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Building Tips and technical articles. => Building techniques => Topic started by: frank carlisle on September 04, 2010, 01:43:59 PM
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I made this stooge up this afternoon. I really need to get in more flights but I can't always find someone that will go out to the club with me at RCCD.
I made up this stooge from a broomstick, some dowel rod and some 3/16 ply I had laying around.
I realize that it is primitive but if it works good I could always make a new and fancier one.
I have a couple gutter spikes I'm using to nail it to the ground.
I had it outside a little while ago and pull tested it. It looks like it will work fine. Hey, I'm betting an airplane on it. y1
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Now thats pretty darn cool Frank. I just may steal that idea. I use the type that goes thru a loop in the tailwheel wire and am not all that happy with it. Yours would be much easier to use.
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I like it. Now maybe I can come up with something similar for my P-39. H^^
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Now thats pretty darn cool Frank. I just may steal that idea. I use the type that goes thru a loop in the tailwheel wire and am not all that happy with it. Yours would be much easier to use.
The ground clearance on a tail dragger wouldn't give this typr stooge enough room to work. The bottom of the fuselage on my trike is 4" off the ground.
I still tie string to the tailwheel of my taildragger.
Doc--I'm sure you'll come up with something even better. The stooge is basically a wish bone or tuning fork with a pivot and a stop.
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Looks good, Frank, and should work well! I have one similar that I built abut 15 years ago. it worked real good.
Wrap your dowels that catch the tail with some foam rubber.
Big Bear
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Looks good Frank, but judging by these pics I'd be a little bit nervous about the "arms" not being tall enough, especially if you're in the grass. If the plane happens to wiggle just enough from a gust of wind or some prop wash effect it could slip over the arms while you on your way to the center.
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Wayne--I'm nervous about the whole thing. Jan is going to be with the plane when I test the stooge today. I have the arms set so that they are slanted back to keep the plane from climbing over them.I'll let you know how it goes this evening. Matbe I'll get a video of a launch.
I just took a couple pics that will show the slant the arms are set at.
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http://www.youtube.com/user/frankcarlisle#p/a/u/0/ThQyS_vvqV4
The link above will take you to a short video of a launch using the new stooge.
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Frank,
It looks like the tail jumped a bit as the stooge released. Should not be a problem normally but you may want to take care when using it with low prop clearance.
John
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John, I think what you saw was the nose gear sitting back onto the ground. The combination of thrust and stooge make it lift a little. I think. I'll have to get more video to study. From 60 ft. I can't see what happens real well. But what are you talking about that for? You're supposed to reply here and tell me how clever I am. y1
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O Frank you are so clever.
I can see that much longer dowels, as wwarbird suggests, might cause the tail to lift significantly as it rode up the pivoting-downward dowels. Looks like your short ones are just the ticket.
You haven't shown us the trigger mechanism...trade secret?
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John, I think what you saw was the nose gear sitting back onto the ground. The combination of thrust and stooge make it lift a little. I think. I'll have to get more video to study. From 60 ft. I can't see what happens real well. But what are you talking about that for? You're supposed to reply here and tell me how clever I am. y1
Frank,
You are so clever it is an honor that you respond to my post. You are probably right about the condition. I could only see the tail though. I assume that even though the nose dropped prior to take off that everything went fairly smoothly.
John
John
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I was thinking that a kink in the two dowels would give the stabalizer a "seat" to keep it from lifting the nose before release or during the release. How you'd do that could be interesting, but that's what modelling is all about.
I'm surprised that you didn't cover the dowels with foam pipe insulation or similar. If you did that, then you could put a depression in the foam at the right spot, and solve the problem. A support to keep the tail up would keep the nose on the ground, but it looks like it works ok for practise flying. I must add, however, that practising on grass and flying contests on pavement can lead to a lot of NRQ takeoffs (too steep on the initial liftoff). y1 Steve
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O Frank you are so clever.
You haven't shown us the trigger mechanism...trade secret?
I took two more pictures just now. One shows the bottom half of the pivot arm and the second one is of the stooge in the cocked position. When I pull on the string connected to the release pin-the pin pulls out and unblocks the lower pivot arm which then releases the plane.
Ray it took two years of infrequent pondering of the stooge configuration before I began to visualize what it would look like and how it would work.Once I pictured it as a wish bone or tuning fork the rest was a piece of cake.
Anyway----do these two pix adequately show how it works?
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I was thinking that a kink in the two dowels would give the stabalizer a "seat" to keep it from lifting the nose before release or during the release. How you'd do that could be interesting, but that's what modelling is all about.
I'm surprised that you didn't cover the dowels with foam pipe insulation or similar. If you did that, then you could put a depression in the foam at the right spot, and solve the problem. A support to keep the tail up would keep the nose on the ground, but it looks like it works ok for practise flying. I must add, however, that practising on grass and flying contests on pavement can lead to a lot of NRQ takeoffs (too steep on the initial liftoff). y1 Steve
Steve--you bring up interesting points.
#1 nose dropping-----isn't an issue for me. The nose gear keeps the prop out of the dirt. I use the stooge at RCCD. Radio Control Club of Detroit. There are other modelers there but I'm leary about using someone with no c/l experience to launch. So the stooge is a basic necessity. It doesn't have to give me a storybook take off. I'm happy with it just holding the plane till I get to the handle.
#2--the kink....I'll give it a try.
#3--putting foam on the holding arms......that is also a good idea. I'll give it a try.
I'm going to head over to Home Depot this week and pick up some round and sheet aluminum stock and make another stooge-only better.
BTW--Linda will probably get mad at me when she sees that I lopped off the end of the broom. ;D
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Frank,
You are so clever it is an honor that you respond to my post. You are probably right about the condition. I could only see the tail though. I assume that even though the nose dropped prior to take off that everything went fairly smoothly.
John
John
That's much better John. You're my BFF! Yes, things went smoothly after I pulled the string. The nose dip didn't affect the take off at all. I had good line tension and the plane rolled out smooth and steady.
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Looking at the video, I can see where the nose may be up a little. The dowels are angled back a little, right. If the dowels rotate fast enough it looks like the nose is dropping back where it is supposed to be. Going to have to get busy on one. H^^
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Doc---I think that because the nose is down a little when the plane is on it's wheels it's only natural that the nose gear would lift a little in the stooge.
If you decide to build one I'd sure like to see what you come up with.
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Doc---I think that because the nose is down a little when the plane is on it's wheels it's only natural that the nose gear would lift a little in the stooge.
If you decide to build one I'd sure like to see what you come up with.
Me too! I suspect Doc's will be made out of old Fordson parts and skool crossing signs... LL~ Steve
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Frank,
I made mine out of some .046 music wire. It's a yoke that clips to the main gear wires, the ends are bent like safety pins. it forms a "V" and has an eye there that engages my pull pin stooge. The rubber band acts as a spring to "retract" the yoke like the arresting hook on a carrier plane. So far I've used it on the Ring Sportster and the Jetco Saber and is seems to work great.
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Randy--I'd thought along the same lines as you but hit a dea end when I got to the part where you keep the gear fixture from dragging on the ground. I looke close at you pix but couldn't figure out how the rubber band retracts the gear fixture.
How'd you do that?
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Frank,
You have come up with a good basic idea and design here for a trike stooge. I haven't watched the video clip yet, but this isn't something that needs to be terribly overthought. I'm not going to point fingers, but some guys WAY overthink too many things in this hobby, just wasting their own time, and that of others who don't know any better. And please, no one needs to take that comment personally. ;D
I've designed, built, and used what I call "forked" stooges of this general type. When I mentioned the arm length earlier, all I meant was a suggestion that the arms might be made an inch or so taller so the model can't jump over while you're walking out to the handle, simple as that. This was an observation based on the provided photos of this particular stooge and airplane combo. Putting "kinks" in the dowel arms won't do anything for you here except make it take you longer to build the thing, and/or design in another potential failure or "snag" point. With stooges of this type, some proper size foam pipe insulation wouldn't be a bad idea, but with it's ONLY purpose being to protect the finish on the model.
Assuming that the action of the stooge itself is completely free, light, and smooth, the model riding up over the arms during the stooges release action should be no problem whatsoever. I find that I remind myself of it all the time, more often than not the old adage "Keep It Simple Stupid", is the right way in the end. y1 ;D
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Randy--I'd thought along the same lines as you but hit a dea end when I got to the part where you keep the gear fixture from dragging on the ground. I looke close at you pix but couldn't figure out how the rubber band retracts the gear fixture.
How'd you do that?
Frank,
The rubber band simply wraps down over the bend in the gear leg and holds the yoke up. Its not rear forceful, but enough to keep the yoke from tangling upin the grass. It doesn't snap up tightly, it sort of floats there out of the way.
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Randy --- I'm going to bend some wire and try it your way. I've always stooged tail draggers with a couple screw drivers stuck in the ground with the string tied to a long 4-40 hex wrench. So I trust what you have there.
I'm very satisfied with my stooge and have plans to make another one only fancier. But your stooge is too straight forward and practical not to give it a place in my arsenal of stooges.
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Wayne---I'm a compulsive person and can obsess over even the smallest of things,like stooges, but I also have an overactive lazy bone. The stooge works and I'm done engineering it. But I'm not done thinking about it.
One thing I noticed in the video was that the tail went down and now I figure the plane probably won't jump over the holding arms. Also the nose wheel will keep the nose from dropping low enough to put the prop in the dirt. The energy generated by the thrust provides plenty of force to hold the release pin in place.
I do wonder what makes the arms flip back when the plane is released.
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No problem Frank, just trying to save us some brain power. ;D
Randy,
What plane is that in your photos? Is it the Sportster? Can we see some pictures of it?
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No problem Frank, just trying to save us some brain power. ;D
Randy,
What plane is that in your photos? Is it the Sportster? Can we see some pictures of it?
Hi Wayne,
Sure, its the Sportster, and here's a shot with the yoke "retracted too, and I threw in one ot the Saber since it was just sitting there.
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Thanks Randy! That's a couple really nice examples of cool old models you've got there. The Sabre is the nicest one I've seen, way cool paint scheme, looks just right. y1
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Thanks Randy! That's a couple really nice examples of cool old models you've got there. The Sabre is the nicest one I've seen, way cool paint scheme, looks just right. y1
Thanks Wayne, I appreciate that.
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Frank I would try to consider the fact that after take off you have a little menacing tower in the field just waiting to to get whacked by a landing plane. The design is good however you may want to evolve it to lay flat after deployment. And see if you can put some foam on it to protect the stab from dinging.
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Frank I would try to consider the fact that after take off you have a little menacing tower in the field just waiting to to get whacked by a landing plane. The design is good however you may want to evolve it to lay flat after deployment. And see if you can put some foam on it to protect the stab from dinging.
The solution here is to place the stooge on the outside radius of the circle, then after takeoff you move to the center of the cricle and the stooge is out of the way. You still need to watch out for the line, I use 3/16 white nylon, highly visible in the grass.
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Yep, what Randy said.
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Randy, I like the yoke system. It is so simple why didn't I think of it. H^^
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Randy, I like the yoke system. It is so simple why didn't I think of it. H^^
Probably 'cause my mind is simpler then your's!!??!!
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I used Randy's trike stooge all day long with confidence.
I'm abandoning my stooge.
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I used Randy's trike stooge all day long with confidence.
I'm abandoning my stooge.
Wow Frank! What a cool endorsment, I think from now on I'll call it the "Ryan Trike Yoke" Thanks
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Randy---It's a real workable solution to not having someone to hold the plane. I used it at RCCD. There were lots of people around but I was the only c/l flyer so the "Ryan Trike Yoke" saved the day.
Now I wonder how it would work on a trike with wing mounted gear?
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I use a similar kind of yoke, but capturing the wing, to launch my gear-less combat wings. Attached to the end of my flight box so the plane rests on the box and the nose (and prop) hangs out in front. Works pretty well.
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"Now I wonder how it would work on a trike with wing mounted gear?"
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When I get a round toit I will let you know. LL~ LL~
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Hi Randy, What did you cover your Sporters with? It looks great.
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Michael,
The Sportster is covered with dyed silkspan and Brodak clear, the white is Rustoleum.