Tony Patman

Update So, finally I got some time over the weekend. Sensibly I got the engine outside this time. I think I'm getting the hang of starting it now, but I still wouldn't call it easy sometimes. I noticed slight bubbling of oil from a point at the seal of the rocker cover. The nut locking the carb. barrel came loose and I had to tighten it again. The optimum main needle setting seems to be about 1 1/4 turns open. Now I'm trying to set the idle needed. I had the engine purring like a kitten at a steady idle, then it conked out and wouldn't start again; but the fuel tank was virtually empty and probably my glow igniter had expired!

I've been too busy to have a chance to fiddle again yet. Maybe on Saturday...

I haven't had much time over the past couple of weeks, so it's sitting on a shelf waiting.

Thanks Steve and all the contributors to this thread. Not only has it helped me enormously to understand what I'm doing, it being on this forum makes it a resource for all in the same boat. Hurrah for the Web!

Anyone who likes to do the maths could have a look at http://www.mh-aerotools.de/airfoils/propuls2.htm.

The transformer supplies 3A steady, 5A max. At 13.8v this is a maximum of about 70W so, indeed, not a lot. Time to invest in a battery...

OK, I've been on holiday and haven't had the chance to get down and smoky again yet. I have no intention of dismantling my engine. I bought a starter yesterday, but I think it might be faulty. Running it off my mains transformer (13.8v, a bit higher than the rated 12v), it needs a poke to get it rotating and it seems to have minimal torque. What, pray, is a Johnson rod?

Aha, now then, Flanker. The "bump" is interesting. Yes, I'm sure I've experienced that, but only once or twice. Maybe I'm not priming it enough. Raymond, yes, reading that review was indeed what made me buy the thing in the first place (magazine owners, take note, I'm sure you will). I don't dare start disassembling the engine, and I can't use a "harder" prop because of the design of the plane. I'm already on three blades because I can't increase the diameter any more.

Oo, I'm still catching up. I was starting on 1/4 throttle and then opening it up, as per SC's instructions. It's ok once it's going, it's just a b*gger to start.

Blimey. I go to Paris for work for three days and the thread explodes.

Danny, I believe I know what you mean about compression. Well, to my inexperienced fingers it feels rather weak, but it is definitely there. Are you thinking that there might be a cylinder head leak or something? I'm sure that the plug is in tightly and with the little copper washer. Now that you raise the issue, though, there is a slight bit of bubbling from where the muffler is attached! Very slight, though. Re. CO: no, I know it could be serious, that's why I'm not doing it down there again. No, the exhaust is not blocked in any way. Maybe I'll take a pic of the extraction system and post it on here, just to give everyone a laugh.

I'll have a look at the valves over the weekend. I have been scared to remove the rocker cover in case I disturb perfectly good settings without the skill to reset them! My flipping technique is to move the prop. anticlockwise until I can feel the compression, then flick it over the compression with enough impetus to spin to the next one. I have read about another supposedly more reliable technique which involves "bouncing" off the compression, but I haven't managed to work out how to do this. I will try without the exhaust pressure.

Some more "wisdom" gleaned: don't try to run your engine in your cellar unless you have an industrial-scale extraction system. Despite my efforts to create a local extraction hood around the muffler using flexible tubing, plastic flowerpots and an old inner tube I found in a skip, I still half-gassed myself and had to go to lie down until all the carbon monoxide had seeped out of my body. Next time I'll go outside and annoy the neighbours with the noise instead...

Hee hee, yes, fair question. I do mean the centreline, judged as the place where the main fuel line emerges. It's one of those Slec cuboid tanks.

Timbo - yes, it is new. No, I haven't checked the valve clearances because I don't have any feeler gauges and I would have hoped that they would have factory-set correctly. I think it is a bit sensitive to "wet", in both directions. I am sure that it gets flooded after a few flips: I have noticed that, if it starts, it generally does so quite soon after a "prime from dry". If it isn't going to start, I could stand there for half an hour flipping and it wouldn't go. Malcolm - I thought that too, about the tank, but it really is only about 3mm below the carb. Thanks for the tip about priming by blocking the muffler. No, I don't have an electric starter; but I was starting to consider getting one! This forum is proving so useful! Thanks, chaps.

You might find the following thread relevant: http://www.modelflying.co.uk/forum/forummessages.asp?URN=1&UTN=352&SP=&V=6#3200

Well, now it seems that two turns at most is quite rich enough. It's still a bugger to get going, though. Tony.

Interesting answers, guys, thanks. Sounds like my home-grown engine test stand won't last too long: I forgot to fuel-proof it before getting messy. Japlac, Tuffcote or Yacht Varnish: it sounds like there are many products which work. Last think I want is for my long weeks of labour to dissolve into goo...

OK, newbie ignorance. 1. What exactly does the fuel do to wood? 2. Is it true that a pot of Dulux will do just as well as specialised fuel proofer? Anyone else got questions?

I made a stand last week which turned out not looking unlike the Bromsgrove one, except that it is smaller and has a 45deg softwood brace between the base plate and the engine mounting vertical. Basically the stand is a square with plywood verticals, softwood base and top, and the brace at the business end: the choice of materials reflects more what I had lying around looking for a job than anything else. The engine mounting plate extends above the top side of the square, just like the Bromsgrove one, to allow mounting with the engine's carb. at a suitable height relative to the tank, which is held on the top of the square with a rubber band. Twang. Hint: put the band on BEFORE you glue the square closed. I made slotted joints 'cos I'm fastidious, but you could probably use metal angles or something too. I'll try to get a picture up on here over the weekend. I guess it took me about an afternoon to build, but I don't profess to be much of a carpenter so I expect a more experienced person could do it in an hour. Tony.

Will do. I'm going to have another crack this weekend.

I've been using the iron-on method and it works ok, but sometimes the paper and wood are scorched before a useful amount of black is transferred. The trick seems to be to apply extra pressure where the actual lines are on the paper; but anything other than a complete sandwich of the paper between the wood and the iron tends to allow the paper to slide around... I also used the plywood template method for parallel ribs, and it works very well. And on the eighth day, the Lord gave us...CNC cutting services. I haven't tried them yet, but transferring the patterns was such a faff that I would happily fork out a few quid next time. Does anyone know how much they charge?

Well, there's been the Wot 4 and the Wot's Wot and the Uno Wot. Has he done a Wot Ho yet? Or a Wot Eva? Wot Now? Wot Erunderthebridge? Wot next, that's wot I want to know?

Timbo, thanks for your helpful response. The fuel is new and the plug is an OS for FSs. I'm not sure about the idle needle because I haven't got as far as fiddling with that yet; but maybe I'll screw it all in and then out a couple of turns to reset it. I'll also try leaning the main needle down to 2 turns as you suggest. I thought 5 was too much, but you know what they say: RTFM. The glow clip is in fact one of the integral jobs with the cell in the handle, so there are no leads. I'll also try substituting some different tubing. Incidentally, the muffler pressure to the tank is already connected. Tony.

This is a bit of an epic, but I couldn't find an engine thread for novices yet, so I thought I'd start one and hopefully get some tips at the same time. Right, so I lovingly crafted a sturdy test stand from scrap wood (design available from me if anyone is interested), screwed the engine in place, balanced the propeller, mounted the tank less than 1/2" below the carb., dribbled some oil into the crankcase, tubed it all up, choked some (5% nitro) fuel into the engine and flipped it a few times to distribute it, set the throttle to 1/4, opened the main needle 5 turns as recommended in the instructions, attached the glow clip and then spent the best part of an hour flipping and fiddling until I was ready to throw the whole lot out of the cellar window into the garden. Then I figured out that the glow clip cell had discharged, so I charged it up and, after about 5 minutes more of flipping, the engine spluttered into smoky life. Great. I managed to get through a tankful of fuel; but the engine would stop as soon as I removed the glow clip. Might it be that the mixture was so rich that it immediately puts the fire out? The model is going to be a pusher, but the plan stipulates that the fuel tank should still be mounted facing forwards; something to do with orientation in flight, perhaps? this will need quite long tubes, so I have cut them accordingly. Could it be that they are just too long for the engine's suck-n-blow to cope with? I've noticed that, a few flips after choking, the fuel drifts back down the tube from the engine and it needs choking again to bring it back (or a swift puff into the pressure tube from the muffler, but this is probably not recommended because it introduces moisture, right?). Anyway, the engine remains very difficult to get going. The best I've managed for the past couple of days is some spluttering, then air bubbles appear in the fuel line and it stops. I don't think the bubbles are coming from the tank, but from the engine end. Also, the glow clip only seems to last for about 10 minutes before it needs charging up again. Is it supposed to be this difficult? Maybe I'd better start saving up for some leccy gear. Tony.