High speed control surface servo torque

I have no idea (no intention to know) the existence of control surface servo calculation , until I crash my F16 and blue angle. The 2 crashes resulted from inability to pull back the plane from a very high speed dive >150kph. It seems the plane cannot escape from the vertical dive.

Then I realise the importance of calculating the control surface servo torque requirement. To my surprise, the torque requirement is not linear.

For example , the elevator flap of my F16 measured as a triangular surfaces with chord 7cm and length 12cm, deflection 30deg, servo travel 45degree .
At speed of 100kph, the 2 flaps exert a torque of 8Ncm. (http://www.csd.net/~cgadd/eflight/calcs_servo.htm) My Towerpro 9G servo of 11Ncm is enough.
But at a speed of 150kph, the requirement is 18Ncm, which exceed the servo spec.

That result in crash....from a high dive at full speed.

OS50 suddenly lost power - fixed

Suddenly lost power after 50 flights. The OS50 shows signs of overheat after 2-3 tic toc and the Carbsmart tends to richen the needle. Head temperature reads ~130 degC. Normally it reads <110deg C as adjusted in the carbsmart.

Turn out to be the damaged ring and sleeve (previous scotched) .
After replacing them, it works pretty well again.

F18 Blue Angle reach 120km/h airspeed!

My Align Team.







Align F16 400, modified with twin vertical fin.
Wt . of plane 350g + 210g (3s lipo)
450T/1800kv/2200mAh 18c/35A ESC
It reaches top speed of 107km/h at 280W with 3s.




Then, 4s 18c lipo of wt. : 280g
At 4s it pulls 380W, reaches my record breaking of 124 km/h.
With 6x5.8, motor is slight warm. Unlimited vertical.
With 7x7 propeller, the speed is not impressive and the motor is hot.

Another test flight with 3s/3000kv 450TH/5x5 APC, pulls >38A and speed ~ 110km/h. Acceleration is not impressive. Cannot performed vertical> 4s.

3s/3000kv/4.75x 4.75, pulls 32A, though calculated pitch speed>150km/h, but the thrust cannot overcome the drag to produce enough acceleration to reach the desired pitch speed. Unfortunately, I found my propeller mount slipping against the shaft and may result in the poor performance.

Align Muffler Pressure Hose

The engine sudden lost power on tic-toc and was richen with lots of smoke. The CSM carbsmart is working and richen the fuel to prevent engine overheating. On landing and found the pressure hose copper adapter has stripped the thread in the muffler.




I replaced the original 4mm copper adapter to a 5mm one (cost only HKD 10).

New Z50 780kv motor

Left - new Z50 stator core with thinner stator plate. It runs cooler than my old Z50 which is broken due to crash with fractured motor end cap.

CSM Carb Smart temperature sensor

Installation pretty easy.
I take away the power source "signal wire" as early user complain the feedback "signal wire" may jam the (JR) receiver.
Remove the needle valve retch.
I use longer 3mm screw for the needle clamp. The stock is bit too short to secure the nut.





DIY a servo mount.
I use the ball link rod from my Trex450. You can use spare Trex600 servo link (the one connect the T-connector) , which is a perfect match/ length.
I change the ball inwards later, finding that the outer servo horn ball may touch the canopy.






Full lean position setup. Use the CarbSmart potentiometer to adjust. Actually, you can have servo travel by 80 degree only. I set :
Most Lean - 1 turn
"neutral/ failsafe" - 1 turn 4 click
Most Rich - 1 1/4 turn




Mount the sensor on os head. Use DIY aluminium sawdust mixed with A/B glue.


Since the sensor is easy to be destroyed on dismounting from the engine block , you can DIY your sensor by using a 100K thermistor, cost $2 only.

Must remember to adjust the gain after the initial setup as it is easy to leave the potentiometer at extreme anti-clockwise( during rich needle setup). This leaves the gain at zero. Now I adjust the gain to around 80%.

Installing carbsmart for almost 2 galloon, I finally can see my needle goes to richess position on landing. Actually Carbsmart save me today. My engine suddenly lost power after 4 mins. violent tic toc, piro-flip for 1 min, and funnel. The smokes get thicker and I land it immediately. I read the needle is at most counter-clockwise for almost 15 seconds!! I was surprised to find that the muffler back pressure hose was completely detached from the muffler !
What the hell! This cheap little gadget did save my engine! Last time my leaking hose blown my piston before I had this carbsmart!





More fine tune. The needle neutral position was turned more lean by few degree (see the circle). This make a huge difference and I can see the Carbsmart is now richen the needle at end of 3D. 3D flight is more powerful. Now the gain is set ~60%.