How to setup pitch using 'protractor' method?

[pck]

Hi guys, i searched this forum but could not really find what i am looking for.

Can someone please teach me how to use the protractor method to setup the pitch for the EP200? I have never done that before and i have been using the pitch gauge for my other 450 sized helis.

The manual isn't very clear either. It instructs to fold the main blades 90 degrees and and parallel to the flybar. But the next diagram shows a 'floating' protractor with the pitch between +-13 degrees settings.

My question are how do you hold the protractor when setting the pitch? Do you rest the protractor on anything or any parts of the heli while setting the pitch? How do you keep the base of the protractor parallel to the ground? Any special tools to use apart from the protractor alone? :thinking Do i need 13 degrees pos/neg pitch for 3D or is 11 degrees sufficient?

Sorry for all the questions. This is my first 200-sized heli... and everything just seemed so.... small... :o

Thanks in advance for your advice.

[psindrup]

At center stick, and your servo arms level/90 degrees, adjust the links so you have 7mm of space between the bottom of the swash plate and the top of the frame - and you are good to go.

Peter

[cyeung]

may be u can simply follow the manul's suggested lengths for longest, middle and shortest distance between the swashplate and the frame to find out the highest pitch and lowest pitch... it works for me

[pck]

Hi guys, thanks for the replies so far.

so you guys don't use the protractor at all? Just go according to the distances between bottom of swash and top of frame as a guide?

What about pitch angle? Is 11 degrees sufficient or do i need 13 degrees?

[Buzzkill]

Greybeard is the protractor king better let him explain.

[pck]

ok, i am waiting for the 'King's arrival... :noteworthy

[knucklesdragon]

What about pitch angle? Is 11 degrees sufficient or do i need 13 degrees?

11 degrees should be sufficient... I am running about 11 or 12 and at full collective with wooden blades the motor bogs pretty bad... I think too much more pitch and and it would really bog bad. (my throttle curve is 100, 90, 100)

As for using a protractor for setting pitch I will try to explain (if I was home I would take a photo or 2)


Base of protractor needs to be level with the flybar. (I eyeball it)
There is a hole in my protractor in the center of the 0 deg line. Basically if you close one eye and look through the hole of the protractor you should be looking straight through your feathering shaft (if your blade root was not in the way... but it is) :thumbup:

I hope this helps??? if you still have questions later I will try to take a photo.

[Gr4yb3ard]

Knuckles has it pretty well explained.

Once you've done this, you can read the angle by setting the "0" of the protractor on one blade, and read the resultant total angle on the other.

Divide by two, and you get the pitch.

Using the measurements supplied in the manual works pretty darn close though.

One note, be careful when you've got your blades folded or moving them during this, you can put some stress in the head system.

As far a <King?>, okay, I see now, I need to cut up more and p*ss more people off, if it's got to this level.

Gr4yb3ard
"....happily deposed... ....YO! SERVING WENCH!!!..."

[pck]

Thanks Knuckles and Gr4yb3ard for your explanations. But some pictures (or better still, a video clip) would really be great for me. I still have a couple of questions:

1) Do you put the protractor "behind' the heli or in front while doing the pitch adjustments?
2) Do you measure the pitch angle using the 'bottom' of the blades? or 'top' of the blade?
3) Gr4yb3ard, you said 'Divide by two, and you get the pitch'. What do you really mean by this?

Sorry guys, if the questions sounded silly. I just want to make sure i get it right.

Thanks guys!

[knucklesdragon]

Attached are a couple of crappy paint drawings to hopefully show you how to do it. I am at work so paint is all I have for illustration

1. I hold the protractor in front of the helicopter.

2. I use the center of the blade to measure the pitch straight through the blade chord (chord - the straight line distance joining the leading and trailing edges of an airfoil)
If you have your blades oriented correctly for this measurement, you should be looking straight on at a flat blade. Attachment 1

3. Hopefully attachment 2 helps you understand this.

[Gr4yb3ard]

1. Protractor in front of heli, on axis with the feathering shaft, or "spindle". Put the vertex (usually a little hole) of the protractor on the center of the grip. Sight towards the blades.

2. One blade will be up, at it's individual pitch angle, the other will go down the same amount (or something is bent ;-). Thus, you take the total angle and divide by two to get the pitch of the individual, or should I say, average blade. This is what makes the technique so cool, the angles and amounts are exaggerated, which makes it more precise than using a $50 pitch gauge. (I've got one gathering dust if you'd like to buy it ;-)

3. The blades should be pretty much flat from this viewpoint. To be extremely precise, measure from leading edge to leading edge.

Don't worry too much about this, if you just get it reasonably close, with this technique, you'll be okay. Double check your swash travel against the measurements listed in the manual though, as a reality check.

Be sure that your swash is level with the servo arms all at 90degrees with center stick.
This should be done using spare servo arms (trial fit) and as little subtrim as possible. Then check for collective mix/drift/changes as the swash moves, using a tiny bubble level.

Again, I cannot stress to highly the value of Lord Finless's videos on CCPM 1&2!!

Lots of this stuff is that simple geometry that I snoozed through in high school, comes in handy now... ;-) I kidded about the chopsticks and such, but I'd bet I can set up a heli now with nothing I could not buy at Walmart, no kidding.

Gr4yb3ard
"...if 'ye get frusterated, PM me on this stuff..."

[pck]

Knuckles and Gr4yb3ard,

Thank you both for the detail explanations and pictures. The pictures really speak a thousand words and the explanations makes it even more clearer now!

Yes, i have watched Finless CCPM setup 1 and 2. And that's the method i have been using to setup my 450 sized helis. But the protractor method instead of using of a pitch gauge is really new to me. I wonder if this method is as good when applied to a 450sized helis...

Thanks guys! As soon as i land back in Singapore (currently on business trip!), i will try out this method over the weekend.

Cheers! :)

[Buzzkill]

Pck,

The protractor will work on any heli. As with a pitch guage, you have to make sure to have everything "lined up" right to get accuracy. Wouldn't it be great if they made a "all-in-one" flybar leveler/swash leveler/pitch guage ? Guess I'm just lazy ;)