Christopher Wolfe

Inkjet printer refill bottles are pretty useful for small fuel tanks. Typical sizes are 25ml and 40ml and they even have a useful nozzle in the cap. The ones that I have tested are not affected by diesel or nitromethane glow fuel. Poke a vent hole with a small soldering iron, force (melt) a brass tube into the nozzle from the inside and bend for fuel pick-up. So the pick-up is fixed but then so is your Mills tank so no loss. * Chris *

I once purchased an OS FS-80 quite cheaply as it was a poor runner. It had not had much use (judging by the exhaust pipe colour), so after a clean and a gentle valve lap with jewellers rouge the culprit was discovered. Timing off by just one tooth. Fixed that, set the valve lash and it started with a few lazy flicks and ran sweetly. Previous owner must have 'fiddled' with it. * Chris *

I have mounted some u/c legs in a slightly wider than normal channel in the hardwood u/c block filled with Silastic silicone sealer with a couple of conventional straps added for security. Worked quite well for pylon racers. Press the legs in, wipe away excess with a plastic squeegee (credit card), add the straps and the job is done. Has always outlasted the models. Regards * Chris *

G'day Engine Doctor. So was it really chrome? My understanding is that OS cylinder bores were nickel plated and notorious for 'peeling', especially if run a bit lean. Regards * Chris *

As a keen fly fisherman I tie my own flies and thus have a few specialised materials to hand, so I tried this UV cure resin to attach a canopy to my Tru-line Tiger. Completely clear and cures in 15 seconds with a UV torch. A great result and it appears to be quite fuel proof against the exhaust residue of an OS Max 45 FSR running 5% nitromethane.

E.D. Whatever colour makes you happy. It won't affect the revs too much. It's only a Magnum so don't go overboard. Black anodising is good for cooling but any colour that takes your fancy should work; For the Viton rings consider adding a lock to the comp screw as the 'feel' is very soft for a model diesel engine. Chris

How to retrieve a model from a tree. 1. Throw a line over a branch (bow and de-pointed arrow works well) 2. Tie a cat to the line and haul cat into tree. 3. Phone the fire brigade to rescue cat from tree. 4. Say to the fire brigade cat rescue team "While you're up there"

Here is a short video that I found describing how to use tissue over laminating film. It really does increase the stiffness of an open structure quite a bit. It's also handy if trying to re-create a vintage look for old timer models. Actually, I use thinned nitrate dope instead of the varnish but the principle is the same. https://www.youtube.com/watch?v=3RMx1obWvc8 Chris

I shall ask the builder next time I see him at a comp. as it's a nice looking conversion and it ran very well. Most of my conversions are 'factory' ones mostly Enya's (SS 25BB DS, Ultra 11CX DS and a 41-4C diesel four stroke) Chris

The Cox Conquest .15 is a popular subject for conversion to a diesel here down under. It makes a decent engine for diesel team racing as it starts readily and has quite useful power. The 'Cossie' is a Cox Conquest with a Rossi .15 piston and liner (they go even harder) ?

Has anyone converted an older engine with a baffled piston like an Enya ? One could always retain the baffle and peg the contra-piston as OS did many years ago http://sceptreflight.com/Model Engine Tests/OS Max 15D.html Of course, one would have to mill a matching slot into the contra-piston. The main problem that I have found converting glow engines to diesel is determining whether the con-rod and the crankpin are up to the task and if the piston/liner fit are sufficient to give the required compression seal (I have yet to encounter a model diesel engine that uses piston rings) Chris

A similar product (possibly the same stuff) was sold here in Australia 20 years ago. I obtained the information from an aeromodelling friend who used to work for Tony Cincotta at Saturn Hobbies, his after school job was to cut the laminating film up and package it. My late friend, Brian Winch wrote a few notes about application so I have scanned and included his report in case it may be of use to people who are new to using laminating film. My only tip is to add holes in wing ribs to allow heated air to escape unless you are making balloons. Chris

Actually, it could be quite useful as an anchor for the model boat!

Not complaining about your repair work Allan, it's a much better looking solder joint than your first photos of the factory job. I was commenting about the soldering of the SMD components photographed below your repair, that looks like poor quality control. Blobby looking cold joints are scary to look at from an electronic reliability point of view. For example, I was taught (many years ago) that if one cannot inspect the solder joint down to the individual wires then the joint was suspect. This was not for moon missions but as it involved my fellow Australian RAAF mates it was vital to get one's soldering skills together. Near enough is not good enough!

With all due respect, the quality of the soldering of the SMD components appears to be a bit dodgy. The assembly robots require a bit of fine tuning as their solder joints are crap. Ex HRSI (High Reliability Soldering Instructor) trained to Nasa standards.

Lovely stuff. Our mortar tracking radar had a drum memory and also used magnetic amplifiers. The primitive computer took it's inputs from rotary encoders for bearing and elevation and from the radar for slant (actual) target range. From that, given that the system was accurately surveyed in and the antenna was precisely calibrated to a known bearing on a good day it could be fine tuned for surprising accuracy and could locate a mortar baseplate to within ± 30m at a range of 10km, sometimes before the mortar shell actually landed. With a quick counter battery response the area for 1 sq km in and around the location could be saturated with nasty air-burst projectiles. (Splintex) The computer was hard wired to calculate true range from the slant range and elevation data, X-Y map coordinates from the bearing and then integrate the results with gravity and air drag to obtain the parabola of the projectile. Then it was a matter of extending the parabola backwards to the launch area and observing the map. Model aircraft input: I discovered that a Phil Kraft Ugly Stick with a Taipan .61 was ideal to fine tune the optical telescope alignment to precisely the centre of the radar tracking beam at about 3 km. The radar locked on, the scope was aligned and so the tracking results matched the map and survey data. All in all, sad news for the bad guys. Yeah, my Lenovo tab is an Octo Core and it;s already 'obsolete' after just 4 years. Also, the actual moon landing was 52 years ago, showing my age, but it makes the achievement even more impressive for 1969!

Your mobile phone has probably 10,000's times processing power of these early Apollo computers. I used to work in the early 70's on weapon tracking radar systems, magnetic drum memory systems and TTL processing were the order of the day. What a sweet way to learn about digital electronics when I was young enough to actually understand it. Clock speed maybe 1MHz. So congratulations to the pioneers who actually had one chance to get the moonshot right 42 years ago with such 'primitive' resources.

Try Vegemite - It's yummy on toast! skippy

I use 38µ laminating film. Shrink and cover with tissue or silk, well damped, use an aerosol puffer filled with water and a couple of coats of 50% thinned nitrate dope. Tissue may be applied with random patterns as with a slight overlap it's just as good as a continuous covering. The film airproofs the structure and the tissue/silk adds tensile strength.Much stiffer than uncovered film. Works out lighter than tissue or silk alone and the dope does not run through silk and produce blobs. It dries quickly too. Remember to poke vent holes in wing ribs as shrinking the film can result in a hot air balloon. Check the film covered flying surfaces for warps and adjust with the hot air gun before doping on the covering as any warps are about to be locked in. One other bonus that I have discovered is that the covering seems to last for years compared to straight tissue or silk alone. skippy

Today I just checked and storage charged some 6S 5000 packs that are over 5 years old and seldom used. Stored in an ammo box (minus seals) at about 4°C in my workshop fridge the annual check (last one 19 Dec 2019) revealed that cell voltages were about 3.76V, down 0.04V from the original storage voltage of 3.80V over 12 months ago. Packs were allowed to warm to ambient temperature (about 28°C) for 24 hours before testing and balance charging to storage voltage of 3.80V per cell. Dunno if I should have even bothered as 3.76V per cell is adequate for storage IMHO. As with most chemical reactions, I believe that low temperatures slow them down, including the degradation of batteries. I decided to use the fridge as summer temperatures here can exceed 41°C skippy

What is the most dangerous question in the world, because it has no safe answer? . . "Honey, do I look fat in these jeans?". . . .

Posted by MattyB on 10/08/2020 16:44:15: Posted by Tony Callan on 10/08/2020 14:48:50: That came out a few months ago, ostensibly to correct a bug that caused very occasional uncommanded servo movements, but it seems they were more focussed on encrypting the protocol to try and force people to buy the new TXs and RXs than releasing solid RF firmware. Not only does that mean the new TXs won't bind to aftermarket FrSky compatibles, but lots of other bugs were introduced which they are now leaving to the community to squish for them. I know that this is a few months old, but is encrytping 'Open Source' software aganst the rules? I understand that dji got away with this years ago with their drone software. So are Chnese companies immune to copyright laws? Cloned engines are a typical example. skippy

This is one of my favourites Boeing 777 flying indoors Quite a stunning demonstration and should inspire the Depron fans. Skippy

Posted by Rich too on 08/01/2021 06:49:56: I have used silicon sealant successfully, it is easily removed if necessary. A big plus for that one Rich too. I have some models that are over 20 years old and the servos have been tacked onto epoxy glass and carbon fibre with no deterioration at all. I think that the slight flexibility helps absorb flight/landing stresses. Use 'neutral cure' silicon though, the stuff that smells like acetic acid is corrosive, especially to servo and Rx electronics. Just degrease all surfaces prior to bonding. Skippy

Here is a nice one from the cousins'