Quote from: intorc on March 25, 2016, 09:36:42 PM
May be a silly question but does it also apply in swept wings too?

Unless its a jet, i expect a cellotape on the wing joint would be enough.
In olden times, we used to stick a pin into the top spar of each wing, and connect with a small rubber band...

There is an ongoing discussion in RC Groups about the power needs of the Sunbird.
Copying my today's RCG post here, as may interest RCI members building a Sunbird.
(Pics/video excluded as already available in this thread)

How much power for Sunbird...
Hi,
I thought my Sunbird was pretty. Till I saw the others in this thread.

Mine is 450gms/16oz. Rudder, elevator, throttle. No ailerons.
Two piece wing with 6" hardwood dihedral brace/joiner.
Has an Emax 2805 with a 5-6" prop label, indicating it is 2840kv.
However, must be a 1600kv, as near full throttle (fearfully reaching 150+ watts) indicated 15000+ rpm on 3s and a 6x3 prop that has an HY logo.

Soldered parallel JST and XT60 connectors to ESC, to enable use of 2&3 cell.
Used a 1000mah 3s to avoid tail heaviness.
Balances at spar, about 40-45mm from LE.

Easy take off at half throttle. About 50- 60watts. 9-10,000rpm.
Or about 50 fps.
Above half throttle, a tendency to loop!
Corrected presently by mixing 5% down elevator into top half of throttle range!
Bet no one tried that before

So the lessons i learnt:
1. 60watts is enough for a nice climb
2. CG could be moved aft 10-20mm behind spar (and decalage reduced, and down elevator mixing to throttle removed). Will try on Sunday if weather permits.

Here's a pic, and a brief video. See if you can spot power cut at about 22 seconds, rest in lift!

Here's a pic and the video anyway, to save you the trouble of going back to page 1 

450 gms at that wingspan  . Awesome build sir. Looking beautiful. Must surely be a pleasure to fly. The shape of the Wing always deterred me from getting one for me. Wondering no build issues you encountered.

Great stuff, Iyer saheb

Quote from: sanjayrai55 on December 12, 2015, 09:57:10 AM
Very nice, sir 

Now I must build a power glider. Corro, 60" + + span 

Now you know who inspired the Fournier

Haven't come across anyone in RCI flying the Hobbyking Sunbird, so most of my posts on the subject have been on RCG!

In case there is someone here flying a Sunbird, he/(she) may find this useful 

Since there is no instructions booklet, just some pictures, CG location has to be guessed at.
So far I'd been flying with CG 45mm from LE (just ahead of spar)
Following inputs in RCG, moved CG back to 55mm this Sunday.
The improvement is amazing.
No more tendency to drop nose in turns. Absolutely flat glide hands off and power off.
So nice that RC Aunt (who hadn't flown RC in over a year), snatched the Tx from me!
Till I snatched it back after 8 minutes!
The video is however only 30seconds, ended by our dog who considers the iPad a competitor for attention, and so hates it...

Sunbird with GPS and altimeter. No audio vario though...

Tomorrow, hope to get data on
1. Altitude
2. Upwind/ downwind ground speed via GPS

Results from last Sunday:

Well, there's some good news, and some bad.

The good news is that the altimeter showed that reaching 400ft is easy.

Now the bad news.
1. Flying the model, and reading the data display can't go together.
I'm 63, wear -7 glasses and bifocals. Once I focus on the display, i lose sight of the model completely. Needed shouts from wife and friends to locate it again...

2. Ground speed as per GPS varied from 46 to 72kmph. Didn't sound right...

3. Had a temp sensor, so taped it to the ESC (12a, 1a BEC). Noticed the temp display climbing rapidly. At 57 deg C (ambient 28C) I decided to land urgently. Found that the ESC's plastic wrapping had melted and peeled off...

4. Removed all sensors and hub. Had no difficulty flying. No heating, nothing.

The question now is:
How much power are the hub and 3 sensors drawing? (GPS, Alt, Temp). Are they (and 2 x 9gm servos) cooking the 1a BEC? Rx voltage even showed 4.9 instead of the usual 5.0!

Lessons learnt:
1. Need separate power supply for hub/sensors
2. Need full time copilot to monitor display (and toggle between 3 screens) to get any useful data

Regards

Edit: meanwhile waiting for sanjayrai55's Griffin to be completed...

Iyer sir, you are much more than 63   Wisdom of a 100 and that stuff

It has been so long since I flew an Orange Box (nearest approximation to the Griffin I can think) that I have quite forgotten what one is supposed to do 

Decided to fly the Sunbird, the only fixed wing airplane I registered with Dgca.

Mostly flown by RC Aunt.

Today she said she can hear a sound.
Which wasn't there before.

Checked that prop is balanced. It was.
Removed the motor, washed it in water, dried it and oiled it.

I guess the front bearing is suffering from dust intake.

I think it's time to replace the bearings. Has had 50 or more flights.

Can someone please tell me what size the bearings on an eMax2805 are, and where to get them?

Miniature bearings are difficult to get. Nagdevi Street in Bombay is the only one I know of; you would need to take the sample. Or if you know ID/OD/Height and type of bearing (eg Single Race, one side metal shield) you can cross-reference

Much easier to replace the motor!

In most cases a good cleaning and oiling works for unshielded bearings

If you let me know ID/OD/Height I might have lying around. I got some assorted sizes a few years ago

I remember my first scratch built. It was a fusion of the flight test tiny trainer (940mm wing span) and an avispad (ruggedness) with an aspect ratio of 5:1 chord:span. The final AUW of the plane was/is 780-90 grams. Had real trouble flying it , broke around 10-15 props until I could fly it for at least 3-4 minutes at full throttle and as a cherry topping, the airfoil turned out to be a symmetrical one (the boons of using corro) although I wanted it to be a clark y. I still use that wing on a much lighter fuse, goes vertical at times . The thing learnt : wing loading/CWL matters a lot. 450 grams for sunbird is just awesome. Bearing could be greased and you may find bearings of coaxial helicopters at novelty bazar in Indore, not sure about the sizes though.

last time I flew it by using a 1000mah 3s lipo and that old wing with the yellow fuselage. the flight time was very low and the battery felt like jelly after the flight.