Andy J

will check fail.

Dug the battery out today just to check what is was and it is indeed a 4 cell 2500mah pack. Turned on the power and telemetry read 5.3V fore the battery volts which fell to 5.1v as I put resistance on the elevator servo arm. Found it impossible to stop the servo moving so don't think it is a dodgy servo or voltage issue.

Thanks for the comments / queries. May have been confused regrading the battery voltage as it is possible that the battery is a 4.8V pack. Don't think I can dig it out of the model to verify as this will require major surgery. The loss of telemetry at time 13:24:34 (and battery volts) is simply because I turned the Tx off and went to collect the model. As can be seen at 13:40:03 the telemetry recovers when I switch the Tx back on to check if the elevator still functioned which it did. What is strange to me is what would have forced a stable high wing design into a vertical dive. Do notice that at 13:34:06 the battery volts are dropping as the elevator demands go towards full up and then recover as the model hits the earth at 13:34:11 and the elevator demand is removed when I realise all further control is in vain. Don't use a switch on this model as I simply just plug the battery into a floating servo lead connected to the Rx.

Mike Tx is 2.3.14-otx RF SW driver was upgraded when using the FRSKy OS to get rid of the un-commanded servo issues.

Looking for an armchair detective to suggest a possible reason for a loss of control which occurred yesterday. Model was an old school, high wing 3 channel Playboy with an ~90inch poly dihedral wing. Model was powered by an OS30 2 stroke and it had flown previously without incident about a week ago. Radio, FRSky Horus X10S with OpenTx software, 6 channel Rx fed from a 6v nimh battery connected directly to the Rx. Battery had been fully charged approx 1hr prior to the flight. So once in the air on its first flight of the afternoon the model was happily stooging around at approx 100ft at no great distance from the Tx for several minutes. Rudder was slightly twitchy but otherwise the model was fully under control. Then without warning the model twitched and then immediately entered a vertical dive. At this point the throttle was closed and full up elevator was applied which appeared to have zero effect. After impact with mother earth I turned off the Tx and recovered the model. Model was implanted in soft earth in a vertical orientation such that the motor was fully buried. Surprisingly the fuselage suffered little damage although the undercarriage was torn off and the prop blades shattered. The wing which where adjacent to the impact point had suffered the most damage with the outer dihedral ribs on both sides having disintegrated which allowed the TE joint to also fail. LE and main spar joints appeared largely intact. On recovery back at the car the TX was again switched on and certainly the elevator functioned correctly. Did have my mobile phone in my trouser pocket and the Tx antenna was I think in a horizontal attitude. So can anyone explain what may have caused this lack of control and what could have been the reason for a vertical dive? Attached is the telemetry log to see if anyone can spot any anomalous behaviour. Crash occurred at or around 34:23. Playboy-2023-02-14.csv

Thanks for the tips ED, currently using Aspen fuel and I certainly find the engine runs far better on it than petrol and has less residue emitted out of the exhaust. Prop is wooden, think it was purchased from HK, so probably not the best quality. Certainly the prop throwing issue has occurred every time I have ran the engine, so did ponder briefly today if I could drill the crank shaft prop driver to accept a couple of M3 bolts. Did find the engine has less vibration now that I have fitted an NGK plug so that was positive item of advice from another thread specific to the engine. Sure I already have a spare carb kit so will do that change as the engine has certainly sat for at least two of three years since I last played with it. Despite not quite scale like for a TM, will get a spinner on order tonight to allow a better interface to the starter.

Yes did see those from JE but I am a bit wary about using a single nut to retain the prop as the GF-38 has a tendency to keep shedding the prop when it backfires. Certainly did it once yesterday but I hope this will reduce as the engine gets ran in and loosens up.

Did start using hand starting but given the reluctance for the engine to fire had too resort to using the starter. At least I got the engine running but the starter cone is not going to last long. Have charged up the ignition battery so perhaps it will be more eager to fire on the next outing. Will look again at using a small spinner to provide a better interface to the starter.

The rubber insert on both starters are fitted such that the small hole is facing forward. Turning the cone around would not help as the cone is then designed to interface with a spinner, which as I say is not fitted.

Not usung a spinner John. Currently all that engages with the starter is a standard engine shaft locking nut. Have looked at what the full size aircraft uses and perhaps a JEN domed nut from JE would semi replicate it but don't think it would be any better interface to the starter cone.

Well I got to the stage of doing an engine run today which brings up a couple of further queries. Have two starters both powered from a 11.2V lipo. The smaller one turns the engine over fine but the soft rubber cone is already starting to fret away whilst the second larger starter which is geared fails to turn the engine over as the hard rubber cone does not bite sufficiently onto the engine shaft nut. Is there any solution to this issue to allow me to use the larger geared starter. Second issue is after the first start I found that as I increased the throttle the revs dropped so I assume this would be caused by a lean mixture. Hence I turned the fast jet anti clockwise. This improved the top end performance but a rapid change of throttle is causing the engine to cut. So do I lean or increase the mixture to fix this issue?

Has anyone else tried Regen50?

Ron, what method do you use to convert pdf plans into Gcode files? Currently I use Inkscape to display the pdf then trace over the item to be cut using the Bezier trace tool. Once I have a rough shape I then nudge the resulting closed loop into the required outline using the Edit path by nodes tool. Then the required shape is converted into a line path which can then be converted into Gcode using the inbuilt J Tech photonics extension. All this take considerable time so would appreciate if a faster method of scanning an outline can be used. As for the cutting software I currently use LaserGRBL which has a very simple interface to the cutter.

Well its certainly good enough to use on my Tiger Moth Paul whatever colour people perceive it to be. Yet to verify it will survive being exposed to Petrol and exhaust fumes though.

Just to close off this thread I initially tried an Auto Extreme Chrome paint obtained off ebay at a very cheap price which was stated as petrol proof. Paint applied very well but was very prone to marking so was not happy with the finish obtained even after several coats. Was in Wilko's yesterday and picked up a can of Rustoleum Silver which was on sale for just over £8. Resulting finish on only one application coat is excellent with an almost sparkle looking surface so I will certainly be using that brand of paint again. Yet to try the Halfords gloss lacquer over the Rustoleum as the paint seems to be very slow drying so not out of the woods yet.

Very impressed by the quality of the covering. What technique do you use to cut out the compound curve trims?

Thanks all for the advice.

What is the difference of a touch up paint gun to a normal gun? Guessing it is something to do with the size of the gun paint pot.

Certainly the £100 budget has to cover the gun and the compressor.....or is this false economy as notice some two action guns are close to £100. So do I need a two action gun?

Don't have any compressor at the moment so imagined I would match it to go with the gun. Gun will be used for larger models wings etc rather than miniature detailing.

Thinking of purchasing an air brush for general use. Any recommendations as to what to buy with a budget of around £100. Happy to buy new or used.

Ron, how are you managing to cut Depron? I tried it some time ago but the white surface just reflected the laser light.

Just to close off this thread I have now tried using the weight measurement a couple of times for mixing Aerokote. Resulting mixture was far easier to apply than previous applications and has certainly resulted in a good finish on a small engine cowl I have been working on. On the negative side could not find any weight ratio mixing quantities on this product labeling. Also given I only needed a small amount of mixed product I did find dispensing only 1gr of the active accelerator difficult, so a couple of small pipettes would be useful to use in conjunction with measurement of weight.

Had seen your post Jim. How did you eventually proceed with fuel proofing it?

Do have some metallic adhesive covering which I purchased from Mick Reeves which I have used on the TM undercarriage support struts but is a right faff to apply so don't think I will be using that method.