More photos about hairline crack of receiver

Spektrum did have good customer service and do not attempt to repair the receiver unless you know what you are doing. The symptom is intermittent failure of the channel (in my case first binding problem, then throttle channel...)

After my abuse/ crash, the circuit board got some hairline crash as the servo plugs are pull apart. Since it is not designed for crash, the BR6000 does not have a tough case to reduce crash damage.

The hairline crack is identified and the circuit is repaired. The thin circuit board is strengthen with fiberglass sheet.

EDF Calculator

http://www.s4a.ch/eflight/fancalc_e.htm

Hoffman Magnetics 1700W for 70mm EDF

Bolt on a commonly available 70mm EDF. There is a O-ring as dampener against the inner side of the motor case, but a bit thin IMO. The motor is well balanced.
Suprisingly the outrunner base and the strut are made of plastic! Unbelievable. I need some endurance test before I can say it is safe.

This motor is crazy and delivers 1700W. I tried 4s2p 2200mAh 25c with Amp>108A and power 1500W! Thrust is over 2.4 kg !

In a 1.1 kg jet it flies like thunder. My Dean plug melted after the flight!

I wanted to tame her down by using 3s2p 2200mAh instead. The current drawn will be 90A max and 30A half throttle. Thrust max. around 1.4kg !

Starmax 90mm EDF F18 Building Log (Part 2)

Linkage of the steering servo is tricky.
Adding 2mm carbon rod to prevent flexing of the long linkage wire.

2 part fuselage need close attention to have sufficeint epoxy. I use liquid nail to fill the gaps as epozy may be too thin for large gaps.

Vertical fins have "toothpick" support.

Adding lots of grease at the shock absorbing strut. Locktite the locking screw and avoid overtightening.

All pimples sanded away. Finish duck taping the exit ducting. Smooth ad turbulence free.

Some tips to installing the retract servo as well. Do not adhere the retract servos till the retract directions are confirmed. Unless your receiver got enough channels for mixing. One of the rear landing gear retract servo needed to be reverse in direction. I resolder the pot and the motor +/- to reverse it.

Wings were attached with sufficient epoxy and will be fiberglassed underneath, as the wing is not sandwiched between the upper and lower fuselage. This make the wing prone to "crack" on stress.

If you epoxy the front retract gear slot before placing the retract in it, it will be tricky to place it afterwards.

Freewing F35 2nd major rebuid

The head is completely ripped off after a wrong connection of the receiver aileron/ elevator plug on hand launch.
Some super light clay .

Too lazy to have sanding.

Fly as good as new.....for another 10 flights.....Ouch !! waiting for 3rd rebuild after nose dive on transmitter running out of battery and shut down without warning !

Starmax 90mm EDF F18 Building Log (Part 1)

The Starmax F18 has high level on scale design and resulted in main wing and tail fin joint area being weakened. Paint over joint area needed to be sanded away. Add spoonful of epoxy (do not use foam glue as it cannot penertrate the paint, ad the paint will just peeled off on stress).

Tail fin need 3mm carbon rod as well, since the joint surface area is too small to handle such force.

The main wing is reinforced in factory during molding with 3mm carbon rod in factory to the wing root (less 3mm)

The landing gear foundation is sanded and added with "Liquid nail". I love this as it is more resistant to stress and less bristtle than epoxy. It fills large gap better than epoxy as well.

The landing gear looks great and is smooth on operation, with towerpro 9g servos. I guess E-sky servos is too weak to handle this , and will easiy cause binding at the push pin.

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