Vic8 Posted January 24, 2015 Share Posted January 24, 2015 After giving my starter (Thunder Tigre) a bit of a fettle it occured to me that starters are only rated in volts. Amps or Watts are not mentioned. How do us mere mortals gauge how powerful a starter is before buying, or, have I missed the plot. Out of interest I may obtain an ammeter and measure the current when my starter is working hard . Quote Link to comment Share on other sites More sharing options...
Dave Bran Posted January 24, 2015 Share Posted January 24, 2015 Make it a good 'un!! They likely don't WANT you to know the max power output, but anyway its torque that'll turn your engine, not simply watts. Quote Link to comment Share on other sites More sharing options...
cymaz Posted January 24, 2015 Share Posted January 24, 2015 There are several good geared starters on the market. Or if you are feeling a little flash there is always a Sullivan dynatron. Edited By cymaz on 24/01/2015 22:34:33 Quote Link to comment Share on other sites More sharing options...
cymaz Posted January 25, 2015 Share Posted January 25, 2015 Vic8, sorry, I didn't read your question correctly. How about this....if you don't mind doing the sums! Quote Link to comment Share on other sites More sharing options...
John Privett Posted January 25, 2015 Share Posted January 25, 2015 The sums are straightforward, and it is easy to calculate the input power to the starter. What "the sums" can never tell you on their own is the output power - you need to measure the torque and rotational speed (rpm) to get that. And as it says on that link, "Measuring the torque of the motor is a challenging task. It requires special expensive equipment. Therefore we suggest calculating it." Though I don't know why they suggest calculating it, the best you could do is by assuming a certain efficiency, and that rather defeats the whole object of the exercise! (Not all the input power appears as output power, some will be converted to heat.) Quote Link to comment Share on other sites More sharing options...
Alistair Aardvark Posted January 25, 2015 Share Posted January 25, 2015 Given question has something to do with deciding if a particular starter is able to spin an engine to start it... Torque isn't everything, speed is important too, and this is my experience with plenty of torque but lack of speed. I bought a Just Engines 6.5:1 geared starter for my YS 160. I tried it without fuel and glow to check it would spin over - perfect. However it was nearly impossible to start the engine because as soon as the engine fired it wanted to run faster than the starter, and so kicked back against it. I did find a technique of doing quick 'stab and release' but its nasty. The solution was to run it at 24volts giving greater speed. The impact of the slow speed and kick back was even worse with a Saito 125 - one of the pushrods came out of the rocker arm. Edited By Alistair Aardvark on 25/01/2015 10:46:20 Quote Link to comment Share on other sites More sharing options...
Paul Marsh Posted January 25, 2015 Share Posted January 25, 2015 Just try to hold the motor, like this numpty... Quote Link to comment Share on other sites More sharing options...
Jon H Posted February 2, 2015 Share Posted February 2, 2015 Numpty?? if only that did his justice.. Anyway, I am using the same 6.5:1 JE starter as Aardvark and I think I was the first to ask them to get one after checking the MFR's site on their smaller geared starter. I am running off a 6s (22.2v) lipo and it works a treat. I use it mainly on my large Laser engines (240v, 300v, 360v) which are cowled and cannot be hand primed and started. I also used it on SC 64cc radial and Saito 450 radial as well as a saito 220 and DLE 55. It has not even flinched at any of these engines but you do need to make sure you don't start on the compression stroke as the instant load will melt the switch! Even on 6v though I find it wont start my smaller engines as the engine tries to outrun the starter exactly as Aardvark has described. For me its not a problem as I have a more normal starter in my big box of tools that lives in the car when I go flying, and I rarely need the electric starter anyway. Quote Link to comment Share on other sites More sharing options...
kc Posted February 2, 2015 Share Posted February 2, 2015 What an idiot on that lathe! The good news is the tailstock may well have prevented him from passing on the idiot genes to another generation! It looks like a setup though, but would anyone risk a broken leg or other injury just to make a video? Quote Link to comment Share on other sites More sharing options...
Paul Marsh Posted February 2, 2015 Share Posted February 2, 2015 He was showing off how strong he can be to see if he can hold a stalled motor. Quote Link to comment Share on other sites More sharing options...
Alistair Aardvark Posted February 2, 2015 Share Posted February 2, 2015 Posted by Jon Harper on 02/02/2015 11:59:45: Numpty?? if only that did his justice.. Anyway, I am using the same 6.5:1 JE starter as Aardvark and I think I was the first to ask them to get one after checking the MFR's site on their smaller geared starter. I am running off a 6s (22.2v) lipo and it works a treat. I use it mainly on my large Laser engines (240v, 300v, 360v) which are cowled and cannot be hand primed and started. I also used it on SC 64cc radial and Saito 450 radial as well as a saito 220 and DLE 55. It has not even flinched at any of these engines but you do need to make sure you don't start on the compression stroke as the instant load will melt the switch! Even on 6v though I find it wont start my smaller engines as the engine tries to outrun the starter exactly as Aardvark has described. For me its not a problem as I have a more normal starter in my big box of tools that lives in the car when I go flying, and I rarely need the electric starter anyway. Back to topic... That's Mr Aardvark to you! Quote Link to comment Share on other sites More sharing options...
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