant that I had some serious problems to fix before I could fly G-BYJA again. With the bolt fixings having failed, the whole cabin body had dropped and  was now resting on the nosewheel, restricting its movement quite a lot. Although this wouldn't have caused the machine to drop out of the sky during flight, it could have caused difficulty in steering during landing, potentially causing a rollover accident


With Viv's kind and expert help in lending me tools and showing me what to undo, I eventually discovered that three out of four rubber mounted bolts holding the cabin to the keel (the main structural support element of the whole aircraft) had failed. It wasn't immediately obvious why they'd failed, but age no doubt had quite a lot to do with it. 


Having exposed the problem bolts, there was little more I could do until I could get replacements, so I put my poor little machine away and went home to search the internet for replacement rubber supports. 

Back at home, it soon became clear after exhaustive searches, that the original rubber mounts were probably no longer available. So the backup plan suggested by Viv was put into action. This was to make my own rubber supports from rubber bungs. Our winemaking days are long past so a quick look on ebay found Homebrewsupplies4u advertising rubber bungs for demijohn airlocks. An order was promptly placed but by the time I did this, it was the start of the four day Easter weekend, so I didn't expect that the bungs would be despatched for four or five days. Very pleasingly though, Homebrewsupplies4u did actually send them on Easter Saturday, so they turned up on the Tuesday after Easter - thanks Homebrewsupplies4u.

Other fliers at Rissington.

(This Merlin image is linked from www.miltary-airshows.co.uk)

Better flying conditions today, but by the time Tony & I were ready to fly, there was only about half-an-hour before an RAF Merlin was due over Rissington Airfield.

The Merlin is a rather big and heavy helicopter and hence has a significant downwash, easily sufficient to overturn a little gyro which might be underneath it, so due warning is given to fliers at Rissington when the RAF are expecting to perform maneuvers over the runways.

After just three take-offs and landings we had to abort as the Merlin was due shortly, so we taxied back to the hangar. Annoyingly, the Merlin didn't actually arrive on this occasion, but better that than to cause him to abort as had happened recently.

While I was waiting, a fine example of the local pheasants was strutting his stuff near the hangar with his somewhat dowdier mate, so I thought it would be nice to capture him for posterity in a few million digital bits:

While we'd been taxiing, I'd noticed that we hadn't been able to turn left quite as tightly as we had on previous occasions. There didn't seem to be an obvious reason for it, but I made a mental note that something might have changed.

I needed to get home so we left it at that for the day.