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Jul 31, 2013, 12:19 AM
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Discussion

RCRCM Sunbird E 60"


We this is not going to be a build thread but more of a build help.
I have buit a few planes and gliders but usually with some decent direction.
The few directions I can find are very vague and basically just give you a hint on what to do. The kit I got does not have the servo horns attached to the surfaces like I think these came before. This is one of the areas I am having a hard time with.
1. At this point I have the wiring harnesses in the wing and glued into place.
2. I have the ruder and elevator servos installed. (I needed the wood because my servos were hitting the other side of the fuselage.
3. I have the elevator rod installed. (that was not to bad to do and is working nicely).

The wing servo install is giving me a hard time.
Can someone explain how to install the horns on the control surfaces and how the control rods get from the underside of the wing to the horn on the top side. (do you have to drill a hole)?

Anyway I will post a few photos along the way.

Any photos you guys have or input to help out would be great. This is my 1st molded model.
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Aug 03, 2013, 01:32 PM
Registered User
I just finished building an electric Sunbird. I was surprised to not find any references to the electric Sunbird anywhere online. I used the Sunbird slope thread for anything related to the wing and control throws, and for the fuselage I found that the electric Typhoon thread was useful.

I set up the tail servos a little differently from the way you're doing it. I used a shorter servo horn on the elevator servo, and I ran the rudder control horn just below it on the same side. They come close to each other, but they never touch.

For the wing servos, yes, you do have to drill out quite a bit of the spar between the servo pocket and the control surface. I think there are pictures in the Sunbird slope thread showing how to do that.

For the control horns on all surfaces, I ran a 6" control rod through the hole in the control horn, then taped the control rod along the ridge where the control surface and the wiper meet. This put the control horn in exactly the location in needs to be in to glue it in place. You will also have to drill out the inside of the control surface a bit to get the control horns to fit in place inside the control surface. Be careful doing this part or you might drill through the control surface outer skin.
Aug 05, 2013, 07:19 PM
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ecenshu's Avatar
GeraldC, would you mind sharing your power setup? I had been looking at this option but was never sure of what would be an appropriate setup. The Sunbird-E really is lacking info online.
Aug 05, 2013, 10:44 PM
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Thread OP
Well I finished my bird. It comes in at 40oz. I figured everything out once I dove into building it. I think it took about 8 hours max.

Does anyone know what CG works well?

I will post some photo's
Last edited by ugottofly; Aug 05, 2013 at 11:10 PM.
Aug 05, 2013, 11:21 PM
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Thread OP

photo


Under the
Aug 06, 2013, 06:34 PM
Registered User
There's quite a bit of CG discussion on the slope thread:

https://www.rcgroups.com/forums/show....php?t=1004366

I believe the manual says something like 69mm for a starting point, but that's way too far forward. I'm at 74mm after my first few flights and I can tell I'm going to be pushing it back a little bit from there as I get more familiar with the plane.

Ecenshu, I'm running a Neu 1105/2.5y/4.4 with 3-cell 2200 batteries. With that motor, the battery has to sit way under the wing to get it to balance at 74mm. Without the battery, I believe it was a bit nose heavy, and the battery ends up behind the CG to make things balance. I'd like to push the CG back a bit more, but I'll have to tweak things a bit to push the battery back any further under the wing.

I'm currently running a 12x10 prop while I get used to the plane. I could run something bigger, but I'm really in no hurry to switch props as performance with the current setup is good enough for me for now.
Aug 07, 2013, 08:56 AM
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320pilot's Avatar
The Neu 1105/2.5Y/4.4 motor is a jewel. I fly it with an RFM 13 X 9 prop on my BulleT. I just put in a new TP 3S-2250-70 C LiPo.

With this prop the motor pulls 54 Amps 504 Watts . Motor is on a switch.
Last edited by 320pilot; Aug 07, 2013 at 12:27 PM.
Aug 13, 2013, 11:26 AM
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Thread OP
Well I have flew my Sunbird a few times getting ready to bring it to Hawaii tomorrow. I flew it off a small slope with light wind for 20min with just a little power on and off. The 1300 battery was only used up about 1/2.

I was working on setting up my crow for some slow landings. Its amazing that it almost comes to a hover with full crow and a little power. I think I am going to set up about 1/2 crow and full crow today and test that out.

Also my CG is about 75mm back from LE. I need to try it back and forward to find the sweet spot.

Overall I am happy with the model.

This was the slope. It is a double tear building site in Irvine.
Dec 05, 2013, 02:16 AM
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leebee1965's Avatar
I'm thinking of getting one of these planes, what's the verdict? Are they any good?
Dec 19, 2013, 07:49 AM
Registered User
Hello! I`m interesting in fast motorized glider hotliner or f5b style glider for aerobatics and hight speed low passes, not for competitions, also not for slopes (we havent got powerfull slopes in Saint-Petersburg).
What is you feeling what is more apropriate for this - Electric Sunbird, or famous V-MAX (plane with many names Wilco Hawk F5B).
Mar 15, 2014, 05:45 PM
Registered User

Did Olerc send me wrong fuselage?


I just got my Carbon Fiber Sunbird from Olerc. I DO NOT see the servo bay opening behind the wing. I do not have a slot for the elevator and rudder servo.

Look like they send me a slope fuselage with the nose cut away. Is this normal?

Now my sunbird is very nose heavy.I am trying to get my CG at 77mm. I have to add 2oz lead by the tail to balance 1350 battery and 3oz for 2200. This is crazy.

This nice looking glider is a PITA to build. I have to cut the wing servo opening to fit servo and cut wing balsa to get pushrod to get pass.
May 01, 2015, 03:36 PM
Electric
I just ordered a slope version to modify into an electric. This thread is dead but I will post my thoughts and mods.

Using @1100w going with a 3s2200mA 60C and AR10x12 from a Hyperion Gs3025-04 1540kv motor and ICE100esc.

Somewhere @42oz. 105MPH vertical

-OR-

Aim for @34oz and 525w using a 4s1600mA 25C and a Cobra 2221-12 1250kv spinning an AR8x10. Talon35 esc. Verticals will it be 75MPH
Last edited by DeadstickDuck; May 02, 2015 at 03:37 AM.
May 01, 2015, 07:40 PM
DLG Bug Bit Me
Tim Harbour's Avatar
Please post your mods DSD. I've entertained getting one of these to electrify also.
Tossing up between one of these or an Nan Omega Mini e.
I think a Nan Omega would have a top finish, but a sunbird has a better price.
Will be watching like I do your kunai mods. 😉
May 02, 2015, 03:31 AM
Electric
Couldn't pass up on a $172.50 moldie.
May 02, 2015, 04:09 AM
Registered User
Hi All!

I'm also very interested to see how it goes!

I (and a colleague) both have brand new HK Sunbirds and we've been rearing to go for well over a month now .. Alas, we've had no decent sloping conditions for that long, so I've been seriously considering chopping the nose off and installing a motor and taking it to the field. There's not much room in there for a 3S 2200ma though ... perhaps where the ballast tubes are usually fitted(?) My nose weight ballast (the lead slug) is about 148 gms which gives a CoG of about 77 - 80mm from the LE (from memory) .. so there should be plenty of scope for replacing that with a good motor/esc/battery combo.

As shown in the photos early on in this thread, the original E-Sunbird fuse cleverly had moulded mounts for the rudder and elevator servos just aft of the wing trailing edge .. which freed up the extra room needed for the motor/batt/ESC in the nose. I've also toyed with the idea of somehow fitting both servos directly in the tail and doing away with the control rods altogether(?)

Oh .. a quiet word of caution .. the tail of the non-carbon Sunbirds is very, very weak when it comes to opposing torsional stresses. I've had two glass fuse Sunbirds so far, and both have cracked for almost no reason in 'the usual' place (the boom just in front of the tail). For this reason, it might be a good idea to avoid having to add tail weight (eg: to offset a slightly heavy motor, etc). Hearing of new ways of reinforcing tail-booms is kind of one of my ongoing quests, too ..

These are just random thoughts anyway .. looking forward to hearing how you go about it, DSD!

Cheers


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