Yorkman

obvious question-have you 'mirrored' the linkages?both servos will rotate the same way at the same time, but one linkage pushes and the other pulls....

Hmmm, back to that sort of question! I'm looking at max weight 2lbs for a wing loading of 30 oz/sq ft...so-about 250W? Hoping to not go more than 3s lipo.

I've found this old d/f unit which I bought back in the mid nineties-if I update it with a brushless motor is it going to perform adequately (I'm thinking of knocking up an all-foam Vought Corsair as a home for it)? Or has technology far exceeded it and I will be doomed to disappointment?

ok, have come to the conclusion, though it's not mentioned in the manual, that the throttle can not be programmed as the 'slave' channel. If anyone knows different, please let me know!

No prob Timbo, am going to have a further play with mine, see if maybe I can do something with a rudder/throttle mix as the Mossie doesn't have rudder control. Tried using throttle trim this afternoon, which meant making a neckstrap as I never use one! Worked fine tho, even managed to find the switch and cut power completely on short finals to carry out my best 'arrival' with it so far -practise makes perfect

all I can find on the throttle cut programming is off or on.... any thoughts on my mix conundrum outlined above Timbo? Can you try that on the wife's tx and see if you get the same? Ta.

Garry no luck involved-just undercarriages! Can't do that with mine because it's hand launched/belly landed and with digital trims motors can't be instantly stopped or started...however, I will give it a try, see how workable it is in practise.

back on the subject-explain this one? If I mix elev-elev D-30 U-0 when I flick the mix on, up elevator movement is reduced. Ditto, aile-aile, and rudd-rudd-both move less in one direction. Why, then, if I mix thro-thro exactly the same, nothing happens? (I'm experimenting with a servo plugged in to throttle channel, not the esc's) movement of throttle servo does not change when inputting mixing values that affect the other three channels identically

Posted by Timbo - Administrator on 26/10/2009 22:04:47: Posted by Yorkman on 26/10/2009 21:34:45: would be perfectly simple with the old style 'mechanical' trim levers...does anyone think digital trims are an improvement? I certainly don't.  In some ways yes, and others no. Good in so far as they dont get accidentally moved when the Tx is not inuse, but bad for the fact that they can be so slow to operate - nothinhg worse than test flying an unproven model, and quickly realising that it needs abootful of up trim or similar...only to find yourself frustarated by the slowness of the digis to get there!  plus-with mech trims you can 'feel' how far you've moved it..

Posted by Timbo - Administrator on 26/10/2009 21:15:24: Probably via a mix somehow...but why not simply use the throttle trim lever to add a little idle speed, just as in IC, or indeed, simply not close the throtttle stick fully during flying?  That's the simple answer-but not so easy in practise I found this afternoon-the Mossie has so much power that the difference between 'cruise' power (i.e. sustaining level flight) and 'idle'-descent to land in effect-is so small that reducing power to that level is a hit and miss affair to say the least...and then when one motor doesn't start with the other as you ease the throttle open again to keep on the glideslope...oh well, thanks to superglue we have a flyable model again-tho not quite as pretty as it was

would be perfectly simple with the old style 'mechanical' trim levers...does anyone think digital trims are an improvement? I certainly don't.

Is it possible to program my tx via a switch so that in flight the throttle doesn't close completely but keeps the motors spinning (electric)? Obviously needs to be switchable so motors are stopped on the ground. Cheers in advance. Martin

And what I should have said was 'NOT being able to switch it off in flight...' cheers Timbo

which can be overcome by having the mix permanently on and resetting the servo sub-trim....ok...will give that a whirl, better make sure not to overdo it as switching it off midflight could be interesting!

Only trouble with that is, when you switch the mix 'on', up elevator is applied, which returns to neutral as the throttle is opened...

don't see any 'offset' in the mix menu Timbo?

I want to mix throttle and elevator so that as throttle is opened down elevator is fed in....but the tx only wants to mix in the elevator movement after mid throttle position-trying to get elevator movement in the first half of throttle travel results in the elevator going to full 'mixed' deflection at throttle 'closed', then back to neutral at mid-throttle, then moving proportionately to throttle movement over the second part of throttle stick movement. Is there any way of overcoming this? This is my first computer radio. And did I write 'movement' enough times in this post?

Was tongue-in-cheek about using a 1s, don't think I could get CG forward enough for one thing! Smaller props seems like a good idea-she's only on 6x4s now, will have a browse at what's available. Onwards and upwards (slightly less quickly though!)

Further to my thread asking for motor guidance for the GAD Mosquito, she's up and flown her first two flights today. I fitted two of these http://www.giantcod.co.uk/fc2805-1600kv-brushless-outrunner-motor-p-403764.html as recommended by Timbo, with an 1800 mAh 2s lipo (after tests with a 3s smoked the motors!). Model weighs about 16oz (will weigh tonight at work)-did a static thrust test on the table last night against a spring balance- 1 and a quarter pounds! Eeek! Well, put simply, it's ballistic. Flies around perfectly happily on 1/3-1/4 throttle, half throttle and it's a pretty good Saturn 5 impersonation, full? Didn't dare try! Wanted the wings to stay on!!! Perhaps I should try a 1s battery? Certainly kept me on my toes-specially as that's only about the 4th time I've flown anything this year.

Posted by Phil Wood - Moderator on 10/10/2009 02:05:47: It's easy to clock up the number of channels needed if you use a complex system and a top notch model. Add this up........2 servo's for ailerons = 2 channels plus you can add another 2 for flaps or spoilers.......possibly 2 servo's for elevators although you could use a Y lead Add in, Throttle, rudder, retracts, landing lights, bomb bay doors, camera switching, brakes,........I think I've just gone to 13 channels. .....and that's before it makes the tea.   Polyphilla.  Nah-that's cheating, using two channels for one control function! So, 4 basic controls, gear and flaps, ok bomb doors, bomb release, lights, camera, action...brakes...that's 11..more controls than one has fingers! And I struggle to remember which switch gives me takeoff flap...

So I'm going to award myself a gold star as my opening post actually was correct! Even though I had failed completely to do the wattage calculation.......

Having gathered myself again....thanks John for pointing out that I'm looking for 200w per motor-if I run this motor http://www.giantcod.co.uk/black-mantis-bm3650-900kv-inrunner-brushless-motor-p-403926.html through the peakeff program, I'm getting a theoretical 20amp draw @ 10.5v with an APC E 9x7.5-that's got to be close, surely? BTW I hope you're out flying in this glorious sunshine, not stuck inside like me!

Posted by John Cole on 10/10/2009 11:37:50: I'm not sure but I THINK you mean you want 400 W total, for your twin (4 lbs @ 100 Watts per lb) : that is 200 W per motor ?   that's both Timbo and I missing the obvious-well spotted John!

What on earth does anyone need 12-count 'em-12 channels for???

Just a quickie-tho not relevant to a Spit if you're being 'true' as real ones only had 2 position flaps-up or down- you can 'mix' the flap channel on the Dx6i to give 3 positions (I have), so the York has 'up','takeoff' and 'landing'. Cheers