Peter Christy

Jonathan: I have an OS 20FS, and I ran it for years on Bekra 16% without issue. Its currently in storage awaiting a suitable model's turn on the building board, but I had a look at it recently, and its still in excellent condition. Bekra 10% should be absolutely fine. Heli fuels are generally intended to run in hot environments, such as found in helicopters - and 4-strokes! Jon (Laser) & MikeT: Bekra doesn't have any castor at all. It is pure synthetic, mostly Klotz Techniplate with a trace of EDL IIRC. It is "Super-Techniplate" that has castor. I have no idea what Optifuel are doing with it, but the original formulation definitely had no castor at all. If it had, I wouldn't be using it! Ben Godfrey (original owner of Bekra) who formulated it had a lot of experience with racing two-strokes, as he was heavily involved in the Yamaha motor-bike racing team many years back. Sadly, he's no longer with us to consult, but my son and I were involved in the testing of Bekra fuels during their development. The only change made to it from the original formulation was increasing the oil content from 15% to 18% because of OS's warranty conditions. All that did was make more mess........! And Ben HATED castor oil! 😉 -- Pete

I usually make sure I'm wearing bicycle clips for mine! 🤣 More seriously, as long as the airframe is reasonably true, the CofG is correct and the throws look about right, I've rarely found maiden flights an issue. Its all about preparation.

Also worth checking for a corroded earth connection. Starters draw a lot of current, so the tiniest bit of resistance anywhere will cause the volts to drop alarmingly at the point where they are needed. Check where the earth lead from the battery is connected to the chassis/engine/whatever. Clean with a wire brush, and apply some grease to prevent corrosion returning, before re-tightening. A common fault on the old bangers we used to run as students many years ago....! -- Pete

Hm! This sounds sort of familiar, but not quite! I have a UMX Pitts Special - always had a soft spot for Pitts' since I had a Cox .020 c/l one as a kid! I fly it using a JR DSX-9 Tx - my only dedicated DSM-2 transmitter. The first one flew beautifully for nearly a year. Then it suddenly started looping on take-off! A quick check revealed that not only had the elevator reversed itself, but so had the built in gyro stabiliser! I could reverse the elevator, but not the stabiliser, which led me to conclude it was either the servo or the stabiliser at fault. I returned it to Horizon, who didn't even acknowledge receipt of it for months, and were totally uncommunicative, until a brand new one suddenly turned up at my front door! The new one performed flawlessly, but I haven't flown it in a while! Must be very careful with the pre-flight checks next time I take it out....! -- Pete

I was clearing out the workshop this morning, and had an empty cardboard box ready to take some of the rubbish. Naturally, the cat immediately came in and sat in it - which reminded me of this:

Are you using a Spektrum transmitter, or one with a multi-protocol module?

Sent to me by my daughter! And yes, she is! 😆

The big issue seems to be distinguishing between conventional model aircraft and "drones". I have never understood this problem. Graham Lynn got it nearly right some years ago, as mentioned earlier in this thread. I'm sure I've said this before, but I'm going to repeat it here: "A traditional model aircraft is incapable of controlled flight outside of the pilot's LOS." Simple. Think about it. Free-flight is not controlled flight. Control-line: By definition, always in LOS of the pilot. Traditional RC model: Will be out of control if it leaves LOS. It may fly away, but then it becomes Free-flight anyway. Only "drones" can maintain controlled flight outside of LOS. Now what is difficult about that? -- Pete

Not sure if its the same manufacturer or not, but some years ago I had an AirForce 40-something heli engine (imported my MacGregors IIRC). It turned out to be a fine engine, once I discovered it did NOT like nitro! The instructions were vague, and not translated very well. It was made in Japan, so I assumed that - like most Japanese heli engines - it would like its nitro, and ran it on 16%! WRONG! It was very hot and spitty, and would not tick-over properly. I tried a tank of straight (NO nitro) in it, and it ran like a turbine! If the manufacturers specify 5%, then I would go with that, and no more! If it isn't happy, try it on straight. -- Pete

Yes, I actually did that once! I'd got a Wot-4 Foam-E as a hack for testing receivers. The original instructions gave the wrong position for the CG, making it VERY nose-heavy, as I quickly discovered as soon as it got in the air! Desperately stretching for the elevator trim, I found the on/off switch, with the inevitable results. Unfortunately, it was a modern transmitter, which takes a few seconds to boot up. It also refuses to transmit until the throttle is shut! By the time I'd got it sorted, the model had long buried itself in the unforgiving ground. At least the replacement fuselage came with a warning about the incorrect CG.... -- Pete