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Old Mar 22, 2012, 05:51 AM
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Australia, QLD, Ipswich
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Quote:
Originally Posted by Finnspeed View Post
I have my Bandit (almost) ready for maiden flight now. All I have to do is to balance the prop and wait for the 1/2 meter of snow to melt from the local field...

In the mean time, a couple of questions I'm sure someone can answer:
- what's the weight of the carbon spinner for Bandit?
- whats the weight of the Quantum 45 ESC?

While everyone else has to place the 3S battery half way into the motor box, my Bandit seems to balance only if I pull it back about an inch from the firewall. I deliberately was cautious to keep the tail light and did not worry about slightly heavier motor, ESC, prop and spinner. Now it looks like I may want to reduce some weight from the nose...

Well, I was going to use an aluminum spinner that weighs 21 grams. Also the APC E 13 x 16.5 prop is about 10 g heavier than the wooden VOX and finally the Turnigy Plush 60 ESC is probably much heavier than the Quantum. Knowing the weights of the PA parts would help in deciding what to do. Clearly it is very easy to leave the spinner out and use the VOX which would reduce nose weight by some 30 g.

Lesson learned: The Bandit airframe is so light without any equipment that relatively small changes in equipment weight easily moves the CG point by several centimeters.
How heavy is your motor?

I use a Plush 60, motrolfly 2820 which is maybe 10g heavier than the PA motor. I also use a differnet carbon spinner which is probably 20-30g and also use an APC 13x6.5, my motor box is also heavily coated with epoxy in places. I still need the batrery through the firewall a bit so I'm surprised your so nose heavy, unless that motor of yours is a real heavyweight.
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Old Mar 22, 2012, 12:02 PM
F3A Team Finland
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Järvenpää, Finland
Joined Nov 2005
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@Luke352: Thanks for the reply! I'm using NTM Prop Drive 35-42 1000kv which weighs 147 g. So that makes is pretty close to what you are using. Also the prop, spinner and ESC are the same weight then. What's your complete AUW with 3S battery? Mine is 1280 g which is heavier than what PA estimates but not by much.

I have also added some weight to the motor box by wrapping a thin carbon fiber tow around the motor mount plate and adding some epoxy here and there but the weight increase by that was only 3 g. Then after that I added a cut cross mount from the NTM accessory kit to the motor mount plate to make sure the plate is not weakened by the two additional screw holes required to mount the NTM motor. That is some 4-5 g of additional weight.

Based on that, my Bandit should not be much different from yours but it is. I did mount the Plush 60 ESC as forward as I could without adding servo extensions to it and my RX is in the standard position. I had to add 2" extensions to the battery wires though. Another difference could be the tail where I have the BMS versions of the Voltec servos and lightweight extensions to connect them to the RX.

Well, in any case I will post some photos later to show where my equipment are. I might also add that my Bandit must be from 2nd production run since the triangle reinforcements in the motor box were already trimmed to fit the motor right in. I wonder if there are other subtle changes to move the CG a bit further forward, mainly to avoid a too difficult battery position?

***Risto***
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Last edited by Finnspeed; Mar 22, 2012 at 04:38 PM. Reason: Added pics
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Old Mar 22, 2012, 07:09 PM
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Hmmm, I can't see why your having the nose heavy issue. That xmount has probably added a bit of weight right out front but I can't it being enough to cause issues with balancing.

TBH I don't know my AUW as i've never weighed it, but mine would be heavier as i'm flying with 4s. I also have Blue Bird/BMS 375DMG servo's which i'm guessing is similar to what you have.

It's a bit perplexing really, maybe yours just came from the factory very tail light.
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Old Mar 22, 2012, 07:27 PM
Bass Cannon kick it! "WUB WUB"
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Australia, NSW, Sutherland
Joined Dec 2010
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Hahaha I like mine nose heavy.

I actually fly mine with the PA 3S 2200 half in the motor box but then I also have (I think) about 30 grams of weight in the cowl. Balances out at around the first hole in the underside of the wing.

Pretty sure mine is a V1,
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Old Mar 23, 2012, 03:24 AM
F3A Team Finland
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Järvenpää, Finland
Joined Nov 2005
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Quote:
Originally Posted by luke352 View Post
Hmmm, I can't see why your having the nose heavy issue. That xmount has probably added a bit of weight right out front but I can't it being enough to cause issues with balancing.

TBH I don't know my AUW as i've never weighed it, but mine would be heavier as i'm flying with 4s. I also have Blue Bird/BMS 375DMG servo's which i'm guessing is similar to what you have.

It's a bit perplexing really, maybe yours just came from the factory very tail light.
That's what I'm thinking too, it must have been tail light from the factory. My servos are the analog variant BMS-373MG which are exactly the same weight so that doesn't explain the difference either. Light vs. standard servo wire extensions do make some difference which could be 2-3 g per servo though.

OK, I'm going to experiment a bit with the prop and spinner to see how much they affect the CG. I still have (too much) time to do that before the snow is gone...
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Old Mar 23, 2012, 07:58 AM
Grumpy old git.. Who me?
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Aberdeen
Joined Mar 2006
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Finnspeed,

I think your nose heaviness is a result of lots of small things adding up, nothing to do with the tail being especially light:

Reincorcing of motor box: approx 10g
Heavier motor: 7g
Hobbywing ESC (these are really heavy, close to 60g): 25g
Spinner: 5g
Prop 5g

Before you know it you have 50g of extra weight in the nose which will mean the battery has to go way back.

Single biggest change i think would be the ESC. ZTW/Black Mantis/Mystery (all the same thing) do cheap and lightweight ESC's that perform great.
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Old Mar 23, 2012, 08:22 PM
Pilot Francis 😄
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United Kingdom, England, Brighton
Joined Jan 2012
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Damn I miss this plane, I really need to repair it! I'm thinking of simply buying just another frame, but this time orange! Also gonna try the Thunder Power 45C 4S batteries because they look great! Are EC3 connectors ok for this? Thanks!
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Old Mar 24, 2012, 04:40 AM
nerd
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Linköping, Sweden
Joined Jul 2007
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Finally winter is over and I got a chance to maiden my Bandit yesterday. Been waiting all winter for this.

But I found an issue with the Thrust40 / Quantum 45Pro ESC. When on full power it suddenly drops RPM for a while and then back up to full again. And then it keeps pulsing like that. Sounds as if it was shifting gears....
I did try a few different LiPos fresh from the charger, and did set LVC to low. No difference.
Anyone else had this strange behaviour?
I tested only with 3S2200 and a 14x7 Vox. Maybe I should have tried 4S and 12x6 also....
But now I have replaced the Qauntum with Tgy K-force 40A will try it later today..
/A
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Old Mar 24, 2012, 05:19 AM
Pilot Francis 😄
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United Kingdom, England, Brighton
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Hi everyone, what do you think of these as a servo choice? http://www.mks-servo.co.uk/mks-micro...wband-18-p.asp

Also, is 45C Thunder Power too much for the Bandit?
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Last edited by RCPilot1234; Mar 24, 2012 at 06:24 AM.
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Old Mar 24, 2012, 05:20 AM
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Australia, ACT, Kambah
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Cold/weak batteries just not able to stay even below your lowest LVC setting could be the cause
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Old Mar 24, 2012, 06:01 AM
Precision Aerobatics Team
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South Africa, GP, Randburg
Joined Dec 2006
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Quote:
Originally Posted by AndWho View Post
Finally winter is over and I got a chance to maiden my Bandit yesterday. Been waiting all winter for this.

But I found an issue with the Thrust40 / Quantum 45Pro ESC. When on full power it suddenly drops RPM for a while and then back up to full again. And then it keeps pulsing like that. Sounds as if it was shifting gears....
I did try a few different LiPos fresh from the charger, and did set LVC to low. No difference.
Anyone else had this strange behaviour?
I tested only with 3S2200 and a 14x7 Vox. Maybe I should have tried 4S and 12x6 also....
But now I have replaced the Qauntum with Tgy K-force 40A will try it later today..
/A
I have experienced the exact same thing. It is definitely your lipos that are not up to the task.
What 3S 2200's are you using and how old are they?
Have you been storing them at 3.8v/cell over the winter?
I have some old 30C Zippy's that do the same thing. I'm going to donate them to an old timer at our club for his 20 000 ft high wing Sunday cruiser that only needs 10A to fly
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Old Mar 24, 2012, 10:03 PM
OOPS
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USA, GA, Cochran
Joined Jun 2008
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Chris Scoggins and the Bandit (5 min 1 sec)


Finally got to hook up with my bro Chris for some afternoon flying.He even let me get a pull on it after this flight..The wind was stupid gusty.Must be time for SEFF.lol
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Old Mar 25, 2012, 01:24 AM
Bass Cannon kick it! "WUB WUB"
cloaked's Avatar
Australia, NSW, Sutherland
Joined Dec 2010
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Pre Game: 7 Batteries Charged
Aftermath: 7 Batteries (still) Charged.


Outcome: Footballers showed up before I even tightened the wing nuts

2 weeks without a Bandit flight!
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Old Mar 25, 2012, 05:45 AM
Pilot Francis 😄
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United Kingdom, England, Brighton
Joined Jan 2012
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Because I'm rebuilding the Bandit, I thought I might as well get new servos I wanted to try something different from the Hitec's.

Do you think these are a suitable alternative? http://www.airtronics.net/index.php/...-mg-servo.html

Thanks!
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Old Mar 25, 2012, 07:02 AM
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Should be very nice servo's! Thing about Hitec's is they are typically reliable well priced servo's, but typically don't centre well and can be a bit current heavy.
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