P51 老野馬

身經百戰既3歲老野馬重生, 爆頭斷身掛樹,重組加上7x5e / 1800kv, Power 350W, 快
但重了100g, wing loading 大, 比零戰易失速很多

V22 VTOL 垂直起降 魚鷹式傾斜旋翼機

This is my VTOL maiden under gust of 20kph before the rainstorm.

My project takes me 2 weeks ( ~20 hours in total) , Most material fetched from my junk box..

Basic priniple:
Flight control similar to real V22, except in real V22 there is no swashplate .
Roll - Differntial pitch control, i.e. more positive pitch on one rotor provide extra lift to roll.
Yaw- Either swashplate tilted oppositely in forward/ backwack direction.
Pitch - Both swashplate tilted in same direction either forward/ backward. The C.G. of the craft has significant effect on the pitch axis.
Transition - Operate by a strong metal gear servo that tilt the both rotor forward from vertical position.
Bothe swashplates governed by TH2 tandem control board from techproduct.

Materials:
1) 2 Trex 450/ Clone rotor head
2) 2x Trex SE frame (I made one from 0.8mm fiberglass board with a dremel), 6 CCPM servos
3) Rotor transition tilting by 5mm copper tube, being attached firmly to the Trex frame at 90 degree.... photo
3) Trex tail boom x 2, with bearings at each end, holding the inner 5mm copper tube
4) Copper tube has a ball link screwed on it can link to the 82 MG pod tilting servo.
5) 2 Towerpro 2409, 1500kv brushless, @ 15T x 4s, Headspeed 2100 rpm
6) 4s 220mAh, with 2 18A ESC. UBEC 3A.
7) 325 blades cut down to 260mm size, for scale down to adopt to my crappy T34 mentor fuselage of 800mm long. ( I will definitely scaleup to use 325mm blades for a 100mm long fuselage)
8) Roll axis gyro : Esky 802? , Yaw axis gyro - Align 500 , channeled to have remote gain control.

Mechanical setup:
1) Both rotor must have the blades well balanced. Swashplate and servo centered and trimmed as in a heli.
2) The most difficult part is to solve the vibration ./ resonance issue. Half of my time is to figure out where the vibration comes from. Since the 5mm copper tube takes all the vibration and will shear itself . The answer is use the strongest material/ method to ancho the copper tube.
3) To neutralize the change in CG during transition and the rotor is heavy, and will shift the CG forward on forward flight. So selecting a point to attach the copper tube is essential.
4) Pitch axis does not need gyro as the low CG will stabalize it self.

Electronic setup:
1) TH2 ..... setup... This makes me mad as the Ch6 (transition switch control, this is essential as it deactivate the roll/ yaw gyro, which is wrong when the pod is tilted) is not working with my DX7. Eventually I flash the firmware and it works like charm.


........

Since I cut down 2 pairs of 325 wooden blade to 260mm, I dare not stress the blade too much HS. Now geared at 15T/4s/1500kv towerpro motor (probably 1200kv), with HS of 2100. I am sure I need more HS ,say 2400, with 260mm blades. The wings did eat up lots of thrust, as it hovers much better when without wings, inside my room. I will try 315mm blade, or 16-17T if I can find somewhere (Align largest 0.5M pinion is 15T).

Hovering current 15A only.

Collective pitch with cyclic control is much more stable in hovering mode.

Cutting down 335mm to 260mm wooden blade.

Essential to make the jole perpendicular to the chord

EDF 推力計

55 EDF , thrust 300g @ 23A/ 10.5V.

Without a pitch speed measured, it is difficult to comment the efficency of different EDF. GWS EDF gives high thrust but lower pitch speed.

零戰

Bought 2 years ago for HKD 170

All painted and RTF

Motor mount from Align Trex600 aluminium rod

40A himodel ESC HKD$99; so cool that no heat sink required.

The CG is very forward located ~2cm behind leading edge.

Flies much better than P51; can fly very slow without stalling. High speed flying is no problem , especailly with 8x6 3 blades propeller.

3s @ 20A

I tried APC8x8 which is even better, but the current takes as high as 33A.

August-08: Now use APC 7x5e which is more gentle to my Radar cheap lipo. Motor : Emax 2215-25 1500kv?

油機內置點火

The Align 2 in 1 ingition board is good but is expensive ~$HKD230.

I DIY a simple connection to deliver 1.5V @ 3-4A to charge the glow plug.

The power source is from a 2S 2200mAh Lipo. It supplies 5V to the BEC. One cell of the 2S lipo is step down from 4V to 1.5V through 3 diodes rated 3A, in series. Since the glow plug only fires a few seconds, efficency is not a problem at all.

P51 1460mm Wing Span

The World Models .46 P51 Mustang. This is a rather old version but seems I cannot search too much information about the flying character of this bird.
Weight 2.5-2.7kg
Wing Span 1460mm
Engine : OS50SX-H, retired from my Trex600N; as the cylinder head is heavily damaged by the broken ring (after difficult starting ). Replacement of the cylinder head cost 1/3 of a new Os50. In addition, the hex screw slipped and resulted in brutal jigsawing to open up the cylinder head. So I decided to use in on a plane.

BUILDING:
The kits include all you needs. The retractable landing gears are excellent, though the wheel cover is too thin and will break easily. In addition the coverings tend to be peeled off easily as the wheel may rub against the depression.

FLYING CHARACTER:
Amazing, this bird flies excellent with reasonable speed at APC 11 x 8 . Tachospeed reads maximum rotation at 11,500 (wasn't this lower than expected?) only at half turn needle valve.

Needle valve needs a 3 inches piano wire connected with a wheel locknut to make it easier to be tuned.

The Flaps are aileron mixed and not efficient as an independent flap. Flying in typhoon signal 3 shows the strong built of this bird. The bird will wag funny under gust of 60 kph. Landing is easy even in gust.

Stalling is not easy and there are plenty of climb power with the OS50. Looping is a piece of cake.

I plan to convert it to electric Warbird soon as I am sick with the oily film that may stain my car cabin.


6-2008 :
Finally retired after a heavy crash resulted from stall turning before landing. Main wing is intact but body detroyed.

Futaba 接 JR/DX7 教飛線

之前整個條係E-sky 接futaba , 用來教仔玩

而家用DX7 做master, 因JR/ Spektrum Master 用negative shift, Futaba student 要用signal inverter 或 PIC 改PPM 輸出, positive shift 做番negative shift 輸出

更正: Spektrum DX7 輸出為 9ch , Frame 22ms, 9channel, positive shift 1.5V
及T7CHP 輸出為 8 channel, Frame 20.5ms, 8channel, positive shift 2V
所以只要接T7CHP PPM 輸出 致DX7 mono plug in 便可. 但要修改 T7CHP channel 排序

另E-sky 4ch 係可接 DX7 , 要修改E-sky channel 排序.


成功

My FPV project

under brain storming ,
Gears needed:
1) EyeTrek Google?
2) 1.2G transceiver & receiver, patch antenna? DIY but seems not work good enough
3) CCD ... need to think about separate battery /BEC power source.
4) Head mount gyro helmet for pan/ tily servo of CCD....may be later..need additional trainer Tx? or use switch mixing from the additional channels?
5) High wing trainer with mid-upper pusher and roomy front...Busy bee seems a good choice...EPP?


some video from other pilot

My Trex 600N 3Ding

Chinook Tandem Heli Build Thread

Aerobatic, DCP 30%, Ch5 mix 90%, gyro 35%


Flight with flybar weight added



4th flight


1st flight



Materials:
1) 2 x Trex 450 RotorHead CC and CW modification, $800 HKD
2) DIY Body Frame 1.5cm fiberglass (can use metal cutter) , $50
3) metal bearing mount x 3 pairs, $150 HKD
4) 5mm copper tube , as tandem torque shaft, $30 HKD
5) Miter gears x 2 pairs . spare parts from gas heli torque tube, $54 HKD
6) TH2 mixer ~$1200
7) Pitch gyro Align 500X (old version), Yaw: E-sky 704A HH gyro $230 HKD
8) 500T. 1900kv @15T
9) Towerpro 9g servo x 6 = $180 HKD, servo wire extension x 3
10) Fiberglass 325mm blade 2 pairs, $ 70 HKD
11) 45A Himodel Heli ESC $140, AR6100 6Ch receiver, Align 3A BEC , 3s 1800 lipo

Flight 1:Failed , due to bent hollow main shaft from Ground Resonance?? Vibration caused by too high headspeed and the 2 towers shake like crazy.
Flight 2:Successful hovering , but lots of hunting due to unwired GY401. Resolved using cheap E-sky 704A gyro on HH mode without gain wire connected.
Flight 3:
Successful level flight. Used 2 HH gyro. Need to stregthen frame for the torsional stiffness.
The driving shaft may need 4 bearing support rather than 3. Trex600N needs only 3 bearings. Maybe the shaft-->miter gear connection allows more vertical/ horizontal clearance.
Flight 4:
Vibration comes from torque shaft alignment and frame torsional deformity. Problem solved with additional frame support and realignment of torque shaft bearing mount.
Perfect hovering and forward flight. Very stable Headlock yaw and pitch control.
Flight 5:
Try adding the flybar metal weight (~1.8g). It makes the Tandem much more stable and real. I can off my fingers off the Tx for 10 seconds now.You may need to reduce the gyro gain then.
The front rotor vortex is rather interesting. I intentionally reduce the pitch gyro gain <40%>30cm in a sudden. First I though it is low voltage throttle cut. Then I remember it is what Joe mentioned. You must increase the throttle stick (as much as 2/5 throttle ) to regain altitude. This is real fun to see it happens!
I also observe another interesting phenomenon that does not happed in single rotor heli. When I do a fast piro, the whole bird seems obtunded after turning 180degree. I guess the front rotor turned into a position where the rear rotor was before. The turbulance will then counteract the coming rotor a bit. Anyone can confirm this?
Need to increase TH2 setting DCP gain , as 30% mixing still have Front Vortex Interference on slow FF. The remote Ch5 DCP gain works great as I dial it up to 90% in very windy condition >20km/hr.
Did some aerobatics today and fast FF is perfect.

Change bearing of Align 600L brushless

Mine is over 300 flights and the motor bearing is still fine and I decided not to change it. The bell is nicely balanced . The rear bearing is notched and grainy.

Procedure:

1) mount the 600L on a motor mount. Place the mount on a clamp.

2) Use a DIY tool, or a rotory saw blade driver with teeth 29mm apart. This can turn open the base cap. The base cap has loctite with the stator base.

3)Use a bearing clamp to remove the stator from the base cap. Or you can punch the stator out with the base cap supported.

4)The front bearing, magnet bell can then be removed. There should be a copper washer, of same size as the Trex 450 main gear washer.

5) This is the most difficult part. To remove the rear bearing, one has to punch from the other side of the stator. Align put lots of loctite on the rear bearing. You need a hex socket (size6/8 inch?) to bear the stator base. I use a 5mm Trex450 main shaft with a 6mm copper tube. Thing is easier if you get a 6mm shaft to punch out the rear bearing. Remember another copper washer is underneath the rear bearing.

Trex 600 CF Flybarless

After my experimental Flybarless Trex450 , I decide to convert my Trex600 as well. I forsee the fast cyclic response is good enough for 3D.




Using 15mm linkage ball. 8cm linkage rod.
Extend the upper swashplate ball distance.
Phase angle washout hold in position with hex nut, at 0 deg.
I use one arm only , but will put another arm soon . As during 3D, a cyclic punch will rotate the arm a bit and result in undesirable/ abnormal cyclic response. In addition, the old design Trex600 swashplate has the upper balls off center ( A design flaw).





Leading edge. But the grip screw nut become the top.
Tx swashplate Ail -44%, elevator 55%, collective 40%
Cyclic 13 deg, collective 12deg.
D/R exp Ail/ elev -30%




Result :
I am very happy with the fast cyclic even at very low headspeed ~1900. The forward flip is 2x faster than my 600N @2100 rpm with light paddle.
In head on wind, pitch up is significant.
Hovering/ Control is much stable than Trex450.
Will try to add a pitch gyro to see if the pitch up/ballooning will disappear.

Short video, cannot record the 3D part because memory card is full.

Coast Guard Build Thread

Hurricane EP550 body and .30 Funkey fuselage with wheel retraction driven by 2 servos.

Steps:

1) Retraction system , waiting PIC burning for slow retraction and LED lighting.

2) Trex 600L motor too tall. Have to put back my 1000kv BL. Then have to gear up with 16T / 50T front gear to achieve HS ~1900.

3) The tail hub have to trim at the link ball lever.

4) Swashplate may hit the fuselage on highest range. Need to trim 3 slots.

5) Battery weight better bear on the frame rather than on the fuselage, as the fuselage is not yet mounted secure enough to the main frame.

6) Hurricane EP550 seems a good fit for the .30 fuselage

7) Thinking of putting some seat and pilot inside.

Trex 450 flybarless (2)

Trex 450 Flybarless

Version 1 with direct drive. Poor collective resolution as the gain is et to 35% only.








Version 2 with mixer at hub to half the collective pitch travel, to improve resolution. However, the cyclic pitch travel is also halfed.

The cyclic travel can only be isolated from the collective pitch travel at the swashplate level. That is the swashplate upper/ lower diameter ratio.

TH2 CCPM mixer board from tech product

The rotor phase angle adjuster . 10 minsutes job from a shaft collar and fiberglass. Will make a better one.




****1st version

Direct Swashplate drive the blade grip.

Mechanical Setup:
1) taken away all flybar, seesaw and mixer arm. Direct swashplate drive to gip hub.
2) GY401 as elevator dampenig. Align 500X as rudder gyro
3) towerpro CCPM servo, Hitec 56HB rudder servo
4) TH2 CCPM mixing
5) Main grip leading edge control. Mechanical Phase angle adjusted 11 o'clock.
6) Servo horn distance shorter ??mm

CCPM mixer and Tx setup:
1) TH2 gain : Aileron 60%, elevator 65%, pitch 35% (way too small resolution)
2) Aileron D/R 80, Exp -50; Elevator D/R 70, Exp -50;
3) Cyclic 12 deg; pitch 10 deg

Result :
Hovering
1) Unexpected oscillation at pitch axis. Likely too high pitch gyro gain, sloppy servo , soft head dampening. Touchdown of expensive carbon blade with minimal damage.

****2nd flight
1) Hardening head dampener rubber
2) reduce sloppy servo, use Align 500X as pitch gyro with gain 20%
3) Add mixer arm to increase blade pitch resolution. 2x travel now
4) Servo horn distance same as flybar trex 450
5) Th2 setting: Aileron gain 65%, Elevator gain 70%, pitch gain 45%.
6) Achieved Max. pitch +/- 10deg, cyclic only 8-10 degree ( needs more)
6) Tx Ail. D/R 90, Exp -40; Ele D/R 90, Exp -30.

Result:
Stable hovering. Perfect figure of 8. No oscillaltion. Needs constant attention to roll (cause lack of aileron stabalization). Cyclic response at HS 2000 is almost as fast at HS2800.

N.B. TH2 has a behaviour that trimming on the Tx will greatly reduce the SW travel to the opposite direction. Therefore, all trimming best done mechanically or on the TH2 itself.

Next test schedule:
1) To test backward flight.
2) To test inverted flight.
3) To test 3D performance

Plan:
1) Need to increase inner swashplate diameter and decrease outer SW diameter. This will increase cyclic travel mechanically.
2) resolve some mechanical binding at mixer arm and central hub.
3) Change a more powerful BEC as the clamped BEC current is over 2.6A with 4 servos/2 gyros/ TH2 and receiver.

****3rd flight
Forward flight, stabel, no pitch up problem.
Backward figure of 8, pretty stable.
Pitch gyro gain at 30%. No osciallation as the head dampener is pretty hard.
With a plastic blade the cyclic is very fast and predictable. D/R 100%, Exp -25%
On pumping up/ down collective pitch, the heli may drift a bit ? realted to plastic blade being too flexible?
Plan for hard 3D in windy condition this weekend.




Phase angle set to zero











All linkages are straight now. No slop at all (except at the swashplate itself). Collective control is precise.