Dave Hess

If you want to do something more complicated, try a Genie board. These things were designed for young schoolkids to program for their projects. Their advantage is that the programming is done by very simple block diagrams. The software is a free download from the Genie website. You also need to buy the programming cable, which is about a tenner. These things are an excellent introduction to PLC programming. The genie board will run from your receiver battery. You can flash things in whatever sequence you want, and you can PWM one of the outputs to adjust the brightness. **LINK** **LINK** **LINK** **LINK** Edited By Dave Hess on 30/12/2018 19:00:37

Posted by Don Fry on 29/12/2018 20:41:41: Can't get fingerprints on on off switches. A myth for the unknowing. Are you sure? I can see a big fingerprint on my PC's on/off switch. It's outlined in chocolate. Even the gatwick investigators would have a small chance of finding it if they were looking for fingerprints. Edited By Dave Hess on 29/12/2018 21:09:49

The police ruled out the two crashed drones, not because of the weeds growing through them, nor the spiders nesting inside, but when they got them back to the station and cleaned them up, they were able to find some DNA and fingerprints on the on/off switch. They both matched samples on their database, which turned out to be policemen who crashed the drones during training more than 5 years ago.

Ready made solution **LINK** Theory. Note that the resistors are labelled differently to above: **LINK** This will work down to receiver battery voltage. In the second link, I'd use a 100K preset pot instead of R2 to be able to adjust the frequency and a 1K preset for R3 to adjust the brightness. Bear in mind the 200mA limit for all the LEDs on the output. A single 5mm ultrabright LED takes around 20 mA.   If you shop around you can find flashing LEDs that work directly from a battery, like these: https://www.modeltrainsoftware.com/products/slow-flash-led   I used a red one on my boat when I was living on it so that it looked like there was an alarm, but all it was was a 12v flashing LED with a switch on it. The boat was in a dodgy area with no security and it never got broken into, so it worked. Edited By Dave Hess on 29/12/2018 16:07:00 Edited By Dave Hess on 29/12/2018 16:13:11 Edited By Dave Hess on 29/12/2018 16:15:59

Try adjusting the mixture screw. I'm surprised that nobody else suggested that. It's normally on the opposite side of the needle valve inside the throttle arm. Screw it out 1/4 turn. If it gets better, screw it some more until it's OK. If it gets worse, screw it the other way. Edited By Dave Hess on 28/12/2018 21:28:49

It's a lot quicker to hold your 1/16 strips over the spout of a boiling kettle. The wood goes bendy in seconds. Gue with PVA and pin in place. You can unpin it as soon as the PVA is dry, which will be a couple of hours in a warm place or overnight in a shed.

I don't think there's anything you can do now that the fibreglass is fully cured, other than cut and repair it. It most likely got like that due to improper handling or storage in the days after it was moulded, before it was fully cured.

There's nothing to stop you building a balsa fuselage, but if I wanted a new fus, i'd make one out of foam-board, like the Flitetest planes. I would think about an hour from start to finish.

Posted by bert baker on 27/12/2018 19:45:46: Nowt wrong with knife’s... Apart from the apostrophe! Sorry, I couldn't help it. Please don't hate me.

Phoenix upgrade still works. The desktop launcher checks for new versions whenever you launch it. That's how mine got upgraded a couple of months ago. I'm on 5.5.1 now. The launcher is version 1.2.

Mine's the same. It doesn't affect the thrust-line because it's only the foam behind the engine mount that gets compressed. To fix mine, I just stuffed in a load of expanded polystyrene balls, then poured in some foam-safe cyano and activated it when it had soaked down far enough.

Like with tradesmen, you should only use professional services that are recommended by friends and family or other due dilligence. There are crooks everywhere.

Posted by Frank Skilbeck on 20/12/2018 12:02:13: Not very scientific, but I've just got back from flying my Super Flying Models Fokker D7, I set the telemetry to give a regular amp readout every 3 seconds. With the throttle fixed to give 24 amps in level flight, putting the model into a steep climb the amps increased to just over 26 amps as the model came to the stall, in a dive the amps dropped to around 22 amps. Note very scientific but you can see how the motor draws more/less amps as the load changes. That's quite correct an exactly what I explained. The motor slows down when under load, so less back emf is generated and the higher net voltage pushes more current through the motor. The motor has no switch, valve or other mechanism to adjust its own current, so it has no way of changing how much current it draws. All that happens is that little gates open in the ESC many times a second and eletrons get shoved through by the battery voltage from one battery terminal to the other. They get hindered by resistance in the wires and the back emf trying to push them back the other way, but it doesn't push as hard as the battery, except at the theoretical maximum speed of the motor, which is why it maxes out. Edited By Dave Hess on 20/12/2018 22:38:52

Posted by PatMc on 20/12/2018 22:08:13: Posted by Dave Hess on 20/12/2018 00:03:48: The amount of voltage generated depends on the motor's speed and its Kv, and it's in the opposte direction to the battery voltage. A motor with a Kv of 1000 will generate 1v per 1000 rpm, so at 6000 rpm, it's generating 6v. Rightly or wrongly, by convention the Kv figure quoted for model motors refers to the rpm/volt applied not volts generated/rpm. Thus an unloaded 1000Kv motor will turn at 10,000 rpm when 10v is applied. The back emf = applied volts - (current x resistance of the windings) Edited By PatMc on 20/12/2018 22:13:11 That's just saying the same thing the other way round. The problem is if you explain it your way round, you can't see why the current goes up when the motor slows down.

Posted by Daithi O Buitigh on 20/12/2018 00:49:29: "A motor doesn’t draw current. Instead, using layman's terms, the current is pushed through by the battery." Congratulations, you have just failed City and Guilds 224 (Electronic servicing) A load draws current - a source provides voltage. Consider a river: the current is the rate it flows at and the 'voltage' is the pressure from the source pushing it along. Oh by the way, all transmitters have throttle trim so you should be able to set 'zero' throttle to a slow idle if you want to A motor draws current as much as the air sucks the water out of your hose-pipe when you wash you car or fill your pond. It's pressure difference that moves the water and voltage diference that moves electrons (current). You can always argue that the low pressure is sucking rather than the high pressure pushing, but that's pretty weird unless you're a scientist, in which case you're probably weird. Nothing wrong with being weird though. We're all weird in our own way.

Posted by Frank Skilbeck on 19/12/2018 15:57:00: One thing I have noticed is that an electric motor at a constant throttle setting will draw more current when the model is climbing, this is because as the model slows down the prop is doing more work and as the electric motor is trying to maintain the rpm it will draw more current. It's most noticeable when doing a loop and will often trigger an over amp sensor alert at a constant throttle setting. Effectively the throttle position is trying to maintain a constant motor rpm, whereas on an IC model it's a constant throttle position which is regulating the air/fuel throw and hence power of the engine, so when a prop is loaded up the engine will slow down unless the throttle is opened to a greater degree than an electric motor. But having said that, apart from a different throttle response and ability to cut all power on an electric model on landing and use the prop windmilling as drag, on similar sized/weight models I don't notice any real flying differences. My electric models range from 100 to 1800 watts and IC from 30 2 stroke through 90 fourstoke to 32cc Petrol. The other big difference is the longer flight time on IC. What you noticed is correct, but the reason isn't. A motor doesn’t draw current. Instead, using layman's terms, the current is pushed through by the battery. At zero rpm, the full battery voltage is pushing the current through it, but as soon as it starts to turn, it starts to generate a back emf (voltage). The amount of voltage generated depends on the motor's speed and its Kv, and it's in the opposte direction to the battery voltage. A motor with a Kv of 1000 will generate 1v per 1000 rpm, so at 6000 rpm, it's generating 6v. If you have a 3S battery (12v) and the motor is at 6000 rpm, you therefore have 12v - 6v = 6v pushing the current through the motor and at 9000 rpm, you have 3v, which will give half as much current. You can see that the current is simply dependent on RPM. When your motor slows down, the current goes up because it has more net voltage. That's why you burn a motor or ESC when you fit a propeller that's too big. As you have seen, your propeller speeds up and slows down along with the planes's speed, so the current changes with it - not a lot, but could be the difference between a problem or not; however, if you do a static test (plane static, not propeller) to check the current, it will always be higher than when flying, so if nothing burns or trips during the test, you shouldn't get any problems in flight. This explanaton is a little simplified for the sake of easy understanding. What actually happens is more complicated, but this is it in a nut-shell. Also, your battery voltage goes down during a flight and the current goes down in proportion, so a motor or ESC will more likely burn at the beginning of a flight than the end, assuming it's been going long enough to heat up.   Coming back to OP's question, for the reason just stated, you get very high torque the moment you open the throttle with an electric motor because you have low speed and high voltage at that point, which gives a much bigger torque reaction than you get with an IC motor. That means that you need a lot of rudder to counter it when you first push the throttle for take off. I'm going to be doing some experiments in the next couple of weeks to determine whether side thrust can mitigate that. I have one relatively light plane with no side-thrust that more or less turns a right angle to the left when I open the throttle quickly for take off, so I have to open it slowly. Edited By Dave Hess on 20/12/2018 00:09:04 Edited By Dave Hess on 20/12/2018 00:12:24

I know some people use electric guitar strings, which obviously come in a range of sizes. A top E string can be .008 to .012 inches, a G-string will bedouble that and a B half-way between. You can buy them individually or in sets. If you buy a set,they go by the size of the top E string, then the rest increase in size in proportion, so they refer to the sets as 8s, 10s, 12s, etc. **LINK**

Electric motors make maximum torque at zero rpm, while as IC motors make it at high rpm, so you get a different torque reaction when you open the throttle. There's loads of other factors that affect the way a plane handles. How much side-thrust and down-thrust did each motor have? Were they different sized propellers? How did those factors change the prop-wash?

For important things like tailplane and fin, I'd use foam-safe cyano.

It's possible to fly a drone at any range now using the 4G network and a smartphone or laptop. No need for a transmitter.

I've bought a lot of stufffrom Banggood over the last 5 or 6 year's including my excellent Jumper T12 transmitter that I use in preference to my Taranis. I also bought a couple of brilliant little RTF planes with SAFE receivers. I've never had a problem yet, though the stuff can take a few weeks to arrive. I've heard on other forums that they're very good at sorting out any problems. They have loads of RC stuff, including some nice looking balsa kits.

You can call me old fashioned if you want, but don't 6 year old girls normally prefer dolls to rc cars? You know that you can get an RC Barbie these days?

That motor will probably work, but it's a bit on the heavy side. I'd say that you should aim for one around 50g. I use one of these in my Scout, and it has more than enough power. I use a 10x4.4 prop with a 3S battery: **LINK** **LINK**

Duplicate post Edited By Dave Hess on 09/12/2018 23:47:03