Slo mo Shun

[Bob Abell 2Participant @bobabell2]

Sounds OK to me, Phil

 

We`re on the Home Straight now!……..Ooooooooo!

 

Bob

[Phil Winks 1Participant @philwinks1]

Just one  word of caution Bob I’d be tempted to keep the fans smallish no more than about 50% bigger than the motor diameter they do shift a fair bit of air and they will load the motors a bit. Not as much as in an edf setup as the exhaust is bigger than the inlet the exact opposite to an edf unit.

[Len OchiltreeParticipant @lenochiltree67043]

Hi Ashley,

Two identicle postings?, well it was ” Ground Hog Day ” !!.

[ashley needhamParticipant @ashleyneedham69188]

yes sorry.

 

I agree with Phil. I think something as simple as two or four blades, a bit of twist on the blades and round ends. Too fast an airflow might actually detract from a good circulation in and out of the boat hull.

 

Maplins for instance does a good range of alloy heatsinks, one of which you could glue on the motor casings with heat conducting silicone gloop, they would conduct the massive heat generated by your 1/2 horse (or whatever) motors into the airstream to be dissapated as global warming air currents.  I think I saw this on an Australian chaps type 21 frigate in THE OTHER magazine a while back?? looked impressive to me.

 

Ashley

 

 

[Bob Abell 2Participant @bobabell2]

Thank you Phil and Ashley for your cautionary words of advice.

Perhaps a simple twist of ali might be suffice?………Or the aero prop idea?

 

I fancy the glued on heat sink idea, Ash……….Thanks for that

 

What do we think of the aggressive looking terbo vents then?

 

Brrrrrrrrrm!…..Brrrrrrrrrm!……….etc………………Bob

[Phil Winks 1Participant @philwinks1]

Very nice indeed Bob I’ve been thinking about these fans and ducting and I reckon a 55/60mm 5 blade fan and a half pipe cover for the fan and motor would do the job ok without loading the motors significantly heat sinks on the motor would help too. thinking on I reckon I prob have a couple on some old pc fans in my bits box I’ll have a look over the weekend and let you know.

 

Phil

[Dave MilbournParticipant @davemilbourn48782]

Why do we have such a problem with a water-cooling coil, chaps? It’s cheap; it won’t take any power from the motors, and it’s been proven to work. I for one would not like to put my hand in there to operate a switch with a pair of ersatz circular saw-blades ready to sever my fingers.

Whatever happened to KISS (no – not the ugly, painted rock-band from the 70s!)?

DM

[Bob Abell 2Participant @bobabell2]

Hello Dave

 

Just inventing the wheel!…………..Don`t like waterpipes……You can never be sure it`s working…….Our pond is full of duck muck and algae in summer

 

What`s….KISS?

 

Behind the door Bob

[Len OchiltreeParticipant @lenochiltree67043]

Keep It Simple Stupid!

[Len OchiltreeParticipant @lenochiltree67043]

Keep It Simple S,,,,,,!

[Phil Winks 1Participant @philwinks1]

Suprised you didn’t know what KISS is Bob still never mind having had a sort through the shed I’ve spotted a fatal flaw in the idea of using off the shelf fan blades they’re all the wrong hand mate assuming that viewed from the motor the rotation is clockwise. all you’ll get is air moving the wrong way might be best to resort to circulating H2O, Shame cause I quite like reinventing the wheel too. Air scoops on the front might be suficient as I’m betting the motors etc won’t heat up much except at high speed

[Bob Abell 2Participant @bobabell2]

Good job you spotted the fan handing, Phil

 

I`ll stick with a new home made pair, but a lot smaller next time.

 

Well?…………What is….”Kiss”……?

 

Bob

[Bob Abell 2Participant @bobabell2]

Just noticed that this thread is the only thread that has seen any action today!

 

Where is everybody these days?

 

Bob

[ashley needhamParticipant @ashleyneedham69188]

Bob, the turbo vents are dynamic….what are they made out of please?

 

A bit of smoke effect from the `zorsts would be effective..?

 

Ashley

Edited By ashley needham on 05/02/2010 19:59:37

[Bob Abell 2Participant @bobabell2]

Hello Ashley

 

The Turbo vents are from Plasticard and I was also thinking today, that it would be rather novel for smoke to blast through!

 

A little oil bath with an RC controlled something or other to send some smoke signals?

 

 

Bob

[ashley needhamParticipant @ashleyneedham69188]

Bob, would that not imply that the engines were on fire??

 

Last year while I was fiddling with Berengar`s Seaplane, there was some wool on the table and he wanted some smoke effect from the exhausts, so we cut some 3-ish inch lengths of grey wool and stuffed the ends into the exhaust pipes (paper straws), so that when the motors were going the wool streamed out the back…like exhaust smoke.

 

Ok, not so hi-tec, but he was well pleased as were sundry other small boys and girls on the pond, and that is what its all about.

 

Ashley

[Bob Abell 2Participant @bobabell2]

I think I`ve got enough on my plate at the moment!

 

Just been thinking about working windscreen wipers?

 

Know anything about…..TURNIGY battery chargers?……Looks rather complicated to me

 

The instructions are written in a hotchpotch of English/Chinese!

 

Werry hard tu weed……..Bob

[Bob Abell 2Participant @bobabell2]

Phil

 

You say the TURNIGY battery charger is a good one……..Have you got one then?

The instructions say that I set the charging rate………How would I know that?

 

The batteries I`m using are….12v …4600 mAh…Ni-MH…10 cells…and there`s four of them

 

Any help will be appreciated………..Thanks

 

Bob

[Phil Winks 1Participant @philwinks1]

The simplest answer to charge rate is on your bty’s Bob to fill them in 1hr charge at 4.6A that will be safe however most sub C cells will stand up to 2c (capacity) charging so a max of 9.2A for those particular bty’s however I think your particular charger will only go to 5Amps if your charging AA cells I’d be more cautious and stick to a 1c charge rate and in both cases  keep an eye on bty temp if they feel hot then use a lower charge rate if one cell only gets hot change it. Keeping a log is a good idea stating charge rate pre charge volts post charge volts and MAh consumed during charge. Periodic full discharge and recharge on that charger will give a good idea of the state of the bty as the MAh input during a charge will reduce over time (a long time with those NiMh’s) set discharge cut off volts to 1v per cell. this test cycle should be standardised (ie dischg rate/rechg rate) so the results can be compared with previous results for that bty. Hope this helps not confuses. Ring me if you want a fuller description.

 

Now KISS it means Keep It Simple St***

[Bob Abell 2Participant @bobabell2]

Thanks for all that Gobble-de-dook, Phil!……..It`ll make more sense when I make a start on them

 

We`ve just come back from Prestatyn, where we had thick fog………..couldn`t more than 50 yds!

 

Bob

[Phil Winks 1Participant @philwinks1]

Ok Bob no problem any questions give me a bell  always glad help if I can

[Bob Abell 2Participant @bobabell2]

“Keep it simple, silly”!………He said…………..So I have done!…….No scoops and water pipes for me, shipmates!

 

New simplified fan shapes

 

I `m confident that this idea will be OK……………….Bob

[Phil Winks 1Participant @philwinks1]

Certainly simpler Bob I trust you’ll check them for balance (at least a dry run out of the hull ) we don’t want the motors shaking loose do we  

[Dave MilbournParticipant @davemilbourn48782]

Bob

Please test the aluminium paddles on 12v first. If you go straight for 24 volts then can I have an hour’s warning and full body-armour? Somehow Manchester doesn’t feel like it’s far enough away…………

DM

[Bob Abell 2Participant @bobabell2]

Hello Dave and Phil!

 

You two are beginning worry me now!………All these alarm bells going off are making me nervous!

 

Seriously though, I`ll be very careful……..I`ve tried them on a 12v jelly for a fleeting second and it was quite fearsome!…….The fan gave a hefty blow!…….Might have to make them a bit smaller and safer

 

I`ll make a perimeter guard before I try again, just to be safe……and wear goggles and tin hat!

If it appears dangerous, I`ll scrap the fans and go the water pipe route

 

Bob

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