The Pitchbrother Society

I just build an Odin 90 from Compassmodel. This heli is really someting different. It is the first heli to use an electrical driven engine cooling fan.
This gives an extreme low frame with a CG closer to the rotor, sould be great for 3D flying.

One thing I don't like about the electric fan is that the heli don't have a fan shroud - With the cyclic servos mounted around the engine they get soaked in fuel very bad.

An other thing I don't like about the fan is that to make it work properly you have to use 2 battery packs, one for the receiver, and an other 3S pack for the fan

OS 91SZH with OMI carb and Hatori 939 muffler.
Torsion 710mm main blades, and 106mm tail blades.
Multigov Pro with Align DS620 servo.
DX7 with AR7000 receiver.
CSM 720 with Align DS620 servo (BLS 251 on the way)
Align DS610 servos for swash.
2S Life Hyperion pack for Reciever
3S Lipo pack for Fan
Modified SuperRocker switch.
Weight: 4,25kg.

The heli comes pre assemblied so the build is straight forward. The hardest part is to find space for the electronics and figure out a nice way to start the engine fan. I wanted the fan to start when I turn on the receiver. I bought a SuperRocker switch, made a hole in the canopy, so I could turn on fan and receiver at the same time. First I ran the lot on 2S, but I needed some more cooling. So I just bought this regulator and ran the lot on 3S. It turned out the be a bad deal. The setup used 1100mAh pr flight, so I had to charge after every flight, why not just buy an electric heli

I only found a few minor issues during the build:
No clearance between canopy and main gear.
I also shortened the push rod for the tail ~20mm. That may not be needed, but I like the servo to be mounted with a small clearance to the tail boom mount.
Some slope in the tail section was fixed with some new holes in the tail pitch slider.

Flying.

Tail: I ran the DS620 servo on the tail, but it gave up after 10 flights or so. After that I changed to a BLS 251 - great servo. At the beginning I had a slow tailwag, but It turned out to be a loose tail belt caused by the cold weather. I left the heli outside for a few minutes and adjusted the belt. Servo arm lenght: 16,5mm.

Cyclic: After a few flights I mounted some flybar weights. It made the cyclic more precise, without loosing to much cycilc speed - Ask Rasmus how big the grin was at my face when the Odin landed after that flight 
I run these ccpm settings in my DX7
Aileron 45%
Elevator 45%
Pitch 60%
Servo arm lenght: 14,5mm

Pitch: The pitch is very fast but still precise.The heli stops like nothing else I have tried. The Torsion Blades do a great job, they are hungry, but have plenty of "pop" even at 1850rpm and 11° pitch.

Conclusion:

The Odin flies great, but it has some big issues, I didn't like the head dampers and swapped them to KBDD yellow ones - One downside with this setup was that I wasn't able to take of and land on hard ground without some very bad ground resonance -  like main shaft bending bad

I never really got happy with the electric fan. If the cooling was sufficient then I may have been able to live with it, but I prefer an engine driven fan mounted in a fan shroud - Any time.

The crash parts also is expensive. I was used the the Knight 50 prices, but a crash set to the Odin cost roughly 4 times the price and the Knight crash set, and nearly 3 times the price of Align.

For the reasons stated above I returned my Odin, and now I flies a trusty old Raptor 90 SE.

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