G,day from the Goldfields.
Boy, this deadline came around fast! It has been a steady month at the club, with no serious write offs or incidents. It was good to see Brian Gibbs out at the field again after a long absence whilst his world was being radically rearranged (read, first baby!) Congrats on the little one Brian, and it was good to see your flying has not suffered for your absence.
Our beginners, Jarrad, Tom, Daniel, and Peter are all progressing well, with Jarrad close to going full solo, with the others close on his heels. The enthusiasm displayed by newcomers always helps to lift the general atmosphere of any club and I thank them for their attendance.
I will report on the new projects mentioned at the close of the last article now as promised. The Sig Wonder converted to electric by Trevor Parnell is showing lots of promise. It flies remarkably well, and with the modifications to the motor specs that Trevor proposes it will improve even more. It is a little unusual to see a Sig Wonder belting around the sky without a howling IC motor up front, but the performance suggests great things to come. If you are interested in talking to Trevor about the specs of the wonder I will include his details at the end of this article for you.
Peter Oxenham has not at this time finished the Hovering Cobra, however I envisage it will be reportable in the next article.
At long last, some four years since the project was started, I am happy to report that the Caribou has had its maiden flight. It was one of those rare occurrences in life where everything went right on the day to give me the results I had been hoping for. The weather was great; we scored a good day amongst dozens of poor ones. It was cool and overcast but visibility was still good. The breeze was very light, consistent and blowing directly down the preferred runway. It didn’t take long to set the model up, fuel it and get the motors running. The motors seemed to be performing beautifully on the bench, so I directed my helper, Trevor, to put it on the ground and we started with basic taxi evaluation. The left motor seemed to be a little weak at idle so I did most of the taxiing at a fair speed, definitely not very scale like. The model revealed that it is very solid on the ground, perhaps the best model I have ever taxied. I felt so happy with the way it seemed to be performing and knowing that I had done a number of thorough checks of all the control movements and programming I decided to tell Trevor that I was going for it. Trevor held the tail for a few seconds at full throttle, and then on my word released the model. It picked up speed slowly for the first couple of meters and then proceeded to accelerate rapidly. As it neared the end of the strip I fed in a little up elevator and the things got decidedly interesting. The model pointed its nose straight for the heavens and climbed to about six meters with me rapidly feeding in more and more down to try and get it to level out. It then proceeded to overreact and headed straight for the ground. I had visions in my mind of a very rapid end to a short relationship as I struggled to get it to respond. I managed to pull it up, but not before it gave the ground a good belting for a few metres. I was unable to react quickly enough whilst it was on the ground for that split second to pull the throttles back and the model decided that it liked the first taste of flight so it took itself off again. I was able then to calm things down and climb the model to a safe height. It became apparent immediately that it was necessary to fly at no more than about two thirds throttle to maintain a scale like speed and not gain height. The design of the original aircraft as a STOL platform was very apparent. What was also apparent from the take off and the way the plane was handling; prone to climbing with throttle applied; unstable on turns and snapping into a spin when I tried to apply the airbrakes was that the CG was incorrect. With this knowledge and the knowledge that as the fuel depleted the CG situation would only worsen I decided to make the first flight a short one. I carried out one low pass and then went around and committed to landing. Not knowing if the model would stall out at low speed, I applied the flapperons to assist at low speed. I need not have worried as the model floated on forever, landing some distance away. Trevor and I then hurried over to the model to check out the damage we fully expected from the unplanned touch and go (should be read as slam and go) at take off. Apart from a few minor scratches, there was no damage to underside and landing gear. After the problems I had with the Trilanders landing gear it seems I got it right for this model, hitting on the right balance between strength and flexibility.
It was then back to the pits to give my ego a belting as I soon had it pointed out to me that I had made a basic mistake in calculating the CG, not allowing for the wing taper. DUH.
Fortunately I had fitted a weight compartment to the nose of the Caribou, so after a short trip back to town for lead and my balancing gear, the CG was adjusted. A second flight was then done and I was a lot happier with the feel of the model in the air, and was able to try out the airbrakes and flaps, although it did leap off the ground again at take off. The left motor quit on the landing approach, causing me to land short and off centre, but generally I was happy with it.
The day deteriorated somewhat after the second flight, so I decided to park it up for the rest of the day. Trevor suggested that I paint the mufflers flat black to make them less noticeable, and it was after removing them at home the next day that I made a startling discovery. Looking into the port of the left engines muffler, I was horrified to see that the manufacturers had not finished machining out the waste material from the junction between the port and muffler body and in effect the port was reduced to about one quarter of its full size!
How the engine ever reached full power and performed as reliably as it did is beyond me. As this motor seems to be low on compression I have deducted that the excess back pressure and resultant heat during the running in of that motor has prohibited the proper seal from developing between piston and liner. Stay tuned to this channel for a full report on the response from the dealer. Hopefully I will have the engine repaired or replaced as soon as possible so that I can get some air time before the rapidly approaching Nationals. To be honest, I am more nervous about the Nationals than the first flight of the model, having never competed in any class at any level before. My experiences in Busselton will be reported in this journal at a later date for your entertainment!
Best Wishes
Tim Bailye.
Trevor Parnell
0890913957.
HELLONWHEELS@Bigpond.com