Topic: RCRCM SUNBIRD BUILD

Couple of challenges - not much room for fat fingers 

Feels 'purposeful' in the hand - fling it off a cliff time soon 

Pretty little thing init...

I like the lolly stick on the wing MPX. Is that cut to length so it bangs against the flap servo mount to stop the green vanishing into the wing?

Have you tried ripping the paint off yet?  

Picking one up on Saturday,same colour too,what's going on with the stanley knife on the ailerons if you don't mind me asking,looks a bit brutal?

hold on Steve, I seem to remember you are a strict advocate of balancing on the fingers and then chucking off...........

Picking one up on Saturday,same colour too,what's going on with the stanley knife on the ailerons if you don't mind me asking,looks a bit brutal?

I reckon the white wiper is proud of the surface, but lets not jump the gun here, let  enginetorque  tell it his way.

You can't beat getting it from the  horses mouth   

Interesting to see how it goes against the Air One Mini that seems to be available again.

Picking one up on Saturday,same colour too,what's going on with the stanley knife on the ailerons if you don't mind me asking,looks a bit brutal?

Looking fwd to seeing that in action And- was thinking of buying one to replace my now no longer Prodij.

I reckon it should be pretty rapid!

Couple of challenges - not much room for fat fingers 

Feels 'purposeful' in the hand - fling it off a cliff time soon 

Can we expect a review soon? quite keen on getting one of these when funds allow, seems like a cool hide in the back of the car performance model 

Can we expect a review soon? quite keen on getting one of these when funds allow, seems like a cool hide in the back of the car performance model 

You'll find they go better out side of the car, probably best from a slope   

Review in next months AMI with luck and a fair wind

Knife blade down the rudder (not aileron) is to loosen up a tight hinge - with care (unless yer brutal...)!

Lolly stick on MPX plug - that's to support the wires to the MPX green - heat shrink over the lot making 'plugs to hook up to the males in the fus - not a fan of automatic set ups, but if you prefer the latter, just pot the lot up in 'spooge'

The wipers needed dressing but nothing that a bit of patience and care can't sort - it's certainly going to be slippery and quick - flaps are big and getting 90 degrees (which may prove unneccesary) is easy.

Vigour servos fit the wings with heaps of room to spare

You can either have 'meaty' HS85 MG's or the like in tandem, or a ballast tube, but not both - I've gone with HS65 MG on ele and a lil 55 on rudder

Only just enough room for enough lead up front - casting is essential - it's a tight and fiddly build but not difficult or complicated

Sloperacers own loom used - very neat

Weighs about 1 kG ready to go -

hold on Steve, I seem to remember you are a strict advocate of balancing on the fingers and then chucking off...........

Told you Tom - no room for fat fingers 

Talking of which - balanced at 68mm back which is directly in line with the servo orifice edge

just a note that the radio trays available for these shown below in my sunbird are cut out to take 2 savox 0255 digi servos at a about £17 each with an impressive 3.2kg, so you can still have 2 decent servos and the ballast tube.
   Cut out for a 4 or 5 cell aaa battery and room inbetween for almost any modern Rx,

Have you tried ripping the paint off yet?  

Hopefully not - Those Savox are neat and powerful but a 55 is more than enough for that little rudder - good for elevator though, although having said that, if (big if...) the dimensions are correct then on an all flying tail you don't need much torque!

I shall be giving her the 'full welly' test as soon as a decent NW appears on the met 

just a note that the radio trays available for these shown below in my sunbird are cut out to take 2 savox 0255 digi servos at a about £17 each with an impressive 3.2kg, so you can still have 2 decent servos and the ballast tube.
   Cut out for a 4 or 5 cell aaa battery and room inbetween for almost any modern Rx,

I think I'd be keeping away from a AAA 4.8v pack for a 6 servo model. I use the 6v AAA hump configuration in my small mouldie and it works fine.
Just looking at the photo, couldn't you get a square AA pack in there?

Pretty sure you can't get a square AA in - the nose is very round!

Although it's six servo's - they're all tiny with not much current drain - the main job with this bird was getting all the hinges as free as possible so that the cute litte servo's centre well and don't have much work to do, reducing current drain to a minimum.

Oh aye - while I think of it, the position of that all flying tail means that you'll need a very long arm on your elevator servo - put the output on the opposite side of the fuselage so that you can do that. Worry not about the loss of torque, the long belcrank on the tail end means that pro-rata it works out just as short arm would on a shorter belcrank 

just a note that the radio trays available for these shown below in my sunbird are cut out to take 2 savox 0255 digi servos at a about £17 each with an impressive 3.2kg, so you can still have 2 decent servos and the ballast tube.
   Cut out for a 4 or 5 cell aaa battery and room inbetween for almost any modern Rx,

He wouldn't listen to me......

Regarding the use of a AAA - I'm pretty comfortable with it seeing as George DSed his MiniBlade to 147mph with a AAA!!

Z

You're dooooomed! DOOMED I TELL THEE!

I've got an 4.8 800 AAA in an Ocelot, 6 servo's 5 of which are digital, 2 of which are el cheapo so prolly chew amps. I'll get a couple of hours of hard flying out of it before it gets low.

She be reet bee.

I'd be very wary about a 4.8v AAA pack having to power 6 servos plus all the wiring. Consider too when it gets colder and those cells aren't quite as efficient.

If you can't get AA's in there then this is probably the ideal configuration for the model.

6v, 850mAh Instants in a hump formation. The size is right plus the extra voltage will not struggle to power all those servos.

I'd love to take all your orders but unfortunately I'm out of stock   until the next delivery, hopefully soon.

lipo? 

Didn't I read somewhere on this forum that small servos actually can be harder on batteries ?

After all, the surface / forces required are what they are servos don't change that, efficiency of servo might.

That said, it is a small model so drain may well be small - but  not because of the servo size used.

Please correct me if i am wrong, I wasn't paying that much attention during that lesson.

Small servo - small torque - small current drain   (unless I'm missing a trick which is entirely feasible) - anyway it's an Eneloop which is a good 'voltage holder' and a 'whopping' 800 mAh - all R/C batteries used to be 500 mAh (when I were a boy and chips were tuppence a bag.....).

Most models have much more battery than actually needed (no bad thing) - you could probably force a 4 cell AA pack in there if you felt the need and the weight is needed anyway!

Five cells - pointless - both servos and the M-Link RX are good down to a shade over 3 volts and those Vigours and the HS 65 and 55 are blisteringly quick on 4.8 volts 

I always thought that a 6v hump was something that the ladies did when they got lonely...

Anyway, yes even a 2/3A pack will fit but it means that the tray does not extend all the way into the nose as per our normal method. I'm all for those 2/3A packs as I think they are great, but it's just easier to go with the AAA in this case, and I don't have any experience which makes me think that they would be a problem. But it's a free country! 2/3AA might be a nice solution as well though Tom.

Z

I always thought that a 6v hump was something that the ladies did when they got lonely...

Anyway, yes even a 2/3A pack will fit but it means that the tray does not extend all the way into the nose as per our normal method. I'm all for those 2/3A packs as I think they are great, but it's just easier to go with the AAA in this case, and I don't have any experience which makes me think that they would be a problem. But it's a free country! 2/3AA might be a nice solution as well though Tom.

Z

in fairness 2/3aa have a poor max discharge just like AAA.

It was my understanding that faster servos drained current more quickly.

anyway it's an Eneloop which is a good 'voltage holder' and a 'whopping' 800 mAh - all R/C batteries used to be 500 mAh (when I were a boy and chips were tuppence a bag.....).

Ah yes, but those were robust nicads, plus they were AA's. It's not the capacity that we're looking for here but the ability to push through all those volts. Generally the larger the cross sectional area of the cell the better that ability is.

Anyway, each to their own but beware the perfect storm of a cold winter day and high speed crow deployment after a full day's flying. 

Out of interest, does anyone actually use "high speed crow deployment"? Other than a certain someone... 

Z

Ah yes, but those were robust nicads, plus they were AA's. It's not the capacity that we're looking for here but the ability to push through all those volts. Generally the larger the cross sectional area of the cell the better that ability is.

Anyway, each to their own but beware the perfect storm of a cold winter day and high speed crow deployment after a full day's flying. 

Agreed - long and thin ain't a patch on short and fat - tis why sub C's are so good - but the trick with batteries is to charge em just before you go out (seems obvious I know but....)!

She'll be right 

Out of interest, does anyone actually use "high speed crow deployment"? Other than a certain someone... 

Z

It was my understanding that faster servos drained current more quickly.

Yep,  I am 99% certain you are right; I just can't find the previous discussions we've had about this (they might be somewhere on here, or it might be on RCG). From memory it's speed that determines the "real world" current drain; sure if you stall a torquier servo it will draw more current, but that doesn't happen that often during normal flying. It's much more usual for us to bang a couple of surfaces over to an endstop (for snap roll or similar); in this situation peak current will be higher the quicker your servos are. I will have a Google and see if I can find the discussion...

Not the thread I remembered, but it appears a sage once said "DON'T use AAA cells - well hardly ever, they cannot (regardless of claimed capacity) deliver current (wrong shape for that)!"... 

http://www.rcgroups.com/forums/showthread.php?t=908555&highlight=servo+current+draw&page=2

Well HARDLY ever

I claim my five pounds - how will you be paying it  

AAA cells are the worst configuration - no doubts about that - as for delivering current - in this instance I don't need much, so they are also 'good enough' for a tiddler like this - I use AAA Intellects in my DLG with no snags!

Current drain - servo speed - energy in energy out - a big fast servo will draw more than a big slow one and a little fast servo will draw more than a little slow one but a little fast one won' draw anything like the current of a big slow one!

I wouldn't fit AAA's where an AA would fit and I wouldn't fit an AA where a Sub C would fit - needs must! 800 Eneloops are pretty good though - far better than earlier AAA's!

Don't get too hung up on batteries - most crash with flat ones simply because they don't charge them on the way to the slope but a couple of days before - again Eneloops are pretty good at holding charge!

Well HARDLY ever

I claim my five pounds - how will you be paying it 

In Monopoly money!

AAA cells are the worst configuration - no doubts about that - as for delivering current - in this instance I don't need much, so they are also 'good enough' for a tiddler like this - I use AAA Intellects in my DLG with no snags!

Current drain - servo speed - energy in energy out - a big fast servo will draw more than a big slow one and a little fast servo will draw more than a little slow one but a little fast one won' draw anything like the current of a big slow one!

I wouldn't fit AAA's where an AA would fit and I wouldn't fit an AA where a Sub C would fit - needs must! 800 Eneloops are pretty good though - far better than earlier AAA's!

Don't get too hung up on batteries - most crash with flat ones simply because they don't charge them on the way to the slope but a couple of days before - again Eneloops are pretty good at holding charge!

Totally agree - I just fancied winding you up... 

In Monopoly money!
Totally agree - I just fancied winding you up... 

So you're not the Messiah - you're just a very naughty boy

What i'm intending to do with mine,if i can't fit a AA 2000 pack in is secure the AAA 800 with a velcro strap , keep an eye on juice levels and swap for another when/if required,not too much trouble and only a tenner a pop

I had 2 miniblades with GP 1000mah aaa's and never had any issues, apart from the Hitec 5125s they were powering.

I think the Eneloops are likely to hold up well, but as Mike says, I wouldn't be happy flying all day on little batteries and even when flying the bigger stuff, my bottom starts to twitch if it's cold and I've been up a while. I have spent a couple of days wiggling the sticks whilst doing the final touches to the set ups and even though I flattened the TX once, the flight battery was still very healthy - not that this is hugely indicative of what may transpire whilst flying perhaps.

For those that really don't fancy the idea (or do wish to fly one model all day for example) then cutting the tray to suit a AA pack will probably be the way - I think you might just get one in there! and the weight won't hurt anything.

When I made the comments on RCG about AAA's and not using them, it was by way of response to seeing folks sticking them in 6 servo 'full size' gliders, with the advent of the later generation of needle noses - 6 teeny servos, with only 4 working for most of the time (don't think coupled flapperons are going to be needed with this one but we'll see once she flies) won't strain the electricity bill much.

Bunging an ammeter between the battery and RX and wiggling the sticks will give you the current drain on any set up (if you're concerned to that extent) lean on the surfaces to induce a little 'flight loading' and see what the meter says - a quick sum and you'll know how long your battery will hold up - knock a third off for a safety margin and there's your duration.

"Bunging an ammeter between the battery and RX and wiggling the sticks will give you the current drain on any set up (if you're concerned to that extent) lean on the surfaces to induce a little 'flight loading' and see what the meter says - a quick sum and you'll know how long your battery will hold up - knock a third off for a safety margin and there's your duration. "

Thanks- good tip!

you guys... 

The build looks good dude, thanks for sharing 

I look forward to hearing your throughts on its performance.

my bottom starts to twitch if it's cold and I've been up a while

Apologies to the thread police but I couldn't let that one pass.
 

Anyway - Back to the eneloops.....