winchweight Posted December 26, 2007 Share Posted December 26, 2007 Hi guys. I need some advice on a cheaper power train for my Air Blaster. The model should weigh in at about 1.1lb. The suggested (expensive) fit is:AXI 2212/26 brushlessJeti Advance 18amp ESC4 Hitec HS85 mini servos2100mah 3S LipoI would like cheaper, but not rubbish, alternative to the above items please. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted December 26, 2007 Share Posted December 26, 2007 £25 for motor and ESC combo !!As for servos, well the choice is endless, checkout Giantcod for these, and also cheaper LiPo packs ( although personally would stick to decent brand personally ) Quote Link to comment Share on other sites More sharing options...
winchweight Posted December 26, 2007 Author Share Posted December 26, 2007 Cheers Tim. not really understanding the blurb, is that about the same power output as the Axi? Happy Christmas by the way! Quote Link to comment Share on other sites More sharing options...
Erfolg Posted December 26, 2007 Share Posted December 26, 2007 Seems you are targeting the 180-200 watt motor range.I would recommend Giant Cod, BRC or Robotbirds. Look at one in their outrunner range. Axi are very good but expensive. I have HET. Max, E sky, Tornado, Keda,Xtra, Tower Pro, all have been good enough. Like HET the best.I would use a bigger speed contrioller, again budget. Range about 20-30w to ensure robustness, again budget unless doing 3d, helicopter, they need the fine step control, that budgets lack.Erfolg Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted December 26, 2007 Share Posted December 26, 2007 This is more like a 100-120 watt motor ( on 3s Lipo ) and yes Shaun, its almost exactly the same as the AXI you mentioned. The included ESC in the deal I linked to is already more than enough at 20A, and I have used this brand in smaller models with no problems whatsover ( mind you I am on 2.4Ghz ) it really depends on what sort of performance you want and final AUW. Assuming AUW is 16oz then 100Watts will be good, but not ballistic, for ballistic, you want closer to 150 watts per pound. If using a 3s battery, ( and anything bigger will be too much and HEAVY ) then reckon on about 10.5 Volts in use, so to get 150 Watts you need 150 / 10.5 which equals....14.2 ( amps ). You can achieve this by using a slightly bigger prop ( which is more efficient anyway ). You really ought to get a "Whattmeter" or similar to accuratey monitor the Amps. Too many amps, and your motor /esc/ will let out the magic smokethis would also be good choice. Oh, and a happy whatsits to you and yours too - when I am gonna get an invite to fly down at your site?....... with a nice brekky first and of course, sticky buns Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted December 26, 2007 Share Posted December 26, 2007 PS I have some nice, hardly used 3s LiPos from Puffin models which I dont need any more ( 1700 M/ah so a bit lighter than the suggested 2100s ) If interested, drop me an email. Quote Link to comment Share on other sites More sharing options...
winchweight Posted December 27, 2007 Author Share Posted December 27, 2007 Thanks chaps, I'll investigate further.Tim PM on route. Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted December 27, 2007 Share Posted December 27, 2007 "Range about 20-30w to ensure robustness,"Think you meant to say Amps there Erfolg ?? Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted December 27, 2007 Share Posted December 27, 2007 Well for starters, its 12 quid just for postage. You dont have any knowledge of the brand ( although the pentium ESCs are good budget units with a good reputation in the USA ). The KV is a bit high for your application, and woiuld be better swinging a smaller prop than you are using. What if it goes tits up - how are you going to get on returning / querying it etc etc. Although I have bought stuff from Ebay, for something like this, frankly, I would stick with a UK dealer such as Puffin, BRC, Robotbirds, Giantcod etc..... there are plenty of good UK dealers stocking this type of motor at very reasonable prices.The ones I mentioned earlier fitted YOUR criteria of "cheaper but not rubbish" Quote Link to comment Share on other sites More sharing options...
winchweight Posted December 28, 2007 Author Share Posted December 28, 2007 Point taken. What about servos then. Would a Tower SG90 9g servo do the job, or are the BRC minis better? Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted December 28, 2007 Share Posted December 28, 2007 Well the problem with the servos is the torque. If the kit manufacturer recommends the HS85s then I am reluctant to suggest you use a mini low torque job like the 9g sg90. This ( and the BRC minis ) are low torque models for lightweight models with a pull of only around 1.2K/G cm, whereas the HS85s are rated at over twice that - 3KG per c/m.I am not saying they wont work, but you see the problem The following all provide SIMILAR specs of the Hitec ones, but at differing costs.GWS Weight: 17 grams Dimensions: 30.86mm x 16.1 mm x 26.5mm Operating Speed (4.8V no load): 0.13sec/60 degrees Stall Torque (4.8V): 25oz/in (2.4 kg/cm) Operating Voltage: 4.8/6VSUPERTEC MINI /MICRODimensions (mm): 14.0 x 28.0 x 29.8Weight (grams): 28.0Speed (sec): 0.17Torque (Kg.cm): 5.40Ball Raced: Yes SuperTec Park Flyer std.Dimensions (mm): 16.2 x 30.8 x 28.5Weight (grams): 18.0Speed (sec): 0.18Torque (Kg.cm): 2.80Ball Raced: No Try Steve Webbs servo shop for a good range of servos. As I say...'tis the torque specs which are quite high for what is really only a lightweight model ( approx 1- 1.2 lbs right ? ) and only the supplier can inform as to why they specify them.....I dont know the model - is it extreme 3d or summat - with huge barn doors as ailerons and the like ??PS did you get my email re: the LiPos ? Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted December 28, 2007 Share Posted December 28, 2007 Webbies..... Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted December 28, 2007 Share Posted December 28, 2007 Just googled the aeroplane in question, and the recommended servos are HS55 s NOT 85s!These are only just over 1kg/cm servos.......so you sent me on a wild goose chase!cheap and within spec. Quote Link to comment Share on other sites More sharing options...
winchweight Posted December 28, 2007 Author Share Posted December 28, 2007 Hi Tim. Thanks for your help, I must have mis-read the spec I will be emailing BRC on 3rd Jan then, for the motor, ESC and servos.As for the Lipos, I am interested, but I will have to see how the finances are at the start of Jan as the Jag needs new tyres Quote Link to comment Share on other sites More sharing options...
Erfolg Posted January 2, 2008 Share Posted January 2, 2008 TimboYes I have misspelled W for amps, misread Kg for Lbs.I understand your position on servos and their torque. Yet I tend to be a liitle more adventourous with my selection.Why? Because today we often are using two servos to drive the aerolons, where in the past we would use one. Many of us in the dim and distant past used low powered servos by todays standards (Linwood, fleet, Waltron). More in keeping with budget mini servos in pwer, speed and resolution. I have an inherant fondess for the GWS, particularly for the HP version of the type L Park model. I use the Tower 90, and have broke one (maybe not the most robust) although they claim Nylon gears I believe.I have bought a number of Esky from HK (keeping below the £18), which seem OK, but documentation on performance has been limited. I have some reservations.I agree with the notes you have written, with very slight qualification Erfolg Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted January 2, 2008 Share Posted January 2, 2008 Hi Erfolg, the recommendations I suggested were based on the wrong information being supplied. The aeroplane does NOT require the larger more powerful sevos originally quoted, but we sorted this out at the end. I agree that due to the amazing choice and range available these days, we are spoilt! I was just a little reluctant to recommend a lower spec when the post asked for recommendations for alternatives to a particular servo specified. It is always easier to suggest others when someone simply asks " what servo do ya reckon would be OK for "X" type of aeroplane" Quote Link to comment Share on other sites More sharing options...
winchweight Posted January 2, 2008 Author Share Posted January 2, 2008 All parts ordered from BRC. C'mon postie! Quote Link to comment Share on other sites More sharing options...
Erfolg Posted January 3, 2008 Share Posted January 3, 2008 TimboI use a mixture of Brand names, Futaba and Budget. I have trouble identifying any real differences between the budget and big Brands, except price.Some members of our club always seem to have the odd story about a budget widget. Yet are strangely reticent about Brand name failures. I know of at least one big name Czech controller and motor failing (separately). I have seen some equipment failures, which seemed to be due to over-propping, rather than poor design/manufacture issues.I do like to keep things simple and cheap. I just swear by my watt/amp meter, seperate the speed controller/motor from the receiver/aerial.Good advice on equipment, but i think that installation and keeping within operational parameters is very important.Erfolg Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted January 3, 2008 Share Posted January 3, 2008 So do I and was not aware that I had implied otherwise ? Quote Link to comment Share on other sites More sharing options...
winchweight Posted January 4, 2008 Author Share Posted January 4, 2008 well chaps, the parts are here, and hopefully I will be able to fit them tomorrow! Quote Link to comment Share on other sites More sharing options...
Erfolg Posted January 5, 2008 Share Posted January 5, 2008 TimboWe really seem to be getting each other wrong!I was not suggesting/implying anything at all. Just stating how i see the world. many will have a different opinion.Erfolg Quote Link to comment Share on other sites More sharing options...
Tim Mackey Posted January 5, 2008 Share Posted January 5, 2008 Sorry Erfolg...... didnt mean to sound disagreeable I know what you mean .... Quote Link to comment Share on other sites More sharing options...
winchweight Posted January 5, 2008 Author Share Posted January 5, 2008 Ahhh!! Sweetness and light resumes Quote Link to comment Share on other sites More sharing options...
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