Ben Diss

My Feedback: (23)

Ball links or clevises? Please tell me you didn't use ball links with plastic servo arms.

Miloh

Hay Ben:

Ball links with plastic servo arms.......OOPS!!!!!!!!! DP 540T EDGE with Saito 2.20
This thing was absolutely destroyed in the air!! It just went limp and made its way to the ground. What a racket!!!! hope to never hear it again. 8611s and Alum. servo arms all around for the new composite 2x2 extra on the way.

Miloh.

cstevec

My Feedback: (1)

I have been doing this for a long time but I'm always up for learning something new. Whats the problem with using ball links with nylon servo arms? Dubro has been making (and modelers have been using) ball links for years. Aluminum servo arms are a relatively new thing. So what I'm wondering is are the new plastic (nylon) servo arms somehow not as good as the older ones?

I'm wondering because I just replaced the hardware on my 10 year old Carden because it was showing signs of wear. All it has ever had on it was Dubro heavy duty Servo arms (nylon) and Dubro ball links. If there is a problem with this stuff, I'd like to know.

Miloh

Cstevec:

I didn;t know it was a problem either but I lost a nice bird last weekend when that exact setup gave way. I've had a few setup this way and never had any trouble with it. I'm not going to risk it again. as a matter of fact I don't plan to use ball links anymore on any kind of servo arms.

Miloh.

blcargen

Guys, ball links and plastic servo horns are not the best way to setup a control linkage, unless you use the glass impacted heavy duty horns. The horns that come standard with servos are not strong enough to handel the loads that larger planes can put on them. If setup correctly they work very well. I did use glass impacted horns on my Extra 260 with 4-40 heavy duty ball links.

blcargen

Miloh,
Sorry about your crash! The aftermath looks very simular to mine. I know how you feel.

P-51B

My Feedback: (5)

Isn't this rather independent of using ball links with them?

Is the issue that the standard ones are not torsionally stiff enough, so they twist when the load is applied from the offset of the ball link (ie, a lever arm)??

Miloh

The lever action is why I plan to discontinue the use of the ball links. I heard they were better but never understood how by hanging out there off line with the lever are.

Miloh.

cap_232_2000

Hello; Robert Raudenbush here of Raudenbush Synthetics, (Joplin, MO). This Friday, (July 15th) I took my brand new H9 Extra 260 out for the first day. I had a brand new DA-50 and a brand new JR-9303 to boot. I was using Fataba servos with Duralite Batteries. Every product in my plane was new and purchased specifically for this aircraft. First Flight went very well although I thought I might have seen a little shimmy on one of the ailerons when the plane past me. Forth Flight, I was coming in from the left down the runway at about 35 to 40 percent throttle and pulled to vertical at show-center. As I was at the top, I pushed over for a Humpty and cut the power to idle. On the downline I did a half roll, (Canopy toward me), that's when it all went to hell. Massive Flutter hit both ailerons at the same time and before it quit, then transfered into the wingcores. Fortunately, I was able to get the nose alittle up right before it went in and I think my DA-50 is ok. The rest is a total loss. I am calling Horizon tomorrow to see if I did something wrong. [email protected]

Miloh

How were your controll links set up Robert? Did anything in the link break? did the servos strip? horn come loose? anything you can see?

Miloh.

cap_232_2000

Used all the linkage provided in the kit, but I purchased the Quick Link (Turn-Buckles) to connect my arms to the surfaces. I also purchased Futaba anodized aluminum arms for my servos. All of that held well. But when I got to the crash site, both gear trains in my Futaba 9202's were stripped. The only thing I can think is that this servo just didn't have enough holding power around center. It does not have metal gears. But it did have plenty of torque according to the manufacturer. I need to leave my computer and get to the field. If you'd like to chat more, feel free to give me a call toll free. 1-888-747-0728 I am really confused about where the week link in my setup was. If you do call, give me a couple of minutes to log off. Have a great day and hopefully not as expensive of one as I had Friday; (Robert)

Miloh

Waxing the car right now, Just came in for a drink. I'll holler at ya in a bit.

Miloh.

aviti

My Feedback: (54)

Despite what any manufacturer would say, I would recommend metal gear servos on ailerons for a plane this size, especially with just one aileron servo per side. In fact, JR 8611's would be my choice all around for this plane. The Hitec guys might say 5645's or 5945's. Hope you figure out what happened and maybe Horizon will help you out.

Miloh

I'm leaning toward flutter due to overworked and stripped gears in the servos. When my DP540 went in both the aileron servos had no gear left that I could feel. I could just spin the control arms all the way around. It's sad to loose one this way.
Did H9 recommend the servos you used? If so you might get a little bit of credit toward another kit. You can at least try.
BTW Horizon gave me $100 off my second 1/4 GP Patty that went in due to a melted battery plug. I had my LHS owner call and give them the skinny on the failure as he could see what happened. They did not hesitate to accommodate.

Miloh.

cap_232_2000

Hey !!! Monday morning here and I'm going to call Horizon today. The only thing that I noticed abit out of the ordinary was that the plane seemed to need and unusaul amount of right aileron and right rudder trim to fly straight and level at Half Throttle.

cap_232_2000

Just talked to Horizon about my crash. They are sending me a shipping label and wish for me to send it back to them for inspection. They seemed very apologetic about my situation so far. Bye the way, did your H9 260 seem to need an excessive amount of right aileron and rudder trim to get it to fly straight and level when trimmed to half throttle ??? They told me me they wouldn't leave me hanging, (I sure hope not) Don't know if I told you, but if you'd like to compare notes, I be happy to take a call from you. Toll Free, 1-888-747-0728 Have a great day; (Robert)

Matt Merciez

My Feedback: (34)

Robert,

Sorry for your loss. On your mechanical linkage setup, what was your linkage ratio for mecahnical advantage/disadvantage?

cap_232_2000

Thanks for the sympathy, I don't understand what you mean ??? Mechanical advantage or disadvantage ??? I used the hardware provided with the exception that I used PRo Links and aluminum servo arms.

Matt Merciez

My Feedback: (34)

Robert,

There are two critical dimensions when setting up your linkages for your control surfaces. One dimension is the length from the servo arm attachment screw to where the clevis/ball link is attached to the servo arm. The second dimension is the distance of the control survface hinge line to where the clevis is attached to the control horn.

Here is a great article on the subject: [link]http://www.horizonhobby.com/Explore/Article.aspx?ArticleID=1192[/link]

P-51B

My Feedback: (5)

Ok article, but this ARF has the control horn holes pre-drilled in the surfaces and measurements are given for the correct distances to have the connection points on the horns.

daveopam

My Feedback: (9)

Sorry about the loss. i wan't to speak about what to do when you hear flutter. You mentioned you cut power right away. I do 99% of the test flights in my club. I have found pulling elevator scrubs of the speed much faster than cutting the power. Please don't take offense. Just though I would put it out there for the next guy.


David

jmiracle

My Feedback: (9)

mechanical advantage!!! What size (length) servo horns were used, and what length control horns were used (measured from the HINGE line, not the control surface).

These distances are CRITICAL to the proper setup of a giant scale plane. If you used a servo arm longer than the control horn to get additional surface throw, then you REDUCED the torque the servo was able to supply.

Under conditions like that, it doesn't matter what brand/type/strength servo you use, you can flutter the surface just as described.

I'm sorry if this comes across as harsh...but I haven't yet read about the linkage setup and feel this is the most likely cause of the crash. If the linkage setup was correct (and INTACT after the crash!), then the next area I would look at is the servo mounts in the wing. I believe the H9 260 is a built-up wing, and as such it is possible there was a structural failure around the servo mounts which would lead to catastrophic flutter.

P-51B

My Feedback: (5)

Good point on the length of the servo arm, that is the one variable not mentioned earlier.

Oooo, and the the servo mount point, that is another good point, especially given the week glue joint of the throttle servo plate!

rcdoug

My Feedback: (8)

Gents,

I have also been the victim of aileron flutter on the 260, three weeks ago.
Using the manual's recommended set up (same arms,horns, rods, etc.)
EXCEPT the ball joints were moved IN one hole and the clevis' were OUT (longer) on the horn 1/16". JR 4721 servos on 6 volts (appx.150 oz. in.) throws as per the manual, Saito 220, 18x8 APC, PCM receiver, gaps sealed.
I had flutter on climb out at 1/2 throttle (first flight). It only completely stripped one servo, the other had some teeth left and I managed to get it down in one piece by holding some stick as the trim changed.
The left wing was pretty bad, spar broken, shear webs loose, leading edge sheeting broken from leading edge to the spar, ribs split. The right wing just had split ribs and cracked sheeting.
Oddly enough, the hinges and horns were in perfect shape, nothing loose or bent.
Horizon product support said "this has never happened before", but sent a call tag and I returned the wings. I purchased a new set and just got a credit last week.
I did e-mail Mike McConville about the problem and he mentioned that he preferred metal gear servos on the large Gas engines.
I did some serious checking on the new wings and found marginal glue joints and some missing glue on the servo mount plates.
I cut the servo arms back to 1" and ran the clevis' out to the end of the control horn rods. This cut the available travel down by 10 degrees, but on the flights this weekend I had no problems.
I believe the problem is the servo mount flexing and starting the flutter, then that strips the gears.
That would explain why this doesn't happen to all of the wings as some are put together a bit better than others.
BTW, it flys GREAT.

Doug

P-51B

My Feedback: (5)

I will definately go back and check my servo mounts plates in the wings before I fly mine.