6ft Fast Electric Mono

[Amp User]

Good question .. Im not sure at this point I can only speculate what a prop of this shape could do. When I get the chance to try one out I will be posting my observations.

[kistinie]

Originally Posted by Amp User

Good question .. Im not sure at this point I can only speculate what a prop of this shape could do. When I get the chance to try one out I will be posting my observations.

When regenerating a propeller need to have a wider Rpm capability as you can sail much faster than you will motor. Most multihulls reach 8 to 10 Knts, average.

Maximum speed is 15 to 25 Knts.
15 is reached by most light 33_40 feet multihulls.
25 is for 2500Kg F40 tri or cat or 6 tons 60" commercial sail boats, mainly cat are they are less expensive

Courage !


About windmill boats are there any operational ones can be seen sailing ?

Or do we need to do a 1/10 to 1/5 scale RC prototype or beach cat, for this summer or solid works and other Catia in winter to calculate effect of gyroscope and behaviour in high sea and wind.?

Can be full mechanical because you will get an efficiency close to 90% with a clean mechanical work , or partially by example torque transmission is mechanical but a generator added and propeller or windmill pitch is assited by a controller. Ride should be very smooth most directions and need low marine skills to drive. A, air and sea propeller pitch computer controlled boat, could be incredibly fast in all sectors. Its my favourite choice.


A challenge could be done this year with 16 feet size limit on boat, 4 to 6 is better to limit the danger and power of these beast. Because pitchpoling a meat cutter is a bad idea.
The effect will be close to an helicopter blade meeting an object. Will cut less as speed lower. Full Lateral frame and minimum intake framing of the air blades should be compulsory to avoid tears.
unframed models reserved for, away from public, use and big commercial applications.

So best would be to do RC boats. All the technology is available, variable pitch included.
Full electric solutions could be tested too.


Ideas invent revolutions but the object does revolution.


Prototyping is vital to valid the ideas.


Have fun ! Try new solutions !

[Amp User]

Well I have obtained two large 7kw brushless outrunners.. there 48v 145A motors. I have two 120A HV controllers made for 48v systems. I have obtained some 150A , 48v Li Poly packs. Good for 30C continuous. I plan to use about 15 to 18hp out of the motors combined this is electrical hp so the torque is going to be insane for there size. I would imagine the torque will be like a 30hp engine. The motors spin at 12,000 rpm at 48v so I will need a 5in dia prop with about 7in pitch. Here's a pic. I plan to run the motors in line with a coupler. The axle's on these are 12mm so will use an adapter to a 1/2in drive to the prop. Think I'm going to use lead teflon bushings in the stuffing box and will inject a load of grease and settle for that. I'm trying to stay lite as possible for all out speed rather then handling on flat water. Lastly is a rigger design I like the sponsons could be removed for towing to the water. The belly area of the tub will be where I sit and motor in front of and then batts between the sponson tubes. FYI that prop was Lazar tached at 34.7k and I made the prop myself. So will use the same design for the big motors. I will actually start with a 6in prop with 7in pitch and adjust it down in dia and pitch till the amps are around 110 for each motor. Im shooting for over all 12ft L x 10ft W rigger with 3in dia carbon booms. All up with motors batts.. 65Lbs. If I can get the tail up with me in it I will be happy. Run time is only 30mins at full throttle. So will only run it hard enough to get on the prop and will feather back till its just staying on the prop hub.

[Amp User]

Found these specs on a known electric trolling motor systems. Here are the stats the highlight is 400watts IN and provides 200W OUT- produces (Kt..or torque of of a 1hp engine). Here's data; this one is 1000W IN and states equal to 3hp engine(out) mainly do to the high torque electric motors provide.

Specifications:
Input Power Watts: 1,000
Output Power: 480 Watts (Comparable to 3 HP gas outboard)
Static Thrust: 68lbs.
Battery Output: 400 Watt Hours
Integrated Battery: Lithium-Manganese (13Ah@29.6V)
Steering Type: Twist tiller
Gearing: F-R continuously variable
Prop Size: 12" x 10"
Weight: 28lb.

[Amp User]

And another 400W In.

Range:
EX.: Ultralight 402 with integrated battery (28.8 V / 8 Ah), Fishing kayak 13.5ft, 58lbs Example of use
Speed in mph Range in miles Run-time in hours

Full throttle
5.8mph
3.5
0:36 mins

Half throttle
3.7mph
11.1
3:00 hrs

Slow speed
2.6mph
15.6
6:00 hrs


Specifications: Input power in watts
400

Rated voltage in volts
28.8

Final voltage in volts
33.2

Propulsive power in watts
180

Comparable gas outboards
(propulsive power)
1 hp

Comparable gas outboards (thrust)
2 hp

Maximum overall efficiency in %
45

Static thrust in lbs
33

Total weight in lbs
15.4

Weight of motor without battery in lbs
9.9

Weight of integrated battery in lbs
5.5

Shaft length in inches
17.7

Integrated battery
230 Wh LIMA

Propeller dimensions in inches
8 x 8

Propeller speed at full power in rpm
max. 1,200

Control
Remote throttle control

Steering
Provision for connection to kayak rudder; lockable

Tilting device
manual with grounding protection

Stepless forward/reverse drive
yes

[Amp User]

Using the above info I could speculate using just one of the gold 7KW engines could provide up to the torque of a 35hp engine. I have two of these motors so double the fun. I have done the math and with the batteries currently I have on hand I can run for 30mins with the torque of a 16hp engine. So far it has cost me 120bucks for 200W hr. In my case I can say approx 1hp per hr. I'm using 30C 5000mah lipo cells. I have basically choice a 8P/6S pack at 6k rpm or 4P/12S for 12K rpm What would be nice would be a 24P/12S system if lipo's grew on tree's.

This pic would need 12k at the prop if I use a 5.5x6in surface prop to hold the tail up.

[marshmat]

The specs sound impressive; alas, the marketing guys have apparently been running on bad math here.

When trolling motor manufacturers say "comparable to a 3 hp gas engine", they're leaving out some very important factors. For example: the trolling motor has a prop optimized for pushing a 2500 lb boat at 2 knots, while the gas outboard has a prop optimized for pushing a 500 lb boat at 6 knots. Obviously, in a test cycle geared towards pushing a big boat slowly, the trolling motor will fare well. Put a comparably optimized prop on the gas outboard, and it will become painfully clear that the prop simply does not know or care what's on the other end of its shaft.

A 7 kW electric outboard could be legitimately compared to a 9.9 hp gas outboard. Given comparable props and similar shaft RPM, these two will perform quite similarly at full power. Neither will come close to a 35 hp gas outboard.

You'll likely find, when you finish working through your propeller calculations, that a much slower turning, much larger diameter prop will make more efficient use of your electric motor's power at the speeds such a boat is likely to operate at. The losses from a belt or chain reduction gear will be more than offset by the greatly improved efficiency you'd get with a larger diameter prop.

Best of luck with the project

[Amp User]

Yes understand and thank you for your advice. I plan on using a small prop for max speed at the loss of some low end out of the hole power. So would rather leg it out a bit to gather as much speed as possible with reasonable run time. In lu of your advice perhaps the new pic would provide better performance as I wont be gearing the motor or using large dia low pitched props. I understood the torque of these motors where equal to 400win puts 200w out makes 1hp of similar torque. It was that torque I'm interested in as I would like to run 12,000 rpm at the prop out of water and hope for 8k unloaded in the water. I'm going to try hand made 5.5inx7 prop first.

[kistinie]

Originally Posted by marshmat

The specs sound impressive; alas, the marketing guys have apparently been running on bad math here.

When trolling motor manufacturers say "comparable to a 3 hp gas engine", they're leaving out some very important factors. For example: the trolling motor has a prop optimized for pushing a 2500 lb boat at 2 knots, while the gas outboard has a prop optimized for pushing a 500 lb boat at 6 knots. Obviously, in a test cycle geared towards pushing a big boat slowly, the trolling motor will fare well. Put a comparably optimized prop on the gas outboard, and it will become painfully clear that the prop simply does not know or care what's on the other end of its shaft.

A 7 kW electric outboard could be legitimately compared to a 9.9 hp gas outboard. Given comparable props and similar shaft RPM, these two will perform quite similarly at full power. Neither will come close to a 35 hp gas outboard.

You'll likely find, when you finish working through your propeller calculations, that a much slower turning, much larger diameter prop will make more efficient use of your electric motor's power at the speeds such a boat is likely to operate at. The losses from a belt or chain reduction gear will be more than offset by the greatly improved efficiency you'd get with a larger diameter prop.

Best of luck with the project

100% ok with you on that
Torqueedo is the industrial proof of this statement

Congratulations Amp U.! Very nice project !

[Amp User]

Thank you Kristine, Its going tobe intresting to see what I can make happen. I have a guy milling me out couplers for the 12mm axles.