Engine Doctor

I used to buy my batteries from 7dayshop.com but when Covid struck the supply chain fell down and they no longer list them. I still hsve some left so ok for a while. I have some of their AA cells made into Tx pack probably 8 or nine years old and some AAA packs in models a few years old and working fine giving good voltage etc under load . Never been a fan of Vapextech cells . I bought some when they first appeared and they didnt last very well. What to use when my stock is used up ?

With Nimh cells i have found that anything above 2000mah capacity are more prone to failure and drop their voltage drastically under load as IR increases. I lost a good model sone time ago when a cell in a 6v 2700mah pack packed up. When checked the pack showed 6.3 v but as soon as any load was put on it the voltage dropped to zero ! Just one cell cost a lot of grief .Up to 2000 mah they seem fine. I now only use the ready charged or LSD type as they seem even more robust than the standard type.

Southern model craft used to sell a ltr for less than that ! Luckily i stocked before Dave retired. The new owners have gone quiet but were supposed to be keeping the name going. Fingers crossed.

Every two years ? Really. I ran a Saito 45 for five years on one set and a ys 63 for longer with no bproblems . All my fuel is synthetic based , never use castor except in old engines and diesels with iron pistons / liners.

Look for Sellotape Diamond tape if you can find any otherwise their Superclear tape 8s the currdnt nearest. Very strong adhesive, UV resistant and once on its unoticable as its so clear. The Scotch tape super clear is not very good.

All goo Good tips add up and " Many an ickle makes a muckle"

Once your happy with running the engine and want to add colour to the cylinder fins have try at Anodising. Pic below is a crankcase I made for my Boddo Mills. If you fo try anodising then start with blue or red dyes as greens yellows are notoriously tricky to get right.

Hi Andy. Welcome back to the world of IC power. Dont turn down a Enya 4C if one turns up. They are in the same class as Saito and OS for quality of materials and reliability. Spares may be an issue now but generally they last and last and are very strong. You could also consider a smaller laser . Jon knows everything there is to know about them and can advise. Re laying up for winter . Corrosion will be your enemy. On the last run of the year, run the engine out of fuel while its GOOD AND HOT after flight and make sure its not running rich . Doing this will help evaporate any methanol thats got into the crankcase . Then as soon as you can give the engine a good dose of oil. In the cylinder, through the crankcase breather and inside the tappet cover etc. Dont use any fuel or oil that contains castor oil or 3in1 oil as it set like varnish . Over the years ive tried many different oils for storage and found air tool oil to be very good for this as its designed to protect air tools from any moisture in the air that powers them. Any used engine can be a risk . With four strokes beware of any of the chinese clones that have little or no compression. Check this with a fully open throttle; very low or non existant compression idicates a manufacturing defect and is only fixable by fitting a new head. Also check the thread where the exhuast fits into the head . This applies to any engine with a screw in exhaust. A worn thread means a new cyl head ! Look for any nuts that have been chewed with pliers or wrong size spanners a sign of a careless owner. Lastly remove the glowplug and check thread is ok. I was caught out by that many years ago with an open rocker Enya I bought that had the glowplug glued in ! Spares like castings and specialised parts for all Chinese clones are virtually imposible to find new and parts for current OS or Saito or YS engines are very expensive. Bearings if a bit loose or noisy are easily available for virtually any fs engine and not expensive and available from any good bearing supplier. Never be afraid of asking about engines on this forum , no question is a silly question . If your a member of a club beware of unsolisited help from the " Club Expert " look for any advice needed from an IC flyer who doesnt constantly fiddle with his engine and has consistent flights . Good luck and enjoy the sound

Hi EGB. The weston silencers or pipes are tuned for outright performance or throttle responce and are verh good . Your os silencer mising part is likely the same size as those fitted to many chinese clones like ASP, SC etc. There are loads about secondhand have alook on ebay and check mounting hole centers. Also measure the inside diameter of the exhaust you have and you may a used end cone and through bolt on here .

Any car bulb 12 or 24 will do doesnt have to be a headlamp bulb . Indicator bulbs work fine and we usually have those lying around . I used to just dunk them into a bucket of salty water overnight but was told that it leaches lithium into the water and that has its own issues with disposal; but it does completely discharge them .

Another possibility is that the bores in the conrod are not parallel. This can easily be checked by fitting a drill shank or some metal rod of appropriate size in both the big and little end journals and check for parallel. Easier to check this first .

If your crank case is not square suggest re facing the surface and then cut a shim for base to correct the height of cylinder. If case is ok check cylinder base for square.

I have just looked at the Spectre 1950 engine test for the DC Wildcat , a 5cc longstroke engine , not unlike your engine. The test was done by L. H. Sparey for Aeromodeller in the April 1950 edition. The recommended prop for that is 13 x 6 . It might spin a 15 x 6 when its run in but its a bit of an ask and unlikely to be of any real advantage for thrust . As Jon says start off with a lighter load . Once running and up to temp stop it and allow to cool a few times. If at any time it starts to overheat and labour stop it and allow it to cooI completely then start again .It should start to loosen up after a few stop start cycles. Gradually increase speed and adjust comp and fuel for max revs. Once it can hold its rpm without overheating or labouring then try experimenting with props. The Wildcat tested said that it would spin a 13 x6 at between 9k an 10 k rpm but that was a Mk 3 so DC had done some homework to get there.

Carbon tetrachloride, now that is a dangerous stuff. Used mainly in small pump action fire extinguishers found in cars and lorriesof the day. Its use was banned in these extinguishes due to it releasing phosgene and free carbon if it hit red heat metal . We were taught this in the Fire Brigade and to be very careful with its use on small car fires. It was easily obtainable and used as you say for degreasing. Plating companies used tanks of it to degrease bits . We even used it to thin paint for spraying ! Then it was discovered how dangerous it was and caused liver disease .

I use a marker pen to mark the magnet poles that attract . Nothing worse than glueing them in and finding they oppose one another😶. Ive recently started using Toolstations thick grade cyano for fixing smaller magnets. It seems to set very tough and not brittle like some brands and has high solids plus a 50g bottle is under £5.

Potters at their 5 Lakes site in Essex would be a good place to ask. They have a very large site with a golf course and a long pitch and put plus lots of other open areas. Its also a long way from the nearest town.

Just my view but I liken those in our hobby that denegrate the ic models as similar in outlook to those who have moved to EV's. They moan about the cost of fuel, tax etc . Shortly after they appear at the field in a new EV having spent thousands of £'s to save a few £'s when their previous car was perfectly ok and in many cases not that old ! A few pounds on fuel and tax is a tiny fraction of what they spent on the new overpriced low range and probably lower quality car and the soon to be introduced tax system and the high cost of public charging. They ovbviously didnt go to school on arithmatic day 😊. Similar story with ic models, unhappy with the cost of fuel , the noise and poĺution etc. Next week turn up with a new electric ARTF with a new batch of expensive batteries costing hundreds of £'s and transported half way round the world with associated tons of pollution ! Just admit it that most of these so called green warriors just want the latest model ,number plate and for the moment free tax or new model.....why? Because they can. If they really cared about pollution then they would use their existing cars and models until they wear out then change. Its all part of our " must have now " culture. Will I go all electric inc EV? No not until I NEED a replacement and if I'm still around perhaps all the lies and hype around electric power just might have died down. Long live IC power.

Never had an issue .

I have used cellulose for cleaning plastic film covering for many years with no issues or detriment to covering from Solarfilm or any of the polyester shrink films. The exception is Solartex where it can attack the proofing layer.

No CAA ID then ?

As EvilC57 says IPA or nail varnish remover , acetone or cellulose thinners wil quickly remove the smears .White spirit is unlikely to remove it . The smear is just the adhesive and happens all the time . Just finish covering and have clean up session. Some coverings are more prone to this than others. Our local model shop sell Chinese covering and its brilliant , shrinks well , stays tight and unlike some branded mid price range covering isnt see through.

The MG90 s would be fine . Its a small plane and even the cheaper sg 9g would be ok . I used the plastic geared 9g in a very fast Nigel Hawes Tucano and flew it regularly for 8 or nine years with no issues . There is a lot of servo snobbery and in a lot of cases all it does is push the price up . There must be millions of the little Tower pro in circulation without issue but its down to you really . Emax are very good so its your call .

Loads of cheap 9g or smaller servos about . I have used tower pro 9g and have only ever had one duff one found during test before fitting, The metal geared type although a touch heavier are more durable against knocks. Fine for small lightweight models

The last cast iron rod/bar I bought i found on Ebay, Mehanite grade. Also good for making new piston for old diesel engines. Previous to that I have used some old cast iron window sash weights. Failing that have a word with a GC piston rings Gavin might supply some. I forgot to say. Try to find the smallest dia bar as its often difficult to find anything smaller than 30mm and thats a of waistage and time spent getting down to size.

Modern parlance " its just business, nothing personnel". As a modelling community we were lucky the brand didnt ceace production when Niel retired some years ago. I hope you all get the modified parts for you inlines and get thdm in the air. Jon's position is just another example of collateral damage in the closure of the factory who it appears only mades Lasers as a side line. RIP LASER ENGINES