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Member postings for SIMON CRAGG

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

Thread: Floatplanes!
19/07/2020 07:51:40

A few of us have recently started seaplane / float plane flying, which I have to say is yet another fantastic branch of our brilliant hobby. So far, so good, but I am specifically interested in how others are waterproofing their models. It appears that there are several methods that would do the job.

Thread: Flying during pandemic.
03/07/2020 21:43:34

We have been operating a booking system via an on line diary.

Has worked 100%, and I have been at the patch at least twice a week from the start.

No joy this weekend due to the weather, back to the building board.

Thread: Prop advice please.....
29/06/2020 17:33:52

Have you tried punching the figures into e.calc?

You can try different makes / sizes of props

Different battery capacities and C ratings.

Worth giving it a go before you go much further!

Thread: SK3 Quandry
19/06/2020 06:30:05

Thanks Richard, not a method I was familiar with.

I have used the Wattmeter at every stage, but not felt the motor,

I have found it very interesting playing with various set ups on e.calc, and usually its not far off.

From what I have learned, its the amps that are important, so in this case I am trying to get as close to 42a as possible, but never over?.

Possibly sold the model to a club mate now, but after 40 years of ic, I find electric very rewarding when I get it right!.

Thread: Leisure or standard car battery for charging lipo's
18/06/2020 14:58:08
Posted by Christopher Morris 2 on 18/06/2020 14:12:22:

Some interesting theories on what to do.

  1. Change to ic/glow engine & fuel? Like the plane's sound, but my club has noise limitations at certain hours, but not with electric. Also,, the fuel smells & cost £25 a gallon. + the conversion of at least 4 planes. Pass
  2. Generator? got to agree with others about the noise. Surely, not from the ones flying noisy fueled
  3. Solar is a great idea's, but think i would need a few panels to get a quick charge on my 5000mah 4s ones.
  4. Batteries are another good idea along with solar as i would also have another use & could use it to charge the batteries for free at home. My trailer would be nice for adaptation for this use. Just depends if i can find cheap batteries & panels.

The other alternative? is i just buy some more lipo batteries for my planes. lol

Easy to get a really good high capacity battery from your local car breaker. Amazon is your friend for a good deal on a solar panel, or Facebook Marketplace.

Thread: Thank you again! Just Engines
18/06/2020 14:54:53

Didn't know they were still trading. Very off hand the last time I spoke to them. HobbyKing and Motion RC all day long these days.

Thread: The great i.c. / electric finger chopping debate
18/06/2020 14:52:34

I, and several others in the club use a physical tie back attached to the TX and the throttle stick. Seen to many horrors!.

Thread: SK3 Quandry
17/06/2020 18:53:16

Thanks Bob, understood. Does it matter if the Watts are higher?

Still cannot understand why e.calc is so different.

Anyway, as long as I dont damage to motor I'm happy!

17/06/2020 18:16:16

Ok thx.

I have tweaked the figures in e.calc. but they are still low compared to the readings I am getting.

If I stick with the 11x6 @ 42a 690w will that be ok, or do I need to get the watts below the spec. of 625w as well?.

I believe its amps that kills motors, not watts?

17/06/2020 16:58:23

Getting myself in a tangle!

For my latest project (Lb 5 low wing balsa model), I have got a Turnigy SK3 3542 - 800, Rated at 42a 625w.

According to e.calc:


12x6 = 582w / 41.95a

11x7= 515w / 36.8a

All ok so far.

So why are my figures so wildly out?

12 x 6 Dynam = 839w / 53a

11 x 7 APC = 757w / 48a

The only prop that is reasonably close is 11 x 6 APC @ 666W / 42A.

I am trying to stay within spec, especially the amps.Does it matter if I go over the Watts?

Can anybody shed any light on why my figures are so different to e.calc please?.

Thread: Leisure or standard car battery for charging lipo's
17/06/2020 01:11:23

I have been using the same car battery (from a breakers for £20), for the last five years. I keep it topped up at the field via a small solar panel. Works a treat.

Thread: 4 Max motor spec?
15/06/2020 12:01:18

In the process of purchasing a 5055 - 595 from 4 Max.

58amps, but no watts mentioned in the spec.

Anybody any idea please?

Thread: Dynam hurricane
14/06/2020 03:19:36

I have more or less given up with Dynam models, and moved on to Freewing. I am in the process of selling 90% of my IC fleet and going electric. My last few models have come from Motion RC (EU), who must have the best customer services bar none. Recently purchased (free post) the F18 Super Hornet, which was perfect apart from a couple of small dents in the tailplane. No problem, two days later, a replacement arrived from the EU. They mainly deal in the higher end models, but for customer support they are superb.

05/06/2020 15:39:43

The actual models look pretty good when they are finished. Usually, a couple of servos are duff, the hatch magnets are not lined up or won't hold properly, the wheels are tiny, the ESC may or may not work and is sometimes impossible to programme. I could go on! They are at the "cheap" end of the market, but it still makes me angry that they can get away with selling stuff like that!. Good luck and stay safe!.

04/06/2020 15:49:49

All the Dynam models I have had, come with some sort of problem or other. Some I have sent back,some I had replacement parts for etc. Once sorted mine have all flown really well. Its the quality control that lets them down. Can you send it back / have a good whinge?. I always used 5min epoxy to hold them together. Good luck

Thread: Most power i can get from a 6" prop
02/06/2020 13:01:31

Have you tried punching the figures into e.calc?

There are virtually limitless options, I have used it countless times.

Excellent bit of kit!.

Thread: Where in the final circuit to lower flaps?
31/05/2020 21:19:41

Another good tip is to activate "servo slow" on your TX.

Deploying 40 degrees of flap in one go, can cause all sorts of problems.

With servo slow, it gives you more time to sort out your throttle / elevator contol.

Have to say, I have seen a LOT of models come to grief by slowing up to much on finals, triggering a fatal tip stall.

Practice at height first..............and good luck!.

Thread: F18 Super Hornet
31/05/2020 20:43:14

Just had to share what a great day I have had flying my new Freewing F18 Super Hornet. Really looks the part, and not as bad as it looks to fly!. Now really sold on my conversion to electric. Brilliant day!

Thread: Web hosts
31/05/2020 07:14:52

Our club have been using a BMFA hosted website, and it works a treat.

Thread: Where are the Watts?
30/05/2020 06:48:09
Posted by OZ e flyer on 30/05/2020 01:42:42:

Simon I think there could be a simple solution to your problem. Work from your knowns and make sure it fits inside the maximums recommended.

for example;

You know the weight of your plane and the watts per pound formula to suit the style of flight you want to achieve.

you then know how many watts you’re looking for so that’s a known, let’s call it 400watts.

you know you know how many volts you’re going to have because of battery size (3s = 11.1 etc)

you know watts = volts times amps so 11.1volts times 36amps = 399.6watts

does that fall within the parameters stated on the motor data? If the answer is yes then you have a suitable motor. Select an ESC rated generously more than 36amps (50 maybe) then select and fit a desirable prop.
Using a meter, measure the amps being drawn during a static bench test.

if it looks like you are going to draw more than 36 amps at full throttle then fit a smaller prop and try again. A little trial and error until you have your desired pitch and size prop and I reckon you’re good to go.

I always add about 10% in to my calculations and I believe it’s always better to select slightly larger than you calculate you’ll need if it’s practical. It’s how I’ve always worked with my setups and I’ve never had an issue.

best of luck.

Many thanks, thats exactly what I have been doing so far.

Very clear explanation as well.

The stumbling block is "parameters stated on the motor data", which was where this thread started.

One great tool I use is "e.calc", brilliant programme where you can play around with all sorts of combinations, hours of fun.

I am getting there with converting ic to electric, and find it very rewarding.

Trouble is, after 50 yrs of ic flying it takes a lot of "getting your head round".

It looks like I have been a bit to obsessed with Watts, and not Amps!

Thanks to everybody!

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