Robin Colbourne

Jon, if you are getting the Dart to fire, it must be suffering fuel starvation immediately after this. What my father did on the DC Merlin we had in a Veron Cardinal that had this same problem, was to push a piece of hard balsa (1/16" or 3/32", I forget which) into the venturi. This left a small gap on either side and allowed continued running. Other things to check are that the backplate is sealed and that the crankshaft bearing is not leaking, as loss of compression in the crankcase would not help continued running. If you are using an exhaust prime to get it to fire, could the hole down the centre of the crankshaft be partially blocked with congealed castor oil? It is common with diesels to have to wind the compression screw in pretty smartly once the engine has fired, as it goes from a rich prime to normal mixture. You did not specify whether your prime was in the exhaust port, the carb venturi, or both. It is definitely worth doing both as this allows a little more time to get the compression screw wound in before the engine runs out of fuel. Fuel-wise, Model Technics D1000 has 5% more ether than their other two (D2000 & D3000) so is best for small engines. I suspect I'm 'teaching Grandma to suck eggs' with most of this. Hopefully you will find something to help though. Adrian, of Adrian's Model AeroEngines.com wrote the history of the Dart here. The Dart section starts just over halfway down the page. His Technical Topics are also well worth a read.

Andy, The Japanese pilot in 'Those Magnificent Men in their Flying Machines' was also called Yamamoto, so it is just possible that Bob Weston had him in mind when naming the model. Thanks to Terry Thomas's Lord Rawnsley, aided and abetted by Eric Sykes character, his chauffeur Courtney, Yamamoto's race hopes met an untimely end too.

If this Ebay advert is correct, the 743 silencer fits other engines, so the other engines' mufflers should fit yours. It could be worth asking around at your club to see if anyone has an early Irvine or an ASP/SC/Magnum silencer. Beware, as it was not unknown for the same OS silencer to be available with two different mounting hole spacings. This Irvine exhaust has the same 28mm hole centres as the OS743 silencer above.

I've bought from ee.bits several times in the past, all were posted items. I don't recall any problems.

Presumably this is the part, and prumably it will cost an arm and a leg once the UK importer orders you one?:

Its worth being aware that there are a lot of NiMH cells sold with vastly overstated capacities, even from packs in supermarkets. No doubt, someone here more knowledgable than me can advise the best way to charge and test new cells for their real capacity.

A rare Bowman's 'Trener' in the flesh on Ebay. Hopefully it will be relisted, if someone here wants it.

RedBaron, as you say, you explained to your cats the CAA's desire for us all to have RID transponders, and one of them looked at its bottom, as it clearly thought that what it heard must have come from there. That just about sums it all up! 😄

Great post Konrad. I really dislike seeing the top 1/3 of a servo sticking out in the breeze on an otherwise slippery airframe. What you wrote is certainly applicable to gliding between thermals, although when flying at min sink, the profile drag is less. A Schleicher K-8 or K-13 will out-thermal a slippery modern glider, but the latter will usually arrive at the next thermal faster and higher. Weight is fine if its actually doing something useful, however it is always worth asking oneself if a lighter material could do the same job.

The bit about LMA members who work at LMA events needing to be BMFA members is a bit odd. Presumably something to do with insurance cover for them or their actions. Otherwise if they are not flying why would having BMFA membership, or not, matter?

Ron, Does this club exist anywhere other than in your imagination at the moment? This thread seems to be the only mention of it on the internet. Whilst the ability to go and fly on any club's site when on holiday, or working away, would be a great idea, clubs closely guard their hard-won sites from those who come along, break all the rules, ruin it for everyone, then disappear never to be seen again.

The Model Pilot's Association (MPA) and later the Model Aviator's Association (MAA), offered several benefits that the BMFA did not. The primary one as far as I was concerned was the insurance it provided allowed me to offer paid one-to-one instruction. There were also the holidays at Brean Sands and Primrose Valley which were good fun. As I recall, both organisations were the brainchild of David Boddington, and the insurance was evolved form the MAP insurance that used to be advertised in Aeromodeller and RCM&E. The Model Aviators Association still exists, but focussed on the holidays only from what I can see.

If you have a look on the 4Max website, there are a lot of models listed with recommended set ups. If you find the model of theapproximate size and weight that looks closest to what you want to build and its expected performance (i.e. slow and draggy, or fast and slippery) then that is a good starting point. The KV number is the no load RPM of the motor per volt, so a 1000KV motor on a 3S (three Lipo cells in series) 11.1V battery with no load (i.e. with no propeller fitted) will in theory turn at 11,100rpm. The motor manufacturer will have a recommended maximum current draw which in turn will dictate the largest and coarsest prop you can use without exceeding the max current. Beyond this the motor and speed controller will get hot and inefficient. You can buy inline current & watt meters so you can see the current your motor propeller combination is drawing on the ground. There are a lot of Youtube videos that explain motor, esc & propeller selection, so it would be worth watching a few of them. The number on the motor, e,g, 2212/10T means the stator (the bit with the coil windings on, is 22mm diameter, 12mm long and each stator has 10 turns of wire on it. Watch out as I've read that in some cases the four digit number from some manufacturers refers the motor outer dimensions, not the stator. For a given motor the number of turns of wire on the stator decreases, so the RPM goes up. So an A2212/10T is 1400KV, whilst an A2212/6T is 2200KV. There are a few 2S setups with 30A ESCs in the recommended set ups list. Isabella by Marco Penk and First Step by Tony Van Munsteren are the first two. Have a look at the motor/prop recommendations to get a feel for what works.

I used Kevlar as I had some. It is a form of woven fibre along the lines of fibreglass and carbon fibre. You don't have to use Kevlar. I did because I had it. Glass cloth would be fine. For the amount you need it would be worth seeing if anyone who uses larger quantities can give or sell you an offcut. Bucks Composites supply to modellers. Something like this tape would work, or you could go for thier glass cloth, which is a bit lighter.

I hada Ripmax Dare-U which had the undercarriage bolted to a ply plate, which in turn was glued to the bottoms of the fuselage sides and longerons. Anything other than the most gentle landing would tear the undercarriage plate and the nearest balsa fibres out. Each time it was re-epoxied back on, the same would happen, just taking the next few rows of balsa fibres with it. The solution was to epoxy on a piece of glasscloth (I think mine was actually Kevlar, because I had some) that started an inch or more up the fuselage side, went round the ply plate and the same distance up the other fuselage side. This was on the outside of the fuselage, so the plate was pulled into the Kevlar, not away from it. Whilst the epoxy was still wet I gently wared it with a hair drier to make sure the epoxy fully wetted into the wood and the Kevlar, then covered it with a piece of polythene which was taped down as tight as it would go. This gave a smooth finish when it was removed, and blended in the edges ot the kevlar to the structure beyond it. Once it was rubbed down and covered in Solarfilm it was not that noticeable. The Kevlar extended fore and aft of the ply plate by about 3/4" as I recall. Another tip. If you use a scriber to poke through the mounting bolt holes whilst the epoy is wet, this pushes the fibres out of the way without breaking them. Coat the mounting bolts in a thin layer of Vaseline and screw them into the captive nuts. Then when it has all set, you already have them ready to use. To get a good bond, you need to have an oil-free surface, so if the model was engine powered, use Isopropyl Alcohol or meths, together with bicarbonate of soda or talcum powder to draw the oil out of the wood before you start the repair. One tip is to usethe point of a scriber