head setup and pitch

[tcprogrammer]

I'm getting near the end of the build on my new protos. I carefully measured the link lengths and matched them up according to the manual. Now when setting up the head, I've found that a lot more link adjustment is required to get zero pitch than I expected. I've already put two turns on the links between the swash and servos, and two more turns on each of the links between the swash and the blade grip mixing arms, and I still have negative pitch at center stick.

I am trying to avoid turning out the short links between the flybar cage and the mixing arms as recommended in the Finless build video. Did anyone else encounter this in their build? I'm using JR3517 servos on the cyclic, and dubro arms with the ball at the exact distance recommended in the manual. Thanks in advance guys for your help!

[pwoodyp]

I think the link distances or lengths referenced in the documentation are specific to a specific to certain servos. I mean they should only be used as a starting point, a good place to start if you will and should not be taken as gospel. By the time you get her dialed in for zero pitch it's a pretty standard assumption the link lengths will end being different than what is generally stated in the docs. True for most heli's and probably true for the Protos also

[exige]

I have JR 3517 as well. I just measured all my links and they are all stock except for servos to swash of course. They are at 29.7mm. Using JR heavy duty arms at 17mm.

[tcprogrammer]

Thanks pwoody, yes I did assume that as well. There are a number of folks out there who are using servos other than the S9650 (which the manual measurements were made for) and even some using DS3517 since I have seen posts about these before. I'm hoping someone who has had experience with servos other than S9650 could comment on how much difference they were seeing in terms of adjusting the link lengths, and whether or not they had to adjust the short links.

[tcprogrammer]

thanks exige, this is a great reference. When I get home I'll measure my servo to swash links. I may be way off there. I was just getting a little nervous at the amount of exposed thread as I have been backing these off

[pwoodyp]

Originally Posted by tcprogrammer

I was just getting a little nervous at the amount of exposed thread as I have been backing these off

Which would be the correct approach and the correct thing to worry about !!! So then keeping your links safe then what's it matter. Get yourself ZERo Pitch w/ the best pitch range (mechanically) and don't worry so much about the actual length of the links. I hear ya though it does get a little unnerving when you get to the outer link lengths, so yes keep em safe do make sure there's plenty rod for the links However having put in my big fat nose I can only help ya with the approach or the method that get you there. As to what you will end up with or in actuality the numbers you end with I cannot. That question I leave for those who have had hands on, the more experienced.

PS: Call me w00d, my friends do so can you... HEY that rhymes "My friends do so can you" hahahahaah

[tcprogrammer]

Thanks again everyone. I got it all fixed now. The values for the servo to swash links are very close to yours, exige, thank you! I have the dubro arms and I think that may account for the little bit of difference there. I was able to get it setup without adjusting the short links so I am very happy. Thanks again!

[exige]

Originally Posted by tcprogrammer

Thanks again everyone. I got it all fixed now. The values for the servo to swash links are very close to yours, exige, thank you! I have the dubro arms and I think that may account for the little bit of difference there. I was able to get it setup without adjusting the short links so I am very happy. Thanks again!

NP, glad I could help.