Model Boat Mayhem
The Shipyard ( Dry Dock ): Builds & Questions => Lifeboats => Topic started by: kinmel on December 30, 2017, 06:02:59 pm
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To modelers, the outstanding feature of a Shannon is it's extreme maneuverability and performance. It is going to be a big attraction at Regattas etc., especially "dancing" in pairs.
So this topic is strictly about devising ways to remotely control the model, so as to replicate the actual boat's performance. We want to keep this project separate from the "Build" Topic.
Berthon made a video of a real Shannon that shows what we aim to achieve. We have posted a link to it before, but concentrate on the jet drives as it all happens.... https://www.youtube.com/watch?v=mQX7UMR4zLo (https://www.youtube.com/watch?v=mQX7UMR4zLo).
The original Jet Drives are made by Hamilton and they have published a technical pamphlet about the HJ 364 drives, Section 2 concentrates on how the maneuvers are achieved.....
http://www.hamiltonmarine.co.nz/includes/files_cms/file/Product%20Manuals/Obsolete%20Manuals/HJ362%20R1%20A37.pdf (http://www.hamiltonmarine.co.nz/includes/files_cms/file/Product%20Manuals/Obsolete%20Manuals/HJ362%20R1%20A37.pdf)
This Topic's challenge is to control each and every one of those operations from the lakeside.
Join us and help to achieve it.
Other technical data is available here.....
http://www.hamiltonmarine.co.nz/includes/files_cms/file/HJ%20Series%20Brochure%20Eng%202012.pdf (http://www.hamiltonmarine.co.nz/includes/files_cms/file/HJ%20Series%20Brochure%20Eng%202012.pdf)
http://www.maritimejournal.com/__data/assets/pdf_file/0030/856821/HJ-Designers-Manual-Eng-2014.pdf (http://www.maritimejournal.com/__data/assets/pdf_file/0030/856821/HJ-Designers-Manual-Eng-2014.pdf)
http://www.seattle.gov/Documents/Departments/PSCSC/ExamsAndRegisters/HJ364MECControlsManualR1A5.pdf (http://www.seattle.gov/Documents/Departments/PSCSC/ExamsAndRegisters/HJ364MECControlsManualR1A5.pdf)
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may I ask the first question please...........
what is the minimum number of channels on a TX that you envisage to achieve your aims, without going into switchers/mixers etc.
and apart from the 4 main channels on the two sticks normally seen on multi channelled sets, how do you envisage the other two [probable number] channels be arranged......................plus any ideas to the best sets without breaking the bank.
thank you. :-))
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The first question is always the hardest to answer and there is probably more than one answer.
I doubt that even all singing, all dancing transmitters will be able to provide all the necessary control, we will have to see.
Remember just 2 joysticks are capable of combining to provide 25 unique outputs, nothing is analogue anymore.
The biggest problem is doing five or six things at once just to get one particular response and adjusting the outcome in real time.
Even top end transmitters are fairly crude in computing terms, but low cost electronics and single purpose devices should be able to provide the capability boost we will definitely need.
It is too easy to build the Shannon kit and then just sail it serenely around the lake, but is that all you want from a model that will have cost about £1,200 ?
To me and others, it is worth the extra effort and minimal cost to show it performing in all it's glory.
The intention is to design systems that are cheap enough and simple enough for every Speedline Shannon owner to have them. This is not a business venture, it is hobbyists working towards a common goal.
If it was simple, we would not be running this Topic.
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First pre requisite is have jet drives (now in kit form) complete with no missing parts. For now I'll laugh it off {-) and hope it is sorted.
C3PO will I feel be a huge contributor in the handling stakes :-))
Thanks for your super contributions ongoing Alan :-)
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First pre requisite is have jet drives (now in kit form) complete with no missing parts. For now I'll laugh it off {-) and hope it is sorted.
C3PO will I feel be a huge contributor in the handling stakes :-))
Thanks for your super contributions ongoing Alan :-)
C3PO is the driving force, just look at the seven turrets topic !
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Here's my thoughts. Someone please correct me if I'm wrong!
Here's how I'd do it;
Motor speed control on auxiliary potentiometer controlled channels. You could use two seperate channels, but if my thinking is correct, you could actually get away with having both throttles on the one channel without any issue.
Buckets raised/lowered by pushing each stick up/down. Port bucket on the left stick, Starboard bucket on the.... you guessed it.
Steering by moving one of the sticks left/right. Which one you choose is up to you.
With the above control assignments, you could perform the various manoeuvres thusly; (The percentage values are arbitrary - just set as much throttle as you need to perform the manoevure, obviously you don't need to be at full throttle if you're only manoeuvring at slow speed)
(https://www.dropbox.com/s/zh0lg2wlvx3aje0/jetdrivecontrol.png?raw=1)
For things like crabbing in a circle around a buoy, that is essentially the crabbing manouevre, but with slightly more/less bucket. With practice you should be able to perform all those manoeuvres with the above controls.
As for a suitable transmitter, you could use a Turnigy 9X, which comes with 3 potentiometers, you could use the two on the top if you were having seperate throttles, or the one on the front if you weren't (or I suppose you could use one of the top ones if it's easier to reach)
(https://oscarliang.com/ctt/uploads/2014/04/turnigy-9x-radio-transmitter.jpg)
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Here's my thoughts. Someone please correct me if I'm wrong!
Here's how I'd do it;
Motor speed control on auxiliary potentiometer controlled channels. You could use two seperate channels, but if my thinking is correct, you could actually get away with having both throttles on the one channel without any issue.
Buckets raised/lowered by pushing each stick up/down. Port bucket on the left stick, Starboard bucket on the.... you guessed it.
Steering by moving one of the sticks left/right. Which one you choose is up to you.
With the above control assignments, you could perform the various manoeuvres thusly; (The percentage values are arbitrary - just set as much throttle as you need to perform the manoevure, obviously you don't need to be at full throttle if you're only manoeuvring at slow speed)
For things like crabbing in a circle around a buoy, that is essentially the crabbing manouevre, but with slightly more/less bucket. With practice you should be able to perform all those manoeuvres with the above controls.
As for a suitable transmitter, you could use a Turnigy 9X, which comes with 3 potentiometers, you could use the two on the top if you were having seperate throttles, or the one on the front if you weren't (or I suppose you could use one of the top ones if it's easier to reach)
(https://oscarliang.com/ctt/uploads/2014/04/turnigy-9x-radio-transmitter.jpg)
thank you for those great explanations McGherkin.......... could I ask, how many channels does the above tx have in total. thank you.
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just checked the spec.........9 channels, and very reasonable price for what you get.
cheers
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Ridiculous!! ly
cheap O0
https://www.ebay.co.uk/itm/Turnigy-9X-9Ch-Transmitter-iA8-Receiver-Mode-2-RC-Racing-Drone-Airplane-FPV/332488585451?_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D1%26asc%3D20160908110712%26meid%3Dab0e17f2d7ba4f72a715f10b556ba38e%26pid%3D100677%26rk%3D1%26rkt%3D30%26sd%3D332488583139&_trksid=p2385738.c100677.m4598
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£54 delivered from here
https://hobbyking.com/en_us/turnigy-9x-9ch-transmitter-w-module-ia8-receiver-mode-1-afdhs-2a-system.html
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They’re a great radio. I have one for my Tamar.
You can also hack them and put custom software on them if you like, then they become VERY clever!
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Under £42 delivered from Uk warehouse
https://hobbyking.com/en_us/turnigy-9x-9ch-transmitter-w-module-ia8-receiver-mode-2-afdhs-2a-system.html
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I have that Turnigy, I just need to put the sticks back to friction instead of self-centering.
I will try your setup on the Shannon next week.
Moving the throttles up onto the knobs is an interesting idea.
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Great cos I bought the Uk one 👍
I also have a spare backlight as I converted two DX6i recently
Looking at a battery solution for it
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Under £42 delivered from Uk warehouse
https://hobbyking.com/en_us/turnigy-9x-9ch-transmitter-w-module-ia8-receiver-mode-2-afdhs-2a-system.html (https://hobbyking.com/en_us/turnigy-9x-9ch-transmitter-w-module-ia8-receiver-mode-2-afdhs-2a-system.html)
Well that was easy. thanks.....at £42 quid,inc postage, you can't grumble unless it explodes in my hand lol.
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Well that was easy. thanks.....at £42 quid,inc postage, you can't grumble unless it explodes in my hand lol.
:-) :-))
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I have that Turnigy, I just need to put the sticks back to friction instead of self-centering.
I will try your setup on the Shannon next week.
Moving the throttles up onto the knobs is an interesting idea.
You might need to tweak the trims on the transmitter to get that sweet spot of neither ahead nor astern in the middle of the stick travel, but then if you’re using friction rather than self centering then I suppose it doesn’t matter so much. Self centering would make it much easier to find your neutral position though, like a conventional boat once you let go of the sticks, she should stop driving ahead/astern.
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don't know what I'm goin' ta do wi' it though, as I haven't got a Shannon, lol. %% %% {:-{ :embarrassed:
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i used to have 9x's got couple left that are for sale
i now use a Frsky Taranis X9D Plus
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don't know what I'm goin' ta do wi' it though, as I haven't got a Shannon, lol. %% %% {:-{ :embarrassed:
Neither do I! Well, not at the moment anyway... I can't promise anything!
Looking at a battery solution for it
Whoops, didn't see this last night. I know quite a few people go to 3S LiPo, apparently the Dualsky 2700mAh transmitter LiPos fit, but being LiPos you need to watch the voltage reading on the screen to make sure you don't discharge the battery too much.
That said, I haven't bothered changing the batteries, even with a backlight my 9x sips power very gently.
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I have just bought a Turnigy 9X 9 Channel Tranny plus Module, (whatever that is)plus receiver from Hobby King for £36.86,Fantastic value.
[/size]PLUS: tw[/size]o Turnigy 'Bolt' V2 1000mAh 4S 65~130C High Voltage Lipo Packs for £9.89 each
PLUS: two Hobby King 60A ESC A for £13.88 each.[/font][/color]
[/size]I HAD NO IDEA how expensive this hobby can be! [/color]
[/size]I am expecting lots of brilliant ideas but, please, make them as simple to understand a possible.[/color]
[/size]I think I bought a Futaba challenger for over £100 in 1990.
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Neil, come on now.
You have my address.
Just send money!
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Neil, come on now.
You have my address.
Just send money!
I've 3 lifeboats to build before I get to anything that goes like a rocket mate, lol.........no.......was just wondering when you were venturing north of the border.........Lancashire border that is, lol.
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I'll be using the FLYSKY I6X transmitter with a 10 channel receiver, only needs 4 AA batteries to power it.
one switch will change from running speed mode to maneuvering control.
running mode, left stick both throttle, right stick both directions,
maneuvering mode, left stick does port motor and direction, right stick does starboard motor and direction.
buckets and trim tabs controlled automatically.
OH and a KILLSWITCH .
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Sounds great. There's load of ideas coming forward so it will be interesting how many of us swap and change what we fit in light of others trials. :-)
Could be expensive {-)
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Sounds great. There's load of ideas coming forward so it will be interesting how many of us swap and change what we fit in light of others trials. :-)
Could be expensive {-)
Flysky I6X 10 channel on banggood, and other sites, around £45 when on offer.
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I'll be using the FLYSKY I6X transmitter with a 10 channel receiver, only needs 4 AA batteries to power it.
one switch will change from running speed mode to maneuvering control.
running mode, left stick both throttle, right stick both directions,
maneuvering mode, left stick does port motor and direction, right stick does starboard motor and direction.
buckets and trim tabs controlled automatically.
OH and a KILLSWITCH .
That’s exactly what I’m doing with my Tamar actually. I’m also limiting throttle in manoeuvring and disabling the bow thruster in running, all through the radio. Clever stuff!
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I also have a Tamar, the bow thruster only works when motors stopped, the right stick direction then controls the thruster automatically changing over. Looking at fitting active trim tabs at the moment.
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There is certainly more than one solution and a well spec'd transmitter can make it all very easy, but some people don't want to use mixers etc.
There will be some thoughts about it all out shortly and then people can decide what route they want to follow.
McGerkin's "Googley Eyes" option certainly works, but is beyond my ability to control the boat with it.
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Did you try it then kinmel?
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Did you try it then kinmel?
I did set it up on the bench and then ran through all the possibilities and it was beyond my abilities to fully manage the boat.
For example the Turnigy 9X comes with spring-loading on one stick and not the other. In your example that stick needs to be physically held up all the time the boat is cruising and I also need to manipulate both throttles and the steering. I could not keep the throttles working closely together, perhaps others can. Removing the spring would help and adding mixers certainly will.
Your version took us out of the box, development is about looking at all the options and refining the practicalities.
Thanks for your help, keep contributing and comment on other people's efforts.
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Lots of ideas to come...
I quite like the idea of these - control pots on the end of sticks...but they are expensive!
(http://modelboatmayhemimages.co.uk/images/2018/01/04/JetiRCStickPot.jpg)
C-3PO
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I did set it up on the bench and then ran through all the possibilities and it was beyond my abilities to fully manage the boat.
For example the Turnigy 9X comes with spring-loading on one stick and not the other. In your example that stick needs to be physically held up all the time the boat is cruising and I also need to manipulate both throttles and the steering. I could not keep the throttles working closely together, perhaps others can. Removing the spring would help and adding mixers certainly will.
Your version took us out of the box, development is about looking at all the options and refining the practicalities.
Thanks for your help, keep contributing and comment on other people's efforts.
Ah, yes. The turnigy does come with one stick friction out of the box. It's fairly easy to sort though. (or you could take the spring off the other I suppose, but you lose the 'auto stop' when you take your hands off the controller)
You want one of these;
http://rctanksaustralia.com/store/index.php?main_page=product_info&cPath=1&products_id=1 (http://rctanksaustralia.com/store/index.php?main_page=product_info&cPath=1&products_id=1)
And a spring, something like this would do;https://www.aliexpress.com/item/FRSKY-GIMBAL-SPRINGS-FOR-TARANIS-X9D-X9D-PLUS/32461969736.html (https://www.aliexpress.com/item/FRSKY-GIMBAL-SPRINGS-FOR-TARANIS-X9D-X9D-PLUS/32461969736.html)
My method was purely for someone wishing not to use any mixers or anything beyond direct control, of course if you wish to use a mixer it will make things MUCH easier!
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This is what I mean by it could get expensive. I've been buying gear I might never use cos someone comes up with a winner {-) and more spending
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This post is to identify which transmitter controllers are used during each particular manoeuvre and to then work out how to simplify the process with mixers and add-on Modules.
For example, we spend most of our time cruising around the lake and that requires us to control 5 transmitter channels. This project will enable you to mange those channels with just 2 controllers instead of 5.
Controls.
We need a minimum of 5 channels to control the water jets.
We use “controller” here to describe any stick, switch, pot, or slider on the transmitter.
Steering.
Both nozzles are always in unison and on the real boat they work through a steering wheel.
The easiest setup is to put both nozzle servos on a “Y” harness from a single controller.
There is no steering when both motors are stopped, even if the boat is still moving.
Jet Drives.
The jet drives must be capable of operating independently, but while cruising, reversing and at Zero Speed, both jet drives must operate as if one.
At speed, a slight change in either drive’s output introduces “tank steering” and the boat will turn suddenly, no matter what the nozzle steering is doing.
The ESCs ignore transmitter commands to reverse.
Buckets.
The buckets must be capable of operating independently when moving sideways.
What are add-on modules?
A module sits between the radio receiver and the servos, ESCs, etc. and can cause one controller setting to manage more than one function.
They are small, cheap circuit boards and a module may contain a number of boards, or a more complex board.
A module is “fit and forget”, once correctly installed you don’t need to alter anything again.
We bring a module routine into play with a specific controller, each routine has its own.
The Scenarios.
Section 2 of the Hamilton Publication HJ362 Ri A37.pdf gives more detailed guidance of helming techniques, here we are just defining controllers.
Note:- These are Controller defaults when using Add-ons…..
Both buckets work on one controller and are up.
Both Throttles work in unison on one controller (centred)
Steering centred.
Forward Cruising.
Both buckets are up.
Both throttles must work in unison to avoid “tank steering”
Steering as usual.
Ideal control solution - Add-ons default.
The 2 sticks on one gimbal are all the controllers you need.
_____________________________________
Reversing and normal braking during forward cruising.
Close both throttles
Both buckets go down
Both throttles opened slowly until stopped, or slower speed achieved
Steering as Usual
Ideal control solution
Both buckets work on one controller and go down, or to mid-way
Both throttles work on one controller
Steering as usual
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Emergency Stop.
Both buckets down.
Both throttles left open
Centre the steering.
Ideal control solution -
all the above happens when a throttle is moved to the 100% down position.
_____________________________________
Zero Speed and low speed Maneuvering.
Both buckets near the midway position, where thrust is equally shared between ahead and astern. Speed is altered by slightly moving both buckets in unison
Both throttles work in unison to hold boat against tide and are not used for manoeuvring.
Steering as usual.
Ideal control solution
Both buckets work on one controller and are initially at mid-point
Both throttles work on one controller at low speed
Steering as usual
_____________________________________
Moving sideways to Port.
Port bucket is down Starboard bucket is up.
Port throttle slightly faster than starboard Starboard throttle just above idling.
Steering used to keep heading
Ideal control solution
Buckets on separate controllers - Port down and Starboard up
Throttles on separate controllers – Port faster than starboard - Starboard constant
Steering used to keep heading
_____________________________________
Moving sideways to Starboard.
Port bucket is up Starboard bucket is down
Port throttle just above idling starboard Starboard throttle slightly faster than port
Steering used to keep heading
Ideal control solution
Buckets on separate controllers - Port up and Starboard down
Throttles on separate controllers – Port constant Starboard slightly faster than Port
Steering used to keep heading
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Next is to find out how close we can get to these theoretical Ideal control solutions.
To move the development forward, we need our micro-electronics experts and those who enjoy transmitter programming to do their thing now.
The rest of us can continue the discussion and throwing ideas into the ring.
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I'll have to print this out and see if an arduino can control as described.
2 modes: running and manuvering.
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Hi Kinmel,
Spooky - I spent this evening mapping out the jet/bucket/throttle positions to see what the permutations where and then see how they could be controlled.
I will digest your post what looks like a great detailed analysis!
Be interesting to see if we came up with any differences...
I think there are 2 themes emerging of one of control "under way" and "manoeuvring on station"
C-3PO
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Tried to reshape my workings into the same structure as Kinmel.
Now slightly lost the plot so will recheck tomorrow - any feedback (typos & error spotting) gratefully received.
If the system uses "add-on-modules" then as Kinmel has explained the module would sit between the RC RX and the ESC, Servos etc.
This means that we could introduce operating modes where at the flick of a switch the functions on the sticks change to reflect the mode selected.
An interesting project...
(http://modelboatmayhemimages.co.uk/images/2018/01/04/ShannonControl001.jpg)
C-3PO
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Gosh! Wasn't it simpler when you just had a prop and a rudder to worry about?
Makes you wonder about the benefits of modern technology.
Colin
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Gosh! Wasn't it simpler when you just had a prop and a rudder to worry about?
Makes you wonder about the benefits of modern technology.
Colin
When the genius collective come up with the end result it will be an awesome experience demonstrating one.
However if anyone were to ask me to explain how it did what ............... {-)
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Kinmel has agreed to an experiment...
We are going to try and glean some operating data from his Shannon to better understand what is happening when is it on the boating lake.
This will involve mounting a small "data logger" on his boat that will record data to an SD card that can then be analysed/graphed after a sailing session.
Using a real time clock on the data logger and hopefully recording video we can get a better picture of what is happening (map data to video timeline).
We intend to capture:
- Date & time
- Throttle positions x 2
- Bucket positions x 2
- Trim tabs positions x 2
- ESC temperature x2
- Motor temperature x 2
- Using an onboard GPS the speed of travel over the water
- Using a sensor the pitch and roll of the hull
This might help unravel for example if there is a point where the motors are running faster than the water can get through the jets
On the other hand it might be a complete waste of time...
An interesting experiment
C-3PO
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Mind blowing thanks %% :-)
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Gosh! Wasn't it simpler when you just had a prop and a rudder to worry about?
Makes you wonder about the benefits of modern technology.
Colin
How true Colin - but if you delve into the PDF files Kinmel posted about the operating of the real Shannon it comes with some baggage!
C-3PO
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All sounds like ancient Chinese Firework alchemy to me! ;) %)
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Gosh! Wasn't it simpler when you just had a prop and a rudder to worry about?
Makes you wonder about the benefits of modern technology.
Colin
Colin,
That's why the crew have a solid 3 weeks intensive training on simulators and relief boats at RNLI Poole College before their boat arrives on station, and then at least 3 more weeks intensive training on the new station boat and a second relief boat at the station before the new station boat is signed off to the respective station........but, as at Fleetwood in June/July/august 2016, they had the relief and new station boat for 5 weeks working in unison to train the crew...........8 weeks intensive training in all.........and our boat was an afloat boat, so no carriage launch training either.
it'll be interesting to see how long the satellite station of ST Annes just down the coast will take, as the relief boat for carriage launch training is already at Fleetwood ready for when the SLARS Supercat comes second week in January, and apparently the station boat comes on the 28th February........when their extensive boat training begins.
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I was being ironic really. But there is the issue that when you are in a close quarters situation in foul conditions the cox needs to be able to act instinctively to control the boat so the training is indeed absolutely vital. No arguments there.
Colin
Colin
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I was being ironic really. But there is the issue that when you are in a close quarters situation in foul conditions the cox needs to be able to act instinctively to control the boat so the training is indeed absolutely vital. No arguments there.
Colin
Colin
I know Colin,............. but when they were doing exactly the same job in 1940 war time Britain with just two screws and one "flappy" rudder to control the old girl in force 11 storms, you then realise just what amazing skills coxs'ns had without all this modern technology at their fingertips
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Quite agree.
As far as modelling is concerned knowing how your boat handles is worth more than all the technical gizmos, fascinating as they are.
Colin
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Quite agree.
As far as modelling is concerned knowing how your boat handles is worth more than all the technical gizmos, fascinating as they are.
Colin
you know me Colin..............I like it simple........why I like my classic lifeboats lol........this stuff is all too technical and electric wizardry for me, but each to their own choice.
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I think its great Mayhemer's share their experiences, what a great legacy for many others who enjoy the hobby :-))
Making me feel like buying one when I finish the Mersey!
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Kinmel has agreed to an experiment...
We are going to try and glean some operating data from his Shannon to better understand what is happening when is it on the boating lake.
This will involve mounting a small "data logger" on his boat that will record data to an SD card that can then be analysed/graphed after a sailing session.
Using a real time clock on the data logger and hopefully recording video we can get a better picture of what is happening (map data to video timeline).
We intend to capture:
- Date & time
- Throttle positions x 2
- Bucket positions x 2
- Trim tabs positions x 2
- ESC temperature x2
- Motor temperature x 2
- Using an onboard GPS the speed of travel over the water
- Using a sensor the pitch and roll of the hull
This might help unravel for example if there is a point where the motors are running faster than the water can get through the jets
On the other hand it might be a complete waste of time...
An interesting experiment
C-3PO
So that is what you meant by " I will send you a board over next week " :o :-)) :-))
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Gosh! Wasn't it simpler when you just had a prop and a rudder to worry about?
Makes you wonder about the benefits of modern technology.
Colin
It was simpler and achieved far less. No going sideways, no stopping in your own length in an emergency and certainly not managing 32knots !
In truth this project is because the Shannon is totally different to everything else we modellers sail and modern technology let's us manage it without the necessary months of training. Cox helm the boat literally through the seat of their pants; the boat moves and their fingers instinctively react, while we stand on the side of the lake.
We have a choice of learning all those separate control actions that make up a manoeuvre and move between them without really thinking, or we let modern technology sort out the necessary controls and we enjoy boating.
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Well I think its fascinating, Maybe one day O0
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Gosh! Wasn't it simpler when you just had a prop and a rudder to worry about?
Makes you wonder about the benefits of modern technology.
Colin
To be honest, once you get the hang of it it’s not that hard. In fact, not much different to boats with seperate engine and gearbox controls!
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To be honest, once you get the hang of it it’s not that hard. In fact, not much different to boats with seperate engine and gearbox controls!
My experience with my Pibber using 2 x Kehrer KMB jet 28 drives is that I got caught out on several occasions by putting the throttle into reverse - no clever modules in place
It was only when I got a more sophisticated tranny that I could set the range of output to stop ESC seeing a signal instructing it to reverse the motor.
McGherkin - What model/jet drives/radio setup have you used that you got the hang of and how did you control it?
C-3PO
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Oh, I was talking full scale. Same as the shannons, morse levers for throttle and morse levers for buckets, wheel for steering.
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Question for Kim - CC
The control path these guys [C-3PO & kinmel] are going is bordering on flying a twin engined helicopter O0......
eg.,
We intend to capture:
•Date & time
•Throttle positions x 2
•Bucket positions x 2
•Trim tabs positions x 2
•ESC temperature x2
•Motor temperature x 2
•Using an onboard GPS the speed of travel over the water
•Using a sensor the pitch and roll of the hull
These certainly appear all valid criteria.......did you ever experience any such conceptual ideas in control of your build?
Have also sent this via PM.......just in case you miss it here
Derek
Derek
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Talking of helicopters...
@ 30000rpm https://www.youtube.com/watch?v=wiGSIVZjqrA (https://www.youtube.com/watch?v=wiGSIVZjqrA)
I have 2 of these Graupner Jet 5's sitting on a shelf - Hmmm...
(http://modelboatmayhemimages.co.uk/images/2018/01/06/GJ5.jpg)
C-3PO
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The stern water line seems crucial- the stationary boat has to be deep enough in the water for the impeller to be fully submerged and there is not a lot of leeway between too high and too low.
This is certainly something I found with my Moonraker. The sweet spot is quite narrow and the trim tabs are significant
Perhaps Alex (IKB) could throw some light on this aspect through his work with 3D printed jet drives or TomHugill as his Moonraker doesn't hang around on the water...
This from Alex a while back
http://www.modelboatmayhem.co.uk/forum/index.php/topic,53340.msg604800.html#msg604800 (http://www.modelboatmayhem.co.uk/forum/index.php/topic,53340.msg604800.html#msg604800)
But my main question relates to the vertical positioning of the water jet output - what's best/acceptable to get the maximum thrust from the water expelled from the drive - the drive exhaust submerged under water / above water or something else?
From Alex
http://www.modelboatmayhem.co.uk/forum/index.php/topic,53340.msg604810.html#msg604810 (http://www.modelboatmayhem.co.uk/forum/index.php/topic,53340.msg604810.html#msg604810)
C-3PO - You are correct, at rest, the jet unit needs to be at least half submerged in order to reliably self prime, once underway, the whole transom tends to become exposed at high speed, so the jet is just exhausting into air, most commercial units usually have a 3-5 degree angle pointing down from the horizontal to point the stream into the water, as this will produce more thrust.
C-3PO
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Data Logger
These boards will stack on top of each other....
(http://modelboatmayhemimages.co.uk/images/2018/01/07/DataLogger001.jpg)
C-3PO
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What I need is a go on a real one.
I said " WHAT I NEED IS A GO ON A REAL ONE"
I SAID......."WHAT I NEED IS A GO ON A REAL ONE"
I SAID......."WHAT I NEED IS A GO ON A REAL ONE"
(Phew! throat hurts now)
[/size]I SAID......."WHAT I NEED IS A GO ON A REAL ONE"
Well, if you dont ask, you dont get!
Quetly then, I am hoping someone around the Mersey might hear this..............?
Adrian
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get yourself up to st annes tomorrow Adrian............training on the SLARS starts in the morning with the Shannon, which is in the dock at Fleetwood at the moment..........they are bringing the boat around tonight to upload onto the supacat and put it into the lifeboat station, vacated by the Mersey.
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the new Shannon for st annes arrives on 28th feb is to be called RNLB BARBARA ANN.
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Bit sad to see the Mersey go.
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yeh, so do I..........lovely boats...........but I don't think the Queen, whom it is named after and personally by her..........would like the old girl sat out in the cold wet fog for the next two months by a usurper taking her place in the boat house >>:-( {:-{ {:-{
The beast arrived tonight through the fog to pave the way for THE QUEEN's replacement.
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Odd my post seems to have been deleted along with the reply :/
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Making progress on the data logger.
Thought it would be neat to see if summary telemetry data could be streamed ashore as well as full dataset captured to SD card.
This would allow real time data to be monitored.
The proposed shore based screen shows:
S: current speed in cm per second ( wanted to use a unit that would make small changes very visibble)
T: trip speed - fastest speed recorded since power on
S: GPS number of satellites being received
Fy - GPS Fix - yes/no
T:15001500 - the throttle output x2 from the RX
R:15001500 - the rudder output x2 from the RX
B:15001500 - the bucket output x2 from the RX
R:15001500 - the trim tab output x2 from the RX
Temperatures for motors and ESC's Port Motor / Port ESC / Starboard ESC / Starboard Motor
(http://modelboatmayhemimages.co.uk/images/2018/01/11/WJDL01.jpg)
C-3PO
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Very nice work! :-))
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Update on Shannon Data logger
Well after lots of head scratching and migrating from Arduino to Teensy running Arduino code
Boxes arrrived today - tidy up everything from prototype spaghetti to finsihed product and fit in box, final test and ship to Alan for the interesting part!
@ the Shore - telemetry
(http://modelboatmayhemimages.co.uk/images/2018/02/08/SDL_001.jpg) (http://modelboatmayhemimages.co.uk/image/BtDVR)
@ onboard the vessel - sensor data capture to SD card / transmit telemetry to shore
(http://modelboatmayhemimages.co.uk/images/2018/02/08/SDL_002.jpg) (http://modelboatmayhemimages.co.uk/image/BtozG)
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Fantastic 8) :-)
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Silly question, but what's the resolution on the GPS module? I.e. will it measure the (relatively) small distances a model boat will travel - I presume so, otherwise you wouldn't be using it.
Just interested to see if it's worth putting into something I'm playing with.
Lance
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Hi Lance,
I am not sure of the resolution. You can research accuracy here https://www.gps.gov/systems/gps/performance/accuracy/
The GPS unit I am using is this - https://www.adafruit.com/product/746 (https://www.adafruit.com/product/746)
The GPS outputs standard National Marine Electronics Association (NEMA) sentences - simply give it power, a view of the sky and the serial data starts to pour out of the device
You can get info about NEMA here - http://www.gpsinformation.org/dale/nmea.htm (http://www.gpsinformation.org/dale/nmea.htm)
The video below is by a guy called Jeremy Blum - one clever guy!! - it might give you an idea of the resolution when he maps the data
https://www.youtube.com/watch?v=TtZEZYQG0xk (https://www.youtube.com/watch?v=TtZEZYQG0xk) @43 mins - this is quite an old video and I would guess there will be a different way to do this by now
By recording GPS sentence output you can easily map the path taken on Google Earth or GPS Visualiser etc
(https://cdn.instructables.com/F73/Q1TD/H4VQ69IE/F73Q1TDH4VQ69IE.LARGE.jpg)
C-3PO
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You have certainly worked hard on this Jonathan, thank you.
So what data trials do you all want to see?
We have the supplied Propdrive 35-42 1250Kv 800w T14 motors and also Turnigy SK3 35-42 1250Kv 755w T10 Motors
S3 and S4 Lipos
Trim tabs - fully variable, or 3 set positions
We will post the draw data on here and you can work it out yourself, or be like me and wait for Jonathan
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Playing devils advocate here We know the motors that have been supplied are the correct ones for hte jet drives BUT what is the MAX rpm of the jet drive unit as suerly if you go over the max reccomended rpm of this all you will encounter is pure cavitation inside the unit.....just athought....Reason for asking is that I have a Graupener jet drive and it is reccomended that no motor above 700watts is used
Dave
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This is an attempt to unravel what might be going on.
It's possible that we may get data that shows that you advance the throttle from X to Y and you get no increased speed but likely hotter ESC's and motors - this maybe due to cavitation as you mention.
This may prove to be a fascinating experiment that yields great results and understanding or a complete waste of time and energy (and my brain cells)
Dave (The Old Fart) retro fitted trim tabs to his Tamar and reported a noticeable improvement in performance.
I will shortly pass the mantle to Kinmel who will collect the raw data so we can all see if this approach yields any positive results
C-3PO
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Both the listed motors are 1250kv, the max RPM is the same for a given voltage.
Motor wattage doesn't tell you anything about RPM, and a 600w motor isn't necessarily going to draw 600w in normal usage. If it's only lightly loaded it'll draw much less in the way of watts, but if the impeller is fouled, obviously a big wattage motor is going to cause more havoc than a low wattage one.
I'm not sure the GPS is going to have a tight enough resolution - to get an accuracy of <5cm on a ££££££ sidescan sonar setup we were trialling in work a while back, we were using 2 fairly large GPS heads with a metre seperation, as seen here;
(https://static.wixstatic.com/media/417e9a_2efa0f7b14534fccbe1a374ee363a06a.jpg/v1/fill/w_602,h_360,al_c,q_80/417e9a_2efa0f7b14534fccbe1a374ee363a06a.webp)
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Playing devils advocate here We know the motors that have been supplied are the correct ones for hte jet drives BUT what is the MAX rpm of the jet drive unit as suerly if you go over the max reccomended rpm of this all you will encounter is pure cavitation inside the unit.....just athought....Reason for asking is that I have a Graupener jet drive and it is reccomended that no motor above 700watts is used
Dave
I've got 28mm graupner jets and had the 40mm ones in my challenger. They both had 1600kv 2400w 3674 brushless motors. cavitaion is a matter of rpm not motor power, so matching motor kv is the thing here. On mine I was aiming for 20-25k rpm, on 4s that's 1680kv ISH
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If anything on 4s Lipo, I am seeing back pressure rather than cavitation. I am using 30amp fuses and they have never blown, so Mr Ohm reckons that the motor is running at less than 440watts.
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I'm not sure the GPS is going to have a tight enough resolution - to get an accuracy of <5cm on a ££££££ sidescan sonar setup we were trialling in work a while back, we were using 2 fairly large GPS heads with a metre seperation, as seen here;
(https://static.wixstatic.com/media/417e9a_2efa0f7b14534fccbe1a374ee363a06a.jpg/v1/fill/w_602,h_360,al_c,q_80/417e9a_2efa0f7b14534fccbe1a374ee363a06a.webp)
Hi McGherkin,
Bit confused by this one and would like to understand as you may have spotted something I have over looked! - can you enlighten me or was your comment in relation to Furball's post?
C-3PO
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Sorry, I'm going mad. Don't mind me!
I thought you were going to try and set up some sort of dynamic positioning system to keep the boat on one spot, which wouldn't work very well since the boat could be a metre in any direction before it knew it was out of position.
But for speed logging it should be fine. :-))
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Shannon Data Logger update
Data file recorded on micro SD card updated approximately once per second - it actually looks like it's working!! ( Now I've posted it I can see there is a mistake!)
(http://modelboatmayhemimages.co.uk/images/2018/02/10/SDL_003.jpg) (http://modelboatmayhemimages.co.uk/image/B16y5)
Also been carrying out some range tests on the transmitter - signal still received by shore based telemetry unit even through 3 -4 feet of stone wall
Format is:
PacketID
Date
Time
Knots
Compass heading
Roll
Pitch
Temp 1,2,3,4
Radio Control RX Channel 1,2,3,4,5,6,7,8
C-3PO
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Aah yes its all very clear to me :-)) {-) Carry on :}
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Shannon Data Logger Update
This is the information that will be available on shore via telemetry. The third screen down on the left will allow the speed (and max speed for session), position of the transmitter controls for throttle and trim tabs, temperature of both ESC and motors to be viewed at the same time. A button on the shore based unit allows you to scroll through the available data screens.
The data is written to a micro SD card onboard the boat
(http://modelboatmayhemimages.co.uk/images/2018/02/12/SDL_005184ff5dd88799646.jpg)
C-3PO
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Brilliant stuff this. I am really looking forward to helping out here.
I bought two heli gyros (fast ones) to put in the line between the tranny and the trim-tab servos but I wonder if there would be any point really.
What do you think?
Adrian
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Hi Adrian,
I think the jury is out as to whether this is going to yield results, I’m hopeful and it’s fun trying…
From a personal perspective I have learnt more about quite a few things to do with Arduino so even if its a total flop for me it’s been a worthwhile journey.
The interesting bit will be once this is installed on Kinmel’s Shannon and he can give it a spin.
With regards to Gyro’s I guess it may be a case of “suck it and see” – on a very similar concept using a sensor attached to an Arduino you can determine the way the boat reacts to the sensor data and by editing the program on the Arduino adjust those reactions so you can be in control of the adventure.
If you have any thoughts/observations or wisdom to share with regards to this topic then please let us know as you have been working with the subject for a long period of time and must have amassed a significant understanding of the beast.
It’s certainly an interesting topic and will be fascinating to see what the end point is in due course - let's hope it's not a black sack:)
C-3PO