Help with FBL head conversion please. My balls are too small!

[Harbormaster]

Hey guys -- I just got the Tarot 450 head from CNChelicopter.com, but it's all set up for T-Rex 450 4.75mm balls (my measurement), not the 4mm balls on the 400.

How did you guys who have made this conversion deal with this?

It's easy to have B400 ball links (4mm) at one end of the blade links and T-Rex 450 (4.75 mm) at the other, but for the swash driver arms (a.k.a. the "pork chops"), it looks like I'll have to remove the 4 mm balls on the B400 swash and screw in a pair of bigger T-Rex 450 balls that will fit the Tarot links.

Is that what y'all have done?

Thanks for any help and advice you can lend on this!

(Oh, and sighting through the Tarot head's bolt hole, it looks like, sure enough, I'm gonna have to file off about 1 mm from the main shaft to get it to fit all the way in. The main shaft almost fits in the Tarot head, but not not quite.)

[Luvmyhelis]

Exactly! The smaller eflite balls are dangerously small. The direct fbl linkage needs larger balls and a more solid secure link and ball size to work properly. The smaller balls and links are not intended to handle the direct swash to grip stresses. I ended up using an Hdx/B400 sonix style swash with raised center. Before this I used an upgraded Sonix swash and had to file down the link ends when I used the larger swash balls. But again it was dangerous so I finally had to abandon it.

Like you said you can switch link ends to match the balls but it simply isn't safe. I ran the eflite size balls on my Sk720fbl 6s thread mod, and noticed the links popped off anytime I really ran large swash angles. Not good. Plus with the close ball to swash clearance when I used larger trex sized balls I had to clearance the link ends and they still popped off also.

[Harbormaster]

Thank LMH. You do mod man for sure. Looks like trying to stay with the stock swash is unwise.

Can you tell me the exact replacement swash you'd recommend? Seems like an HDX 450 something, but I'm bewildered by all the options!

Thanks!

[InFocus]

I disagree with Luvmyheli's opinion, and clearly Blade does as well.

The fix for the OP situation is exactly has he described. replace 2 of the balls with the larger Trex balls. Many of us have done this with our B450 conversions using the Tarot head.

The B450 ball size is just fine for FBL. The Blade 450X is using the same size ball as it did for the B450 3d, which is the same as the B400.

I don't know about the b400 swash, as it is a different part number than the B450 3d swash, but I'm not sure what is different about it.

If your popping balls off at extreme swash angles it is more likely because there was binding somewhere. I'm not sure why the SK720fbl would do that, but I have no experience with that FBL unit. Also, running a 6S setup is also very different than the normal 3s. Maybe the additional weight and power of the 6s does put more stress on everything as well.

If you run the recommended 12 degrees pitch / 8 degrees cyclic, with a normal 3S setup as is found with the Blade 400, 450, 450x, it is not dangerous or unsafe at all.

[Luvmyhelis]

Saying eflite and I disagree with each other is simply not the case here and an interesting accusation. The B450 swash is a different animal. I believe it already has a raised center over the B400 swash? If so that would present a good solution. I may head down to the local hs today and take a peek just to satisfly my curiosity. As I did when the B450 first came out. We did a complete parts compare. I admit I didn't look at the swash closely enough to remember.


And yes the links were binding. The very minute I put on the larger swash balls. ScottS had the identically same problem. I may fly harder? Who knows, but running those small balls with a direct link to the grips is just not real safe. When you look at the fbl kits, all of them have upsized links and link ends for a reason. I (of coarse) tried to mod around it and it wasn't pretty.

Not disagreeing. Just thinking your 450 swash is a different animal. The progression was eflite looking forward to fbl. The swash had to be modded.

The other option is to abandon the Rjx, HK, and a few other 2:1 swash to grip ratio fbl heads and go with a narrower grip head that offers 1:1. Then the swash angles stay relatively mild. No big swash angles. No binding. But the beastx doesn't do well with those heads.

Yes, the B450 swash already has the raised head center. Here is a pic from HeliDirect

[InFocus]

My mistake then. I misread your post as indicating that the size of the ball itself is not adequate.

I thought that the size of the balls used on the B400 swash were the same size as that on the B450 and B450x.

If the size of ball on the 450X is smaller in diameter than the Align 450 swash ball size, although the thread size is the same, so they can be interchanged.

I did not realize the real issue was the swash itself. Apologies if my post confused the issue..

[Luvmyhelis]

Well of coarse eflite stepped out of the accepted mold for their 3d stuff. Everyone does use larger balls and links except them it appears. Even in kits. But still, there was simply no room for the larger balls on the 400 swash.

[1157]

What is meant by "raised head center?". I'm looking at two swashes; a 400 and a 450. I don't see a difference in design.

[Luvmyhelis]

The center hub on the B450 swash is raised, significantly. The balls sit higher up from the lower plate and have more room to fit the links. This is a pick of the stock config B400 swash from Sonix when I fitted my original head long ago. Notice I had to undercut the links just to get any swash movement at all. This weakens them. Since a pic is worth a thousand words this ought to do. Pic 1 is the stock config eflite b400 swash, pic 2 is the aftermarket version with raised center hub. Notice the difference? It is almost exactly the same as the pic of the B450 swash. Scroll back and forth a few times inbetween the two. There is almost a full 2mm difference in the mounting height of the center hub to grip balls.

I also had to seriously cut the elbows down on the swash ball lower servo link arms. They also bound up as you can see in pic 1. A stock swash just doesn't cut it. I later got around this by using balls with longer seating pillars. All my helis will turn over on a dime.

[1157]

Luvmyhelis,

The photos helped a lot. I think I understand now. I think I'll leave that darn flybar on there. It seems to be easier to buy a 450X. All my other helis are FBL.

[Luvmyhelis]

Originally Posted by 1157

Luvmyhelis,

The photos helped a lot. I think I understand now. I think I'll leave that darn flybar on there. It seems to be easier to buy a 450X. All my other helis are FBL.

Haha, no problem. No mod seems to be easy by itself. Seems like one thing always needs another. But going fbl on the B is highly worth it. It changes the entire experience and actually makes setup much easier when finished. I myself had to learn the hard way, even when ScottS posted what I just did (without the pics) I chose to try and ignore it.

Wasn't one of my brightest moments.

[Harbormaster]

I have another question for those who switched to the Tarot head. I measure only 38 mm between the swash balls and the blade grip balls with the blades at neutral pitch. That means it's impossible to use the cool turnbuckle linkages that came with the Tarot head because they're too long.

My question is this: what did you use for the linkage between the swash and the blade grips?

Thanks!

Edit: OK, I just measured it again and it's more like 48 mm. (It's late.) Maybe I can get the turnbuckles to work if I screw the links all the way down. I'm still curious to know what others used. Thanks.

[nbisme]

Originally Posted by Harbormaster

My question is this: what did you use for the linkage between the swash and the blade grips?

I'm having this same issue (albeit with a 450 3D). Using this tarot fbl head: http://www.cnchelicopter.com/servlet...-3-Axis/Detail. The head says "nitro version" or something like that on the top pin. Lots of positive pitch that I can't reduce any further.
I'm anxiously awaiting an expert to chime in. Thanks x2.

[fishboy77]

Woops I posted this in the wrong thread... this is about the Tarot head.

[Harbormaster]

Just FYI, the clone FBL heads are back in stock at HobbyKing:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=12941

[fishboy77]

Originally Posted by Harbormaster

Just FYI, the clone FBL heads are back in stock at HobbyKing:
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=12941

Thanks for the heads up I might have to give that a try. I don't see any washout arms or arms for the blade grips in that picture. Does anyone know whether or not they are included?

[Luvmyhelis]

Originally Posted by fishboy77

Thanks for the heads up I might have to give that a try. I don't see any washout arms or arms for the blade grips in that picture. Does anyone know whether or not they are included?

Yes, all you will need are the dampeners and pro 51mm feathering shaft. Hmm, thinking about ordering another few backups as spares.

[fishboy77]

OK, thanks!

[Harbormaster]

Originally Posted by Harbormaster

Maybe I can get the turnbuckles to work if I screw the links all the way down. I'm still curious to know what others used. Thanks.

Update: I think I could have got the 38mm long Tarot turnbuckle links to work except the threads on one of them were kind of messed up. (The workmanship on the turnbuckles overall was poor. Too bad--I love turnbuckle links.)

I ended up using two Align "Linkage Rod D"s, which are 32 mm long. They are a much better fit for me than the 6 mm longer Tarot turnbuckles. (You know you have a heli addiction problem when you drive 20 miles for better fitting linkages.)

[Luvmyhelis]

Believe it or not it is the little things like that that stretch a build time out as you run into them. Just think what might have happened if you had a violent pos pitch change in flight and that cheesy link pulled out of the grip end. Oddly I have 3 sets of turnbuckle links I bought here off the f/s section that were worthless. The threads aren't pronounced enough to give a positive connection. I saw the tarots late last night when I ordered some new grips in to try. Glad now I didn't order those links.
Thanks!