Author Topic: Elevator to Flap ratio (Read 18441 times)

Chris Fretz · « **on:** February 24, 2016, 10:14:51 AM »

What is best when it comes to flaps? Do you equal amount of flaps to elevator movement, more elevator an less flap or more flap an less elevator?

john e. holliday · « **Reply #1 on:** February 24, 2016, 10:18:49 AM »

In my experience, never more flap than elevator. On my newest I have about 20 degree flap and 30 degree elevator. In the old days it used to be 45 degrees up and down on the moving surfaces. Then we learned we never use that in a normal situation.

Randy Powell · « **Reply #2 on:** February 24, 2016, 10:25:30 AM »

Depending on several factors, it's probably best to start off with 1 to 1. It's nice if you have an adjustable system so you can dial in more or less elevator if you need it.

Tim Wescott · « **Reply #3 on:** February 24, 2016, 10:38:37 AM »

What Randy said, except I might start with a bit more elevator than flap.

It depends on the airframe and the airplane weight, so you'd like to start with something conservative and then try different settings until you're happy.

If you're a beginner then just bung it on 1:1 elevator:flap, or maybe 3:2 elevator:flap, and go fly.

Better yet, if you're a total beginner and you're still crashing all the time don't distract yourself with flaps -- get several flapless planes like the Flight Streak or the Sig Skyray and just go fly. Flaps make maneuvers slightly prettier, but they make repairs much harder and they complicate trimming. So beginners should leave them off and concentrate on learning to fly.

FLOYD CARTER · « **Reply #4 on:** February 24, 2016, 11:21:59 AM »

It depends heavily on the airframe configuration. Short tail moments, like many of the Palmer designs, fly better with a reduced flap movement. With a very long tail moment, flaps are largely unnecessary. Somewhere in-between, is the ideal geometry for most effective flap action. There, a 1;1 ratio is the normal place to start the trimming schedule.

FC (not an expert)

Chris Fretz · « **Reply #5 on:** February 24, 2016, 03:24:48 PM »

Quote from: FLOYD CARTER on February 24, 2016, 11:21:59 AM

It depends heavily on the airframe configuration. Short tail moments, like many of the Palmer designs, fly better with a reduced flap movement. With a very long tail moment, flaps are largely unnecessary. Somewhere in-between, is the ideal geometry for most effective flap action. There, a 1;1 ratio is the normal place to start the trimming schedule.

FC (not an expert)

Would the Smootie work better with reduced flap? How does the Nobler fit in? If its a heavy airplane or light airplane would that change things? What can you expect from the airplane if you have too much flap movement?

Tim Wescott · « **Reply #6 on:** February 24, 2016, 03:33:24 PM »

Quote from: #Liner on February 24, 2016, 03:24:48 PM

Would the Smootie work better with reduced flap? How does the Nobler fit in? If its a heavy airplane or light airplane would that change things? What can you expect from the airplane if you have too much flap movement?

Dunno about Smoothie or Nobler.

Heavier airplanes benefit from more flap:elevator ratio (note that I'm swapping ends on you -- it's what people usually think, AFAIK).

With too little flap movement the plane will look like it's skidding through the turns with the tail to the outside -- it has to be, for it to generate lift. With too much flap movement the plane will look like it's standing on its nose through the turns.

If you're good at gauging angles by eye you can get pretty close to the right ratio by flying upright and inverted, and noting the angle of the plane. If it's equally tail down both ways then it needs more flap. If it's equally tail up both ways then it needs less flap. If it's more tail down in upright than in inverted, then the flap-elevator bias needs to be adjusted -- I'm pretty sure that the elevator needs to go up in this case. This is all in Paul Walkers trim articles in Stunt News.

What class are you flying in?

Chris Fretz · « **Reply #7 on:** February 24, 2016, 04:35:08 PM »

Quote from: Tim Wescott on February 24, 2016, 03:33:24 PM

Dunno about Smoothie or Nobler.

Heavier airplanes benefit from more flap:elevator ratio (note that I'm swapping ends on you -- it's what people usually think, AFAIK).

With too little flap movement the plane will look like it's skidding through the turns with the tail to the outside -- it has to be, for it to generate lift. With too much flap movement the plane will look like it's standing on its nose through the turns.

If you're good at gauging angles by eye you can get pretty close to the right ratio by flying upright and inverted, and noting the angle of the plane. If it's equally tail down both ways then it needs more flap. If it's equally tail up both ways then it needs less flap. If it's more tail down in upright than in inverted, then the flap-elevator bias needs to be adjusted -- I'm pretty sure that the elevator needs to go up in this case. This is all in Paul Walkers trim articles in Stunt News.

What class are you flying in?

When you ask what class I fly in I assume you mean for contest flying? I don't fly in any contests, I just go out an fly at whatever ballfield is available that day. I quit flying for 20yrs an started back up last year. Now Im just looking at it all different than 20yrs ago I guess, maybe try to do it better. I'll have to check out that trim article. Ha ha is there "trim for dummies" in there?

MikeyPratt · « **Reply #8 on:** February 24, 2016, 05:45:18 PM »

Quote from: FLOYD CARTER on February 24, 2016, 11:21:59 AM

It depends heavily on the airframe configuration. Short tail moments, like many of the Palmer designs, fly better with a reduced flap movement. With a very long tail moment, flaps are largely unnecessary. Somewhere in-between, is the ideal geometry for most effective flap action. There, a 1;1 ratio is the normal place to start the trimming schedule.

FC (not an expert)

I agree with Floyd, the longer you make the tail moment (and TVC) the flaps become close to unnecessary at a point. Stick with 1 to 1 control ratio for most flapped models. If you are a very light builder, then you can try different settings to enhance flight performance, but the model has to be a light weight.

The Skyray 35 and the Primary Force perform great with out flaps. My newest design, the P-Force XL it even better and has a very good corner with out flaps.

Later,
Mikey

Tim Wescott · « **Reply #9 on:** February 24, 2016, 06:41:41 PM »

Quote from: #Liner on February 24, 2016, 04:35:08 PM

When you ask what class I fly in I assume you mean for contest flying? I don't fly in any contests, I just go out an fly at whatever ballfield is available that day. I quit flying for 20yrs an started back up last year. Now Im just looking at it all different than 20yrs ago I guess, maybe try to do it better. I'll have to check out that trim article. Ha ha is there "trim for dummies" in there?

In that case just set the ratio at 1:1 (or 3:2 elevator:flap) and go tear up the circle. You won't care too much about getting it trimmed out to a gnat's eyelash unless you're flying as good as someone flying Expert -- and if you're that good, you should be competing!

Steve Helmick · « **Reply #10 on:** February 25, 2016, 12:11:16 AM »

Depending on which Pittsburg you live in/near, you may find some locals that can help you get better, faster. While Tim's sort of right about not worrying about adjusting the flap/elevator control ratio, the experimenting will teach you something, and it's all valuable knowledge. The other point I'd make is that the better you can make the plane fly, the longer it will last, as well as the more enjoyment you'll get out of it per flight. Make the plane fly good...don't try to adapt your flying to make up for the less than optimized plane.

Steve

Chris Fretz · « **Reply #11 on:** February 25, 2016, 05:22:52 AM »

Quote from: Tim Wescott on February 24, 2016, 06:41:41 PM

In that case just set the ratio at 1:1 (or 3:2 elevator:flap) and go tear up the circle. You won't care too much about getting it trimmed out to a gnat's eyelash unless you're flying as good as someone flying Expert -- and if you're that good, you should be competing!

Ive got a few YouTube videos if you're bored enough to watch them an have any pointers...
crude but I managed a vertical 8 this year.

this has the VROOM in it.

this is a heavy old old Smoothie I picked up last yr.

What do you guys use to weigh airplanes?

Avaiojet · « **Reply #12 on:** February 25, 2016, 06:17:07 AM »

Gotta hand it to a guy that flies off dirt.

Chris Fretz · « **Reply #13 on:** February 25, 2016, 07:29:25 AM »

Back in the 90s all I wanted was to be able to do a horizontal 8. Last year I found I was doing it all wrong since what I did were lazy 8s.

Chris Fretz · « **Reply #14 on:** February 25, 2016, 07:36:29 AM »

Quote from: Avaiojet on February 25, 2016, 06:17:07 AM

Gotta hand it to a guy that flies off dirt.

Flying off dirt is not a good practice?

john e. holliday · « **Reply #15 on:** February 25, 2016, 09:43:05 AM »

I've flown off dirt many times when the grass on the ball diamond is not cut short enough.

Chris Fretz · « **Reply #16 on:** February 25, 2016, 10:04:42 AM »

Quote from: Steve Helmick on February 25, 2016, 12:11:16 AM

Depending on which Pittsburg you live in/near, you may find some locals that can help you get better, faster. While Tim's sort of right about not worrying about adjusting the flap/elevator control ratio, the experimenting will teach you something, and it's all valuable knowledge. The other point I'd make is that the better you can make the plane fly, the longer it will last, as well as the more enjoyment you'll get out of it per flight. Make the plane fly good...don't try to adapt your flying to make up for the less than optimized plane. Steve

There is only one Pittsburgh with a h, in Pa where we drink pop an use gum bands N'at

Tim Wescott · « **Reply #17 on:** February 25, 2016, 10:44:26 AM »

Quote from: #Liner on February 25, 2016, 10:04:42 AM

There is only one Pittsburgh with a h, in Pa where we drink pop an use gum bands N'at

From Wikipedia https://en.wikipedia.org/wiki/Pittsburgh_%28disambiguation%29

Pittsburgh, Kingston, Ontario, Canada
Pittsburg, California (formerly Pittsburgh), U.S.
Pittsburgh (Atlanta), a neighborhood of Atlanta, Georgia, U.S.
Pittsburgh, North Dakota, U.S.
Pittsburgh Junction, Ohio, U.S.

That's not including a couple of other places that are nicknamed Pittsburgh (with an 'h').

FLOYD CARTER · « **Reply #18 on:** February 25, 2016, 10:58:44 AM »

Someone once observed; there is a "Main St." in 75% of all US cities. Someday, I'll do a study to see if this is true.

FC

john e. holliday · « **Reply #19 on:** February 25, 2016, 12:57:45 PM »

Sounds like he is close to Brodaks.

Chris Fretz · « **Reply #20 on:** February 25, 2016, 02:00:13 PM »

Quote from: john e. holliday on February 25, 2016, 12:57:45 PM

Sounds like he is close to Brodaks.

Yes Brodaks is about an hour away from me. I was at the hobby shop a few times last year.

Chris Fretz · « **Reply #21 on:** February 25, 2016, 02:05:29 PM »

Quote from: Tim Wescott on February 25, 2016, 10:44:26 AM

From Wikipedia https://en.wikipedia.org/wiki/Pittsburgh_%28disambiguation%29

Pittsburgh, Kingston, Ontario, Canada
Pittsburg, California (formerly Pittsburgh), U.S.
Pittsburgh (Atlanta), a neighborhood of Atlanta, Georgia, U.S.
Pittsburgh, North Dakota, U.S.
Pittsburgh Junction, Ohio, U.S.

That's not including a couple of other places that are nicknamed Pittsburgh (with an 'h').

Ok ok I'll give you the North Dakota one! But the other three are named after Pittsburgh Pa an Canada don't count.

john e. holliday · « **Reply #22 on:** February 25, 2016, 05:06:06 PM »

Will we see you at Brodaks in June?

Chris Fretz · « **Reply #23 on:** February 25, 2016, 06:18:53 PM »

Quote from: john e. holliday on February 25, 2016, 05:06:06 PM

Will we see you at Brodaks in June?

You know I stopped by there last year for about an hour standing under a tree wile it rained most of the time just to see what all went on for that fly in. I enjoied watching how good those guys were. I never seen combat in person an I still don't get how they don't tangle the lines doing it. You guys fly in it? I can't even get an airplane to fly good enough to do the pattern

I don't think I have much of a place flying in it. When is it in june? I'm sure I'll have to work that week.

Chris Fretz · « **Reply #24 on:** February 26, 2016, 10:08:00 AM »

Quote from: MikeyPratt on February 24, 2016, 05:45:18 PM

The Skyray 35 and the Primary Force perform great with out flaps. My newest design, the P-Force XL it even better and has a very good corner with out flaps.

Later,
Mikey

Is the Primary Force still discontinued?

Chris Fretz · « **Reply #25 on:** February 26, 2016, 01:27:51 PM »

Quote from: MikeyPratt on February 24, 2016, 05:45:18 PM

I agree with Floyd, the longer you make the tail moment (and TVC) the flaps become close to unnecessary at a point. Stick with 1 to 1 control ratio for most flapped models. If you are a very light builder, then you can try different settings to enhance flight performance, but the model has to be a light weight.

The Skyray 35 and the Primary Force perform great with out flaps. My newest design, the P-Force XL it even better and has a very good corner with out flaps.

Later,
Mikey

Do you have any tips for how to build them light, are we talking build a rip skip a rib kind of thing? How about these ARFs are they light or do you guys change them too? What do you use the weigh airplanes, a fish scale?

Tim Wescott · « **Reply #26 on:** February 26, 2016, 03:07:48 PM »

Quote from: #Liner on February 26, 2016, 01:27:51 PM

Do you have any tips for how to build them light, are we talking build a rip skip a rib kind of thing? How about these ARFs are they light or do you guys change them too? What do you use the weigh airplanes, a fish scale?

I use a postal scale and a gram scale ("jewelry" or "cocaine" scale, depending on the set you run with).

In descending order of importance:

1: Don't get too enthusiastic about larding on the paint.

2: Be sparing with the glue -- if it squeezes out of the joint, it's too much.

3: Use light wood.

Avaiojet · « **Reply #27 on:** February 26, 2016, 03:12:30 PM »

I have this ARF Pathfinder. "Assembled" it right out of the box with no changes. Weighs 55.2 oz with an OS LA 46.

I don't know if it's heavy or light, but that's what it weighs.

Chris Fretz · « **Reply #28 on:** February 28, 2016, 04:39:46 AM »

Quote from: Tim Wescott on February 24, 2016, 03:33:24 PM

If you're good at gauging angles by eye you can get pretty close to the right ratio by flying upright and inverted, and noting the angle of the plane. If it's equally tail down both ways then it needs more flap. If it's equally tail up both ways then it needs less flap. If it's more tail down in upright than in inverted, then the flap-elevator bias needs to be adjusted -- I'm pretty sure that the elevator needs to go up in this case. This is all in Paul Walkers trim articles in Stunt News.

How cant I get my hands on this article?

Mike Haverly · « **Reply #29 on:** February 28, 2016, 09:32:36 AM »

The articles are in Stunt News. Join PAMPA for more information and many more articles. Also, this article can be found here. http://flyinglines.org/pw.trimflow4.html

Chris Fretz · « **Reply #30 on:** February 28, 2016, 12:50:44 PM »

Hey fellas I just built a R/C Carl Goldberg G26 Shoestring 54" into a C/L with a 46 LA an it weighs 60.5oz. Is that good, bad or ugly?

Chris Fretz · « **Reply #31 on:** February 28, 2016, 12:55:25 PM »

Quote from: Mike Haverly on February 28, 2016, 09:32:36 AM

The articles are in Stunt News. Join PAMPA for more information and many more articles. Also, this article can be found here. http://flyinglines.org/pw.trimflow4.html

Super! Thanks!

Mike Haverly · « **Reply #32 on:** February 28, 2016, 01:55:11 PM »

Quote from: #Liner on February 28, 2016, 12:50:44 PM

Hey fellas I just built a R/C Carl Goldberg G26 Shoestring 54" into a C/L with a 46 LA an it weighs 60.5oz. Is that good, bad or ugly?

It all comes down to wing loading. That is probably too heavy to be of much use competitively, (ugly). Still, like has been mentioned many times, a well built straight airplane is much easier to fly, even if it is heavy. Performance with a given wing loading varies with the design.

Chris Fretz · « **Reply #33 on:** February 28, 2016, 03:19:34 PM »

Quote from: Mike Haverly on February 28, 2016, 01:55:11 PM

It all comes down to wing loading. That is probably too heavy to be of much use competitively, (ugly). Still, like has been mentioned many times, a well built straight airplane is much easier to fly, even if it is heavy. Performance with a given wing loading varies with the design.

Ok for the fun of it my Nobler is 47.5oz what about that?

Tim Wescott · « **Reply #34 on:** February 28, 2016, 03:31:38 PM »

Quote from: #Liner on February 28, 2016, 03:19:34 PM

Ok for the fun of it my Nobler is 47.5oz what about that?

I bit heavy but reasonable-ish.

Tim Wescott · « **Reply #35 on:** February 28, 2016, 03:35:07 PM »

Quote from: #Liner on February 28, 2016, 12:50:44 PM

Hey fellas I just built a R/C Carl Goldberg G26 Shoestring 54" into a C/L with a 46 LA an it weighs 60.5oz. Is that good, bad or ugly?

RC? -- I looked for this on the web and didn't fine anything. As Mike said, the wing area matters quite a bit, so if the thing has more area than a typical 54" span stunter then you may be OK, or OK-ish. My current ride is 61" span, about 680 square inch area, and weighs about 64 ounces. It flies marvelously.

Chris Fretz · « **Reply #36 on:** February 28, 2016, 03:39:16 PM »

Ok good to know. No I have a better idea of whats what.

Chris Fretz · « **Reply #37 on:** February 28, 2016, 03:49:33 PM »

Quote from: Tim Wescott on February 28, 2016, 03:35:07 PM

RC? -- I looked for this on the web and didn't fine anything. As Mike said, the wing area matters quite a bit, so if the thing has more area than a typical 54" span stunter then you may be OK, or OK-ish. My current ride is 61" span, about 680 square inch area, and weighs about 64 ounces. It flies marvelously.

540 area on this one.

Tim Wescott · « **Reply #38 on:** February 28, 2016, 05:32:37 PM »

Quote from: #Liner on February 28, 2016, 03:49:33 PM

540 area on this one (Shoestring -- TaW).

That's really heavy for stunt, probably not too bad for scale or sport.

Chris Fretz · « **Reply #39 on:** March 02, 2016, 06:58:16 AM »

Quote from: Tim Wescott on February 28, 2016, 03:31:38 PM

I bit heavy but reasonable-ish.

Hey Tim, what would be an ideal weight on that old nobler for stunt? Could I lighten it up taking the old I guess its silk span off an using Monokote?

Tim Wescott · « **Reply #40 on:** March 02, 2016, 11:18:09 AM »

Taking off a finish is almost as much work as building a new airframe from scratch. I'd just fly the thing, and maybe plan on building a new one.

How heavy you can get away with in a Nobler depends on the engine -- if you're trying to pull it with a Fox 35, then you want it as light as possible. If you're pulling it with a 46LA or other "modern" stunt engine (40FP, Enya 40, Magnum 36, etc.) then that weight is probably OK.

I went from upper Intermediate to lower Expert with a Fancherized Twister that weighs 54 ounces. A 48 ounce Nobler with the right engine should be fine.

Steve Helmick · « **Reply #41 on:** March 02, 2016, 03:19:46 PM »

As for the Noblur (per George's biz card logo)...George said his favorite one was 45 oz, but some weighed 50 oz. The heavier they are, the more likely 1:1 flap/elevator ratio will work well. If you build one at 35 oz, you'd best plan on increasing the elevator (2:3 ratio) and reducing handle spacing. This is where folks usually mess up, by using a 3" bellcrank and short flap horn.

I watched your videos. If you learned the pattern, I'd put you in Intermediate, since you can fly inverted. That's the biggest struggle for most. You've got the basic skills to do it if you wish. One of the benefits of flying the pattern is that your models will tend to last longer. Why? Because you'll know when the tank is about to run dry without any engine burping or belching.

Steve

PS: I'm constantly amazed at how many town names are repeated all over the world. Well, not Sammamish or Issaquah, but Hillsboro, Redmond, Auburn, and the like...

Chris Fretz · « **Reply #42 on:** March 02, 2016, 04:03:06 PM »

Quote from: Steve Helmick on March 02, 2016, 03:19:46 PM

As for the Noblur (per George's biz card logo)...George said his favorite one was 45 oz, but some weighed 50 oz. The heavier they are, the more likely 1:1 flap/elevator ratio will work well. If you build one at 35 oz, you'd best plan on increasing the elevator (2:3 ratio) and reducing handle spacing. This is where folks usually mess up, by using a 3" bellcrank and short flap horn.

I watched your videos. If you learned the pattern, I'd put you in Intermediate, since you can fly inverted. That's the biggest struggle for most. You've got the basic skills to do it if you wish. One of the benefits of flying the pattern is that your models will tend to last longer. Why? Because you'll know when the tank is about to run dry without any engine burping or belching. Steve

PS: I'm constantly amazed at how many town names are repeated all over the world. Well, not Sammamish or Issaquah, but Hillsboro, Redmond, Auburn, and the like...

Thanks Steve! Could you elaborate on the 3in bellcrank? When do you use a 3in an when do you want a 4in? When do you want to use the inside hole an outside hole for the pushrod? I never messed around with handle spacing either, I always just used a EZ adjust.

Tim Wescott · « **Reply #43 on:** March 02, 2016, 04:43:58 PM »

Quote from: #Liner on March 02, 2016, 04:03:06 PM

Thanks Steve! Could you elaborate on the 3in bellcrank? When do you use a 3in an when do you want a 4in? When do you want to use the inside hole an outside hole for the pushrod? I never messed around with handle spacing either, I always just used a EZ adjust.

Over the years, the trend has been toward longer and longer bellcranks, and using the full throw of the bellcrank to control the plane. This puts the lightest load on the flying wires, and makes the plane the most controllable when lines are slack.

I'd use a 4" bellcrank on anything with a wingspan over four feet. One of these days I may even give a 5" or 6" bellcrank a whirl in my "full size" stunter, although most of the top guys seem to think that 4" is big enough.

On a normal stunter you want to use a control arrangement that gives you about a +/- 20 degree throw on the elevator when the bellcrank is at +/- 45 degrees or so. You can either do that by using the outer hole of the bellcrank and nice long horns, or by using some more-inner hole in the bellcrank and shorter horns. Longer horns mean less sensitivity to slop in the control system; shorter horns are easier to fit. You picks your poison...

Steve Helmick · « **Reply #44 on:** March 02, 2016, 11:16:58 PM »

Pretty much what Tim said, except that I'd suggest the biggest BC you can fit in any given design. Might not fit in a 1/2A, but that's really an example of where a 4" BC would help the most. It's all about leverage, and that pesky lack of line tension. The zoot term for this lack of leverage and the lack of line tension needed to drive the controls is "The Netzeband Wall". Named for one of the first engineering-types to analyze and write about the physics of hemispherical flight on two steel wires.

Steve

Chris Fretz · « **Reply #45 on:** March 07, 2016, 07:29:16 AM »

Quote from: Tim Wescott on February 28, 2016, 05:32:37 PM

That's really heavy for stunt, probably not too bad for scale or sport.

What prop would you try on that with the LA .46? 11-4?

Mark Scarborough · « **Reply #46 on:** March 07, 2016, 08:12:47 AM »

Quote from: #Liner on March 07, 2016, 07:29:16 AM

What prop would you try on that with the LA .46? 11-4?

I had best luck with the APC 12.25x3.75 prop on the LA 46
I would not go any less than an 11.5 x4 APC,,