Futaba 9650 vs Align 520 servo

Here shows clearly which one is faster.

DS520 is 20% cheaper than Futaba.

BusyBee 重生

Rebuilt after a sea crash during maiden. This will be a coming FPV platform after my 1.2G transceiver and GPS OSD (On screen display) arrived.

Noname F35 70mm EDF with retract landing gears

The retract is a good design with one servo driving 3 landing gears. The steering servo is next to it.
First tested with Haoye 70mm EDF. I intended to use 3s/11.1V and found it drew 18A only , but the thrust is too small , only 330g. Inside fuselage the thrust drop to 240g.

The world model 70mm EDF/ 3600kv. It is designed for 3s/ 11.1V and gives 440g thrust @ 20A only. It is well balanced and with the fan mounted on the outrunner bell. I cannot find a way to open up the outrunner.



This bird is bigger than the Freewing F35 (no landing gear version).
Length: 855mm
- Wingspan: 602mm
- Wing Area: 74.6 dm



I use elevon (Delta mixing) This reduce 2 servos and flies no difference compared with aileron.





Flying weight 550g including 1500mAH 3s lipo. This is unbelievable for this size bird with retract landing gear.
I prefer using 2200mAh for this bird.
It looks more scale like than the freewing F35.

Repair Spektrum BR6000

Found my BR6000 cannot bind , but function normally with the previous model name. So must be the binding chanel have problem. Number one suspicious is the binding circuit broken. Using an ohmeter confirm the an open circuit between the signal pin for binding channel and the resistor R1.

Test if binding works again with a jumper wire. Bingo !!Solder the jumper pin back to the R1 resistor. This is not too difficult if you have a special soldering head with a fine tip. Also use a small 30W and limit you soldering time <3 seconds. Otherwise, the R1 will fall off and you need a magnifying glass to look for it again.

SAPAC F16 Maintainence tips

The outter collar of the tail fin. Since it is made small and took lots of force. Mine got loosen after ~ 15 landings. Better secure it with fiber glass.

The servo area. Very limited space to work with as the lipo is in the way. Make sure the centering of the servo is made (with the Tx) before gluing the servo in placing.

The linkage rod better be oriented towards the inner side of the fuselage. Or else the tail will hit the rod. Make sure enough travel is allowed as this bird needs lots of travel for elevator.

I forgot to take a photo of the inner

F35 RIP after 50 flights

Finally heavy crash on launching as the pilot--me, didn't check carefully the aileron/ elevator servo plug is plugged wrongly. "Hurry !" is the biggest enemy !

損失慘重 FPV heavy lost

BusyBee FPV. Add gyro to increase roll stability as it is quite windy in winter. Motor mount modified to adapt 1080 propeller. With a 1000kv /3s setup, current is 16A with thrust > 600g.

Test flight for 2 times and quite satified with the gyro, which is dial down to less than45%

Flight time ~ 7 mins. with 2200mAh 3s lipo.

Mayday ...Mayday.... Emergency landing on sea...I repeat.. splash !!!

All electronics on board are submerged. Miracally, only the receiver and motor (killed by the receiver commanding full throttle , but kinked) is toasted. ECS, UBEC, gyro and servo are intact after H2O treatment. Lipo is overdischarged, due to internal short circuit to 3.3V/2.6V/ 1.5V. Slow recharging at 300mA brings it to life, but need further high current loading test to confirm re-usability.
Due to the NW monsoon and water current, it drifted to almost 2km away from the crash point in 1 hour. Finally I can fetch it with fishing wire .
Thanks Mr. fisherman to help me catching the plane with his fishing wire. He is so happy to catch a large fish that morning.

SAPAC F16 II Thunderbird 4s 64mm EDF setup

4s@36A, should be able to be handled by most by most 20c 2200mAh lipo.

3s 2200mAh seems to be too light for this F16. 4s 2200mAh is just ok.

Eurofighter spy plane

taping on the front gives more stable image

Failed take off due to losen lipo

Align DS510

You will be disappointed with the DS510 if you aim for a decent servo. But it will be a good one if one looking at the price initially.

1)It strips EVERYTIME there is a minor blade strike crash. Most of the time, at least 2 servo. Gear set are not sold cheap as it packs with bearings.
This annoys many of us despite there are "good comment" of this servo by some "supporters"
I think this is the same for 9650, but 9650 gear set is sold cheaper in my LHS.

So after replacing 2 sets, you will be regret not to use metal gear servo, as the price will be similar.

2)The slop of the 510 gear is horrible. There is absolutely no slop in the 9650. The slop cause delay in cyclic response despite good-looking spec. One can acutually see the swashplate rocking when the rotor is spinning on ground. My actual experience in during 3D when the pitch is moving precisely from + to - near the center, there is "deadband" response - meaning the stick should command a -ve pitch but yet no response because the "effective pitch" lost in the slop !!

The gear set of 510 and 520 are the same for the 1st, 2nd and 5th gear (count from the horn side). Majority of the crash will break the 2nd and 3rd gears.

SAPAC F16 II 首航

SAPAC 64mm 6 blade (GWSclone?) EDf
Stock outrunner , kv unknown
Power testing. 3s 2200mAh 26A, thrust ~650g
4s 2200mAH, 34A, thrust ~ ???
3s 2200mAh RTF weight ~720g, with landing gear

Very stable flight. Very fast even with 64mm EDF. Can drop in 70mm EDF without any modification.
This plane has CG issue. With stock 64mm EDF, 2200mAH 3s is nose heavy and the lipo has to be slide all the way into the fuselage. 4s 2200mAh is definitely out.
I end up by moving the EDF all the way to the back , so that I can use either 3s or 4s 2200mAh.
This plane 's airfoil is very thin, yet it stalls pnly at a very low speed.
The servo horns needs to point inwards, or else the push rod will hit by the horizontal tail.
I use the farthest servo horn hole (and innermost tail control horn hole) to have adequate ail/elev response.
The landing servo is a bit difficult to install because of the limited space inside the cockpit.
The long pushrod needs some strengthening....

Remember the tail fin needs to trim down a lot for straight level flight.

F35 reach airspeed 156 km/hr.

Airspeed sensor

Max 340W. Max airspeed 156 km/hr !

Trex 500 ESP Eagletree Log

Try to see if a cheap ($400 hkd) GE power 6s 2800mAh 25c works for violent 3D. All stock ESP settings.
Max. Watt 1400W. Max. Amp 64A. Average pack voltage 21.8V

Not bad!

J-power Eurofighter 2000 with 2x 2200mAh 3s

To test the ability of using larger pack for longer flight time, I use 2 packs 3s 2200mAh 20c lipo. It fit into the fuselage with some minor surgery. The fuselage is very spacious and easy to modify.

First flight was abandoned as weird noise originated from one of the ducted fan during full throttle take off. Luckily, this is a twin ducted fan version.

One blade is missing !

Something seems pluge into the foamA 5mm stone !

The EDF destruction is horrible as a stone is sucked into the duct through the cheater hole at the bottom. I should have sealed all cheater holes underneath !

Otherwise, the EF2000 flies great on 2x 2200 provide longer flighter time ~7mins. The extra flying weight of 180g is significant, thought it is more "stable".
I will try a single 2200mAh 34c lipo next time for better aerobatics..

Imax B8 charger A123 test

New version with SKYRC label

test with LiFe 7s charging

@2A charging, should be able for 6A charging @150W max

Clamp current shows very high accuracy


Internal temp probe guarantee charging temperature is safe. I will make a DIY external probe as well.Very unbalance cells in my 140 cycle 7s A123 pack
Final balanced packs