Jon Posted September 4, 2008 Share Posted September 4, 2008 Just about to get an Acro Wot and fit a Electric motor to it...Any body already done this yet?.... I'm looking for any tips / ideas ect...Thinking of fitting a 500w motor plus 5000 mA 4s Lipos.... This will be my 1st low wing after passing the A test...Jon Quote Link to comment Share on other sites More sharing options...
Former Member Posted September 4, 2008 Share Posted September 4, 2008 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Jon Posted September 4, 2008 Author Share Posted September 4, 2008 So, you very old'ens still believe its a black art..eh... Well it'll be born again!Remember WOTs = Volts x Amps ! Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted September 4, 2008 Share Posted September 4, 2008 Tom Sharp 2 wrote (see)acro wots are born to be four stroke powered and to fit lecci would be sacrilegeWOT nonsense Quote Link to comment Share on other sites More sharing options...
Ben Mullins Posted September 4, 2008 Share Posted September 4, 2008 To many bad puns! AAAHHH. I cant take all the WOTTING Quote Link to comment Share on other sites More sharing options...
Former Member Posted September 5, 2008 Share Posted September 5, 2008 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Jon Posted September 5, 2008 Author Share Posted September 5, 2008 Think I'll start once more Just about to get an Acro Wot and fit a Electric motor to it...Any body already done this yet?.... I'm looking for any tips / ideas ect...Thinking of fitting a 500w motor plus 5000 mA 4s Lipos.... This will be my 1st low wing after passing the A test... Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted September 5, 2008 Share Posted September 5, 2008 Right Jon....as I have already intimated in my PM to you, my suggestion is you need at least 100 watts per pound and more like 150 if you want sparkling performance. I reckon that a similar setup to that I used in the WOT4 conversion would be OK, and Danny Fenton also has done a wotty, however these both use LiFes not Lipos. The Acro Wot flies faster than the higher drag WOT4, so should make a nice conversion IMO. I always try to use a large prop as they are more efficient and quieter due to lower revs. I think your 4s pack may just cut it if you get the right Kv motor - its not just about the wattage handling of the motor, you need to get the revs right too. I think you re really looking at least 800 watts minimum for AcroWot style flying. Too high a Kv and a large prop will drink too much juice, and too low a Kv will require a prop thats simply too large in order to get the powr you need. On 4s LiPo your onload voltage will be around 14V and if you are aiming for say a speed of around 50MPH then the following formula shows you need to spin an 8" pitch prop at 7000 RPM. THEORETICALLY (RPM x Pitch)/1056 ( 7000 X 8 ) / 1056 = 53 MPH 7000 RPM / 14volts = 500, so a Kv of around 500 - 600 should be good starting point. Experiment with different diameter props of around 8" pitch and you should be be not far off. For 800 Watts at 14Volts you will need to pull 57A which is little on the high side, but do-able. ESC should be 70A for safety, and you may want to consider a seperate UBEC for radio supply. I always try several different props in conjunction with a whattmeter to establish the power system. "always-broke" here on the forum has also done a wotty conversion and it flew well at the NATS evening line. Quote Link to comment Share on other sites More sharing options...
Howard Tomlin Posted September 5, 2008 Share Posted September 5, 2008 I dont know if this helps but my acro went very well with a 12x6" prop running at about 8,000 rpm on a laser 75. I know you are flying electric but the same principles of prop+ revs = mph speed If you were to get your leccy motor to provide the same performance then you are on to a winner. I repaired mine until it had no chance of holding together in the air - it lasted 18 years!!!!!!! Great plane, I quite miss it to be fair - I have an extra to replace it but the acro was a far more forgiving plane and looked brilliant too. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted September 5, 2008 Share Posted September 5, 2008 That combo would have resulted in a theoretical speed of 45 MPH, so not a million miles away. As I stated, to me, one of the benefits of electric power is the lower noise resulting from ( mainly ) lower prop speeds and to get the speed needed from lower revs requires a larger pitch. However, as is often so, theory and practice often collide.I did end up with a higher prop speed than I would have liked to restore the characteristics of the wotty. Quote Link to comment Share on other sites More sharing options...
Bruce Richards Posted September 5, 2008 Share Posted September 5, 2008 Jon, I electrified a WOT 4 and by building it good and light it flew well no about 600W and I am sure it would fly on 500W. See my tread here.P.S to anyone he is listening Please please please please sort out the search facility on this forum it is so difficult to find an old tread. Quote Link to comment Share on other sites More sharing options...
Jon Posted September 5, 2008 Author Share Posted September 5, 2008 Just had a complete start to finish read of your thread Bruce/Timbo , really helpful.... and thanks for the tips above... cant wait for the summer flying season to start so I can take my test... any idea when it normaly starts as its Sept nowjon Quote Link to comment Share on other sites More sharing options...
Jon Posted September 5, 2008 Author Share Posted September 5, 2008 Have been searching for a outruner for the ACRO WOT to be driven by my existing ESC and 5000 mA Lipos and would really like your ideas / comments on this Motor I'm sure there must be many others to choose from but If posible I would like to use the ESC which I already have, here is its specHi-Model 60-80A Professional ESC SPECS: * Output: 60A, * Max Output: 80A (10 Secs)* Input Voltage: 5.6v - 23v * Lithium Cells: 2 - 6S **See note at bottom* NiMH/NiCad 5 - 18 Cells * Super BEC: YES * Super BEC Output: 3A* Size: W,29mm x L,57mm x H,19mm* Weight: 45g Have I got the sums right Timbo!?jon Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted September 5, 2008 Share Posted September 5, 2008 yes...you may want to add a further cell for real good performance....however it should be OK on 4s. Quote Link to comment Share on other sites More sharing options...
Jon Posted September 5, 2008 Author Share Posted September 5, 2008 Thanks Timbo....think 5s may come when I get a bit more flying time in. i'm still a bit green yet.. I'm still waiting for the so called uk summer flying season to start or did I miss it last month on a day when I had to cut the grass? see I even have my shades at the ready for the A test... Quote Link to comment Share on other sites More sharing options...
Danny Fenton Posted September 13, 2008 Share Posted September 13, 2008 6 cell A123, 600kv Tower pro motor, 70A ESC, jobs a good un Sure it will go on 500 watts, but you will want more when you get into it.Had a quick couple of flights with my wotty this afternoon, and don't usually do flat out low passes but I certainly scared the flightline with its sudden arrival whispering low pass from the right is okay for leccy fliers, might not be loud enough for those IC guys lol Quote Link to comment Share on other sites More sharing options...
Jon Posted September 14, 2008 Author Share Posted September 14, 2008 OK Danny... I fully understand your comments.... but have since come across a 800w which i think I'll use .... however the 500w could be a back up for it! I'll be back..... with photos once I start the build... Jon Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted September 14, 2008 Share Posted September 14, 2008 what Kv is it Jon? Quote Link to comment Share on other sites More sharing options...
Jon Posted September 14, 2008 Author Share Posted September 14, 2008 Hi Timbo Think this is the one we talked about before is it not?.... link its the [b]E-flite 'Power 46' 670Kv (800W) Brushless Motor (EFLM4046A) brc136[/b]ps have you seen my other disapointing post... "How safe is my motor" Quote Link to comment Share on other sites More sharing options...
Phil Reeves Posted October 5, 2008 Share Posted October 5, 2008 Hi guys, Just found this thread, having just decided to leccy my new Acro Wot I wanted to see what others have done. My recent electrification of a Wot 4 mk3 was very sucessful, using an E-flite Power 46, 4s 4400 Lipo and a 13x8 APC "E" it gives me similar performance to my 46ic powered one. I am thinking of fitting one of these http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&ssPageName=STRK:MEWAX:IT&item=320306758665 This motor should give me similar performance to a 70 four stroke on a 14x7 and 4s. What do you think? Quote Link to comment Share on other sites More sharing options...
Jon Posted October 5, 2008 Author Share Posted October 5, 2008 Must say I have not started my build yet... am still at the what to buy stage....My original choice was this Motor Which I already have 2 off ( there was also an 800w combo but it seems to have been withdrawn from the BRC page) but I liked what I saw on your link Phil...... Have you built the plane yet? I have still to buy mine..Had a death in the family which has and still is slowing me down...!jon Quote Link to comment Share on other sites More sharing options...
Phil Reeves Posted October 5, 2008 Share Posted October 5, 2008 Hi Jon,Yes my model is biult and still deciding on how to power it, having got a few ic engines around the hanger to choose from, ASP 65fs, Saito 80, OS 70fs to name a couple. But I have realy enjoyed flying my Wot 4 and so I am seriously thinking electric for my Acro Wot. The link I attached is just one of many motors in the range and as you see come very cheap too, and don't let that put you off, I have been using the Emax series of motors too form China. I have the Vmar X-treme stick LW with an Emax 2826/06 on, a 13x6.5 APC "E" prop, on 4s 3200. This takes off in 15 feet and climbs at 45 degrees, however i only get around 6 to 7 mins from this pack and will try my 4400 4s later. Looking at the specs on your link, I think the Emax 2826 is a little better. Have a look at the attached link the specs given are better than shown, my setup pulls just 28A from the 3200 4s and could perform better still.link Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted October 5, 2008 Share Posted October 5, 2008 Phil...please read this Quote Link to comment Share on other sites More sharing options...
Jon Posted October 5, 2008 Author Share Posted October 5, 2008 Just type a word Phil, Like I typed "Motor" Highlite it and click on the Chain in the row of icons just above.... copy or type the http address in and bobs your elbow! ... I got ticked off when I first put a link in a post tooRe the supply of motors, how do you choose when there are so many on the market and on top of that I'm still no wiz kid with electricery sums either..(thank God for this Forum). at times they seems to defy the Ohms and the Power laws which as a Radio Ham I was convinced that I'd got well and truly under my belt a long time ago.....its a bit of a sweat, this going back to schoolI will be away for a long time next year and not able to fly or build.... so really only have up to then to build and electrify an Acro Wot... I dont want to rush it. but do want to get it done..but really only have till Christmas to finish it.... We are also in the middle of moving home! so am not sure if I should start it or not.... dont life just get in the way some times... Quote Link to comment Share on other sites More sharing options...
Phil Reeves Posted October 5, 2008 Share Posted October 5, 2008 I too have limited time at the moment, as i have just become a Grandad for the second time with another grandchild due in two weeks, still gives me an exscuse to buy another model or two!!! Quote Link to comment Share on other sites More sharing options...
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