Simon Kirk Posted February 18, 2017 Share Posted February 18, 2017 Hi guys some of you may remember my thread last year about power set ups and trying to learn the ropes....I didn't want to resurrect the thread as it would get confusing so here goes....Iv not had chance to get my head around choosing power setups as I started a new job back in may on the railway and have spent the last year learning all there is to know there, I'm wanting to build the alpha jet mk2 and was wondering anyone could please recommend me a power set up? Ideally as cheap as possible (maybe hobbyking?) My plan is to build it for something to do and then learn about choosing power set ups later on once iv done my first proper build.Thanks in advance Quote Link to comment Share on other sites More sharing options...
Keith Berriman Posted February 18, 2017 Share Posted February 18, 2017 Hello Simon. You will need a 200 watt 2200kv motor on a 30 amp ESC driving a 6x4 prop. A 2200 3 s lipo up front for a little weight to penetrate the wind and elevon control on the elevator's. It will need full throttle for take off and the ease back to 3/4 throttle to cruise around keep it high and only glide in to land Quote Link to comment Share on other sites More sharing options...
Simon Kirk Posted February 18, 2017 Author Share Posted February 18, 2017 Thanks mate.What I was getting at was the whole process of choosing an actual motor and esc etc was confusing.Is there any chance when youv got a minute spare you could link me to a suitable motor and esc combo plz? Quote Link to comment Share on other sites More sharing options...
Simon Kirk Posted February 18, 2017 Author Share Posted February 18, 2017 It's the whole thing of getting the correct Amps and speed controler that baffles me.I'm usually technically minded but this has confused the hell out of me for a long time, there's just so many motors with the same kv ratings but differ so much with motors and wattage etc Quote Link to comment Share on other sites More sharing options...
Keith Berriman Posted February 19, 2017 Share Posted February 19, 2017 May be look at his link for an alternative kit -- built, flown, tested good links to supplier https://bmfa.org/class1/id/39195 Quote Link to comment Share on other sites More sharing options...
Simon Kirk Posted February 19, 2017 Author Share Posted February 19, 2017 I'd still be stuck on the closing of motor and esc though.I prefer the looks of the alpha jet too Quote Link to comment Share on other sites More sharing options...
Simon Kirk Posted February 19, 2017 Author Share Posted February 19, 2017 I'd still be stuck on the closing of motor and esc though.I prefer the looks of the alpha jet too Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted February 19, 2017 Share Posted February 19, 2017 Requires 250 watt Motor, 25amp ESC, 3 x 9gram servos, 8 x 4 prop to complete Simon Look on BRC Hobbies Or 4Max Quote Link to comment Share on other sites More sharing options...
Keith Berriman Posted February 19, 2017 Share Posted February 19, 2017 Trying to simplify your appreciation let's try this The weight of the model is a start point with 100 watts per pound basic 150 watts per pound acrobatic 200 watts per pound going vertical or very acrobatic. Then the type and size of the model determines the prop required, larger props require lower kv motor smaller props require higher kv motor. Link this with watts required and look for a motor to fit the bill. This then gives you the watts as a guide line. Divide the watts by an average of 10 volts on a 3 S lipo battery to get the amps and the allow 30% extra to get to ESC required. Because the alpha jet is limited in prop area that's why you needa high revving motor and small prop. The lipo capacity is the determined by whatyou can get in the model and how long you want to fly. Edited By RC Plane Flyer on 19/02/2017 17:46:29 Quote Link to comment Share on other sites More sharing options...
Simon Kirk Posted February 20, 2017 Author Share Posted February 20, 2017 That makes loads more sense than what iv read in the past mate cheers! Il have a look and try find a combination and post here to see what you guys think Quote Link to comment Share on other sites More sharing options...
Simon Kirk Posted February 20, 2017 Author Share Posted February 20, 2017 I'm struggling to find an affordable 2200kv motor so iv found this.... https://hobbyking.com/en_us/d2826-6-2200kv-outrunner-motor.htmlHowever it's 342 watts which is well above the 200 you recommended, would this make it too powerful for the model?Also says 5x5 prop recommended for a 3s pack.... This is all so confusing lol Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted February 20, 2017 Share Posted February 20, 2017 More important Simon Get a 180w - 200w motor, and I think you will find they are about 1000kv The 2200 kV is hard to get where I searched in the 200w range Quote Link to comment Share on other sites More sharing options...
Keith Berriman Posted February 20, 2017 Share Posted February 20, 2017 Try BRC Hobbies there is one there at 280 watts 2200 kv but thats on a 6x5.5 and 190 on a 6x4 they have a reasonable priced 40 amp esc Edited By RC Plane Flyer on 20/02/2017 20:11:23 Quote Link to comment Share on other sites More sharing options...
Simon Kirk Posted February 21, 2017 Author Share Posted February 21, 2017 OK cheers il take a look, so presumably I'd need to run it on a 6x4 so I got close to the desired 200 watts? Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted February 21, 2017 Share Posted February 21, 2017 Remember Simon Approximately 100w per pound model weight for ample power It is not critical, as I fly some EPP foam at 50w lb, but they don't fly vertical. For aggressive 3D, look to 200w per lb, unlimited vertical performance Very popular lipos appear to be 2200mah and 3300mah, or thereabouts They can be 1800mah and 2600mah and still fly your model These sizes will determine how long you are in the air, usually in the order of 6 to 8 to 12 minutes And on a motor glider, with care, 20 minutes or more Nothing is critical yet The ESC is chosen to embrace and encompass the sustained amperage drawn by the motor If a model measures 32amps draw, then you don't go out and buy a 32amp ESC You fit a 40A ESC to cover the maximum possible current What you don't do is fit a 20 amp ESC Most suppliers will advise especially 4max Quote Link to comment Share on other sites More sharing options...
Simon Kirk Posted February 21, 2017 Author Share Posted February 21, 2017 Thanks mate the bit that confused me more than anything is knowing what kv motor to use but on most of the plans it states what size prop and kv motor to use, so by taking this info and the models weight I can use the info posted above to work it all out.... I think I'm starting to get it lol.I read about wind loading and surface areas and stuff, does that matter so much if using the watts per pound measurement? Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted February 21, 2017 Share Posted February 21, 2017 Luckily Simon, the correct electric set up usually pans out within the design limits of a model when chosen Within the 100 watts per lb power requirement. A 2lb model would be considered light by most You will be OK working around 200w Quote Link to comment Share on other sites More sharing options...
Simon Kirk Posted February 21, 2017 Author Share Posted February 21, 2017 Thanks a lot for your help gents. So iv come to the conclusion of using this motor....http://www.brchobbies.co.uk/catalog/product_info.php?cPath=103_49&products_id=811 with a 6x4 prop (190watts)And this esc http://www.brchobbies.co.uk/catalog/product_info.php?cPath=15_95&products_id=1309Would this be suitable for the alpha jet mk2? Should I maybe look at altering prop size slightly to try get those extra few watts or will 10 not make much of a difference?Cheers Quote Link to comment Share on other sites More sharing options...
Keith Berriman Posted February 21, 2017 Share Posted February 21, 2017 There has to be a start point and only when built and flown and tweeked can you can start on trying different propsand watt meter checks to better the performance . I started on a 6 x4. Then changed to 7 x4 and it was a dream to fly and control Quote Link to comment Share on other sites More sharing options...
Simon Kirk Posted February 22, 2017 Author Share Posted February 22, 2017 OK brilliant so il build with that set up and the 6x4 and then see how flies and alter the prop set up If needs be will be ordering a watt meter along with the motor and esc Quote Link to comment Share on other sites More sharing options...
Simon Kirk Posted February 28, 2017 Author Share Posted February 28, 2017 OK all cut out, motor and servos fitted but having trouble with control horns on the elevons, I used a couple of spare mpx horns I had spare with the little adjustable grub screw on them.Fitted all up and the servo seems to push the rod past the horns limit and has pulled it clean off the elevons. Can anyone recommend any control horns that or ways of mounting them that will make them stay on the elevon? I was thinking of getting some of the ones that push through and snap together?Cheers Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted February 28, 2017 Share Posted February 28, 2017 Reduce the throws Simon, while you are setting up so as not to strain anything I set my servos to 80% travel while I test everything, then turn them back when sure no damage is done Quote Link to comment Share on other sites More sharing options...
Simon Kirk Posted February 28, 2017 Author Share Posted February 28, 2017 Cheers Denis I was testing with a servo tester as no plug in esc yet (my soldering iron turned up today and didn't work) are the push fit horns going to be the best type to use in depron? I just can't seem to find a glue that makes a string enough bond for stick on horns.Have tried por and epoxy and neither seems to adhere to the depron properly Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted February 28, 2017 Share Posted February 28, 2017 UHU por, put a coating on each surface, and leave for 10 minutes then push in, this can be very strong if done right Also foam safe superglue, again, not stored cold, warm and used sparingly It is the foam that is weak and needs careful handling Also, you can buy serrated horns with a backing clip, that grips when pushed on, I will look them up Edited By Denis Watkins on 28/02/2017 21:22:15 Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted February 28, 2017 Share Posted February 28, 2017 BRC Hobbies Quote Link to comment Share on other sites More sharing options...
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