HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Aug 10, 2005, 05:20 AM
Proud member of LISF and ESL
LI, New York, USA
Joined Mar 2003
24,570 Posts
Cool
Trailing edge camber adjustments - Best Practices?

I have been flying thermal sailplanes about 2.5 years and full house for a little over a year.

I have not played with camber settings yet. My Futaba 9C can handle it so I guess it is time. I am asking about best practices and practical experience.

I just put up an Prism T-tail with a SD 7037 air foil. So far I like the plane a lot. Now I am trying to dial it in and figure out what settings work best.

When you talk about applying full TE camber, how much are we talking?

Is full TE camber better than just adding a little flap?

I can put this on a side slider, a dial or I could put this on a switch and go to one or two presets. What would be the recommendations here.

Should I be using full TE camber adjustment as soon as I confirm lift, or are there times when it should not be used?

I appreciate any guidance.

My questions are general, but if you have any specific suggestions on how I implement this on my Futaba 9C, that would be appreciated as well. Today I have crow on the stick ( no choice) flap/elevator on left slider. I was thinking of putting this on right slider but it could go on a 2 way or three way switch as well. I don't typically use the dials.

Thanks!
aeajr is offline Find More Posts by aeajr
Reply With Quote
Sign up now
to remove ads between posts
Old Aug 10, 2005, 10:41 AM
I'm all about that bass
rdwoebke's Avatar
United States, IN, Indianapolis
Joined Feb 2004
15,322 Posts
I'm not expert on full house planes by any means. But I am planning on following some of the suggestions in this thread when I get a full house plane again.

http://groups.yahoo.com/group/soaring/message/133159
rdwoebke is offline Find More Posts by rdwoebke
Reply With Quote
Old Aug 10, 2005, 10:51 AM
Registered User
Denmark
Joined Apr 2004
312 Posts
Hi Aeajr,

http://www.gliders.dk/triming_and_se...der_wi_eng.htm

cheers

Erik Dahl Christensen
Denmark
erikdahlchriste is offline Find More Posts by erikdahlchriste
Reply With Quote
Old Aug 10, 2005, 01:33 PM
LSF V,LSF Secretary,AMA Lifer
Robglover's Avatar
Huntsville
Joined Oct 2003
2,077 Posts
The 7037 does benefit from changes in camber. If you want to go fast reflex it. If you want to slow down add camber. How much and when is up to the pilot. Better pilots know their planes well enough to decide when to add what. That's how we pick who wins the contest. There are some general rules, but the best rule is to try it and see what works for you. This is easier to do if you like to fly a lot.

happy trails
Robglover is offline Find More Posts by Robglover
Reply With Quote
Old Aug 10, 2005, 03:15 PM
LSF - IV
Hostage-46's Avatar
United States, TX, Highland Village
Joined Jan 2003
3,210 Posts
To Rob's point, it really is about knowing when and how much to use camber and reflex. Like you aejr I'm just getting to the point where I've been experimenting. My current full house ship, a 7035 sage wing Sapphire, seems to like camber more then reflex. My XP-4 was designed to leverage camber and reflex to optimize performance.

I find it interesting that most folks tend to user sliders to vary camber. In full scale soaring, you generally select a particuar setting that will yield the known airfoil polar, which is why it seems like a switch, with a given,consisant setting makes more sense.

I continue to noodle through both options, slider vs. switch.
Hostage-46 is online now Find More Posts by Hostage-46
Reply With Quote
Old Aug 10, 2005, 03:31 PM
Proud member of LISF and ESL
LI, New York, USA
Joined Mar 2003
24,570 Posts
I think a switch seems much simpler but I don't know if we are talking 1/16 inch or 50% or what the range should be. I am leaning on putting on a slider to experiment and once I find what seems to work, move that to a 2 way or 3 way or a flight condition switch.
aeajr is offline Find More Posts by aeajr
Reply With Quote
Old Aug 10, 2005, 03:44 PM
Registered User
nuevo's Avatar
United States, AL, Madison
Joined May 2002
2,272 Posts
Quote:
When you talk about applying full TE camber, how much are we talking?
2-3 degrees down in general

Quote:
Is full TE camber better than just adding a little flap?
yes. Full TE camber, all surfaces deflected so the TE is still straight.

Quote:
I can put this on a side slider, a dial or I could put this on a switch and go to one or two presets. What would be the recommendations here.
Use whatever suits you best. Not a big issue here.

In the last year, I migrated to using my flight-mode switch for different camber positions. That is because I'm flying airplanes where the airfoil designer has designated specific positions for thermal, cruise, launch, speed, etc.

On one plane, the designer has not given such information, so I experimented with xfoil to find what I believe is the best location. To compute the "best" angle for thermal, etc. you would need to compute the % hinge location on your plane, and then use xfoil or Profili to generate polars for the Re and surface deflection angles you are interested in. Then compare the polars. Using this technique takes quite a bit of study, knowledge, estimating, and insight on your part.

Profili is a lot easier to use, but I find myself using xfoil directly more often.

I'm not solidly on the "switch" side, and can see the advantages of both.
nuevo is offline Find More Posts by nuevo
Reply With Quote
Old Aug 10, 2005, 04:26 PM
Proud member of LISF and ESL
LI, New York, USA
Joined Mar 2003
24,570 Posts
Quote:
Originally Posted by erikdahlchriste
Hi Aeajr,

http://www.gliders.dk/triming_and_se...der_wi_eng.htm

cheers

Erik Dahl Christensen
Denmark
Erik, I have seen your paper before. It circulates at our sailplane club often. Thanks for sharing it.
aeajr is offline Find More Posts by aeajr
Reply With Quote
Old Aug 10, 2005, 04:27 PM
Proud member of LISF and ESL
LI, New York, USA
Joined Mar 2003
24,570 Posts
Quote:
Originally Posted by rdwoebke
I'm not expert on full house planes by any means. But I am planning on following some of the suggestions in this thread when I get a full house plane again.

http://groups.yahoo.com/group/soaring/message/133159
A discussion by Joe Wurts around setting up a sailplane and computer radio is about as good as it gets. Thanks!
aeajr is offline Find More Posts by aeajr
Reply With Quote
Old Aug 11, 2005, 03:16 PM
LSF V,LSF Secretary,AMA Lifer
Robglover's Avatar
Huntsville
Joined Oct 2003
2,077 Posts
Joe's stuff is pretty much gospel to me, hard to argue with his success.

Camber presets are working well for me the last year or so, for a couple reasons.

I think that the recent crop of airfoils were designed to have a couple sweet spots. One for high camber, and one for low camber settings.

If you lay a stainless steel rule down on the top of the airfoil and flex it to follow the wing surface it helps you to visualize smooth and kinky flow paths. Camber the wing just right you can spot when you have a good smoothly curved upper surface. This will likely correspond to the thermal setting.

If you do the same on the lower wing surface you should get pretty close to the best low camber setting, good for runs between thermals.

Set the presets to get your wing to those two spots and then ignore the slider, instead focus your attention on keeping the plane centered in lift. Flying smoothly in lift will trump whatever you do with camber settings.
Robglover is offline Find More Posts by Robglover
Reply With Quote
Old Aug 11, 2005, 04:19 PM
LSF - IV
Hostage-46's Avatar
United States, TX, Highland Village
Joined Jan 2003
3,210 Posts
Quote:
Originally Posted by Robglover
Joe's stuff is pretty much gospel to me, hard to argue with his success.

Camber presets are working well for me the last year or so, for a couple reasons.

I think that the recent crop of airfoils were designed to have a couple sweet spots. One for high camber, and one for low camber settings.

If you lay a stainless steel rule down on the top of the airfoil and flex it to follow the wing surface it helps you to visualize smooth and kinky flow paths. Camber the wing just right you can spot when you have a good smoothly curved upper surface. This will likely correspond to the thermal setting.

If you do the same on the lower wing surface you should get pretty close to the best low camber setting, good for runs between thermals.

Set the presets to get your wing to those two spots and then ignore the slider, instead focus your attention on keeping the plane centered in lift. Flying smoothly in lift will trump whatever you do with camber settings.


Once again .... very useful thread. I will look at the plots but the steel ruler appoach is genious in its simplicity.

Something we've grown to expect from you guys. How in the world did people survive before RCSE and RC Groups

I've also gone to the mode switch approach as I'm not able to otherwise tell the difference because of my experience level.
Hostage-46 is online now Find More Posts by Hostage-46
Reply With Quote
Old Aug 12, 2005, 11:49 AM
Registered User
Wisconsin
Joined Apr 2002
281 Posts
Hi Ed,

I have a Sapphire with the 7037. I have it set up on the new 9C Futaba. Ed Whyte's suggested settings for the model is 1/16" reflex, 3/16" camber and I believe it is 1/2" drop on the flaps and 3/8" drop on the ail for launch. These settings may need some elevator compensation. Especially the launch settings.

What I have settled on is:

1/16" reflex with no elev. compensation.
The launch settings as listed with elev. compensation.
My camber setting is at about 1/8" with a very slight amount of elev.

I don't use any of the knobs. I have the launch, camber and reflex settings set up on switches. I also set up the camber on the left slider. Basically, I set up the slider, as you had mentioned, to be able to "play" with the amount of camber to see how the model reacted. After a while, it seemed as though I was always coming to the same setting on the slider. So, I decided to set the camber switch up with the setting that I was arriving at with the slider. I am sure that there are pilots out there that like to be able to vary the setting. But for me it is a lot easier to flip the switch on and off as needed rather than to fiddle with the slider. Using the slider, you have to mover it till it beeps to find center. Count the clicks needed. Then move it to the beep again. The switch is a lot more convenient.

When doing the testing of the set ups, I would set the camber or reflex up on the slider and then use the elev. trim to adjust elev. compensation. After I determined how much if any elev. was needed, I then set up the elev. on the switch too.

I have also been playing with flaps coupled to elev. a little. Not sure if I like it yet or not. There are some situations where it works very well. It is activated by a switch, so I can turn it on or off as needed.

PS:

On the slider. Since reflex is set at 1/16" and really not varied, I have "0" setting programed on the up side of center and the camber set up when moving the slider down. This way I can park the slider in the all the way up position when not in use. Helps to keep from making an accidental trailing edge adjustment.

Since the adjustments are now set on the switches, I really don't use the slider much.

BTW, I really like the 9C Super Series.

Duey
Kestrel is offline Find More Posts by Kestrel
Reply With Quote
Old May 04, 2012, 10:59 AM
Proud member of LISF and ESL
LI, New York, USA
Joined Mar 2003
24,570 Posts
Let's bring this back, for the new glider pilots. Anyone have any new comments?
aeajr is offline Find More Posts by aeajr
Reply With Quote
Old May 04, 2012, 04:58 PM
LSF303 / AMA Life Member
tkallev's Avatar
USA, IL, Wheeling
Joined Jan 2003
3,170 Posts
Less is more ...
tkallev is offline Find More Posts by tkallev
Reply With Quote
Old May 04, 2012, 06:27 PM
Proud member of LISF and ESL
LI, New York, USA
Joined Mar 2003
24,570 Posts
When I started this thread I was a pretty new glider pilot. I was asking for help. I had yet to even set-up camber settings on my Airtronics Legend. I had just purchased a Futaba 9C.

Since then I have move from an Airtronics Legend to a Polecat Thermal Dancer to a Supra, a Graphite and now have a Supra Pro on the table waiting to be completed. I fly competition in my club's contests, www.lisf.org , and in the Eastern Soaring League in the Expert class. www.flyel.org

While I am not a top competitor I can say that there are a lot of launches to my credit. Through trial and error, and with the help of some really talented pilots, I have learned a lot.

Today I fly a pair of Futaba 9C Super radios which I have had now for several years and plan to keep for the forseeable future. These are not top of the line sailplane radios but I like them. They allow me to run a set of camber changes that work for me. I could do more if I wanted.

So, as to my best practices question, I can now provide somewhat of an answer to my own question of 5 years ago.

There are three ways to know how to set up your camber settings. One is to try the ones in the manual, if there are suggestions. Second is to talk to your friends who have the same plane, or to post that question on this forum and ask what works for them on that plane.

Remember that the camber settings that will likely work best will depend on a number of variables. One is airfoil, one is wing loading and one is how you fly. There may be others.

Using the camber settings recommended for a Supra and putting them on a Pike Perfect might be an OK starting point, but these are two very different gliders with different airfoils and diffrent wing loadings. The optimum set-up is likely to differ somewhat.

I said there were three ways. The third it to play. To experiment and try and see what works for you. I am going to share some of my set-ups. You can use these as starting points but your smileage will vary based on your plane and your flying style. Some people recommend elevator trim changes as you change camber settings and some do not.

It is worth noting that the Supra Wing, based on Drela airfoils, are molded in reflex. What that means is that my normal cruise position has the trailing edge slightly down from where you would expect to see it. When I go to reflex my wing actually looks like it is in cruise. I hope that is right because that is how I have it set.

Of course others will differ on the camber settings they use and how they use them. I hope they will chime in. I am certainly not the authority on this.

While some people like variable camber that is controlled from a slider or a dial, I prefer presets that are switch activated. This puts the surface to the same place every time. My camber settings are either on or off, not part way between.


Launch - switch setting - Flaps and ailerons down about 20 % Lots of lift
but lots of drag, but on tow the drag is not a problem. Some people prefer to have the ailerons at a lesser setting, but I go straight across. I don't apply any elevator trim change during launch.


Reflex - switch setting - In reflex flaps and ailerons up about 2 mm - this is a speed setting for wind penetration or to run from sink. Slightly reduced lift but much reduced drag. I don't change elevator trim in reflex.


During a winch launch - I ride up to about 60 degrees on the arc, then switch to reflex, dip the nose for half a second, gain some speed and pull up into the zoom. At the top I level off and flip the switch to cruise, my normal flying setting. The hunt for lift begins.

So during my launch I use three camber settings. On the 9C these are set on a 3 way switch so they are mutually exclusive. I can't accidentailly have my launch setting on when I flip to cruise or reflex.
.
If I hit a thermal and actually confirm I am in lift, I flip a different switch and my flaps and ailerons drop about 3 mm to make the wing slightly more undercambered. I thnk I have a slight bit of down elevator added to this mix. This is my thermal camber setting. More lift and a little more drag but in a thermal it will help me capture more energy and climb faster.

Normally I move between cruise and thermal camber setting during a flight. If I need to run away from sink or run into the wind I may go into reflex to pick up speed but in many flights I don't use reflex.


That's it. That is all I have set.


I would love to have more experienced, more talented pilots comment on these settings and their use of camber changtes on their plane. Or to suggest other set-ups that work for them.

Perhaps you fly a Pike or a Legend or a .... something else. What are your settings and your best practices?

Do you change elevator trim with your camber settings?
When do you use your camber settings?
Do you have more than one thermal setting?

I am told some airfoils don't like reflext and some don't like amber. I don't know which these would be.

Some say your launch settings should have less down in the ailerons to avoid tip stalls. Others say that it doesn't matter. What is your opinion?


Inquiring minds want to know.
aeajr is offline Find More Posts by aeajr
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Eclipse 7 trailing edge camber on switch EricSoar Hitec/Multiplex USA 8 Mar 22, 2004 06:54 PM
Help! Eclipse 7 trailing edge camber/reflex...NOT? SpiritQuest Hitec/Multiplex USA 2 Jul 02, 2003 12:20 PM
Help! Trailing edge of left and right wing different thicknesses by 1 mm. The Other Dave Foamies (Kits) 6 Feb 17, 2002 06:52 AM
Washout from leading or trailing edge? g00bd0g Power Systems 6 Aug 04, 2001 09:37 PM
how do you mount on trailing edge Bruinjess Sport Planes 5 Jul 10, 2001 02:22 AM