Will Anderson Posted February 2, 2019 Share Posted February 2, 2019 Iv'e just bought my first RC aeroplane. It's a 2nd hand high wing trainer, 58" wingspan, film covered balsa construction. Receiver and servos are all installed and it has a 25 glow engine. I would like to convert it to electric power so Iv'e been reading lots of posts on the forum to gain a bit of knowledge (I hope). [img]https://i.imgur.com/b8RijQz.jpg[/img] [img]https://i.imgur.com/jnpQQ6q.jpg[/img] [img]https://i.imgur.com/tEarONW.jpg[/img] [img]https://i.imgur.com/hNS7aT9.jpg[/img] [img]https://i.imgur.com/yI1jlne.jpg[/img] Quote Link to comment Share on other sites More sharing options...
Will Anderson Posted February 2, 2019 Author Share Posted February 2, 2019 Following up from my previous post.... https://i.imgur.com/b8RijQz.jpg https://i.imgur.com/664iCAk.jpg https://i.imgur.com/hNS7aT9.jpg https://i.imgur.com/jnpQQ6q.jpg https://i.imgur.com/tEarONW.jpg https://i.imgur.com/yI1jlne.jpg I realise this is probably more power than I need but I'm hoping that I can restrict the power available with the program card. My hope is that I can transfer the electrics to another more advanced model when I'm more experienced. Quote Link to comment Share on other sites More sharing options...
Pete B Posted February 3, 2019 Share Posted February 3, 2019 Hi Will, Welcome to the forum. I'm sure you'll get plenty of good advice here but I see you have a problem with inserting photos. Have a look at these threads Creating an Album and External Photos in our Forum User Guides section which should help. Pete Quote Link to comment Share on other sites More sharing options...
Former Member Posted February 3, 2019 Share Posted February 3, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted February 3, 2019 Share Posted February 3, 2019 welcome will from me....nice surname there also. Ask as may questions as you want as Percy has said... ken anderson...ne..1....anderson dept. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted February 3, 2019 Share Posted February 3, 2019 Long lost Great Great Grandson perhaps Ken..... Will, you can easily reduce the amount of power produced by an electric set up by simply fitting a smaller prop so if a set up fitted with a 10x6 prop produces say 500 watts dropping to a 9x6 will reduce that to 400 watts (NB these figures are purely to illustrate the point....). But I guess we are a little way off that bit.....start at the beginning, read lots, ask lots of questions & it will all start to become clear.....you could do a lot worse that starting here... **LINK** Quote Link to comment Share on other sites More sharing options...
Former Member Posted February 3, 2019 Share Posted February 3, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Will Anderson Posted February 3, 2019 Author Share Posted February 3, 2019 Thanks Pete for the pointer on posting pics and thanks to others for input. Yes Ken nice surname and forename is good enough for a prince so I guess it's win/win This is my first foray into anything RC. The model is a high wing trainer that was an ebay purchase from a late gentleman's collection. I'm also looking at a flight simulator that will work with my futaba TX to get plenty of practice. Theres also a local club that I will most likely join. The pics below are on my short list for parts shopping. Any feedback would be appreciated. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted February 3, 2019 Share Posted February 3, 2019 Are you sure its a 25 glow engine Will.....58" span sounds quite big for a 25.....might it be a 40 perhaps? Do you know the name of the model at all? If a 25 will fly the model then the motor/set up you have there might be a bit too powerful. On the other hand it looks pretty good for a model of that size. A "40 sized" Trainer is usually around the 5lb mark & a good rule of thumb for electric powered high wingers would be around 80-100 watts per lb. The motor is rated at 60A so if we combine that with a 4S battery that's a max of about 800 & a bit watts......as mentioned earlier we can reduce the size of the prop to reduce the power produced. Do you have a Wattmeter? If not then go & buy one....you can't really do much experimentation in electric flight without one. Another thought.....with the kv of that motor you'll likely need a fairly big prop to allow it to develop full power. (I see a 12x9 is "recommended" but this isn't much use as it depends what battery you use....a 12x9 on that motor connected to a 7S battery will release the magic smoke very quickly I suspect.) How much ground clearance do you have? a 25 is likely to use a 9" prop so much smaller than the electric set up is likely to need..... IMHO you are on the right track here but maybe a little extra thought through some of the "Gotchas" might be useful.... Quote Link to comment Share on other sites More sharing options...
Former Member Posted February 3, 2019 Share Posted February 3, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
PeterF Posted February 3, 2019 Share Posted February 3, 2019 Running the set up through e-calc, an on line electric set up calculator, the Ripmax Quantum 40 motor on 4S battery as you have shown will give an rpm of around 10,000rpm. Run this with an 11 x 6 prop and you will get a current draw of about 37A (well within motor and ESC specs and battery capability) giving just over 500W, which will be good for a 5lb weight trainer. If you then develop your skills, the prop could easily be increased to a 12 x 7 which would draw 52A (still in specs for motor, ESC and battery) giving 700W and aerobatic performance. As others have stated, you can not use the program card to limit the motor output, you do this by changing the prop size. One thing with electric is that the motor tries top turn at the same rpm whatever the prop that is fitted, so if you fit too large a prop it draws too much current / power and blows the motor or the ESC. Likewise, in your case fitting a smaller propeller does not allow the motor to rev faster, if you fitted too small a prop on an IC engine then it would scream. Quote Link to comment Share on other sites More sharing options...
Will Anderson Posted February 3, 2019 Author Share Posted February 3, 2019 Hi Steve I will remove the cowling tonight and check the engine size. The model has graphics saying "Hornet". It has a steerable front wheel, do I just measure from the centre of the spinner and divide the prop size by 2 to check ground clearance? The battery I have in mind is a 4S 5500mah. Quote Link to comment Share on other sites More sharing options...
Martin Harris - Moderator Posted February 3, 2019 Share Posted February 3, 2019 I suspect it may be this model although there seems to be a mismatch in the wingspan - if so, a 25 is massively under the recommended power but there are specs for an electric power train... 0.46 ~ 0.52 Two Stroke Glow Engine 42mm Motor 650kv (EP Version) 3300mAh ~ 4000mAh 4s Lipo Battery (EP Version) 60A OPTO ESC (EP Version) A copy of the manual can also be downloaded here. Edited By Martin Harris on 03/02/2019 13:20:36 Quote Link to comment Share on other sites More sharing options...
PeterF Posted February 3, 2019 Share Posted February 3, 2019 If it is the Hornet noted above, then the set up I gave above with an 11 x 6 prop for starters. The recommended motor has a kV of 650 so would spin the prop more slowly than your 800kV motor, hence keep the prop size down a bit to limit the power output. For ground clearance, you can measure from centre of spinner to ground, but as the nose gear is often sprung with a coil in the wire leg, you need to allow a good 2" of clearance, perhaps more for a heavy landing when the nose wheel bends quite a lot to absorb the shock. Also, if it is the one shown then you will not need to make alterations to the model for the electric conversion as it already has a hatch for the battery between the wing and the firewall. Quote Link to comment Share on other sites More sharing options...
Steve Hargreaves - Moderator Posted February 3, 2019 Share Posted February 3, 2019 Posted by Will Anderson on 03/02/2019 12:58:05: Hi Steve I will remove the cowling tonight and check the engine size. The model has graphics saying "Hornet". It has a steerable front wheel, do I just measure from the centre of the spinner and divide the prop size by 2 to check ground clearance? The battery I have in mind is a 4S 5500mah. Hi Will...yep that's it...a 12" prop is 12 inches in diameter so will have a radius of 6 inches. The 11x6 PeterF alludes to is pretty much the same size prop as the 40/46 glow motor would have used so should fit very well & probably provide the right sort of power (this is where the wattmeter comes in...it fits between the battery & the ESC & tells us how much power is being consumed). If you needed more power then you'd need to fit a larger prop (either in diameter or pitch) to make the motor work a bit harder. If ground clearance gets a bit marginal you can always fit larger diameter wheels too but again don't forget that going from a 3" to a 4" wheel will only gain you another 1/2" ground clearance.... Battery sounds fine....quite a large capacity so probably heavier & physically larger than it needs to be but the model should handle it just fine. Do check you can get it in through the hatch though & if needs be go for a smaller capacity like a 4500mAh or even 4000 mAh.....these should still give you plenty of duration. (In case you didn't know the capacity of the battery in mAh or Ah represents the amount of energy it can hold...& this translates as how long the motor will run for. Hence a 5000mAh battery will hold twice the energy & last twice as long as a 2500mAh battery for a given set up but of course will weigh much more & be physically bigger too. Words & phrases like "compromise" & " you don't get something for nothing" are very useful to remember with electric power ) Quote Link to comment Share on other sites More sharing options...
Will Anderson Posted February 3, 2019 Author Share Posted February 3, 2019 Thanks for the input guys Martin is correct, it is that exact Hornet, thanks for the link to the manual. The engine is a SC 40 and the prop is 11x7. The 1st prop number is obvious but with the 2nd number, does higher mean more pitch = more thrust? If so an 11x6 or a 10x7 would mean less thrust? The 11" prop has just over 2" clearance from ground so I don't think I'll go any bigger. Regarding the wattmeter, is it better to bench test this or install one in the model? Quote Link to comment Share on other sites More sharing options...
Former Member Posted February 4, 2019 Share Posted February 4, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
onetenor Posted February 4, 2019 Share Posted February 4, 2019 Just 2 points A smaller prop Will allow an IC motor to rev faster, Hence the scream. Two / too small a prop won't have enough weight to provide flywheel effect for starting.. Unless of course using an electric starter. Quote Link to comment Share on other sites More sharing options...
Nigel R Posted February 4, 2019 Share Posted February 4, 2019 Will, welcome aboard! If you have a simulator, my biggest bit of advice would be to get as much time in, on the simulator, as you can. It will teach a lot of skills that translate very quickly to the real world. Your trainer looks good. Are you dead set against using the glow motor that is already installed? You might find you get on perfectly well with it. And it may very well be easier to go with what you have, rather than taking on a project to convert it. Quote Link to comment Share on other sites More sharing options...
ken anderson. Posted February 4, 2019 Share Posted February 4, 2019 Will, I would use the ic motor version to learn to fly, it will be a bit a bit more ding proof than the electric set up...ie...bent motor shaft, crunched up lipo's(which will be done for)...with ic you may only have to have some spare props at hand...…and a can of fuel to get straight back in the air.... ken anderson...ne...1...bent props dept. Quote Link to comment Share on other sites More sharing options...
Denis Watkins Posted February 4, 2019 Share Posted February 4, 2019 Posted by Nigel R on 04/02/2019 10:24:56: Will, welcome aboard! If you have a simulator, my biggest bit of advice would be to get as much time in, on the simulator, as you can. It will teach a lot of skills that translate very quickly to the real world. Your trainer looks good. Are you dead set against using the glow motor that is already installed? You might find you get on perfectly well with it. And it may very well be easier to go with what you have, rather than taking on a project to convert it. Will, I totally agree with Nigel above comments, as you already have one viable model. the flight sim Double check the control set up to suit you and your club I had a chap come down last year, he spent three months, on his own, using the flight sim, learning with Up elevator stick to go up and down elevator stick to go down And Up throttle stick to slow and Down throttle stick to speed up the motor. These of course are the wrong way round and he is still trying to unlearn this Edited By Denis Watkins on 04/02/2019 10:36:28 Quote Link to comment Share on other sites More sharing options...
Former Member Posted February 4, 2019 Share Posted February 4, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
kc Posted February 4, 2019 Share Posted February 4, 2019 When you join a club you may find they have better flying times for electric flight ( my club has electric only on Sundays) Electric also means you are ready to go without starting engines so you might get more flying in whilst the glow engine pilots are still playing around starting their engines. Electric is clean and avoids cleaning messy oil off the model before you put it in your nice clean car. Clubs usually have a prefernce for Mode 1 (throttle right) or Mode 2 (throttle left ) and you won't want to learn on a different mode to the rest of the club. So choose your club before you start. Ensure the club you choose suits you as regards type of members and type of models and only choose a club which can offer training. The BMFA website has a list of clubs and their contact details. Quote Link to comment Share on other sites More sharing options...
Former Member Posted February 4, 2019 Share Posted February 4, 2019 [This posting has been removed] Quote Link to comment Share on other sites More sharing options...
Nigel R Posted February 4, 2019 Share Posted February 4, 2019 Posted by kc on 04/02/2019 16:54:28: whilst the glow engine pilots are still playing around starting their engines you've been watching the wrong glow engine users Quote Link to comment Share on other sites More sharing options...
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