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Member postings for G-JIMG

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

Thread: Confirmation - The World Really Has Gone Mad......
19/06/2019 16:39:06

Unfortunately, because of incidents such as this, the cost of making the world idiot proof will, once again, be borne by the tax payer. Germany has already started introducing 'Repeater Lights' at crossings and traffic lights that shine the relevant coloured light on the kerb, in an attempt to attract the attention of the phone zombies. The measure is expected to be rolled out across the entire EU.

For the case under discussion, the report I read stated the Cyclist had passed through a Green light (a rare event on its own) before the collision, so presumably the pedestrian was that intent on her phone she was dawdling along when she should have been concentrating on the task in hand.

Thread: Wiring a Twin
18/10/2018 18:32:41

Thanks, I'd already figured out I need to disconnect both Red wires at the ESCs but it's nice to have it confirmed.

I already have 4S 3700mAh batteries, hence the statement that I need two of them. The model uses scale 10.5" 4-bladed props and the Battery/ESC/Motor combination has already been tested and proven to provide the required thrust.

I understand the rationale behind parallel wiring of the batteries and the benefits it can bring, but there is also battery life to consider, these things are not cheap! Although a slight mismatch is unlikely to destroy the battery(s) I understand that it could severely shorten their life.

Thread: ESC to Battery Wire Length
12/10/2018 22:36:45

Very good point BEB.

George has confirmed that his ESCs will work perfectly well with 20" ESC to Battery wire lengths. Apparently the improved performance is down to the capacitors installed within the ESC and the fact that the power Triacs are now more resistant to spikes. However, as you rightly point out, his statement only applies to his product.

Jim.G

Thread: Wiring a Twin
12/10/2018 22:28:38

George (4Max) can obviously only speak for his ESCs, which he guarantees will operate correctly with long ESC to Battery wire lengths (20"+). Apparently it's not just the capacitors they now use, it's also that the Power Triacs are now more resistant to spikes.

Regarding connecting the batteries in parallel; it's not recommended because if the voltage is different (more that 0.03V per pack) the current transfer from the high voltage pack can be huge and end up damaging both batteries.

Thread: ESC to Battery Wire Length
12/10/2018 12:37:11

Chris, I always intended taking George's advice, as you say, they're his products and he stands behind them.

I raised this topic because I'm new to the electric side of our hobby and was aware of conflicting views. Even in the 5 responses so far there's been advice to lengthen the motor wires and advice to lengthen the battery wires.

I've asked George what has changed within the "modern" ESCs to overcome the problem, I'll post his reply when I get it.

12/10/2018 12:02:13

Not according to George. The King Air will use two 800kv motors with approximately 18" of wire between each fuselage mounted battery and the nacelle mounted 45A ESC. According to him there will not be a problem with the wire length.

12/10/2018 11:29:00

Whilst designing my first electric model, a King Air 350 Twin, I came across the issue of wire length between the ESC and the Battery.
Tribal knowledge states that it must be kept as short as possible, otherwise the ESC will eventually fail. To mitigate against failure, capacitors should be inserted, "every few inches". However, I have been unable to find a definition of what constitutes a "long" wire or any details regarding the type, rating or distance of the capacitors.

To find answers I went to the expert and contacted George at 4Max. His response was, "The long wires on ESCs used to be a problem, but most modern manufacturers have designed around this and now long wires are no longer a problem."

So, who is right? Is there really still an issue with wire length or is the modelling community using out of date knowledge to solve a problem that no longer exists?

Personally I'd go with George's view; he's been right about everything else I've ever asked him and I see no reason for him to be wrong now.

What's the tribal view?

Thread: Wiring a Twin
11/10/2018 22:31:15

Trevor, The model is based on the King Air 350 Turboprop aircraft. Consequently, there is a large air intake directly below the prop hub and an even larger exit 'hole' in the underside of the nacelle. That's why I'd really like to mount the ESC directly beneath the motor, smack in the middle of the airflow.

The only concern I had was the length of wire to the fuselage mounted battery, but, according to George, that's no longer an issue.

Jim.

11/10/2018 22:16:02

Simon, I had the same understanding as you but couldn't find a definition of "long". I asked George at 4Max and his response was, " The long wires on ESCs used to be a problem, but most modern manufacturers have designed around this and now long wires are no longer a problem". I assume they've addressed the issue within the ESC itself.


Chris, Which 4Max UBEC did you purchase for your twin? He only has 4 for sale and the 20A version seems a bit of an overkill. I'm considering the 6A version.
I am taking photographs of the build and may well start a build log at some point, I just didn't want to be yet another guy that starts a log that peters out after a few months.

Jim.

11/10/2018 20:52:16

Thanks for the help guys.

I contacted George and he was very, very helpful. He determined that:

I do need two batteries because it will draw too much current with only one.
I shouldn't connect them in parallel because if there's a miss-match it could result in a high current condition.
Long wires between the battery and ESC is no longer an issue with modern ESCs.

Based on that, and using standard 'Y' harnesses as far as possible, the wiring will be as per the schematic:
ka wiring.jpg

As per Chris's comment, I will have to ensure the Right battery is always connected first to ensure the Rx is powered.

Jim.

09/10/2018 17:44:08

Until now I've always flown IC aircraft but my latest build will be a twin using:

2 x PO-3547-800 Motors
2 x PP-TESC45AV ESCs
2 x 4S 14.8V 3700mAh Batteries
1 x tbd UBEC

Question is, what's the best way to connect them? As two separate configurations with the UBEC connected to one of them (a), or with everything connected in parallel (b)?
wiring.jpg
Also, there is plenty of cooling in the nacelles so presumably it's a good place to put the ESC's, but the batteries will be in the fuselage requiring about 18" of wire to reach the ESC. I suspect that may be a problem, but I also suspect that two ESCs in an uncooled fuselage may also be an issue. Thoughts?

Jim.

Thread: Flap Servo Set Up
18/06/2018 15:37:19

Many thanks.

Jim G

18/06/2018 14:43:47

Just had a thought ...........................

I've never used Flaps before, is it usual to mix in Elevator? If so, how much as a starting point?

Jim G

18/06/2018 14:38:04

Thanks guys, all useful stuff.

I'll set it up as BEB suggests and take it from there.

Jim G

18/06/2018 12:18:01

Although I've built, and flown, many models in the past, the current build is the first with Flaps.

I'm using torque tubes connected to a single Servo arm, so movement of the arm moves both Flaps in unison.

What's the best way to set the Servo?

1. Set the Servo against the stops in the Flaps Up position and have all the drive available for deployment.

2. Set the Servo so it's nearly against the stops in the Flaps Up position so there's 'room for adjustment'.

Or, doesn't it matter?

Jim G

Thread: Rotary Couplers
18/06/2018 11:49:54

Thanks for all the suggestions, especially the homemade solutions. That's normally the way I would go, but in this case the wing is just too thin to accept anything much wider than the servo spline.

I'm using S3150 (10mm) Servos and there's not much room for much else. So unfortunately, on this occasion, I've had to open the wallet and buy a couple of rotary drivers.

rotary driver.jpg

Thanks again,

Jim G

15/06/2018 19:30:43

Hi Percy,

It's because I'm trying to make it as scale as possible, even to the point of adding panel lines, rivet heads, etc.

15/06/2018 15:29:51

Hi Plummet,

That makes perfect sense, but ............................ I'd considered a number of ways to make a coupler, including soldering a wheel collet onto a washer and then drilling a couple of holes in the washer so I could fasten it to a Servo Ring. However, the model's wing is very narrow and there wasn't enough room for anything involving Servo Rings or Arms to rotate.

The beauty of this product is that it comes with 5 adaptors, each with a different spline count, so it works with a number of Servo types.

Jim G

15/06/2018 12:58:42

Hi AVC,

Here's the link **LINK**

15/06/2018 12:39:42

Thanks for the help guys.

Dave, that's exactly what I was looking for, but for Futaba S3150 servos. However, your link led me to rewording the Google search, which in turn led me to a robotics company in Somerset that had exactly what I needed, and at a very reasonable price. Result!

Thanks again,

Jim G

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