Chris Freeman 3

Byron was busy this weekend, used 2 newspapers, 6 rolls of masking tape and 3 meters masking film resulted in this.

Work is continuing and Byron has 3d printed a pilot and been working on the cockpit detail and I think it looks good. We did have another 2 flights with it and it is a very smooth flying aircraft. We hope to start spraying this weekend so I hope the next post will have some colour to it!

Part 2 video showing the Catalina. The aircraft is quite large around 106 inch wingspan. I never actually measured it as I made new wings to suit an old fiberglass fuselage. The original airframe had 2 ST 90's but never flew and we elected to start again and build new wings and tail surfaces. Tip floats have electric retract units but the weight of the floats does cause some issues but their position has no effect on the trims. Motors are e-flight 46's with Master airscrew 12 x 6 props, 1 is a pusher and we think this is what causes all the prop noise. No idea what it weighs but it is not light. It has all the rivet and rib stitching detail on it. Flight performance is good, water handling a challenge as it is impossible to do a nice landing with it, it seems to flop into the water.

I would say you need to do what you think is right. I have studied some of Robin designs and the way he builds and am never sure how he manages to build the nice aircraft that he does. The two part fuselage joined with a little piece of wire worries me and also how do you malange to get it all straight with out any gaps! I battle enough just trying to make a decent hatch without gaps. I built Zenair 701 to try and get used to his methods and I modified it to my methods I am used to. I would use hardwood spars for the center section.

Well done Simon. Glad you are making progress. A long nose does affect the stability, when the Airbus 340 600 was introduced to South African Airways 25 years ago it had bunks for the cockpit crew to sleep in on the long haul flights and many complained of air sickness due to the oscillations and Airbus had to tweak the software to reduce this.

Some video of the float fly. The S6 has a laser 300 that is still new so we elected not to fly with the cowl on as it is only the 3rd flight of the S6. The Stick is all built up and light for its size and has a Magnum 80 FS, lots of fun. We have built 4 sizes of this sick and all fly well. //youtu.be/1GmJnUW4pE4?si=b1leLoBc0hhYces6

Byron and I had a great day on Saturday when we attended a float fly event. The Catalina had its first outing since being painted and flies very well but has poor water handling. Lucky it has plenty of power to get it onto step. The S6 was built over 25 years ago and was never flown as the builder said the wing loading was too high for the thin wing section. He came out to see it fly and could not believe just how good it is in the air.

A tail heavy aircraft will show that it is very hard to trim in pitch and will tend to climb or dive. When I was testing the electric motors on the big stick the 50cc motor used 12 5000mah cells and the 30cc used 8 3800mah cells so there was a big difference in the cg and as the motors were changed at the field it was a good way to see the effect of CG on flight performance. As the airframe is very stable and been flown a lot it was not a worry. The lighter 30 cc set up showed that almost no down was needed in the roll when inverted and on landing it was not as stable on the approach as it tended to want to pitch up. Trimming the elevator was not a cure as it was clearly a tail heavy situation. This tail heavy tendency is not what you want on a heavy warbird when test flying as a pitch up at low speed will lead to disaster or a very shaken pilot. Dual Rates are very important in my opinion as you might need far less movement than what you expect but nice to have control if needed.

David Boddington wrote this in AMI August 1996

It is very easy to over complicate this discussion. My son and I normally test fly our models in Primer and once happy with the flight performance we paint the aircraft. It can be surprising to see how just the weight of the paint can affect the flight performance. Another example is if you fly at sea level and then fly the same aircraft at a higher altitude airfield. Many of the scale competitors at the world champs in held in South Africa were surprised at the difference in performance or lack of it, Thinner air is effectively the equivalent of a heavier aircraft.

A big difference between a scale aircraft with a higher wing loading than non scale lightly loaded aircraft. Scale or semi - scale aircraft normally have smaller tail surfaces and tapered wings which also has a bearing on the stability.

Take 2 airframes, 1 heavy and 1 light and you will see the difference in stability. I once did a kit review for David Boddington and when I had issues with the flight performance of the aircraft which was heavy and then compounded by our thinner air in Johannesburg, David said I should move the CG forward of the recommended position and it did help the flight characteristics. I have done this ever since and had good results. CG is also a personal preference as some pilots do like a twitchy airframe and others do not. Stability at low speed quickly shows if the CG is correct.

The heavier the airframe the less stable the aircraft will be so a more forward CG will be required. Always hard to put more weight in a heavy airframe. Elevator movement is critical as too much can result in a snap roll. EXPO can work against you on a test flight if the trims are out and you need to say up before trimming. I have always found it best to fly the aircraft to see how it handles as some aircraft can handle excesses better than others. Tomorrow we will be flying a 1/4 scale S6 that the builder never flew as he thought it was too heavy and would not fly. It flew very well when Byron test flew it and the original builder will be with us to see how well it actually flies.