Steve Hargreaves - Moderator

Chaps, as Nigel & others have mentioned this thread is in great danger or re-running the circular arguments in the Electric Car thread. Let's not go there eh? I'm not sure the servers could cope

The new address is in Coppull nr Chorley, not a million miles away from me so I might have to take a looksee..... I know the site & it's not really an industrial manufacturing type site...more small offices & lock ups....so it seems unlikely that production is going on there. Clearly the address given might be the sales outlet with the product being manufactured elsewhere....

Nikola Tesla was also an absolute genius who was so far ahead of his time it was difficult to comprehend. One reason he went bankrupt was his decision to release Westinghouse from the patents/contracts agreement he had with them as they were on the verge of bankruptcy. Had he pursued them & had Westinghouse been around to pay him I read he would be worth around $43 billion in today's money..... He was an amazingly clever man & we owe much of today's electrical infrastructure to his ideas.

Posted by Will Anderson on 26/02/2019 23:06:09: After a chat with the instructor at the local club, Iv'e decided to keep the IC engine instead of electric. He suggested that you have an extra sense to hear the model in case you lose sight of it (in the sun for instance). Something thats more difficult with electric. So I'll box up all the leccy bits for a later project. Iv'e had plenty of years experience in my youth, building and tuning 2 stroke twin motorbike engines. So how hard can it be with a wee couple of CCs single? I'd never thought of it like that but I think your instructor does make a valid point....by listening to the sound of the engine you can often tell if the model is climbing or diving from the sound of the engine. Certainly not hard to operate a glow engine but it does take a little skill...you'll be well on your way to mastering it if you've been into 2 stroke bike engines (RDs or LCs perhaps...? ). Best advice is to ask the guy who turns up...starts his engines first or second time, flies without incident & goes home.... Look forward to hearing about your first solo....

It doesn't really matter if it's Watts or burning methanol driving them.... spinning props hurt & are best kept away from fingers or indeed any soft fleshy parts....

Hi David & Welcome to the forum...... Not a glider guider myself but I'm sure someone will be along shortly who can help....

Looking good Will.....you're well on the way now....enjoy your new Hobby & don't forget the only stupid question is the one you don't ask. @paul coleman 1....Hi Paul, welcome to the forum. It might be an idea to start your own thread rather than hijack another newcomers thread. Tell us a bit about yourself, about the clubs around the Leeds area. It might make it easier for Sonny Monks to find you too.....

Paul, the free plan was in the October 2015 issue of the magazine see here & note the link in David Ashbys post to the corrected page 2. The plan was for a balsa wood version; what Stephen has done is to "modify" the plan & make the Bambino out of depron foam & a beautiful job he has made of it too.... The original plan contains no information on how to do this (but I'm sure Stephen would be happy to share a few pointers...)

Posted by Rocker on 24/02/2019 08:58:32: Thanks I take your point about the time it will take to charge a lipo up at the field Most of the people at my club take a 12 volt battery with them and charge up their lipo on anything from 5 amp up to 10 amps .I am not comfortable with that and only like to charge at 1 amp so considering how long it will take to charge a lipo at 1 amp I think I would be better using the money to buy some more lipo then Charging a 5000mAh LiPo at 5A is only 1C...10A would be 2C & most Lipos will take this easily. At 5A your LiPo will be charged in about 1 hour.....at 10A about 30 minutes. Charging at 1A is only 0.2C & would take approximately 5 hours to fully charge your LiPo Rocker by which time it will be dark....

The best way to work it out is to use the concept of "Watt-Hours" as a representation of the energy stored in the battery..... To make the maths easy lets consider a 100Ah Leisure battery this contains 12V x 100Ah equals 1200Wh of energy.....so if we take Rockers 6S 5000mAh (or 5Ah) battery that's 22.2V x 5Ah equals 111Wh of energy..... 1200 divided by 111 equals 10.81 charges....simples.... Now come the caveats.....first one...no charging is 100% efficient so you'll lose some energy there....lets say the process is about 80% efficient....second one...the Lipo won't be completely flat when you come to charge it....most people aim for about 20% capacity left at the end of a flight (so this kind of cancels out the loss of efficiency).... third one.... as others have said lead acid batteries really do not like being fully discharged.....Deep cycle batteries (which leisure batteries are supposed to be) can stand it better than say ordinary car batteries. Fourth one...they are flippin heavy...a 100Ah battery will be something like 20kgs plus....is the field far from your car? A good source of Leisure batteries is here.... no link other than being a satisfied customer.... Check out their range of Lithium leisure batteries too.....100Ah...£1,000....bargain... Hope that helps....

Posted by Will Anderson on 18/02/2019 17:51:27: My radio has a function to reduce servo travel. So if, for example, I was to set the throttle at 75% would this work with the ESC? The radio is a Futaba T6X Super Definitely not...as others have mentioned set up the ESC as per the instructions so you can be sure you are getting full power & the idle/off will be at the right point. If you find you have too much power then throttle back....that's kind of what the throttle stick does... Oh & whilst you are setting up take the prop off the motor. That way if the motor starts up by accident then no big deal...if the prop is attached then it can really spoil your day/fingers. Sounds like you are getting there Will.....not long until the model is in the air I hope....

I would say go & try it....yes you are a handful of watts down but as you say there is lots of thrust & I'm sure there will be enough to fly it....after all these are full power figures & you rarely fly on full power for long. The two blade prop will be slightly more efficient than the 3 blade & at 15" diameter will be moving a larger column of air so you may even find it flies just as well on less input power which will equate to longer flight times.... The weekend weather looks very good so as a wise man once said "Don't just stand there...get one up!!" Just watch the ground clearance as that prop tip is now a whole inch closer to the ground.....

I'd use what you can lay your hands on Simon....if only to guide you in the right direction. Eprops possibly a tiny bit more efficient & certainly lighter than an equivalent IC type prop so probably worth fitting at some stage.....

I think a 1" increase in diameter to compensate for the "missing" blade is a little conservative. I seem to recall a rule of thumb something like going down 2" in diameter & up 1" in pitch when converting from a two blade to a three bladed prop. If we reverse that logic a 15x6 would be the appropriate size two blade prop to replace a 13x7 three blade. Simon's figures would certainly indicate that a 14x7 is too small as his power has dropped away significantly. To get the power back Simon you need to increase the load on the motor...which means a larger prop......I'd try a 15x6 or a 15x7 & see how that works out.....do you have the ground clearance for these sizes? Ironically the main reason for full size multi-blade props is to allow a smaller diameter prop to be used so that ground clearance can be maintained. Imagine the diameter required for a two bladed prop fitted to a full size Corsair....

Check all the wood to wood joints too Luccaaa.....ARTF manufacturers are not noted for their liberal use of glue so now is the time to check sufficient has been used. If in doubt wick a bit of CA into the joints. Gussets can add a huge amount of strength for very little weight. Check the firewall too & you might consider pinning it in place with a couple of cocktail sticks either side (drill 1.5mm hole through the side & into the firewall....dab of white glue or epoxy & tap a cocktail stick into the hole. Trim off & sand) Adds masses of strength & no weight.....

Posted by brian sylvester 1 on 11/02/2019 14:07:07: had broken crankpin on my asp 91 fourstroke now rebuilt with new crank ..... brian Blimey Brian that IS a coincidence.....I rebuilt MY ASP91 fourstroke that had suffered a similar fate this weekend.....new crank, con-rod & bearings (the ones in it felt OK but I can't help feeling the rear one was probably full of aluminium shavings) Not run as yet but turns over nicely....

Can you not simply adjust the ATV of the flap channel to get the amount of movement you want?

Posted by Robert Welford on 08/02/2019 15:46:45: Use carbon paper under plan and trace through - gives mirror image on reverse side! This is what I do.....use the carbon paper "carbon side" up though so the lines you draw over on the plan side appear on the rear of the plan.... As others have said all you really need are the spars LE/TE & ribs.....

Posted by Nigel R on 07/02/2019 17:36:16: After cunningly building a fuselage upside down for some reason, I then proceeded to build in upthrust. I managed to build in some left thrust to a fuselage once......my excuse was that the fuselage had to be built upside down......

Both electric & IC power have pluses & minuses Will, it really depends on you & what you enjoy. It's your hobby after all...you're supposed to enjoy it. Personally I like engines & get great satisfaction from running them. I find electric power a bit soul-less but will readily acknowledge that it's clean efficient & convenient. But that's just me..... Choose whichever power source appeals to you....both will power your model well & one is not "better" than the other....

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 )

Posted by Unichap on 03/02/2019 12:53:40: I don't intend using the cowl - as I'm putting a nice 4 stroke in the model I don't want to hide it under a cowl. Saitos are pretty light & a 60 4 stroke won't be very much different to a 46 2 stroke when you add the weight of the 2 stroke muffler (Saito list the 62 as 420g & an SC46 is 438g so not much in it). I wouldn't worry too much about moving the firewall for CoG reasons.....shifting the battery around should be enough to fine tune it....

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....

I'm sure there's some info in the WOT4 instructions relating the length of the engine to the position of the firewall. What you are aiming to achieve is that the cowl covers the engine with a small gap between the front of the cowl & the rear of the spinner & a reasonable overlap of the front of the model by the cowl to allow for cowl fixing screws. A few minutes with all the relevant parts (fuselage side, engine/mount, cowl & spinner) should tell you where the firewall goes....

For those (like me ) who missed this the first time around & then found it had been withdrawn from iPlayer after 7 days (meaning I missed it TWICE....) this film is available on iPlayer once more for another 29 days.....