Engine Doctor
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Posts posted by Engine Doctor
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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.
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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.
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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.
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Never had an issue .
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On 29/03/2024 at 08:59, leccyflyer said:
As pointed out above, decent quality isoporopanol will remove those covering film adhesive marks and is relatively gentle. Good old fashioned purple methylated spirits would be my next port of call if the residue was particularly stubborn, moving on to white spirit. I'm constantly surprised at the frequent advice to use acetone, or even worse, cellulose thinners for such jobs. Personally those would be my absolute last resort solvents to let anywhere near a model which had any form of plastic covering.
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.
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7 hours ago, J D 8 said:
Out at early this morning to check on cows near calving which are in field next to house.
On the walk back came across a lost drone in the grass just some twenty yards from the house.
Put it on kitchen table and went to do something, came back after a few mins and it was flashing its lights like crazy.
I know very little about drones but guess it was hoping for a response from its controller. Pulled the batt as did not want it lifting off in the house [perhaps]
Only marking says MINI 3 on body and CINE Z908 max on rotor arms.
No CAA ID then ?
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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.
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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 .
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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
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3 hours ago, Paul De Tourtoulon said:
Any idea what sort and where I can get some metal for piston rings?, I would like to have a go at making one on my little Emco SL,,,
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.
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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
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Hi Martin . I have often wondered about C3 bearings for use in our engines. Designed to allow for heat generated especially at start up and the subsequent expansion that can cause bearing failure. I have never actually used them.
How do uou find them ? Is the extra clearance noticed in the feel of the engine? What types of engine do you fit them too? I can see a possible advantage on say a Ducted Fan Engine although they are pretty rare these days.
With the extra clearance do you choose the sealed type for external/front bearings etc ? How do they compare to standard clearance on our applications ?
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Good luck with that one John. I guess foam models were never intended to last so long. Another factor to take into account is the effect of UV on the foam. I kept a small foamy in the spare bedroom that I bought for my grandson. After a couple of years it lterally fell to peices like plastic bags do . Had the room had full sun then I would expect this but it never gets any sun ?
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I'ĺl check my bits box but might not be until after Easter weekend.
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Fingers crossed for your birthday 🤞
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Welcome back. Yes its changed a lot over the years but you will get all the help you need to get up to speed here on the forum.
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8 hours ago, John Minchell said:
All the above pre-supposes that the underlying structure is wood (balsa or ply). How do you get the glue and colour residue off if the model is a foam one? Because you can't use heat or thinners?
John M
Hi John . I bought a second hand edf model some years ago. It had been very badly painted with a sort of red lead coloured paint and looked dreadful . It had to com off. I used a mix of parcel tape and gaffer tape . It did alter the surface a little but still looks fine after a couple of light coats of polyester base coat that gave a satin finish. The trouble with foam is that any paint will creep between the cells of foam and cant be removed. EPP ( Expaded PolyPropelene) foam is ok and you can use various thinners and repaint in a colour that suits ( test a piece first ). As you say heat is out of the question with most foams as it ruins the surface . EPS (Expanded Polystyrene) is best left alone as its very easy to damage and melts at the slightest hint of any aggressive thinners like cellulose. It can be painted with artists acrylic , water based sprayed on neat . Finish off with Ronseal water based varnish again sprayed neat.
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Hi Hill climber. The ball bearing does not need to be the same diameter as the CP but dont use a tiny one as its likely to crack the CP. Cast iron is slightly maleable so a good tap often expands it and as its effectively being squashed in the middle it expands equally outwards a few microns but often enough to get a good friction fit.
When i make pistons i get them to a sliding fit up to the exhaust port. Then clean and test assemble with plenty of oil and if possible a prop fitted to assist turning the engine . This determines if it still to tight turn over or if it needs a bit more lapping . As soon as the piston passes the exhaust port it should start to compress the air and a bouncy resistance felt . The bounce might not be pronounced if its still tight but be careful if you do any more lapping at this stage as it easy to go tooo far and ruin the piston. Everyone will have their own method . Keep going and you will get there 👍
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I was just having a light hearted jibe . Its a quad flying in an orchard so not really interesting or different .
If you put vids out then what do you expect and its not as good as Top Gun Maverick ....is it ?
I am not good at vids but occasionally put pics of work I have done . If someone doesnt like them fine but I like to know.
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1 min in and eyes were drooping 😌. Not as good as Top Gun Maverick.
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Keep up the fight Matty.
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You do need a proper fit/seal for the piston as thats how a diesel works. Looking at your picture of the piston it has rounded edges at the crown . This possibly suggests its not parrallel. These shoulders/ edges should be sharp as thats where the seal is important.
Re the contra-piston you could try the ball bearing and hammer trick.
No its not an early April fool joke.
Lay the CP on flat piece of iron. Find a ball bearing that will fit in the top . It must touch the bottom of the recess. Now tap it smartly. Test for fit in cylinder. Repeat until you get a good tight fit but dont over do it . If you hit it too hard the CP can shatter but nothing lost . Its a tip I was given many years ago and has saved many hours of making new CP's.
Some CL racing engines that used Cast iron pistons even used this method on the piston crown to finish races
Externally its looking good.👍
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Plus 1 for parcel tape with Solarfilm.
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1 hour ago, Martin Harris - Moderator said:
I’m not sure what’s given the impression that I’ve recommended adapting anything other than an unobtainable bearing. I thought I’d clarified that in my reply to JD8!
Sorry Martin missed that .
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The future of ic engines in our hobby.
in IC Engines
Posted · Edited by Engine Doctor
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 .