Slo mo Shun

[ashley needhamParticipant @ashleyneedham69188]

 Bob…dont they make a 24v Bobs board????      Ashley

 

 

 

[Phil Winks 1Participant @philwinks1]

Hi Bob sorry to hear about the potentially duff P98 I take it they’re both running on the throttle channel and one of the RX plugs isn’t reversed

[Dave MilbournParticipant @davemilbourn48782]

the potentially duff P98

 

Point of information, chaps – we don’t sell duff speed controllers. Every single one is tested before despatch.

It’s interesting to note that over 50% of those which are returned for repair actually do work without anything being done to them. Of the remainder, the problems are usually the result of either reverse-polarity connections; working with a battery in circuit and shorting something out, or overloading the motor and blowing the power FETs. I’m taking bets on the problem with Bob’s #1 unit………………..

 

DM

[Bob Abell 2Participant @bobabell2]

Hello Dave and chaps

 

I was so sure the P98 was faulty, I would have put money on it!……………And LOST!

 

Had a close look at the Rc connections with my reading glasses on for a change and the motor conns were in numbers 2 and 3……and that`s where the fault was!

 

More apologies, Dave…………..Sorry old chap

 

Now where`s the Yellow Pages………Mmmmmm…………Ah!…….Specsavers……….Zzzzzzz

 

So, it`s full steam ahead on Tuesday……..Whoopeeeeeeeee!

 

Blind Pugh

[Phil Winks 1Participant @philwinks1]

Hello Dave I must apologise as it seems that you misunderstod  my earlier post.

 

quote

“Hi Bob sorry to hear about the potentially duff P98 I take it they’re both running on the throttle channel and one of the RX plugs isn’t reversed”

unquote

 

At no point can I make that read “They sold you a duff P98” I really was asking Bob to check that he hadn’t inadvertantly miswired it into the boat.

 

Honestly never meant to cast any aspertions as to the quality of the equipment you make and sell. After all we all know it’s good kit.

 

humbly Phil

[Dave MilbournParticipant @davemilbourn48782]

Phil

Sorry for being a tad prickly there – we’ll correspond about that some other time, maybe.

I pretty much guessed what the problem was anyway………………..    ……and I’d have won my bet!

Incidentally, the figures I gave about the proportion of “faulty” units which turn out to be OK were pretty accurate. I’ve never compared notes with any other manufacturers, though.

Hard-hats for Tuesday, then?

DM

[Phil Winks 1Participant @philwinks1]

No worries Dave I admire your passion for your products. As for You Bob and plugs in wrong sockets I’m a little confused as to how it happened! surely the 2 ESC’s are wired via a Y lead to the throttle channel or has your RX got 2 throtle channel outlets ?? Either way best of luck for the trials tomorrow all fingers and toes crossed for you.

 

Phil (enjoying the sunshine painting a boat  it just don’t get any better)

[Bob Abell 2Participant @bobabell2]

Thanks a lot, Phil

 

I was originally using a mini Rc with three channels……..So without thinking, I used Ch1 for rudder…….with 2 and 3 for the motors

 

Since I`m using the twin stick Navy Tx……….I needed channels 3 and 4!……..Yet another Senior Moment!

 

I did the same daft trick on Jeanie Deans at War……..With the right and left paddlewheels

 

If it wasn`t for you, Matey, reminding me to check the Rc sockets etc………I would have sent the so called faulty ESC back by now by now!!!!!!!……………….You really saved my neck there, pal!………that would have been some egg on my face!………..Dave would have gone berserk!

 

Looking forward to tomorrows` test run…………….Those MMB 900 motors on 24volts are…………………….AWESOME!

 

For ref, I`m using Dip Sw2 …….on

 

Watch this space

[Phil Winks 1Participant @philwinks1]

Ok Bob just to clarify on this “Twin stick navy” tx (not a system I’ve any experience with at all)  are chanels 3 & 4 mixed to respond to one stick or have you got the throttles on two seperate sticks??

[Bob Abell 2Participant @bobabell2]

Here yer go, Phil

 

Futaba …………………………..Navy F-14

 

Twin sticks on the left for independant control for two motors….or two paddlewheels

 

A nice toy……………..they can also be used for steering, by messing with the prop speeds

 

Bob

[Phil Winks 1Participant @philwinks1]

Now thats the sort of thing I’ve been looking for I wonder do they make a 2.4ghz set??? cool piece of kit I’ve actually asked the question “does anyone make a tx specifically for boats?” and up to pres this is the 1st proper answer. Now your going to tell me it’s out off production.

[Bob Abell 2Participant @bobabell2]

Ha! Ha!…………………Don`t know if they are still being made these days…………Mine are about five years old now

 

Bob

[Phil Winks 1Participant @philwinks1]

Thats just the story of my life Bob always just to late. my guess is they’re not an item that turns up on the secondhand market too often. I’ve always been extremely cautious of 2nd hand tx’s anyway so I guess it’s going to be the 6ch 2.4 aircraft set I’ve had my eye on.

 

Best of luck with the sailing today looking forward to hearing/seeing the results.

 

 

Phil

[Phil Winks 1Participant @philwinks1]

Hmm just googled that TX westbourne have them  but so out off my price range  some 5 x what I expect to pay for my next TX. Lovely system though the level of expandability up to some 100+ functions must make it just about the only TX you’ll ever want.  just a shame they don’t appear to make a 2.4ghz set. still it’s not a perfect world is it.

[Bob Abell 2Participant @bobabell2]

Here we go boyz!………………….Got the car packed…………The sun is shining on the Righteous!………………….Going ……”Over theTop” …….at zero hour!………..10.00pm

 

Tin hats at the ready!……………………….Bob the Fearless

[Bob Abell 2Participant @bobabell2]

The boat was very nice to handle……..The roar of the engines was excellent……..Very impressive………..It was nice to see the driver battling with the steering wheel

 

But it was pushing too much water and couldn`t get on the plane!

 

Someone said the props were cavitating and another said the props were oversize.

 

Would a smaller prop make much difference?

[Bob Abell 2Participant @bobabell2]

You can see the water being pushed ahead of the boat here……..A bit like the Severn bore at times!

[Bob Abell 2Participant @bobabell2]

The model looks heavy in the water at times

[Bob Abell 2Participant @bobabell2]

In the pits to move the batteries aft………Didn`t make much difference actually

 

Somebody suggested “ripple strips” on the big flat areas to break up the suction effect

 

I`m open to any suggestions

 

Bob

[Phil Winks 1Participant @philwinks1]

ripple stripes sound a good idea Bob but also some plexiglass over that void inbetween the sponsons might help. The trouble with scaling a boat down is we cant scale down the effect of water, and that void might just be too hydraulically effective at this size.

 

Otherwise it looks like  all round.

 

The argument of “cabvitating” props has been discussed elsewhere on here and in the “noggsund” build article and to  be honest the forces involved to create true cavitating where the prop creates a vacumus void in the water are huge. most likely is they are areating ie sucking air in from being to close to the surface. however are these not surface piercing props you have? The back end does seem to rise well, so perhaps an even further rearward trim might help and if you use smaller (say 10%) props they will turn faster due to the lighter load and this may also help. Did you try turning the dip switch that allows extended throttle travel on/off as if its set low you may possibly be not getting full grunt altghough from graphs its possible not more than an extra 10% travel Dave will tell you more on that point I’m sure.

 

PS One point of interest would be a comparison of time spent running andhowmany Mah  go into the batteries when you re-charge them

 

Phil (pleased for you Bob)

 

Edited By Phil Winks 1 on 16/03/2010 23:09:55

[Phil Winks 1Participant @philwinks1]

Another point that occurs is if you seal some off  that void off you will increase displacement making it sit higher at the front to start with negating the need for extra ballast at the rear.

 

 

Phil (in problem solving mode)

[Bob Abell 2Participant @bobabell2]

Good morning, Phil

 

Thanks for your suggestions

 

I suspect, the biggest culprit being the large void underneath and the weight of the bulbous nose section

 

Looking at the prop chart, the present prop is 54 dia and suitable for a 15cc engine, the next size down is a 50 dia suitable for a 10cc engine………….So I`ll try two of these

 

Forgot about the dip switch option…………..but it would have been difficult to reach at the time

 

Before I close…………..It may be of interest, that four of our members can`t find the Forum section on this website………………..There must be hundreds more, in the same boat……..No wonder, comments are sparse?

 

Bob

[michael kemishParticipant @michaelkemish72883]

Hi Bob,

I’ve been folowing since day one.

I always have to hit the “refresh button” (top right-ish of my screen) to get the latest postings. (in any thread)

How about bigger motors?

Mick.

 

 

[Bob Abell 2Participant @bobabell2]

Hello Michael

 

As far as I`m aware…………….there are no larger motors avaiable in the modellers world

 

Can`t be bothered with the windscreen wiper etc approach

 

If you look in…….. “your account”……….You will find an option to tick,  that sends you to the latest forum posting

 

The refresh button is F5

 

Thanks for your interest over the passed 10 months……..Bob

[Phil Winks 1Participant @philwinks1]

I tend to agree Bob those motors are ample. And that void is definitely a prime suspect. My thought with Plexiglas was to create skin along the bottom just above the bottom of the hull (3/5mm) and then up the back at the rear of the sponsons to completely enclose most of the void, as I suggested earlier if this level of water is excluded the buoyancy of the front end of the boat will be improved with no significant weight gain. I suppose Lite ply or similar could be used, just that plexiglas/perspex would remove the need for more paint so shortening the modification time. trying a smaller prop would be indicated if the time on the water was short compared to the amount of Mah required during recharge. as this would suggest that the motors are working hard to achieve the speed they do thus draining bty’s quicker (smaller prop = lighter motor load = higher revs for same effort. some change in thrust will occur but it is possible that the higher revs may offset this somewhat possibly even resulting in higher thrust if the props are grossly oversize).

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