RunRyder - Inner hole on EVO 50 Grips?

rrTV-PHOTO

New HD TV

HOME rrTV-PHOTO GALLERIES MY GALLERY HELP-FAQ

myHOME PM pmRR MEMBERS 321 ONLINE 42 EVENTS SEARCH REGISTER START HERE

2 pages [ << < 1 ( 2 ) > >> ]

2491 views

POST REPLY

Ron’s HeliProz South	.	Century Helicopter	.	MTA Hobbies
	.		.

HIROBO Freya - Sceadu - Shuttle > Inner hole on EVO 50 Grips?

hhart
Senior Heliman
Location: San Jose, CA

Andy,

that's alot of pitch.... I'll follow up your finding after testing the TREX600 head.

-hhart

05-17-2007 Over year old.

DS 8717
rrProfessor
Location: Here wishing i was somewhere else

Moved the balls to the inner hole on the blade grips and installed a longer flybar. It increased the collective to 13 and 13 and cylic throw 7 and 7. With the longer bar,the hover is very good and the cyclic is definately faster,FFF is very good with no pitching at all.This is with Radix blades which arent the fastest but are still pretty fast and very good in FFF.DOUG

05-22-2007 Over year old.

KevinB
Senior Heliman
Location: Saskatoon, Saskatchewan, Canada

sorry this is a little long, but.......... racingstripe ? .........

Racingstripe or anybody, do you know the dimensions of the Avant mixing arm you posted the pic of ? I emailed Carbon Extreme but haven't heard anything back. Just the distance in mm from the center of the bearing to the innermost and outermost hole would be great !

The flybar ratio is the real key to a fast flip/roll rate. I was trying for some time to get more cyclic throw out of my SD-G head to increase the rate on my evo50. I was using the high mobility hole on the flybar carrier, and moving inward from the bearing in the mixing arm...using the 2nd of the 4 holes for the link to the grips, and the 3rd hole for the link to the swash, and using the inner holes on the blades grips. This was ok...but NO WHERE NEAR as fun as the evo was when I threw my Fury's rotor head on it. I could only get about 6 degrees of cyclic on the SD-G head in this setup (without any control binding) and about 8 on the Fury head...and I thought that was the problem.

Recently I tried using a head consisting of the SD-G but with JR Venture flybar carrier/mixing arms. With this head I could get 8-9 degrees of cyclic and I thought I was set. However, when I test flew it, the rate was HORRIBLY SLOW. This setup had also increased the flybar's authority, and that overpowered any gains from being able to run 3 degrees more cyclic.

I saw this thread and made up some temporary mixing arms. On these the swash link was the same distance as hole #4 on the SD-G mixing arm, but the link to the blade grips(still using the inner hole on the grips) was 7mm toward the bearing from hole #4. This gave me the same flybar ratio as my Fury head ( full flybar deflection stop to stop changes the main blades by ~ 10 degrees, the original setup on my SD-G head gave ~22 degrees! ). And guess what ? It flew just like the Fury head too ! It will now flip and roll FAST. I was worried it would become pitchy in FFF, but it was just as stable as before too.

Once I have made some more permanent mixing arms out of some leftover washout arms, I'll post some pics.

Just one more note...anyone trying the above should be running CX or Infinivation dampeners in your head and carbon blades. If not, you're beggin for a boomstrike as this is a very responsive setup.

KevinB

05-24-2007 Over year old.

tjongkristian
Senior Heliman
Location: Jakarta, INDONESIA

KevinB,
Can you post a picture of your setup? Thanks.

05-24-2007 Over year old.

racingstripe
Veteran
Location: Sacramento, CA

KevinB,

Quote
Racingstripe or anybody, do you know the dimensions of the Avant mixing arm you posted the pic of ?

I didn't get around to ordering those. I'm a slacker... I still need to test out those modified FFZ-III mixer arms. Which BTW, will give a .51 to 1 flybar ratio in the mobility hole on the flybar carrier. By using the inner hole on the blade holder will yield:
.66 : 1 - seesaw inner hole, aka 'high mobility'
.71 : 1 - seesaw outer hole, aka 'auto stability'

I did get around to doing the bench set up... To reduce collective pitch I used the inner hole on the SD-G T-lever & outer hole on the HPM pitch control arm. I used ATV to reduce cyclic pitch down to 7.

andy-

Proofread carefully to see if you any words out.

05-24-2007 Over year old.

HOMEPAGE

KevinB
Senior Heliman
Location: Saskatoon, Saskatchewan, Canada

mixing arm.....

Here's a pic of the mixing arm I will be using. I haven't flown it yet, but it is very close to what my test arms were, so results should be the same.

There is 6mm between the two holes. The arm is an SD-G washout arm with the short end cut off completely and the last hole cut off the long end. That was needed to clear the pivot point of the flybar carrier. The ball in the existing 3mm hole is a MinAir short ball. It just needs to be short enough that the flybar cage won't contact it when deflected. The hole for the blade grip ball I had to drill and tap to 2mm.

Because the holes are so close, you have to put one ball on either side of the arm, otherwise they will bind on each other. This puts the link to the swash at a bit of an angle which is not ideal....but the linkages run free with no binding and it's so much quicker, I don't care

. You can't run the blade grip link to the trailing side of the mixing arm because it would interfere with the flybar cage.

With the current setup I can get +- 12 degrees collective and 10 degrees of cyclic IN EACH DIRECTION with no binding whatsoever in any combination of stick inputs. (note: I'm using a cyclic ring on my Tx) It would probably do more but even with this, you need to be careful with your stick inputs or you can bog the engine real quick pulling over 20 degrees of pitch on the main blades ! Measuring the flybar deflection vs the blade deflection gives me a flybar ratio of approx. 0.45:1 .

I'll give a final report after this weekend as I hope to get some flying in on the evo to see what it can do with it's new found agility !

05-25-2007 Over year old.

racingstripe
Veteran
Location: Sacramento, CA

KevinB,

I think you're better off using the outer hole on the blade grip. You'll get even less flybar ratio than where you're at now. It may cost a degree in cyclic, but the net response will be the same given the lower flybar ratio. Just a thought... obviously, stick with what works.

I was finally able to get a couple of test flights in today. The cyclic response was noticeably faster over the stock setup. The nice thing about the mod is the heli still handles like a Sceadu, just faster cyclics. I was surprised that the heli was not pitchy in FFF, still well behaved.

I'm using SAB 620mm main blades, apx 147 grams. Stock paddles, no weights. FFZ-III mixer arms in the stability hole on the flybar carrier. SD-G center hub, stock dampeners.

I have some video locked away in the camera... I'll post when I have a chance.

andy-

Proofread carefully to see if you any words out.

05-25-2007 Over year old.

HOMEPAGE

KevinB
Senior Heliman
Location: Saskatoon, Saskatchewan, Canada

Hi Andy.

I did try (on the bench) using the outer grip hole and could still get close to the same travels. The only concern I had with it was that at lowest pitch, full cyclic deflection, and full flybar tilt, the mixing arm came uncomfortably close to over-centering and locking the swash into that position. I think .45 ratio is going to be ok. Any lower and it might start losing that locked-in evo feel I love.

If you are trying for more mobility, why are you using the stability hole in the flybar carrier ? That just increases your flybar ratio doesn't it ?

I'm using Infinivation dampeners, 600mm V-blades, stock paddles-no weights.

Kevin

05-25-2007 Over year old.

racingstripe
Veteran
Location: Sacramento, CA

Quote
If you are trying for more mobility, why are you using the stability hole in the flybar carrier ? That just increases your flybar ratio doesn't it ?

Yes, I figured the stability hole on the flybar carrier would yield a flybar ratio of about .55 to 1 vice .51 to 1 in the mobility position.

I was worried about cutting the tail boom off.

I'll have to measure the stock bell mixer again... but I think the the ratio is around .75 to 1 (mobility), .8 to 1 (stability).

To be honest, I think the cyclic response is fast enough on a stock Sceadu. Lately I've been spending a lot of time getting backward inverted circuits down in each direction, hurricanes, etc. which doesn't need a great deal of response. However, I have to admit it was a lot of fun bangin the Sceadu around doing tic-tocs and the like.

andy-

Proofread carefully to see if you any words out.

05-25-2007 Over year old.

HOMEPAGE

tjongkristian
Senior Heliman
Location: Jakarta, INDONESIA

Tried the inner hole today. The roll and flip were definitely faster. But, somehow, regular hover felt "a bit quirky." I could not describe the quirkiness. Will try again on sunday.

05-26-2007 Over year old.

KevinB
Senior Heliman
Location: Saskatoon, Saskatchewan, Canada

tjongkristian,

If you JUST moved the blade grip link ( and everything else is set as per the manual), then it will feel funny. It will also fly INTO wind by itself, and may try to dive in FFF. To run the inner grip hole you need to also move the ball on the other end of the grip link to the inner hole( away from the bearing ). This is done to help balance out the increased authority the flybar got from moving the ball on the grip.

FIRST IMPRESSIONS ON THE NEW MIXING ARMS......
I flew my evo last night and this morning. It was FUN ! It rolled so fast, it was kinda scary until I got used to it. It flips just as quick too. You really have to be careful with your stick inputs cause you can bog it really quick also. I put on some V-paddles for today to see what they would do. They added a little stability, but slowed down the rate. Not sure which way I like better. I'll fly like this for a while and see.

05-27-2007 Over year old.

bigblock
Senior Heliman
Location: sweden

Interesting...

05-27-2007 Over year old.

KevinB
Senior Heliman
Location: Saskatoon, Saskatchewan, Canada

a success !

Well, it appears I LIKE scary fast

The stock evo paddles will go back on and that is how I will fly from here on.

Time to burn some fuel !

KevinB

05-28-2007 Over year old.

DS 8717
rrProfessor
Location: Here wishing i was somewhere else

Question # 811
Dear Curtis
Is there any bad side of using low flybar ratio rotor system?
Thanks and regards.
- Kevin
,

Answer
If you go too low the model starts to act like a Flybarless system and has instability problems in forward flight. Most available flybar ratios do not get anywhere near that low.

Another limit with low flybar ratios is the model is not as quick around center. But the standard lower ratios often track better in forward flight.

05-28-2007 Over year old.

KevinB
Senior Heliman
Location: Saskatoon, Saskatchewan, Canada

Mr10X

That wasn't me on Curtis' website. The answer doesn't state what "that low" is either. I guess a flybarless head would have a flybar ratio of 0 seeing that there isn't one..... I'm nowhere near that.

I did some measurements for comparison.....

Stock SD-G head using inner grip holes, high mobility hole on the flybar carrier, and using holes 2 and 3 on the mixing arms:
Mainblade change: 22 deg with 24 deg of Flybar tilt: = 0.92 ratio

Fury Extreme head at highest mobility:
Mainblade change: 10 deg with 24 deg of Flybar tilt: = 0.42 ratio

SD-G head modified as in pic I posted earlier:
Mainblade change: 12 deg with 24 deg of Flybar tilt: = 0.50 ratio

During my second day of testing, the wind was 28km/h gusting to 40km/h and the evo was stable in FFF.

I'm also running 40% expo on cyclic to calm it down around center stick....so "not as quick around center" is definitely not a problem either.

I could see if you went even lower with the ratio, as you approached a 0 ratio there would be a point you'd lose the initial 'kick' provided by the flybar.

I'm not certain my terminology is correct ? I've always understood the higher the flybar ratio, the more control the flybar has...aka: the more stable the setup is. I'm not sure I'm giving 'flybar ratio'.....or some other ratio in my numbers above ?? 'Main blades to flybar ratio' perhaps ??? Whatever......0.50 works great if you like an agile setup. No need to go lower.

KevinB

05-29-2007 Over year old.

KevinB
Senior Heliman
Location: Saskatoon, Saskatchewan, Canada

a follow-up

I ended up going back to using V-paddles. They slow the rate down a little, but are a little more consistent for cyclic reaction when flying in wind. I found the stock paddles got a little pitchy in FFF when flying in wind > 25 km/h.

The evo is a blast with the 0.5:1 ratio. Quick on the sticks but still evo-stable in FFF and hover. Any evo I build from here on will have this mod.

KevinB

06-28-2007 Over year old.

hhart
Senior Heliman
Location: San Jose, CA

Guys,

Evo50 with Trex600 head and ccpm are awesome. Cyclic rate is faster than the original evo50 head. I'll stick with this setup for a while.

-hhart

06-28-2007 Over year old.

Fit
Senior Heliman
Location: Temasek

Evo 90 mixing arms

I tried racingstripe's setup of using the Evo 90 mixing arms. Cyclics and collective pitch both went off the scale! The pitch range is nuts with this setup.

I dialled down the pitch to +-10 and the cyclics to +-8. Its definitely faster, but my TGD blades broke and am now on GCTs/Mavrikk blades.

I dont like the GCTs at all, even before the mixing arm mod they bog way too easily. I cant even complete a proper tic toc as the engine bogged a lot. With the TGD's I can do them with ease with no bogging even though they are slower.

So with the GCT and mod combi, they are really quick on the cyclics but due to the bogging i cant do much either other than flying around and showing off the poppiness of the GCTs and the quickness of the roll rates.

So at the moment, i dont really have a good feel of the mod and how I like it due to the blade change.

Will try better or the exact same TGD blades and get back with my findings of the modified evo 90 mixing arms.

Hornet X3D : GY401, 9CHP, AXI, MS116+____Evo 50, 50SXH

07-11-2007 Over year old.

HOMEPAGE

2 pages [ << < 1 ( 2 ) > >> ]

2491 views

POST REPLY

Model Rectifier Corp	.	PowerHelis	.	JR-Spektrum
	.		.

HIROBO Freya - Sceadu - Shuttle > Inner hole on EVO 50 Grips?

UPDATE SCREEN PRINT TOPIC

Advertisers

Subscribe to This Topic