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Q & A Thread For Newbies & Old Hands Alike!
#1

Hi Kieren
Quick Question Regarding Brake or no brake

Currently my esc is factory default no brake, on Fun jet,
Do you recommend prop brake , advantages / disadvantages
Whats your Stryker set at.

Steve

What Do You Mean Theres a Throttle Curve ?, Its Either all the way up or all the way down Tongue_smile
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#2

Basically determines how much drag you'd like on the aircraft. Having the brake off will allow the prop disc to free wheel and slow down the plane quite quickly, even in a dive. The prop brake on will remove this drag and allow you to do things like power off terminal velocity dives and 29 minute gliding flights!

Like everything, comes down to personal taste but of late I prefer the prop brake on for my stryker, the only caveat is you have to get used to a long glide before landing which makes things tricky if you like planting the thing at your feet Wink
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#3

Thanks for that Kieren i may leave the prop brake off till i get a few more hours of experience on the fun jet. Smile

What Do You Mean Theres a Throttle Curve ?, Its Either all the way up or all the way down Tongue_smile
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#4

Steve, what motor and esc are you using in the funjet?
Kieran, what are you planning to put in yours?

Paul

Jet Teng L39(Breitling)
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Vector X
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#5

Haven't decided yet but probably something stupid Wink

Probably initially it will be the motor off the Stryker that went walkabout.
2200Kv seems to be the sweet spot for performance vs weight so I may stick to that but go for a 40 or 60 amp Speedy to allow me a large choice of props
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#6

paulj Wrote:Steve, what motor and esc are you using in the funjet?
Paul

I'm Running at moment stryker Motor,60 amp venom ESC and 7x5 APC prop seems to work well and a lot faster
than the original 6x4 stryker prop.

Heres a two links That you might want to look at in Regards to Motors for Funjet as these are what people are talking on online forums about using in the USA in replacement of stryker motor better performance they say.
I have ordered one of each as i have no replacement as yet if stryker motor fails,
Hopefully they are as good as the spec reads Smile, not sure though what prop they are using ?
I assume they are sticking to std stryker 6x4 prop, though the hobbyking item reviews i noticed say differently.
http://www.hobbyking.com/hobbyking/store...oduct=5221
http://www.hobbyking.com/hobbyking/store...oduct=5222

What Do You Mean Theres a Throttle Curve ?, Its Either all the way up or all the way down Tongue_smile
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#7

Thanks for those links.
I read in some forum that 28mm dia was the largest size that will
fit on the funjet mount, so these should be ok.
If we wanted a bigger size do you reckon it would be very hard to change to some other
mount?

Paul

Jet Teng L39(Breitling)
Scratchbuilt F14 Tomcat(Pukin Dogs)
Vector X
Eflite F86 Sabre(Taz Tiger)
Qantas Airbus A380(Nancy-Bird Walton)
Boeing 737-800
ProEDF F16
Falcon 120(Gas Turbine)
Fly Fly F100 Super Sabre
Pheonix Tiger 6
VQ Models P61 Night Fighter
CY Models FW190

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#8

paulj Wrote:If we wanted a bigger size do you reckon it would be very hard to change to some other
mount?
Paul

I cannot see why not there is plenty of room and its flat where the motor mount is.

With my motor mount i have custom ed the fixing with a bolt straight through the rear body to the underside and used a carbon plank as a big washer as well i re-glued mount with plenty of glue.
As the mount is glued only at the rear and i was concerned that it may give way.
As the prop hits the ground when landing and it may or may not add stress to motor mount, especially I'm running ESC without prop brake on. (Probably an overkill though)
Though i did read in a forum that some one's Funjet motor mount came off in flight on first flight, it may have not been glued down well or glued at all.

What Do You Mean Theres a Throttle Curve ?, Its Either all the way up or all the way down Tongue_smile
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#9

Yea I read that somewhere too.
Had another fly of Kieran's striker today and really enjoyed it..
Can't wait to get the funjets

Paul

Jet Teng L39(Breitling)
Scratchbuilt F14 Tomcat(Pukin Dogs)
Vector X
Eflite F86 Sabre(Taz Tiger)
Qantas Airbus A380(Nancy-Bird Walton)
Boeing 737-800
ProEDF F16
Falcon 120(Gas Turbine)
Fly Fly F100 Super Sabre
Pheonix Tiger 6
VQ Models P61 Night Fighter
CY Models FW190

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#10

i couldnt believe how well the stryker flew also , i cant wait to see if the funjet has the same characteristics, you can glide forever with that stryker Smile

Jet Teng BAE Hawk 2010 Demo Team
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#11

Looking at buying hobbyking order

http://www.hobbyking.com/hobbyking/store...oduct=9612

or this expensive polyquest
http://www.hobbyking.com/hobbyking/store...oduct=5584

To run in The A-10 as i am thinking i need something that can cope with 75 amp max bursts and probably about
30 - 40 amps continuous.

Unless i go to batteries in parrallel ?

I ran on Maiden 2200ma turnigy 30c-40c, seem to be ok.

What Do You Mean Theres a Throttle Curve ?, Its Either all the way up or all the way down Tongue_smile
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#12

How about this one, should give a slightly longer flight:
http://www.hobbyking.com/hobbyking/stor ... oduct=9497

I wouldn't bother with the Polyquest, batteries should be treated as consumables in planes Wink
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#13

lol kierens avatar.. Lol

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#14

samste Wrote:or this expensive polyquest

yeah i had looked at those b4 and wondered just what difference they would make... :roll:

Jet Teng BAE Hawk 2010 Demo Team
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ESM Texan II / 35cc Gasser
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#15

hey just wondering if anyone has ever mixed in any rudder with aielerons? and if so what affect would this give? perhaps a faster roll rate? say like 10% rudder or something :?:

Jet Teng BAE Hawk 2010 Demo Team
Sapac Blue Arrows Hawk
ESM Texan II / 35cc Gasser
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#16

Gday Kev

I have aileron to rudder mix set up on all my aircraft, I use this to stop adverse yaw and keep the aircraft balanced in the initial part of a turn, I also use differential aileron, once again, to prevent adverse yaw. It does not increase roll rate as far as I can tell however it will give the aircraft a tendency to nose down in the turn so a good positive pull back on the elevators is needed to keep the nose up and the turn level. I still use the rudder independantly to balance turns at higher angles of bank. If you want a nice smooth roll you may not wish to use this as your rolls will become axial, ie more like a loaded victory roll

Cheers
Rob B
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#17

hey good response rob, i think ill try some experimenting with actual flying when i get back in the air rather than colliding Lol

Jet Teng BAE Hawk 2010 Demo Team
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ESM Texan II / 35cc Gasser
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#18

Gday Kev

As an addition to my earlier comment you would slightly increase the roll rate using rudder however this would be via the yaw component. Note that you can use your tx switches to turn ail/ rud mix on and off in flight. This is handy when setting up the % and also good if you want some nice crisp yaw free rolls. I'd be happy to run you through this down at the field.

Cheers
Rob B
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#19

yeah rob that would be great mate.. of course i will have to wait until i get her new enigine bolted in.. else perhaps i could get the t28 towed up to say 400ft and trim her out , though i think she would be a touch tail heavy.

Jet Teng BAE Hawk 2010 Demo Team
Sapac Blue Arrows Hawk
ESM Texan II / 35cc Gasser
PRO-EDF Composite F16
HK 450 Heli
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#20

Hi,

My Easystar is ready for its first flight this weekend but I'm worried about the length of the leads from the esc to the brushless motor. Its a pusher and the leads are about 300mm long. Does anybody know of any issues that may crop up with long leads.

Thanks
Servo
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#21

I cannot see an issue as long as the cables between the motor and esc are big enough to cope with the amps, i would probably want the cables at least the same size as the esc wires if not bigger. as i cannot see voltage drop a major issue but heat generated from the amps flowing could be an issue and motor wires melting.( though that would be an extreme case scenario)
My A-10 has quite a distance 15cm from each motor to esc, i used a slightly thicker gauge wire just in case and it seems to be OK.
The same applied from battery to esc, i used a double + thickness gauge wire as its feeding two esc's and distance to front is 40cm

Steve

What Do You Mean Theres a Throttle Curve ?, Its Either all the way up or all the way down Tongue_smile
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#22

Servo Wrote:Hi,
My Easystar is ready for its first flight this weekend
Thanks
Servo

Hey Kev look forward to seeing you up in the air mate!

Jet Teng BAE Hawk 2010 Demo Team
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#23

Servo-Kev,
Have you put a wattmeter/ammeter on the setup and maxed out the throttle? You could do that for a couple of minutes look at the amperage and then see if the wiring is cold/warm/hot. Might help to get an idea.
See you soon,
Steve

P.S. Sorry I couldn't take your call today, I was in the library looking for books on aerodynamics so I could find out a bit about the adverse-yaw characteristic that I've got to iron out of my trainer. I would have liked to see your big-screen test!

Steve Murray
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#24

Gday Steve

What specifically are you trying to find out about adverse yaw, I will be able to easily assist you with this.
However, in a nutshell, it is caused by the fact that during a turn one aileron is deflected up and thus in a low pressure area and the other is deflected down and therefore in a high pressure area, as more drag is produced in the high pressure area it thus slows that wing down causing the aircraft to yaw in the opposite direction of the turn. There are 2 ways to combat this, either by differential (or Frise) ailerons, or, by positive and coordinated use of the rudder, or, a combo of the 2.

Cheers
Rob B
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#25

robair Wrote:Gday Steve

What specifically are you trying to find out about adverse yaw, I will be able to easily assist you with this.
However, in a nutshell, it is caused by the fact that during a turn one aileron is deflected up and thus in a low pressure area and the other is deflected down and therefore in a high pressure area, as more drag is produced in the high pressure area it thus slows that wing down causing the aircraft to yaw in the opposite direction of the turn. There are 2 ways to combat this, either by differential (or Frise) ailerons, or, by positive and coordinated use of the rudder, or, a combo of the 2.

Cheers
Rob B

The force is strong in this one :ugeek:

Clearly i have a lot to learn about flying :!: . i for tho most part push the throttle flat and pull back Lol
i have to learn to use the rudder as mostly i dont even use that axis of control at all.. i do all my correcting and what not by banking the plane and adding various amounts of elevator input..

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#26

Nothing wrong with yanking and banking!

Steve just needs to separate his aileron servo's and then we'll be able to work some differential into the setup and stop the thing swaying on a pole Smile
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#27

Thanks for the replys, been busy at work and did't have time to reply.

re the wire size the wire gauge out of the esc (30amp) is much larger than the wire size that comes as part of the motor so I guess I will try a size inbetween.

I was thinking of getting a clamp type amp meter but had a question, the current out of the esc is chopped at high frequecy and I was wondering if the cheaper amp meters gave accurate reading at these frequencys. I guess just reading the input current to the esc should not be a problem and as informative.

As I understand it the esc looks for little voltage spikes on the leads into the motor inorder to decide when to switch each winding and I'm affraid the extra resistance in the longer leads may not allow the spikes to form properly.

Pity you missed the big screen Steve, I'v just installed a data projector into a research lab, the screen is 2000mm high and 2600mm wide (that a 328cm dia) so I took in my laptop and ran the Great planes simulator on it. The bottom of the screen is at floor level and you stand 2.5 meters from it.
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#28

thats a great idea kev. I was running realflight g4 from a laptop onto a 100 inch screen at home initially.its how i became comfortable with mode 1 orientation!

Jet Teng BAE Hawk 2010 Demo Team
Sapac Blue Arrows Hawk
ESM Texan II / 35cc Gasser
PRO-EDF Composite F16
HK 450 Heli
Seagull PC-9
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Falcon 120 (Prepping for Kingtech K100 turbine )
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#29

Rob - thanks for the input on my adverse-yaw problem, much appreciated. The mixed-in rudder solution was one that occurred to me but I've not heard of Frise ailerons - that's interesting! I'd like to talk this over with you tomorrow if you're going to be at the field, interesting stuff. I've been trying to find out whether the aileron throws need tweaking, whether too much dihedral in the wing is a contributer, whether the aileron placement on the wing is a factor (they're mainly out towards the tips) and/or if the aerofoil has something to do with it. Lots of variables ... and a reminder that when you scratch the surface, flight dynamics is a complicated business Smile
See you tomorrow!
Steve

Steve Murray
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#30

Gday Steve

The trick here is not to overcomplicate the matter. Your aileron throws should be exactly the same length, dihedral is not an issue, that merely makes the aircraft more stable around the lateral axis, the location of the ailerons is also not a major factor nor the airfoil shape. The size (surface area) of the ailerons is the trigger, the bigger the ailerons the larger your adverse yaw will be. The amount of deflection of the surface will also need to be considered, once again the larger the deflection the greater the yaw.
When I was learning to fly I was initially not very positive with the rudder much to the dismay of my instructor and the balance ball. To cure this I went out to Camden and flew gliders, due to the fact that they have huge non differential ailerons the adverse yaw is massive and coordinated rudder use is critical. The Blanik that I flew would deflect 10 to 15 odd degress in adverse yaw if you ignored the rudder. I would get bopped on the back of my head by my instructor with an ERSA every time I got it wrong. Once I had mastered this on the gliders I never looked back.

Cheers
Rob B
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