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**maderdog_1024** · 10-09-2009, 12:55 AM

i have a 4s squall with a 70mm EDF too.
i also need a new impellar as it exploded in mid air.

The squall 4s(3400kv) uses a lower KV rated motor than the 3s(3800kv)
[url=http://www.ripmax.com/item.asp?search=squall]Ripmax - Search for 'squall'[/url]

Ripmax have the parts for 70mm EDF units but the 3 blade props are shit.

**Hangar-7** · 10-09-2009, 01:21 AM

If you can connect an ammeter and find out how much current is drawn at full throttle then knowing amp you should be able to work out the power of the motor.

At a guess I would say if your model weighs 800g then minium size motor you would need will be 550watts to get a good performance.

This site may help you thou they have limited info:

[URL="http://sussex-model-centre.co.uk/shopexd.asp?id=19942"]Hacker A50 Brushless Motors[/URL]

Cheers:cheers2:

**Si Goodchild** · 10-09-2009, 10:56 AM

Hey, that 4s Squall HP looks cool! Loving the vectored thrust attachment!

**Si Goodchild** · 10-09-2009, 12:20 PM

The Hacker A50s are a bit too big and the other motors in the series don't seem suited (mix of KV, power and size). I'm after a high KV rating (say 3000+) working at 4s and delivering as much power as possible (say 600-800W) all in a 28mm dia case. It's interesting that the squall hp uses a lower KV rated motor in the 4s set-up than the 3s and a 3-bladed prop instead of a 5 bladed one to prevent the motor from bogging. The lesson appears to be that a balance between KV rating and prop design needs to be struck.

So if I stick with the 5-bladed prop and 4s setup in my F16 would I be better off with the 3200 or 3700kv Turnigy 2836 motor? Any other (cheap) motor suggestions?

Maderdog_1024: you say your Squall HP has a 70mm fan, yet the RIPMAX link says 64mm. You also don't rate the 3-bladed impeller which is standard for the model, so what is your setup?

Si

**Hangar-7** · 10-09-2009, 01:52 PM

Si Hi!

I agree Heckers are heavy weight but powerful motors. I think Sussex Model Centre have some heli motor as well and I find them to be helpful. Might be worth a phone call.

Combination of a motor and prop is more than often a matter of trial and error IME - if the combination is not right then you'll be burning AMP at a faster rate - i.e. short flying time. More number of blades means you can afford to run at a slower speed i.e. 3200kv and 3 blades will most likely need higher speed but then length of the impeller needs to be taken into account as well

BTW, I am using Turnigy 4000kv(£12) motor in my T450 without problem. I have a Scorpio as a stand by but now i'm thinking I might sell it (probably wouldn't).

Cheers.

**maderdog_1024** · 10-09-2009, 10:26 PM

found this online too;

found a good alternative,
EDF Unit> [url=http://foamyjets.co.uk/index.php?act=viewProd&productId=44]Foamyjets UK - Het 6904 Fan (Powered by CubeCart)[/url]
Motor> [url=http://www.e-flight.co.uk/shopexd.asp?id=414]HET EDF 2W-20 Brushless Motor[/url]
Mad Motor> [url=http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=9045&Product_Name=The_Beast_EDF_Outrunner_4130kv_for_70mm]HobbyKing Online R/C Hobby Store : The Beast EDF Outrunner 4130kv for 70mm $118.00[/url]
sad american testing it;
[youtube]InNkf174lak[/youtube]

looks good :-)

**maderdog_1024** · 10-09-2009, 10:27 PM

[youtube]qW6qkNs5E9o[/youtube]

**Si Goodchild** · 13-09-2009, 11:12 AM

Blimey those look like quite expensive EDF "solutions"

I replaced the fan unit on my F16 with a like-for-like unit (this one: [url=http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=170375684828&ssPageName=STRK:MEWNX:IT]NEW 70mm duct fan unit for most ducted fan jet RC EDF on eBay (end time 24-Sep-09 09:49:02 BST)[/url]) but found that the outer casing is subject to flexing and even the impeller doesn't look very well balanced (it has a visible wobble), so I'm pretty disappointed as the new fan unit has already taken some self-damage during bench testing. I'll flight test later today, but I'm expecting the same old story of bad vibration (resonance) at about 30-40% throttle before smoothing out again at the higher setting. Trouble is, every time I go through the bad patch at 30-40% I'm doing more damage to the impeller and outer casing so in the longer term I'm gonna have to swap out the the whole EDF unit. I don't want to spend any more than I have to as I have a good motor (29mm dia and a 4mm shaft) and a good 4s ESC. Any ideas? I thought this might be a possibility: [url=http://www.edfjets.co.uk/edf70-with-3300kv-motor-assembled-26-p.asp]EDF70 with 3300kv Motor Assembled[/url] even though it has a new motor, which I don't really need.

PS (motor shaft isn't bent - I checked it out)

**Hangar-7** · 13-09-2009, 11:49 AM

This looks like a good system at that price and 14.8 V should be OK for your model. However, I have no personal experience of this particular ducted fan system... a phone call to the supplier?

[url=http://www.edfjets.co.uk/edf70-with-3300kv-motor-assembled-26-p.asp]EDF70 with 3300kv Motor Assembled[/url]

**Si Goodchild** · 13-09-2009, 02:01 PM

Thanks, guys.

The flight testing today was not great. Performance was fantastic but the noise of vibration terrible. The first flight was great apart from the noise, however a minute or so in to the second flight saw the engine cough (really, it was just like a misfire!) then okay for another minute or so then the engine quit completely. Glided in for a safe downwind landing and then the motor was okay again, so I'm suspecting thermal cut-out. I've now lost confidence in the ESC and fan unit so I might as well replace the motor too. So I'm looking for a complete ESC/BEC, motor and fan setup. Bummer!

The cheap and cheerful 64mm unit I got from HK (Motor, Fan and ESC for £20 posted) for my Typhoon has been an outstanding success so I'm almost tempted to do the same thing again with their 70mm fan deal (£25ish for fan, motor and ESC) but I'm concerned that the motor is only a 2600kv so may provide less thrust than I'm used to. So I'm open to all foriegn and UK-based solutions if they are of a higher quality.

Si

**maderdog_1024** · 13-09-2009, 09:57 PM

keep me posted as im too looking for an alternative for the squall that isnt bank breaking !

**Si Goodchild** · 13-09-2009, 11:04 PM

Right, more investigation...

Turns out that the "overtemp" was more likely to have been the impeller jamming against the casing. I've gutted the jet now and simulated this by stalling the impeller and the motor simply refuses to run again until the throttle is set to zero and then brought back up again. The vibration didn't seem too bad when I held the fan unit, but then again my hand will provide more damping than the foam jet structure so I reckon that's where the majority of the noise was coming from.

So, with any luck the ESC is okay. The motor shaft is, however, a bit bent. It's barely detectable but definitely there so I need a new motor and fan unit which is properly balanced. I'm gonna give EDFJETS.CO.UK a call tomorrow and buy that fan/motor combo which claims to give over 1000g of thrust because a: they're in the UK so fast delivery (ie before the weekend!), b: I can speak to them direct first, c: they claim to test each fan unit before they send them out (crucial) and d: the price looks pretty good too!

I'll let you know how it goes.

PS - what's bank-breaking about the squall - looks reasonably cheap from the link you supplied (although too bloody fast according to that video!)

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What kv rating?

What kv rating?

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