Another billings slo-mo-shun

[Phil Winks 1Participant @philwinks1]

Well folks 7 coats of varnish and the shine’s begining to develop I reckon

 

So nearly there init

 

Phil

[Bob Abell 2Participant @bobabell2]

Nice shine there, Phil……I can see your face and camera!

 

Bob

[Phil Winks 1Participant @philwinks1]

Guess thats why they call it a mirror finish Bob working well though init I’m dead chuffed especially as it suggests the varnishing is close to the finish .

 

Phil

[Phil Winks 1Participant @philwinks1]

Here we go Bob the penultimate coat of varnish is on I reckon. all she needs now is a rub down with 1200 and a bar of soap to polish this coat off.

 

 

 

 

then the last coat can go on. that one will wait for a warm day so it can be done in the shed after I’ve thoroughly dusted it out, and then hopefully no specs will blemish her while it’s drying.

 

the underside will get another coat of paint and one of varnish in the meantime. And the sentries are keeping a close watch for the motor/esc arriving from good old HK.

 

Phil

Edited By Phil Winks 1 on 10/05/2010 20:12:41

[Bob Abell 2Participant @bobabell2]

What a lovely model!……………..All lovely and shiney……..will be nice to see, skimming along on the plane!….eh?

 

Well done Phil

 

Did you notice that in the kit, there are two lengths of dowel which are supposed to be stuck on the model stand………..over the holes?……………….I couldn`t sort it out!……..any idea what the idea is?

 

Bob

[Phil Winks 1Participant @philwinks1]

Thanks Bob. On the subjectof those dowels. Best I can make out  is they should be painted blue and fixed in a curve to sort of represent a wave. Some Danish idea of style no doubt.

 

Phil

[ashley needhamParticipant @ashleyneedham69188]

Gosh Phil, I would hesitate to say that you have achieved the pinnacle of shinyness as epitomised by THE Barrelback, but my word its very close even now. Please do not use flash when taking pictures as you may achieve temporary blindness !

 

I can see this flying along….I think mainly due to the single prop, rather than anything else.?

 

Ashley

[Phil Winks 1Participant @philwinks1]

Thank you Ashley !! as for the single prop helping it fly along I think the enormous power to weight ratio (app 150W/lb) may also have something to do with it. however lets not count chickens eh? it may yet turn out to be a lead balloon! I doubt it, but it may!

 

Actually I need to check that power to weight figure  I may have that wrong.

 

Phil

[Phil Winks 1Participant @philwinks1]

For those of you paitient enough to be still watching some progress is about to happen to this “Lil old Lady”

 

Today the 1st of several pieces of bling for her motor bay arrived

 

This is (dry fitted) the watercooled motor mount and according to my email inbox the couplings are to be posted tomorrow now I’m just waiting for the bty, esc, motor, cooling jacket, and cables etc to come from cornwall and by the new year we should be looking at a fairly quick boat, at last.

 

Phil

[Bob Abell 2Participant @bobabell2]

Hello Phil

 

Nice to see you back in the Slo Mo harness, so to speak!

 

I like the water cooling mount……that`s a fine start to the motor drive!

 

What motor have you selected?……Any pix?

 

Pity about the big freeze at the Mo, but it`ll stop the motor overheating, hey?

 

In the meantime….A Merry Christmas and a Happy New Year to one and all!

 

Bob

[Phil Winks 1Participant @philwinks1]

Here ya go Bob

 

the motor

its water jacket

the couplings

and the esc complete with reverse function

While the esc is a seaking 35A it’s not coming direct from swang hobby but via a guy I know who imports them direct from HK and does a better deal and keeps a small stock so del is usually much  better.

 

The Bty’s are to be a pair of 2S 1P (7.4v) LiPo rated at 2300Mah and 25C wired in series giving the motor 14.8v which at 900kv means a theoretical shaft speed of 13320rpm. should be plenty quick enough

 

The couplings are a tad pricey at £11.98 + VAT but are good to about 31000rpm so are well up to the job

 

Phil

[ashley needhamParticipant @ashleyneedham69188]

Phil, any particular reason for an in-runner?? rather than an outie. The outies seem to have a generally larger diameter and hence (one assumes) more torque and appear to be more common especially in the lower Kv ratings….or have I forgotten a post detailing why in the last 14 odd pages ! My informant said that the small in-runner for my latest project would normally be used with a gearbox and so it has a very high Kv rating (3600) . Not that its powering a water prop mind you, but it beats me how the bearings last any length of time at 36,000 Rpm….

 

I like the advert…”The best ESC in china”. I would read that as the most used and thus best ESC in China, but I dont suppose there is a lot of model boating in the country?? or can Colin confirm some Chinese M.B subscribers exist!

 

I am amazed by the water jacket AND watercooled motor mount….does the mount clamp the motor or is it bolted on at the front as normal?? Its amazing what you can get nowadays…water cooled mounts as well as jackets….my word.

 

Cant wait to see it fly!!!

 

Ashley

[Phil Winks 1Participant @philwinks1]

Hi Ashley some interesting and valid questions there.

 

1st the reason for an inrunner is to allow cooling of the motor with the jacket (canned outrunners are rare) also please note you are correct an outrunner of the same dimensions would have more tourque however I felt that the 384W this 26A motor can supply at 14.8v would be ample power.

 

As for the longevity of the bearings, my experience is that brushless motors tend to be better engineered than brushed and the sealed ball races used are usually well up to the job in hand.

 

the motor fixes to the face of this mount (there are clamp versions available) and the slots for the fixing screws allow a variety of different diametre motors to be used, this one will allow a motor with fixings between, 14 & 25mm apart, and if it has a boss this can be up to 12.7mm wide. The max diametre of the motor can be up to 56mm. Basically 380 to 540 size motors in brushed terms.

 

Hope this answers your questions and merry Xmas Phil

[Rick DevonshireParticipant @rickdevonshire]

Hi Phil,

Have been away from modeling for a while and must get back to boat building when the weather lets me use the workshop in the garage again! 

Your Slo Mo is looking good, a real craftsman job. 28Amps is some current – what batteries do you plan to use?

cheers,

Rick

[Phil Winks 1Participant @philwinks1]

Hi Rick they’re a pair of loong max tipple 5c charge 25c disharge LiPo’s 2s1p (7.4v) 23000mah wired in series to give 14.8v and capable of handling a total max discharge of 57.5A (25 x 2.3A) so over double what I’ll ever ask of them. Yes discharging at 26A will flatten them in 6mins but that is the max they’ll be asked and who runs even a boat like this at full throttle 100% of the time. to be honest it’ll prob get on the plane at 1/4 throttle 1/2 max and 6 mins of tearing the pond up at those speeds is as much as anyone could cope with. These boats are after all built for speed not long runs.

 

Phil

[TelstarParticipant @telstar]

Hi Phil,     The quality of build is exceptional.  

 

 You have obviously researched you choice of motor battery etc quite deeply, so be sure to use adequately rated wire for your battery connections,   4mm or 12 guage copper wire is normally rated 25A  but for short periods of use ie less than 10Min would be ok, but there is a lobby in the fast electric camp (no Dave M I’m not going scouting )  that brushless rigs are suseptable to wire size/length   look at artical 

http://www.astecmodels.co.uk/brushless-motors.htm

 

Looking forward to seeing Slo Mo  acheive L E O      (low earth orbit)

 

Cheers Tom

[Phil Winks 1Participant @philwinks1]

Hi Tom and thanks for the input! All good stuff.

 

However I have found that as long as one adds no further wire than is supplied attached to the components then the problems you warn of are unlikely to occur, to this end the ESC is always mounted adjacent to the motor and the bty’s well within reach of the esc. also I try to plan a power train with an esc that has a rating well (at least 50%) above that of the motor and install a motor that has a rating at least 20% above what I expect to be asked of it. and bty’s that can supply approx 100% more Amps than required. This ensures that no one component is ever worked to capacity.

 

in short I expect to need 20A from the motor, hence a 26A motor, this dictates a need for a 39A esc. 35A seems close enough especially as the burst current on my chosen one is 70A. and add to this 2300Mah 20C btys, 20 x 2300 = 46000Mah (46Amps) and nothing is being stretched so to speak, also running the bty’s at 1/2 capacity gives a longer run time.

 

As for  LEO well true scale speed for the Slo-Mo is approx 14mph (1/12 of 178mph) and if she’s on the plane at that speed I will have achieved the goal of producing a scale craft, however the power calculations done by a freind on RumRunner suggests she’ll top 30mph and to be frank that scares me a little. I gave up model flying for a reason LOL

 

Phil

 

 

[Phil Winks 1Participant @philwinks1]

Just a quick note to wish all of you following this thread a prosperous new year.

 

Hopefully it will be filled with clear skies and fair winds for many a happy sailing day.

 

 

And maybe the post office will finally get its act together. 3 days ago the guy supplying the running gear for the “Lil Old Lady” posted me 3 similar size parcels from Cornwall by recorded delivery, and in their infinite wisdom the Post office decided I only needed 1 today, and the rest next week some time. (Boy I could spit) So it looks like another delay getting her on the water.

 

Phil

[Phil Winks 1Participant @philwinks1]

All the running gear, bty’s etc finally arrived a couple of days ago and since I’ve been spending the evenings in my (now heated) shed.

 

A gaff on my part (got the wrong ESC) has seen me downgrade the bty from 4s1p (14.8v) to either a 2s1p(7.4v) or 3s1p(11.1v) bty. the power calcs suggest that because of the weight loss both options should still give adequate performance with the higher Voltage only just out performing the 7.4v option due to a hevier bty weighing her down.

 

Any way its all installed and programmed and (here’s the rub) now it has to wait, till after I get back from my eldest daughters 30th birthday party in yorkshire this weekend, for its water trials.

 

So here’s some pics of the installation to be going on with

 

The bty in the pic is the 2s1p (7.4v) option and is ofsett to acheive lateral balance.  The Longditudal balance point is app 30mm aft of the sponson rear face. (app 10% of the afterplane length) total weight is a sprightly 1.3kg.

 

The rubber band hooks to the cowl to keepit on.

 

Can’t wait to get her on the water

 

Phil

Edited By Phil Winks 1 on 06/01/2011 18:38:59

[Bob Abell 2Participant @bobabell2]

Hello Phil

 

You`re nearly there!………But you`ve got a bit of a wait on your hands!

 

If your lake is anything like ours, we are frozen solid at the moment!

 

Can you show us the water scoop arrangement, please

 

Bob

[Phil Winks 1Participant @philwinks1]

Our daytime temps have been up near double figures most of the week Bob and our pond is well thawed.

 

the water scoop is visible in thisphoto and the outlett is just above it

 

Phil

[Bob Abell 2Participant @bobabell2]

Thanks, Phil

 

Looks rather a sharpish corner for the water to get round?

Have you got a visible outlet pipe to prove the system?

 

Just curious……Bob

[Phil Winks 1Participant @philwinks1]

Allready proved Bob the outlet is visible just under the fin also the internal pipes are trnsparent enough to see the water traveling through at start up. even in a static bath test the system filled in secs.

 

As a back up the ESC has “overheat” protection that reduces available power so even if a leaf blocks the input I’ll be able to get it back to the bank with no damage.

 

as an added safeguard I’ve fitted a “LiPo low volt alarm” that triggers at 3.3v on any cell and this presumpts the ESC that triggers low voltage shut down at 3.2v X cell count so no danger of over flattening the bty’s

 

Hopefully I’ve covered all the bases

 

Phil

[Bob Abell 2Participant @bobabell2]

Come on, Phil

You`re progress report is well overdue?

Bob

[Phil Winks 1Participant @philwinks1]

Hi Bob,

Works been manic, I’ve been working most saturdays and one sunday. Hopefully I’ll get chance this weekend to try her out, if the pond hasn’t frozen again as the weathers taken a turn for the worse this week with temps well below freezing most days. However it did go up yesterday afternoon so fingers crossed eh

Phil

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