Predator Gasser V2 Going Flybarless with Existing Flybar Head

[al_voisine]

(Originally posted on RR but was recommend to post here.)

Predator Gasser V2 Going Flybarless with Existing Flybar Head

I have the Predator Gasser V2 and I am thinking of going flybarless. I probably wouldn't do it if I had to spend the couple hundred on a new head and several more on the electronics.

I have the plastic head. On first looking at it, it looks like it should be simple to convert to flybarless.

The 3mm hole in the arms on the Blade Holders are in line with the center of the main shaft. So there should be no phasing issue. The Washout is already fixed to the Main Shaft with setscrews, so would stay in place.

1. I would remove the Bell Mixer Arm, Flybar Cage and flybar.
2. Take the Stainless Ball from the Bell Mixer Arm and screw it into the blade holders.
3. Adjust the pushrod (might have to make a shorter one).

So what am I missing here?

I'm thinking of using the Align 3GX. I have it on my Trex550 and like it. Others on here have used it on their gassers with good success. Plus I can pick one up on the forums fairly cheaply.

Has anyone done this?

How did it turn out?

Things to look out for?

]Thanks for any help.

Al

[Dennis P]

I have not done it but many have Al.The only thing you have to be sure of is the distance from the center of the mainshaft to the center of the ball on the blade grip as this is the important number to get the geometry correct for the FBL unit.I just also happen to have the 3GX unit for you and it is posted on R/C Canada heli electronics.I do not currently have a Century 700 flybarless built here so I hope someone ban give you the measurment .If not let me know and I will cut open a new Century 700 FBL head package and measure it for you.

[al_voisine]

Dennis

Thanks for the response and the offer. I just bought a 3GX in the classifieds here this afternoon.

I hope someone posts the geometry you mention so that I can make sure I get it right.

AL

[karl k]

I just measured my Century gasser FBL head.
The ball on the grips can be placed at 30, 34 or 38mm from the centre of the main shaft.
I personally use the 34mm spacing and my FBL geometry works out well.

I measured the G30 FB head and found that the place on the grip where the mixers mount is 20mm from the centre of the main shaft. This means that ideally, you will use a ball with a standoff such that the ball will be 14mm from centre of the ball to the mounting surface.

IMHO, this will put a lot of leverage on the threads going into plastic. Because the nature of the forces on the threads in the grip arm have changed from a shear load to a twisting load that is trying to pry out the short threaded portion from the plastic, there may be issues. The damping of the head will have to be addressed as well.

[al_voisine]

Karl

Thank you for checking it out and taking the measurements.

Dennis P. had suggested that I should beware the geometry and you have confirmed it.

Not only is the geometry wrong, but the plastic head makes it impractical to making it work. I also received a PM to that effect from another guru, albeit without the reason why. This explains it.

So if I want to go flybarless, from what I have seen so-far, I have to choose between a Century head @ $200 or the RJX @ $120. Which would people recommend and why?

Does anyone know of a better/cheaper option?


Al

Originally Posted by karl k

I just measured my Century gasser FBL head.
The ball on the grips can be placed at 30, 34 or 38mm from the centre of the main shaft.
I personally use the 34mm spacing and my FBL geometry works out well.

I measured the G30 FB head and found that the place on the grip where the mixers mount is 20mm from the centre of the main shaft. This means that ideally, you will use a ball with a standoff such that the ball will be 14mm from centre of the ball to the mounting surface.

IMHO, this will put a lot of leverage on the threads going into plastic. Because the nature of the forces on the threads in the grip arm have changed from a shear load to a twisting load that is trying to pry out the short threaded portion from the plastic, there may be issues. The damping of the head will have to be addressed as well.

[karl k]

I think the sale is over, but I snagged my Century FBL head from Heli-world when they had it on sale for $145. I'm glad I did. The machining is done really well and the motion of the mechanics is super smooth without any slop. Keep in mind the weight of the heli and choose accordingly. The head on these machines is about the most important part you could point to.

I can't comment on the RJX head as I have no experience with it.

[Dennis P]

Hello Al I never even thought about it having plastic grips as every Predator I seen has had metal .I agree I would be scared of the long standoff ball pulling the threads.The nice thing about the Century FBL head besides it being a very nice head is that it comes with the linkage ect to just hook up to your heli. They fit all the KBDD aftermarket dampers ect also if you want to play with different thing.

[al_voisine]

Bought the Century head and a used 3GX from the HF classifieds. Should be a fun conversion.

Looking forward to it.

Al

[karl k]

Keep us posted.