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Author Topic: Newbie fast electric Mono 1 build  (Read 12932 times)

PeachyPM

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Re: NEWBIE FAST ELECTRIC MONO 1 BUILD
« Reply #25 on: December 31, 2015, 06:58:28 pm »

Quick last post of 2015, the boat is finished!!!!!
Today I ran a full test of the electrics, bound the RX, programmed my TX with slightly reduced rudder movement (80%) and programmed the ESC.
Then on to a bath test to see if she self-rights. She sits nicely with just the correct amount (I think) of port list whilst stationary.
 I needed to add 10g of lead up the flood chamber and a further 5g of lead inside just to port of the prop shaft just to re-balance the centre of gravity at approx 210mm from the transom.
I made a small video of the self righting which I might have to post seperatly.
All that's left to say is Happy New Year & I'll post the results/video of her maiden trials in January.
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IKB

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Re: NEWBIE FAST ELECTRIC MONO 1 BUILD
« Reply #26 on: December 31, 2015, 07:21:49 pm »

Looks good mate  :-))
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knoby

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Re: NEWBIE FAST ELECTRIC MONO 1 BUILD
« Reply #27 on: December 31, 2015, 07:39:56 pm »

Very interesting build, hope it goes as good as it looks  :-))
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derekwarner

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Re: NEWBIE FAST ELECTRIC MONO 1 BUILD
« Reply #28 on: December 31, 2015, 08:55:23 pm »

Hey peachie...this is a super tidy build with a mix of high strength composite materials and hardware  :-))  and you have documented this well for us to follow

Not rivet counting, but for you records, the ballast block you nominate is 10gm of lead, however as show is stamped 10 Zn [lead is approx. 60% heavier than zinc]

Happy new year this 1st day of 2016........& looking forward to seeing images of her on the water O0................ Derek
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Derek Warner

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PeachyPM

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Re: NEWBIE FAST ELECTRIC MONO 1 BUILD
« Reply #29 on: December 31, 2015, 10:10:03 pm »

Cheers IKB & Knoby, it has been an enjoyable 1st FE build.

Derek, thanks for pointing out the weight labelling, schoolboy error on my part & of course I should have pointed out the reason for the use of zinc over lead when a weight is positioned in a place that has direct contact with the water. It's because at our lake we have it stocked with carp to keep the weeds down & as we all now know, lead isn't very good for wild life.

Are you guys down under now in 2016? We've got 2hrs to go and I'm getting the "look" from the missus!

Hope you all have a great New Year! :}
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derekwarner

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Re: NEWBIE FAST ELECTRIC MONO 1 BUILD
« Reply #30 on: December 31, 2015, 11:21:33 pm »

Peachey....... back in post 1, you mention the following......

'P.S. Re "the first rule"; the motor and prop in the photo’s won’t be the ones I’m racing with…but I will give ball park details to help with first timers who might want to get involved' .....however I cannot see any reference to the earlier or final motor sizing

You also mention the 10gm of ballast to offset the motor torque effect

These brushless motors have considerable power & hence torque, however your actual propeller shaft appears to be in the slender region of 2.5 mm diameter....did you do the calcs. on the ballast positioning & requirement to counter the torque?

The other point to consider is that the torque moment applied is proportional to motor RPM, so will the vessel not suffer from a varying list to port :o, dependent on the vessels speed?............Derek
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Unsinkable 2

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Re: NEWBIE FAST ELECTRIC MONO 1 BUILD
« Reply #31 on: January 01, 2016, 09:19:46 am »

I'm not really into fast electrics (yet!) but this thread has caught my interest. Well done peachy looks the part :-))
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PeachyPM

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Re: NEWBIE FAST ELECTRIC MONO 1 BUILD
« Reply #32 on: January 01, 2016, 10:29:35 am »

 :-))Happy New year to all Mayhemers! :-))

Merci, unsinkable2.

Hello Derek, thanks for the questions, I'll try and answer them.

1. For motor and prop spec, I've been given lots of advise ranging from 4600kv to 5000kv using a 38mm dia brushless with a can between 50mm & 65mm in length.
As for props, 1.4 to 1.6 pitch, 33mm to 36mm dia. With the smaller props being matched with the higher Kv/rpm. These are with a 2cell 7.4 set up.
My boat has a 33mm prop on it at the moment purely because that's the largest I have in my spares box. My final choice will be dictated by testing, I will be using borrowed props from some of my club mates and then will purchase whatever works.
2. My wire drive is 2.5mm but this has raised a few eyebrows amongst the racers I know, they all use 2mm!
3. The 10g of ballast is being used mainly to assist with the self-righting, although being on the port side (along with most of the heavy hardware) will help with countering the torque.
4. As for torque varying at different speed this isn't really a factor as the boat will predominantly be run flat-out at all times. The biggest problem is going airborne on an opponents wake as this induces a barrel roll which if not completed 360• will end up with the boat upside down.

So in conclusion; I won't know what motor/prop combination I will use or where I need further
ballast  until I've run tests.
Ps I've been advised that building the boat is the relatively quick bit, setting it up for competition is where the real work starts!
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derekwarner

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Re: NEWBIE FAST ELECTRIC MONO 1 BUILD
« Reply #33 on: January 01, 2016, 11:29:10 am »

Thanks Peachy....[finally correctly the spelling...apologies]

1. It is clear that you are progressing in some sort of logical [researched] manner  :-))
2. I find it difficult to comprehend how 2.5 diameter 'wire' drive can transmit this power
3. Is there any allowance for longitudinal [length wrap-up] length reduction due to rotational torque?
4. Without understanding the FE rules & regs, is a straight line start to finish [such as the Campbell/Bluebird speed tests] the criteria over a circular or semi circular like course?

As you will have realised, I too have little knowledge in this FE model subject....however find the engineering interesting

Derek
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PeachyPM

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Re: Newbie fast electric Mono 1 build
« Reply #34 on: January 01, 2016, 01:01:54 pm »

Hello Derek, I'm still very much at the beginning of the FE learning curve and I hope a more knowledgeable modeller might be able to answer your questions.
My reason for the build blog was to try and "lift the vail" a little on the boat building side.
As for torque reduction over the length of the wire drive, I'm not aware of any, I do however know that this does happen with the flexi drive systems that some racers prefer and that are pretty much the norm with the Hydro out-riggers & Catamarans as the hull obviously sits up out of the water and a fixed shaft wouldn't allow the correct prop angle for surface drive.
As for race rules, we compete around an oval/loop course that starts with a 10s mill time to get the boats from the launch jetti, around the last course markers then under the start gantry. The race time from then on is 6mins. We complete 3 races in 1 meet with the best laps and overrun seconds from the best 2 combined.
Here are the links to the UK governing body (MPBA) who use the rules laid down by NAVIGA
For rules & boat classes;
 http://www.mpba-fes.org.uk/
http://naviga.org/index.php/en/
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PeachyPM

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Re: Newbie fast electric Mono 1 build
« Reply #35 on: January 01, 2016, 02:20:48 pm »

As promised, here's the you-tube link for the self righting bath test;

http://youtu.be/XlSm_F3YUnE

 :-))
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Bridkid

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Re: Newbie fast electric Mono 1 build
« Reply #36 on: January 01, 2016, 03:59:44 pm »

Looks good Chris, hope the Carnaby 'breeze' doesn't stop it from self righting.
Cheers,
Ian.
 8)
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PeachyPM

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Re: Newbie fast electric Mono 1 build
« Reply #37 on: January 01, 2016, 04:15:27 pm »

Happy New Year Ian, I'm going to take more weights with me and do so tests near the waters edge I think!
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PeachyPM

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Re: Newbie fast electric Mono 1 build
« Reply #38 on: January 03, 2016, 07:04:58 pm »

Today I completed a couple of tests with my Lindenau Mono1 and at least learnt a couple of things!
Remember this is the first Mono1 I have built and sailed and when I post some links to a couple of videos I won't mind if you have a good laugh!
The result of the test was that I do have a quick boat that gets up on the plane and is well balanced, although the ESC kept dropping out after a 30seconds of full throttle, I'm not sure if this was a programme problem or a doggey ESC. Also the steering was far too aggressive, and when I trimmed the rudder servo down to 40% I found to my cost that slow speed steering was very poor.
Unfortunately I ran out of water and the boat skipped out! Fortunately only minor scratches and some dinks in the prop, the sacrificial plastic bolt in the rudder worked and the turn fin pivoted out of the way just like they were supposed to do!
Here's a photo of the aftermath, I'll post YouTube links latter.
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PeachyPM

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Re: Newbie fast electric Mono 1 build
« Reply #39 on: January 03, 2016, 07:28:35 pm »

Ok so here is the first test, as you will see the turning is far too sharp and at full throttle she spins on her own axis!! Not good, but at least she's balanced and fast, I'm thinking the rudder is to close to the prop so I will be swapping over the bracket latter but for today I just reduced the servo movement so I could at least get a run in!  :}

http://youtu.be/G6B_qbtgGLM
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PeachyPM

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Re: Newbie fast electric Mono 1 build
« Reply #40 on: January 03, 2016, 07:31:14 pm »

And here is the second run with a more gradual build up of speed... But then whilst trying to stay away from some scale chaps, I stupidly ran out of lake! Doh!  :embarrassed:

http://youtu.be/dEGmezRAew8
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Unsinkable 2

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Re: Newbie fast electric Mono 1 build
« Reply #41 on: January 04, 2016, 01:33:04 am »

Good for you Peachy, you sorted the problem and are big enough to show your mistake. That aside it looks really fast. When I get around to building an FE it's this thread I'll be referring to. Well done!   U2
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PeachyPM

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Re: Newbie fast electric Mono 1 build
« Reply #42 on: January 04, 2016, 07:12:43 am »

Cheers Unsinkable, it was fun...if a little embarrassing! My son had stopped filming so you don't here the big cheer from my club-mates in the background! %%
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PeachyPM

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Re: Newbie fast electric Mono 1 build
« Reply #43 on: January 08, 2016, 05:56:23 pm »

Hello all, so after a long & helpful discussion on the "M section discussion group"  https://www.facebook.com/groups/679193992180229/   (M section is a reference to NAVIGA's section reference for motorized models)
The chaps on there were very helpful and not at all condescending even thou my video of my first test left a lot to be desired!
So here's the list of what has been suggested I change;
1. change the motor from a 36mm can to a 28 or 29mm as the 36 has way to much torque which just flips a lightweight boat like this one.  :embarrassed:
2. move the servo nearer to the transom to help with reducing any flex or flop in the steering.
3. test the servo for "glitching". I've done this, it does twitch at full power so I will be replacing this servo.
4. replace plastic servo arm with an aluminium one.
5. replace or strengthen the rudder linkage to reduce flex
6. move the center of gravity to 28% of the hull length from the transom (195mm as apposed to the 220mm which I have)
7. angle the bottom of the rudder forward by 1 degree to help keep the bow up (I inadvertently had it 1 degree the other way which would contribute to keeping the bow down and therefore digging in during turns)
8. replacing the swept back turn fin (apparently this style is mainly used on riggers and cats again to keep the bow down, I used it 'cause it looked good!) with a square fin.  :embarrassed:
9. move the "kill loop" from the transom to the top deck as some if not most clubs would not allow this configuration to compete. I had only put it where I had because I had seen it on another boat & thought it looked neat!  :embarrassed:
10. and of course finally fill & make-good the scratches it had received jumping out of the lake! (I know it will likely get more during a season but you might as well start tidy!)  O0


This should keep me busy for a while, I'll post pictures when complete then have another go at testing!
P.s there were other suggestions, but these made the most sense and seamed a lot more practical to complete.

In the North; http://www.ampdraggers.co.uk/
In the East; https://ostendospreys.wordpress.com/
In the South; http://www.electrafying.com/ & http://shpowerboats.co.uk/
In the West; http://www.swambc.webeden.co.uk/#/swarm-home/4581722394
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PeachyPM

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Re: Newbie fast electric Mono 1 build
« Reply #44 on: January 12, 2016, 06:37:25 pm »



6. move the center of gravity to 28% of the hull length from the transom (195mm as apposed to the 220mm which I have)




Just a quick post to say my maths was wrong again!
28% from the transom on a boat that is 620mm long would be closer to 174mm  {-)


 {:-{  That's gonna be a task! First I'll try & get everything back as far as possible before I start sticking more weight in this boat.

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derekwarner

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Re: Newbie fast electric Mono 1 build
« Reply #45 on: January 12, 2016, 07:58:24 pm »

Peachy.............I assume the balance point is rather critical.....do you construct a sharp edged hull profile to mirror the hull profile, the gently adjust the fore & aft hull estimated placement until you achieve that pivoting balance & the measure this as the nominated balance point?........... Derek
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Derek Warner

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Re: Newbie fast electric Mono 1 build
« Reply #46 on: January 12, 2016, 08:29:55 pm »

Never having built a FE what I say next may be total nonsense but...... If your balance weight is (just for example) 50g, would it be possible to have a nut or threaded disc on a threaded bar from say 150mm to 180mm. The total weight of the bar and nut or disc being equal to the 50g (or whatever your weight is) this would mean you could spin the balance weight forward or aft 15mm to fine trim the balance point. Or is this  %% {-) {-)
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PeachyPM

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Re: Newbie fast electric Mono 1 build
« Reply #47 on: January 13, 2016, 10:16:20 am »

Hello Derek & Unsinkable,
In answer to your question Derek, I use my boat stand but I tape two 5mm ball bearings on top of one of the up-stands so the boat is just sitting on the two spots at the back with the bow resting in its cradle. I then slowly push my boat back & forward until it just sits up at the bow so that the bottom of the step & the bottom of the transom are both in line horizontally then I can take a measurement with a small steel rule (see photo, although you cant see the BB's they are there) I used this because the hull changes shape along its length.  ok2


Unsinkable, I've not seen such a devise in use but I guess the principle would work, however I am finding out the the secret to a fast boat isn't just one thing, but the some of its parts, and the ability for the boat to self-right has also to be considered when placing weight so I'm not sure how this would work, it might be more practical on a bigger boat. :-)) 

In the North; http://www.ampdraggers.co.uk/
In the East; https://www.ostendospreys.wordpress.com/
In the South; http://www.electrafying.com/ & http://shpowerboats.co.uk/
In the West; http://www.swambc.webeden.co.uk/#/swarm-home/4581722394
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PeachyPM

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Re: Newbie fast electric Mono 1 build
« Reply #48 on: January 15, 2016, 08:04:20 pm »

Ok, so the next job I've tackled is a hydrodynamic problem. I knew that to help the boat get up on the plane, you need to reduce the "wetted area"of the hull, this is why the mono hulls have steps, I also knew that the sharper the chines were the easier the boat would be released from the grip of the water. I assumed that a nice clean smooth hull would work perfectly as long as the chines, step & transom were nice & sharp....but it was pointed out to me that maybe a contributing factor to my boat running "wet" (not up on the plane enough) could be hollowing under the hull, which apparently works like a hydrodynamic version of ground effect in that it sucks the boat down onto the water surface.
To fix this I first needed to spot any convex hollows in the hull using a metal edge and a back light (see photo) and guess what? I found plenty! :((
so on with the filler, then off with the filler using a very hard and perfectly flat sanding block.
Right...on with the paint!

In the North; http://www.ampdraggers.co.uk/
In the East; http://www.ostendospreys.wordpress.com/
In the South; http://www.electrafying.com/ & http://shpowerboats.co.uk/
In the West; http://www.swambc.webeden.co.uk/#/swarm-home/4581722394
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