PatMc

Are you referring to the engine in the polyhedral winged vintage model ? There's a photo of an OS20FS in the post of 10.36 Monday.

Telemetry ?

That's because it goes with the Tiger Major as Sussex mentions. 🙄

The speed of series wound motors is roughly inversely proportional to the current, if they are run with little or no load they can reach dangerously high speeds. Typical damage would be the commutator disintegrating then the debris flying from it. These motors were (are ?) normally solidly connected to their load, never belt driven. Ref my 60 year old copy of Electrical Technology by Edward Hughes & my memory. If only I could as easily recall where I last left my specs. 🙄

OK, I missed the minimum prop size question but answered it anyway and addressed the follow on question by using an extreme example to point out the obvious impracticlity that could result

No they won't, the larger motor will run faster & take more current. See Mike Blandford's reply above. What point about minimum prop was made ? Where has a "motor's structural "burst" rpm" ever been specified ? As far as the motor's concerned there is no minimum size prop but you won't get far powering, for example, a Wot 4 with a 4" prop. All of our brushless motors can be safely run without a prop. We don't use series wound motors. Most of our brushless motors are "Delta" wound a few are "Star" (AKA "Y") wound. From the electrical POV there really isn't such a thing as specific voltage limitation but it wouldn't be practical to use a voltage that can only drive an impractical size prop within the current limit of the motor.

I've attached a couple of guides for beginners in pdf format that you may find helpful. There's more in each than you really need. If you have the "Quickstart" spring & finger mangler I'd advise not to fit them as they're more of a liability than help. Operating a First Diesel.pdf Quickstart_instructions.pdf

I forgot to mention in my previous pot to add a drop of washing up liquid to the water. This reduces the surface tension & allows the water to soak in deeper.

Sorry Matty, that's not correct. There is no absolute max power for a motor, however there is a max current it can take. Since power is the product of voltage & current the max power can only be stated with reference to the voltage that is being supplied. The max current that a motor can take is subject the length of time it's applied, how well it's cooled etc. The voltage will be limited to the practicality of the prop size at the motor's kv.

The motor is really only a power converter. The power it extracts from the battery is basically governed by the size of the magnets & the weight of copper in the windings. In practice you can estimate a motor's power output from any given battery by it's total weight. To a lesser extent there are some design features that effect the mechanical & electrical efficiency but these generally result in diminishing returns relative to cost.

One possible side effect of the Welsh 20mph restriction that hasn't been mentioned is that it may encourage more drivers to use "rat runs" through quiet residential areas. The speed limit will be the same as the "official" route, the distance will often be shorter, the only real disincentive might be traffic calming measures like speed bumps etc.

There are not many towns where a delivery vehicle can drive at 30mph the whole of the 30mph limited route, in fact they may not even be able to do 20mph for parts. In practice it's sometimes the case that a restriction on top permissible speed results in higher average speeds for the general traffic flow.

Prick the area with a thickish pin, squeeze a wet cloth on the dented area - the idea is to get the water into the pin holes. Now go over the area with a hot covering iron or household smoothing iron. The iron should be hot enough to turn the water to steam. The hot steam & pressure created will cause the crushed Elapor to expand from within.

Doesn't your second sentence example contradict the first example ? 🤔

But I'm sure you'll soon get over it However if you don't, don't worry.

Does he use each of the three words in rotation or just randomly choose which one he starts with? 😉

I never used a rubber finger stool or glove or a stick with diesels as it's often necessary to quickly adjust the compression screw & they would just get in the way. I always lightly sanded the sharp edges of the prop's TE (& LE as well sometimes) then generally mounted the engine sidewinder or sometimes inverted so that it avoided getting over primed causing over-compression or hydraulic lock problems leading to rapped fingers, bent con-rods & even broken crank pins.

Next thing you know they'll be referring to tailplanes as "horizontal stabilizers" & fins as "vertical stabilisers". 🙄

I don't expect ED's blatantly political post to remain after a mod has spotted it.

Similar to Don except I weigh them down on an old wardrobe mirror. The weights are old batteries & lead battery connector straps spread evenly along the length. I have also used books &/or magazines as weights with solarfilm backing plastic to protect them from the glue.

I think the non-anodised head means it's an old "standard" version. The Super Merlins' heads were anodised red, supplied with a spinner, tank, tommy bar & propeller also the hint that they were hand picked as having better than the standard power which they weren't & didn't 😉 The standard model was advertised as the budget model with no extras. I don't think the Merlins were ever under rated. They were very popular as a F/F sports engine, always known to be more powerful & cheaper than the Mills but not as easy to start or tune or as flexible with prop sizes. The Mills was the better engine for beginners or anyone who put reliability above a marginal difference in power in the type of model that usually had the engine running deliberately off tune anyway.

Both engines were bought second hand (along with several others) not long before the pics were taken in 2006, I went all electric about a couple of years later. I'm not sure if I got round to removing the "starter" bits from that pair but if I used them I would have done as I found them more hinderance than help. IIRC the tanks fitted to the AM 10s & 15s always leaked, early ones were metal later were plastic. I've got a couple of AM10s & one 15 only ever used them for C/L or RC models but always with separate tanks, in fact I can't remember ever using the supplied tanks on any engines except for Cox & Kiel Kraft 049's.

Later versions of the Merlin had plastic then metal tanks retained by a single central screw. Early Merlins had smaller plastic tanks retained by the same backplate screws.

With a universal 20mph limit speed bumps may prove to be unneccesary. If so perhaps they could be removed then recycled as pothole fillers. 🤩🤩🤩

I expect Lilly put it there. 😉