Propping a Z11..

[M6TPV]

I've built my Z11 a little on the heavy side, on my fishing scales she's 3.3kg fully loaded and balanced.

Plan was to use a 9x6 Prop but wondering if there would be any benefit in using a 10x5 which is theoretically the same but I don't  know what he benefits of theoretical sizing has on a Z11.

I am running a ritewing 1200kw motor with 4S batteries and a Talon 90Amp ESC...

Cheers,


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[pk-surfing]

I've got a 10x6 on mine but that's with a Hacker on 4S

Maybe fit a 10x6 and do a static full throttle test with a Watt meter installed and see if the motor is happy without drawing more amps than it's rated at ?

PK

[M6TPV]

Out of interest, What's the weight of your Z11 ?

A 10x6 may be an idea.. I am just concerned I've built my Zed too heavy and I'll need increased thrust to get her airborne...


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[pk-surfing]

Hi,

Just weighed it,

1820 g without lipos
2440 g with two 4S 3300 Turnigy lipos fitted ready to fly

The motor is a Hacker A30 8XL

I have a dummy lead weight of 96g in the GoPro bay (take it out when GP fitted) but also another 120g of lead under the front to get the C of G right.

Using the overhead single hand on the front launch (as per Ritewing) on full throttle it goes off nicely with a 45 degree launch

What kit have you on yours that's adding the weight (bigger lipo's) ?

PK

[M6TPV]

I've got 3700 batteries and an FY-Dos + GPS.  The ESC is a big beast too which I guess is adding to the weight factor.  I've also lam'd and then covered her in oracover..  Having said that the fishing scales look like something out of a Christmas cracker so she maybe lighter, or heavier :-/

Mines not yet been airborne, was hoping to maiden today but the wind was completely in the wrong direction.

Maybe next time I build one she'll be lighter...




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[pk-surfing]

Its going to be fine at that weight, just done hold back on the launch.

It needs full throttle and a good full shove (or will it be a pull from the front  :) ?) up at a reasonable angle.... definitely not a wussy launch out level in front.

Main drawback of that very first flight is not knowing where 'neutral' trim is on the elevons !

It's alright me saying don't forget to put in about 3 to 6 clicks of up trim in on the transmitter for launch (it works for me) but that's assuming 'no clicks' of elevator trim is your healthy level flight trim.

Some up trim for launch just makes sure the nose is going to keep up.

Also check how it balances laterally, I had to put a bit of lead cut into a slot on the left wing to get my lateral balance ok.

PK

[M6TPV]

I've followed the CoG vid on YouTube that Chris Klick did and have it 3.5inch from motor firewall. Elevons have about 2mm up trim on them as also described by Chris.  Anymore or any less will only become evident after launch.

Earlier today my mate and I had her out front, he held her nose up, hands either side the GoPro case and we turned on full throttle.. She appeared to just about able to hold herself in same place if not give a little bit up as he loosened his grip..

Good idea to check lateral trim too, with my fingers on the CoG points she is ever so slightly nose heavy but seems to be fine laterally.. It's one to check tomorrow though.

I do like the overhead launch which I do on my Zagi, but then she's half the size and a quarter the weight... I've not invested in a catapult... I may have to, but we'll wait and see as its all about flying, not building at the field.

Cheers



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[pk-surfing]

Looking forward to hearing how it goes, just give it full throttle and don't hold back on giving it a good fling and follow through....

I won't wish good luck cos you won't need it, they fly sooo nice (once in the air hehe)  :)

PK

[M6TPV]

I will report back as soon as its all been successful... I will ensure I take some before and after pics and of course video.

Out of interest, what RC Control are you using?  I was hoping to use EzUHF but having a right royal nightmare with it.  I have had to resort to 35 Megs as use 2.4 for video.


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[pk-surfing]

EzUHF should be sweet so not good that you're having problems with it, better than 35mhz by a long way (but not if it's causing problems  :) )

I'm using UHF on most of my planes but do have FrSky fitted to some quads/tri.

PK

[DaveyLC]

Yeah I'd be interested in hearing about your EzUHF issues too?

[M6TPV]

Yeah I'd be interested in hearing about your EzUHF issues too?

I was hoping for a sweet transition but sadly I first got one receiver that was of the non QC batch that needed recalling. 

The replacement receiver, well, it was in the Zed and my friend and I were setting up the throws on the elevons and were half way through and nothing gut and awful smell of burnt vero-board from the Rxer and the Flashing LED was on solid.  Can't connect to IRC Tools and can't rebind. 

Put in a 2.4 futaba 617 Rx'er, completed setting up,the elevons... No issues at all.  Put in a 35Meg Rx'er, works fine...

Can't understand what's happened to the EzUHF Rx'er and why it would fry..especially if other Rx'ers are working.



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[DaveyLC]

Wire plugged in wrong? The lack of plastic body makes it so easy to accidentally plug in to just two pins so you can end up reversing the polarity or putting 5v up the signal pin :(

Did you check the rx for a burnt out RP Diode or surface Fuse?

[Flyn]

My mates did the same, was plugged correctly & working & just fried on the bench :(

[M6TPV]

Wire plugged in wrong? The lack of plastic body makes it so easy to accidentally plug in to just two pins so you can end up reversing the polarity or putting 5v up the signal pin :(

Did you check the rx for a burnt out RP Diode or surface Fuse?

It was wired up ok, I was very conscious of making a silly mistake I checked several times... And as all the leads except one only carry signal it's even harder to get them mis-orientated.  I have an FY-DOS for RTH and stabilisation in there.. We checked the voltage was 5.79 and have been assured that the Rx'er can accept as much as 7.4 without issue.  On closer inspection its the top board that has the SMA antenna and new tin shield that smells of something burnt...

As Flynn says, I'm not the only one whose suffered this issue, I'm praying to god that Firstpersonview will resolve it otherwise its £100 gone, on the bright side of things, at least the Zed wasn't 400ft up and half a mile out otherwise it would have been nearer £1000 gone west, east, south and probably north as well.

Plan for the future is to soak test on a simplified airframe and fly that with EzUHF until my confidence levels return to normal levels...


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