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Old Apr 06, 2015, 08:51 AM
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oh yeah 2200kV on 4S is gonna go like hell allright!
I run Turnigy 2826 2200kVers on my little X-Wing, Radjet and WingWing with either 6x4 or 6x5.5 APC props, but on 3S and they scoot. And scream... noisy little buggers.

Checked the cell voltages on the Zippy Compacts that came last week and found one battery has a low cell: 3.77 vs 3.86 on the other three.
Have sent a return request to HK asking them to send me a new one (they promptly did this last year for a 4000mAh Zippy with a low cell), but what's everyone's opinion: could it still be good?
I'd have to change the plug to an XT-90 to balance charge it, and before I do so wanted to give HK notice.
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Old Apr 08, 2015, 04:04 PM
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Well since I'm wait for HK to decided if they want to send my order I ordered a week ago, I decided to shelf the 71 and work on a 16 until my order comes in. I did receive the HK after burner kit that was ordered after the other order and from the east cost warehouse, SO I decided to pull her back down and fit for the After burner light kit. I have been debating on doing a Rudder mod or not. So today a lunch I went home and busted out one of the rudder mods. It actually went smoother than I planed.

I'm doing a full rudder control. First I cut the rudder into two section bottom and top at the horizontal line on the rudder. So what I did was use a small OD carbon fiber rod into the top section of the rudder. I put a carbon fiber rod that the other one fits into in the bottom section of the rudder. I will put a control horn on the small OD at the seam between upper and lower rudder sections. I then cut the servo into the bottom section, I will cover with thin styrene. the wire will go through the nacelle and into the back fuse section to the rx.
Looks like it will work perfectly. I will post pics after I get the first one done and the second one started so I can illustrate exactly what I did.

Here is the light kit. I cut the burner section into two pieces which ends up being a perfect fit for both sides.
SR-71 after-burner light kit from Hobby King. (0 min 56 sec)


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Gravy
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Old Apr 08, 2015, 10:05 PM
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Here is my rudder mod.
My SR-71 rudder mod (1 min 25 sec)


Thanks
Gravy
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Old Apr 08, 2015, 11:54 PM
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cool mods Gravy!

Is this the LED kit you used?
http://www.hobbyking.com/hobbyking/s..._70mm_EDF.html

Looks like yours includes other LEDs besides the afterburners though?
Could you please post a couple pics of how you mounted the LEDs in the tailcone?

I'm going lean and mean for at least the first few flights on mine, but after that may add some "bling"
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Old Apr 09, 2015, 08:52 AM
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http://www.hobbyking.com/hobbyking/s...ng_System.htmlNope this is the kit i got.

Haven't installed it yet. I'll post pics when I do though

Gravy
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Old Apr 09, 2015, 10:23 AM
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Nice! I like how you did the full moving scale rudder, not the seamline rudder aft like for most craft.
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Old Apr 09, 2015, 10:32 AM
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Does look good, the only thing I'd be worry about is the forces on the z-bent control link. Once that baby is cruising at speed there's going to be a lot of force on it, and once the stab turns a little bit in either direction aerodynamic forces will want to keep twisting it out or in (unless you calculated where the pivot is to be the exact center of pressure?) I'd think you'll need a pretty beefy servo and robust link to keep them where you want them.
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Old Apr 09, 2015, 10:48 AM
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Thanks guys. I'm using metal gear servos with a Stall torque of 1.6/2.0 kg.cm 21.0/28.0 oz.in (4.8V/6v). These little servos have a good punch. I have been using them for a while now. I have learned to disconnect all linkages before I power them up for my initial setup. I did that once while still hooked up to my control surface and the servo torqued and ripped the horn right off with foam still attached.
I am going to change the linkage setup. I'm going to use screw tight connectors on both horns and get rid of the clip on. That should firm it up and make a much better solid connection. I also think that a little rudder will go a long way and only really think I may use it to punch out of a death spin, Which I prey never happens.

Gravy
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Old Apr 09, 2015, 10:53 AM
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I've used rudder in a couple of my past Blackbirds (RIP) and I personally don't mind the yank and bank method of sans rudder. It is nice to have some rudder to smooth out those turns and make them more coordinated but I agree very little rudder input is needed or very, very bad things could happen in a flash.
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Old Apr 09, 2015, 11:09 AM
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From what I have seen and read I'm thinking of using lots of expo on my rudder, like 75%. That way I get very little rudder movement until I get to the extreme stick left or right position. I can see using little for a nice coordinated turn as you state, but IF i get into a flat spin I think lots of rudder will help me punch out of it. From what I have seen Ailerons and throttle are not enough to get out of the death spin.

Gravy.
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Old Apr 09, 2015, 11:20 AM
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Yep that's a good point. High expo so you have it when you need it. Rudder indeed "might" get you out of the dreaded "Habu Hellspin".
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