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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: Dynam hurricane
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!

29/05/2020 20:50:44
Posted by Richard Clark 2 on 29/05/2020 20:01:23:
Posted by SIMON CRAGG on 29/05/2020 19:36:43:
Posted by Alan Gorham_ on 29/05/2020 13:35:22:

There is an easy way. Watts are not the limiting factor, Current is.

So just prop your motor to stay within the max current limit.

Sorry, but most of the comments make no sense to me, apart from the one above.

Cheers anyway!

100 watts per pound weight of plane including battery is adequate for most propeller.planes.

If they don't give you watts in the motor spec just multiply the max current in amps by the voltage (roughly 4 volts per cell) and you have the watts.

Edited By Richard Clark 2 on 29/05/2020 20:02:41

Thanks Richard thats exactly how I have been doing it. Has worked a treat!. Latest motor is rated at 42A and am running on a 4 cell lipo, so its 625w which is more than enough for the old skool low winger that weighs just 5 pounds.

29/05/2020 19:36:43
Posted by Alan Gorham_ on 29/05/2020 13:35:22:

There is an easy way. Watts are not the limiting factor, Current is.

So just prop your motor to stay within the max current limit.

Sorry, but most of the comments make no sense to me, apart from the one above.

Cheers anyway!

29/05/2020 13:30:22
Posted by Alan Gorham_ on 29/05/2020 13:23:00:

Be prepared for lots of answers, but my take is that the Watts taken will vary depending on the number of cells you use (due to the formula used to calculate watts).

For example, it is possible to prop your motor to draw under 45A on 3S and on 4S and on 5S batteries. The Watts figure will thus be different for each voltage of battery pack you used, so a Max Watts figure is meaningless.

I thought that as well, For example: stated 45A x 14.8v (4s Lipo) =666W.

Some motors have a maximum WATTS in the spec.

Must be an easy way!

29/05/2020 13:18:03

I have converted a few ic to electric, but have come up with a newbies problem. When trying to decide on a suitable motor, I usuall opt for the "Watts per pound" option. Some motors include the watts in the spec, but other do not. For example a motor may have a max of 45amps, and 3-5 cells, but no max watts. Am I missing something here?. Thanks. Simon.

Thread: ATS Kite?
23/05/2020 12:53:46

A club mate has just had a "Barn Find" ATS Kite given to him.

Does anybody know exactly where the cg should be?.

Flies ok at third of the chord, but would be good to know where ATS suggests.

Thread: VE Day Tribute
10/05/2020 12:12:55

dsc_0073 (2).jpgdsc_0070 (2).jpgdsc_0069 (2).jpgdsc_0067 (2).jpgWe had our own tribute in the back garden!dsc_0065 (2).jpg

Thread: Will going FPV help me?
04/05/2020 09:11:08

Oddly enough this is my lockdown project.

I aquired a Ripmax Nova trainer from a club mate, which was due to be scrapped.

I am in the process of modifying it to take a 5.8 FPV camera / 300 Mah Lipo and TX.

At my end, I will be using a set of Eachine goggles with flight record facility etc.

Should be fun (eventually).

Thread: More thinners
29/04/2020 02:09:47

I got 10 litres for £18 delivered next day via e.bay. On a special.

Thread: Spare model in need of a home?
28/04/2020 16:23:28

Try Facebook Marketplace.

I have just purchase four 60" airframes for £10 each.

Lots of redundant ic stuff on the market at present.

Thread: Which classifieds do you use?
10/04/2020 07:38:41
Posted by Peter Jenkins on 10/04/2020 00:02:22:

BMFA Classifieds simply because of the choice and there is less chance of being ripped off!

Oddly enough, the only site I have been scammed on was the BMFA!

Scammers are VERY convincing, and prey on "niche" hobbies.

If it sounds to good a probably is.

Thread: If you like engines.........
09/04/2020 19:37:35

One day I might get a Royal Enfield Bullet.............looks vintage, but with a modern motor.

Probably never will, but just love the look of the range!

Thread: Which classifieds do you use?
09/04/2020 19:34:24

I have bought / sold over 640 items on:


FaceBook Marketplace





Best bet is to try all of them.

All good on the day!

Thread: Grass Cutting
01/04/2020 10:26:26

No, site out of bounds for the foreseeable future. Farmer and all members advised.

Thread: Flat Car Battery from non-use of car
01/04/2020 10:25:23

We use a small £10 solar panel proped up inside the windscreen and connected to the battery. Keeps the battery topped up pefectly.

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