John Minchell

Try Cloud Models https://www.cloudmodels.co.uk/contact they cut foam wing one-offs. John M

Anyone have a copy of the plan they want to sell, or will copy, or let me borrow to copy please? Any cost incurred will of course be covered. TIA John M

I just type the OP number into Word on the PC and duplicate it many times so I can print out on an A4 sheet of paper. Then cut with scissors and stick number side down onto a strip of sellotape then the excess sellotape around the outside sticks to wherever I want on the model. Number is protected with clear tape and removable if I sell the model or the number changes and 30 or 40 on a sheet of A4 plus tape costs next to nothing. John M

Normal aeroplane - you need the best quality and torque servo on elevator. A tug needs the highest torque servo on the tow release and same or next best on elevator. The rudder on a tug may also need a grunty servo if the tow line can pull against it but you still need the rudder to work against the side load of a glider on tow. Applies to the glider as well. ( strongest servo on aerotow release). Oh, and don't be tempted to use a retract servo - they are too slow to release after you have flicked the switch - don't ask how I know that!

James, Gliders Distribution do various ones for the glider end and may also have (but not on the website) tug ones. I got a 6 bolt flange fitting tug release from Stuart Mackay models - don't know if he is still trading. Also made my own as well - can take some pics if you need to copy it. John M

Very nice - interested to know why 4 servos in a 3 channel model?

Steve Webb models carry a line of really small DT indoor electronics - Rx, ESC, Servos, Spectrum clones etc. Also take a look at the Indoor RC FB page https://www.facebook.com/groups/619252605230388 as there are lots of tips + builds etc. which will build your knowledge base.

Thanks for all the replies chaps. The Dynaglow straight will get used in older "loose" two strokes and I have secured a gallon of Laser 5 at Steve Webb models for my Lasers.

Jon it is fuel specifically for Laser engines, or so I was told at the shop where I bought it. No castor oil and no nitro - Model Technics Dynaglow straight it is called.

I have some 8 or 10 year old Model Technics Laser fuel, probably 4 litres left in a 4.55litre container, but has been tightly sealed for that time. Will it still be ok to use? John M

I discussed this with Frank the other day on the phone as the same box (still unpacking after moving house) offered up the Merco 61 sparkie and also a 10cc Hornet from 1946 which I had refurbished. The thing is the Merco can go straight into a model and be run, but the Hornet or the OS K6 would need an rc carb grafting on and silencers making. I just fancied a 8 or 9ft vintage model with a sparkie for floating about at the end of a days flying and had a choice of powerplants for it. Looking at the Jasco Flamingo as a pretty model to build and will probably use the Merco, even though that is also NIB - but worth less than the OS or the Hornet.

Thanks Frank I saw that - and the estimate was only £60 to £80. Yes Jon a dilemma indeed.

Anyone ever used one of the replica OS K6 spark ignition engines in a model? They were made in the late 80's (OS only made 2000 of them). I have a NIB one and just wondering if it was worth keeping it un-run, or if it was ok to run it and use it? John M

Yes it's interesting in that it has a micro switch bolted just in front of the exhaust outlet and operated by a cam on the throttle arm so that at low (25% or less) throttle it retards the ignition to stop it being too advanced at tickover and stopping and throwing a prop. Says run it in on a 13x6 prop but can go up to a 16x6. Thanks for the weight guide Denis. John M

Here you go

I have a NIB Merco 61 spark ignition petrol motor and would like to build a vintage model for it. Just for floating around on calm evenings of course. Had thought of a KK Falcon but they are 10a penny. I have a few old timer gasser plans from the US, but really need to have an idea of the size / weight that the engine will cope with whilst leaving a bit extra for the odd windy day or for getting out of trouble. Any help appreciated. John M

Martin The outlet exits are shown on pic 2 & 3 at the rear of the yellow cowling - exactly the same as on a Tiger Moth or Chipmunk - a slight bulge at the rear edge away from the flat fuz side is the air outlet. It's only 3mm wide but 60mm deep top to bottom. Jon I can't cut away more of the flat side of the fuz because it would not be scale and cutting away inside the cowl on the side cheeks from the firewall back will not acheive any larger opening - just a sort of plenum chamber which is still restricted by the small side exit area. So I will cut extra holes in the lower firewall and tunnel them through to the wheel wells to get sufficient area/flow for extraction One last thought - do I need to provide a separate cold air feed to the carb instead of it using the warmed up cooling air from the front inlet?

Thanks Chris - really useful article on cooling so I've saved it. John M

Jon pics of motor in cowl. Model is inverted on stand. You can see that there is only a small inlet (44x20 = 880mm2) and I guessed I would need internal baffles to direct the air through the fins. But the exits on each side are very narrow (60x3 =180 x2off =360mm2) and add up to less than half the inlet area. Hence my questions. I can cut holes in the lower firewall and add some tubes to route the exit air into the wheel wells where it can exit around the periphery of the wheels which will add sufficient area, but is a lot of work which I don't want to do unless necessary.

What's the "rule of thumb" for cooling a glow ic engine (OS 90 FS) in a scale installeation. The air inlet is small in the front of the cowling (44mm x 20mm). Does the exit area need to be 2 or 3 times the intake area or even more? Any help appreciated. John M

Thanks for the replies gents Jon you have a PM. John M

Has anyone ever used or made a propshaft extension for either of these two engines? I have a scale installation and could do with setting the engine back inside the cowling so I don't need to chop a hole for the rocker cover to stick out of. But the face of the prop driver will then be 15mm or so short of sticking out of the cowling hole to put the prop onto. I can just use a longer tube nut to pick up on the standard crankshaft thread, with an enlarged hole in the prop hub and a 15mm spacer washer between prop and driver. Will the tube nut come loose too easily, as there would be no way the fit the second locknut to the shaft? Any help and guidance gratefully received. John M

I have used 4 max Ubecs in the past and they were fine, until one wasn't. A 6 cell LiPo supply and the 20 amp Ubec failed open circuit to let all 24volts through to the RX and servos. Unfortunately it was my 5m Thermik XXXL and it took out a 12 channel MPX Pro Rx as well as all 10 servos (around £600/£700 worth). Good job it was on the ground so no crash damage to the airframe. So now I will always use a separate RX supply battery in isolation from a motor drive battery and will never rely on a BEC in an ESC, or a separate UBEC ever again. However ymmv and everyone to their own decisions. John M

Here you go. John M OS FS 20 Manual_compressed.pdf

I just looked at my original plans for the Mini Super that I built in the early to mid 70's from an original KK kit and they have "copyright E Keil & Co Limited, Wickford Essex" on them together with a signature (on both sheets) of what looks like EJ Webster. So whether Boddo had anything to do with it originally and worked for KK or not, I will leave up to others to argue.