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Old Sep 07, 2011, 06:03 PM
OOPS
Manta1's Avatar
USA, GA, Cochran
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Originally Posted by Ohio AV8TOR View Post
I have 2 of the 3DHS throw gauges and not really fond of them because they are flat and 3DHS planes have air-foiled surfaces. I switched to this and absolutely love it. Clamp it on - zero it out - and measure away hands off. So easy to program extents and dual rates with live angle feedback.

we have one of those as well and they are very nice.
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Old Sep 07, 2011, 07:15 PM
I fly, therefore, I crash!!!
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San Jose, CA
Joined Jan 2008
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Originally Posted by Ohio AV8TOR View Post
I have 2 of the 3DHS throw gauges and not really fond of them because they are flat and 3DHS planes have air-foiled surfaces. I switched to this and absolutely love it. Clamp it on - zero it out - and measure away hands off. So easy to program extents and dual rates with live angle feedback.

I have one of these and love it, with the exception that it is a bit heavy for smaller planes. I also have the Andrew Jesky one, but have been meaning to get a couple of the AeroWorks ones. One of my LHS was handling them, but stopped when the store was sold.

SteveT
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Old Sep 07, 2011, 10:16 PM
Gone Huckin'
turnerm's Avatar
Charlotte, NC
Joined Jan 2011
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So I finished my build tonight with the exception of one thing - I'm still waiting on my long servo arm to get the proper throw on my elevator. A few more questions:
  • I had to knock my dual rates down to like 60% to only get the recommended aileron throw on high rates. For low rates I had to knock it down to 40%. Does this seem right?? I was measuring the throw in inches at the end of the aileron closest to the fuse.
  • Both ailerons have just a hair of "play" where they can move before meeting resistance from the servo. I'm talking probably a millimeter. Is this normal? If not, then what adjustment needs to be made?

Any help is much appreciated!
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Old Sep 08, 2011, 07:35 AM
customstandoffs
cmala's Avatar
USA, AL, Madison
Joined Dec 2007
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The one millimeter of play is normal.


If you are measuring your throw with a ruler, hold the ruler vertical with the edge on the aft edge of the aileron. Then deflect up. It should move the distance indicated in the manual. Then check it the other direction. It sounds like you did that and used your dual rate setup to adjust for the throw you wanted. That's fine. That should give you plenty of throw to fly the plane. If you find you want more aggressive throws you can easily adjust it later.

Can't answer if your setup is normal or not without more info. With my HS65's with stock servo arms, I have everything maxed out but I haven't measured my throw. I'll go do that now.
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Old Sep 08, 2011, 07:51 AM
customstandoffs
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USA, AL, Madison
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My throws are set for the max throw I can get without binding and I'm getting
Aileron = 2.8" up and 2.8" down
Elevator = 3.3" up and 3.6" down
Rudder = 1.7" left and right

It makes sense that you would need to dial down your rates to get the throws listed in the manual especially if you are using longer servo arms. The manual is a perfectly good place to start and you can adjust from there based on your flying experience.

Once you get comfortable with the plane you can increase the throw as you like but starting with the throws stated in the manual should give you a good flying plane to start out with.

I also just realized that I need more rudder throw and need to build a servo arm to get me there but it's been flying well with the limited rudder travel that I currently have
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Old Sep 08, 2011, 08:08 AM
customstandoffs
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Just weighed mine with a 3S-2200 pack and it's 43.3 oz's

This is with HS65's, ICE Lite 50 ESC, and smaller than recommended motor
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Old Sep 08, 2011, 08:41 AM
doh!
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United States, AR, Little Rock
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Originally Posted by turnerm View Post
I had to knock my dual rates down to like 60% to only get the recommended aileron throw on high rates. For low rates I had to knock it down to 40%. Does this seem right?? I was measuring the throw in inches at the end of the aileron closest to the fuse.


Any help is much appreciated!
this is bad. Couple of reasons, you are losing resolution on the servo, and torque will suffer. Generally you want the servo endpoints to be at or as close to max (125-150%) as possible while getting the throw you need. This lets the servo move as much as possible giving a better feel to the plane. If the servo arm only moves a tiny bit in each direction you are losing this. It will be more jerky and not smooth with small stick inputs. But the worst is the second part, the servo doesn't develop full torque when it only moves a little bit. You will probably suffer blowback on your control surfaces with them like this. I was having that problem on my 42" Slick using the 3dhs long throw arms. On the rudder I used the outermost holes and got severe rudder blowback. I moved to innermost set of holes, extended the travel endpoints, and the problem was gone.
Same on my 48" Edge. I'm not using the outermost holes on the long throw arms, rather the inner ones. Still longer than the stock HS-65 arms, but my travel endpoints on the servo are now out in the 125-135% range on all surfaces.
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Old Sep 08, 2011, 08:43 AM
Gone Huckin'
turnerm's Avatar
Charlotte, NC
Joined Jan 2011
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Thanks cmala. I'm actually just using the normal servo arms that comes with the Hitec 65mg servos on the ailerons (I need a longer servo arm for my elevator and I'm waiting on that to arrive - got shipped yesterday).

I was just suprised that I was getting so much more throw on my ailerons than what the manual suggested for high rates.

When you measure the throw with a ruler - I've always heard that you should do this on the fattest part of the surface. On this plane that would be at the end of the aileron closest to the fuse. Is that where you measured?

Without reducing my high rate aileron I think I was getting closer to the 3" (up and down) that you said you're getting. Therefore I had to dial back my high rate quite a bit to get down to 1.25". But visually... a 1.25" throw seems pretty tame compared to what I was expecting to see.

I guess it's a good problem to have though - if it's not enough throw for me then I can just start pumping my high rate back up until I get it how I want it.

Oddly enough - the only surface that's giving me any issue is my elevator. I've got my travel adjust set to the max (125% on my DX6i) and I'm still getting only about 2/3 of the throw that I need. The longer servo arm should solve my issue there and I can probably dial back my travel adjust as well. I'm getting about 3" of rudder throw using a normal servo arm and 100% travel adjust. I can probably easily adjust my travel adjust (maybe up to 110% or so) to get an extra 0.5" throw but I'll start with 3" and see if that works for me.
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Old Sep 08, 2011, 08:46 AM
customstandoffs
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Originally Posted by ryan_m View Post
this is bad. Couple of reasons, you are losing resolution on the servo, and torque will suffer. Generally you want the servo endpoints to be at or as close to max (125-150%) as possible while getting the throw you need. This lets the servo move as much as possible giving a better feel to the plane. If the servo arm only moves a tiny bit in each direction you are losing this. It will be more jerky and not smooth with small stick inputs. But the worst is the second part, the servo doesn't develop full torque when it only moves a little bit. You will probably suffer blowback on your control surfaces with them like this. I was having that problem on my 42" Slick using the 3dhs long throw arms. On the rudder I used the outermost holes and got severe rudder blowback. I moved to innermost set of holes, extended the travel endpoints, and the problem was gone.
Same on my 48" Edge. I'm not using the outermost holes on the long throw arms, rather the inner ones. Still longer than the stock HS-65 arms, but my travel endpoints on the servo are now out in the 125-135% range on all surfaces.


I agree with you but do you really think it is a problem on a 48", 2.5lb plane?

I'm used to bigger stuff so maybe I'm not giving the full respect to the smaller planes that I should but if he can get full deflection when maxing out the endpoints and then needs to dial it down to get the recommended deflection as stated in the manual I don't think I would adjust the linkage so that I max out the end points to get the manual stated full deflection. Just makes it that much harder to adjust when you get comfortable with it and really want to twist it up with the max deflections on the control surfaces.
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Old Sep 08, 2011, 08:49 AM
customstandoffs
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Originally Posted by turnerm View Post
... On this plane that would be at the end of the aileron closest to the fuse. Is that where you measured?...

....
That is where I measured
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Old Sep 08, 2011, 08:53 AM
Gone Huckin'
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Charlotte, NC
Joined Jan 2011
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Quote:
Originally Posted by ryan_m View Post
this is bad. Couple of reasons, you are losing resolution on the servo, and torque will suffer. Generally you want the servo endpoints to be at or as close to max (125-150%) as possible while getting the throw you need. This lets the servo move as much as possible giving a better feel to the plane. If the servo arm only moves a tiny bit in each direction you are losing this. It will be more jerky and not smooth with small stick inputs. But the worst is the second part, the servo doesn't develop full torque when it only moves a little bit. You will probably suffer blowback on your control surfaces with them like this. I was having that problem on my 42" Slick using the 3dhs long throw arms. On the rudder I used the outermost holes and got severe rudder blowback. I moved to innermost set of holes, extended the travel endpoints, and the problem was gone.
Same on my 48" Edge. I'm not using the outermost holes on the long throw arms, rather the inner ones. Still longer than the stock HS-65 arms, but my travel endpoints on the servo are now out in the 125-135% range on all surfaces.
Thanks for the input. The odd thing is that I'm using the normal servo arm that came with the Hitec HS65MG and I'm STILL getting much more throw than the manual suggests. I didn't think about changing the ailron holes.

Sounds like I should try doing that to see if I can get my dual rate closer to 100%.

And one clarification - when people talk about travel end points - are they just talkign about the "travel adjust" setting on the radio or something else?

Like I said - on my elevator, I had to move the travel adjust to 125% and I'm still not getting enough throw so I've ordered a long servo arm to get to where I need to be. I assume this will fix my problem.

But anyway - regarding travel end points... why is it best to max these out? And I assume that the process of ensuring that you've maxed them out is to play with your travel adjust setting and then watch the servo to see if it stops moving before you max out your stick movement in that particular direction. And if it stops moving before you run out of stick room then you'd need to back down your travel adjust until you get it closely matched up. Is this right??
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Old Sep 08, 2011, 08:55 AM
Gone Huckin'
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Charlotte, NC
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Originally Posted by cmala View Post
That is where I measured
I'd be curious to see what you'd have to do to your dual rate settings to get the throw back down to the high rates listed in the manual.

Are you using standard or long servo arms for your ailerons?
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Old Sep 08, 2011, 09:03 AM
customstandoffs
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Originally Posted by turnerm View Post
I'd be curious to see what you'd have to do to your dual rate settings to get the throw back down to the high rates listed in the manual.

Are you using standard or long servo arms for your ailerons?
I'm using the longest single sided arms that came with the HS65HB's in my ailerons.

I imagine it would end up similar to your setup.

I'm curious as to why you can't get the throw out of your elevator. I'm using the longest single sided arm that came with the HS65MG's for the elevator. Looks to be the same as on the aileron.

I'm also curious to how you are getting the throw on your rudder and I'm not I need to check to make sure all my stuff is maxed out on the rudder.
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Old Sep 08, 2011, 09:17 AM
doh!
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United States, AR, Little Rock
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Originally Posted by cmala View Post
I agree with you but do you really think it is a problem on a 48", 2.5lb plane?
Absolutely. I had bad blowback on the smaller lighter 42" Slick. Same hs-65 servo. Plane weighed 35oz and was able to induce blowback in high speed knife edge quite easily. It would take full rudder input and I could barely hold a knife edge attitude. Moved the holes in and now I can knife edge loop it. Huge difference. I was stunned at the difference actually. I thought the HS-65 I had must have just been old, tired, and worn out. In the last 51" Slick I just built I took much more care in selecting servo arms that were just the right length to get the throw I wanted and having endpoints all set in the 130% range, and the difference is quite noticeable over my old 51" Slick.

Quote:
Originally Posted by turnerm View Post
Thanks for the input. The odd thing is that I'm using the normal servo arm that came with the Hitec HS65MG and I'm STILL getting much more throw than the manual suggests. I didn't think about changing the ailron holes.

Sounds like I should try doing that to see if I can get my dual rate closer to 100%.

And one clarification - when people talk about travel end points - are they just talkign about the "travel adjust" setting on the radio or something else?
If you are using the stock arms, I would set your travel adjust/endpoints (same thing, you are right) to 125 or more, and go fly. I don't worry about measuring on the ruler, I go for 35-40 degrees of throw and go fly. Which ought to be about what you get on the stock arm with your endpoints/travel adjust set all the way to maximum, or just short of where the servo stops moving. I adjust the endpoints higher and higher until the servo stops moving, and then pull it back about 5% to avoid pushing the surface too far and binding it. On my 48" Edge I think the stock arms were good on ailerons, I just used the 3dhs long arm on the elevator, and maybe the rudder. And even then I used the inner hole on the arm.


Quote:
Originally Posted by cmala View Post
Like I said - on my elevator, I had to move the travel adjust to 125% and I'm still not getting enough throw so I've ordered a long servo arm to get to where I need to be. I assume this will fix my problem.

But anyway - regarding travel end points... why is it best to max these out? And I assume that the process of ensuring that you've maxed them out is to play with your travel adjust setting and then watch the servo to see if it stops moving before you max out your stick movement in that particular direction. And if it stops moving before you run out of stick room then you'd need to back down your travel adjust until you get it closely matched up. Is this right??
yes, that process is right for adjusting endpoints.
The reason for adjusting them to max has been covered by Ben a few times in here, but mainly analog servos don't develop their full torque until they are moving. So you want the servo arm moving. When you have the arm dialed back on endpoints so that it barely moves each direction, then it isn't developing any of the rated torque for it. (See above about blowback on my 42" Slick.... my endpoints were at like 45-55%). Also the resolution. Think about it this way, the servo is capable of moving about 45-60 degrees in each direction (depending on subtrim you set). So lets say that is 500 "Steps" in each direction, Or about 1000 total. But if you limit the arm movement to only a tiny bit each way, you have cut this down to maybe like 200 "Steps" in each direction, and so each step is a bigger jump to the next one, and the control surface can look very jerky when being moved rather than smooth. This can show up in the air too. Ever had a plane that you couldn't quite trim? One trim bump made it too much one way, one trim bump the other way made it too much the other way? This is why... if the servo arm used more of the available travel then each trim step is smaller and you should be able to lock in the trim setting better.
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Old Sep 08, 2011, 09:18 AM
Gone Huckin'
turnerm's Avatar
Charlotte, NC
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Originally Posted by cmala View Post
I'm using the longest single sided arms that came with the HS65HB's in my ailerons.

I imagine it would end up similar to your setup.

I'm curious as to why you can't get the throw out of your elevator. I'm using the longest single sided arm that came with the HS65MG's for the elevator. Looks to be the same as on the aileron.

I'm also curious to how you are getting the throw on your rudder and I'm not I need to check to make sure all my stuff is maxed out on the rudder.
Very interesting. What trasnmitter are you using? In reading back through this thread I think I read somewhere that different trasnmitters behave differently - meaning in this case that they cannot utilize the full servo travel without increasing the travel adjust... and even then, it appears that I'm STILL not getting the full travel of the servo (on the elevator at least).
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