Friday, November 28, 2008

Youtube videos








Posted by at No comments:

Sunday, September 28, 2008

Current project, 1/8 scale AH-64D Apache



General characteristics

Data from http://en.wikipedia.org/wiki/AH-64_Apache

  • Crew: 2: pilot, CPG (co-pilot/gunner)
  • Length: 58.17 ft (17.73 m) (with both rotors turning)
  • Rotor diameter: 48 ft 0 in (14.63 m)
  • Height: 12.7 ft (3.87 m)
  • Disc area: 1,809.5 ft² (168.11 m²)
  • Empty weight: 11,387 lb (5,165 kg)
  • Loaded weight: 18,000 lb (8,000 kg)
  • Max takeoff weight: 21,000 lb (9,500 kg)
  • Powerplant: 2× General Electric T700-GE-701 and later upgraded to T700-GE-701C & T700-GE-701D (1990-today) turboshafts, -701: 1,690 shp, -701C: 1,890 shp -701D 2,000 shp (-701: 1,260 kW, -701C: 1,490 kW) each
  • Fuselage length: 49 ft 5 in (15.06 m)
  • Rotor systems: 4 blade main rotor, 4 blade tail rotor in non-orthogonal alignment[39]

Performance

Armament

---------------------------------------------------------


Just got an unfinished 1/8 scale Apache fuselage. I am going to build it. stay tune...

Here are some pictures of the fuse. The first two pictures courtesy of the previous owner




And here it is, with my 1/18 scale little brother



With a female pilot in place and the JR Vibe 90 mechanic


Just finished the tail. The assembly consist of:
- JR Vibe 90 tail gear box and control arm
- Tail shaft is Mini Titan 5mm main shaft
- Tail Rotor Holder is Trex 600
- Tail Pitch Assembly is Trex 600
- Control arm mounting is home made


... and here is the video




Got the rotor head done 11/29/08
Using T-Rex 700 Main rotor holder. Little heavy.

...with the anti-vibration on top (Not for D version), seem little too tall.


The mechanic is ready for the first test. Next to it, is a Trex-450


Video of the first test Dec. 14, 2008. With 2 X 6s battery 5300mA



Second test without fuselage


...more test



First flying test with fuselage. Jan. 2nd 2009



Finally, I got it done. Although still more detail and adjustment needed. I will continue later.
The total weight is around 24lbs, must more than I expected.

Here are some pictures.










More test at the park





More test fly with the new gear ratio. Double 115T main gear and 14T pinion
Got the main gear from here http://www.microheli.com/product_info.php?products_id=909
Precision CNC machined delrin.

Looks like the new combination works better for the motor, its cooler. Max fly duration still short, around 5min.














Posted by at 3 comments:

Cobra project


Dimensions:
Length Without Winch
5,000mm
Length With Winch
5,229mm
Width
2,220mm
Height
2,100mm without weapon station
Track Front and Rear
1,819mm
Wheel Base
3,300mm
Combat Weight
6,200kg
Curb Weight
4,800kg
Engines:
Engine
Water-cooled turbo-charged 6.5l, 190hp
Gearbox
4-speed automatic
Transfer Box
Full-time 4-wheel drive with lock, 2 speed
Front and Rear Axles
Independent double A-frame, with hypoid differentials
Suspension
Helical coil suspension
Brakes
Servo-assisted hydraulic disc brakes
Steering
Power-assisted steering
Fuel Tank
145l, mounted inside the armoured hull
Tyres
37 x 16.5 radial tyres with run-flat device
Electrical Supply
24V, fully suppressed
Alternator
200A capacity, 2 x 12V, 100AH batteries
Performance:
Power to Weight Ratio
31hp/t
Acceleration from 0 to 60km/h
13 seconds
Turning Radius
7.67m
Angle of Approach
70°
Angle of Departure
70°
Fording or Optional Amphibious Operation
1,000mm
Maximum Speed
115km/h
Ground Clearance
325mm
Side Slope
40%
Gradient
70%
Range
725km



This is my first scale model:














It's actually a Mini Titan fitted with a Thunder Tiger - AH-1W Supper Cobra Gunship Conversion kit for $69.

Note I removed the fly bar to make it look closer to the real one.

I tested in my back yard on June 22, 2008.
It was a bit of windy day. I almost crashed when trying to land on a 5 gallon bucket.




I haven't done much work on this project yet. The conversion kit comes complete with tail assembly and so I put it all together and hovered around my back yard. (Video above)




and...here is my wish for the future on the Cobra project.
The fuselage above is about 3 X bigger then the one I have
I wish I can built this Cobra one day. It is 1/8 scale and 58 inches long. Not sure what mechanical to be used for this fuselage.

Similar project can be found here
Posted by at 1 comment:

Apache project 1/18 scale


General characteristics

Data from http://en.wikipedia.org/wiki/AH-64_Apache

  • Crew: 2: pilot, CPG (co-pilot/gunner)
  • Length: 58.17 ft (17.73 m) (with both rotors turning)
  • Rotor diameter: 48 ft 0 in (14.63 m)
  • Height: 12.7 ft (3.87 m)
  • Disc area: 1,809.5 ft² (168.11 m²)
  • Empty weight: 11,387 lb (5,165 kg)
  • Loaded weight: 18,000 lb (8,000 kg)
  • Max takeoff weight: 21,000 lb (9,500 kg)
  • Powerplant: 2× General Electric T700-GE-701 and later upgraded to T700-GE-701C & T700-GE-701D (1990-today) turboshafts, -701: 1,690 shp, -701C: 1,890 shp -701D 2,000 shp (-701: 1,260 kW, -701C: 1,490 kW) each
  • Fuselage length: 49 ft 5 in (15.06 m)
  • Rotor systems: 4 blade main rotor, 4 blade tail rotor in non-orthogonal alignment[39]

Performance

Armament

---------------------------------------------------------

I couldn't afford the 1/7 scale, so I looked around and found this on Youtube: a 1/18 scale model.
I liked what I saw so I bought the Apache 1/18 scale from ebay (BBI 21st Century Toys Elite Force AH-64 Apache 1/18) for $65. This project took most of my spare time and I started it the wrong way. I ended up swapping three different mechanical parts in and out to get it right. I will try to detail them as much as I can.







BBI 21st Century Toys Elite Force AH-64 Apache 1/18


First off, I was frustrated with the available 4 blade rotor head. I went ahead and bought an old lathe to make my own rotor head. I've never operated a lathe before, but I can tell you it's not that hard anyway.



With the old lathe and mill combination machine in hand, I started to make my own parts. This is the 4-blade head I made. It has 5mm shaft, but later on I transferred into 8mm for the Trex500.


Complete assembly inside look


Detail of the mechanic


Detail of 4-blade rotor head and the anti-vibration on top
Note that the rotor head fits onto the Trex500 8mm shaft and the grids are Trex450


Torque tube tail drive. Custom made for angle.


Closeup of the angle


Detail of the 4 tail blades. The tail blade is made from the CX2 blades


After several weeks' work, here is the completed model ready for its first test!















4 blades tail














From top














Here is the flight test on July 22, 2008, a month after the cobra.
My back yard is small, so the test was just vertical up-and-down flight. I haven't tried to land on a small landing spot like the 5 gallon bucket nearby yet - I actually may not be able to land on small areas like the cobra can. I found it harder to fly compared to the cobra - it must be heavier.


Will have more video when I test it at the park.
---------------------------------------------
First test at the park. Unfortunately, I don't have the right battery (not enough discharge current for the 500), so I lost power to keep it up. Will try again when I have the right battery.
-


-----------------------------------------------
Second test at the park on Sunday Oct. 26, 2008
Add Video
Posted by at 9 comments:

AS550 Fennec Heli project


These pictures are the real thing. It is the Fennec AS550 gunship helicopter.




Crew
1 pilot
Passenger Capacity
5 equipped troops
Dimensions:
Rotor Diameter
10.69m
Tail Rotor Diameter
1.86m
Overall Length With Rotors Turning
12.94m
Fuselage Length
12.94m
Width With Blades Folded
2.53m
Height to Top of Rotor Head
3.34m
Cabin Dimensions:
Length
2.42m
Width
1.65m
Height
1.35m
Volume
6.6m³
Weights:
Empty Weight
1,220kg
Maximum Operational Weight With External Load
2,800kg
Performance:
Never Exceed Speed
287km/h
Maximum Range With Standard Tanks
666km
Service Ceiling
5,280m










----------------



How did I get into an obscure heli model that I have never heard of before?
Well, a Hong Kong helicopter parts company shipped the wrong fuselage to a friend of mine, and he brought it over for me to play with one day. He also brought over the Trex-600 kit, and I decided to give the AS550 a shot.

Scale Model Technical data:

●Length:1200mm(47.25 in)
●Height:388/405mm(15.25 in/16 in)
●Main Blade Length:600mm
●Main Rotor Diameter:1350mm(53.15 in)
●Tail Rotor:240mm(9.45 in)
●Motor Drive Gear:10T(11T optional)
●Main Drive Gear:170T
●Autorotation Tail Drive Gear:180T
●Tail Drive Gear:40T
●Drive Gear Ratio:1:17.0:4.5/1:15.45:4.5
●Weight(w/o main blade):1340g
●Flying Weight:Approx 3000g(6.6 lbs) + fuselage

Based on the main driver gear ratio and motor drive gear ratio, I calculated the max RPM to be 1692.423.



Here are some homemade parts I made from the lathe I described earlier:


Custom rotor head. If you need one made, let me know, I can make one for you.


With 600mm blades

Modify swash blade


Torque tube tail

(I will do a more detailed and organized report later for this project...)


Ready for the first test flight.


The 50-size mechanic works well.
Ready to assemble into the fuselage:









In the fuselage and ready to do more test flights:


First test flight with the AS550 fuselage.

My backyard isn't big enough for this RC Heli. I will go to the park someday to try again. I found that the AS550 model is easier to control then the Apache. It is a bit heavier then the Apache but is more powerful. Having three 600mm blades may be overkill for the mechanical design than two blades. I can lift off very stable with lower RPMs, though. When I have some money, I may want to try the 550mm blades or even with 500mm blades.

Speaking of money. If I can sale any parts that I made or the whole model to get some cash for the next model project would be nice. So, if you are interesting to buy it from me, please send me a note thomvan@rocketmail.com.

Thanks to my wife and my sons for those videos while I am on the control sticks.
Posted by at 1 comment:
Subscribe to: Posts (Atom)