Compass (TracX) drive tubes on Black Widow head...? Help needed.

[Jonathan Ott]

Okay, I am going to take a beating from you guys over this, but it is what it is.


I have an RCAerodyne Black Widow head on my Chaos 600.


I know (now) that it is an almost direct copy of the TracX600 head.

I have a problem and need Compass pilots assistance.


The Black Widow head linkage tubes are aluminum, and I understand this is not the best choice ‘cause the stiffness can detract from the flapping of the blades. Additionally, the tubes are too long for use on the Chaos 600, as it is an ESP derivative. The tubes, as they are right now, on my Chaos give ne +7.5° pitch at center collective. The tubes are approximately 46mm long.


How long are the TracX600 tubes? My aluminum tubes look to be about 11mm too long, and that is just a SWAG, I’ve not taken anything apart and performed any measurements…pure speculation.


I’m willing to invest in a set of drive tubes from Nankin Hobby (08-0139S or 08-0138x) but need to know which ones to order. Length is not in the description.


Now, before you go into round two of the beating, I know I’m $90 into this head right now. If I invest another $25, I will be at $115 and if I had just saved another $35 I could have purchased a real TracX600 head and would not have a problem (maybe…).

I am a budget flyer that gets to fly maybe 6 times a year. If I burn six packs, I think I am doing great. I have made my bed, now I will sleep in it, but I want to set this machine up with what I have.


Thanks,

Jon

[Ah Clem]

Jon,

Somewhere, in the Compass forums here on HeliFreak, I measured the Delrin Drive tubes and posted the lengths. I will try to measure a set, today. I can tell you that the TracX drive tubes are exactly 5mm longer than the Compass versions (this so that one could directly upgrade from the Align head to the TracX head without having to swap out the main shaft or do other modifications).

If the Delrin Drive Tubes are too long, you can easily trim them.

I don't know if the drive tubes will fit in the Chaos yokes, so I cannot guarantee they will work. This is an upgrade I would attempt, if I were in your position,though.

If memory serves, you have three mounting holes on the Black Widow head, so you should be able to adjust the height, easily to accommodate the length of the drive tubes.

" I could have purchased a real TracX600 head and would not have a problem (maybe…)."

I have a Chaos 600E, equipped with a Compass/TracX head (the machine flies very well):





I am not sure what dampers are in the Black Widow head (I have not examined one up close), but you should, after swapping to the flexible drive tubes, be able to run any firmness of dampers you want (I run either the KBDD EE Royal Blues or the Lime Greens), as the head will no longer be restricted in flapping by the linkage. The ball links on the swashplate end (you will need the Compass ones) should last longer as well (IMHO).

[Ah Clem]

I just found this-please look at post #6 by Barnstormer (he is a wealth of information):

http://67.228.244.248/showthread.php...ht=drive+tubes

He measured the length of the tubes and posted them.

[Jonathan Ott]

Thanks for the link, those measurements are actually longer than what my aluminum ones are, but I can trim derlin. I don't remember how far inset my aluminum tubes are into the knuckle.



I'll get a diameter of my aluminum tubes tonight and post to see if they are the same size as the TracX or Compass tubes.

Thanks,

Jon

[Ah Clem]

What hole in the main rotor block are you using?

There are three, I think, on the Chaos Head.

You do not want to set the head too low, as this can invite boom strikes.

[Jonathan Ott]

In the pic, I have it in the top hole. If I went to the center hole, it was the same problem, only reversed.



I did slide the head up some to zero the pitch out and marked the shaft with a sharpie. I could have the shaft re-drilled at a machine shop, might be cheeper than ordering and modifying new links, and it'll raise the head up some too.

I'll pull one of the links apart to see how far it insets too.

There has to be an easy remedy for this.

Jon

[Jonathan Ott]

Okay, my aluminum link is 50mm long. If I were to trim it, I need to take exactly 5mm off to get the grips at 0° at center collective stick.

I did find that the ball link stud in the bottom of the tube is fairly long and I can turn it out 5mm and still have enough stud in the bottom of the tube for a secure connection.

This is the route I'm going to go right now, untill I can get a set of derlin llinks.

Oh, the aluminum links are 6mm in diameter. If the TracX or Compass links are the same diameter, then I'll be good to go.

If the TracX links are exactly 5mm longer than the Compass links, then the Compass links would be perfect.

I've only found the TracX links...who carries the Compass links?

Thanks,

Jon

[Ah Clem]

Nankin carries the Compass and the TracX links.

[mattox]

Jonathan are you aware that you can adjust the black widow head arm lengths?

[Jonathan Ott]

Mattox, yeah, from the bottom. Chumley pointed that out to me. I made the adjustment and life is good! I'm going to get some jam-nuts to put on the link stud, just to secure any micro slop and peace of mind.

Thanks everyone for your help, here, and on the other sites.

Jon

[mattox]

John I really hope you like that head. People will probably give you crap but it really does fly nice and it has a crisp locked in feeling while your flying!! I have them on my 550 and 600s and ah Clem and vouch for me and my flying. He has seen the BW head beaten on many times

Mattox

[Ah Clem]

John,

Mr. Mattox regularly flies the living daylights out of it at the SoCal fun flies.

Let us know how it flies with the Delrin Drive tubes when you get them!

[Jonathan Ott]

Thanks guys. Ah Clem, could you get me a quick confirmation on the diameter of the derlin drive tubes? My aluminum ones are 6mm.

Thanks,

Jon

[lotus7]

Originally Posted by Jonathan Ott

Thanks for the link, those measurements are actually longer than what my aluminum ones are, but I can trim derlin. I don't remember how far inset my aluminum tubes are into the knuckle.

Jon

Just an aside , the delrin tubes go 5mm into the "yoke" So measuring them like shown in the picture , measures the exposed portion of the tube and not the full length of the tube

[Ah Clem]

Jon,

Sorry to be so slow...

The diameter of the Delrin Drive Tubes is 5.96 mm.

[Jonathan Ott]

Cool, looks like I'll get a set of derlin tubes in the near future.

Thanks again guys!

Jon

[corrosionate]

I use the Black Widow head on my Chaos 600. The length of the tubes is fine as long as my links from bellcranks to swash are adjusted accordingly. Just have to mount the head on the shaft using the bottom hole. Flies great. Leaves almost no room to adjust blade tracking if u want the elevator lever to be 90 degrees, but i got it in the first try, so it'll work. I would someday like to lower the head using shorter tubes though.