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There is a fine line between "hobby" and "mental illness." -
Wow! Really surprised there! Nice power!My prop hasn't been wet in a while.
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I like the build so far !
An air boat was the very first boat i built when i was 8 !
But it looked more like a box and i never saved enough cash back then to buy a radio and motor, but it looked good on the shelf till i threw a basketball in my room and it smashed the hull ;-)
looks great !Comment
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HDPE = High-Density Polyethylene
There are no adhesives, tapes or glues that provide a permanent, watertight bond to polyethylene.
This "boat" will probably be used 90% of the time on snow and ice. The HDPE will have less friction than wood making the boat slide easier.There is a fine line between "hobby" and "mental illness."Comment
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I am familar with HDPE as some of the pipe that we use is made of this. I have also seen some full size airboat manufacturers talk about using it on the bottom of their hulls. Thats what caught my eye when you mentioned it. Does it come in sheets or rolls? How are you going to attach it to your hull? Where do you get it from? You've really peaked my interest as I'm looking at building an airboat out of insulation foam, but wondered about using HDPE on the outside of the hull.Comment
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Hot!!!
Okay, the body work is complete (almost).
I put things back together and gave it another test run. I installed this ESC (it's 100a w/reverse). I programmed the low voltage cut off at 13.2v for a 4s1p, 3800 mah lipo.
Unfortunately the batteries I had were not fully charged. I ran it for a very short (40 seconds?) run and the low voltage cut off kicked in and I brought it back. The battery seemed pretty hot, a measurement indicated that it was about 120° F (49° C). The ESC was this temp as well. Outdoor temperature was about 20° F (-6.5° C).
This seems "a bit" hot, any suggestions?Last edited by Chop; 02-27-2010, 02:00 PM.There is a fine line between "hobby" and "mental illness."Comment
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Sorry for taking so long to answer you damfurst, I've been busy sanding & painting.
The sheet of HDPE that I have came from a local plastic supply house. They gave it to me for free. I am going to attach it with counter sunk machine and wood screws. Blocking for the screws was added for this purpose. This blocking can be seen along the sides and down the center of the hull in this picture.There is a fine line between "hobby" and "mental illness."Comment
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Well. I charged up the battery(s) and ran it again.
It ran good, but still overheats! This time, I ran it for a few seconds more that the 26 second video shows. The ESC got so hot that the solder joint on one of the connections (at the ESC) melted. I checked it and it was 180°F+ (82°C). The battery was just as hot.
Not sure what to think at this point except to get a higher amp ESC.Last edited by Chop; 02-27-2010, 11:00 PM.There is a fine line between "hobby" and "mental illness."Comment
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Hey, I really do appreciate the info. Are you doing just the bottom or some on the sides as well? I've seen pics of some full size ones that have it on the sides, at least the back 1/2.Sorry for taking so long to answer you damfurst, I've been busy sanding & painting.
The sheet of HDPE that I have came from a local plastic supply house. They gave it to me for free. I am going to attach it with counter sunk machine and wood screws. Blocking for the screws was added for this purpose. This blocking can be seen along the sides and down the center of the hull in this picture.
What size is your motor? It almost sounds like maybe it's not the right one for running that ducted fan. I know I've melted a couple of motors and esc because they had the right kv's but just weren't big enough to handle the loads in a couple of my jet drives.Comment
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What Kv is your motor that you are using?Well. I charged up the battery(s) and ran it again.
It ran good, but still overheats! This time, I ran it for a few seconds more that the 26 second video shows. The ESC got so hot that the solder joint on one of the connections (at the ESC) melted. I checked it and it was 180°F+ (82°C). The battery was just as hot.
Not sure what to think at this point except to get a higher amp ESC.Comment
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Just saw your video. That thing is awesome in the snow. You need to try some jumps.Comment
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It kind of sounds like maybe you have too high a kv motor for this fan. From the link you posted on page 1 to Hobbyking I copied this:
Recomended Motor: 36-70 5 Turn (14.8~22.2v)
ESC: 50A
Rpm: 2,000kv
Power: 1,000~2,500g Thrust
Even if you went to a higher esc I think your motor would fry if not the esc and battery too. I'm not an expert though especially concerning ducted fans just looking at what the specs are showing.Comment
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There's your problem!!
3,000 is about the max Kv for the fan in an airplane where the motor can unwind and reach a higher rpm once in motion. In your airboat, your never going to reach 100mph, so you need a motor with more torque to spin the fan.
If you have any lower Kv motors, try those. An XL can would even work, the more torque the better. You can try stepping it down to 3s, but im not guaranteeing anything.
On a side note, the ESC looks like it'd doing a great job, no cogging or anything. Your probably getting really close to the 100a draw, possibly more. That would explain the overheating. Otherwise, car esc's actually do a great job at stuff like this. Your fan is going to be a lot smoother to control than a 4wd buggy doing stop and go all day long (race).Comment
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