YPC

Hi Curls.....

As with actual surf boards - paddling a 'Long Board' is easier than paddling a 'Short Board' - if the payload is kept consistant - however - with regards to a bigger ******** - the actual weight is increased by its mere size and the added lead to provide the righting action,( remember - the greater the boards volume the more weight you need to right it) then the size of the power-plant needs to be increased to drive it, increasing the weight further....making the bigger ******** less efficient than a smaller ********.

Bro ********. ...
Share the STOKE !

surfcurls

Thanks YPC,

That clears a bit of the Calc Questions.

Low KV ?

Why Should we Look to a lower KV for the Mav Board.
For My 2Kg Boards We run a 3000 Kv

What does a lower KV at 750 achieve for a bigger board ?

YPC

Hi Curls.....

The lower kv motor will greatly 'increase' the actual power/torque output ... allowing you to be able to have easier options..
Running a 750 kv motor on a 6s set up will still give you good speed.....and.....if you needed more speed, the 750 kv motor would easily be able to be steeped up to run a bigger pitch prop or a greater cell capacity battery, if need be.

Here's the thing !

The one 'real unknown' is exactly how heavy the board is going to need to be, especially on the day - so you want to have power options.....more than speed.
My gut tells me, to manage the intended size of wave - wind conditions and overall surface of such a wave.....you will need some serious weight.....30 kg's plus.... that's heavy.

The board could easily realise speeds down the face of 40mph plus.......remember - aerodynamics only really becomes effective over 25 mph - so for the most of it, we dont experience to much of it adversely with our smaller boards.....and yet, wind lift is an an issue for us to overcome.How much more so will it be an issue for that size of board, at the speed - also having to overcome the surface conditions.

If you go for a higher kv motor- you may have the desired speed - BUT - if you have to ADD WEIGHT - the motor and battery combo may not be able handle the overall load.

Whereas - with a low kv motor...it will better handle greater weight/load - AND -if you need more speed....you can simply increase the pitch or increase the cell capacity........
Changing a prop or battery pack in a Zodiac is much easier than changing the motor.....You are not going to have any options of 'trying it out' prior to the actual day....

The Right Options....is what you will need....for it to be a success

Bro ********. ...
Share the STOKE !

YPC

Curls....

If you work out 'just' what the righting weight would have to be for a board 1.5 m ( 5 ft) X 0.5m (20") X 0.05m (2"s) - for it to be able to sink on its rail, down to its 'rotational axis line. ( water surface - center line - rotational axis)

Righting Buoyancy to be overcome = (Volume / 2) X (shape percentage) X salt water density

= (1.5 x 0.5 x 0.05) /2 x 80% x 1030 kg/m cubed

= 16 kg's ( roughly 35 lbs)

Its interesting to see how the required weight to 'sink' the board, as it increases in size - grows exponentially, relative to the boards volume.
ie some my have thought because a 2 ft board only needing 2 kg's - if you tripled the length to 6ft - it would only need 6kg's - but - we need to remember that the width and thickness increase - increasing the whole of the volume volumetrically....

You can play around with the numbers - you will find shortening the board has far less impact on the required weight compared to the actual 'thickness' of the board....so keeping it as thin as possible will be ideal.

Bro ********. ...
Share the STOKE !

PS ....You may be' Professor Curls'....once you get this one done.......LOL

It might be an idea to simply pick up a Kids Board - 4-5ft in size - I reckon you could work with it for starters....

bearcave

Hi all rc enthusiasts......

YPC you are so right regardeing keeping ones head still with a helmet cam of any kind....... and all the other stuff you have been sayin lately well i'm just markin down the page numbers in a folder for future perusal atm.... lol

Anyway after finally getting a day in the cave just to playwith myself I put all my collected crap together to make my first helmet cam...
My thoughts were to get a video camera with properzoom hands free....thought i would base it off a cricket helmet.

Even though I can't see the screen properly i'm thinkin it will help keeping the subject in centre vision.... the counter weight is a 300gstainless metalround thing i knew would come in handy one day (also doubles as acarry handle. lol).... the arm for the camera was boing boing boinging a lot too soa strap was added to stopthat.... BUT with the lens being so far from my head it may be a challenge to keep my head still enough to keep the subject in view.

Anyway it is certainly not perfect and the cameraatm is heavy and not waterproof... Helmet and counterweight approx 1000g's... camera atm 350g's... then again my m/cycle helmet weighs 1300g's... cutting off my head for the pics has been the hardest thing so far lol.

Hey YPC... not that i have any heat generateing loose connections atm i may need to expand my bullet connection now as my girfriend is visiting the cavethis weekend.... might try out mynew creationon her first..... then again my computer reckons i did something wrong with the uploading software so it could be a while before any girlfriend oops meant surfinvids areposted soon..... LOL

RC HAWAIIAN STYLE

bearcave


thats the coolest helmet cam i have ever seen ,, love the counter weight in the back and it fits a full size camera ,, i was getting bored with all that teck talk,,,great job bearcave,, cant wait to see the footage ,,




maui john

YPC

Howzit Bearcave.....that set up is really looking great.....I am sure, like you say, with the cam in your line of sight, you will certainly maintain better picture frame - well done...looking forward to 'all' your footage......LOL

MJ...LOL....whats up ?......why are you reading 'all the boring 'Tech Stuff'......I thought you Maui boys 'go to the beach ?....anyways....I'm flattered you read it....
Why not break the bordam and share some of that 'classic Maui Stuff'....

Curls.... to share....more 'Tech Stuff'.. We ( My Son Nicholas and I) had a great session this afternoon in the 'strongest Off Shore' wind I have ever rcSurfed to date......
What came of it, was quite interesting...and even though in hindsight it sounds very obvious......it was great to actually 'see' the distinct difference.

Nics narrower board (160 mm), weighing only 1750 grams, as apposed to my, wider board ( 200 mm), weighing just over 2000 grams, was definitely 'less susceptible' to the strong off shore wind on the wave face. It was clearly demonstrated (obviously) that the wider boards surface area is definitely a 'disadvantage' when contending with strong wind...even when charging down the line, the wider board, though heavier, tends to be continually pushed up the face of the wave, due to the wind getting under more of the bigger hulls surface area...better able to lift and push the board up the wave face.

My current board has a 3.5:1 - length to width ratio - Nics board has a 4.4:1 length to width ratio - my size recommendation in the righting weight example 1500 mm X 500 mm would be 3:1....which would be way to wide......it will fly like a kite.....at Mavericks.

SO !..... I reckon .....the MVD ( Maverick Dream)......needs to be kept on the 'narrow side in proportion', which will mean that we wont want ' the Surfer Dude' standing to tall......I might try more of a crouch position, something like the Kyhoso Dude.....

A 4.5:1 length to width ratio, shaped into a traditional ' Classic Gun' purely to draw itself into an awesome deep bottom turn, to come back onto the face and head straight down the line.........long enough to reach over the troughs - narrow enough to eliminate as much surface area as possible, reducing the effects of the aerodynamic lift under the board as well as the understood bumpy surface ...........

That said...for every day, 2 - 6ft face rcSurfing with reasonable offshore conditions, I will still chose a slightly wider board over a narrow board....the added stability certainly improves the overall performance and ability.....in all.

Bro ********. ...
Share the STOKE !

surfcurls

YPC

Thanks for all the input, it will help with the MDB (Mav Dream Board )

I too thought of a gun design, as it's really the go to shape for most all of the big wave riders.
Heck whats going on around here, We agree Again ? Lol

MJ is board on the Tek Talk because he most likely has a Killer Gun Just about ready to Hit Jaws in Style .
He's always steps ahead ...

YPC

Hey Curls.....with the narrow Gun shape, the vertical balance is going to have to be 'spot on'.......we dont want the Dude pulling a 'face slap' in the bottom turn. Although, if the board is reasonably heavy, 20 kg's (40lbs plus) and the Surfer is light as in around 500 g's ( 1lb) it should be 'good'
Try and decide or find out what length of board it will be, as I would love to start working on the Bigger Bro'

Bro ********. ...
Share the STOKE !

I still enjoy the Tortoise and the Rabbit story .......it has a great ending.

InDaTube

Just a thought......

Because we don't have a 160 lb surfer weighting/unweighting etc to hold and track the board in a carving turn.....

Might we think about placing chines along rear third of the boards rails. Design them to hold on one side and release on the other in a right or left turn?

RC Surfers, in my view are a boat mimicing a surfer on a wave. (I hate what I just wrote!) What I really mean is that there are fixed boat hull design features
specifically designed to address some of our issues. Chop, bumps, lift, directional stability etc.

Also, the scale of the water surface conditions i.e. chops/bumps/wind compares to an Off Shore Racing Boat going 100 mph in 3 ft seas.

Just Say'in

kitekook

There seems to be some confusion about two of my favorite Surfers




and the board I have in my quiver:

YPC

Hey .....Indatube....I like your thinking and agree 'totally' with your definition of a ********....at least their are now 'two of us'.....LOL

It would be good to get some actual close up footage or pictures of the wave surface- as you say- all these factors are 'real' and need to be overcome.

Going out for a early morning session - before the 'wind picks up'

Bro ********. ...
Share the STOKE !

InDaTube

After a great session at the San Clemente pier this morning, I charged my batteries.
Each had a runtime of 30 min. Came in on LVC. Metered out at 13.4v each before charging.
After charging: 16.80v each
Battery A: 4985
Battery B: 4967
By the way...... My Servo gears broke on the second session.
Any suggestions on a replacement servo?

InDaTubeLarry

surfcurls

YPC,

Looking at the capabilities at the moment, an 8 lb board can handle 12 - 15 foot faces.
If we just look at the next level of a 25 - 30 foot face, isn't it possible to have a board at 16 - 20 lb range or less ?

I know my real surf board is under 8 lb at 7'2", and I add another 190 lb, but I'm also the propulsion source
A 40 lb Board sounds like a ton of weight, Why do we need to be so heavy ?


Indatube,

I think the cutouts I used from The Kyosho / NQD / Shark Are Proven Chines.

bearcave

maui john.

thanks for the compliments regarding the helmet cam... measuring twice maybe three timesthen cutting once is a good thing... thinking about stuff for months then having a go at "building it yourself " is the best but hey... and hopefully the pics shown will giveeveryone some idea's to build a better one themselves too...

Being rather useless at computer stuff and getting the camera cheap was not the best idea. The disc for setup is not the right one I can't upload anything and am now in a sea of **** computerwise at the moment.... not unusualbut...lol.

YPC and InDaTube..... I have always thought an ******** is a boat..... getting one tolooklike a surferrideing wavesis the challenge.

Kitekook..... no confusion.... the yellow/red maui creation in your quiver is a beauty but who wouldn't want a bad apple...
btwthe last pics of your helmet cam got me thinkin hard about my one.... reckon you may bethinkin of makeingone similar right now... shareing is careing hey.

BTW my girl has now left the cave after a nice weekend but reckons i'm out there... prob causeit'snot all about her but hey... LOL.

RC HAWAIIAN STYLE

indatube

These are the servos i use ,very costly
http://www3.towerhobbies.com/cgi-bin...&I=LXRJS5&P=ML
this is a good pick two
http://www3.towerhobbies.com/cgi-bin...?&I=LXFKZ7&P=7

indatube at the local hobby shop they will have a good selection..



maui john

YPC

Hi Curls......

In SA a 30 foot 'face' wave......would be referred to as an 'average 15 ft wave' by any 'seasoned' surfer..( measured from the back side)..far from anything amazing .....surfed regularly at quite a few of our big paddle in home breaks, like Outerkom - The Hoek - The Reserve - Black Rock etc....not by myself I best add..........LOL

From what I have understood......Mavericks is a 30 ft wave plus......which means a 50 ft face wave plus........or have I got it wrong...?

As much as their is a lot of 'rara' about 8lb rc surfers riding 12 -15 ft face.......I dont think I can say I have seen any footage of it been ridden 'confidently and convincingly'.....love to see some if you have......a link.

IMO....I reckon....as I mentioned before- aerodynamics (WIND) really becomes a 'big issue' after 25 - 30 mph.......If you are planning to run down the face of even a 40 ft plus wave face, with a reasonable off-shore breeze charging up the face, creating one hell of a 'updraft' as the wave itself is moving forward at 30 mph plus, you are going to need some serious weight to keep that board down. You could be heading into a head wind speed of as much as 40 mph plus. One big bump on the wave face, that lifts the nose higher than say 15 degrees, will set the board in flight....flipping it over.

With that size of wave - given the exponential wind and surface conditions........weight will be your 'friend....rather than your enemy'......

When I set up a racing F1......I always opt for the heavier set up...."you have to finish a race to win it" ......a lighter boat is sure to be faster - BUT - chances are that it will be very light on the water 'skittish' and end up on its ASS somewhere in the race ,when it hits even a small wake.

As for the crescent cut outs in the Kyhoso - NQD boards - I've been waiting for what other Think.....!!
I dont believe they are chines - chines deflect water - creating lift - the crescent cut outs to me are quite ingenious. I believe they act much like a V hull would to a degree 'allowing the board to lean even more in the turns' yet maintaining a flatter more stable platform aft of the board in the straights
Its a partial stepped hull - rather than a V- hull......if you draw it out as a cross section - you can see the similarity to a shallow V bottom theory......
It should also 'allow' the board to ride flatter, rail to rail ( keeping the surfer more vertically upright) as it travels parallel to the wave face, due to wider greater symmetric shape ( the wider portion of the boards rail line) in fact being shallower in depth at the bottom, allowing the rail to fit into the waves radius better......hope that explanation made sense..

Howzit Indatube........sounds like you had a good session......We had average on -shore-ish surf conditions at Houtbay beach (Atlantic ocean side) always good fun

As for your batteries....Those are impressive run times for 5000mAh packs....as you mentioned....you are a conservative 'surfer'

The 'safe theory practice' will tell you that you should not be running below 3.6 V /cell....which would be 14.4 v's per pack after the run......even if you pushed it down to 3.3 v's per pack, that would be 13.2 v's. You are measuring 13.3 v's at rest....which means that under operating conditions, you are possibly drawing the battery under 3.3 v's per cell......which is not good for the life span.

If you had to reduce your run time down to rather 25 minutes......you would be within your recommended 80% amps used and at a safer final voltage....preserving the batteries performance and life span.

I run the HK (inexpensive) micro digital 3.6 kg all metal gear servo's....... have not broken a gearbox to date.....I do run the single fin 'occasionally' - but - another ' bi-fin' plus is that it places very little force and load onto the servo. The two fins continually balance any applied force.....reducing the servo's load drastically.
What is the actual size of your single fin.....remember that with a single, the direct THRUST of the prop is placed against the face of the fin when you are powering in a turn, which with the bigger motors and power such as yours, can be immense in itself, besides the force of the water flow over it, as it directs the turn........
You would certainly need a bigger - tougher -servo....

Have a 'great week' Chaps !...the world is in such a CHAOTIC TIZZZ at the moment - we need to pray that peace and prosperity be restored !

Bro ********. ...
Share the STOKE !

InDaTube

YPC

Thanks for the reminder on the 14.4v rule of thumb for 4S Lipo's.
Now that I think of it, my batteries used to come in at about 14.4v when I was using the 432 prop.
I'm going to switch back from the 435 I have been using lately to the 432 and document the differences in performance, runtimes and battery usage.

Maui John

Thanks for the servo information.

InDaTube Larry

Hughengland

InDaTube Larry - great blog name

Because water will get into your rc surfer one day - I have given up trying to waterproof servos - now I use Hitech waterproof servos - they will even run underwater!
http://www3.towerhobbies.com/cgi-bin...?&I=LXBJCE&P=7

Hugh

InDaTube

Thanks Hugh......

I'm going to the Hobby Store tomorrow.

InDaTubeLarry

RC HAWAIIAN STYLE

just fininished a new board,, what sucks is it looks just like all my other board







. i am stuck in the 70ds with all those pin tails,,, LOL

YPC

Hey MJ......that board looks great......very nice finish and style..I really like the colour combo......their is nothing wrong with having a 'signature style' all of your own.
I reckon most folk would be able to 'identify' a MJ board anywhere.....

Looking forward to seeing it Ripping !.........you guys have been holding back on the footage...

I'm going to try some water base colour work 'on the foam' before I decal and glass the current board I am busy with....

I had an awesome evening session today.....back at Muizenberg beach....the wave has so much more 'open face' to play with - not as fast and close out, like Fishoek.
I caught it on the high tide, so the swell was much closer in, making it possible to ride within good visual range.......not to many surfers.....It was possibly one of my Best sessions...........came home absolutely STOKED !

Bro ********. ...
Share the STOKE !

InDaTube

Maui John,

Stay in the 70's....... Surfing wasn't a Skate Park then.

Very nice. I like that you moved the ESC up a bit. Makes it easier to route the cable to the receiver.
What is the model # of theVenom motor? KV etc.
Weight?

InDaTubeLarry

kitekook

Maui...another nice ride!

Look forward to seeing it in action.


"......it looks just like all my other boards..." I guess we all get stuck in ruts!

Your rut rages in the Surf!

You made him Goofy this time...

kitekook

Been a while since I have Surfed...my smaller board(Johnny Aloha) just doesn't do it for me, and my last Sea Horse board had some issues that were unacceptable and not worth the effort to fix..so I had to build another!

A quick coat of resin on the Hatch cover this morning and we were out in the Surf!



Aahh....this is more like it!






This is Slash...newest member to the team....

Still need to finish sand him, use rubbing compound on the entire board, and then polish...

...just couldn't wait!



Turns out to be the lightest Surfer I have made to date.




playful!


only had time for a couple batteries today...tide was wrong....but we had to get out and see how he would do.



Happy to say that all the issues of the previous board are gone!


powerful!


Long run Times!
i look forward to using it in some nice Surf!



It really felt good being out again.


I'm off the next few days so I'll bring out the Maui Board and run them together...the real test!