Slo mo Shun

[Phil Winks 1Participant @philwinks1]

some nice work on that site Bob have you spotted my new thread yet  and here’s hoping the weathers kind to you next tuesday

 

 

 

Phil

Edited By Phil Winks 1 on 25/03/2010 17:54:42

[Bob Abell 2Participant @bobabell2]

Here is latest development mod……………The Snowplough Deflector!…………And to cut a long story short for the sake of newcomers …..(If any)……..because the motors are struggling to get on the plane……..due to the extra wide bow wave………….the mod is designed to split the wave sideways

 

Here`s fingers crossed for next Tuesday………………..Bob

[Phil Winks 1Participant @philwinks1]

Looking good Bob fingers crossed for tues I’ll be watching to see how well it works.

 

 

phil

[Bob Abell 2Participant @bobabell2]

This is what we are trying to achieve!………………ie…….No bow wave!

 

Looking at it now…….We`ve no chance!

 

Bob

[Phil Winks 1Participant @philwinks1]

I still find myself smiling when I see that picture! Probably more so now I know the history of this brave little boat. That certainly is well up on the plane Bob I think you’d have to go brushless and 48V!!!! And that would prob involve a remortgage or lottery win

 

 

 

Phil (the silly heads out now)

[Bob Abell 2Participant @bobabell2]

This looks like a worthwhile improvement?

 

Fully adjustable Elevators……..to prevent the tail end getting too low and will also restrict aeration of the props………Roll on Tuesday!

 

Bob

[Phil Winks 1Participant @philwinks1]

thats the one Bob! nice job

 

Phil

[Phil Winks 1Participant @philwinks1]

You may have seen this already Bob! A little smaller than yours but here’s what brushless can do for it. 

 

 

You tube link

 

 

Phil

[Bob Abell 2Participant @bobabell2]

Yes, I have seen it before……….Those brushless motors are so quiet, they sound quite harmless!

 

Bob

 

 

[Bob Abell 2Participant @bobabell2]

What d`yer reckon, Phil?

 

I`m calling these….”Running boards”

 

They`ll look very nice all veneered, with an Ali trim!

 

Bob

[Phil Winks 1Participant @philwinks1]

Looks good mate! Are they flared into the chine underneath? To help lift the stern.

 

 

Phil

[Phil Winks 1Participant @philwinks1]

On the subject of brushless motors, it’s the lack of brushess and the fact that most are really well engineered that makes them so quiet.

 

Phil

[Phil Winks 1Participant @philwinks1]

Some results here from my search for the secrets of the Slo-Mo.

 

   I’ve found an Interview with Ted Johnson, the designer and pilot of her, and thought this passage might be of interest when it comes to setting up the trim.

 

   “So it can be seen that she is not an exceptional boat as far as size, power, or appearance is concerned. In fact, it has the appearance of a conventional Gold Cupper. Her speed relies solely upon the development of its planing surfaces, its balance, and the efficiency of its propulsion unit. The weight distribution is different from any of the other Gold Cup contenders. We put the boat in a sling and moved the engine and the gas tank until it balanced correctly. Her stern comes out of the water and she planes like a 135 cubic inch class, which for its horsepower is the fastest boat built.”

 

   There’s loads more here

[Bob Abell 2Participant @bobabell2]

Thanks Phil…….Very interesting

 

I like the idea of it being clear of the water…..on the plane!

 

Bob

[ashley needhamParticipant @ashleyneedham69188]

Bob. Even if the the splitter thingy you have fitted works in clearing water at low speeds, it will only hinder obtaining those important higher speeds (eventually !!!)

 

The Back is very low, and an alternative mod may be to have a completely flat rear end, rather than the chamfered back as at present, This will add bouancy and not give the  trough in the middle near the props. To this end, have you considered using sculptural blue foam (it comes in other colours) . This is easy to cut and fairy stiff and does not crumble like expanded polystyrene….and can be used to experiment with the bottom of boats, being held in place with wire or pva etc and can be resined after to become permanent, if successful.

 

It means you alter the shapes very easily and quickly, or even take several rear/front ends to the pond side and try them all out.

 

I like the look of the adjustable flaps, but as another measure how about fitting a full transom flap several inches deep.? this I believe extends the effective length of the boat when under way and pushes the c of g forward (is that right? I think thats the theory)

 

I still think experimenting with props would be worthwhile despite that in theory they are the ones to match the motor and so on…

 

 you are on the best bit now Bob… getting it to work is the trick-keep a stiff upper lip!

 

Ashley (has experience of less than standard models not behaving as intended)

[Bob Abell 2Participant @bobabell2]

Thank you Ashley for your always welcome advice.

 

The splitter should not hinder the boat too much…………..If we get somewhere on the plane…….the splitter is almost clear of the water!

 

As for modifying the rear end………No b*****y chance!…………..You mean, mess up all that veneer?

With a bit of luck, the new outer running boards may support the back and the new elevators should really have an effect too!

 

I shall just carry on going to the pond every Tuesday to test out the latest brain wave, then come home and dream up another…….after a few whoskies of course!

 

All good fun at the Mo……………..Bob

[Phil Winks 1Participant @philwinks1]

Hi Bob there’s a thought proccess going on in my head (now there’s a suprise) regarding the power/weight of her. just so I get it nearly right before I open the old gob.

 

remind me please the total weight and the weight of the bty’s. also did some one not tell you what sort of power in watts/HP to expect from those motors on 24v. I’m sure I’ve seen that in the thread somewhere!

 

 

Phil

[Bob Abell 2Participant @bobabell2]

Sorry Phil…….My reply has found it`s way into your Slo Mo thread

 

Another senior moment……Bob

[Phil Winks 1Participant @philwinks1]

Not a problem Bob got it either way.

Cheers I’ve a few calcs to do but to be honest I think the L word will be the answer, and to be honest I can’t see how that can be achieved with your slomo.

However it is a warning for me to keep things light looking like I need to be under the Kilo (2lbs) by a good margin to ensure a crisp performance. More on  this later.

 

 

Phil

[Bob Abell 2Participant @bobabell2]

Hello Phil

 

What`s the “L” word?

 

Your boat under a Kilo?????

 

Please explain…………….Bob

[Phil Winks 1Participant @philwinks1]

“LIght”  Mate

 

I’ve got a feeling that yours is just a tad on the heavy side compared to the originall at 4400lbs 1/6th of that (cubed down of course ie: divide by “x” 3 times to allow for length, breadth and depth) is 20lbs

 

So I was trying to find out if switching to a lighter bty could save you 6lb! However on reflection you’ve added volume giving the same effect so prob not necc now.

 

 we shall see on tue eh?

 

The same sums at 1/12th give me a target weight of 2.5lbs so getting it to a kilo (2.2lbs) should help ensure success. because like you I’m not worried about mental speed but it would be nice to see it planning at 14.9mph (1/12th of the 178mph water speed record) and to do that it needs to be light light light (according to my pet fast electric fan)

 

Phil

[Bob Abell 2Participant @bobabell2]

Thank you, Phil……………….Phew!……..Thought you had some bad news for me!

 

I will be quite happy if SloMo “looks” fast…ie…Plenty of noise and spray etc…………..Like you see destroyers dashing round the lake at well over scale speed

 

Your calculations don`t bear in mind, the amount of power required and available etc

Having a the correct scale weight is not the full story!

 

Can`t see you getting anywhere near 2.2 lb…………..The batteries will be way over that!

 

Just for interest…………..What does your model weigh now?

 

Bob

[Phil Winks 1Participant @philwinks1]

I agree there Bob the other thing it doesn’t take into account is the fact that the water/air density can’t be scaled down so scale power doesn’t work. however scale weight is a good maximum to work to if possible as often over scale power isn’t to difficult to achieve. well at the smaller scales anyway bit harder it 1/8th and above I reckon.

 

As for mine well its still on the base board so really heavy, and bty weight is an issue, thats why I’m seriously considering dusting of my aircraft lipo’s that are in storage.

 

I reckon 11.1v 2500mah (3 cells) should weigh about half, if not less, Than 8 sub C NiMh’s and I’ll have more volts to spin a decent motor.

 

Phil

[Bob Abell 2Participant @bobabell2]

Morning, Phil

 

All charged up and ready to go!

 

Weather not too good, but still going anyway!

 

The batteries, all took nearly two hours to top up and got quite hot…….Any problem, here?

 

Hope you are winning with those tricky plywood pieces!

 

Bob

 

ps….Like your para`s!…….Big improvement, eh?

[Phil Winks 1Participant @philwinks1]

Hi Bob hope it went ok Mate.

 

Those Batterys are quite big (in Mah terms) and so will  have a high ish internal resistance so yes expect them to get good and warm when charging. esp at higher amps.

 

as long as they’re not so hot you can’t pick them up you’ll be safe. if you feel they’re getting to warm then charge at a slightly lower amp setting.

 

however the recomended fast charge is usually 1C which is simply the Mah figure divided by 100 to give Amps.

 

most will be safe however up to 5C and some even up to 10C (caution advised at these levels though). Did a data sheet come with them?

 

The esc for my lttle speed boat arrived today so that’ll be strutting it’s stuff on sunday weather permittng.

 

 

Phil

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