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Member postings for Gary Manuel

Here is a list of all the postings Gary Manuel has made in our forums. Click on a thread name to jump to the thread.

Thread: Digital incidence meter
14/02/2019 17:11:12
Posted by MaL on 14/02/2019 13:05:00:
Posted by Gary Manuel on 13/02/2019 22:11:56:

I got a friend with a 3D printer to print me a set of parts to make myself an incidence meter - details HERE.

The Android app I use is called "Clinometer + Bubble Level", which I think is one of the better spirit level type apps. I've even invested a couple of quid to add "relative" angle measurement and measurements of angles using the built in camera. The App should suit your needs perfectly.

The problem with 3D printers and making things with holes is that the printer will tend to make the holes too small due in part to over-extrusion. Compounding the problem you had with your particular stl files is the hole in the incidencemeter_pince.stl is set to be only 7.9mm wide x 8.5mm tall. All the other parts with square holes were set to be 8.0mm x 8.0mm. In order to build a bit of clearance into all these stl's I have edited them to all have 8.5mm x 8.5mm square holes - that should make them a better fit on 8mm square ali tube.

Modified STL's available here **LINK** for 30 days......get them while they are still there

I did need to use a needle file to reduce the square hole size a bit. It wasn't much of a job, which just took a couple of minutes. Better too tight than too slack!

Peter, I know what you mean about the phone edges making the seating and measurements difficult to repeat, but it really hasn't been a problem. The phone tends to sit nice and solid and the measurements can easily be to tenths of a degree.

13/02/2019 22:11:56

I got a friend with a 3D printer to print me a set of parts to make myself an incidence meter - details HERE.

The Android app I use is called "Clinometer + Bubble Level", which I think is one of the better spirit level type apps. I've even invested a couple of quid to add "relative" angle measurement and measurements of angles using the built in camera. The App should suit your needs perfectly.

Thread: Model Museum ?
07/02/2019 10:05:33

I saw the request for info about this model on DVMFC facebook page and some of the feedback the lady has received already.

I must say that I'm not a great fan of Facebook, but when used n this way it can be an incredible thing.

Thread: Keep Those Old Cordless Tools Going
01/02/2019 14:46:33

fly boy3

I've just tried mine with a 3cell 2200mAh 65c Graphene LiPo and surprisingly, it feels like it's got plenty of power.

I would say it's well worth having a go with your 3 cell LiPo if you keep the mounting arrangement fairly universal so that you can switch to 4 cell when / if one becomes available.

Thread: Batt, problem mobile drill
01/02/2019 11:06:18

You could always do something like THIS.

I'm very happy with the results.

Thread: Westonuk cracking value for money.
30/01/2019 14:51:34

On that basis, THESE moon rocks were free. It would have cost much more than $850k to travel there are collect in person wink.

But seriously, I have found WestonUK to be great value, including the models that bear their name.

Thread: The Seagull has landed
27/01/2019 12:36:14

Hi Bruce.

The only problem I have with the model is the warped wing. It's exactly where I left it after my last post. I'll get round to sorting it when mojo / health / weather improve. There were no issues with the side mounted Saito.

Thread: Confirmation of a picture
26/01/2019 19:36:47

A pine headboard and 2 pillows?

Thread: Biggles' Mess (the renamed cafe!)
22/01/2019 13:31:12

Great news. An anniversary fly-past has been confirmed.

**LINK**

Thread: Which Watt Meter
21/01/2019 11:26:27
Posted by PatMc on 21/01/2019 00:45:04:

Oops, my slip up. embarrassed

You're quite right Gary, I put it the wrong way round, as you say power = I²R

However this doesn't change my point - with any given current the heat generating power will remain the same independant of the applied voltage.

As you stated V = IR but note in this case V = the applied voltage minus the back emf.

If the applied voltage is increased the motor rpm will increase by the same ratio, this in turn will increase the back emf by the same ratio & at the any given current the voltage across the windings will be the same.

What you are not recognising Pat, is that "R" is not a fixed value. The "Resistance" value is actually made up of the copper losses (impedance) and iron losses (reactance) plus friction losses. Copper losses are proportional to current and behave exactly as you have described, but iron losses are proportional to rotational speed. This effectively increases the value of "R" in these over-simplified formulae.

For a given current (adjusted by prop selection) with a higher applied voltage, the effective value of "R" will be greater, which results in greater losses in the form of heat. This is why a maximum wattage is quoted for a motor and this value should not be exceeded.

20/01/2019 23:28:13

Posted by PatMc on 20/01/2019 22:44:35:

Posted by Gary Manuel on 20/01/2019 20:54:45:
 

Sorry to dwell on this, but maximum power is based on a motor's physical ability to dissipate power in the form of heat and is related to it's mass and cooling ability. It's maximum current rating is based on the conductor size within it's windings. I maintain that neither maximum should be exceeded.

Gary, only the wasted power is dissipated as heat, the greatest part is dissipated in driving the load [prop].

As I stated previously, heat generated in motor (i.e. wasted power) = current x (winding resistance)² watts

Note this figure is dependant on current regardless of overall power.

PS since the OP has achieved his objective I don't think there's any harm in expanding the subject.

Edited By PatMc on 20/01/2019 22:48:59

Pat - Your second line is incorrect.

It should be heat generated in motor (i.e. wasted power) = current² x (winding resistance) watts.

It is dependent on current squared, which is derived from W=IV, where V can be substituted for IR so that W = I²R. The power wasted is a function of both voltage and current.

 

Posted by john stones 1 on 20/01/2019 22:22:40:

I love lecky advice threads, they're very competitive. yes

I like to think that we are being informative rather than competitive.

Edited By Gary Manuel on 20/01/2019 23:37:56

20/01/2019 20:54:45
Posted by PatMc on 20/01/2019 18:06:38:
Posted by Gary Manuel on 20/01/2019 17:37:18:

When choosing an electric setup, CURRENT and WATTAGE are both important. Exceed the maximum of either and you are asking for trouble.

A motor with a maximum current of 45A that runs nicely at (say) 40A on a 3 cell setup may overheat at 40A on a 4 cell setup if the maximum power rating is exceeded.

PS I use a HK Watt meter and can confirm that it works well.

Edited By Gary Manuel on 20/01/2019 17:41:21

Sorry Gary, that's not correct.
Exceeding the stated power (wattage) has no ill effect on a motor so long as the current is within the motor's limits.

I to use a HK Wattmeter, which IMO excellent. This one.

Actually "Wattmeter" seems to be a common misnomer. AFAICS all "wattmeters" for our use are in fact multimeters, in that they measure a range of parameters of which measuring amps is the most important & watts probably the least important.

Sorry to dwell on this, but maximum power is based on a motor's physical ability to dissipate power in the form of heat and is related to it's mass and cooling ability. It's maximum current rating is based on the conductor size within it's windings. I maintain that neither maximum should be exceeded.

I have exactly the same Watt meter as Pat and can recommend it.

Edited By Gary Manuel on 20/01/2019 20:56:21

20/01/2019 17:37:18

When choosing an electric setup, CURRENT and WATTAGE are both important. Exceed the maximum of either and you are asking for trouble.

A motor with a maximum current of 45A that runs nicely at (say) 40A on a 3 cell setup may overheat at 40A on a 4 cell setup if the maximum power rating is exceeded.

PS I use a HK Watt meter and can confirm that it works well.

Edited By Gary Manuel on 20/01/2019 17:41:21

Thread: Best Heating Option For Your Hobby Shed
18/01/2019 16:32:24

Mine's the same type of remote as yours.

Took me a while to find out how to pair it.

Thread: Ooooh Errrr! Don't know that happened here
11/01/2019 15:47:56

Just a though Adrian.

Could the original damage have been caused by the meter probes you were using to test the individual cell voltages?

Thread: Futaba 14SG chat
10/01/2019 16:18:19

I'm not a Futaba user but the curve looks to be the wrong way to me - i.e. try -20 instead of +20.

Here's a tip for checking that you have gone the right way with the expo. Set it initially to some really high value that allows you to really notice the effect. e.g. -50 or more. If it's working the right way, reduce it to a more suitable figure with the same sign i.e. -20.

Thread: Best Heating Option For Your Hobby Shed
10/01/2019 11:26:58

Martin

THIS one is a proper baffled one. I can't guarantee that you will receive exactly the same type as mine but I can guarantee that mine is a good un'. It arrived about 1 week after ordering.

06/01/2019 13:29:57

I'm not sure where the 2kW minimum setting has come from.

The specs I've read for the 5kW heater show the HEAT OUTPUT as 4kW maximum down to 900W minimum.

If 900W is too much then you need a different type of heater. I can't agree with the concept of leaving the heater on but opening the door / window to let the heat escape.

 

Edited By Gary Manuel on 06/01/2019 13:32:00

04/01/2019 20:11:01
Posted by Marc Osbourne on 04/01/2019 18:13:54:

Hi guys, we have got one of the 5kw heaters coming for our own workshop, what is everyone using as a 12v power supply other than a 12v battery of course, any ideas for a 240v to 12v transformer etc that could be used instead?

I'm using one of THESE. It works perfectly.

My heater is under a bench with the inlet and exhaust going straight through the wall behind the bench. This made filling it with diesel pretty tricky. What I've done is to fit a 10 litre fuel tank to the side of the bench, making it much easier to see the fuel level and fill it as well as having a larger tank. The power supply is now fitted inside the case where the original 5 litre tank used to be.

Thread: Biggles' Mess (the renamed cafe!)
04/01/2019 17:05:26
Posted by ken anderson. on 04/01/2019 16:46:09:

this is worth 5 mins of your time to read and admire.

ken anderson...ne...1...admiration dept.

Saw him on the news earlier. I hope a fly-past is arranged while he is still living. It'll mean so much to him.

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