Nigel R

I wouldn't suggest spruce for crash resistance - "no such animal". Spruce is simply a consistent wood. If you're happy that you have good hard balsa spars then just use them. If you're not happy grading them or you bought a kit and the supplied spars are soggy soft, then replace them.

Super 60s have a fairly lightweight structure to start with. Lots of air, occasionally punctuated by balsa sticks. I note the Colin Usher redraw of the plan shows 2 dihedral braces per spar, for a total of 8 braces: https://outerzone.co.uk/plan_details.asp?ID=4059 This would be plenty strong, I think. Whereas the Ben Buckle version has fewer braces. 5, according to: https://outerzone.co.uk/plan_details.asp?ID=552 As a quick fix in this area only, I would either do what Piers suggests, and put a full depth brace at the front, or add the extra braces at the rear. (mind you, I'd probably not build the thing that much like the plan in any number of places, I'm more of a fan of D-box wings and slab sided fuselage construction)

Running an incandescent bulb at half its rated voltage results in something like 40% of full power, IIRC. You would need to measure the bulb with a multimeter to get an accurate figure though.

but how do you get the new servo in?

Question to you Andy I've rejoined via usual club membership, the club put my CAA reg through via BMFA. I can see my CAA expiry is in around 11 months time. However. CAA have just emailed to tell me my operator ID has expired. Do I need to worry about this?

Balsa is fine but you need the right grade (i.e. rock hard). If you build from a kit, you might get something soft and soggy instead of the hard grade that you need. Whereas, spruce is a safe choice. I had a Junior 60 (the predecessor) for ages, with a small four stroke in. It had much the same construction (which always made me a touch nervous in tight loops) it had more flights than I can remember and was then passed on to several further owners after me.

'feed of oil back into crankcase'... The FL70 has a standard four stroke crank vent nipple - the special silencer just makes a way for you to route the occasional drop of oil straight out the exhaust. Could you get the same result by running a few inches of silicone tube out to where the exhaust outlet is? (happy to be corrected if I'm wrong about the vent being a standard thing)

Coming together fast!

Hence the general 400ft limit?

Minor point of note, use of commercial hobby drones in Ukraine decreased a while ago - Russia worked out they could use the manufacturer's own snooper systems to located both drone and operator, with obvious consequences. Commercial drones tend to rely on GPS which (to probably little surprise) can be jammed/spoofed.

Don't know if you've made a choice of motor yet, but that kind of size with a scale-ish Cap/Laser sort of fuselage suggests a 15cc four stroke would be nice if built light. A 20cc four stroke would put the wing loading up a bit, but would still work fine, I think, and probably what I'd go for. Wing area looks decent, so anything in region of 6.5lb to 8lb would be a nice flyer. Swept back wings make it look a bit like a Giles... and for direct comparison, this kit...

With the large ailerons/flaperons, you can program a "landing" mode (or mix, or whatever), and if you need to bring it down quick, you set it to raise the flaperons by some amount (15 deg or so) to dump lift. It'll need elevator trim. But this is very effective with fun fly types. Next fun fly I make, I might split the ailerons and program a crow mix.

Yes, just clamp the gear to the firewall, no steering, easy, simple, quick. If you must have steering then run it from existing rudder servo no need for extra one.

I fly off grass, and most of my airframes are trikes. If it's currently set up as trike, I certainly wouldn't say it "needs" changing. (I also wouldn't change it the other way either).

ED The discharge curves of nicad and nimh are nigh-on identical (at least all those I have seen). Nimh simply have more capacity. With the same load, a nimh would actually drop voltage slower than a comparable size/weight nicad. Graceful failure of 35MHz operation (in several ways) may have been "useful" but it was only a by-product of the nature of the (broadly) analogue design and not a deliberate feature - I'll take a configurable low volt (and poor signal strength) telemetry warning from modern 2.4GHz kit any day of the week. The less said about brown out and 2.4GHz the better, or someone will come along and mention Spektrum and that'll be the end of the thread 😆

Used Weston for number of years without problems but you never know, bad batch, some contaminant, etc I think JD8s suggestion is the best, try a ring in some of the suspect fuel as a test. If it's dodgy then dispose and replace the fuel, not much else you can't do I don't think.

Surpass, if you need a new one. But, What's wrong with the existing fl70?

Bandages work. Braces work. One or other might be easier for any given wing. Horses for courses.

Quite. Lipos are a lot cheaper than a car, or a garage, or a house, etc.

Lithium cells burn pretty darn good. Deformation / puffing indicates some gas has been released at some point. Might be low quality manufacture, might be damage. The batteries I have dealings with in professional capacity are lithium and the end user / manufacturer has zero tolerance for any has discharge or deformation. Make of that what you will.

Surely you mean Mon Dieu, non?

Yes, highest risk is when charging and immediately after. (Or when being abused via discharge)

Some lessons are hard learnt.

They're really good dBs though.

Stick with Eneloops, they are rated at a good few amps before any voltage drop occurs, plenty man enough for a five servo 10cc glow model. YMMV, of course. Let us know how it works out if you do. I've not used A123 cells.