Andy Stephenson

I changed the springs on a 150 and if I remember correctly the rocker pivot has to be removed to lift the rockers clear of the valve stems. The tricky bit is to remove the collets without losing them, it's best to order a few spares along with the new springs. Also, there are spacers on the pivot bar which are awkward to get back into position when putting it all back together.

Time to start experimenting, then!

The problem with working out which pins are inputs or outputs is that a microcontroller can have pins which can be programmed to be either. If applying power it may be advisable to put a current limiting resistor in the signal line to prevent accidentally powering an output.

The 4 unused pads on the board are for in-circuit programming of the microcontroller chip during the manufacturing process. That's why they are not exposed to the user.

Before Ripmax took over Futaba servicing of R/C gear from Model Avionics, you could buy these grommets as a standard item from them. Perhaps the Ripmax service team have them.

This was recommended to me, the prices are really good... https://www.mdpsupplies.co.uk/gloss-sign-vinyl

There are moulds available to create a really neat hot glue strain relief... https://www.t9hobbysport.com/winkler-multiplex-plug-mould-tool There are also 3d printed versions available.

The question is, have you tried it on a receiver? It's still possible that the signal from a servo tester isn't either strong enough or giving the correct signal thresholds to match the "bad" servo.

It looks like the signal from the receiver isn't powerful enough to operate both servos together. The "good" one probably has a lower threshold signal voltage so it works OK when both are connected but the "bad" one will only operate on its own when no other servos are helping to pull the signal down. Try connecting them to different receiver output channels, If this is not possible you will need a signal booster.

Modelfixings also have BA grub screws in stainless or 14.9 with 3 different end types. https://www.modelfixings.co.uk/stainless_grub_screws.htm Also Orings https://www.modelfixings.co.uk/o_rings.htm

What's the fire extinguisher propelled by, CO2 by any chance?

I built the RCM&E 27MHz FM set for 1/12 car racing, using SLM supplied parts, in the 80s because I was fed up with the interference that was endemic at these meetings. It had the new-fangled VMOS output transistor.

It looks like an Acro Wot wing, although Chris Foss may have used the same one for the Wot 4 Mk3.

People used to buy those because of the nostalgia of owning a diesel. Someone in our club bought one but had it converted back to glow because of the high compression causing a loud knocking sound.

I remember SLM in Cheltenham, They seemed a little irritated when I turned up unannounced to buy bits, although they always obliged. Those were the days when every man and his dog were making 27MHz radio sets and they had plenty of customers for the necessary hardware, cases and servo parts etc.

Changing connectors on a live battery needs to be done very carefully to prevent a short-circuit. Cut or de-solder only one lead at a time and complete the joint to the new connector, making sure to insulate it from touching the second one when attaching it to the new connector. Also remember to thread on the back cover onto the wire if fitting one.

I needed a really small receiver for 35MHz but the only one I could find was on 40MHz one, so I converted it to 35MHz simply by using a 35MHz crystal, no retuning necessary. I passed the range test no problem.

Strip ailerons that reach all the way to the wing tip are also liable to flutter due to tip turbulence. This why you will see some designs where the wing tip extends back beyond the aileron.

I've seen some engines that won't run at all if the slow running needle is screwed too far in. No matter where the main needle is set.

The first time I had flutter was on the ailerons of a Frank Vandenburg Vertigo. The plan said to fit 12gauge aileron torque rods. The plane landed but with a stripped servo gear. The torque rods were pulled out and 10 gauge ones fitted and that cured the problem.

Toto, Seeing as the servos have metal output shafts, It's almost certainly an M3 screw you need to fix the servo arm.

I've tried flashing Ni-Cd batteries in the past and it has never given me satisfactory results. I haven't tried it with Ni-MH but I wouldn't expect it to do any good either.

Once you have removed the aluminium housing, the spring needs to be compressed away from the positive end of the cell to unsolder it. I used clamping forceps to hold the wire. To reattach it to a new cell, the positive end of the new cell will need to be tinned first so the wire can easily be soldered. Some force may be required to fit the cell back into the housing. Be careful not to cut through the insulation of the wire.

1200 Wh/kg is impressive for a rechargeable battery but they don't state the power density i.e. the C rate which is the determining factor for the hobby. By comparison methanol is 6400 Wh/kg.

Instead of trying to make soldering bits, I would recommend adapting a good quality bit to your cheap soldering iron, this way you will at least get some quality soldering time before it corrodes. Always use a proper soldering sponge to wipe the bit. Don't use an ordinary bath sponge as it will melt and make a mess.