John Stainforth

Posted by PatMc on 22/06/2017 23:00:31: Posted by John Stainforth on 22/06/2017 22:14:01: I should have emphasized the word *approximate*. Obviously the torque characteristics of ic and electric motors are very different. Still power is power. Actually I think that most ic engines are rarely used at their peak RPM power due to noise considerations whereas it's relatively easy to arrange an electric setup to give the required power. Fair point. However, I think there are many exceptions to what you say, i.e., there are ic flyers who seem to scream around the sky at more or less full throttle all the time, and electric flyers who find it desirable to throttle back considerably to prevent batteries and ESC's overheating.

Posted by PatMc on 22/06/2017 23:00:31: Posted by John Stainforth on 22/06/2017 22:14:01: I should have emphasized the word *approximate*. Obviously the torque characteristics of ic and electric motors are very different. Still power is power. Actually I think that most ic engines are rarely used at their peak RPM power due to noise considerations whereas it's relatively easy to arrange an electric setup to give the required power. Fair point. However, I think there are many exceptions to what you say, i.e., there are ic flyers who seem to scream around the sky at more or less full throttle all the time, and electric flyers who find it desirable to throttle back considerably to prevent batteries and ESC's overheating.

Jon, Have you ever considered providing, as an optional extra, a drop-down carburetor intake tube (as on Saito engines) to bring the spray bar assembly closer to the centreline of the engine - to help with the tank placement in many aircraft? John

Most places further south are way warmer than the UK and more humid. It's no problem flying models in 40C+. There are several advantages. e.g. Exhaust grease cleans off the airframes far more easily than in cool climates, and you don't have to use the cylinder heads of your ic engines as handwarmers!

I should have emphasized the word *approximate*. Obviously the torque characteristics of ic and electric motors are very different. Still power is power.

I find the following approximate, simple conversions useful for model aircraft: 1 hp ~ 10 cc of i.c. engine size 1 hp ~ 750 W Electric motors are about 75% efficient, so you need a power draw from the batteries of about I kW for I hp. To summarise: 1 hp ~ 10 cc ~ 1kW of battery power

My advice, based on months of trials with many different packages, is to thoroughly test the contenders to make sure they really have the functionality you need. All the cheaper programs I tried fell short in some respect - such as inability to import 3D xyz coordinates, or commands that are inadequate (e.g a Rotate command that only works in one degree increments, which is not sufficient for aircraft design). I finally plumbed for Rhino - fairly expensive, but the license is for life, including all upgrades. If I had been prepared to spend even more money (e.g. several thousand pounds) I would have gone for one of the top of the range products such as Solid Edge or Solid Works. As others have said, it takes a long time to become really proficient with any of the better tools. I was told it would take me about a year, and it took me about a year! CAD is not difficult, just complicated: there are a thousand and one ways to do almost everything and finding what is best in a given context takes a lot of practice and trial and error. But I think it is worth it!

Amazing!

49 C in Phoenix AZ yesterday!

I look for several things: 1) If a scale model, how true to scale is it really? 2) Structure: the less clunky and more like an ARTF the better. 3) Does the structure look strong in the essential places, such as between the engine box, the wing spars (or tubes) and the landing gear? 4) If a scale model, be very wary of designs that move the spars or formers unnecessarily from their positions in the full-size aircraft. Remember that the designers of full-size aircraft are world class designers who know exactly what they are doing regarding stresses and the most efficient structures. 4) Are there plenty of interlocking tabs to make the structure as self-jigging as possible?

Threading servo wires and extension leads through wings is not difficult as long as the lightening holes in the ribs are somewhat larger than the connectors. All you have to do is drop a heavy nut on a cotton thread through the holes from either direction. It's just a matter of holding the wing vertical and jiggling a bit. The thread then has to be tied around the lead connector in such a way that the connector is not sticking out sideways, and then gently pulling the connector and lead through the ribs. I find this usually goes surprisingly easily.

For jigs, tailor-made balsa braces and templates glued straight on to a glass work top with CA - a la Dave Platt - are quick to rig up, accurate, and easy to remove. Much better than commercially available jigs IMHO.

Looking at my workbench, by far the most useful and most used items are: Glass table top workbench Swann Morton knives Cutting mat Straight edges for cutting Stacks of masking tape Many clamps of various sizes, elastic bands Razor saw and cutting frame Permagrit blocks (ca 6" and 12" - v v worthwhile Handdrill Dremel-type tool and *safety googles* (never use without) Decent set of Allen keys - long screwdriver type (i.e., with handles) with ball ends are by far the most useful for modeling Decent set of Philips screwdrivers (German makes seem to be the best) Other screwdrivers, needle-nosed plyers CA from Poundstore - 4 x 7g bottles for one pound! Aliphatic resin Slow setting epoxy resin Set squares

I think two elevator servos on larger models is a worthwhile redundancy. Also, this allows one to use two lighter and less powerful servos.

I have a Jet AFS dust extractor/air filter that does the job pretty wel l- it collects almost all sanding dust. To clean the filter I just bash it against an outside wall. It was quite expensive, when I bought it a few years ago.

Looks good! I notice you are also using an Aerogrip model restrainer, which I think is a really useful, clever device.

Really nice!

Maurice, I am also baffled by your problems with the covers of RCM&E. I have six years of them, which have been read and re-read, had sections torn out of them, and have been used as weights for building models. Some of the covers are very battered, and have collected glue splotches etc, but they are still attached to the magazines just about as well as the day I bought them!

I have just checked the BMFA rules, and rule (k) of Radio Control Flying Safety is very clear: "DO NOT OVERFLY houses, domestic gardens, car parks, traffic, railways, organised games or spectators. You may not be able to control people walking by at a reasonable distance from the take off/landing area but you should take care not to overfly them at low level".

As often seems to be the case, the AMA is much clearer on this than the BMFA. AMA's Rule 1 for flying RC models is: "1. All pilots shall avoid flying directly over unprotected people, vessels, vehicles or structures and shall avoid endangerment of life and property of others." AMA Rule 3 (re "flight lines" would also rule out such flying. AMA Rule 6 would also preclude this activity: "...no powered model may be flown outdoors closer than 25 feet to any individual, except for the pilot and the pilot's helper(s) located at the flightline."

"Nobody needs you when you're upside down... ...Everybody loves you when you're six foot in the ground"

Pure inverted snobbery!

But I prefer to remain in the air and not break it!

I visited this new model shop in Letchworth for the first time a couple of days ago and was very favourably impressed. The service was excellent and I was given a really good deal (about one third normal price) on a Blade drone plus camera. If you live in the area and have not yet visited this shop, I highly recommend you check it out.

I find the BMFA rule book a bit peculiar and rather old fashioned and prefer the AMA rules and guidelines in the US.