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General control line discussion => Open Forum => Topic started by: Avaiojet on October 31, 2012, 12:23:14 PM
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The model is The Loser, I would like The Loser to have working flaps.
Obviously, the bellcrank to flap is the first pushrod. This pushrod will be exiting from the top of the inboard wing and there will be a flap control horn on the inboard flap.
I'm considering an adjustable horn at the flap end. I purchased one to see what they are like.
I'm thinking of having another adjustable control horn on the outboard flap with that pushrod going to the elevator horn.
Two questions.
1) These adjustable control horns, Do they ever fail?
2) That second control horn on the outboard flap, has this been done before on a profile model?
Thanks in advance.
Charles
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On profile models I like to have the controls on the inboard side where they get less exhaust exposure. What you want to do should work. I think you could accomplish the same with one adjustable horn on the flaps and another on the elevator.
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As indicated by the picture, you asked the question too late.
I like the controls outboard because anything you can move outboard reduces tip weight & total weight.
I like two pushrods off the bellcrank. The inboard works the flaps, the outboard works the flippers. Thus, both surfaces are independently adjustable.
The "daisy chain" system of working the flipper off the flap doubles the stress on the short pushrod. This mistake can be overcome with heavy metal, but the two control surfaces are still interconnected.
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As indicated by the picture, you asked the question too late.
Paul, Jim,
Look again Paul! I'm not using those flaps, they are .1875" in thickness, both are bent and held on with tape. n~
I like two pushrods off the bellcrank. The inboard works the flaps, the outboard works the flippers. Thus, both surfaces are independently adjustable.
Interesting, wider exit hole in the wing sheeting but simpler to set up and adjust independentally. I like it!
What about adjustable control hornes? Do they have issues?
Thanks for the reply,
Charles
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As indicated by the picture, you asked the question too late.
I like the controls outboard because anything you can move outboard reduces tip weight & total weight.
I like two pushrods off the bellcrank. The inboard works the flaps, the outboard works the flippers. Thus, both surfaces are independently adjustable.
The "daisy chain" system of working the flipper off the flap doubles the stress on the short pushrod. This mistake can be overcome with heavy metal, but the two control surfaces are still interconnected.
That is a good plan but how do you handle the ratio change? That would all have to be done at the elevator horn.
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Charles, is your plane just assembled for a photo or is it glued up? I noticed the lack of center planking.
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Charles, is your plane just assembled for a photo or is it glued up? I noticed the lack of center planking.
Dick,
Observant!
Gravity and tape is holding everything together.
Charles
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I use double horns, ball links and what we call carbon rods. The ball links are mounted using JB Weld. This is a Tom Morris setup. The ball links mount is inserted into the carbon tube glued in with JB Weld. I wrap wire for an inch or two on the end of the joint to keep the tube from splitting. The wire is glued on with more JB Weld. This is a way to rig controls so that they can be trued accurately. Also the stiff rod helps control responsiveness.
I hope you can make out the double horn in the two pictures. The wire wrap is clear.
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Dennis,
Thanks for the reply.
Nice looking model! Covering looks really tight!
I've used Tom's HDWE only once on The New American, built up fuselage. Tom offers great products.
I see you have two pushrods to the elevators because they are split, correct? Any reason why you didn't use an offset control horn attached to bent wire on the elevator? This would allow for only one pushrod.
Can you adjust at both the flap and elevator ends? Same degree of movement on both control surfaces?
Second photo: both pushrods are connected to the same hole on the control horn?
I made some lines on paper for two pushrods comming off the bellcrank, I think they will get in the way of each other? Also, I always mount my bellcranks with the pivit arm pointing towards the outboard wing.
Covering? Type of hinges?
Thanks again for the reply!
Charles
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No just one pushrod to the elevators. Two different planes. One is a modified Twister (top). The other is a modified Magician. Twister plans put the purshrod on the outboard side of the fuse. I'm not sure of the reasoning for doing that. Outboard weight as opposed to inboard? Dunno. I followed along.
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I adjust the controls so that there is more elevator than flap movement. This is the base setting. Always possible to readjust the ratio.
I have started to use ball links on both ends of the pushrod. I think this makes the linkage somewhat more rigid, less slop, especially as the control system gets worn in use. A wire into a non-bearing bell crank will wear after a while. This may not ultimately matter. New ball links are very stiff when screwed onto the mount. I don't anticipate that they will screw out. For my new models I plan to use some locktite. In the past I have smeared JB weld on the threads at one end, leaving the other end adjustable.
Pin hinges when the wood is at least 3/16" thick. Otherwise cloth. I run the stab pushrod from the flap horn/pushrod mount. Depending upon the geometry of the model, I may run the elevator pushrod from the same mounting screw as the flap pushrod. Geometry can always be adjusted at the stab.
These models use monokote on the bays. After years of working it, my results are o.k. All solid surfaces are doped, covered with silkspan, doped on top of that. Filled. The common method. I haven't tried a urethane top coat yet. But am intrigued. On my future full fues models, my plan is to silkspan solid surfaces and use polyspan on the bays.
I just remembered that I'm currently installing these controls in a Tanager wing. I hope the picture bellow is useful.
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Dennis,
You like red?
Two different planes. Am I getting old or what? LL~ Not that bad a mistake seeing they are both red. n~
You have plywood under your bellcrank? We would use those bellcranks for R/C, didn't really know they were popular for CL?
Modified Twister? Sig Twister? I'm using a modified Sig Twister wing on The Loser. Looks like an airfoil that will perform, I hope so.
How well does your Twister fly? Flaps helped?
Like you, I added half ribs also. I was going to sheet and capstrip, but that adds weight. Probably would have if the ribs were thinner in thickness.
The flap thing must be one of your mods? How thick are your flaps? Because of the TE I made, my flaps have to be .25" thick at the flap LE.
I've never seen Twister plans. What is the span of your Twister? Did you ever weigh the finished wing? What size engine are you using on it?
Your planes have names or AMA numbers?
Want some of that lettering, no charge.
Charles
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Thanks Charles for your offer! I'll take you up on it.
I wrote out my reply earlier today then pressed the wrong button and poof. All gone. I'll try again.
I love red! I've been trying to get a color scheme that looked decent. Black and Red is the best I could come up with so far. A while back I was into Insignia Blue before that metallic green. What can I say.
The Twister served me well after Dan Banjok worked on trimming it for a few hours. It was built using stock Twister wood. Weighed in at 42 ounces in flying shape. Could have been lighter. The trailing edge and wing spars were webbed. I believe the flaps were 3/16" hard. Yes, half ribs, wing tips, I moved the stab back 2 inches. Halfway Fancherized. Twisters are usually built with moveable flaps. The Fancherized and straight versions both showing them in the plans. FP 40 power. This plane served me well for years. At the beginning of 2012, flying in the cold, the engine burped towards the end of a Pattern. I figured there was enough fuel, like always, to finish the shapes. At the cross of the overhead eight the engine quit. Controline no man's land. Splat. Friends told me afterwards "well sure in cold weather the air is denser and the mixture needs to be richer... you're not going to get the same run..."
The Magician uses a Walter Umland wing kit. I used Midwest plans as a reference. Wing measures nearly fifty inches with wingtips. I forget the wood thickness I used for the flaps. At least 3/16s. The flaps were widened about an inch at the inboard end, the taper towards the tip was opened up until it looked right. The stabilizer lengthened about 30% and moved back 2 inches or so. The fues is a rigid piece of very light 1/2inch. The nose doublers 1/8 inch five ply. Wing spars and trailing edge webbed. It weighs in, ready to fly, between 35 and 36 ounces. Depending upon the contest and the thumb on the scale. Surprised me how light it turned out. Power is a Tower 40. A very good flyer. Light on the controls. Handles the wind well. Dan Banjok told me to fly this plane instead of the Vector we were trying our best to trim out. The plane works very well. Very little trimming needed. The new hasn't warn off.
The bell cranks in these models are floated between two pieces of 3/8" square spruce. (I'm not near my shop this evening, need to measure and be sure.) 1/8" holes are drilled in the top and bottom, the post for the bell crank fits there. The spruce squares are tied into the main spars. The crank is located on the post with wheel colors and two pieces of medium fuel tubing, one top, one bottom. The Tom Morris method. Suspenders and a belt. It works.
The bell cranks are Tom Morris phenolic(?). Kind of look like peg board raw material soaked in epoxy resin. A spot of oil where they pivot and they stay lubed for the life. (Life of my models, anyway.) I use the big control horns and double them, for rigidity and in order to get the geometry right. The new Tanager wing (it was hanging up in my shop for 2 years at least, getting bumped into and chipped) probably won't use the top hole. Whatever works (looks right). The control horns are mounted on thin ply, top and bottom.
Allen Brickhaus was the guy who told me to double the control horns way back when. I wasn't exactly sure what he meant. So I did what you see. I've been bothering Allen for years, asking him why he never took a picture of my builds. ;D After razzing him again at this past NATs, he went over and snapped a pic. The next day, there it was in the daily news of events, a picture of the doubled flap horns and ball links. Rest of the Magician out of the picture. Allen!
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The Looser has nice lines. Old Time look. Good luck.
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I like the lines of the Looser. Old Timey. Good luck. Nice woodwork.
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I like the lines of the Looser. Old Timey. Good luck. Nice woodwork.
Dennis,
How sweet of you, thanks for that compliment.
You almost made me cry.
BTW. The Loser didn't always look like this. Did you see the original thread?
It started out as another model even with a different wing. I needed a slap, I did get it and finally woke up.
I believe I'm on track now.
Hey! What about that lettering for your model? Got any ideas?
Charles
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Thanks again Charles. Dan Banjok drew a beautiful set of plans for me of a Brown B2, the 30s Pylon racer. A red original. Using a sort of Twister wing, as a matter of fact. Thicker airfoil. Let me look at the full size replica pictures of the plane. The ribs are cut. I've selected wood for the built up fues. Finish the Looser. Are you using moveable flaps? Looks that way. That helps. I'd plank the stab and elevator with very light 1/16". Should be very stiff then. See how the Looser flies. Keep moving forward. CL needs new looks.
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Dennis,
I know the Brown B2, that's Miss LA. I actually have graphics for that someplace, Not graphics actually, but the art someplace. I made graphics for a R/C model some years ago. The builder wasn't fussy, so the art isn't perfect. I remember this job well because as many times as I asked, I never got photos. Some guys just won't send out photos.
Are you using moveable flaps?
Yes I am.
I'd plank the stab and elevator with very light 1/16". Should be very stiff then.
I thought about that. I was thinking 1/32". I was also thinking of sheeting the LE to spar area with 1/32".
Charles
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I've kinda "semi-made up," my mind on my flap linkage?
I have a horn on bent wire from TM but the horn is off center and if placed on the bottom, it's on the outside.
If I use it I won't have to purchase one or something else for the elevator. If I use it, the flap to elevator pushrod will have to be on the outside also.
Charles
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Usually the flap horns are on the top of the flap. Elevator horns on the bottom. This assumes that the stab centerline is above the wing centerline. Did you do the opposite? Or put the stab on the same centerline as the wing? There might be a theoretical advantage to using a horn brased to the wire connection. In other words the bellcrank torque is delivered directly to the connecting wire, so that the twisting torques are more centered, unlike delivering the torque to a single flap, having the torque transfer through the wire, to the other flap. In practice, however, using external horns mounted to a single flap, doesn't appear to create a problem. Not on 40 sized profiles.
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Usually the flap horns are on the top of the flap. Elevator horns on the bottom. This assumes that the stab centerline is above the wing centerline. Did you do the opposite? Or put the stab on the same centerline as the wing? There might be a theoretical advantage to using a horn brased to the wire connection. In other words the bellcrank torque is delivered directly to the connecting wire, so that the twisting torques are more centered, unlike delivering the torque to a single flap, having the torque transfer through the wire, to the other flap. In practice, however, using external horns mounted to a single flap, doesn't appear to create a problem. Not on 40 sized profiles.
Dennis,
Thanks for the reply.
Yes, I know the flap horns generally are on top and the elevator horns are on the bottom. ;D
I sent Tom a drawing for this off center piece but I drew it incorrectly. n~
The horn was to be offset on the left underneath. No, the Stab is not on the same thrust line as the wing. I don't believe I would design or build a model that way.
This thing costs 7.00 and change, I don't know where else I could use it?
I understand your flap torque issue, cleaver guy, I never considered this? If I have a wire horn made with both horns on the same wire, this would eleaviate the twisting of the flaps in two directions, correct? Or limit it?
Seems I'd be best off to have that one horn on the inside flap then continue off of that to the elevator horn on the inside bottom.
Thanks again,
Charles
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Dennis is correct in being concerned about having equal torque transmitted to both flaps through what is functionally a torsion bar. It looks a little strange, a great many people give it no consideration at all. Folk like me, for example. At least until Derek Moran and I got real serious about our Wimpact models. Which have really excellent control systems one would not expect to see on Pukey Profiles and this is not limited to just the flap horns.
Ditto above for elevators horns, especially on a profile.
Apologies to all who have an interest in this subject, especially as there is quite a lot more to discuss. But with posts like this sometimes just going "Whoof!" when deleted for no good reason I am simply not interested in making the effort. And at least some of the techniques and hardware have been posted elsewhere over the years.
Dan
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Apologies to all who have an interest in this subject, especially as there is quite a lot more to discuss. But with posts like this sometimes just going "Whoof!" when deleted for no good reason I am simply not interested in making the effort. And at least some of the techniques and hardware have been posted elsewhere over the years.
Dan
Dan,
Just by mentioning it, you probably triggered a "whoofing" of this entire thread. Mysterious forces are at work here.
Keith
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Mysterious forces are at work here.
Nothing mysterious. If you start a thread, you have the option of removing it.
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I believe I have few choices for the pushrod system on The LOSER.
I'm not sure if I can deal with a 3/32" thick wire that holds the control horn. The flaps are 1/4" thick at the LE so I'll use 1/8" wire.
I also decided on having two control horns, one on each side of the fuselage, attached to the same wire.
Unless I take The LOSER to the next level.
That is, add sides for a built up fuselage. A weight issue, possibly and possibly not? I have to weigh some stuff. I will loose a few inches of wing area though. I'm concerned more with that than the weight, however, as you know, both are related.
I have to decide on an engion soon also.
Charles
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It's sad when a person starts a thread, asks questions, gets answers that could be beneficial to others other then them self and then feels he has the right to delete it. Nuff said.
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It's sad when a person starts a thread, asks questions, gets answers that could be beneficial to others other then them self and then feels he has the right to delete it. Nuff said.
Bill,
Thanks for the advice on flap linkages for profiles.
You're always so willing to help out.
It's appreciated.
Charles
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Ziggy gives the probability of this plane being finished only 28%.....
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Ziggy gives the probability of this plane being finished only 28%.....
Bill,
That is funny!!
And there's some truth to it.
I did say early on I loose interest quickly. I wish it wasn't this way and I'm working hard at that. Sure, I want to finish The LOSER, and do this as soon as possible. Last thing I need is to start another model. I'm low on wood.
What do you think Bill, is The LOSER shaping up? Think it's a nice design?
Charles
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[quote author=Dennis Moritz link=topic=29079.msg281638#msg281638 date=1351802182 Filled.
I just remembered that I'm currently installing these controls in a Tanager wing. I hope the picture bellow is useful.
[/quote]
Seems like a lot of extra work and extra weight for nothing.
Larry, Buttafucco Stunt Team
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Not much work really. I find it hard to believe that you use z-bend wires, Perfect aluminum cranks and a plywood mounting platform. H^^ I am chuckling. Why would you say something so obviously wrong. This mount is conventional for a stunt plane. Seeing your posts over the years, I gather that you have built many.
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I have seen many different ways of doing controls. Some folks even making up the bellcranks from scratch. It's easy to get obsessive. On the other hands bullet proof controls, that don't hang up, are adjustable and convey forces without slop, definitely essential for good performance. In my club folks do it differently. This includes the top builders and fliers who finish high at the NATs. I came to the system I illustrated through a process of evolution. It is easy to fabricate and meets the above criteria. No weight penalty far as I can tell.