plan ahead for installing r/c kit?

[Tony Harrison 2]

In case you spot all sorts of things going wrong here, it's my first balsa kit-build in half a century... I'm enjoying it hugely, but having to take things slowly since it's not quite like painting by numbers. Interesting challenge to turn 2D plans and sometimes less than comprehensive instructions into an accurate 3D object...

Call me eccentric but as a beginner (still playing with my first r/c plane, a Radian Pro, but not actually flying it, practicing first on the PC with Phoenix) I chose to build a rather old glider kit from a firm that seems defunct: it's an Aquarius 540, 6' span glider for electric power, and I thought it looked pretty plus it seems fairly basic to build.

Even at this early stage I am wondering how far to tinker with the build order. The instructions leave all the electrical & control installation right to the end, and it seems to me I'd be better advised to arrange control runs (about which I am almost wholly ignorant!) etc as I go along...

What do you think? I'm blessed with two very good model shops close by in Newton Abbot - Stan Yeo at Phoenix Models, and John at Bekra, both very helpful guys with good stocks of everything - and I can go there, but I'd appreciate any tips from you knowledgeable folk too.

[IanN]

If you have aileron servos in the wings you're usually pretty much committed to installing those, and the extn leads, as you go

What I generally do for the fus though is to leave the top (or bottom - whichever suits) sheeting off right until the end. I'm then free to play around with the positioning of the gear to get both (a) the c of g as close as possible, and (b) also the easiest / best runs for the control surface linkages to the tail end

[Tony Harrison 2]

Posted by IanN on 26/11/2014 11:43:06:

If you have aileron servos in the wings you're usually pretty much committed to installing those, and the extn leads, as you go

What I generally do for the fus though is to leave the top (or bottom - whichever suits) sheeting off right until the end. I'm then free to play around with the positioning of the gear to get both (a) the c of g as close as possible, and (b) also the easiest / best runs for the control surface linkages to the tail end

Thanks Ian, useful suggestion that makes perfect sense to me. This glider is, as I said, quite old (1980s?), got it cheap on Ebay, and it's elevators & rudder only - no ailerons. Think I'll leave off the lower fuselage sheeting for now.

rgds Tony

[kc]

The Aquarius is still available -right here on Modelflying! It's now sold by MyHobbyStores here

As this is an old design I expect it was made for old motors and nicads but you will surely fit a modern brushless motor and a Lipo. This may well affect the balance as the Lipo will be lighter than the old equivalent nicad pack. So that's something to consider at an early stage. Also Lipo's need removing from the fuselage for recharging / swopping so an easy access hatch is needed. So plan for velcro straps to secure & release the Lipo pack.

I suppose taking the part built fuselage into a helpful model shop to find the right size Lipo & motor might be a good idea.

I am sure that the Aquarius was built by someone here on Modelflying but I cannot find the section.  If you need more info put the model name in your query and someone will surely recognise it and provide some more info.

Edited By kc on 26/11/2014 13:06:48

[Tony Harrison 2]

Posted by kc on 26/11/2014 12:59:19:

.............As this is an old design I expect it was made for old motors and nicads but you will surely fit a modern brushless motor and a Lipo. This may well affect the balance as the Lipo will be lighter than the old equivalent nicad pack. So that's something to consider at an early stage. Also Lipo's need removing from the fuselage for recharging / swopping so an easy access hatch is needed. So plan for velcro straps to secure & release the Lipo pack......................

Edited By kc on 26/11/2014 13:06:48

Thanks kc - interesting that it's still available, odd that they used such a terrible photo and there are no reviews.

I'm sure you're right about motor & batteries. I based the floor height on the single Lipo I own so far, an E-flite 3s I got for my Radian Pro, and it was actually the same as the nominal position marked on the plans. I'll follow your advice re a hatch and quick access. The instructions do not mention any particular motor or battery, which seems a bit vague, but I see there is lots of advice on this site, servos too.

rgds Tony

[Levanter]

Tony. Looks like you are doing fine and taking a well planned approach. Also remember that mistakes can usually be sorted out without being terminal. I rationalise this by calling it practice for the repairs that will surely come later on.

I do see one glaring problem though. Where are the shavings, dust, coffee rings, pets and bloodstains! Crikey!

[Tony Harrison 2]

Posted by Levanter3 on 26/11/2014 15:45:51:

Tony. Looks like you are doing fine and taking a well planned approach. Also remember that mistakes can usually be sorted out without being terminal. I rationalise this by calling it practice for the repairs that will surely come later on.

I do see one glaring problem though. Where are the shavings, dust, coffee rings, pets and bloodstains! Crikey!

Thanks for the encouragement. Re your closing question, my wife's away and I shifted the building board into the living room, which is lots warmer than my zub-zero garage! Trying hard not to create too much mess... No bloodstains so far - is this normal?

rgds Tony

[Andy48]

Following KC's excelent advice, route the motor wires and the ESC to the lipo before the build gets too far advanced. Sometimes the ESC can be a right pain to position, it might not be a problem with a small low powered glider, but it could be with a mode powerful motor. Sometimes the ESC has a ferrite ring near the receiver end of the signal lead. You need holes through the formers big enough for this unless you want some very awkward fiddling to remove the ferrite ring first.

Don't forget to allow some form of cooling airflow though the fus for the motor and ESC too at this stage.

Also think about adding an arming plug at this stage for safety.

[Tony Harrison 2]

Posted by Andy48 on 26/11/2014 22:54:51:

... route the motor wires and the ESC to the lipo before the build gets too far advanced. Sometimes the ESC can be a right pain to position, it might not be a problem with a small low powered glider, but it could be with a mode powerful motor. Sometimes the ESC has a ferrite ring near the receiver end of the signal lead. You need holes through the formers big enough for this unless you want some very awkward fiddling to remove the ferrite ring first.

Don't forget to allow some form of cooling airflow though the fus for the motor and ESC too at this stage.

Also think about adding an arming plug at this stage for safety.

Thanks Andy, valuable details. I think I must buy a motor, ESC and other bits as a priority, so I can follow your advice. The plans usefully suggest apertures to facilitate airflow, and I was already conscious of the need for this. I imagine an "arming plug" is some sort of instant disconnect feature? Maybe a microswitch accessible directly from the outside?

rgds Tony

[Pete B]

To add to Andy's comment, arming are certainly worth considering but not always essential, particularly if you have easy access to the battery by way of a top hatch or the cockpit. All my 'power' models with an underside hatch or where the wing is removed to fit the pack have arming sockets, for which I've used Deans or XT60 connectors.

My sailplanes, with easy battery access, are armed by connecting the battery to the ESC directly. I also have a throttle cut setting on the Tx for additional safety. The Tx is programmed to warn me if this switch is not set on switching on.

Commercial arming sockets are available like this:

As you can see, the system will probably take up a fair bit of space in the narrow fuselage of a leccy glider and adds weight which isn't always wanted.

More about arming sockets here. As you'll read, inline switches are not an option due to the amps they need to pass - and a 30A+ switch is a bit big for us!

Pete

[kc]

It's a completely different model but this photo of the installation (on my electric version of Swamp Rat ) might give you some ideas

The liteply tray has holes for velcro straps& XT60 plugs all cut with a Stanley knife. Extra holes allow plugs and wires to go in several ways if it turns out to be easier when Lipo is positioned after final CG checks. . . Lipo goes on top while ESC goes underneath and has it's own small hatch with cooling slots cut in the 1/32 ply. In this case the motor has a shaft projecting from front and is backplate mounted. Some models need the shaft the other way around so they are internal and fix behind the front bulkhead ( maybe yours will need this) so buy a motor with the wires and shaft the right way round. Shaft can be moved but it's more trouble and best avoided.

Note that, as someone correctly pointed out before, I should have shortened the motor bolts so they won't penetrate the Lipo in a crash.

[Tony Harrison 2]

Posted by Pete B - Moderator on 27/11/2014 12:33:19:

To add to Andy's comment, arming are certainly worth considering but not always essential, particularly if you have easy access to the battery by way of a top hatch or the cockpit. All my 'power' models with an underside hatch or where the wing is removed to fit the pack have arming sockets, for which I've used Deans or XT60 connectors.

My sailplanes, with easy battery access, are armed by connecting the battery to the ESC directly. I also have a throttle cut setting on the Tx for additional safety. The Tx is programmed to warn me if this switch is not set on switching on................

As you can see, the system will probably take up a fair bit of space in the narrow fuselage of a leccy glider and adds weight which isn't always wanted.

More about arming sockets here. As you'll read, inline switches are not an option due to the amps they need to pass - and a 30A+ switch is a bit big for us!

Thanks Pete for explaining this item and for the advice.

rgds Tony

[Tony Harrison 2]

Posted by kc on 27/11/2014 12:52:35:

The liteply tray has holes for velcro straps& XT60 plugs all cut with a Stanley knife. Extra holes allow plugs and wires to go in several ways if it turns out to be easier when Lipo is positioned after final CG checks. . . Lipo goes on top while ESC goes underneath and has it's own small hatch with cooling slots cut in the 1/32 ply. In this case the motor has a shaft projecting from front and is backplate mounted. Some models need the shaft the other way around so they are internal and fix behind the front bulkhead ( maybe yours will need this) so buy a motor with the wires and shaft the right way round. Shaft can be moved but it's more trouble and best avoided.

Note that, as someone correctly pointed out before, I should have shortened the motor bolts so they won't penetrate the Lipo in a crash.

Thanks kc, most helpful - I'd come across this term "liteply" previously, and din't know what was meant by it - you prompted me to Google it, and now I understand. Sounds very useful indeed - I shall visit the model shop and get some. My glider kit specifies balsa for the internal floor separating the RX/ESC etc from the battery but I think liteply is a better bet.

rgds Tony

[kc]

Liteply is the soft ply that is lightweight and often very white in colour ( not always) Stronger than balsa but not a lot heavier, much weaker than Birch ply and DIY shop ply.. Available from model shops and balsa suppliers like Balsa Cabin or SLEC etc. For battery trays it might be possible to substitute a very lightweight piece of DIY ply less than 3mm with some lightening holes to save buying Liteply. But Liteply is a very satisfying material to work with as it cuts so easily.

I use 1/8 inch /3mm nominal Liteply for battery trays etc maybe some non critical formers but never for wing joiners or I.C. engine bulkheads. 3mm can be cut with a Stanley knife ( just) using repeated cuts and possibly cutting from the reverse side too. A scalpel might snap and fly about if used for such heavy cuts. It is so much easier to cut all the holes and some alternative slots for velcro straps whilst the ply is on the bench. Much harder to cut extra holes once installed!

So plan ESC, Lipo, Rx wire fititng at an early stage allowing for alternate positions if needed later. The thick wires from ESC to motor might be difficult to fit in a small space as they dont bend easily and you dont want to cut them short or to extend them if possible.

Balsa floor would probably not take the strain of the velcro straps holding a Lipo during aerobatics.

Edited By kc on 28/11/2014 16:36:25

[Tony Harrison 2]

Posted by kc on 28/11/2014 16:33:53:

Liteply is the soft ply that is lightweight and often very white in colour ( not always) Stronger than balsa but not a lot heavier, much weaker than Birch ply and DIY shop ply.. ...........................

Balsa floor would probably not take the strain of the velcro straps holding a Lipo during aerobatics.

Edited By kc on 28/11/2014 16:36:25

Thanks again kc, very interesting. I shall certainly get some of this stuff - but a quick look around reveals that (rather to my surprise since I've worked with ordinary ply for years) one can get very thin birch ply too. Travis Perkins has a branch near me, used them for years, and see this:

Birch Aircraft Plywood A/B Grade 1525 x 1525 x 1.5mm, Product code: 407000

Don't know the price but it might well be cheaper/better value than similar from a model shop.

rgds Tony

I am pleased and grateful for the valuable information contributed by you and others here.