RE: eyeball help  
View related threads: (in this forum | in all forums)

Tower Hobbies
Enter up to 4 keywords or Tower stock numbers
Logged in as Guest



Users viewing this topic: none
  Printable Version
       



All Forums >> RC Airplanes >> Pattern Flying >> Classic Pattern Flying >> RE: eyeball help
Page: <<   < prev  1 [2] 3   next >   >>  

Login
Message << Older Topic   Newer Topic >>
RE: eyeball help - 6/18/2008 5:45:08 PM   
bob27s



Posts: 4895
Joined: 4/9/2002
From: Cleveland, OH, USA
Status: offline
quote:

ORIGINAL: Skylane

Hi,

The three horizontal rolls should take about 5 seconds for the type of pattern this plane was designed for. So, 1.5 sec per roll is just about right.

Jeff



I agree....

that was the standard timing for the roll sequence....

If you want a higher rate for half-rolls on stalls and Cuban-8, no problem there. Set the high rated to what ever feels comfortable. Set the low rate to match the 3x5 roll sequence.

Years ago I never touched the roll dual rate. Used the same rate for everything.

Also, if you have not sealed the control surface gaps, especially on the ailerons ........ do so before adjusting the control throws. Just doing that will nearly double your roll rate and will make the rolls smoother and more consistant.

Bob


_____________________________

Bob Brassell
Jett Engineering - Engine Mfg Support Forum Host

(in reply to Skylane)
       Post #: 26

RE: eyeball help - 6/18/2008 9:24:31 PM   
WEDJ



Posts: 1071
Joined: 2/21/2007
From: East Haddam, CT, USA
Status: online 		Back then, I used high rate for 3 x 5 sec rolls, and low rate (2+ sec rolls) only for the slow roll maneuver. Elevator high rate for spin, snaps and landing, low rate for everything else. Rudder rate was slaved to throttle position.

_____________________________

Pilot dog FTW!

(in reply to bob27s)
       Post #: 27

RE: eyeball help - 6/24/2008 1:11:25 AM   
dszabo2


 

Posts: 185
Joined: 3/2/2005
From: Branchburg, NJ, USA
Status: offline 		Had a chance to fly again this week end with the rates on my radio increased to 140% through the radio. My original estimations of the roll rate were off by quite a bit. With the increased travel I timed the roll at just over 2 second. When I put it back to 100% I was at a 3 second rate that would be nine second for three rolls. Both measured at close to full speed.

Sorry for the wrong original post on the rate.

Im using futaba 3004 servos, 4.8 volts and the ailerons are sealed over the entire length on the bottom side of the wing.

Any thoughts on what could be wrong????

Dave

(in reply to WEDJ)
       Post #: 28

RE: eyeball help - 6/24/2008 2:11:18 AM   
Free Bird


 

Posts: 752
Joined: 11/20/2005
From: Somewhere Out There, USA
Status: online 		Where is the pushrod connected on the servo arm and the aileron control horn? Further in on the servo arm = less throw. Further out on the control horn = less throw.

FB

(in reply to dszabo2)
       Post #: 29

RE: eyeball help - 6/24/2008 2:20:13 AM   
dszabo2


 

Posts: 185
Joined: 3/2/2005
From: Branchburg, NJ, USA
Status: offline 		My original deflections were set to 1/4" on low rate and 3/8" on high high rate. The 140% setting probably increased the throw to about 1/2 inch

I do have it set up with differential throws, therfore the down throw is less than the up throw This is done mechanically by use of a round servo arm

Dave

(in reply to Free Bird)
       Post #: 30

RE: eyeball help - 7/2/2008 4:07:04 AM   
patternwannabee


 

Posts: 243
Joined: 10/8/2002
From: Mars, PA, USA
Status: offline 		Hi Dave,

Sorry, I've been out of town last week.

Did you go with the "classic" single servo in the center of the wing installation or one servo per wing half?

If classic, how is the aileron movement (moves freely?), and can the servo withstand some resistance? Actually, I figure you know this since you fly 3d, but I thought I'd ask anyway.

Assuming you have unimpeded aileron servo movement (strong and fast), then it's probably an aerodynamic concern. Perhaps you could pose the question in the aerodynamic forum.

I installed my servos 1 per wing panel and on its side. I was never wanting for aileron throw or roll speed.

3 sec/roll is pretty darn slow. You could try increasing throw little by little using a bigger servo wheel until you achieve the roll rates you desire.

Good luck.

(in reply to dszabo2)
       Post #: 31

RE: eyeball help - 7/2/2008 3:17:57 PM   
dszabo2


 

Posts: 185
Joined: 3/2/2005
From: Branchburg, NJ, USA
Status: offline 		patternwannbee

I do have it set up with the classic single servo in the center and as I mentioned, it is set up with mechanical differential thows. The surfaces do move free and response seems OK, but thats in a static mode. I now question if a futaba 3004 servo on 4.8 volt will have enough torque. The plane is a little over weight coming in at 7.5 lbs, its supposed to weight 6.0 lbs (too much clear coat LOL)

I did change to a longer servo arm but did not fly it this past weekend. I do have a higher torque digital servo and I think I will switch it in to try out this weekend.

Dave

(in reply to patternwannabee)
       Post #: 32

RE: eyeball help - 7/3/2008 9:19:59 PM   
UStik


 

Posts: 167
Joined: 10/28/2006
From: Augsburg, GERMANY
Status: offline 		If all else fails, you could put strips of adhesive tape (masking tape or Scotch tape) on the sheeted parts of the wing in front of the ailerons (and if that fails even on the sheeting in front of the covering) - trip strips.

It's just a shot in the dark, but it's so easy to take some tape along to the field and apply it to the wing (which looks very smooth). At least it's easier than checking the airfoil shape and leading edge radius over the whole span.

I personally would do the reverse of what you did, I'd set no aileron differential in the first place. If you set up substantial differential you'll get yaw and lose roll rate, and the huge deflections are like slamming on the brakes, making things worse.

< Message edited by UStik -- 7/3/2008 10:17:35 PM >

(in reply to dszabo2)
       Post #: 33

RE: eyeball help - 7/3/2008 9:25:56 PM   
bob27s



Posts: 4895
Joined: 4/9/2002
From: Cleveland, OH, USA
Status: offline 		if you can post a few photos that would be helpful.

With the throws you identified, the plan should fly well with a reasonable roll rate.

Something else is amiss...


_____________________________

Bob Brassell
Jett Engineering - Engine Mfg Support Forum Host

(in reply to dszabo2)
       Post #: 34

RE: eyeball help - 7/4/2008 3:06:01 AM   
dszabo2


 

Posts: 185
Joined: 3/2/2005
From: Branchburg, NJ, USA
Status: offline 		Tomorrow I will post some pictures showing the aileron / servo set up.

(in reply to bob27s)
       Post #: 35

RE: eyeball help - 7/4/2008 8:52:49 AM   
UStik


 

Posts: 167
Joined: 10/28/2006
From: Augsburg, GERMANY
Status: offline 		... and a close-up of the overall wing shape, please! It's so interesting!

If the ailerons merely stir in the wake of a separation bubble, any discussion of servo, linkage, throw, and differential would be pointless.

(Not to offend you, I just like to muse about such things and love to know for sure if I'm right or wrong. )

< Message edited by UStik -- 7/4/2008 8:59:51 AM >

(in reply to dszabo2)
       Post #: 36

RE: eyeball help - 7/4/2008 4:04:51 PM   
dszabo2


 

Posts: 185
Joined: 3/2/2005
From: Branchburg, NJ, USA
Status: offline 		Here are pictures of my original set up.

Attachments
Click to see fullsize image.
Click for fullsize 		Click to see fullsize image.
Click for fullsize 		Click to see fullsize image.
Click for fullsize 		Click to see fullsize image.
Click for fullsize

(in reply to UStik)
       Post #: 37

RE: eyeball help - 7/4/2008 4:41:11 PM   
UStik


 

Posts: 167
Joined: 10/28/2006
From: Augsburg, GERMANY
Status: offline 		Thanks a lot, that's a very nice airplane! I don't see any odd things, just not sure about the leading edge radius, and really seems to be very smooth wing surface (and a thick wing). Sorry, no idea other than the shot in the dark (the tape).

(in reply to dszabo2)
       Post #: 38

RE: eyeball help - 7/4/2008 4:59:12 PM   
patternwannabee


 

Posts: 243
Joined: 10/8/2002
From: Mars, PA, USA
Status: offline 		Hi Dave,

I can't help but think that there's some resistance in your aileron servo setup.

I'm reminded why I'll no longer use the center aileron servo setup. So much that needs to be adjusted and so much that can go wrong.

It looks like the right aileron ball is canted pretty far forward. Seems to me that when the servo pulls on this link, the ball link might bottom out causing resistance?

Also, maybe it's the angle of the picture, but it seems the Left aileron pushrod is significantly longer than the right?

I'm assuming the additional bends in the control horn are to avoid hitting something in the servo compartment?

If indeed the aileron travel is smooth and unimpeded, then I agree with Bob27s...something else (aerodynamically) is amiss.

BTW, the ball link on the aileron horn is probably not the most secure type of link. Should it come loose, then you've got real sloppy ailerons that could lock in an unusual position.

(in reply to dszabo2)
       Post #: 39

RE: eyeball help - 7/4/2008 5:29:20 PM   
dszabo2


 

Posts: 185
Joined: 3/2/2005
From: Branchburg, NJ, USA
Status: offline 		I dont care for the the ball link set up either. I was forced to use it because of the bend I needed to put in the push rod to clear the fuselage. I have it quite secure.

There is no slop in the ailerons, so I dont think going to dual servos will buy me anything. I also put a digital servo in for inreased torque. If that doesnt help I'll do away with the differential throw. To UStik's point, increasing throws will be like putting on the brakes.

Dave

(in reply to patternwannabee)
       Post #: 40