Pitch settings?

[bleomycin]

Hi again,

I'm attempting to setup the servo throws with the vbar but i have no idea what the recommended maximum pitch for the main blades and tail rotor should be? The manual states to add 5 degrees of torque compensation to the tail blades mechanically, do i still set the +/- pitch the same for the tail in both directions? Thank you very much!

[flyalan]

For mains its a matter of taste. 12 degrees is a good starting point.
You do not actually measure tail pitch.  At 90 degrees on the servo horn you need the tail pitch slider to also be at 90 degrees. This will give you the needed offset in the tail. Set your VBar endpoints to max out tail throw without binding. Endpoints should be pretty close to the same number.
VBar guys chime in here.

Alan


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[steffgiguere]

I agree with the 12 degrees, only if you are comfortable flying. If you are more of a beginner then I would set 9 to 10 degrees. Then when you are more proficient you can adjust it to around 12 degrees.

[Brandon Bartolomucci]

I learned on 11/11 on the main blades and now run 12/12 since I like even numbers. Also agree fully with Alan's statement on tail pitch.


Regards,
Brandon Bartolomucci
Sent from my iPhone

[curmudgeon]

...do i still set the +/- pitch the same for the tail in both directions? Thank you very much!

It is my understanding that traditionally the tail pitch was not measured mainly because (1) using the mechanical extremes of tail travel without binding worked well and (2) there was no good practical way to measure tail pitch.

That may be changing now as several manufacturers are making the tail shaft a little too long, so using the full mechanical tail slider travel could make the tail pitch inefficient and potentially stall.  Also, newer tools like the RC Logger allow for easy measurement of tail blade pitch.

This thread in the VStabi forum http://www.vstabi.info/forum/read.php?26,87742 discusses VBar tail range numbers for tail shafts that may be too long.

This HF thread http://www.helifreak.com/showthread.php?t=450805 goes over setting up the VBar tail using the RC Logger.

This BeastX thread http://www.helifreak.com/showthread.php?t=450805 discusses useful tail pitch ranges.

[bleomycin]

Thank you all for the help, you guys are great! I wasn't able to get my tail servo horn on at exactly 90 (i bought a nicer looking metal horn) and i wasn't able to get any of the futaba horns on at 90 either. Is it alright for me to just setup the tail with 5 degree pitch using my rc logger 2 like the manual says on page 43B, or would that be incorrect?

[RichL]

You should be able to get 90 degrees using the Futaba servo horn.  Every arm on the horn has a slightly different offset, one of them should get you to 90 degrees the trick is to keep rotating the horn until find the right one.  It is important that the servo horn and the tail pitch control arm be at 90 degrees.  With both the servo horn and the tail pitch slider arm at 90 degrees the 5 degree offset is built in.   Metal servo horns are nice but, IMHO they cause more damage in a crash than the plastic horns.  The splines in plastic horns tend to strip out in a hard crash and help to reduce the amount of damage to servo gear train ....... sometimes.

Rich

[Chris Sexton]

You should be able to get 90 degrees using the Futaba servo horn.  Every arm on the horn has a slightly different offset, one of them should get you to 90 degrees the trick is to keep rotating the horn until find the right one.  It is important that the servo horn and the tail pitch control arm be at 90 degrees.  With both the servo horn and the tail pitch slider arm at 90 degrees the 5 degree offset is built in.   Metal servo horns are nice but, IMHO they cause more damage in a crash than the plastic horns.  The splines in plastic horns tend to strip out in a hard crash and help to reduce the amount of damage to servo gear train ....... sometimes.

Rich

+1

Metal horns have caused me issues. I use plastic and carbon when I can.

[flyalan]

Correct me if I am wrong. Is there not a subtrim function in the VBar that will allow some minor corrections to get the servo horn at 90 degrees. I seem to remember that from my VBar days. The Helicommand does.

Alan


Alan Butler
Team Synergy

[curmudgeon]

I wasn't able to get my tail servo horn on at exactly 90

If using the recommended 16mm servo horn (page 14), the outermost hole of the 4-arm Futaba servo horn is the ticket.  Since the Futaba servo spline is 25T and you have 4 arm options, one of the arms should be within 0.9° error.  Incidentally, the Skookum is the only FBL system I have seen that incorporates a tail sub-trim feature.

(i bought a nicer looking metal horn)

I too like shiny metal bling.  However, those metal servo arms are not servo friendly during crashes.

and i wasn't able to get any of the futaba horns on at 90 either.

Let the FBL unit sub-trim pick up the slack.  For those who need to satisfy the OCD and not use any electronic sub-trim, there are 360° rotation servo horns, but they tend to be made of metal.  I have never seen one in person.

Is it alright for me to just setup the tail with 5 degree pitch using my rc logger 2 like the manual says on page 43B, or would that be incorrect?

True except when setting up the SKookum FBL units, Skookum wants 0° tail pitch at neutral.  For most other FBL units, setting up the tail as per page 43B (tail rotor bell crank 90° to tail box) should yield around +5° tail blade pitch.  If you are not going to be flying using rate mode, that +5° is just a reference to verify the adequacy of the tail neutral mechanical setup, as it is hard to objectively measure the "tail rotor bell crank 90° to tail box" other than eyeballing.

[bleomycin]

Correct me if I am wrong. Is there not a subtrim function in the VBar that will allow some minor corrections to get the servo horn at 90 degrees. I seem to remember that from my VBar days. The Helicommand does.

There does not appear to be one for tail, only for cyclics, i've spent hours looking. Unless it is in the "Pro" version of the software, it's definitely not in express. I'll take your advice and switch to a plastic horn, but i'm still curious regardless, let's say i cannot get the horn perfectly at 90 now or sometime in the future on some other heli build for whatever reason. Is it OK to just get it somewhat close and adjust for the correct tail blade offset with the linkage and the rc logger? And for the E5, should the rc logger pitch gauge be reading exactly 5 degrees when the servo horn and pitch slider are at 90?

[Chris Sexton]

Correct me if I am wrong. Is there not a subtrim function in the VBar that will allow some minor corrections to get the servo horn at 90 degrees. I seem to remember that from my VBar days. The Helicommand does.

There does not appear to be one for tail, only for cyclics, i've spent hours looking. Unless it is in the "Pro" version of the software, it's definitely not in express. I'll take your advice and switch to a plastic horn, but i'm still curious regardless, let's say i cannot get the horn perfectly at 90 now or sometime in the future on some other heli build for whatever reason. Is it OK to just get it somewhat close and adjust for the correct tail blade offset with the linkage and the rc logger? And for the E5, should the rc logger pitch gauge be reading exactly 5 degrees when the servo horn and pitch slider are at 90?

For sure no "sub trim" option on the tail in vbar. Vbar cares more about having the tail servo travels within the 80-120 range and as close to even as possible. Get the horn as close as possible to 90. Adjust the tail control rod until the tail bell crank is 90 to the boom then set travels. If the travel difference is off by more than 5-10 I would move the horn one spline reset the tail control rod and try to set travels again.

Setting up the tail can be a pain but it is critical. I have helped diagnose odd tail behavior many times and it almost always comes down to tail setup. When it's not a vib of course.

My tails on synergies are all within 5 of even most within 2. The tail pitch slider allows for good movement either way.

One note, make sure on TT models you are using all of you tail shaft available. On belt models you need to not let the pitch slider get closet than 4mm to 5mm from the tail case. It is possible to stall the tail blades.

If you have any vbar setup issues let me know. I have setup quite a few.

[flyalan]

Thanks for clearing that up Chris. I knew there was a reason I got away from VBars :-)
Just kidding!

Cheers
Alan


Alan Butler
Team Synergy

[curmudgeon]

One note, make sure on TT models you are using all of you tail shaft available. On belt models you need to not let the pitch slider get closet than 4mm to 5mm from the tail case. It is possible to stall the tail blades.

So Chris, I should use as much mechanical tail travel as possible without binding similar to the Align birds?

[Chris Sexton]

One note, make sure on TT models you are using all of you tail shaft available. On belt models you need to not let the pitch slider get closet than 4mm to 5mm from the tail case. It is possible to stall the tail blades.

So Chris, I should use as much mechanical tail travel as possible without binding similar to the Align birds?

On the TT models. Yes. E5 included.  The belted tail box was narrower allowing more of the tail shaft to be exposed.