Eric Larsons Cyclic mod

[Zilly]

I'm not quite at the point in my flying when I am considerinf doing this mode however I am keen to understand what it involves. He mentions shimming 'pitch link inner swashplate balls' am i righ in thinking these are the two balls that connect via the long rods to the bell mixers?

Will this affect both aileron and elevator cyclic amounts?

z

[DavidH]

Yes it will affect the cyclics, both fore/aft and left/right.

The balls that are extended on the inner ring with shims. Is the ones that the long rods from the bell mixer attach. It is not the balls that the Washout arm attaches.

David

[misio]

So is only tow balls now all four?

[DavidH]

No it is just the two balls on the inner ring that the long rods going to the bell mixer connect.

David

[ChrisLaFollette]

You need two 0113 balls.

http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=MA0113&Category_Code=MA01

And two 0597-1 brass spacers.

http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=MA0597-1&Category_Code=MA055

Put the spacer on the 0113 threaded part and put some red locktite on it and screw it in the swash and tighten it up good. Dont bust it.

Take a dremel and use whatever tip you think will work best for this next step. Probably one of the cut off wheels ground down real small. I shoved a little bit of tiolet paper around the inner ring so the metal shavings wouldnt get in the bearing. If they do just rinse it out with some rubbing alcohol or MEK or something like that.

I try and take the "space" between the two balls off of the inside ball. Its not really that hard just take it easy.

Then cut the antirotation bolt down so its flush or slightly too short to be flush with the inside ring of the swashplate. You wont want the links to hit it in flight, and they will if you dont shorten it. Mine is actually a little undersized which I prefer.

The cyclic is a little crisper and roll rate is noticeably faster on my machine. I definately reccomend it if your engine has the power to pull it and you want more cyclic. I can get about 9 1/2 degrees of cyclic but I only run about 8.


As Eric Larson says about it:

The stock kit is capable of about 6.5 degrees of blade and paddle cyclic deflection. In stock form and at 10 degrees of collective we are doing about 16+ degrees if we pin the sticks. This can be a bit risky in some situations, but will generally not result in a boom strike. How can it? Well say we do a tail slide and pull out inverted backward. We pull full negative pitch and proceed to attempt a kaos maneuver…. This should turn on that big WARNING DANGER WILL ROBINSON sign in you head. If the stars are not aligned or maybe we have a strong head wind we risk the very real possibility of cutting off our tail boom. Why? Well the main blades are stalled and they have now quit flying to some degree. We also have a LOT of impact air pushing them down into the boom. Bernoulli takes a back seat at this point and our friend Newton takes over and the result is impact air forcing the main blades down enough to impact the tail boom.


Have fun. If you dont think you could do it yourself ill do it for free if you provide the parts and the swash. :)

[DavidH]

You need two 0133 balls.

http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=MA0113&Category_Code=MA01

And two 0597-1 brass spacers.

http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=MA0597-1&Category_Code=MA055

Put the spacer on the 0113 threaded part and put some red locktite on it and screw it in the swash and tighten it up good. Dont bust it.



How do you screw 0133 Ball links into the swash plate?

I try and take the "space" between the two balls off of the inside ball. Its not really that hard just take it easy.

Why?

David

[EricLarson]

The stock inner swash balls will work fine. You can add up to about .018 (which is normally 2 thin washers) behind the balls. Use red loctite when you reinstall. There is enough threads left that it will work fine. You also need to shorten the front anti-rotation 3mm bolt some to prevent interference. Also check everything to make sure you are not rubbing anywhere during extreme throws.

What Chris explained will work, but may require you to modify your swash plate some to prevent binding in the extremes.

This should give you 8.5 to 9.0 degrees of cyclic and an improved roll and flip rate.

I am running about 8.5 degrees.

[ChrisLaFollette]

David I made a typo on the part numbers. 0113 is the double ball im talking about. Sorry.

The 0113 balls screw into the threaded hole that the stock balls came out of on the inner ring of the swashplace.....

....the double ball is too long, it will hit the ouside ring of the swash when you try to rotate it. You have to cut it off at the red line (See the pic below).

http://www.helifreak.com/album_mod/upload/c07466b4caa78edc428dc505669e6891.jpg

I did not modify anything else on the swashplate except for the swash guide bolt. Just took the stock balls out and screwed these back into it with the 0597-1 spacers and then cut the balls off. :lol:

[DavidH]

....the double ball is too long, it will hit the ouside ring of the swash when you try to rotate it. You have to cut it off at the red line (See the pic below).


Don't understand why you would go to all that trouble.

Here is the stock ball that comes on the swashplate.
http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=MA0109

Couple of small washers on the above balls that the long rods is connected to is plenty.
These washers work fine.
http://www.ronlund.com/Merchant2/merchant.mv?Screen=PROD&Store_Code=heli&Product_Code=MA0009

Still plenty of threads to screw into the swashplate with one or two of these washers on the threads of the balls. No cutting or grinding required.

David

[kthane]

Where is the fun in that DavidH? :shock:

[ChrisLaFollette]

Oh well. The only way I could get the balls out without busting my alan wrench was to grab them with a pair of pliers and I had the other stuff on hand so just said what the heck and yanked the old ones out and put these new ones on.

Its more weight to turn, it makes it auto better with those two brass bushings on there now. :lol:

[ChrisLaFollette]

Here are some pictures of how my swash looks. Just made my balls longer. :badair:

The silver parts on the black inside ring are from the previous owner flying it with too much cyclic/pitch together and it hitting the washout pins.... I know somebody will ask.


http://www.helifreak.com/album_mod/upload/591e7fbc8b34d6097b18d2ab910ea5ca.jpg

http://www.helifreak.com/album_mod/upload/359839d24f17aba01eb2278ab50cd767.jpg

Sorry about the terrible quality of the pictures. Camera phones suck at taking pictures.

[Xtreme*76]

[quote="EricLarson"]The stock inner swash balls will work fine. You can add up to about .018 (which is normally 2 thin washers) behind the balls. Use red loctite when you reinstall. There is enough threads left that it will work fine. You also need to shorten the front anti-rotation 3mm bolt some to prevent interference.

Hi to all
Please could tell me what you mean to shorten the front anti-rotation 3mm bolt?
Where and How much do I need to shorten it in terms of mm?
Thank you very much
Respectfull regards
G

[capebob]

G,

If you look at your swash plate you will notice that the 3mm bolt that holds the anitrotation bearing protrudes about 1mm into the swash. Simply shorten that bolt about 1mm so that it no longer protrudes into area between the outer and inner swash rings.

Bob

[Xtreme*76]

Dearest Bob
I thought was respectfull that you know my name
G is for Giuseppe
and I want to tell you and all of you
thank you very much
Tonight I'll work on it
and I'll let you know soon
Regards
G

[Gary O]

Like David said, why go to all that trouble for a couple of * of pitch. In stock form mine rolls and flips pretty quick as it is. Is it just to make it faster?

[ChrisLaFollette]

You got it. Gives you more cyclic pitch given the same amount of swashplate throw as before. I didnt really notice it being any more snappy but it is just a TAD but I can really notice the extra cyclic. I got so much I had to turn my AFR down a little, I was getting 9 1/2 degrees without bogging. About 8 is plenty for me.

[megotroulette]

eric was mentioning about boom striking, and how the stock one can do about 6.5 paddle and blade deflection and at 10 degrees gives and increased chance of boom striking at full stick cause you are pulling around 16.5 Degrees if we pin the sticks..

ok, but wouldn't we be increasing that risk by 20 - 30 % by increasing the cyclic. blade deflection with this mod? yeah i just don't understand sorry


Cheers,

[ChrisLaFollette]

Yeah thats why you should never go to full negative and full back elevator. Chop that boom off like a carrot in a guilitine.

I am running 12° pitch +/- and about 8 1/2° of cyclic. At full negative and full aft elevator your pulling over 20 degrees of pitch. :shock: And with a strong motor it gets even worse. Gotta take it easy on the machine and dont get stupid. You can blow any machine up though if you try. I can bang this thing as hard as I want as long as I dont get stupid and it wont blow up.

[megotroulette]

would you recommend this modification to a fury extreme??

so i guess when you start to get into the hard core 3d, and are having this kind of setup you have to be good with collective managment?

Cheers,

[DavidH]

At full negative and full aft elevator your pulling over 20 degrees of pitch. Shocked And with a strong motor it gets even worse.

The blades stall at about 16-17 degs.

Marty,
You can do the mod to any type heli. Ted Schoonard put the mod in the instructions back in the mid 90's when he designed the 0840 rotor head for the Pro.

David

David