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Building Tips and technical articles. => Building techniques => Topic started by: Chris Fretz on February 24, 2016, 10:14:51 AM
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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?
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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.
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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.
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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.
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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)
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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?
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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?
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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?
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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
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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!
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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. H^^ Steve
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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...
https://youtu.be/jQLdDyTdQFI crude but I managed a vertical 8 this year.
https://youtu.be/_TTt44wCJ2I this has the VROOM in it.
https://youtu.be/r914J1JMOKI this is a heavy old old Smoothie I picked up last yr.
What do you guys use to weigh airplanes?
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Gotta hand it to a guy that flies off dirt.
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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.
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Gotta hand it to a guy that flies off dirt.
Flying off dirt is not a good practice?
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I've flown off dirt many times when the grass on the ball diamond is not cut short enough.
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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. H^^ Steve
There is only one Pittsburgh with a h, in Pa where we drink pop an use gum bands N'at n1 ;D
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There is only one Pittsburgh with a h, in Pa where we drink pop an use gum bands N'at n1 ;D
From Wikipedia https://en.wikipedia.org/wiki/Pittsburgh_%28disambiguation%29 (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').
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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
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Sounds like he is close to Brodaks. LL~ LL~ LL~
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Sounds like he is close to Brodaks. LL~ LL~ LL~
Yes Brodaks is about an hour away from me. I was at the hobby shop a few times last year.
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From Wikipedia https://en.wikipedia.org/wiki/Pittsburgh_%28disambiguation%29 (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.
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Will we see you at Brodaks in June?
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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 HB~> 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.
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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?
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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?
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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.
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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.
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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?
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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
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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?
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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!
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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.
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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?
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Ok for the fun of it my Nobler is 47.5oz what about that?
I bit heavy but reasonable-ish.
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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.
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Ok good to know. No I have a better idea of whats what.
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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.
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540 area on this one (Shoestring -- TaW).
That's really heavy for stunt, probably not too bad for scale or sport.
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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?
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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.
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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. y1 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... ;D
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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. y1 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... ;D
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.
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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...
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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. D>K Steve
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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?
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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,,