Engine Doctor

Hi John . I rewound it with new wire from a reel and used fresh wire for the second re-wind in-case the insulation had been damaged. . I did check each winding for short before connecting them up to one another.. I also made sure that all the winding were clockwise round the poles . I have re-wound other motors with good results and as Martin says they are so cheap now I only re-wound this for something to do one evening. Thanks for all you replies but its bin o'clock now.and will remain a mystery .

Hi All . Have tried switching two wires, no change .Have checked for open circuit and all ok. All winding wound as original motor in"y" as motor had loads of power. The original esc as stated was sold along with the plane some time ago , so still at a loss. Oh and throttle has been set to minimum. One thing that is odd is that this motor only has eight magnets. All the info i can find on the net suggests that nine stator windings should corresponde with 12 magnets ? Its making me think that the original ESC was matched to this set up although it worked perfectly with the replacement motor/fan unit from HK. The bin is looking a good destination

Hi can anyone tell me why this is happening ? some time ago I bought a F40 Tigershark EDF. On its first flight it burnt out the motor that was supplied ! Odd as it was set up exactly as described with all hardware supplied except radio and servos . Anyway the model has long bee sold on after many flights with replacement fan. I recently found the burnt out motor and thought I'd have a go at rewinding it for something to do. It has nine stator poles and eight magnets . I rewound it with 12 double turns in a "Y" pattern and all it will do is vibrate and jump but wont start ! thinking I'd got it wrong I stripped it out again and rewound it again taking extra care to get the windings correct . It still refuses to run and just sort of twitches . The speed controller it originally ran on was sold with the model but as I remember it was a standard 60 amp job . Any ideas or its last flight will be to the Bin !

As Your sorted now its not a problem but the engine cyl to starboard was , I think due to the exhaust on most two strokes pointing down and helped prevent hydraulic lock.when starting The Frog 3.49 was usually mounted pointing to the port as it had a left hand exhaust like many of the older engines .

Hi John . If you intend to use a 6v battery then dont use the JR as it is only rated for 4.8 volts .All the others seem to be OK for 6V. It also depends on the style of flying you intend . If you intend to prop hang then you will need fast powerful servos but general flying would be fine with something like a Hitec 645 or 625 analogue servo and dont use so much power. If you go the digital servo route make sure your flight pack has enough capacity to supply them and the rx .Many models have been lost through this especially with 2.4 radio ..

Ive used Hobby King quite a few times now and have been very pleased with the service until my last order from their Global WH in Singapore? I ordered 5 Frsky rx's including two of the 8 channel mk 2's that were on their website.I received an e-mail stating my order had been picked and carefully checked and re-checked and posted .All arrived very quickly. On opening the parcel all seemed OK except that one of the 8 channel rx's was the older mk 1 with the horrid case and had obviously been taken out of its pack , possibly a return. I tested it and it works fine . I sent HK a e-mail out-ling the problem and as the original post said returning was so difficult that it wasn't worth the trouble and that I would not be returning the item . They never acknowledge or apologised for sending what I thought was returned or at best old stock that was not even listed on their site. Obviously their checking procedure needs overhauling. Had the rx not worked I would have jumped through their hoops and returned it. On the plus side the cost of the 5 Rx's I bought from Hobby King totaled £52 and the best UK price was £72 plus a hefty postage charge which more than compensated for the different model .I will use them again as their prices are very good, but a bit dissappointed this time .

I did see a film /video somewhere of a chap making finishing a full sized prop. to balance it it was sanded until balanced perfectly . Then varnished. This caused some difference in the blades for some reason (possibly one blade absorbed more varnish than the other)Then the final balancing was by applying varnish . ie extra coat on lighter side until he was satisfied . similar to applying clearcoat

Hi Dylan have just read the thread. Have you tried fine line tape from auto motive stores? when you have applied it run along the required edge gently with a fingernail or the edge of a penny or similar. you will notice the area that is rubbed down will go a darker shade than the rest of the tape I use this a lot when finishing, usually with an airbrush. I do hand paint detail from from time to time and have found that removing the tape as soon as possible when the paint is still wet is the best way to go . It also stops the paint tearing or leaving a ridge.I also brush the paint along the tape with a bias away from it otherwise the paint is forced under the tape and WILL find any spots that re not perfectly stuck down. The method of seling down with the base coat is ok but it does leave a thick edge that can peel or tear.

Hi Fly boy3 .Did you get the splits in veneer sorted? Sorry I didn't reply earlier but I was very busy and then went on hols for a couple of weeks . As said most diy stores sell P/U glue either Gorilla or their own brand. This glue is also excellent for foam.

Hi Tom . It will help by turning the engine but you may still have to make a space for the exhaust in the fuselage where it meet the firewall . It should be simple during the building stage . Fit engine to firewall and make sure the thrust line is correct . Now fit your engine and tape up all the apertures with masking tape so as to stop saw dust from entering. Hold your exhaust in place and mark the area where the exhaust will foul the fus . With a dremel remove the fus skin and firewall until you have clearance for you silencer exhaust. Now shape a balsa block large enough to accommodate the exhaust and fit inside the fus over-laping the hole by about 1/2 inch all round. When happy with fit glue firmly to the firewall and fus skin . When dry simply grind out the balsa block with a dremel using a sanding drum or you could make a suitable sanding block with a peice of wood sanded to shape then gluing some sandpaper to it. Sand and remove the balsa block  until you have clearance for the silencer/exhaust.You should aim for about 3mm clearance to allow for vibration/movement. The balsa block once ground to shape can be hardened with cyano then sanded and finished. The De-Ag Spitfire flies very well and I have test flown quite a few now . The common problem with all of them is the aileron torque rod. They are prone to twisting and blow back during flight making roll response very poor.Simple to rectify during building by fitting a servo in each wing near the inboard end of the ailerons with a short push-rod.   Hope this helps Edited By Engine Doctor on 20/10/2013 12:30:47

Hi he holes in the hinge that fit into the wood should be filled with epoxy as should the slot that it fits into. Push home and wipe away excess epoxy with meths . If you dont trust it try doing a test piece . You will find that to pull the horn out you will have to pull out a big chunk of wood .This type of fixing is well strong .

Send a message to Clacksfield house and they will gee him up .

Hi Barry. I would be really sure before running an engine on 1% oil ! Perhaps thats why they are so rare Does the crankcase have any oil in it like a full size four stroke ? The 1% may be correct as only used for upper cyl lubricant

Hi . As said a felt clunk will stop the bubbles getting into the fuel line . Have you balanced your prop and spinner if using one? It is really necessary to balance the prop and spinner on Petrol engines as the engine can vibrate more than glow engines and any vibes from the prop or spinner will only make things worse . They do seem to be getting better and run quite smoothly compared to older petrol engines from a few years ago . As they are mainly made from commercially available parts some vibrate more than others. If you are using tank with a small neck that cant accept a felt clunk try using a sintered metal filter clunk. Dubro and Ripmax now supply them and they work as well as the felt type but are smaller and fit glow type tanks provided you have a petrol bung fitted. I would steer clear of putting any silicone in the petrol ; I know it works in glow engines but any build up of contaminants on a spark plug can cause difficult starting , erratic runningand sudden stops .

Hi Fly boy . Try using Gorilla glue or similar . It mends these cracks really well . Squirt it well into the crack and under the lifted veneer and then weight it down. when fully cured and foamed up (ie next day) just sand smooth and job done . Much quicker and cheaper than epoxy and glass and just as permanent .

Hi Martin. fitting a cowl is really quite simple . This is a link to a thread i posted on our clubs forum re fitting cowls . hope it helps. Re the Cof g . Some of the c of g positions on artf instructions can be way out. Have chat with a experienced club builder for advice . Failing that set the Bird Dog's cg at 1/4 of the chord from the leading edge at the wing root and you should be ok .Adjust rearward if you feel the model is a little slugish . Edited By Engine Doctor on 27/09/2013 09:06:24

Hi King E . As you have the west euro tech engine why not use westons own fuel Prosynth. Then when it goes bang ,which they do quite frequently at the rpm they spin, you will be covered by Westons warranty . ps I hope your club is not worried by noise as they will be in for a shock with the velocity!

Sorry Pete B and Skippy . Cant agree with your comment about getting used to it etc . Irresponsible idiots like this will only cause our hobby damage and bring about new laws and rules that probably cant be enforced anyway and will only harm genuine modellers . Who knows when the person flying these things at meetings are simply enthusiastic fliers or radical terrorists: is that a camera on board or an explosive device ? We cant un-invent these machines but we can control their use and that is what will probably happen . And you can bet on it that it will be a sledge hammer to crack a nut and possibly affect all our model flying.

Hi Andy . The pumped engines are fine once set up . The pump allows you to fit the tank virtually anywhere in the model, usually on the Cof G so that the trim of the model doesn't change as the fuel is used up. Persevere with it and you wont look back . One down side of pumped engines though is that the pump can get stuck up during storage ,even a couple of weeks. . Make sure that you can get a finger to the carb to choke to fuel through for the first start of the day . Dont forget that the tank needs a vent/ breather to allow air in .If overlooked this will cause the fuel mix to weaken and engine to stop.

Ripmax used top stock them but I think they are dicontinued. They sold a lot off at wings and wheels a couple of years ago and havent seen any about since . I had the Mustang , a great little flyer . Flew it to bits literally , actually the ground had a bit to do with it but good fun. Can the wing be repaired ? If not try Hobby stores they somtime do spares

De- bonding could also be unpredicted and dangerous . use proper fixings for engine mounts and high stressed areas . Altough a great flexible adhesive a dowside to sika flex is that once opened it will cure in the tube, an expensive waste . Curing in the tube can be delayed by taping up the tube thoroughly but not stopped .As already said go the blind nut/tee nut and cap head screw route .

It could be just an out of balance engine . I have seen it in the past ,two identical engines but one will vibrate really bad. I have two YS 140 and one is as smooth as can be and the other vibrates quite a lot. It hasn't shaken the exhaust off yet bit is still noticably more shaky than the other. I dont use any sealer ,tape or stuff on the exhaust. I just insert the header as far as it will go , screw back to align then tighten. Run engine up to temp and re-tighten while hot, as said previously ,using a good quality spanner .

I use Southern model craft 10% fully sythetic (No added Castor) on all my engines Inc Saito and 20% on my YS .I have found that the standard 20% oil ratio is more than enough and get SMC to mix my fuel with 17% oil . The little extra methanol gives a noticable increase in power over the standard fuel. No ill efects from lower oil content and YS 63 has been run for over 7 years with only one bearing change and stiil clean apart from slight staining on the silencer. The inards are still pristine with only slight discolouration on the piston crown.

Ditto Ultymate's post .

Hi John . Sounds like a punctured pump diaphragm .Needs replacing before flying .