Alan Pennington Posted July 28, 2014 Share Posted July 28, 2014 Hi need help please? I have a 600 brushed electric motor in a glider and I'm thinking of changing to brushless continent. How do I find out which size do I need ie is there a table I can go to which will give me a size I can use. Thanks Alan Quote Link to comment Share on other sites More sharing options...
PatMc Posted July 28, 2014 Share Posted July 28, 2014 Alan, there's no real direct comparison particularly if the brushed motor used nickel cells. Bear in mind that a brushless motor giving the same power will be lighter whilst one of the same weight will be potentialy much more powerful. Best post details of the battery & prop used with the brushed motor, in fact why not say which model or give it's size & present AUW. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted July 28, 2014 Share Posted July 28, 2014 Yep, agree with Pat.....there is no real comparison. Start from first principles such as the weight & the type of model & I'm sure good advise will be forthcoming Quote Link to comment Share on other sites More sharing options...
Alan Pennington Posted July 28, 2014 Author Share Posted July 28, 2014 Thanks PatMc and Steve. I was just going through the forum and just put up a post. I will blow the dust off the glider and give full details, as it has been such a long time since it has seen the light of day I was thinking of giving it an airing as there is a field at the back of our house which has just been cut for hay and is doing nothing. Thanks for quick responce Alan Quote Link to comment Share on other sites More sharing options...
Alan Pennington Posted July 29, 2014 Author Share Posted July 29, 2014 Hi again I have blown the dust off the glider. It's a Irvine Early Bird it has a wing span of 1.8m and the weight with an 1700mah 8.4volt nicad batt comes out at 1475g. So any help with information as to what setup I need would be a great help. Quote Link to comment Share on other sites More sharing options...
PatMc Posted July 29, 2014 Share Posted July 29, 2014 Hi Alan, I bought a S/H Protech Unlimited with a spare bashed but useable fuselage some time ago. I'm almost certain that the Early Bird used the same blown plastic fuselage & tail feathers. The Unlimited had a 600 motor fixed to a plastic mount by a metal strap, the mount was secured to the fuselage by 2 PK screws either side & a third through the nose ring. It was(is) an aerobatic "warm liner" about 1.6m span but I fitted a spare 1.8m polyhedral wing to the spare fuselage & fly that as a thermal model. The attached photos show the both versions, the original canopies were broken & I made fibre glass replacements which are slightly different shape. If these fuselages & tails are the same as your EB let me know & I'll post some details of the mods I made to install the motors & batteries. There are already some photos in my album in "My E-Gliders" section that might help. Unlimited with brushless inrunner & 2200mAH 3s lipo - AUW 1165g. Igor, uses same fuselage but with 1.8m wings, E-power 2815/920 brushless outrunner & Gens Ace 1550mAH 3s lipo - AUW 950g. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted July 29, 2014 Share Posted July 29, 2014 Remember that 7 cell SC pack will weigh a fair bit Alan so you will lose a fair bit of weight switching to Lipos....weigh the current flight pack (probably around 450g) & compare it with a 1300-1500 mAh 3S Lipo (probably around 130g) Quote Link to comment Share on other sites More sharing options...
fly boy3 Posted July 29, 2014 Share Posted July 29, 2014 Hi Alan, I am a newbie to electrics, but I think you will have to use a brushless ESC if you do change motors, bet you knew that though. LoL Cheers Quote Link to comment Share on other sites More sharing options...
Alan Pennington Posted July 29, 2014 Author Share Posted July 29, 2014 Hi PatMc Yes your Igor is some what like my EB. I took a photo of my EB but having a problem uploading it, my fault so will have another go tomorrow so you can see it is close. Quote Link to comment Share on other sites More sharing options...
Alan Pennington Posted July 29, 2014 Author Share Posted July 29, 2014 Hi PatMc I have now got the photos. Sorry for the cat he's called Merlin and only 1year old so everything has to be checked out Quote Link to comment Share on other sites More sharing options...
PatMc Posted August 6, 2014 Share Posted August 6, 2014 Hi Alan, not sure if I'm too late with some more detailed photos of the mods I made to Igor's fuselage but here goes anyway. First I removed the existing plastic motor mount. The fuselage nose ring is sandwiched between a beech ply disc (thickness to suit spinner/collet) & a fibre glass disc. I used a cheap (Aldi) hole saw to cut the discs, then enlarged the central hole. Glue doesn't hold to the fus material but a drop of cyano holds the inner disc temporarily in place whilst the motor is fitted. This agricultural piece of 1/8 beech ply was used to hold the rud & elev servos when the fus was used as a slope soaring, it now helps to maintain stiffness now that the motor mount has been removed. The piece of plastic sticking up was cut from scrap material heat bent to shape. It's cyanoed to the existing plastic frame & acts as the battery front stop, it's overhang is flexible enough to clip the battery in place. The Rx is housed in foam plastic under the battery rear stop which is cyanoed to the original plastic frame. Note - the position of the battery was decided in order to get the cg about right before the two stops were actually cyanoed in place. No nose weight has been found necessary. General layout showing the smaller servos fitted to a couple of plastic cross pieces cyanoed to the original frame & bowden cable used in place of the push rods. Shows how the battery fits. The esc is left unfixed underneath. Battery rear stop is clearer in this photo. The fuselage is moulded with some right thrust which means there's more clearance for the motor wires on that side - something to bear in mind when fitting the motor. As an extra precaution I've cut a length from a largish cable tie, sprung it into place to hold the wires against the fus. It's secured by a couple of self tapping screws through the holes meant for the original motor mount fixing screws. Once the canopy is in place the rough & ready interior isn't apparent & though the model's still no beauty it has a surprisingly good performance. Quote Link to comment Share on other sites More sharing options...
Alan Pennington Posted August 8, 2014 Author Share Posted August 8, 2014 Hi PatMc No it's not been to late. That has been a great help. Cheers Quote Link to comment Share on other sites More sharing options...
Alan Pennington Posted August 9, 2014 Author Share Posted August 9, 2014 Hi PatMc You say that you used an e-power 2815/920 in your Igor. Not knowing how the details work, does 28 mean the diameter don't now what the 15 stands for and the 920 is this the kv? I have been looking on Hobbyking web site for the same size motor I think. It says it's a Ntm prop drive series 28-26 1100kv/252kw. Product code NTM2826-1100. How close is this to yours? Alan Edited By Alan Pennington on 09/08/2014 14:54:56 Quote Link to comment Share on other sites More sharing options...
PatMc Posted August 9, 2014 Share Posted August 9, 2014 Hi Alan, I'm not sure how the E-power reference numbers work, the 2815/920 is bigger than 28mm dia but it is 920kv. Here is the power combo I use - all bought from Giant Shark : e-max motor, 25A ESC, 1550 battery I also got this 40mm spinner & fitted it with Graupner 9x5 blades. At full power this combo pulls 21A, 250W @ 9600rpm. I only ever have full throttle for 30sec bursts (enough to get the model to 200 metres +) I haven't had any problems with the ESC but the current margin might be considered tight so I think this 30A ESC would be a good alternative. IIRC the shaft was as shown in the GS photos & had to be reversed. An alternative motor, I think worth considering, is this HK Gliderdrive. It's about the same dia but without a rotating case to worry about, a bit longer, slightly heavier & roughly the same kv. If you buy from HK this Plush 30 ESC is probably identical to the GS one & there's plenty of suitable lipos to choose from. One problem I've noticed that GS are out of stock of the spinners & only HK's International warehouse stock any suitable 38mm or 40mm ones. Quote Link to comment Share on other sites More sharing options...
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