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Thread: Differences between high end ESC's and cheap ones for Lehner motors?

  1. #151
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    Quote Originally Posted by dmitry100 View Post
    The knife blade appears to be made out of a very strong yet flexible metal... with that in mind... I think it would act as a good shock absorber on impact

    But handling-wise would handling characteristics be similar to the stock wedge? That is... If I kept it slightly longer or same length.
    Umm, how flexible Dmitry? You don’t want it vibrating back there. Sorry I can’t help on the rudder design, I have a few designs to test but haven’t found the time at this point.

  2. #152
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    The flexibility helps, but they will snap. The best rudder blades are very stiff. You do not want a wobbling rudder blade for SAW passes. Another point to add to Jay’s is it is preferable to have more chord length than depth of the rudder. Long skinny blades do not work as well as shorter wider blades. By wider blades I mean front to back distance not the trailing edge. As a general rule of thumb the rudder blade should be at minimum as deep as the prop plus a half prop diameter. So make sure the rudder extends below the lowest point of the prop(s). For the SAW cats I would recommend 40-50mm below the prop.
    Tyler Garrard
    NAMBA 639/IMPBA 20525
    T-Hydro @ 142.94mph former WR

  3. #153
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    Any of you guys know of anyone who makes or can make decent blades?

    Tyler, the blades do NEED to be complete wedges right? Even if its 2x in chord length than the stock...

    My other (destroyed) Shocker cat never had any issues with rudder bends even after like 10 100mph+ crashes, and it was short in length but wide rudder... so I suppose that is the way to go.

    I found some decent wide blades on the H&M site... hopefully its not any thicker than my stock blade.

    https://www.hydromarine.de/Ruderanla...eln::1657.html
    Last edited by dmitry100; 05-28-2018 at 09:57 PM.

  4. #154
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    Look what I found on the HPr99 hull... This happened exactly in the same place where what there looked to be some sort of “dent” (bubble?) left during hpr’s vacuuming process...

    It looks as if a piece sort of “popped” out like a jig saw puzzle piece...

    As you can see there’s a smaller but similar bubble in the first picture below...

    hopefully this doesn’t cause the rest of the hull to crack after fixing ...




  5. #155
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    At least it's not on any of the running surfaces, should be an easy fix but that is unfortunate for such a high end hull.

  6. #156
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    Default Differences between high end ESC's and cheap ones for Lehner motors?

    Yea no biggie. Looks fixable... a bit of West systems epoxy + silica then some touch up paint and it should be fine. I think.

    I just figured it out: it’s emptiness. All that was covering that area was a layer white paint... so the recent crash must of simply pressed it.

    This is air bubble next to it that I pushed in...
    But ya, it is disappointing. I’m gonna assume it’s been known to happen.



  7. #157
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    Guys I need your help... I am a land U4RC racer which esc's and motors figured with gearing are a snap but, these boat systems are a little confusing.

    Currently I have a ProMarine 34" MTR single motor with a Seaking 120a V3 ESC and 3674 2075kv brushless motor.

    I run both 4s and 6s and mostly just tear up the lakes with friends. Maybe I'll race later.

    I use both ABC 1715 prop (for 4s) and ABC 1716 prop for 6s.

    I use 2 Revolectrix 70c 3s 5800mah batts to get 6s.

    I want it fast with a decent runtime.

    Since I'm mostly bashing the boat I am not needing a high dollar system.

    Currently I'm considering a Swordfish X 220a ESC. And upgrading to a 40mm motor between 1600kv/1700kv.

    My questions;
    1) Do I need caps installed? If so which type and how many?

    2) Which motor would be best? Go 40mm or stay with 36mm? Which Kv?

    Any guidance would be great... as I am confused as to which setup and required specs I need.

    Thank you in advance

    Sent from my SM-N950U using Tapatalk

  8. #158
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    You should probably go with any of the Castle ICE/Phoenix 200 esc's converted to water... You can get them for under 200. Probably cheaper if used. If you want to get the most of it and be bulletproof. Alot of people have success with the cheaper Mamba XLX also.

    Can't go wrong with 4000-5000uf total caps of Rubycon ZL class 470uf caps or any of the high ripple versions of UnitedChemicon caps.

    For racing I would imagine you need maximum efficiency for longest battery life if you plan to race. So probably go with 36mm and around 1700-2000kv. Theres alot of other people here who have more experience with heat racing... so i'll assume they give you input.

  9. #159
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    Quote Originally Posted by dmitry100 View Post
    You should probably go with any of the Castle ICE/Phoenix 200 esc's converted to water... You can get them for under 200. Probably cheaper if used. If you want to get the most of it and be bulletproof. Alot of people have success with the cheaper Mamba XLX also.

    Can't go wrong with 4000-5000uf total caps of Rubycon ZL class 470uf caps or any of the high ripple versions of UnitedChemicon caps.

    For racing I would imagine you need maximum efficiency for longest battery life if you plan to race. So probably go with 36mm and around 1700-2000kv. Theres alot of other people here who have more experience with heat racing... so i'll assume they give you input.
    Thank you for the info. I have searched and haven't found any water-cooled Castle ICE/Phoenix esc...

    I would like to stick with turn-key off the shelf ESC's but trying to decide which one...

    So far I've looked at Swordfish X 220a but is there something better that isn't hundreds of dollars...

    ZTW or Etti?

    I have read a lot of negative posts on Seaking 180a V3's.

    Sent from my SM-N950U using Tapatalk

  10. #160
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    You can get pre-modified water cooled Castle ESCs from Gromov at ecomaster.torgg.com.
    Paul Upton-Taylor, Greased Weasel Racing.

  11. #161
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    YEa, i wouldn't trust the seaking 180 v3 too much... even I managed to blow one up without much effort.

    ZTW 200a looks good. I hear they are pretty good quality. Etti is much pricier ... seems priced along lines of Castle.

  12. #162
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    Quote Originally Posted by dmitry100 View Post
    You should probably go with any of the Castle ICE/Phoenix 200 esc's converted to water... You can get them for under 200. Probably cheaper if used. If you want to get the most of it and be bulletproof. Alot of people have success with the cheaper Mamba XLX also.

    Can't go wrong with 4000-5000uf total caps of Rubycon ZL class 470uf caps or any of the high ripple versions of UnitedChemicon caps.

    For racing I would imagine you need maximum efficiency for longest battery life if you plan to race. So probably go with 36mm and around 1700-2000kv. Theres alot of other people here who have more experience with heat racing... so i'll assume they give you input.
    Can you give a screen shot of the right product? I mean I look for high ripple or low ESR and I really don't know what I'm looking at depending on which seller is listing specs.
    Nortavlag Bulc

  13. #163
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    Dmitry,

    That's just a bubble on the inside where the cloth did not stay "stuck" to the gelcoat. It's real easy to get those when working the resin into the cloth. One has to be very careful when brushing/dabbing the resin into the cloth on one end of the boat, so that you don't pull the cloth on the other end of the part, and make those type bubbles. Especially with a carbon cloth like you have, as it does not drape as well as glass cloth does, and does not conform to the mold as well.

    I vacuum bag my hulls to help reduce this, and to suck out the excess resin. You would think that the vacuum would pull the cloth into full contact with the mold, and it does for the most part. But I still have to make up a "putty" of resin, milled glass, and silica, and smear a radius into all corners of the hull. Chine, strakes, transom edges, all get a good filling before the layup starts.

    Since you had those two bubbles, I'll bet that you probably have more. Take a steel rod or something hard and smooth like a butter knife handle, and go over all corners of the hull. Press hard while sliding it along the edges. If there is a bubble under the gelcoat, this usually will make it break through. Better to find it now than on the water.


    If you'll send me one of your bent rudders, and the dimensions of what you want. I can get a piece of 7075 and make you one. But it will be a full wedge, and to make it strong enough, you need it to be 3/16 to 1/4 inch wide at the rear. Just don't be in a hurry for it cause I work slow!

    I would not waste time with the knife blade, we tried one on my son's gas mono in Huntsville when going for a record. It was a little smaller than the speedmaster blade we took off, thinner and flat sided like what you have. The boat was UNCONTROLLABLE period. We took it off and put the big speedmaster back on, and on his next attempt, he set the current LSG36 Mono 1/3rd oval record. Control is mandatory, without control, speed means nothing.

  14. #164
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    Quote Originally Posted by donhuff View Post

    Control is mandatory, without control, speed means nothing.
    BMW? Lol sorry Don, just had to

  15. #165
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    Quote Originally Posted by srislash View Post
    BMW? Lol sorry Don, just had to
    BMW the automotive company?

    If i'm re-quoting someone else, I didn't mean to. that's just the way I see it.

  16. #166
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    Default Differences between high end ESC's and cheap ones for Lehner motors?

    Ok so yesterday I ran a saw pass with my HPR99... after what I thought was a successful full pass... the second I let go of throttle — the boat went airborne ... made a skip on the water and then with about 5 feet of air time it made an upside down belly flop (hatch first) on the grass.

    There was no evident damage except a small hairline crack on the hatch. But what was weird was that it looked like my strut and flex became separated and busted out the bearing in the process. It was running normal until throttle release... could it have happened afterwards? My rudder was bend to the point that it got a big dent from prop.

    Its a real pain not knowing how fast it went because my GPS seems to be getting signal blocked by the cf hatch even though i always thought HPR made them with gps in mind.

    So now I’m thinking whether to buy a small gps antenna that I can mount outside (by driving a tiny hole to pass wire thru) and attach to my gps inside. Because I know I’ll be fishing for the gps in water every time I make a pass with crash. Have any of you did anything like this?

  17. #167
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    At speed - when you back off of the throttle - the prop is now turning the flex shaft the wrong way .

    Larry
    Past NAMBA- P Mono -1 Mile Race Record holder
    Past NAMBA- P Sport -1 Mile Race Record holder
    Bump & Grind Racing Props -We Like Em Smooth & Wet

  18. #168
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    so a more gradual release of throttle is always a good idea then

  19. #169
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    Quote Originally Posted by dmitry100 View Post
    so a more gradual release of throttle is always a good idea then
    Yup

  20. #170
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    No one may be here but if you are. Look at this new 40KW controller that does 400 continuous and 600 max at 20s lipo . Look at the footprint. It has balls as it can also be used for EV. It will run high pole count NEU or Lehner motor quite well and efficiently. The processing speed of the other drives cannot remotely compare nor are they as power dense. They are $1200.00 a piece though and the before mentioned are huge in comparison. You should add some ceramics to compliment such large bulk electrolytic because they have real difficult time dealing with the faster transient esp with such long barrels to fill if you plan to go that route. High end drive$ that wont drive all the motors doesn't seem right does it? Another problem with these drives can be motors with very short coils because they have increasingly lower induction and the way to get out of this problem u have 3 options. One is lowering the bus voltage , 2 is adding load, or 3 raising the PWM. So a boater picks which on a boat with the prop he already wants? Raising the pwm of course .The MGM cannot match this drive as it has 3 times the pwm capability. MGM is also not user friendly. If you make mistake in setup and and burn it many people had to pay for repair.

    I have 2 castle 200 Ice hv v2s and they have been flawless for me but still the cant turn high poles counts beyond the limit of the processors. The reason they do better with all motors is they run a 6 step BLDC algorithm not a sinus one which takes more processor speed. It isnt just the poles that create the switching issues the type of commutation algorithm the use plays a huge part in it. Some designers got around this by using a fast acting logic array in addition freeing the processor to do more work in commutation. A sinus drive works best with a sinus motor and a bldc drive works best with a BLDC motor.Sinus setups are cleaner a by a few % more efficient at the low end but at the high end theres not much difference. Some of the most sophisticated drives right now are actually the 30 dollar BLheli 32 inverters you can buy anywhere. If you team its logic with a custom bridge you'd really have something. Low pass and notch filtering will pay you dividends. More poles make more torque so its a matter of choice not quality between the two motors. Lehner may have a slight advantage in rotor design with sliced rotors and CF sleeves but the NEU is still a very good motor with a winding factor of one. They also have released a TL4 rotor at the request of 5FD pilots that can turn more rpm. All the wire except the end turn go toward making torque.The Lehner eliminate many of it problems simply by being a 2 pole. At that its working harmonic is the fundamental 2 pole. In a NEU the working harmonic is the 4th. That changes things as far as the rotor loss is concerned.



    I'm in cooperation with Phds at ABB's corporate research center in Raleigh NC at NC State.
    Were working on the newest winds that will lower the BEMF THD on a high pole count external rotor FSCW machines.

    You can observe here that running a BLDC Inverter with Sinus motor or Sinus inverter with BLDC motor only creates more ripple.
    This is another way matching can give better performance.
    Attached Images Attached Images
    Last edited by eXoNerated; 06-20-2020 at 04:50 AM. Reason: Changed "BLDC drive" to "BLDC motor"

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