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Member postings for Engine Doctor

Here is a list of all the postings Engine Doctor has made in our forums. Click on a thread name to jump to the thread.

Thread: Has Your Club Made Any Decisions Regarding The Coronavirus?
19/03/2020 10:29:57

We have cancelled all indoor and outdoor organised meetings until further notice. The flying field is still open to members for normal flying as it's easy to distance from other clubmates. As already said when a full lockdown is brought in then the field will also be closed.

Just wondering how I'm going to cut the long grass when we can finally get back out ?indecision

Good luck to everyone and keep well.

E.D.

Thread: Motor stutters near full throttle
12/03/2020 11:04:27

I have had this problem on one of my planes. It sometimes wouldn't restart after closing the throttle but would just oscillate . Problem on that model was poor quality / connection on the bulit conectors on the motor leads. Another model with similar problem was a broken lead in motor.

Thread: David Boddington Tiger Cat
08/03/2020 12:23:34
Posted by Denis Watkins on 08/03/2020 11:46:39:

If you don't fancy an Old 20 Kevin

ASP do a great .21 that will fly 36" wing a treat

Just looked on Just engines and ASP 21's are now out of stock with little hope being re-stocked . You might be lucky and find one in stock somewhere.

Hopefully their new range of Taiwanese engines will grow as they only stocking a 15 and a 32 at the moment.

Thread: Saito 300 Twin
07/03/2020 14:17:45

As your Saito was designed for use with methanol fuel then changing it to run on petrol has caused the valves and seats to erode due to the hotter exhaust gas eroding the valves and seats . Classic cars and motorcycles suffer from a similar problem of valve seat regression due to the use of modern fuel/petrol not having any lead in it. The lead would act as a lubricant and stop the valves and the standard softer seats sticking or being damaged by the excessive heat . The cure is to have new hardened valve seats fitted that can withstand the temp of the new fuel without the lead . The bronze seating fitted in the Petrol Saito' is there for that reason . If the valve seats are not too damaged/regressed (any pictures ) then a new set of valves may fix the engine but the cure then will be to run it on methanol in future . You could still use the spark ignition with methanol for added reliability and get more power than petrol .

New cylinders for Saito' are expensive as head and cylinder is a one piece casting  so fixing your engine will probably cost £250 plus Unless you can find a cheap breaker with the parts you need .

OS engines have bronze valve seats as do other FS engine makers . Not sure though how they would stand up to use with Petrol as the composition of the seat material may not be up to use with petrol unless its purpose deigned for petrol.

Best of luck with re-build

Edited By Engine Doctor on 07/03/2020 14:20:05

Thread: Pin Holes
26/02/2020 09:23:45
Posted by Rob Fairweather 1 on 25/02/2020 21:18:07:

A +1 for the saliva/spit solution , been using that method since 1966.

Very interesting . have used it on dents in balsa but never tried it on pinholes . Will try that on next build .

25/02/2020 17:39:34

Try some water based filler like polyfiller or polyfiller light . Sands really easy once dried and adheres well There are also many lightweight fillers on sale at Diy stores . If area is prone to twisting try some Ronseal Woodfill. Its a two part filler that sets in about 10 minutes a little heavier than the light stuff but wont shrink or fall out , its easy to sand and comes in white or beige .

Thread: Hello Bedfont calling
24/02/2020 14:05:12

yes As per Matty B says . They are great little models but not for a beginner . If you smash it you wont get any bits . Ripmax sold all the old stock off at Wings and wheels about ten years ago. They sold them off with motor and a speed controller for about £30 . The motor is a cracker , a canned out runner with plenty of torque. As for servos any reasonable 9 gram servos will do the job . Good luck and happy landings

Thread: SC 70 fs
24/02/2020 13:37:06

They are I believe cast into the head casting and are not removable . You may be able to get some type of thread lock , even cyano into the join and fill the leak . Its worth a try . I have never bothered trying to stop the leak in the past but may try if one come my way in the future . You may be able to find the leak by blowing air into the inlet and exhaust ports having first re-fitted the valves . The SC etc are poorly built engines compared to OS etc but generally run well enough for our needs .OS use the same type of seat but I have never found any of them to leak . If you do try to seal the leak let us know how you get on .

I backed a Magnum 160 FS twin some years ago as one cylinder had no compression and kept going out. The supplier tried grinding the valve numerous times and had a perfect seal but it still blew past the valve seats once fitted on the engine . He finally gave up and fitted another head and guess what ? That had the same problem but not as bad !

Thread: Closed loop...
24/02/2020 11:51:34

Provide both lines are tight around the center then it should be ok . And its when rudder/ elevator is around the neutral position that flutter will cause a problem if lines are slack. When inputting control movements the pulling line will / should but enough tension to stop any flutter Unless you get the geometry absolutely accurate then the line pulling will always be tighter. Make sure that the width of the horns and the servo arm are the same diameter and that holes are the same distance from the center-line and it should work out

Thread: DB Hurricane paint and finish.
24/02/2020 11:41:33

Hi John you can get a soft sprayed edge by using some foam edge masking strip . Its primary use is for sticking inside car door jams to get a soft edge . I used it on a yellow aircraft spitfire to great effect. Downside is its expensive if you have by a whole box . A car repair shop may be able to help with a smaller quantity .

Thread: Whats easiest way to clean an engine without dismantling?
23/02/2020 15:42:20

A friend used to put his engines in the dish washer ! When finished he gave them a thorough run and all was well .

Health warning !!! Only try this if SWMBO is away or out for the day wink.

If they are gummed or siezed see post re "Jammed engines "

23/02/2020 15:41:14

Sorry double post

Edited By Engine Doctor on 23/02/2020 15:42:59

Thread: SC 70 fs
23/02/2020 15:32:38

Hello Richard. It is what it is i'm afraid and no cure other than replacing the head as already suggested. But ..........the new head could be exactly the same and allow gasses to escape past the bronze inserts . No amount of grinding the valves will improve the compression . Look for a smashed 70 with broken lugs or crank but one you can feel the compression on and swap the heads. Although good luck on that one as folk seem to not want to get rid of old four-strokes even if they are busted ?

Anyone buying a ASP, SC or a Magnum FS engine check to see if it has compression. Even if its new and un run check it .It it has little or no comp then its as useful as a chocolate tea pot , and will not idle reliably or deliver full power .

Anyone with an old clapped Enya 90 FS ? I'm looking for a head and a crank .

E.D.

Thread: Jammed OS engines
23/02/2020 11:08:07

Re gummed up engines. Beware ! I still have a damaged con rod (oval big end)from a OS Gemini twin on my key ring as a reminder of what damage castor can do when it sets like varnish inside an engine . I bought the engine in a clipped wing Cub many years ago. It was very clean and showed no signs of burnt on castor . Engine felt a little dry but not gummed or stiff as it had not been flown for a year or so ,according to the previous owner. Engine was thoroughly wetted with fresh fuel and started easily. After a short run it started making a knocking sound and was immediately stopped. On investigation both con rod big ends had been badly damaged ,fortunately the crank escaped and was reusable. The culprit was castor oil had set in the big end oil holes like varnish plugs. Had this happened today then the Gemini 120 MK1 would be scrap as con rods were only available second hand back then !

Since then I always strip clean and check oil ways are clear. Similarly I Never used castor based fuel on any glow engine two or four stroke.

And before any fuel gurus start on about the merits of castor ,yes it has its place in vintage engines and WW1 engines , and old vintage model engines that need a thicker oil.

Three - in - one oil was mentioned. What ever you do don't use it as a lay up oil. It's acidic ,will stain casings and sets up like varnish . A good quality air tool oil will keep your engines free and protected for those long lay ups or general after run use.

Thread: Stuck piston ring
19/02/2020 17:01:23

Glad you sorted it Ted. Its a very slow process to get a ring un-stuck and they unfortunately sometimes break just when you thought you were winning . Worth knowing that the OS ring is the same size .

E.D.

Thread: Building a Depron Vulcan (smallish)
09/02/2020 07:48:28

Polyester base coat WILL eat normal foam but was ok on my EPP model . Always do a test before painting any material in doubt .

Polyester base coat is a solvent based colour paint used on cars etc then coated with a clear 2k laquer .

Water based base coat is now available and will coat foam without damage but you will need spraying equipment and then give it a coat of Ronseal or similar to protect and seal it. The water based paint will be ok on any type of foam.

Good luck

Edited By Engine Doctor on 09/02/2020 08:13:29

Edited By Engine Doctor on 09/02/2020 08:15:15

08/02/2020 17:47:18

I have recently re painted an epp edf model . I thought I had some artists acrylic in the red I wanted but it had gone hard in the bottle . I had an aerosol of bright red polyester base coat left over from painting my sons Fireblade years ago. After testing on some epp scraps it looked good so painted model. It gave a fantastic red satin finish. On that basis you can get it in good proper metalic as its used on cars and bikes etc. I have clear coated it with some ronseal to give better protection . The polyester paints/basecoats can be bought from car poaint factors in aerosol if required . Not cheap but cover well and go a long way.

Thread: Web Cam?
08/02/2020 11:29:20
Posted by FlyinBrian on 08/02/2020 11:12:12:

The main problem will be to stop it getting nicked or vandalised.

Agreed our site has had problems with stuff being nicked , shot with airguns or just smashed up . A great tool if you can disguise its location from local yobs . What is the power source etc that you are going to use ?

Thread: Medway MFC indoor flying Sun 8th December . Gillingham Kent
08/02/2020 10:51:39

Medway MFC .Indoor flying this Sunday at Medway Park leisure Center Gillingham Kent .ME7 1HF

Starts 10am ends 3pm £7-50 to fly £1 to spectate ALL proceeds go to the Kent Surrey and Sussex Air Ambulance . BMFA cover required to fly

We will be having a free "Bring and Buy "table .just donate something to the air ambulance box if you sell an item .

A raffle

Vintage style round the pole combat flying , Rc 3D and scale /light weight Slots, free flight, helis and drone flying .

Weather is looking rubbish so hope to see some new faces.

MMFC

 

Edited By Engine Doctor on 08/02/2020 10:52:52

Thread: Futaba
06/02/2020 09:57:15
Posted by Trevor Crook on 05/02/2020 21:55:00:

My money is on throttle reversing too - I think Futaba's throttle direction is reversed relative to most other brands, so you have to change it for most esc's.

Be aware that Futabe exponential sttings are reversed from other makes.Futaba use negetive ( - )expo for soft center on sticks while JR and I believe Spectrum use (+) positive expo for softer center movements. Get it wrong and you could have an exciting flight

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