RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

It appears that when setuping up a plane, we are always compromising one facet for another (increased throw for a loss of precision/mechanical advantage).

If using the newer digital servos (increased servo resolution ie JR 8611), can you still tell a difference in flight performance/precision when going from a 1:1 relationship to a 0.5:1 relationship?

The reason why I ask the above question is on my next plane, I plan on using the 8611's and was hoping to setup the plane with a 1:1 relationship for large 3D throws but still have excellent precision for IMAC type flying by using the digital servos.

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

Doug,
Thanks for the reply, I thought when you go into your dual rates menu, doesn't it change the servo movement thru the ATV setting,
(I have Futaba) and that's what you DON'T want to do?

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

The digitals make it better for sure.. but I believe I can still tell.

ATV's determine the total throw. Dual Rates modify the throw permissible by the ATV's.

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

This is a great thread. I had been doing some research on this topic before this thread was created, but this has put the icing on the cake.

Thanks

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

if you are using futaba Zap then you set the ATV first 140% is the max and probably to far as the servos are not always centerd correctly (futaba) and you will hit the mechanical stop one way. ( I use the sub trim to move the servo back to its true centre. you can then adjust even further with the AFR function so its easy to overthrow the servos and burn them out. I always set the servo so that it is one "notch" back from the mechanical stops with a true centre then never change them. the linkages are then set as Doug quite rightly says although all of my 3D planes are set with a 1-1 ratio making sure everything is strong and the geometry is correct.

Dave

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

Here we go again..BLAH, BLAH, BLAH.. There is amount of planes (Funtana .90) That are defected. Some seem not to be. Some are. There are too many problems with it not to be. Period.

Put Digital servos in and spend the money. You will still have the problems....If you get a defected one.

If you do not think there are defected ones out there and it is all the owners fault then you do not have an open mind.

I mean come on guys it has been a month and I have read here over8 planes having the same problems.
You got ot admit there is a problem with a batch of them. Not everybody is doing the same thing!

If nothing is wrong with your plane I am jealous and wish I would have got a good one! But Please....Don't bash. It will come out in the end that somnething was indeed wrong with a batch. It is being looked into as we speak. So before you bash. Wait awhile and see....

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

What does this have to do with Matt's question?

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

No matter how you set it up. If the plane is one of the ones in the defected batch it won't help anything. That is what it has to do with the question. Now any more questions? I been following this. I been watching and I cannot believe some of the things I have read. There is a defect in some of these planes. So lighten up on the bashing. Of all people if you are with JR/DA ZDZ engines....you should have a very open mind.

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

Startsivs and spooky,

it appears the only bashing going on is you guys, i have read this thread and it is an informative thread with lots to learn (exactly what this type of Forum is for)

just because you have had a bad experiance (bit like your mum did :D ) now show a bit of maturity and stick with your thread and let normal people discuss and learn from this thread.

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

Bashing? Just because you didn't like me replying and disagreeing to what you said? That is bashing? That is freedom of speech Pal. All I said that there were a bad batch of these planes. Hopefully Horizon will do the right thing. From reading the threads they are not getting back with the customers that have got a bad planes out of the bad batch. How can that be bashing? MUM? you have a lot of nerve buddy. All I see you doing is starting more crap just because I do not agree with you. What do you work for Horizon? Defending the plane? If so Do something about it and quit *****ing and hoping it will all go away!

When I see that Horizon is going to stand behind what they sale and admit there is a problem with a batch of them then I will enjoy the informative part. You can make all the jokes and bash all you want...The plane I had was defected just like the other 8 of them here that we know about. Trust me you would be the same if if happen to you!

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

Startsvis and Spooky, I'm not the type to bash and I haven't bashed you and normally wouldn't ever make comments to you guys, but you guys have been whinning all over RCU. I understand that you had a bad experience with your plane and I'm sorry about that, but that does not mean that every thread on RCU with the word "Funtana" in it has to be taken over by you guys stating that it is bad or a piece of crap. There may be a defect, then again there may not be a defect. You guys really need to lay off all the whinning. Obviously, some are enjoying their planes and some are getting ready to put theirs together and unfortunately some have had bad experiences. Honestly, 1-2% of the planes that have had problems is no reason for Hanger 9 to do a recall.

I wish you guys well and hope you get your planes going again soon, but I personally have gotten tired of reading replies that state, "Defect, Defect, Defect" and "I told you so." No one likes a smart @$$ guys. I really hate to say it, but grow up and act your age. You are making too big of a deal over this topic. This thread is for all comments, but I think everyone has heard your side, "DEFECT".

Thanks and I hope you get your planes going again soon,
DTB

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

Can someone measure the root chord, tip chord, and span of the aileron on the Funtana 90? I'm at work and can't measure mine. I want to show you guys some hard data on forces required for this, but I need these measurements 1st.

Thanks..

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

I am at work, but if I remember correctly the aileron's root is 5.5", tip is 3.5" and 28" span. I think I remembered correctly.

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

28.5 x5 3/4 root x 3.5 tip is how i mesure it so your about right.

would not want to drive along at 80MPH and stick that out the window!!

spooky, chill out a bit school starts again in a couple of weeks, dont waste your holidays

Dave

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

Thanks guys.. one last question. How far above the HINGE LINE (not the surface) is the bottom hole on the stock control horn?

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

Spooky, dont worry i forgive you. people sometimes get *****y when theyre on the pill

Apart from your comments i have found this thread very useful, and has helped me setup the linkages on my latest plane

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

1 and 1/8" to botom hole 1 and 1/2 to top hole (aprox)

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

OK.. I think possibly there is a misunderstanding of how servo ratings work and what they mean.

People see a servo rated at 60 ounce inches and think that's it.. 60 ounces.. Unfortunately that's not the complete picture. A torque rating is actually a combination of 2 things.. a weight, and a distance. That rating means the servo using a 1" arm, can lift 60 ounces without stalling. If you increase this servo arm to 2" long, you reduce the lifting ability of the servo by 1/2 to 30 ounces. This is why your complete pushrod geometry is so important.

Let's take the Funtana 90 aileron as an example and I'll show you some things that might startle you;

Base Values:
Aileron: 5.75" root, 3.5" tip, 28.5" span = 263 square inches of area.
Speed: 40 mph. Now reality is once you start to roll, the drag will rise and the speed will drop, but let's just say for example the speed stays the same.
Servo arm and control horn in the same plane of rotation.

With a perfect 1:1 pushrod geometry, where 35 degrees of servo movement results in 35 degrees of surface movement, the force required to move the aileron to full deflection at this speed is roughly 60 ounce inches.

If I now shorted my servo arm to .75 inches, increase my ATV's so I get 50 degrees of travel either direction from neutral, the servo moves a full 50 degrees, the surface moves the same 35 degrees, but the servo is only required to generate 37 ounce inches of torque.

Now let's go the other direction. If I lengthen the servo arm to 1.25", the servo will only move 27 degrees for the surface to move 35 degrees, but the force required jumps to just over 87 ounce inches of torque.

OK.. now the Funtana is setup slightly different since the servo rotates perpendicular to the axis of rotation of the aileron control horn. So the calculations change a bit. If we use the same references as above, same values, and so forth.. here's the numbers that come up assuming your pushrods are pefectly oriented in the neutral position.


Arm:Horn - Power Required
1":1.125" setup - 50 ounce inches required.
.75:1.125" setup - 35 ounce inches required.
1.25:1.125" setup - 75 ounce inches required.

So this again illustrates how important mechanical advantage is for simply moving the surfaces let alone combating flutter.

Did this make sense or did I totally confuse you guys?

EDIT: Updated 2nd set of numbers to reflect actual Funtana 90 setups using the bottom control horn position of 1 1/8" distance from hinge-line.

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

makes perfect sense, I assume we don’t see mass balanced ailerons (like most elevator and rudders) because there is a bigger chance of flutter?

also its worth mentioning that if you set up your surface with say a 1/4" servo arm and a 1/4" horn (1-1) and you grabbed your aileron and gave it a good tweak something would definitely "move" or brake. do the same with a 2" servo arm and a 2" horn (1-1 again) and it will be as strong as a horse. (it will also allow full movement as the pushrod wont hit the wing)


Dave

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

Doug, no confusion here. Thanks for the info. Maybe something like this could be added to the manual, now if folks would just sart reading the manual.

Ed M.

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

I agree 100%.

It's even better that you posted this here and with pictures to boot! Others can learn and not make the same mistake.

Thank you!

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

FUNTANA .90 Is a defected airplane Period end of story.

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

I think you and Startsivs are the same person. You both write the same way, have the same misuse of grammar, and both misspell words the same.

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

Is that all you got out of this thread? This isn't even about the Funtana 90. This started as a post by Matt about his Extreme Flight Yak-54 having flutter problems. There's a lot of useful information in this thread that can help people avoid similar problems with all kinds of airplanes.. and all you get out of it is to post that?

Open your mind SpookySivs.

RE: Flutter problems and Mechanical linkage Setup Lesson Learned
 

or go back to school with the rest of the kids!