Sakura EPP from Banggood

9 January 2017

Hover, sidelong flights are possible if the battery is powerful enough. As it is, my 3-4 years old 250mah can barely make it, but if I used heavier but larger and newer batteries like those 450mah and 520mah batteries, it is still possible. I have to try out the new 150mah cells when they arrived.

Sakura flies slow and prefers still conditions and expectedly, it is not precise but that simply means I have to be more careful moving my sticks. Comparing to my Skycolor that uses the same WLToys' geared motor and propeller, it seems the motor on the Sakura is less capable, I could slide it out and try on a different pinion motor to see if it makes any difference. Andy suggested the difference as manufacturer's tolerance.

I crashed the Sakura many times and discover that the motor mount of Daiso foam sheets is too weak, something more resilient and less snappy is required but I will just use hotglue to fix it up. The 2nd Sakura should use better foam for mounting, newer batteries, and perhaps a different motor.

I thought of using plastic for the landing gear. Maybe I can cut a pair of plastic legs/pants and hotglue them to the underside. I haven't try out my heat gun, maybe I can use that to make the bends, or, just bend them and see.

3 January 2017

Easy to fly, too flexible, not enough thrust.

The boxed kit came before Christmas. The content is different from the supplied manual. There are no motor mount or pin hinges.
It was assembled/built following the supplied manual except for some minor areas.

14.2 gm without equipment or pushrods.

30.3gm with equipment but without pushrods.

 Now it is 37.7gm without battery. Pushrods (and twin foam pants) added 7.4gm? That's heavy.














51.2 gm with 520 mah cell (WLToys' V977 upgrade battery).

 The cell (plus Velcro but without hotglue) weighed 13.5gm.

 Ready for test flight.

Pants didn't last. One land/crash, one break. Removed and snipped off the extra landing rods.

I used 250mah cells and on a good cell, I get to hover and not much more, but they drain too quickly. The cells are too old. Good perhaps for less strenuous application because it appeared to pull stronger with the 520mah cell.

 

 

 

7 December 2016

I bought 2 Sakura EPP kit from Banggood yesterday. If I buy 1, it will be standard shipping. If I buy 2, it will be registered shipping. This morning, I checked and they are shipped.

I will fix up the first one and keep the second one as spare, either to give away if I don't need/want it, or to incorporate my experience with the first build.

I searched for information regarding this model and found videos of it, but I am not impressed; they fly too fast and did not perform respectable 3D maneuvers. And yet I bought 2 of this kit, why so?

The videos, reviews and comments I found were typically equipped with 5gm brushless motor spinning a 3" or 4" prop and with separate esc, rec, servos. One even ended up as 70gm! I think using WLToys equipment will be better. WLToys propeller is about 5.25", is of low pitch low rev variety, and perhaps 50gm static thrust. I have such faith that I have been thinking of making a 3D capable flyer using the WLToys F929/F939 receiver board, geared motor and prop combination, and small 1S cell. I think a 16" - 20" wing span would be about right and Sakura is 16" (so are the WLToys F929 and F939, aerobatic but not 3D planes).  The Sakura kit fits my bill and is cheap and convenient and the various hardware and carbon fibre rods are all included. Further I found that EPP is lighter than the KT board? 3D is about light wing loading and good thrust to weight ratio. The common factor is weight. If I use WLToys equipment, I will end up much lighter, regardless, as shown in estimated table below.

Description	Brushless	WLToys
Airframe	10	10
Motor	5	7
Prop, Saver/adapter	2	0
ESC	6	0
1S Cell	8	8
Receiver	2	5
Rudder Servo	2	0
Elevator Servo	2	0
Aileron Servo	2	2
Others	6	6
Total	45	38

I will build the first one 'standard', following the manual except on the landing struts which I think should be splayed open at the keel instead of bunched together as shown in the manual. And if the carbon rods are long enough, I could extend the front pair of landing struts and glue dummy wheel pants the ends. This is mainly for looks and maybe also for the vertical location of the CG and lateral area, if I don't have them, I might as well settle for a non-plane-like kite. Most aerobatic planes do not have retracts.

Adding wheel pants is a weight adding idea, here are weight losing ideas:

• I could substitute upper carbon fiber fin-stays with strings instead.
• I glue the servo arms on and save the 3 metal screws
• I use shorter wire bits and heatshrink in the 4 pushrods (1cm instead of 2cm per manual, so I save 4x2x1cm= 8cm)
• I spot glue at intervals instead of continuous bead
• If plastic hinges are provided and they are too heavy, I substitute with tape or figure-8 string hinges.
• Thinner strips of Velcro.

How will it fly?
Aerobatic yes, but perhaps it won't fly 3D? In the end, I may get disappointed, but it's only a toy and that's what a hobby is for, to aim for something and enjoy the process; to play.