HI Peter,
I've just come back from a sail and tried a 40X and 45X prop. On the 40 the motor was getting barely warm after a few minutes and performance was 'barely planing. On the 45X the performance was more sprightly- forefoot definitely out of the water and I was quite happy . After about fifteen minutes the motor was hot to hold after gripping for 5 seconds- not scorching though. is this hot or could I go more? Next time I will try the X50 prop. I reckon I got about 20 mins running with a prop change after about 5 minutes with my 4.3ah cells.
She looked nice bowling along in the autumn sunshine!
Thanks for the help,
Ian.

HI all,
Thanks for the interest. I have done some work on the boat, replacing connectors and putting fuses in and now need to do some experimentation with these different props. I have X and S props from 35mm to 50mm but I think 40-45mm will be good as I tried a 45 S and it went quite well but I don't know how long for, as a connector (Tamiya) failed. it didn't get hot, not running long enough, but when I connected them, one prong had got pushed out of the housing and only just touched. After a minute or two the boat stopped.
By the way, I have used in-line car type fuse holders but have seen clip type holders for glass fuses and also considered blade fuses. I worry about the crimped on wire of these in-line holders. With the open clip ones you can solder on the cable that you are using in the rest of the boat.
There's a lot to learn but, with the help of folks on this site I feel I am making progress. I'm running with 10x4.3ah NimH cells.
Best wishes,
Ian

How hot does the motor get ... go to a smaller prop around 50mm revs will come up heat will go down..
peter

hi, I use a 60mm prop on a the Lesro Javelin with an 850 and planes beautifully. I replaced all connectors with srcewed terminal strips. Every other type just melted after a few mins ! John

HI Robert,
Thanks for that. I have now received a selection of X props from 40mm up to 50 mm so will try some different ones out as soon as I can. I think I spoke too soon about the Torpedo 850 and without much knowledge-always a bad idea! I realise that I was using a mild prop- not and X type.
With regards to connectors, I will bear in mind what you say.
Best wishes,
Ian.

Ian,
As a point of reference, this is the type of prop that MFA recommended for its Torpedo 850. its a 50mm diameter 2 blade "X" type that has quite a steep pitch.

I always use Deans connectors and would not consider anything else.

Hi,
Thanks. I have sent off for some Traxxas and Deans connectore to see which ones I like best. Having done a search on connectors there seems to be lively debate about the relative merits of each. I have also ordered a selection of props to experiment with!
Best wishes
Ian

I would recommend you go for deans connectors. I used tamiya ones in my police boat and they melted within a few minutes, since I changed to deans connectors the boat is a slight bit faster and the connectors don't even get warm.

HI Robert and Dave,
Thanks for your replies- quite a lot to chew on! Firstly I have had problems with my connectors- Tamiya- and plan to change these. I'm looking at Deans and Traxxas connectors.
Secondly I haven't done much experimenting with props so will try out different combinations. Perhaps the prop I'm using is too mild.
The shaft and alignment are good I think- I went to alot of trouble over this.
I take the point about expense with brushless motors with a boat the size of Sea Queen which is why I thought I would stay with brushed motors. I feel reassured, and will start the Sea Queen when I have finished my present project.
Thank you both for your patience, but in my defence my boating up to now has been mainly of the scale variety and if it moved forward I was happy! I would like to gain more experience with faster types of boat- the Sportsman is the first.
When I've got it going better I will post some photos.
Many thanks,
Ian.

HI Ianed57
Robert has correctly identified some of your possible problems. However have you checked for free running of your prop shaft, and is there a thrust washer at the prop end. The motor combination has worked for many others so it should for you.
As a brushless motor user, albeit in a 34" fireboat, I would advise you to have no fear of the motors or the batteries. Yes special chargers and controllers are required and running gear and alignment need to be of a high standard to handle the power.
I buy motors / ESC's direct from China (Compass Store http://stores.shop.ebay.co.uk/Compass-Store__W0QQ_armrsZ1) at a fraction of the cost of uk suppliers, and LiPo batteries / chargers can be obtained at reasonable cost from the Component Shop in the UK. (http://www.component-shop.co.uk/)
Good luck with Improving your boat's performance.
Dave

I'm not sure I follow your comment on batteries?

Brushless motors are no different to brushed motors when it comes to battery chemistry. Both types will run on Pb, Nicad, NihH or Li-poly.

The advantage of Li-Poly is that they are light and can discharge at high C rates. This makes the very usefull for elec R/C park fliers but weight is not usually an issue in boats. Ballast is.

The Sea Queen is a big boat and requires a lot of ballast provided by a 12V 7A gell cell. The Torpedo 850 gives good performance for the cost. A brushless motor thats big enough for the SQ is going to be VERY expensive.

Ian,

I was suprised to hear that you were not satisfied with the performance. How much experimentation did you do with different prop diameters, blades and types (scale or X type)?
This makes a huge difference to the performance.

You may also want to take a look at your connectors as they can restrict the current. I use the two pin Deans Ultra connectors.


Rob