dlonrar

Thanks Ken, Yes, the engine did lean out when I held the plane nose up. I'll try opening it up 1-2 clicks on the TNV next time.

Flew plane today (cold with 6mph wind), after some of the following 'adjustments' in the hanger. 1. Noticed barrel of exhaust was leaking waste oil from joint, so lined joint with aluminium tape, re-fittened and tightened. 2. Flushed out carb with fuel. 3. Shortened fuel pipe between rear needle and carb. 4 Flushed out with fuel the top needle valve fitting with needle removed (done by pressurising the fuel tank when it was full of fuel). and At field: 1. Started engine , ran at tick-over for 1 min. 2 Set full throttle and leaned off to max revs. Riched up TNV and tested the nose up (engine leaned off but did not stop) 3 During the flight had none of the engine problems mentioned above in earlier postings, loops and rolls ok. Next check on the settings is a very cold (close to zero) windy (above 15mph day. Thanks all above for the suggestions and tips.

OK, thanks for all the suggestions. I have a lot to try, most of the suggestions I have tried before and I am thinking about scrapping the plane and engine. The problem only arises in cold weather. Currently the engine as had the top needle riched up from the summer settings. If I fly with the same settings the following day and its warmer everything is ok, maybe not perfect but there is no loss of power or surging. Suggestions so far, will have to revisit these: Grass seed, doubt this as I fly the plane off a tarmac strip. Tank, engine, fuel lead problems, air leaks – possibly not. As I changed the engine, fuel lines and tank last winter when I had the same problem. I was then using a SC 46 with a 11*6 prop and 5% nitro and it had the same problems in cold weather. I changed the tank (seagull standard – no brass fittings), fuel lines and ran in a new SC 46 with 11*6 prop using 5% nitro. Still the same problem, I changed to 10% nitro and the problem cleared. Or, had the weather got warmer? I think the latter, as this is the combination I flew through from Easter to the present day. I like the muffler idea, but how does this fit the engine getting hot and leaning off ? Hotter glow plug, possible, But does this go against the riching of the mixture ? Clunk position, possibly not as the problem can occur when flying level circuits with varying power. Is it a bottom needle problem? As the power loss is recovered by going below half throttle. As I understand it, the transition from bottom to top needle fuel flow is mid throttle ! Out of all the suggestions, I think I’ll stick with the top needle settings and post start up engine checks.

ok ken, Flew today. Conditions low wind, vis 800m , low cloud 400 feet, mist. Flew aircraft today, air temperature not as low as previous (problem) flight. No adjustments to needle settings. After take-off engine showed ‘surging’ problem, throttled engine back to half throttle, engine ok. After 4mins of circuit flying, rolls ok. Did loops after 6 mins and plane lost power as approached top of loop, decreased throttle to half and engine speed back to normal. Then went to full throttle ok. Landed plane ok. Allowed engine to cool and adjusted top needle as instructed, engine started ok. However, plane nearly died on take-off. Made it into the air safely. Loops this time had no loss of power, rolls ok. Did a few landings and take-offs ok. After third landing restrained plane and did standing engine rev test prior to take off, engine died. Hand tested engine temperature did not seem overly hot.

Thanks all for the entertaining and informative posts. I will try Ken's suggestion when the next spell of cold flying weather is around. Luckily I only live 5 mins away for the flying site.

I have an SC46 running 10% nitro fuel using an OS 8 plug, the engine runs ok with no problems during warm or hot weather (apart from the usual top needle adjustments). Flying in cold weather, the engine is ok on startup,idle, max revs and take off, but after a while during flight the engine revs surge (drop and pick up) without changing throttle position. Eventually the engine revs drop to idle or a dead stick occurs. Note, I have not changed the top or bottom needle settings since the plane last flew in warm weather, about 3 weeks ago.

Rick Tee, Yes, after many flights with the Tutor 2 I have found that 6 bands give the best result arranged in the way you have used. I did consider trying some 5" bands, so I wilI give them a go. Thanks for your post.

fly boy3, thanks for the informaton I will investigate further.

Just to update everybody. The replacement Tutor 40 mk2 is built and flying with new gear and engine. The previous engine, servos and rx etc although ok and useable are being further checked out. The plane has flown for longer and is proving to be what has been said by club members etc.... that the Tutor 40 mk2 is a well rated trainer capable of flying a B test'. Regarding the wing bands, I use 4 if light or no wind and 6 if the wind is above 10 to 15 mph. This might seem odd but that's learning by experience (the forces on the wing will be greater when flying in windy conditions than when flying in no wind). My thanks goes to the retailer and distributor for their prompt resolution to my emails and photographs of the wing etc

Once again thanks all, kc, yes the more I look at the plane and all the gear, there is a rebuild challenge and a wealth of expertise to be gained. See if I can build as well as in my early free flight days. Martin, yes I will stay with the retailer. Martyn, thanks for commenting on the wing. It was your wing rebuild that has given me the incentive to rebuild the tutor mk2. Edited By dlonrar on 23/05/2013 19:57:45

Thanks all, Martin, Yes, I will change the wing band arrangement and test the the wing for excessive free movement before flying. kc, I take your point about the wing bands. I have taken on board your points and added them to those of other club members, my instructor during the 'post flight debrief' and 'wing band topics' I have read. Before I posted this reply, I was contacted by the retailer and they said that the distributor had agreed to a replacement aircraft. This is great, as the Tutor 40 mk2 is a well rated trainer and I enjoyed the short time flying the first one. I will bear in mind all the points above during the build. Once again thank you all for your input.

Thanks all, Plumment, yes the instructor said the sudden pitch up is a charateristic a rubber band problem. However, the plane flew straight and true during the tests (responding to any direction changes). The rubberbands are the 6" white ones recommended by the plane manufacturer with 4 in situ (2 diagonal and 2 along the wing chord) Martyn k, I further checked the wing, and the 3rd rib (the one at the end of the wing spar is broken and part detached from the wing spare (glue still in place). The plane cannot be repaired as it nose dived from 150' onto a tarmac runway. The plane has had no previous hard landings and no previous damage to the wing. kc, yes I agree about the BMFA form, retailer etc. I think the information was sent to the distributor by the retailer because of the nature of the failure. I think a week is enough time to wait for answers and I am looking to take things further.The start was posting on the forum and I shall be informing BMFA.