Building "Faifa 6s"

[Lars Linders]

It's almost finished!













First thing I want to do next, is setting up the Jlog in my DS-16. For now everything runs smooth. I only have to do some finetuning when the blades are here.
The CG is also perfect with the 6s lipo like this!

[trillian]

Looking good!

[Lars Linders]

I've done my best to keep the Srimok as light as possible, so for example I shortened all the servo cables there where possible, added a lighter home made landing gear and took one a light receiver.
Total weight is now 3,5 kg including rx lipo and one 6s lipo, but without canopy and blades.
I think it's really light weight isn't it?

[trillian]

Originally Posted by Lars Linders

I've done my best to keep the Srimok as light as possible, so for example I shortened all the servo cables there where possible, added a lighter home made landing gear and took one a light receiver.
Total weight is now 3,5 kg including rx lipo and one 6s lipo, but without canopy and blades.
I think it's really light weight isn't it?

Yeah that's pretty good. It should be something like just a little over 4kg with blades and canopy. When you consider that some 600 size helis weigh that much, the disc loading will be very low.

Mine weighs 3.42kg with everything except the flight packs. So add two 650 gram 4000mah packs for a 12 cell setup and it's at about 4.7kg. And it feels very light in the air.

[Lars Linders]

Today I finished setting up the srimok. I completely installed the Jlog 2.6gw and after that I worked at the telemetry in the ds16.
For now everything works really nice.

All measurements where done without main blades. I think I have to tune it a little bit when the blades are one it, but for now the flight modes are having a perfect rpm for me. Can't wait to maiden it! Of course rescue mode is also installed.



Low rpm

Idle 1

Idle 2

Autorotation

Page two of telemetry, with a bit more information

[wadders248]

Loving the Jeti... I've been thinking about switching to using Jeti, especially for speed flying, the telemetry info looks great.

[Lars Linders]

Don't think twice, just go Jeti. It's really nice

[Lars Linders]

I'd ordered blades. Unfortunatly they are in backorder for a while. Because of that I've decided to cancel the order and go for another brand.
I've decided to give the asymmetrical Spinbladed a go.

I've got a question about the main and tail blades size, because they are offered in a few different lenghts.

Asymmetrical Main blades are in 690mm and 710mm
Asymmetrical Tail blades are offered in 95mm and 105mm. They have also some 115mm tail blades, but these are black belts...

Which ones should I take?

[wadders248]

Originally Posted by Lars Linders

Don't think twice, just go Jeti. It's really nice

The DS-16 features look amazing, though I think the DS-14 should be enough for me!

[wadders248]

Originally Posted by Lars Linders

I'd ordered blades. Unfortunatly they are in backorder for a while. Because of that I've decided to cancel the order and go for another brand.
I've decided to give the asymmetrical Spinbladed a go.

I've got a question about the main and tail blades size, because they are offered in a few different lenghts.

Asymmetrical Main blades are in 690mm and 710mm
Asymmetrical Tail blades are offered in 95mm and 105mm. They have also some 115mm tail blades, but these are black belts...

Which ones should I take?

It seems that Radix have either gone out of production, or they're not being made at the moment. If you really wanted a set of 710mm FBL Radix I have a spare used set, in very good condition.

Looking at the asymmetrical blades, are you planning to never fly inverted? Why would asymmetrical tail blades be used, surely that would effect left and right piro rates?

The maximum blade size combination the Faifa can use is 710 x 115 and I would recommend using the biggest tail blades you can for low head speed. I keep looking at either adapting a three blade tail hub, or buying the RC Tek three blade setup for the Diabolo and adapting that for the Faifa.

I've always used 710s for low head speed on the Faifa, though not really tried 690s. The distance between main blade grips on the Faifa is a bit shorter than most other helis. For example a set of 690s on a Goblin 700, would have the same disc size as the Faifa with 710s.

[Lars Linders]

I'll think about your offer to buy your spare radix. Thank you for that offer. I'll send you a om for that.

Thank you from your advise about the lenght, I'll definitly go for 710mm.

Why are you asking if a plan to never fly inverted? Isn't it possible to fly inverted with these asymmetrical spinblades?

[wadders248]

Originally Posted by Lars Linders

Why are you asking if a plan to never fly inverted? Isn't it possible to fly inverted with these asymmetrical spinblades?

In my mind using the asymmetrical Spin blades would be like having different amounts of positive and negative pitch? Which even if you're doing low head speed smooth 3D would be annoying!

[Lars Linders]

I'm asking the next question because I don't want to make any mistakes with my Faifa.

The tail mechanics are at the left side of the tail boom. All the helicopters I've build before, had the tail mechanics at the right side .
Can somebody tell me how to set up the tail. Which way does the slider has to move, when the gyro does it's work well when it's correcting the tail?

Do the tail blades has to be set up perfectly neutral when the servo arm is at 0? Or isn't it a problem that the tail slider is a little bit out of the centre, if the servo arm is neutral at 0? It looks like the slider is standard a little bit out of the middle, but if I correct the slider to the middle with the tail rod, than the tail goes further the one way then the other.

Please, can somebody help me giving a good advise with setting up my tail. It's been a while for me setting up a helicopter, and I guess this part isn't in my mind anymore... thanks!

[Lars Linders]

Anybody?

[trillian]

You set it up pretty much the same as you would for any helicopter. On mine when the lever at the front and the servo arm are vertical there is about 3 or 4 degrees of pitch at the tail blades. The idea is that when the servo is centred you have a little bit of pitch that counteracts the torque of the main rotor so that when stopping from a pirouette the stops are close to even in both directions. But I have also been told by some gyro manufacturers that this is not necessary and the blade pitch can be zero when the servo is centred. There may be an optimised way to set all the link angles on the Faifa, so someone with more experience on fine-tuning it will hopefully chime in.

There is more pitch travel in one direction. When the slider moves outward away from the boom the pitch is in the direction that blows air to the right (moving the tail to the left), counteracting the rotor torque. When the tail moves the other direction it is often helped along by the natural rotor torque so not as much pitch is needed.

The Faifa tail has a LOT of pitch range, more than most people need if they run at higher headspeeds but for low headspeeds you'll need that pitch.

I'm using Rail 106 tail blades on mine and find the tail holds pretty well in most moves. Just sometimes in a move that combines fast forward flight and torque changes, like a piro at the top of a big loop, the tail seems to need a little help. But it has never blown out on me.

The Rail blades hold a little better than Radix 105s, I think due to a bit wider chord.

[Lars Linders]

Thanks for youre reaction, it helps me very well understanding the tail. I've got radix 110's at the tail now. I hope it will hold the tail with low rpm.

Which way moves your tail slider, when you pull the tail to you if you are standing left from the tail? So which way does the slider move when it corrects the tail?

[trillian]

Originally Posted by Lars Linders

Thanks for youre reaction, it helps me very well understanding the tail. I've got radix 110's at the tail now. I hope it will hold the tail with low rpm.

Which way moves your tail slider, when you pull the tail to you if you are standing left from the tail? So which way does the slider move when it corrects the tail?

Well, if you stand behind the heli and sharply pull the tail to the left, the slider should move inward, to the right. You should see the slider move to the right if you move the rudder stick left as well (commanding the nose to move left).

The way I always think of it is that the tailrotor is going to blow air in the opposite direction to move the boom, so I always look at which direction it is trying to blow the air. The rudder stick will move the tailrotor to blow air in the SAME direction as you want to move the nose.

[wadders248]

I still like to setup my helis in rate mode so that the pitch on the tail is enough to hold it still in a hover. With the Kasama helis make sure when then servo is centred, that the control rod to the tail bell crank places the crank in the centre of the arc'd cut-out, then any torque compensation is added using the main tail control rod.

[Lars Linders]

Thanks for this information! This is what I Needed.

Wadders248;
What do you mean with arc'd cut-out? I don't understand this

[wadders248]

The area where the tail crank arm goes through to connect to the servo.