Martin Harris - Moderator

Popular wisdom is that in order to reduce peak detection errors, you should charge at at least 0.5 C but it does seem that trickle charging at 0.1C may eventually cause damage. NiCd cells were so much easier to manage...

You misspelt the very common misspelling of lightning - so often written as lightening, and where no additional holes are involved.

My limited understanding is that they are physically/chemically different from “standard” NiMH cells, resulting in low self discharge but with a higher internal resistance resulting in lower performance at higher discharge rates. it’s a design characteristic rather than a quality issue.

A couple of posts removed as they are no longer relevant due to closure of this thread.

I’m not sure that this is the case - and such a policy would spell disaster for our club. Our site is within controlled airspace but well away from the extended centreline of the local airport’s runway and has operated 7 - 25kg models with permission both directly from the CAA and via the BMFA for many years. (The club pre-dates the airport by 3 years and has operated from a number of sites within the local area/airspace before purchasing our present site over 40 years ago)

It's a long time since I felt the need to use my tacho but it seems my recollection of needing a fluorescent lamp were a bit hazier than the light source! After digging my "Teamline" branded Min-Tach and a long search for an incandescent lamp (found one in the microwave!) it shows a consistent 3000 rpm with occasional drops to 2970 rpm (the same results as with a fluorescent tube) so I have to agree that modelling tachos can sense the minute filament cooling variations. At an approximate 1% variation in mains frequency, this seems outside Chris's specs but I don't know the minimum display increment or accuracy of the very cheap hobby equipment - maybe even some induced error through hand movement?

Welcome to the forum Steve. Hopefully someone can help, although it's a rather old kit and hasn't been discussed for many years on this forum.

I trust you're referring to her personality and conversational ability?

I think it's more basic than that. An incandescent lamp running on AC cools so little during each cycle that it's undetectable with any (affordable) light sensing device whereas an old fashioned magnetic ballast flourescent fitting produces rapid on-off pulses of light. More modern electronic ballasts work at such a high frequency that even if if they were detectable, they would be outside the normal range of a tachometer designed for model engines.

Welcome to the forum. To me, these look rather like promotional models that used to be issued to travel agents to adorn their shops.

An innocent explanation may well be that someone has googled for an obscure subject and happened upon this forum. The alarm bells in this case were 3 different posts on old threads arriving within an hour.

There have been several posts within the last hour or so from new members with a common theme of being replies to long dormant threads with no form of introduction. This might be a sign that they are AI bot generated spam. This may well be coincidence but perhaps these new contributors might like to post a short introduction in order to validate themselves as genuine modellers so that we can publish their posts and welcome them to the forum.

Welcome to the forum. Feel free to introduce yourself! Do be aware that we have heard of scammers preying on forum members so beware of “My friend has one for sale” and similar responses, particularly from responders with low or non-existent post counts.

That reminds me...

I like to have a tinker with old vehicles. I've been the registered keeper of this Triumph Terrier since buying it in 1971 at the age of 16 although it spent a few years in the possession of a friend. I finished restoring it around the Millenium and take it out for some exercise on the odd fine day. There is one major failing in my restoration - despite adding oil in all the right places, there's no evidence of it oozing out, as is traditional! I stripped my Series One Land-Rover to the chassis to repair and refinish it, rebuilt the very rotten bulkhead and overhauled all the running gear, putting it back on the road 3 years ago. I've owned it since 1979 when gliding gave me the excuse to buy it, but back in the eighties started stripping the paint while in daily use - well before the current fashion for keeping patination, so I'm still in the dilemma of deciding whether to preserve what's left or give it a shiny (well, semi gloss) new coat. My peers in the S1 club seem to favour the former. Contents unpacked, including my 1/4 scale Cub...the 1/4 scale Christen Eagle's wings were left at the club (deliberately) the previous day. I also bought back the Honda 175 that I bought new at the end of 1972 which had done the rounds of several friends since I upgraded to a 1968 Triumph Bonneville (along with the '69 model, the best of the classic Bonnies in my opinion). It has been kept on the road pretty much continually since new and I enjoy putting a few more miles on it each year. Sadly, the light fingered brigade relieved me of the Bonneville and due to police incompetence and inertia, I eventually recovered just the frame, seat and back wheel/mudguard.

These gentlemen popped in to advise on cockpit ergonomics during the build phase of my RCM&E Nijhuis Mosquito some years ago. ...and here's a recent 3D print to rectify the omission of a pilot in the V3 Durafly Vampire. The lack of a pilot in a scale(ish) model is one of my pet hates. Although he did react rather badly after the ground suddenly jumped up during a low pass in rather challenging conditions - happily, he regained his composure and flew the rebuilt model a couple of days later.

Tip for removing broken wing bolts. Heat an old/cheap screwdriver until it’s hot enough to melt a slot into the broken shaft. Then unscrew the stub with it once it’s cooled down.

I’m still not convinced that this is the case and can’t find any obvious supporting information on a brief internet search but perhaps the tube was constructed differently e.g. using different strand orientation if it was a composite? However, I’d be interested to see some details of this theory if anyone has a link to a copy of the Prof. Fry programme? Update: I’ve found the video on iPlayer (https://www.bbc.co.uk/iplayer/episode/m0029ktc/the-secret-genius-of-modern-life-series-3-3-rollercoaster at @ 9 minutes) and her words are “let’s see what happens when I run the same experiment using the same amount of steel, only this time my steel rod is hollow”.

OT posts moved to

Personally, I can’t see any reason to dispute that contra rotating engines/motors will reduce the various effects on swing. What causes swing? Primarily torque, propeller helix, gyroscopic precession and P factor. All of these are reversed with the opposite rotation engine. Surely, these effects cancel each other out?

Some slightly off topic discussion created from another thread…

Word of warning Geoff, but if you’re now becoming the main (only) driver, you might want to consider putting the insurance into your own name. While a reputable insurance company might take a lenient view in your circumstances, this is, technically, what is known as fronting and your insurer would be within its rights to refuse to pay a claim (with dire consequences for your future insurance dealings) should the worst happen.

I’m not sure that the 2.4GHz link is the weak point. The reported problems were concerning corruption of the stored programming. Re. the distraction factor, it does seem a likely scenario but with the less robust nature of simple single frequency FM systems, the proximity of a strong signal - especially during the call Establishment phase, seems a valid possibility.

As I recall, there was a known problem affecting the programming on certain Multiplex transmitters.

I'm assuming that's on a strength to weight ratio? I'm sure a suitable tube of increased diameter would be far stiffer on that basis although if it's very thin walled then it might be prone to buckling at any weakness in the material or damage. The central part of a solid rod doesn't contribute much to its stiffness so might as well be "removed". I know that some highly stressed aircraft used nested steel tubes for spar booms so there might be some added benefit from the inner wall component of tubing? I suppose that decision might also have something to do with ease of tapering the spar towards the tips?