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>> Home > Boat Building Blogs > H.M.S BRAVE BORDERER
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mdlbt.com/40884
H.M.S BRAVE BORDERER Print Booklet
Author: RHBaker   Posts: 20   Photos: 40   Subscribers: 1   Views: 4152   Responses: 89   |   Most recent posts shown first   (Show oldest first)

Showing page 1 of 2   |   Jump to page: 1   2  

mdlbt.com/48608
HMS BRAVE BORDERER - Posted: 3rd Dec 2018
Back to the build. Next milestone, to complete the superstructure and engine covers. The superstructure is essentially a cowl that supports the open bridge and serves as the air intake for the gas turbines. The engine covers fit into the rear of it.
The superstructure is full of curves and will be interesting to make. Still trying to save weight, decided to make it out of glassfibre. Rather than first make a plug then a female mould and finally the cowl, wanted to try the technique of making a plug out of styrene foam sheet, then covering it in a glass fibre matt. Once the glass fibre is set, the foam is dissolved out using a solvent and the cowl remains – Inshallah!
To ensure the foam did not react to the glass fibre resin, painted the finished cowl with enamel paint before sticking the matt down. See pictures.
What a mess! The resin had crept under the paint and into the foam dissolving it. When the
resin dried the plug had shrunk slightly and had the surface finish of a quarry. First thought was to hurl it and start again, this time in wood.
On second thoughts, wondered if the plug could still be used. Decided to build it up with wood filler and from it make a female mould, as originally intended. The cowl would then be made from the mould. Built the damaged plug up and sanded it smooth. As the plug would be covered in fibreglass, the surface finish was not critical. Brushed a coat of fibreglass on the plug and, after drying filled any defects with glaze putty and sanded smooth.
Once the finish and dimensions were satisfactory, applied a thicker coat of glass fibre to the plug. This was again smoothed down, waxed with carnauba polish and then covered in mould release. From it the cowl was made.
Picture shows plug, mould and cowl placed side by each. The cowl requires reinforcement; the fittings and various mountings then adding before installing. A trial installation showed that it fitted properly the deck and was accurate.
A lesson for the next time is to make the plug and mould much deeper than the finished item. That will allow any rough edges, on either the mould or the component, to be trimmed off leaving a smooth fibreglass edge.

Attached Photos - Click To View Large

Response by kevinsharpe on the 4th Dec 2018
Hi
Did you consider building the superstructure using plastic sheet as plastic would bend around the curves.

Regards
Kevin
Response by RHBaker on the 4th Dec 2018
Hi Kevin,
Yes I did, because of the complexity of the shape that was another technique that could have been used. I decided to use glass fibre as the cowl is around 7" wide and 3 1/2" deep. Considered a draw of that depth was beyond my skill and facilities with plastic sheet. If they are available it would have been a good approach.
The more I work with glass fibre the more forgiving it seems to be. Not many mistakes that cannot be disguised or corrected!
Rowen
Response by RNinMunich on the 4th Dec 2018
How true, how true Rowen👍😁

mdlbt.com/48149
HMS BRAVE BORDERER - Posted: 20th Nov 2018
Finally the new brass propellers arrived, delayed about a month in one of Canada's regular postal disruptions. After minor modifications to the boss profile (the brass are more streamlined and thus longer than nylon) to give clearance with the rudder leading edges, they were easily installed.
Could now refit the electrical equipment previously removed to get access to the shaft couplings.
Inevitably took the opportunity to make “improvements”, so then could not get anything to work! After much frustration determined the problem was not from my improvements, but from the cheap and nasty slide switches provided with ESCs. These must have got damp during the test runs and corroded internally. Suggest when using these switches they be consigned to the garbage and replaced with proper toggle ones.
Had decided to use the centre brushed motor/propeller for manoeuvring and low speed operation and then the outer brushless for high speed. Brushless ESCs do not modulate smoothly and motor operation is erratic. This was particularly evident when going from forward to reverse and vice versa. Using a lever control Tx, it was also easy to inadvertently operate the brushless control along with the brushed making the model response unpredictable.
After some thinking, decided to insert a small relay into each of the white signal wires for the brushless motor ESCs. These relays would be controlled by a RC switch operated by another channel on the Rx. Hoping this way the brushless motors could be switched on and off whenever desired. The two relays would retain the ESCs as separate circuits and avoid any interference between them.
The idea worked, can now operate the brushed motor confidently knowing the brushless will not be inadvertently triggered. This means low speed manoeuvers can be gently undertaken using the modulation and control ability of the brushless motors and, by selecting the auxiliary control, can add the high speed capability of the brushless.
Am also hoping that when the Li-Pos trigger the low voltage cut-outs in the ESCs, this will retain a “get-home” facility on the brushed motor as that ESC operates independently.
Much to look forward to when next on the water.
Response by RNinMunich on the 22nd Nov 2018
Mornin' JB,
Guess I'll have to remain 'agnostic' on this issue for now - I'm still to be convinced. This might explain a phenomenon I've noticed during testing of the Taycol Supermarine I've just renovated for Colin. More on that later in the 'Supermarine resurrection' blog.
I'll do some experiments using my digital scope and see if I can trap and measure these elusive spikes for various wire lengths😉
Can't comment on the guy from Castle, don't know them, except to say that I found his comments a bit vague and without explanation.
There are also contradictory posts on that link; some say before the ESC some after. Can't really see the point of putting the caps in front of the ESC, switching spikes SHOULD only appear on the output side I'll look at that on the scope, and after all a fuse to protect against fouled prop and jammed motor is standard fit between battery and ESC, or should be! So some wiring extension for that is essential. Also I would expect the battery to flatten any spikes that do appear at the ESC supply side.

As you say the internals of several 'manufacturers' ESCs are often the same. Nothing new, branding and badge engineering has been going on for decades for all sorts of things and no RC kit manufacturer / distributor produces his own components. Important factors are; quality of his own assembly and where does he buy his components - originals or cheap copies?

28 ESCs! Wow 😲 and I thought I had a lot!
As reported I have so far had good results with the Quicrun series, both brushed and brushless. Next one to test is their Dual Brushed version.
Prior to going brushless I used a lot of Graupner ESCs - made in Korea., never managed to blow one of them either, not even the little micro and pico jobs.

Thanks for raising this issue - I like a good debate and we can all learn something from it I hope👍 Plus; piquing my curiosity is always dangerous 😁
Greetings to Down Under from 'Up Over', cheers, 😎Doug
PS Further thought just struck me (Ouch😡); if this is really a dramatic problem why have I never seen any warnings about it in any ESC instructions? Yes, I'm THAT guy who actually reads the instructions!!
Response by RHBaker on the 22nd Nov 2018
Thanks all for your help and suggestions. Plenty to noodle over during our cold winter nights.
Rowen
Response by RNinMunich on the 22nd Nov 2018
Spaghetti or Farfalle? 😁😁 bon appétit 👍

mdlbt.com/47253
HMS BRAVE BORDERER - Posted: 19th Oct 2018
The weather has quickly turned colder, giving an excuse to get back to this model.
Stripped out much of the interior and the prop. shafts to replace the nylon propellers with brass. These items all needed removing for painting, so decided to paint the hull before reassembly and then moving onto the superstructure.
Fortunately, examining similar naval vessels and several U Tube videos, confirmed the hull as light grey, the deck a darker one of the 50 shades of grey and the lower hull below the waterline black. Used thin Tamiya masking tape to define clean colour separations, followed by regular tape, masked the hull into colour sections and sprayed using “rattle” cans. After the colours applied a light overall Matt coat to subdue any shine. The results are satisfactory. Will now reassemble and move onto building the superstructure and the other fittings.

Prior to the season closing decided to experiment with my new Flysky Tx/Rx package, shortly to be fitted to this model. This Tx has a servo limiting function, which was hoping could also be used to restrict ESC output. Would like to make the full speed motor response correspond to full Tx control position. Currently can over power the model; which lifts the stern, causing it to come off the plane and then dig the bow in.
Was thinking that if full throttle could be set at around 90% forward control movement and 40% sternwards the model would retain adequate performance, but without being overpowered or very sensitive to control lever movement.
As the Brave was not available, tried the idea on my Daman Stan 4207 model. This is brushed motor powered and a good performer. Obviously the settings for the Brave will be different, but at least could try to see if the idea would work – it did!
This Tx function is easy to use and adjustments can be made whilst the model is on the water. Once the ideal settings are achieved they can be programmed and then retained in the Tx. Will try this on the Brave when back on the water next Spring.

Attached Photos - Click To View Large


mdlbt.com/46526
BRAVE BORDERER - BRUSHLESS SUMMARY - Posted: 25th Sep 2018
Although have modeling experience, all my earlier vessels used brushed motors. This was my first brushless. The model is now running well, but thought, for the benefit of others considering this transition to summarize my experiences.
Must stress the performance of a brushless motor is incredible when compared to a similar sized brushed; for a vessel such as this they are almost obligatory. They are worth the trouble!
Had been advised that the best powertrain installation for a 37” Brave Borderer is either a single or twin screws, not three. This was good advice! Much heartache could have been avoided with a single screw installation. Unfortunately, that is not the correct layout for a scale builder.
Tried three major powertrain iterations, with several variations within each group. All motors are 28mm O/D :
1) The original installation used 3 x 4600kV inrunner motors with 30 A ESCs. Had bought these items used. The motors were too fast and had little torque. The ESCs also did not have adequate capacity. The result was erratic performance, a high fuse failure rate and the eventual failure of an ESC and motor
Picture #1.
2) First upgrade was to 2 x 2400kV inrunner motors, using 50A capacity ESCs. The centre shaft was fitted with a brushed motor. This combination did work, although suffered greatly from motor “squeal” and “stutter”. Eventually a motor burnt out and failed. Picture #2
3) Upgrade two: retained the 50 A ESCs, with 2 x 2600 kV outrunner motors, again with the brushed inner shaft motor. Reprogrammed the ESCs to soft start parameters. Much better, performance and reliability can now be considered acceptable. The squeal and stutter are largely corrected It has justified the challenges of getting here. Picture #3
Have tried both 2 and 3S Li-Po batteries, suggest use the minimum voltage needed to achieve the desired performance. Higher voltages translate into faster response and performance, but with less control modulation. The model can be easily overpowered.
In summary, from my experience. For a marine application; chose low (under 2000kV) kV rating motors with an outrunner layout wherever possible (produce more torque than inrunners). Use ESCs with a ratings comfortably in excess of the motor ratings, fit fuses to supplement any ESC protections. Ensure the ESCs are programmed to “soft start” characteristics. Also, the obvious check of making sure shaft alignment is correct is even more important with the higher speed capability of brushless motors. In spite of the trails, cost and tribulations of getting here. Have enjoyed the challenge and the end result does justify the means.
Also, do not finally fit the deck until you are satisfied with the performance. Making the changes described with limited access would have been very difficult and frustrating.

Attached Photos - Click To View Large

Response by Donnieboy on the 6th Nov 2018
Great idea using separate feeds.One less worry.👍
Response by RHBaker on the 6th Nov 2018
Never thought of using separate feeds, good idea. That pump looks like the one I used too.
Response by jbkiwi on the 7th Nov 2018
The only thing you might have to watch out for is back feed from the pump out the aux tube (when moving) if you don't set up the y joints (must be y not T ) to create a venturi effect from the pump side. Doesn't matter standing still but at speed a T junction might reduce the flow as the flows will be fighting each other slightly. The beauty of the twin system is that if you are running a lot at high speed you could turn the pump off to save power. The best place to position water intakes is I have found is directly behind the prop (I usually just squash the brass tube slightly, fair it, cut it off at 45 deg and set it to just sit in the prop wash). At lower speeds especially, the prop will help to push water into the tubes rather than just relying on speed alone. Never had a problem with pickups interfering with rudder effectiveness as long as you fair the pickups nicely

mdlbt.com/46407
HMS BRAVE BORDERER - Posted: 21st Sep 2018
Adjusted the transom flaps and reprogrammed the ESCs to the softest start settings, retested. Until now, the test runs did not have the duration or stability to really examine what was happening.
Using 3 S batteries acceleration is rapid and a is plane quickly achieved. However, as the acceleration continues and speed increases, the bow digs in. A cloud of spray then surrounds the model as the plane is lost. Brushless motors do not modulate as smoothly as brushed and adjusting power tends to be erratic or exaggerated.
This is a scale model and the propeller shaft angles are per the plans. The thrust from the propeller has two components, horizontal and vertical. The horizontal propels the vessel forward. However, the vertical component forces the stern upwards and, correspondingly, the bow down. Have moved as much weight as possible towards the stern to counteract this, limited by maintaining the correct displacement and waterline. The easiest solution is to reduce motor power, decreasing both speed and the lifting component.
Decided to retry the 2S batteries as they give reduced power. A plane is again achieved, but as the motor response is more docile, it can be controlled. If the speed gets too high the bow lowers, as before, but the motor output can be more easily adjusted.
Spent a pleasant half hour or so with the vessel accelerating onto and off a nice, controllable plane. Much less spray and drama than with 3S and much more controllable.
Have now decided to revise plans and use 2S rather than 3 batteries. A further advantage is the motor noise is muted and now sounds more like a gas turbine than a dental drill!
Finally feeling comfortable with the model. Will thus shelve further building until the late fall when sailing in Canada concludes. Want to enjoy the rest of my fleet in the meantime!
Will summarize my experiences with brushless motors in another blog shortly for the benefits of others contemplating their use. After restarting the model will resurrect periodic build blogs to advise progress.
Response by RHBaker on the 23rd Sep 2018
Thanks Lyle, will research your entry. The wider chine strips are an idea had not considered. Will do so, although it works well now that could be a further improvement.
Rowen
Response by kevinsharpe on the 6th Nov 2018
Hi Lyle.
Note your comments on planing strikes or the hard chine hull. I have a 52" Veron FPB. Powered by two Graupner 900 motors. When she gets up on the plane loads of wash coming over the rear deck. Am I right in thinking that if I fit a strake to each side of the hull at the bottom of the vertical skin and flush with the bottom of it it will assist in planing and keep wash away from the rear deck. If I fit them I intend to flare them towards the bow.

Regards
Kevin
Response by bubbletop409 on the 9th Dec 2018
You are correct in your thinking. The component is called a spray rail and is mounted at the chine line from bow to stern. The spray rail provides additional lift so planning can be achieved at a slightly lower speed, and at the same time deflects the spray down and out from the side of the boat at speed.

mdlbt.com/46105
BRAVE BORDERER - Posted: 11th Sep 2018
Been researching the squeal and stutter on other websites and conclude RFI is probably not the major contributor. Others attribute it to a mismatch in the ESC / motor timing, which seems more likely. Whatever caused it, resulted in the affected motor failing. Which came first, the failure causing squeal or squeal causing failure is open to conjecture. Much to my surprise the manufacturer has decided to replace the motor under warranty.
In the meantime, the motors I had planned to use originally (2800kV Outrunners) came into stock, so purchased a couple. Until now have had to use the ESC default settings as did not have a programming card. This also arrived with the motors. Following advice from another contributor reprogrammed the motors with “softer” start and acceleration settings.
Fitted and tried the new motors and settings. On the bench, the
squeal and stutter have almost gone. The motors are also more tractable.
As the brushless motors are now going to be used for high speed operation only, with slow on the centre brushed, thought could simplify the controls by putting the brushless ESCs on one control system using a “Y” lead. However, this introduced inconsistent and erratic motor responses. Reverted to the two previous separate controls, port and starboard.
On the water the performance is fine, as is the reliability. The 2S battery gave almost half an hours operation. The bow lifts nicely with both 2 & 3 S Batteries; plenty of spray. Hopefully resembling a 50 knot vessel! Another adjustment is needed to the transom flaps to try to hold the bow down later as she accelerates.
Feeling now to finally be making progress with this model.
The squeal has not gone, nor has erratic motor operation. The squeal is high pitched screech, rather like treading on a budgie! When it happens, bringing the control back to neutral and advancing it again almost always overcomes it. The erratic operation happens also when starting and is rather like the motors are not getting a signal to react to the control. Again, returning through neutral briefly seems to correct it.
The revised motors and ESCs have increased the weight to 6lbs for the hull including all running gear, excluding batteries and superstructure. Whilst still trying to control weight have concluded this figure is satisfactory as the performance certainly is.
Response by RNinMunich on the 12th Sep 2018
Hi Rowen,
i just wondered how much the brass whips compared with steel, and how much it expands with friction heat if the bearings bushes are a tightish fit!?
Don't think I've come across brass shafts before 😉
Good luck👍 Doug
Response by RHBaker on the 13th Sep 2018
Doug,
Am sure it can do both of those! So far, have not had a high speed run long enough to really test the brass shafts. I hope to only need to use it for a couple of test runs shortly before will dismantle, make those upgrades and then finish the model over the winter.
Rowen
Response by jbkiwi on the 22nd Sep 2018
I've used small brass shafts in brass bushed tubes with oilers in my MTB and they've lasted for 20yrs of average use, although they get a bit noisy when short of oil. Best would be brass shafts in brass tubes with Teflon/Nylon/ bronze etc bushes (a center bush as well if poss - have used these in ic power boats for years with hard steel shafts for the power). Brass is good as it's self lubricating to a degree and with a good quality oil can run quite smoothly and quietly, and is very simple, and when looked after won't corrode like steel or miniature ball or roller bearings (unless stainless).

mdlbt.com/45556
BRAVE BORDERER - Posted: 29th Aug 2018
Decided to separate the two power systems; one to the port ESC and motor and the other the starboard. Hope this will reduce interference between the motor systems. Have also reverted to a remote battery powered Rx rather than the BECC system, again to reduce possible interference. The modifications did not resolve the problems. The squeal and stutter are still present, but much reduced. Sounds rather like a slipping coupling, but as these have been checked many times they can be eliminated. Apart from the squeal and the stutter, everything works well. The squeal /stutter occurs at start up, when it happens the control is returned to neutral, If the motor is immediately reselected, usually the problem goes away and the motor runs up cleanly. It only occurs when both motors are selected at the same time. Either runs up cleanly when selected individually.
Interestingly enough, did some research on various Model Boats site and found some references to RF interference, no specific solutions though. Also examined some Aero modeling sites as they use powerful brushless motors with ESCs. There is some history of the problem there. Evidently when the mosfets (?) of the ESCs convert DC to AC, RF interference is generated. It can often be addressed by using ferrite rings on the ESC control leads. My latest ESCs actually have ferrite rings, so the problem must have been anticipated. This might account for the latest reduction in squeal and stutter levels.
Am at a loss to think of any other modifications, so decided to conduct a water test. Maybe it is a characteristic of brushless motors, but their control response seems “ragged”, not smooth as with a brushed. Anyway, the squeal and stutter seemed reduced yet again, perhaps the water load damped them down.
Was able to start exploring both the performance envelope and the viability of the brushed centre shaft motor. First impressions are that on a 2S battery the performance is fine, but it sparkles on 3S. On 3S the stutter and squeal are more pronounced though. Intend to do further trials but, unless something unexpected occurs, now plan to use 2S power.
The centre brushed motor idea works well, this layout seems a good compromise. Will design a simple switching circuit to ensure the brushless motors can selected separately. This will avoid the inadvertent operation of both brushed and brushless unintentionally as they are on the same control stick. The brushed can then be used for low speed operation.
Returning to the problem of squeal and stutter – has anybody else experienced this and how was it resolved?
Response by BOATSHED on the 25th Sep 2018
Where do you get these motor mounts from please and how much are they ? Not seen one of these like this before.
Response by RHBaker on the 25th Sep 2018
Made it myself from some scrap aluminium plate. Fortunately have access to some machine shop equipment.
Response by BOATSHED on the 25th Sep 2018
Very nice, shame they are not on the internet for sale. Well done for such fine work. I'm shocked by some of the work I see on this site and wish I also had the expertise and tools do such fine work. I'm watching your build with eagle eyes. Please keep posting. Will you be adding video of her running at some point ?

mdlbt.com/45217
BRAVE BORDERER - Posted: 19th Aug 2018
Blog 4 update – Adjustable transom flap using metallic tape did not work. Think the vibration caused flexing and fatigue, so it finally split. Fortunately had established the correct angle, so reproduced the flap arrangement with a fixed thin alloy plate. Much more robust.
Have installed the new brushless motors and ESCs. The current layout is brushless motors on the outer propellers and brushed on the centre, all powered by a single 3S Li-Po battery and Rx.
Am hoping to commence water trails this week, but have found an issue which was also present with the original brushless motors.
When either brushless motor is powered up it operates nicely, however, as soon as the second motor is started either motor “stutters” and a pronounced “squeal” can be heard. The brushed motor is unaffected. Have now tried several ESCs but to no avail, the issue remains.
It can be cured though by powering each brushless motor with it's own battery. When this is done everything powers up cleanly and quietly.
The obvious solution is to use two Li-Po batteries and abandon the single battery approach. Am reluctant to do this as the model weight will increase yet again.
Has anybody experienced this when using twin brushless motors and, if so, how was it resolved?
Response by RNinMunich on the 19th Aug 2018
Hi Rowen,
Interesting snag! Can you send me a wiring diagram please.
Sounds like you might be getting some cross coupling of control pulse ripple through the battery wiring.
Reminds me of similar problems on naval COMMS systems where we had to fit filters to all the power supplies to prevent cross coupling of sensitive info from 'Secure' to 'Plain' systems via the power leads!

BTW: All brushless squeal and scream until the the pitch gets beyond human hearing frequency range 😉
Alternative: If you use two 3S LiPos, each of half the capacity of the original, you should get the same endurance with only a small weight penalty. This ain't curing the real problem though 😉
Cheers, Doug 😎
Response by jbkiwi on the 22nd Sep 2018
Starting a bit backwards here as have posted more recently with some ideas. If you are going to have a twin brushless system using 1 REC, you probably should have twin 2200Mah 2s lipos, a power lead (I use a JST plug set) taken from the input leads of ONE ESC (not the batt leads) (I break into them and solder the JST leads on ) run those to a UBEC and then to your REC switch then to your receiver. If your ESCs have a built in BEC, withdraw the red power wires from the BEC receiver plugs and tape them back as you now don't need the power from these. If your TX is 2 stick 4/6ch etc and is capable of being changed to 2 throttle sticks (provision for ratchet strip - copy if necessary - on opposite gimbal - ie using set up as mode 1&2 throttle) you can use the existing throttle and elevator stick to give full independent control with either rudder or aileron Ch for rudder. The Chinese ESCs I use have a power switch as well as BECs which is handy. I would keep the brushed system separate from the brushless altogether with its own battery (or try power from the other batt as described above) otherwise you may be trying to mix 3 phase and single phase at some point. If you are using 2.4 you could use another paired 3ch receiver (does work, as mentioned in my later post) to only run the brushless throttle from a rotary sw on your TX (if you have that )

mdlbt.com/44099
BRAVE BORDERER - Posted: 23rd Jul 2018
This hobby gives countless opportunities for changing ideas! After some thought, have decided to try another approach.
Whilst brushless motors give fantastic performance; so far have had poor experience of system reliability. As more information and advice from other modelers is gathered, suspect have been using undersized ESCs, accounting for many of the problems.
However, whilst still waiting for the new brushless motors an idea developed. To instal a brushed motor on the centre shaft, whilst retaining brushless on the outers.
My thinking is this could provide several advantages such as; a better slow speed performance more suitable for manoeuvring, lower current draw, improved fuse life and a reliable BECC output. It will also operate at below the Li-Po cut-off voltage, giving a “get home” facility in the event the brushless ESCs cut-offs operate. However, there is a slight weight penalty as brushed motors and ESCs are heavier than brushless.
Fitted a brushed motor of the same O/D and mounting arrangement as the previous brushless to minimize installation issues. With a reliable Mtroniks ESC from my stock and suitable fuses, fitted these items along with the ballast and battery used earlier. Now, back to the pool.
The system worked well. The vessel speed is much less than with a brushless motor on the centre shaft, but control-ability greatly improved. With the triple rudders she steers nicely.
The thought of using a brushed motor on the centre shaft, with a brushless motor on each of the outers is attractive. It is hoped the additional operation of the outers in conjunction with with the centre shaft, will provide the expected performance. The centre shaft would then also provide manoeuvring and reliability with the outers shut down.
If this works, think this power-train combination could be ideal. Once the new brushless motors and ESCs arrive will instal and report.
On the attached pictures, the first shows the ballasted model sitting with the brushed centre shaft motor, the second with a brushless. The difference in draft is imperceptible, the bow sits slightly high in both cases. The third shows the model with the brushed centre shaft operating only at “full” speed.

Attached Photos - Click To View Large


mdlbt.com/43570
BRAVE BORDERER - Posted: 8th Jul 2018
Whilst waiting for the new motors and ESCs, reviewed videos of the vessel under power and noted that as the speed increases, the bow lifts towards a plane. However, as she gathers speed the transom flaps become effective, forcing the bow down in a cloud of spray. At this point the plane has been lost and the model becomes almost uncontrollable.
Decided to temporarily ballast the hull to simulate the new motors and ESCs, then try to establish the optimum flap angle using just the centre propeller and shaft. This is the original 2838 brushless motor installation with a 30 mm propeller. With this simulated drivetrain it would also be an opportunity to determine the best battery locations for both 2 and 3S Li-Po batteries.
Made up an angle template with a spirit level to get the correct deck inclination with the vessel floating at rest. From this located each type of battery statically - somewhere close to the mid-point of the hull. Which also seemed as good a place to start as any!
Somewhere in the research for this model found a reference to the transom flap angle. This was at a 2 degree -ve (pointing downwards) angle. Installed the 2S battery and tried the model. The bow dug in at speed. Adjusted the flap to a straight and level position and tried again. The bow still wanted to dig in, but to a reduced extent. Readjusted the angle to 2 + ve and repeated. The bow now lifted so the forefoot just cleared the water and then remained in that position.
Replaced the 2S battery with the 3S. The extra power obviously increased speed and the bow lifted slightly further. The spray was deflected by the chine rails and a level plane established.
The conclusion is that the transom flap angle is critical to the correct planing of this model and that it should not be negative.
Until the new motors and ESCs are fitted will leave the transom flap and battery locations as is. Once these components are installed, intend to repeat the test. Am confident that with some fine tuning the model can be now made to plane properly at a scale speed.
Interesting to note that the model will just about plane with only one propeller operating – wonder what it will be like with all three?
Response by RHBaker on the 12th Jul 2018
Thanks. Not too difficult to rig something up like that. Just need some backordered items so can try them!
Response by RNinMunich on the 12th Jul 2018
Bon chance mon ami👍
Don't know what TX you have but you may be able to do the mixing there.
If not there are several separate mixer boards on the market.
This one for instance; Action Electronics P40D from Component Shop.
It's good for both brushed and brushless motors😊 See pdf data sheet.
Mode 1 might be good for Brave Borderer!?
http://www.action-electronics.co.uk/Mixers.html
https://www.componentshop.co.uk/p40e-marine-motor-mixer.html

Have fun, cheers, Doug 😎
Response by RHBaker on the 12th Jul 2018
Hi Doug,
Certainly having fun and gaining more appreciation for the various drivetrain combinations available to us. My objective for this summer is to get a combination, using all three shafts, that works properly at all speeds.
This coming winter will refine by using items such as you recommend. That item would help, so will keep the details on one side.
The program would be assisted enormously if a supplier (located in Hong Kong) was able to meet back-order commitments!

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