AirBoat build

[Chop]

Okay, before I toast another $60 ESC what should I do?

What I’m getting so far is to drop things down to a 2S lipo. I do have a Feigao 8XL motor (2073 RPM/Volt) that I could replace the 8L with too.

I don’t have anymore snow around here to play on, so the water should make the starts a bit easier (not as much friction).

Thanks for all the help!

[Chop]

HELP Please!!!???

Okay, before I toast another $60 ESC what should I do?

What I’m getting so far is to drop things down to a 2S lipo. I do have a Feigao 8XL motor (2073 RPM/Volt) that I could replace the 8L with too.

I don’t have anymore snow around here to play on, so the water should make the starts a bit easier (not as much friction).

Thanks for all the help!

Com'on guys, I know that there are electric guru's out there that have forgotten more than I know. A little help here would be nice.

I know that an air boat is a different kind of build:
1) an entire hull on the water and
2) a prop pushing air
but there HAS to be more people out there that can share some insight and get me close to a setup so I don't keep burning things up.

I have a Mystery 200A esc that I can use if it will work.

Once again, thanks for any help you can provide.

[j.m.]

The XL should be fine. As was explained earlier, 3000+Kv is not for 4s LiPo use. That will give you just under 30000 rpm, but the XL will have more torque and wont have to work as hard to get the same performance.

[Chop]

The XL should be fine. As was explained earlier, 3000+Kv is not for 4s LiPo use. That will give you just under 30000 rpm, but the XL will have more torque and wont have to work as hard to get the same performance.

Thank j.m.

Use the XL and what batteries?
Use the 200A Mystery or the 100A one with reverse?

[j.m.]

8xl on 4s sounds reasonable.

if you have a data logger, I'd use that with the 200 before going to the 100 just to make sure. Though you shouldn't have any problems.

You'll also have much quicker starts.

Jon

[Chop]

Thank you j.m. I appreciate the advise.

[Chop]

ESC Issues...

I have not done too much on this project since summer began. The boat ran well on water but I’m still having issues.

The 200A Mystery did not hold up in testing.
How well do you think this ESC would work: it’s a Traxxas XL-10 ESC Fwd/Rev ?
Some XL-10 Specifications:
Sport Mode Fwd / Brake / Rev
Input voltage: 4-7 Cells (4.8 to 8.4 Volts DC)
Motor Limit: 10-turns* (540 Size)
Peak Current - Forward: 150A
Peak Current - Reverse: 150A
Continuous Current: 30A
BEC Voltage: 6.0 VDC

I did purchase the Hobby King 150A High performance Brushless Car ESC (and programming card) but can’t get it to program.

I am still running it with the 8xl on 4s.

Let me know your recommendations. Remember, I want it to have reverse (for maneuvering and braking) and it can’t have water cooling because I run it on ice and snow in the winter. I suppose that if the ESC is oversized enough I might not need to water cool it. I also want it to have a BEC due to space limitations.

Here is a picture of it as a nearly finished product.

[Fluid]

Car controllers seldom work outside of cars. That Traxxas ESC is only good for 2S, you will burn it up immediately on 4S. Not cheap, but a Castle Hydra 240 would probably work if not run at max amps. The Castle ICE controllers are great and cheaper too, but I do not believe that they have reverse.

I read about your airboat on another board and that you were having major overheating issues very quickly in rather cold weather. A Feigao 540/8XL does not sound like enough rpm on 4S for that fan....something is just not right here.

A few questions:

Where is your ESC mounted?
How long are the leads from the ESC to the battery?
How long are the leads from the ESC to the motor?
What are all the specs for the fan you are using?


.

[treystoys]

Change to a standard propeller set up and you'll be much happier...the thrust cone from that fan unit is not designed for a high drag set up.

Trey

[Fluid]

He originally planned to use an air prop, but he changed the design to incorporate the ducted fan. Personally I like what he did with the fan. Sure it doesn't have the raw thrust of an air prop - but if you saw the video you'd know that it's plenty fast on the snow. (He'd increase his thrust a bunch if he used an inlet ring.)

But the problem is not that he uses a fan - it's the high heat he gets after a very short run on snow. Something is wrong with the setup - wrong motor, wrong pack, wrong fan blades......




,

[Chop]

Fluid,

I will get answers for you in the morning.

Thanks for the help.

[Chop]

Change to a standard propeller set up and you'll be much happier...the thrust cone from that fan unit is not designed for a high drag set up.

Trey

One of the advantages of using the ducted fan is that it loweres the center of gravity. The few times that I have run on water it has been very stable and almost impossible to flip over.

[treystoys]

Gotcha...I just know from my rc plane days that the initial thrust from a fan is not near as strong as a larger blade, hence the prop suggestion.

Hey Jay, yeah I saw the vids of it in the snow...when I saw this, the first thing that came to my mind was years ago after buiding a 50"+ span electric plane, I took the wing off it and had it outside going through some of the initial set ups on my then new digital plane radio, and had inadvertantly reversed my throttle then switched everything on and the plane took off like a rocket across my neighbors lawn...lol...kinda put into perspective the power that these things were capable of when you start swing a large prop at a respectable rpm.

Any vids of it on water? I'd like to see it run wet.

Good luck

Trey

[Chop]

A few answers:

Where is your ESC mounted?
In the compartment – sealed (no outside air flow). I could build a canopy with vents for winter running, not sure about summer though.

How long are the leads from the ESC to the battery?
10” (25.4 cm.) total

How long are the leads from the ESC to the motor?
15” (38.1 cm.) The extensions (braided wires) are 10” long, 12 ga. I have some 10 ga. wire that I could use instead.

I can cut about 2.5 – 3” (6.3 – 7.6 cm.) of wire out of both the motor and battery leads on the ESC.

What are all the specs for the fan you are using?
EDF Ducted Fan Unit 7 Blade 3.5inch
Blade Diameter: 3.5inch / 89mm
Outer Case Diameter: 96mm
EDF Length: 86mm
Blade Type: 7
Shaft Size: 5mm
Made from high strength reinforced plastic.
Recommended Motor: 36-70 5 Turn (14.8~22.2v)
ESC: 50A
Rpm: 2,000kv
Power: 1,000~2,500g Thrust

The motor is an 8XL with a heat sink added.

I am using a variety of batteries ranging from a 2300mah 4s 25c to a 5000mah 4s 40c

Trey, even though it uses a ducted fan the boat has plenty of thrust to get moving fast – both on the snow and in the water. I don’t have a vid in the water yet but plan to get one after I figure out this overheating issue (I don't want to leave it stranded on the water - !).

[Fluid]

There are several reasons for high heat in your system. First, the leads are 'way too long going to the motor. The long motor leads are making it tough for the ESC to keep phase with the rotor position. I contacted Castle about this once for an airboat build - they told me to make the motor wires as short as practical. You have way more wire than you need in that tiny sealed compartment. I see the potential to remove 12" or more of wire length in your application. Do it.

Another issue is the ESC, the recommended 50 amps is 'way too low for an 8XL - minimum150 amps here and 200+ is better. The Mystery may be rated for 200 amps but I'm not surprised it grenaded on you. You were stressing it heavily.

Get a better ESC, ditch the motor wire extensions from the ESC, move the latter as close as possible to the motor, shorten all wires a lot, and use a vented hatch in the winter. In the summer on water the motor will draw even more amps than on snow, so you'll have to come up with a cooling workaround of some kind.


.