Nigel R

Interesting enough. But. Maybe the thread title should be "FrSky Servo chatter"? Or "FrSky poor interference rejection"? Or "FrSky introduces noise to analogue outputs"? Or perhaps "fingers near servo stops chattering"?

Heat can be used to straighten out a warped bit of balsa - Heat, then clamping, opposite to the warp. Never really had a problem during covering though - maybe worth trying old style sanding sealer then dope instead of water based poly?

Another Nutball fan here - welcome aboard 🙂

There is the free online version of Word, too... https://www.microsoft.com/en-gb/microsoft-365/free-office-online-for-the-web Not used it myself. But. It exists.

Intermittent faults are the bane of an engineers life... just as true on the development side of things as it is repair...

Agreed. David, your CAD & 3d printing skills are making me green with envy. Nice hound too. Although he should be facing the camera 😄

Agreed, whilst the Acro Wot is popular it does have a few "characteristics" due to the coupling. The spiral bunt caught me on the few occasions I've had a go with a clubmates foamie.

Covering iron would be better if you have one. But if it's just a bit slack, that's probably not it. I was thinking of edges coming unstuck, that kind of thing. Stall strip can be quite temporary, you could attach something with some covering film to try it out for a flight or two.

If it's on the very edge of stalling out then a slight imbalance could tip things one way rather than the other. Can't see a minor difference like you report being the real root of the problem though. Seems like a lot has now been checked over. Couple of further thoughts: has there been any previous crash damage / repair? (possibly the structure is weaker on one side after repairs) covering - no loose stuff? maybe a last resort - you could try adding a stall strip to the root of the LE, this could (at least) get you a consistent "dead ahead" stall behaviour.

No inertia in a foamie, as noted, probably best "flying" it round with a bit of throttle to get some air moving over the rudder. Would also check the thrustline. You might find it is a bit out and correcting it allows you to get the trim back in shape.

Non pumped surpass engines are not uncommon on eBay... Just keep an eye out for a 91. It'll probably cost less than os seem to charge for a while brand new carb, even if they bothered selling them for older engines.

65mg should be ok, I'd have thought.

I would double check incidences including thrust line and then trim the CG with the usual aerobatic checks, at the very least with the dive test. Another point, this is an airframe with really big surfaces; what servos are you using? They need to be up to the job of holding those large surfaces in check. Simon and Martin's lists are excellent suggestions too. Lots of sharp changes of direction evident in this manufacturer's video, with no evidence of wing drop - your airframe should be "fixable":

Precision Aerobatics made good airframes. The stall should be quick, clean, but straight ahead in this kind of shindig. Perhaps it is a bit of a Friday afternoon one, or it has warped a little with time. Well worth checking out that everything is put together accurately. A Parachute involves vertical dive, hard up, then carry on downward in a deep stall. Are you doing that, or just pulling hard up to recover from a dive into straight & level? If it's the second, with this kind of airframe you may have to "fly" it through the recovery.

Surely, surely, if the prop was balanced, there would be no vibration? At least from the prop. Perhaps something else let go? I'm with Dickw. I have many IC props. Would use them any time on an electric. They're just props that exceed the required safety margin by more than their electric counterparts. I can't materially see them being less efficient, maybe someone can explain why that would be the case?

Not sure how the UK will benefit?

Same camshaft across the board, I thought? Common to 40, 40 surpass, 52, 56a, 70, 91, 72a and 81a from memory. Same part number etc. Rcjapan sourced one last time I was in need. I bought a 56a with very pitted cam. Cam chest design seems a slight weak point with the bearing that is difficult to replace etc.

"Ulterior Motive" 😄 Be interested to see what you find with the linears. Not heard of the Loening before. Looks a lot like an early Grumman. Don't know if you've seen this thread: https://www.rcgroups.com/forums/showthread.php?2887837-Build-your-own-Grumman-style-retract-system Definitely a project in its own right!

They're very expensive. Beyond that I know nothing. Mighty Barnstormer is pretty big. I'd be amazed if a standard servo can't be hidden inside the wing. Your pinch point will be the control horn either way.

I realise it sounds "clever", but, empty the tank..! That said. There would maybe be a fl oz or two in the system at most, easily absorbed by an old t shirts or towel or whatever, wrapped around the nose. Yes, rubber or plastic boot liner to put everything on.

I concur. Only an absolute moron would believe that someone would use a six foot model airplane purely to display a swastika for political purposes.

Didn't know you were Montpellier way. Nice neck of the woods. Spent a number of summer holidays in Tourbes and Plaissan, the outlaws used to have a small place in both villages (well, they swapped from Plaissan to Tourbes). Happy days. Sorry for going OT.

Weston have certainly had value on their side for a long time. Happy customer here. £20 for the 5% Laser mix from Southern Modelcraft looks pretty good, too. Always used to use SMC way back when, as the club I was in did a bulk buy.

IME, it's normally about as simple as shoving the lipo as far forward as possible, up against the old firewall. I've not yet had a model that won't balance like this. But. If needed, you can build a box on to the firewall to mount the electric motor (you're probably doing this anyway, unless using threaded standoffs) hack a hole in the old IC firewall; poke the lipo forward, through the hole, into the motor mount box. The lipo is a heavy component so moving it around makes a big difference to CG.

For sport flying it neither helps nor hinders, really. Lower nitro is a bit cheaper. As Jon H notes, exceptions do exist.