Author Topic: If you like dem bones... - even more pics (Read 19173 times)

Randy Powell · « **on:** July 26, 2009, 10:33:44 PM »

OK, here's a couple of shots of progress. Fuse box is done and the wing is partially framed. Need to install the gear blocks and controls before sheeting. I'm adding some additional juice to the spar. The previous plane was a bit too flexible and I don't want another episode of the entire wing shattering because of a gear mishap. It's coming out pretty well.

Oh, the wing was mostly built today. The ribs on one side were dropped on on Friday evening (and all the alignment issues resolved). The rest was done today.

Matt Colan · « **Reply #1 on:** July 27, 2009, 06:00:52 AM »

Randy, that wing looks like a take off an I-beam wing, but with a Warren Truss style layout. Care to shed any light on that?

Randy Powell · « **Reply #2 on:** July 27, 2009, 01:05:00 PM »

Hi Matt,

It's based on the Tom Morris Millennium Wing construction design with some quirks I've added over time. I keep tinkering with the structure and process. The jig is one I've used for many years; sort of an adjustable version of a Lincoln Log jig. Of course, the aerodynamics are all mine.

Gary Anderson · « **Reply #3 on:** July 27, 2009, 01:25:29 PM »

Hi Randy,

The fuse and wing looks great. Just a dumb question, bye the picture it looks like the wing jig is a piece of press wood with a Formica covering. I've used press wood that was cover with Formica and it seemed to work out well. Just have to be sure everything is level. I used to get a lot of piece from the different job sites, when I used to do the dirty deed and go to work. Just curious, thank you Gary

Randy Powell · « **Reply #4 on:** July 27, 2009, 02:23:11 PM »

Gary,

It's 3/4" shelving material. Formica covered. The base is bridged up and squared with a laser level.

Gary Anderson · « **Reply #5 on:** July 27, 2009, 02:46:24 PM »

Quote from: Randy Powell on July 27, 2009, 02:23:11 PM

Gary,

It's 3/4" shelving material. Formica covered. The base is bridged up and squared with a laser level.

Hi Randy,

That's what I've used. Have you ever tried using a grid mat laid on top to help square items??? It helps as a quick reference. I do dumb things?

?? A lot of times I just redraw on good old butcher paper, cause its nice and white, easy for me to see, and use for lay out. Just another stupid thing I do. I use the adjust-o-wing jig sometimes. Sometimes I just surround the wing with good old angle iron and use pins about every two inches and glue it to the angle iron. Yes I laser the angle so its level and I use a good old square on the frame work. I use this method when I'm building a shark 45 wing. Don't know why, it just seems to work for me. I'm finda cheap, ha ha. I get the angle iron free?

? Just some of the dumb things I do. Thanks for your response, Gary

Randy Powell · « **Reply #6 on:** July 27, 2009, 04:49:56 PM »

Gary,

I draw reference lines on the base and match up the photocopy of the wing from the plans and build over that.

Edit~~~

Just thought I'd note that this plane won't get much more work done over the next couple of weeks. Busy week at work and I'm going on vacation next week. I'm going to go bug Pat Johnston and Eddie Culver in Idaho.

Larry Wong · « **Reply #7 on:** July 29, 2009, 06:19:40 PM »

Randy it looks like a great start as always, better hurry it's paint weather ( no rain) !

Randy Powell · « **Reply #8 on:** July 30, 2009, 10:24:02 AM »

Larry,

Yea, too bad it's hiatus time. It's a 120° in the shop. Yikes! And I'm taking off on Saturday for vacation. Sigh...

It should be a good plane if I can keep my finger off the paint trigger.

Randy Powell · « **Reply #9 on:** July 30, 2009, 12:48:02 PM »

Ty,

Well, in Pat's case, those pants are pretty low to the ground. Might have to be a slap to the side of the head. I can reach that.

I'll say hi to Eddie.

Randy Ryan · « **Reply #10 on:** July 30, 2009, 12:56:56 PM »

Dem Der's nahce bones Randy, real nahce.

Randy, PMed ya'

Randy Powell · « **Reply #11 on:** July 31, 2009, 10:21:46 AM »

Randy R and I have been discussing wing construction theory. It's interesting.

Just a side comment: Pat Johnston and I have discussed wing construction for years. He is of the camp that you select the lightest wood you can and build with standard construction methods. He favors the standard "D" tube wing layout. The advantage of this is that the construction is simple (Pat likes the tubes on blocks construction method ala Al Rabe) and having a laser cutting in your garage insures that this method will be straight every time. A nice thing to have. It's a lot tougher to get a dead straight wing every time if you have to hand cut the ribs and more importantly the jig holes.

My feeling has been that lightest wood isn't always available or even necessarily desirable and that wood should be selected carefully to fulfill various jobs. That in conjunction with judicious use of carbon fiber can make for a ridiculously strong wing that is of an acceptable weight. I tend to buy a range of wood from as light as I can get my hands on to some pretty hefty stuff. Even some 15lb stock I have has it's place. So I tend to design structures to take advantage of various wood's weight, strength and grain. A rib that is from super light 4lb stock 1/8" stock isn't going to be any lighter than the same rib made out of 1/16" heavier 8lb wood and may be more sound structurally. So I tend to come up with structure designs that can use heavier wood. take advantage of this additional strength they offer and still be light. Takes a bit more effort and time to figure it out but I think it's worth it. But I've learned as I've gone along. So at this point, I can build a wing that is constructed with wood that covers a pretty wide range of grain type and weight with each piece set up to do a specific job and the wood selected accordingly. It's not as simple as Pat's approach, but I'm also not tied to always getting the lightest wood possible. I don't know that one method is better than the other in application, but each has it's advantages and drawbacks.

Besides, it's fun figuring this stuff out and it looks cool.

john e. holliday · « **Reply #12 on:** August 02, 2009, 07:26:33 AM »

To me the D tube wing is easier for most modelers as far as construction. I used to think that until I built my first I-beam wing. On a true I-beam you have to construct the fuselage first. Then build the wing. I can also use the harder wood for the ribs in an I-beam. Randy you are an artist with that wing construction. Have fun, DOC Holliday

roger · « **Reply #13 on:** August 02, 2009, 12:37:45 PM »

and now ladies and gents the flying skelton

roger · « **Reply #14 on:** August 02, 2009, 12:40:57 PM »

yall got more sticksin thar than a popcycle factory

Bryan Higgins · « **Reply #15 on:** August 02, 2009, 04:43:41 PM »

Hi Randy

Always like to see your building skillz. Very clean and thought out designs.
I am waiting for my custom built wing and fuse jigs from Jim Snelson from
www.clcentral.com .
Then i too will be creating a master piece wing design that people will use
through out this world winning championship after championship.

Just kidding, just seeing if you guys are awake

Thanks Randy for sharing.

Randy Powell · « **Reply #16 on:** August 12, 2009, 11:49:26 AM »

WEll, I got a bit further along. I had a moment with the landing gear layout. I had to machine the LG blocks (I didn't have any gear block material or any 3/4"x3/8" stuff around weirdly). So I took a piece of pretty hard exotic scrap I had laying around (I think it's Zebra wood, but it could be something else) and machined a couple of piece of that into blocks. Decided to beef up the landing gear setup a bit after a couple of planes that suffered catastrophic wing failure after a hard landing. Spar was fine for flying, but couldn't take that lateral beating from a bad landing. Breaking out the landing gear blocks is one thing, tearing out half the spar is another.

So, got that done and after a little messing around, managed to get in a solid landing gear layout that isn't overly heavy. Am now putting the controls in and after that I can start get it sheeted then on to over stuff. This won't be the lightest structure I've ever built, but it will be a very good compromise between weight structural rigidity. I'm guessing the all up weight of the wing with control but no flaps will be in the 8-10oz range. Probably toward the lower end. While not stellar, certainly in the ball park.

I'll post some more pics after I get the controls in. They will be interesting.

Matt Colan · « **Reply #17 on:** August 12, 2009, 02:25:08 PM »

I was just wondering if there was any update, and now I stopped wondering. Looking foward to the pictures

Randy Powell · « **Reply #18 on:** August 16, 2009, 09:17:47 PM »

OK, Matt, here's a couple more pictures. The first is the wing almost ready for sheeting on the bottom. The pieces near the trailing edge are new of this structure. I added the rest then sheeting. The bottom pic is the wing sheeted and ready to come out of the jig (finally). I weighed it and without the flap horn and before peeling off the jig tabs and shaping the leading and trailing edge, it's under 7oz. Figure somewhere under 10oz for completed wing with tips, hardware (slider and tip weight box) and flap horn.

Claudio Chacon · « **Reply #19 on:** August 17, 2009, 08:38:55 AM »

EXELENT Randy!
I always follow your building sequences closely.

Best regards

Claudio.

Randy Powell · « **Reply #20 on:** August 17, 2009, 09:08:35 AM »

Hi Claudio!

I've been told that my structures are over-complicated. I suppose. It's a logical process and not very difficult, though it can be tedious to build. This wing was built to this point (pretty much done) in 4 building sessions. Not sure how many hours since I tend to work on the wing, then work on something else then come back to the wing, etc.

Each time I build one of these, I analyze what I end up with as far as compression, tension and torsion resistance. I keep reducing the amount of structure until it starts to flex in certain areas, then I put some back. At this point, I've pretty much got it down, though I do keep trying out new ideas that will maintain (I hope) the rigidity while reducing the amount of wood used.

I like this type of wing because it's not very hard to build, comes out of the jig straight every time and is pretty light.

john e. holliday · « **Reply #21 on:** August 17, 2009, 02:12:57 PM »

Too bad you have to cover all that gorgeous structure with paint. Have fun, DOC Holliday

Claudio Chacon · « **Reply #22 on:** August 17, 2009, 03:49:00 PM »

Quote from: Randy Powell on August 17, 2009, 09:08:35 AM

Hi Claudio!

I've been told that my structures are over-complicated. I suppose. It's a logical process and not very difficult, though it can be tedious to build. This wing was built to this point (pretty much done) in 4 building sessions. Not sure how many hours since I tend to work on the wing, then work on something else then come back to the wing, etc.

Each time I build one of these, I analyze what I end up with as far as compression, tension and torsion resistance. I keep reducing the amount of structure until it starts to flex in certain areas, then I put some back. At this point, I've pretty much got it down, though I do keep trying out new ideas that will maintain (I hope) the rigidity while reducing the amount of wood used.

I like this type of wing because it's not very hard to build, comes out of the jig straight every time and is pretty light.

I like your approach a lot Randy. It is a "blend" of the most proven wing building methods and looks like it takes advantage of the pros of each system -I-Beam/Warren Truss/C-Tube- with some carbon fiber to add a bit of high tech flavor. A very innovative way to build a wing, indeed.
That's one of the great aspects of this hobby: there's always room for innovation and improvement.

Just one remark: post MORE pics!!!

Matt Colan · « **Reply #23 on:** August 17, 2009, 03:52:13 PM »

Quote from: john e. holliday on August 17, 2009, 02:12:57 PM

Too bad you have to cover all that gorgeous structure with paint. Have fun, DOC Holliday

But think how well it'll turn out knowing the artist that randy is!

By the way, that wing look really good!

Randy Powell · « **Reply #24 on:** August 17, 2009, 11:07:30 PM »

Thanks guys. I have an idea for the finish. I'm gonna have to see if I can talk Shultzie into some help, though.

Claudio, I have a bunch more pictures, but I didn't want to bore folks. I thought these gave the flavor. I can scare up some closer shots, though.

Claudio Chacon · « **Reply #25 on:** August 18, 2009, 05:48:46 AM »

[quote

Claudio, I have a bunch more pictures, but I didn't want to bore folks. I thought these gave the flavor. I can scare up some closer shots, though.
[/quote]

You're not going to bore me...that's for sure!

Matt Colan · « **Reply #26 on:** August 18, 2009, 06:41:53 AM »

Or me!

Bill Little · « **Reply #27 on:** August 18, 2009, 09:42:55 AM »

Hi Randy,

I love to see your construction pictures, too! You have some neat construction ideas that work, and I envy your patience on building these wings.

Mongo

Randy Powell · « **Reply #28 on:** August 18, 2009, 12:16:49 PM »

OK, then here are a couple more.

The first is the rib cutting jig. (also has the bellcrank on the side there)

The second is a shot of the bellcrank installation. It's pretty beefy (as is the bellcrank - not going there again). The plywood plates are tied to the center plywood section of the spar and the upright pieces will tie directly to the fuse sides (ideat stolen from Al Rabe).

The last is the initial setup for the stab core. I'm going to use a core and sheet setup for the stab that should work pretty well.

I tend to work on one assembly until I'm tired of looking at it then move to another assembly. so stuff gets a bit scattered around.

Randy Ryan · « **Reply #29 on:** August 18, 2009, 01:27:03 PM »

Randy,

Do you run that little shear web between the spar and LE sheeting full span?

Randy Powell · « **Reply #30 on:** August 18, 2009, 02:52:35 PM »

Randy,

Not this time. Just out past the gear mounts. It's just supports and diagonal bracing past that.

Claudio Chacon · « **Reply #31 on:** August 18, 2009, 04:21:17 PM »

Quote from: Randy Powell on August 18, 2009, 12:16:49 PM

OK, then here are a couple more.

The first is the rib cutting jig. (also has the bellcrank on the side there)

The second is a shot of the bellcrank installation. It's pretty beefy (as is the bellcrank - not going there again). The plywood plates are tied to the center plywood section of the spar and the upright pieces will tie directly to the fuse sides (ideat stolen from Al Rabe).

The last is the initial setup for the stab core. I'm going to use a core and sheet setup for the stab that should work pretty well.

I tend to work on one assembly until I'm tired of looking at it then move to another assembly. so stuff gets a bit scattered around.

Randy,
What kind of socket head bolt do you use in the bellcrank for the ball-link? 4-40 or 6-32? In any case, is it a normal grade one or stronger?

Thanks for the extra pics!

Randy Powell · « **Reply #32 on:** August 18, 2009, 11:18:49 PM »

Claudio,

It's a socket head, button screw with shoulder. The shoulder fits pretty well in the ball link. They are grade 8 screws. The pivot is a piece of 1/4" brass tubing and the bearing through the bellcrank is bronze. Not the most elegant layout, but after having a bellcrank fail on the last plane, I've become a belt AND suspenders kind of guy.

Oops, should have said, the screw that hold the ball link is a 4-40.

Allan Perret · « **Reply #33 on:** August 19, 2009, 07:38:49 AM »

Would like to see some more details on how you made those line terminations at the bellcrank.
Not to crazy about the .25 brass tube pivot, have you used that before ?
Is it the regular K&S thin wall stuff or something else with a thicker wall ?

Claudio Chacon · « **Reply #34 on:** August 19, 2009, 08:59:32 AM »

Quote from: Randy Powell on August 18, 2009, 11:18:49 PM

Claudio,

It's a socket head, button screw with shoulder. The shoulder fits pretty well in the ball link. They are grade 8 screws. The pivot is a piece of 1/4" brass tubing and the bearing through the bellcrank is bronze. Not the most elegant layout, but after having a bellcrank fail on the last plane, I've become a belt AND suspenders kind of guy.

STRONG is the key word here, and this one will not fail.

I'm curious also about the line terminations. Please post a close-up of the BC assy when you have a moment.
Thanks.

Bill Little · « **Reply #35 on:** August 19, 2009, 11:28:02 AM »

I will venture a guess and say that Randy wrapped the line terminations and covered it with heat shrink tubing. I am sure Randy will correct me if I am wrong.

Big Bear

Randy Powell · « **Reply #36 on:** August 19, 2009, 08:52:18 PM »

Hmm, let's see. The bellcrank was made in a mold from West Systems 105/209 epoxy and post cured. I cut the slot in on the end with a mill. The terminations on the leadouts are made from some 1/8" PC board I've had around forever and the slot around the perimeter was cut with a slotting bit on the mill. The screws are standard 4-40 hex head cap screws 1" long with a 3/8" shoulder that the PC termination rides on. The leadout are wrapped with 28 gauge stainless wire and heat shrink tubing over the top. The leadout wire going around the fitting is dressed with some acrylic polymer that dries fairly hard, but retains some flexibility. The point was to insure the wire didn't jump out of the slot. Makes for a very smooth movement. Oh, almost forgot, the PC board pieces have a bronze bushing in the middle that the shoulder bolt actually rides on.

The center pivot is a thick wall 1/4" OD brass tubing I had hanging around. Much heavier than the K&S stuff. A number of years ago, I bought a box of brass scrap from a place I get aluminium and such from. He has a small box with all kinds of scrap pieces. Tubing, sheets, angle, whatever. There was a lot of tubing in the thing and I dig around in it when I'm looking for a piece of brass. The bearing in the bellcrank (that you can barely see under the JB Weld) is a chunk of bronze 1/4" ID tubing. The little collars that was soldered on the top and bottom are to retain the bellcrank. That was some thin walled 1/4" ID brass tubing that might be K&S. It didn't come from the scrap box. But all it does is retain the crank in position.

All and all, it's a very smooth system and I'm pretty sure, unlike the system in the poor Ringmaster Deluxe, that it will hold up just fine.

Speaking of that, my buddy Pat Johnston, surprised me when I was recently in Idaho with a nice, new set of plans for the RD (with corrections I suggested) and a set of laser cut ribs. so I suppose when I'm done with this project, I'll build another RD with a much betting bellcrank - probably like this one.

Claudio Chacon · « **Reply #37 on:** August 20, 2009, 04:58:25 PM »

Terrific unit Randy. Those line terminations are the best I've seen.
Now I know that I'll never have one of those nice pieces, unless someone sells them...no mills around my workshop

I stay tuned with the updates...
Thank you.

Allan Perret · « **Reply #38 on:** August 21, 2009, 08:00:10 AM »

You don't need a mill. You could make the part from a 3-layer lamination of 1/32" phenolic (micarta) sheet, with the middle lamination smaller than the other 2 to produce the groove. That would give you a groove of .032" which is just about right to accommodate the leadout cables.

Same method could be used to fab up a bellcrank with the forked ends with having to mill the slot for the forks..

Allan Perret · « **Reply #39 on:** August 21, 2009, 08:37:24 AM »

Hey Randy:
Got a couple ?? on dem wing bones.

Thickness on the rib strips, looks like at least 1/8, maybe thicker?

Do you have 2 different rib templates, one for the angled ribs and another for straight half ribs, or do you use the same template for both. I know its a very small difference between the 2. I would think that you are using the same template and leaving a little fat and then sanding them all even with a long straight sanding bar ??

As the ribs get shorter out to the tip, from where do you trim off the excess length of the ribs; front, back, or both ? I've never built an I-beam..

Main spar, is it parrallel to TE or does it sweep back to follow the airfoil high point ?

Randy Powell · « **Reply #40 on:** August 21, 2009, 09:05:52 AM »

Allan,

It's the same rib template and yes, you make them a touch fat so you can use a bar to sand. The angled ribs have to be sanded a bit so that the surface you are gluing the planking to is flat. It's not much, but it is necessary to get a good glue joint.

The ribs are 1/8" sheet. The ones from the gear in are from some "C" grain 8lb stock and are fairly hard. From the gear out are from some 4lb. wood (or as I call it, "puff wood"). It (among other things I do) tends to center the weight of the wing toward the center. Much like trying to keep what Robert likes to call "concentrated weight" off the very nose and tail of a plane to avoid barbell effect, I feel like it's a good idea to keep excess weight from the tips of the wings when you can. Probably just me.

In the case of this wing, the spar is slightly swept back (about 3/8"). This is part of the airfoil design. The ribs in an I-Beam wing are usually trimmed from the rear all the way out to the tip. In the case of this wing, it is a 20% airfoil at the root and 12% at the tip. The ribs are trimmed from both the front and rear to maintain the vertical taper and the high point of the wing where I wanted it all the way out to the tip. The airfoil was maintained by using a guide used while dropping on the ribs. I think if I had to do a wing like this again (with the sort of taper I used), I'd just browbeat Larry Cunningham into giving a new copy of the StuntRib program and do the ribs that way. The constant measurement of the taper as ribs were dropped on was a pain. I ended up tossing about 20% of the ribs I cut with the jig because due to mis-cutting them when I went to drop them on then checking with the guide and finding out that I cut the front too much and missed the taper point. While the way I did it worked, it made things more difficult than they had to be. But it's together now and looks pretty good, so I'll quit whining.

Hope that answers the questions. This isn't a true I-Beam. It's a variation on Tom Morris's Millennium Wing.

Shultzie · « **Reply #41 on:** August 21, 2009, 02:59:25 PM »

Hey..Randy!!!
Love dem'bones...Dat is da

word of da Lord.

Claudio Chacon · « **Reply #42 on:** August 21, 2009, 04:51:32 PM »

Quote from: Allan Perret on August 21, 2009, 08:00:10 AM

You don't need a mill. You could make the part from a 3-layer lamination of 1/32" phenolic (micarta) sheet, with the middle lamination smaller than the other 2 to produce the groove. That would give you a groove of .032" which is just about right to accommodate the leadout cables.

Same method could be used to fab up a bellcrank with the forked ends with having to mill the slot for the forks..

Hey, that is a very good idea!

Have you tried this before?

Allan Perret · « **Reply #43 on:** August 21, 2009, 06:32:42 PM »

Quote from: Claudio Chacon on August 21, 2009, 04:51:32 PM

Hey, that is a very good idea!
Have you tried this before?

Not for this particular component, but I have used this method in other applications.
Adjustable lead guides, its easier and more accurate to build the slotted part out of 3 layers of 1/8" spuce than it is to cut the slot. Makes a nice smooth slot for a 4-40.
Trailing edges, I make the middle lamination out of 1/32". Leave out the middle lamination where you need hinge slots, then you dont have to cut them. You can make it double wide, them cut it down the middle for perfect alignment of the hinge slots. Use one part for the TE and the other for the forward part of flap. I use this also for the stab and elevator hinge line parts.

Ever since I saw Brett's laminated bellcrank with teardrop leadout terminations, been thinking about doing one myself. If I ever do it that's how I would do the teardrops. I already have the phenolic. I keep assorted thicknesses on hand, very useful material. I use 3/32" or 1/8" for motor pads instead of aluminum.. And make profile tank mounts from 1/16"

Randy Powell · « **Reply #44 on:** August 23, 2009, 12:29:47 AM »

Allan,

Yea, there are other ways to go about some of this. I have a mill, dp and bandsaw so I do a lot of stuff that some guys can't do. It's no big deal for me to just hack it out with the mill.

Here are a couple more pictures. The first is a pic of the stab. Came out a bit heavier than I had planned at 1.25oz. That's OK, though. It makes up for that in being very, very torsionally resistant. The second is the fuse under construction. As soon as I get the blocks hacked out and fairly close, I can put the beast together. The last is the wing all ready to be mounted in the fuse (except for mounting the flap horn). I haven't done the tips yet because I'm still playing around with the proposed slider unit I'm designing. I'm not happy with the plug I made so I'm still dinking around with it.

Matt Colan · « **Reply #45 on:** August 24, 2009, 05:50:04 AM »

Lookin good Randy

Dennis Adamisin · « **Reply #46 on:** August 24, 2009, 07:07:23 AM »

...and progressing quite quickly. ANOTHER wonderful piece of work, Randy!!!

Randy Powell · « **Reply #47 on:** August 24, 2009, 09:26:21 AM »

Thanks Matt, Dennis.

Got the blocks rough carved yesterday. They are close enough to go ahead and hog them out. The molded rear top block is fitted and the bottom block is roughed out. The front top block (with simulated canopy) is pretty much done. Just getting ready to fit up the wing to the fuse after dinking around the the control system for quite a bit. A bit of mixing and matching there to get a smooth layout.

I'm going to do some interesting stuff with the cowl on this one. Just being silly, I suppose, but I had an idea to get a better fit than normal and I will try it out.

Claudio Chacon · « **Reply #48 on:** August 24, 2009, 09:39:01 AM »

Randy,
Which is the weight of the completed wing before covering?

Randy Powell · « **Reply #49 on:** August 24, 2009, 09:49:41 AM »

Claudio,

As it sits there in the picture, it's something under 8oz. But it doesn't have the tips or flap horn on. My guess is it will be a bit under 10oz when completed.

Edit

Having built similar structures several times, I'm pretty good at guessing all up weight prior to finishing. My best guess at this point is the airframe, with engine and accessories, ready to fly but prior to finish will be in the 38-40oz range. This gives me a finishing budget of 10-12oz. If I can keep my finger off the paint trigger, that should be pretty easy to make with a 600 square inch wing.