Wing Parts Aft of the Rear Spar

Wing Template Use
You received a plywood wing template that is cut in the outline of the upper surface of the wing. This is your guide for establishing the correct profile for everything that will be attached to the rear of the wing. This includes flaps, ailerons and, in this case, the root and tip ribs. If you utilize the template for alignment, you’ll find everything is nicely lined up and the airfoil is accurate.
Root Ribs
Attaching the root ribs is quite straight forward, although there are several possible peculiarities
depending on when your kit was produced. The shortening of the bottom stiffener has been mentioned, but we’ll discuss it again in relation to the root rib. Briefly, in a few airplanes, the bottom flap bay stiffener is 3/4” too long and must be shortened to allow attaching the root ribs. Use the wing template to align the root rib and clamp it against the vertical stiffener in each of the root rib positions. Drill four #40 holes through the rib and the angle that’s riveted to the rear spar. Before drilling, make absolutely the rib is flush against the wing template.
Cleco both ribs to the spar attach angle and slide the pre-bent aluminum skin over the ribs and under the skin and above the flange. Notice on Drawing 2 that the rivets between the two root ribs going through the skins and the spar are AN426-4’s, NOT AN3’s.
On some older kits, if the supplied metal is flushed to the fuselage-side of the root ribs, it hangs into the flap bay by about 1/4” and partially covers one of the holes in the lower rear wing skin. If this happens, slide the sheet metal toward the middle of the airplane enough that it is flush with the flanges of the root rib in the flap bay and clamp it in place in preparation for drilling the rivet holes. Use a rivet spacing fan to layout an even row of rivet holes. After they have been drilled, remove the ribs and the trailing edge skins and debur and dimple all holes.
Trailing Edge Tip Rib
Because it is rather fragile, you can hold off installing the outboard, trailing edge rib until much later, when you’ve riveted down the top skin of the wings and are ready to install the wing tips. The wing tips will protect the trailing edge rib. An alternative is to install it temporarily by clecoing the wing skin down and drilling all of the tip attach holes in the ribs, skin and tip, so the wing tip protects the rib. Then remove it until ready to close up the wing. Regardless of which direction you go, install the tip rib the same way you did the root ribs: use the wing template to guarantee proper alignment and fit the fiberglass wing tip to the tip ribs, not the other way around.
The supplied plywood template is the key to establishing the vertical placement of both the ailerons and the flaps.

Left wing root. Notice how the bottom skin stiffener abuts the flange. You’ll use the plywood template for aligning the ribs.

Pressing Ribs and Fluting without Pliers

Source: 2016 Beartracks, Chris Owens

When it comes to transforming large sheets of aluminum rectangles into airplane-shaped parts, every builder seems to have a way that works best for them. I think I may have tried them all, or at least some variation of them. But no matter how I tried, I just couldn’t get them to look as nice as a set of factory-built ribs from Mark Goldberg and our great friends at Bearhawk Aircraft. I kept telling myself that there had to be a better way to form wing ribs that would yield consistent results and not induce arthritis along the way.
After a lot of head scratching, YouTube-ing, and following in the foot-steps of those who have forged the trail before me, I adopted a number of different techniques to create a beautifully-crafted set of wing ribs that look as though they could have come from a factory press. I’d like to share the story with you. Much of the process is “the usual”, but the finishing stage brought out the best in them.
It begins with the usual tale of creating rib forms from the master template that comes with the plan set. Mine were from MDF— pretty much by the book if you have Eric Newton’s construction manuals. Trace the pattern on the sheet, rough cut (with an electric sheer, in my case), and stack them up.



I chose to use the router method to make sure that each rib blank was flat and identical. Bolting several of the blanks into the form, predrilling the lightening holes, and cutting off the excess out-side material with the band saw, the ribs were ready for the router. I chose a tall Bosch Model # 85601MC carbide laminate bit that I sourced from Lowes for about $25. At 1/2 inch diameter, 1-1/2 inch cutting length, and with a 1/2 inch shank, the beast can chew through a lot of aluminum at once.




Lather, rinse, repeat several hundred times, and you’ll eventually have yourself a lovely collection of wing ribs. And they’re all uniform and beautiful.

Many of us have made it this far and have these lovely trophies to show for it. But what comes after this stage can make or break you as it is very easy to destroy the time and hard work you have dedicated to these parts. I tried a few different ways to flange lightening holes and flute the edge flanges of my wing ribs, and I really buggered up a lot of parts. The Bob Stick and fluting pliers just weren’t getting me where I personally needed to be. I was not creating straight parts. I’ll spare you the carnage of the war zone photos. But note that it wasn’t pretty.
Fast forward to better days, I’d like to show you a technique I adapted from fellow Bearhawk Patrol builder John Snapp, as well as a Hummelbird builder, that creates beautifully-formed lightening hole flanges, complete with perfectly-spaced flutes and fabulously flat edge-flange surfaces through which one would be eager to drive a rivet.
Starting with the lightening holes, I routed a 45-degree edge around the circumference to allow a place for the rib hoes to stretch into. Armed with a 20-ton Harbor Freight press with an air-over-hydraulic ram installed, a piece of 1/2-inch steel plate, and some “cow mat” from my friend’s dairy barn, the lightening holes were effortlessly pressed into the ribs. You can see by the photo, it’s a precision event, as a retired university Biology Professor, a Dairy Farmer, and a Mechanical Engineer oversee the operation while I stealthily snap a photo. For details on this technique, visit John Snapp’s YouTube channel at https://www.youtube.com/user/n3uw



The lightening holes were the easy part. Just do it several hundred times, and there are a lot of very nicely-flanged openings. The edge flanges are the bits that always ruined parts for me. So I wondered how I was going to make this work better. I started out with some long oak planks that I sourced from the Aviation Supplies aisle at my local Menards, and traced the master wing form onto it. After cutting it to shape with the band saw, sanding it to form with the disc sander, and relieving the edges for bend radius, I drew the lightening hole and rivet locations onto the form board. The flutes go in between the rivet locations, of course. So I chucked up a 1/4-inch straight-cutting bit in my router table, and then I routed a slot into the edge of the form, in between the rivet locations. Then using a sanding block I rounded over the edges of the slots for a smooth transition between the surfaces.


This is an important step, because I am going to using a tool to force the flange surface down into the slot to form the flutes. If the corner isn’t relieved enough, the aluminum will tear as it is being forced down into the slot.
After creating a backer board of the same material, I routed circular holes in the surface to allow for the lightening hole flanges in the ribs from the previous step. I bolted each rib between the two pieces, and then hammered over the flanges with a soft hammer, up until they were about as flat as they could get.


Using the soft hammer and a screwdriver with 1/4-inch shank, I stretched the metal into the fluting slots with a firm tap. It doesn’t take a whole lot, and usually one tap will do the trick on the .025-inch material. It might take two if you are fluting the .032-inch center ribs.


When the ribs come out of the flanging form, they will be a little bit bowed up, since the spring-back of the aluminum keeps it from being perfectly straight. Using a technique that Vans builders have had at their disposal since the dawn of time, I created a flange-bending tool with a 13-degree undercut. Squeezing the flange bit-by-bit with this tool will straighten the flanges up to 90 degrees. It might take a couple of tweaks with some fluting pliers to get them exactly right. As you can see, it works great for nose ribs, center ribs, and others that need fabulously flat edge flanges. I couldn’t be happier with the results!




For greater detail, please check out my forum posts on the subject at http://bearhawkforums.com.

Drilling Stiffeners to Ribs, Sharpie in the Drill Press To Mark Where they Go

Source: 2016 Q3 Beartracks, Mark Johnson
img_20140927_152423791 To drill the rib stiffeners onto the ribs, I started by be-coming a father.
There is no such thing as a perfectly isolated project; life’s departments simply overlap too much. I knew that would be the case when as early as 2013, I started contemplating a homebuilt. I knew I’d be distracted, I’d be learning, I’d be slow, and maybe I’d be just plain bad at it. But I started small and for whatever reason, I now find myself drilling rib stiffeners onto center ribs. It’s come to this.
The plans say “these go here and here” but reality says “you will start by stressing about the weather getting colder, then you’ll go back and forth with the wife about weekend expectations, job security will get very interesting at times, you will waste hours cleaning a metal brake that eventually you will not have access to, you will feel deathly ill, help start a soaring club, and then fix a plotter for the guy who’s teaching you to weld… oh and by the way, these angles go here and here.” Where is all that extra detail in the plans?
So, there are skills required to build a plane, and there are skills required to get you to the point of being able to build a plane. Here’s how I approached the latter, beginning with time management. I’m a full time husband, father and engineer, and resident of a beautiful place that begs one to do anything but work. All of these compete with the garage, but not in the wee hours of the morning. If I can crow-bar myself out of bed, that chunk of time is all mine. I’m effectively a single retired empty-nester be-tween the hours of 5 and 7 am. 1-2 hours a day ~ 10 hours / week, 500 hours / year… 10 years may-be?? That’s as good a target as any. Consider 168 hours in a week. Take 2/3 out for work and sleep, and all the other stuff gets 56 hours — whether it be going to the park with the fam or writing this article. The time is there, one just needs to see it and prioritize.
Moving on to money management. Fabricating everything certainly helps to keep monetary costs down. Things I don’t care to make – raw materials, engine, subkits and components like windshield and fuel tanks – will be larger, sudden costs that cannot be spread out over time as easily. Balancing my project’s operating cost with my ability to put money away each month is an art, but “luckily” I’m taking forever so I don’t worry about outpacing my income. If you go the quickbuild route, you would have to save up initially (or go in debt – not an option for me). Your rate of saving must be greater than rate of value gained by purchasing the kit. Think of saving as a way of building faster: If I save $100/week and buy a $250 box of parts including $50 in materials, that box needs to save me at least 2 weeks of build time, or I might as well fab it. But that assumes the ability to save at a high enough rate.
How about motivation? That’s not in the plans either. I try to surround myself with aviation-minded folks and airplanes, but usually both center on antiques with big sparkling radials. They say to me “you’ll never be able to afford this,” making it hard to relate to my own project. But at our most recent local fly-in, with over 500 visiting aircraft, I got to see what the regular peasants flew in, and lots of it – Tailwinds, Kitfoxes, Ercoupes, RVs and Highlander-ish things. Even the gaggle of Skylanes was a nice reality check. Regular people fly. I can fly. I can create something. That Laird in the front lawn was freakin’ gorgeous, but the thing in my garage will someday be my contribution to this scene.
It is my hope that these words help motivate anyone who feels like a fish out of water when approaching a homebuilt. I don’t think my circumstances are rare, but they are rarely discussed. It’s assumed that the builder has it sorted out and that their build can be isolated from these pesky obstacles. But life creeps in and adds its flavor. I’d love to hear other perspectives and how you guys handled it.
So with that said, here’s how I drilled my stiffeners to the ribs (and you thought that was just a metaphor). This process is how I do many things:
1: Go on Youtube and see how smarter people did it.
2: Adapt it to suit my level of garage ingenuity.
Specifically, I determined the important thing was that the stiffeners were parallel to the spar webs without interfering with the flanges around the rib and lightening holes. My stiffeners were all pre-drilled (I did follow Desertbearhawk’s youtube method for that). I could eyeball the up-and-down clearance from the rib flanges. The problem was locating them all square and even.
One nice thing about a drill press is that the spindle comes down in the same place every time. If I had a fence clamped down at the right distance from the spindle, I could turn my drill press into a giant inverted sharpie holder, and slide a rib along that fence while marking the line, or at least a couple dots. The fence was moved depending on which stiffener I was working on. I ran some scrap material along the fence to match the spar thickness for a particular rib. It seems to be working. Until 7am anyway.
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Trimming Ribs to Length with a Router Table

Source: 2016 Q1 Beartracks, Mark Phillips
-005While studying to build my ribs, I learned that my ribs would have to be slightly different lengths depending on where they were positioned on the spar. It made sense to make all the ribs the same at first and trim them to the proper length later.
I used my router to make all my ribs and do the lightning holes. I was very impressed at how easy it was, and liked the results. I figured using the router to trim the ribs to length would also be a good way to go. I set the fence at 1/8” and figured I would run the piece through it twice for the ribs that needed to be trimmed ¼”, or once for the ribs that needed to be trimmed 1/8”. I bent a scrap piece of .032 aluminum and tested it. It vibrated when the bit cut through the flange but otherwise worked fairly well. It was not as smooth as I hoped, but it did the job. I started with the false ribs, and am so very happy that I did that. It chattered on the flange, which I ex-pected, but then it suddenly sucked the piece in between the bit and the fence. Since there is no medical report attached here you can tell I let it go and did not let it suck my fingers in too. You can see the damage in the photo to the right.-006
A change of plan was in order. Since the router does do a great job of cutting the piece between the flanges I did not want to give up. The method that made the most sense to me was to cut between the flanges with the router and use a sander to take care of the flanges. I used the router to cut from one mark to the other in the photo below. The photo to the right and below shows the result.
The disc sander removes the flange very well, as shown in the bottom left picture. Now it’s ready to finish on the Scotch-Brite deburring wheel.
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Forming Ribs with a Tent Stake Mallet

Source: 2001 Beartracks, Bob and Mike

One of the first tools that every builder is going to have to obtain is a rawhide or plastic mallet to form ribs with. One builder suggested the Coleman Tent Stake Hammer. We picked one up ($3.49 + tax) and found that with a little modification it is an excellent rib forming tool. The flat surface of the mallet face is fine for driving in stakes but not very good for forming aluminum. The striking face of the mallet needs to be given a slight concave surface with a bit of filing and sanding – this is a very simple task and you will find that the mallet is more than adequate for forming ribs. It is available at any department store that has a Camping Section.

2000 Beartracks Mailbag: Q&A with Bob

Bob, Enclosed is a check for Bear-Tracks for another year. I do have a few questions:

1 – What is a good method to use to transfer the airfoil shape to the wood to be used for the form block for the wing ribs?

2 – What is the recommended radius for the wing rib form blocks? I believe that 1/8″ would be about right for both .025 and .032.

3 – Do you have an e-mail address and if so do you answer e-mail correspondence?

I have a piece of 1″ thick hard maple for the form block. I just need to transfer the airfoil shape to the wood and cut it out. I am ready to start with the ribs. Is Proto II in the air? I bet the performance is really great – Thanks for your time.

Paul Foster – #289 – Monte Vista, CO

Paul, Thanks for your questions and newsletter renewal. As for your questions

1) The best method to use is to glue drawing #7 to your form block with contact cement or Plyobond.

2) a 1/16″ radius will work best for both thicknesses of the aluminum.

3) I do not have an e-mail account. Proto II is flying great -look for a flying report in this issue of Bear-Tracks. -Bob

This letter was pulled from the Bearhawk E-group. For more information on the Bearhawk E-group see page 7.

Well, after several days of non-stop building, 023 is on the main gear. I stumbled across a new Scott 3200 tailwheel in some stuff my Dad purchased from someone’s attic. He got a bunch of stuff (including a 65 hp engine, prop, landing gear, etc) for less than the price of a new Scott! What a deal.

Anyway, related to tail leaf springs, after much discussion and some consulting with Bob, I have decided on purchasing a PA25 tail spring from Univair (part number PA25TWS1) for approximately $90. 1 decided on the PA25 because Bob recommended two leafs all the way to the tail wheel bolt. Taper rod was attractive but with the Scott tailwheel, side loads should not be a big problem – it will go to full swivel if a major side load occurs.

My plan on putting a Continental 0470 on my Bearhawk has been changed. Finding an engine mount damaged or not – is not easy. Any found, even damaged, seem to run between $500 & $700. The Lycoming 0540 seems easier to make an engine mount following Bob’s newsletter. Also, Bingelis only talks about Lycomings!

Compressing the landing gear shock strut took some thought. I used a bar clamp – very long – and it worked fine. Later Bob told me he used his drill press with the table moved off center – I wish I thought of that! Oh well, some days I make things harder than necessary.

Piper TriPacer Seats also took some work to find. I ended up paying $60 each – frames in very good condition and but they need covering. Seemed like allot but finding seats was not as easy as hoped. Salvage dealers did not have any. My source has a couple more sets if anyone is interested.

Well, that’s my story for now. If anyone is near Cincinnati (actually Florence, KY) or Elkton, Ky, let me know. I build my parts in Florence and assemble in Elkton. It would be great to have some other builders close to discuss building, etc.

Bill Johnson – #023 – Florence, KY

Hi Bob, So glad to hear that you are ready (perhaps already have) to fly #2. Our second wing is going together quickly. Should have both sides, including control surfaces before the end of the year. Looking forward to starting on the fuselage.

The photo is my left wing with control surfaces installed. I am starting to look for a wind damaged Maule or C180/182 to scavenge for the engine and other needed parts. Still having a ball with the whole project.

Pat Fagan – #232 – Pearblossom, CA

Also from the Internet -I have most of the systems hooked up or at least roughed in. All the flight controls are working. I am finishing up the fuel system now. #75 is being powered by a (1996) Ford Taurus 3.0 24 valve engine that I modified with a polybelt GT. The engine has run with no propeller but hasn’t been run to RPM or load yet. Items needing to be finished are the fuel system, engine control linkages, a few things left on the cowl, and trimming everything. I am installing a removable interior for complete inspections in the future. I know that a lot of little details need to be worked out yet.

I am in the process of moving again. This time I am going to build a house and hanger at an air park. I hope to continue working on the Bear hawk through out the house project and get it in the air by at least late summer. How is everyone else doing on progress?

I will be happy to answer any questions the group has and give my opinion of what I may have done different. I will say as far as the plans I have followed them to the line and had very good results, The project gets more interesting when you start to improvise beyond the main part of the plane, i.e. engine controls and all the other goodies. Enough for now. Happy building.

Tom Yeoman – #075 – Apache Junction, AZ

Hi, Bob,
Things are moving along, not on schedule, but forward.

I was saddened to hear of Ray Thurston’s passing – It was like hearing about a family member.

The enclosed picture shows the flanging tool I used for the rib “holes” – it was made from a standard flycutter and worked great! The wood handle was used to exert pressure on the bearing. Steel washers were glued to the form bloc to serve as bearings for the center pin. This might be helpful to other builders so I am passing it along. All the Best,

Walt Draxler – #082 – Arlington Heights, IL

Bob, I hope this letter finds you and Mike in good health and fun flying in your Bearhawks. Enclosed is a check for my newsletter renewal – I have been so busy that I forgot to send it in. I’ve finally got a good start on my Bearhawk. I have all my small steel parts cut out. I am just finishing all my ribs and I am about to start on the wing spars. My goal is to have the wings done by the beginning of winter. I am enclosing some long overdue pictures of my project. I will be looking forward to seeing you and Mike at EAA again this year. If you need a place to stay for a couple of nights you can stay at my place. I am about 40 miles from Oshkosh. Maybe that is too far, let me know. I sure would like to hear your comments about my project. I can take criticism. I hope to have the wings framed up by then. I have a question about the fuel tanks. I noticed in one of the newsletters that you weld and rivet them. Is the riveting necessary? Can I just weld them? Is the riveting for added strength or just to hold them together for welding?

Ray Gabriel – # 334 – Greenleaf, WI

Ray, thanks for the nice letter and your newsletter renewal. Your parts look very good in the photos that you sent. Mike and I might be able to stay over at your place for one night while at Oshkosh, check with us at Oshkosh. It would be interesting to look over your project. The rivets in the fuel tanks are only to hold the sheets in place for welding. ~ Bob.

Ray Gabriel using a Liebert Hole Cutting Machine. Ray reports that a user can cut all the holes in all the ribs in about 3 hours with this machine. Also pictured are all the 4130 steel and a few of the aluminum parts ready for bending and drilling.



Bob, I have been meaning to write for sometime to thank you for the information in your newsletter. I have been working on my seating arrangement. The front seats incorporate a “captain’s table” arrangement for the mounting. Adjustments are made by pulling a side lever to the right and sliding the seats back and forth. The back of the front seats fold forward to allow entry to the rear passenger area. The back of the rear seat is adjustable. I used 3/4″ x .035 square tubing for the windows and door frames. I know that it costs a little more but it sure is easy to work with. I’ve got to relocate the rear window frame 2″ higher.

The engine is a Lycoming 0-540 of 235 HP. It will be pulling a fixed pitch McCauley 8452 Prop. I hope to have it up and running by October 2000.

George Anderson – #153 – Daphne, AL

Hello Bob, Just got the Jan 2000 Bear-Tracks. I am always looking forward to receiving the next issue. Sorry that we didn’t make it to the fly-in in Oct. We were planning on coming down to the fly-in and visit relatives but I came down with the flu – so maybe next time.

Thanks for the information in the newsletter – It must be nice to have two Bearhawks!

Thank you for coming to our cook-out last summer and I hope you can make it to our next one sometime in June this year. Since the cook-out there have been 4 of my neighbors talking about building Bearhawks. My daughter and son-in-law are planning on building one as soon as they finish their Cessna 140. We might have to change the name of the airport from Hale’s Landing to Bearhawk Landing!

I have been busy working on the 1959 Cessna 172 that I am restoring – it’s almost done. The Koala 202 is almost ready to cover and I have most of the 4130 steel hardware for my Bearhawk wings made. I have too many projects and not enough time or money to finish them all.

Do you have plans for any future modifications for the Bearhawk? If so what? How about plans in the newsletter for seat frames and tracks. I have found that the Tri-Pacer seats are hard to find.

Dan Riffee – #267 – Hale’s Landing, WV

Dan, Sorry to hear that you were sick and couldn’t make it to the fly-in. Like you say maybe next year. Mike and I really enjoyed our trip to Hale’s Landing last year and are looking forward to it again this year. When you firm up a date – let us know.

Currently I have no more modifications to the Bearhawk design planned. Your idea for seat drawings is a good one and I will work on that for a future newsletter. -Bob


Bob, Enclosed is a check for the 2000 newsletter, also I have a few questions:

1) The part of the nose ribs that form the leading edge, have you noticed on the prototype or do you forsee a problem with fretting because the metal is not secured together at the leading edge tip?

2) On the plans it calls out a 1.25″ flange on the main spar and a 1″ on the rear. The newsletter has instructions for laying out spar blanks : Width = web finished height PLUS 2 x flange width PLUS 1/16″. This will give a larger flange than calls out in the plans, the same also with the 9/16″ and 1/2″ marker for the rib flanges. I wonder if it makes a difference or would I have clearance problems later?

3) Are the spar webs square on both ends or do the root ends have the shape of the wing attach fittings to fill the gap between the fittings?

I have started slowly on the wings, having trouble getting consistently sized ribs but getting there, I have all my tools and shop set up so far and having a lot of fun.

Mark Skiba – #349 – Camarillo, CA

Mark, Looks like you are really getting into the drawings and giving them a good going over. As for your questions: 1) Fretting has not shown to be a problem on the prototype and I don’t see any indication that it would start. 2) Slightly larger or smaller flanges will not cause a problem. 3) The spar blanks have the shape of the wing attach fittings.

Your ribs should be consistent within about 1/32″, let me know if you are still having trouble with the ribs. Maybe I can give you some more pointers for rib construction. ~ Bob

Mike and I received notice that Ray Thurston’s #005 BEARHAWK project has been purchased from his estate by John H. Dugdale. Ray had completed a tremendous amount of work on his BEARHAWK and it would have been a shame to see it go to waste.

Hi Bob,

I’m making good progress on the BEARHAWK. I’m on the wheels and rudder hook up to the pedals (I had to move the rudder pedals back from the firewall for brake cylinder clearance). I have a 0-470 and Prop and a good lead for the mount.

The seats are installed and I’m rigging up the rest of the tail. I have included a few photos of me forming the T25 ribs 1/8″ bend with a steel mandrel on the anvil.

Do you have a date for the fall BEARHAWK Cookout?

Will Graft – #365 – Wadsworth, OH

Wil, good to hear from you. I mention the distance used on my rudder pedal setback on page 5 of this issue. As for the cook out – we are still working out the best date as October has suddenly become very busy. We will have a firm date by Sept 1. ~Bob


The following post is from the BEARHAWK e-group.

Today I had to go see the IA who helped my brother restore his Citabria and I mentioned the e-mail list discussion of reverse engineering a set of EDO floats. The one hassle which he could see, would be forming the “hoop” stiffeners which give the rounded top of the floats their shape. He showed me an old partially torn up EDO and it looked like they were formed in a brake and then formed into their rounded shape, similar to how the fuel bay wing skin stiffeners are made for the BEARHAWK wings, only with a LOT more curve. So it would be a lot of trial and error compensating for springback, and it would have to be redone for each size hoop due to the taper of the floats. Not an insurmountable challenge, but probably easier to copy a float with flat top and sides.

He did mention that in the EDO line the model 2425 is not rounded like the others, and might make a good candidate for duplication. If the model number is also the displacement, that might be a bit on the small side, but may be close enough if you don’t increase the gross weight above what is specified for the landplane version.

Other than the hoops the rest of the float looked pretty straightforward and ought to be easy to copy if you could get the right extrusions. The one thing I noticed was LOTS and LOTS of closely spaced rivets. I think I would prefer to build my floats in fiberglass if a set of suitable plans become available. Matter of fact, my friend the IA asked “why don’t you just design your own?”

Del Rawlings – #316 – Cordova, AK

Bob,

#232 is really coming along well now. I bent the top frame as you suggested and was pleased to find everything lined up! I almost have the entire frame tacked together.

I was wondering, do you call for any special bolts, like close tolerance or high strength in the wing struts or landing gear?

I am planning on an 0-540 for a powerplant, will any 0-540 core serve for setting up my motor mount or do I need the actual engine?

Pat Fagan – #232 – Pearblossom, CA

Pat, good to hear that the process worked, as for the special bolts question, the answer is no. The airplane was designed to use standard AN hardware. The actual engine would be best – short of that, make sure that the engine that you use is set up the same as your core and that it has the same mounting bosses that match your motor mount ~ Bob

Another note from the e-Group:

Has anyone perfected the “Barrows Method” of flanging the @#$% lightening holes?

Mike’s book as well as “BearTracks” makes this look real simple.

“Barrows” Method:

1. Wax it up.

2. Using the flange tool, lift the hole 30 degrees by smoothly going around it about 2-3 times.

3. Flip the rib over and push it down with the back of your flanging tool to lock in the 30 degrees and tame any bends.

4. Sit back, admire your work, and realize that you’re God’s Gift to the Bearhawk community and builders world over.

“Romanko” method:

1. Wax it up. (Even I couldn’t screw up this step)

2. Fail at smoothly taking the flanging tool around the @#$% hole. Instead, use the flanging tool like a soda pop opener and go around the @#$% hole lifting it up in increments equal to the width of the flanging tool.

3. Admire all waves you just put in the @#$% hole.

4. Wax it again, and go around the @#$% hole with the flanging tool, realizing the waves will never come out.

5. Flip the rib over and push the waves with the back of the flanging tool until you realize you really are having a hard time judging 30 degrees with your eye at 0400 in the morning. Induce more waves.

6. Sit back in amazement as you realize what was once a straight rib has turned into an oil can. Go outside. Look up. If you see stars, leave for the airport and get in some quick flying before work.

I know that some of you have built elaborate dies for forming your holes, but I really hate the thought of spending time doing that. Frankly, I’d prefer to keep everything “Barrows Simple”. I keep looking at Bob Barrows as my example. If he built THREE sets of wings using this method, it’s good enough for me. I think it’s just an issue of practice, but I really thought I’d have it down by now. Until I do, I will continue to refer to them as the @#$% lightening holes.

Bob Romanko – #399-Charlottesville, VA

Bob, Bob and I have agreed to conduct a personal workshop with you to perfect the “Barrows Method” of rib flanging. I got it on my first try. ~Mike

I found some rod ends at Sun & Fun for $12.00 each. Talked to the surplus dealer (Russell). He has about 1000 more of these jewels. The part number on the rod end is RE4H6-2 made by Fafnir (look at the Spruce catalog and you will see these are the right ones). If you would like to purchase, fax an order to Russell AT2 Surplus (847-432-6847). He said it takes time for him to fill orders so be patient.

Bill Johnson – #023 – Florence. KY

Bill, you look good sitting in that fuselage. I was able to confirm the rod end information with Russell – Order what you need builders! ~Mike

Bob, I’m enclosing some photos of my Bearhawk. I have completed the fuselage, both wings, wing-tips, fuel tanks (installed), nose bowl, and the seats. All cables are hooked up and operational.

I constructed the seats myself with 4130 tubing and
zig-zag springs for the seat bottoms and backs. They are fully adjustable front and back with a hinged back for access to the rear seat compartment.

I’m getting ready to mount my engine on the Bearhawk.
It is a Continental 0-470. I hope to have my Bearhawk in the air by next fall – God willing.

Things seem to be going very well building from your plans. I cut my first tube three years ago.

Sorry I missed seeing you and the prototype in May when I was on the east coast. Maybe it will work out better on my next visit. God Speed,

Boyd Newgen – 264 – Ontario, OR

Boyd, What a great letter to receive the day I return from Oshkosh! Thanks for all the great photos and keep them coming. I am glad to hear that you are making such good progress, ~Mike

Hi Bob & Mike, I have had the Bearhawk plans 5 years and I am only now just starting. I have done a Kitfox and a Thorp T-18 (which took People’s Choice at Oshkosh) in the early 80’s. I want my Bearhawk to do the same.

You mentioned that you stayed at Blackhawk Field in WI during your trip to Alaska. I hangared there for two years prior to coming to Oregon.

I am a steadfast promoter of the Bearhawk. Why someone didn’t think of it the 30 years proceeding Bob remains one of life’s mysteries!

Don Schindler – 068 – Springfield, OR

Dear Bob, Please send me a copy of the Utility Door Plans ($25 M.O. enclosed).

I have been studying the plans at great length, trying to create and assemble the aircraft in my mind. In this way I feel I will have an understanding of the aircraft as a complete idea and not just some parts to make and slap together. This activity alone has been a source of great entertainment for me.

I expect to be full bore into parts construction by the end of December.

I have a couple of questions for you concerning the plans – At the root end of the spars you show the .032 web is to be continued all the way under the spar end plates and the spar end inside plates. Also you show the web flange ending at the top and bottom of the spar slightly short of the corner angle of the end plates. this creates and inside right angle cut at the top and the bottom of the web material at the end of the flanges. Is this inside right angle cut a possible source of future web cracking from stress? Should I radius it or continue it as a gentle curve up to the flange?

Do the line diagrams of the fuselage tubing depict the inside, centerline, or outside of the tubes?

And finally are there any unusual cluster arrangements in the fuselage tubing joints?

Bion T. Rodgers – 436 – Mount Royal, NJ

Bion, You should have your utility door drawings by now – let me know what you think. As for your questions: You make a good point about the spar flange. There should be no sharp inside corners on ANY aircraft metal part. Use a 1/8″ radius or larger. The fuselage line drawings depict the CENTERLINE of each tube. And there are no unusual cluster joints used in the Bearhawk frame as designed. ~ Bob

Dear Bob, I was pleased to have made your acquaintance on the telephone the other day. As indicated I have purchased Ray Thurston’s Bearhawk project but have not yet collected it from Blenheim. I will collect it soon, in the meantime Mrs. Thurston has sent me the plans and I am studying these.

Ray has done a lot of work on his project and it is a tragedy that he was not able to complete it. I hope to be able to pick up where he left off and continue the quality of workmanship. I am not a trained engineer, but enjoy a challenge and have always had a “hands on” practical tendency to make and fix things – boats, engines, travelling irrigators amongst others.

We live on a small block (14 acres) about 14 miles from Christchurch. While we are within the Christchurch International Airport Control Zone, there is a possibility we could fly off the block (it is 515 meters long (that’s 1690 feet to you and me)). The big thing will be to not annoy the neighbors as the area is in the process of being divided into smaller and smaller blocks with people moving here from the city.

So far as the Bearhawk is concerned, I have not decided what engine to use yet. Personally I am not keen on air cooled engines, but there is considerably less work and less uncertainty involved in sticking with the Lycoming. I am also not keen on reduction drives as many of these seem to have some problems. I quite like the idea of an inverted, direct drive, alloy V8, such as Steve Whitman used in his Tailwind. No doubt this would take some development too. A Rover 3500cc can be stoked and resleaved to give over 5000cc and this would give enough HP, but this too would take some development.

I would appreciate if you could provide me with a bit more specific performance data re: the Bearhawk than is contained on the websites. If this has been published in the newsletters do not bother to repeat it (I am awaiting receipt of the back issues from Mrs. Thurston). I am interested in the specific performance of the prototypes – e.g. estimated HP of the engines and the cruise speed at 2400 RPM for each, climb rate, fuel burn at cruse. Do your take off and landing figures represent literally lifting off the ground or are they the traditional 50 foot obstacle clearance? Also can you supply some data on the Bearhawk’s ability to handle cross winds. I look forward to meeting you someday in the U.S. or in New Zealand

John Dugdale – 005 – Canterbury, NEW ZEALAND

John, Thank you for the introduction and I hope that you find the Bearhawk to be to your satisfaction once you begin construction. I considered Ray to be a very good friend even though he was on the other side of the planet and I am pleased to learn that all his hard work will not go to waste. I think that you will find the answers to most of your questions in the back issues of the newsletters. My performance figures represent actually lifting off the ground. I personally think that the Bearhawk handles crosswinds quite well. The nearest production airplanes that would be close in crosswind competence would be the Husky, Super Cub or Citabria. ~Bob

1997 Beartracks Mailbag, Q&A with Bob

Source: 1997 Beartracks, Bob Barrows

The mailbag has been stuffed the last few months. A lot of good progress has been made by several builders who want to pass along information. A lot of questions about different powerplants are being raised about everything from Fords to Chevys to turbines and everything in between.

Bob,

I’ve been thinking of using a Turbo-Prop engine in my BEARHAWK. Turbomach T62 t401c1 (Solar) of 225 SHP available new surplus @$4750. However I need to find a matching gear reduction unit (PRSU) for approximately 2.5 or 3 to 1 reduction and constant speed prop unit. I haven’t been able to work out the details yet but I will make engine and cost comparisons this winter and work on the installation problems too.

I am somewhat familiar with turbine engine conversions as I assisted in a COX TURBINE OTTER conversion in Seattle, WA and have 30 years experience as an aeronautical engineer with Boeing.

My hope is that a turbine combination will result in lowest empty weight for maximum performance at similar cost compared to the Franklin 220 and Lycoming choices.

Paul Hubble – #126 – Deer Park, WA

A letter off the net –

I finished building a Murphy rebel in April of this year. I now have 60 hours on it and it flies real nice. Out here in the west (Barstow, CA) density altitude is a problem. I decided to build the BEARHAWK to get a little more room and also a larger engine. Right now I am leaning toward an auto conversion by Belted Air Power, of Las Vegas. They use brand new Chevy V6 engines and sell a complete firewall forward package for the RV-6 for $8000. We looked at it at Copperstate and liked it. It puts out 225 hp and uses a belt drive reduction. Bob Barrows was right in one of the newsletters when he said not to worry about the engine until it is necessary. I learned that from the Rebel, I rushed into buying a Lycoming O-235 and now everyone is using O-320’s.

I have started building ailerons and flaps. I got to the point where I needed
spars. There has been some concern lately about purchasing spars and I thought you all might like to know what I did. We have a heating/sheet metal shop in town. I took two sets of .032 blanks to the shop with the spar drawings and described what I needed. I now have four spars and the trailing edges all for $80 in labor. They did a nice job but I had to educate them in using 2024-T3. No sharp bends or scratches. I had them look at the information in the newsletter on bending the spar webs and trailing edges. I think it would be worth looking in to for other builders.

Rich Bartman- #18 – Newberry Springs, CA

Bob,

Could you give me the phone number and address for the manufacturer/supplier of the square section coiled springs for the undercarriage.

Also included are a few photos taken a little while ago. I am now preparing to skin the starboard wing.

Ray Thurston – New Zealand

Ray,

Thanks for the letter and the photographs of your wing and fuel tanks. They both look real good.

The springs for the landing gear are made by three different U.S. companies that I know of. Dayton, Dieco, and Danly. Use the Dayton spring if you can, the part number is EH 200-800.

Dayton Progress Corp – 500 Progress Rd – Dayton, 0H 45449-0039 – USA Ph-513/859-5111.

The springs should be about $40 each.

All builders are invited to send in photos of your progress for publication in Bear-Tracks. – Bob.

Bob,

Enclosed please find a check for another year of Bear-Tracks. I show one more issue left on my current subscription. I have begun construction on my BEARHAWK and I have a few questions I am hoping you could address. How critical are minor scratches in aluminum parts? Is there a way to fix this? Do you recommend priming all parts before assembly? What is the best way to measure rivet spacing on ribs (for fluting purposes). And one last question, what method is recommended for cutting aluminum plate? Thanks for a great design and all of your help.

Kirk Urbanczy – #166 – Palm Springs, CA

Kirk,

Thank you for your newsletter renewal, please note that subscriptions for the newsletter run from year to year, not the date of purchase of the plans. Regarding your questions:

Keep the aluminum as scratch free as you can. Scratches you can feel with your fingernail should be sanded with 400 grit sandpaper till smooth. Priming all aluminum parts separate is best but you need only to prime the spar pieces before riveting together. Measure rivet spacing according to information on the drawings and flute half way between each rivet. Once one rib is done it can be used as a template for the others. Cut aluminum plate .062 and thicker by sawing or shearing, .050 and thinner can be cut with large duck bill tin snips.

Bob

Bob,

I like your advice on things like cargo doors and more fuel tanks, I will opt to do none of them. I am plans #198 and have all of my ribs just about finished. Thanks for a great set of plans.

Larry Mader – #198- Spearfish, SD

Bob,

Don’t feel bad about not providing a materials list. John Thorp didn’t provide one for the T-18 and he finally told the builders that all of his time was spent on designing, drawings, etc. and it was something he couldn’t get to. So you see – life repeats itself right?

I have to build a house before I start my BEARHAWK but I will do a list if someone doesn’t do it first.

Here’s a tip from the book The All Metal Airplane perhaps you might want to pass it along to the builders. “When working on sheets of aluminum
staple corrugated cardboard to the surface of your bench. The little aluminum particles will fall into the corrugations and will not scratch your sheets. ”

Donald Schindler A&P – #68- Madison, WI

Bob,

Last week I sold my French wood project Yodel DR315. I had to work really hard to sell it so I have not done much on my BEARHAWK. I am trying to sort out some paperwork before I pay and ask Swedish EAA chapter about the building licence. I have to ask you some questions:

1- What about the formblocks for ribs that go inside the spar (see drawing) should I take away a little bit on formblock?

2- For welding in Sweden EAA chapter 222 we have to test for it, then we get a license for 6 months. I have spoke to one boy who has got a license and it looks not easy, even if you have got experience. Do you know anything about the ready build frames for the BEARHAWK? Quality on welds, price and so on?

Thanks for interesting Newsletters and hang on with God Speed and Quality Bob!

Sune Larsson – #172 – Gislaved, SWEDEN

Sune,

Thank you for your letter, regarding your questions,

The rib shape at the spar interface does require some modification to your formblock. I have put a jog in the rib flange as shown in the drawings by slightly undercutting the formblock as you stated.

I am currently building up another set of wings to see if the wing skins will fit up well without the jog. So far everything looks good. Look for more information in upcoming newsletters.

It is best that you weld your airframe together, as the U.S.A. suppliers are not set up yet. A&E is no longer offering BEARHAWK parts as he is trying to get out of the business. One option you might explore is to tack weld your fuselage together and pay someone, skilled in aircraft welding, to come in and weld it up for you. If you have the airplane tack welded together it should take no more than 30 – 40 hours for a skilled welder to do it for you. Check with your EAA chapter to see if this is legal in your country.

Bob

Bob,

First of all belated “Happy New Year” to you and yours. I hope yours was a most blessed Christmas. Ours was! Among other things, we were blessed with over 8 feet of snow! You have probably heard of the roofs caving in from lack of shovelling.

Said shovelling is what has occupied most of my fall and winter. Aside from a terminally short memory, it is my only excuse for not having renewed my subscription. Enclosed herewith is the required U.S. funds along with a request to bring me up to date.

Progress with this project has only been fair. I have all the rigs made, stiffened, primed with angles riveted in place. A tip for others is offered: Selecting appropriately sized short ends of pipe and bevelling in a lathe made the punch to press the edges of lighting holes into the matching recesses cut into the wood rib former resulting in a very smooth, stiffened rib. I cut the recess in the rib form with the same circle cutter in the drill press but used a specially sharpened tool bit. Keeping everything concentric was easy using the same sized 3/16″ jig pin hole into which torx drive screwdrivers (for one thing) fit perfectly for alignment! For pressing, I used a Dake arbor press with a clamped down work piece. The rings used to clamp the rib flat around the outside of the circle were large ball bearing races that are fairly common.

I encountered considerable disappointment with my first spar. I am now awaiting new material to build another (as I unwittingly only ordered half enough the first time). For a first time builder I could have used a lot more tips to avoid a lot of mistakes. I found that the cap strips moved considerably as I progressively riveted them on. The result was a lot of clean-up drilling of holes and too many epitrochoidal shaped holes reminiscent of a rotary Wankel engine! The killer was a preacher friend who lives some 90 miles away but who has experience building an RV-6. His critique was devastating and I nearly gave up. Fortunately I have some very loving and supportive family members who encouraged me onward. One was a sweet 20 year old step-daughter (Miss Creston 1993) who said “Don’t give up, I want to fly that thing when you’ve got it done.” Hey, how could I quit, eh?

I have all the steel I need and lots to do, but other loved ones need attention too. One in his rush to meet the growing demand for gas-heat and another who decided to build a new house in August. He is moving in this weekend. So it has been a busy but blessed time. My friend in Arizona calls every now and again to tell me how nice it is down there. I think he still has his Stearman and is nearly finished with his MonoCoach fuselage that I worked on with him last winter down there. He is still contemplating a BEARHAWK but can’t seem to justify a fifth aircraft to his wife. I told him to be more assertive. She about threw me out!

With the snow having caved in a local hanger on a 182, 1 just might have a line on a engine, some avionics and some other parts. We are dickering! Have a Great year!

Rod Dressel – #190 Creston,BC, Canada

Rod,

Thanks for the interesting update on your project. I hope the construction of the BEARHAWK is going more smoothly for you now. You are lucky to have such a supportive family during your building process.

I just built another set of spars and do not remember any problems with the holes, but I decided to revisit that in this issue of BEAR-TRACKS in case any other builders are having problems.

Our banks charge $12 to cash a foreign bank check even if it is in US funds like you sent. Please send an international money order or cash in the future.

BOB

Bob,

Moving right along beating out ribs on #164. 1 have a few questions that I could not find the answer to after studying the drawings.


  • What is the thickness of the material for ribs 3 and 4 (the short ones behind the fuel tank)? .032

  • What is the thickness of the material for the flap ribs? .025

  • What is the thickness of the material for the aileron ribs? .025

Thanks,

Russ Erb – #164 – Edwards, CA

Russ,

Sorry that info was not on the plans. I have now added that information to the plans. Thanks for your questions.

BOB

Bob,

I have just been doing a cable run check in the wings prior to putting them to one side to start on the fuselage.

I had previously checked the aileron cables before skinning but I did not have the flaps in place at that stage. Now I find that the flap push rod in about mid-position just makes contact with the cable in this area.

1) Could a fairlead be positioned in this area to give, say, 1/4″ cable clearance with the push rod? The cable should not be more than 2° – 3° from straight.

2) One other thing is the flap actuating lever attached to the 3/4″ torque tube at rib #1, 1 have positioned this lever as per your drawing N. 14, it would seem that the aileron cable passing through the fairlead at rib #1 may touch the end of this arm.

Would you please advise me on these points so that I may proceed with the project.

Regards,

Ray Thurston #005 – NEW ZEALAND

Ray,

I hope the wing building process went well for you, I think you will really enjoy building the fuselage as you will have something that will look like an airplane soon!

Regarding your questions, 1) The aileron cable touching the flap push rod is not serious, the fairlead in this area would be a good idea though, I have noticed this same situation in the prototype. I am considering installation of a plastic sleeve on either the push rod or along 8″ of the cable to stop a metal to metal rub on the prototype.

2) The actuating arm at the end of the torque tube may be shortened enough to eliminate any interference with the aileron cable.

Good Luck – Bob

Tom Yeomans #75 – Richland MI gave us a call at the shop to order the new strut material and report that he has his wings just about done and his basic fuselage welded up ready for its gear.

Hello Bob,

Hope this finds you and your family well!

S/N 52 and 53 going together slow but sure. We will be skinning wings in a few weeks.

Sorry, but I let my Bear-Tracks lapse – my last issue was October 1996. Could you please start me up at the next one after that? Thanks! Please send me a set of the Disogrin Rings. Check enclosed to cover the newsletter and rings.

I have a few questions :

1) Where do you pick up your static pressure for instruments?

2) Is the bottom skin (tip to #5 rib) .025 or .032? It is not on the plans but I had a bug that it was .032?

3) From the newsletter illustrating skinning was not clear as to which way the step on the bottom of the front spar goes, bottom skin on top or vice versa?

4) Do you know of any adverse characteristics of using A-10 warthog style wing tips?

Thanks, Be Well,

Douglas Jasper #53 – Corona, Ca.

Douglas,

Your newsletters to date and Disogrin rings are on their way. In answer to your questions,

1) I did not run a separate static line to the outside, take a look at production aircraft similar to the BEARHAWK (Maule, Cessna 180, Super Cub) to get an idea as to where to place one. You may also check out Tony’s books for more information on this subject.

2) The skin you mention is. 025 thick in that area.

3) You can attach the skin either way but the best sequence is as I have illustrated (in sketch #2 note the riveting sequence for ease of bucking rivets):

4)That style of wingtip should be OK – keep it light!

Good Luck – Bob

Bob, I have a few questions you may be able to answer before you head for Oshkosh:

1) Stringers; Your drawings show 1″ x 1/4″ x .032. All I can find here at present is 5/8″ x 5/16″ x .032. Would they be strong enough?

2) Are there any pulleys or fairleads required in the trim cable system?

3) How do you access the trim shaft bearings in the tailplane for lubrication after the fabric is on?

4) Do you bother drilling the airframe tubing to flush linseed oil through after welding?

5) The rudder horn for the tailwheel chain/SPring have no details given, just match up with the horn on the tailwheel?

6) The streamline tube strut stabilizer to fuselage, how do you provide for adjustment if the angle of incidence requires altering?

Regards – Ray Thurston #005 – NEW ZEALAND

Ray,

I am starting to get a lot of questions about the fuselage now. I assume lot of the builders are done with their wings and tail feathers and are starting on the fuselages. Regarding your questions

1) The stringer material that you spec out is OK as long as you use extra stand offs as needed. 1 x 1/4″ wood is OK also.

2) I am using two fair leads on fuselage center-line top at station M and station J.

3) No access on the prototype, shafts and bushings. I epoxy painted and greased on assembly. No problems to date.

4) No. Keep tubes welded airtight or protect inside of tubes. You may drill as you described if you want.

5) Builders choice to match with tail wheel used.

6) Rework end of streamline tubing as needed for fit.

Thanks for your questions and keep in touch. ~Bob

Hi Bob, Construction has started on #238. The newsletters are a priceless complement to the drawings. I’m starting as recommended with the wings. I have some questions maybe you could help me with, so that when I get to these points, I don’t have to sit around and ponder.

1) I have access to some 2024T3 .040. I was thinking of using this for the main spar web. I tried bending some test pieces in a brake and found that a 3/8″ radius provides a very nice bend. I realize it will make the spar slightly heavier but, maybe a bit stronger. Eventually I plan to put my BEARHAWK on floats. Having flown hundreds of hours on floats I know what kind of punishment an airframe can be subjected to! Would .040 2024T3 be acceptable for the main spar web?

2) From what I can see in the plans and the newsletters, the lightening holes in the spar web do not have flanges, is this correct?

3) Spar strips (cap strips) in the plans call for 1/8″ 2024T3. I can get 1/8″ x 1 1/2″angle 2024T351 to cut up. “T3” is heat treated and then cold worked. I am uncertain what the “51” stands for. Is this material OK?

Having studied the blueprints closely I find there should be very little to stumble on. You’ve done a very nice job. This is going to be a fun project!!

Dave Hiebert #238 – Alberta, CANADA

Dave,

Thank you for you kind comments about the plans. I think you will really enjoy building the BEARHAWK. Regarding your questions

1) .040 for the spar web will work fine but a minimum .140 bend radius is required in order to not stress the material to cracking.

2) Yes – no flanges are required.

3) The 2024T351 will work fine in this area. “T351” = solution heat treated, stress relieved, stretched, cold worked. Where is your supplier and what is the cost? Other builders may be interested in your area. Good luck and keep us updated as to your progress! ~ Bob

Mr. Barrows,

I want to thank you for your hospitality and the time that you took to show me “The BEARHAWK”. Having the opportunity to see the aircraft both finished and under construction was a great help. Being able to see the straight forward approach to fabrication of detail parts and the uncomplicated assembly set me at ease that everything was indeed as advertised and well thought out.

I have begun to to fabricate all the form blocks for the wing components and have found the plans to be very clear and accurate. On the few occasions that something seemed out of place all I had to do was study the plans a little closer to find out why and then correct the error in my ways. I have helped others with “Kit Aircraft” and found the plans not accurate or clear.

Again, my thanks.

I will want the wing struts when available. Updates to follow as I progress.

Kevin Deutscher #272 – Phoenix, AZ

Bob,

Thank you for letting my wife and I come down and look at the BEARHAWK. I learned quite a bit and realized that it is even more of the aircraft that I want, than I thought it was by looking at the plans. Now I just need to get busy and finish the house so I can start on it. I have a 48′ x 60′ hanger beside my house and I need to get it insulated before winter so I can work on my BEARHAWK full time this winter.

If you know anyone that would be interested in my 1956 Cessna 172, give them my phone number – it will help finance my BEARHAWK.

I am really looking forward to the next issue of the newsletter – which I think is excellent.

Dan Riffee #267 – Elizabeth, WV 304/275-0976

Bob,

While visiting you a month or so ago you showed me a device that you used to insure correct alignment of the nose ribs. Could you send me a sketch of that device? That method seems a lot easier than the running a wire through the ribs. I also have some questions.

1) On drawing #14 no attachment method is shown for connecting the 1/8″ flap cable to the inboard flap lever. Could you suggest a suitable method?

2) When connecting the 1/8″ cables to the bellcranks (drawing #11) is a clevis pin through the shackle and turnbuckle OK or should a bolt be used?

3) Also could you confirm that in drawing #14 that the flap lever is shown in the position full up flaps?

Thank you

Tim Neal #209 – Uniontown, PA

Tim,

Below is a sketch of the device that I used on the latest set of BEARHAWK wings that I am building.

Regarding your questions,

1) Use a cable shackle

2) Clevis pin or bolt is OK.

3) The drawing shows the flaps in the full up position.

Keep in touch. ~Bob

Builder Update

Below is a photo of #075 – Tom Yeomans’ project. As you can see he has his wings done as well as most of his fuselage! Thanks for the photo Tom!

Making Fluting Pliers

Source: 1995 Beartracks, Bob Barrows



Fluting Pliers – You can buy a set of fluting pliers (very expensive) or you can make your own. To make your own you will need a set of Large Pliers. Clamp the pliers in a vise and drill a 1/4″ hole between the jaws. It may help to soften the pliers first with a torch. Then braze a section of 3/16″ rod on one side of the pliers. File as needed to produce a nice smooth radius around the rod and along the rim of the jaws.

Using your fluting pliers, flute rib at approximately 1-1/2″ spacing to straighten out the rib after tapping flange over to a 90° angle.

These homemade fluting pliers seem to work better than the units sold on the market. The homemade pliers make a smaller crimp that is much easier to work into the rivet pattern.

Bob’s Method for Making Wing Ribs

Source: 1995 Beartracks, Bob Barrows
Here are a few tips to help you build ribs. I would strongly recommend that you purchase all three (Note there are four Bingelis books now) of Tony Bingelis’ books to help you through the construction of your BEARHAWK. You can order his books from the EAA (or via this link). The EAA also offers VCR tapes and other books that you may find helpful during construction.

BOOKS BY TONY BINGELIS…


  • THE SPORTPLANE BUILDER
  • FIREWALL FORWARD
  • SPORTPLANE CONSTRUCTION TECHNIQUES
  • TONY BINGELIS ON ENGINES

MARKING TOOL – – –


One of the more useful tools I have is the marking tool guide. The guide is nothing more than a plastic circle of 1/4″ thick material with a 1/4″ hole in the center to fit a marker in. The tool rolls along the edge of the form block as you mark out the proper sized flange. You will need to make two of these guides, one for a 9/16″ flange and one for a 1/2″ flange.







After marking the rib remove it from the form block. Cut out rib blank with large Duck Bill tin snips. Polish all edges smooth.





Hold the above assembly in a large vice and ‘C’ clamp as needed to keep the two blocks together. Lightly tap down flange over rib form block being sure the radius is set. The flange will be wavy. Take your time and work your way around the rib.








After you are finished forming the flange, remove the rib from the form block and set it on a large flat surface. Using your mallet lightly tap the flange over to a 90° angle. Again, take your time and work around the rib.



Flanging Lightening Holes



After forming the rib it is time to cut in the lightening holes and flange them. Using a fly cutter and a drill press cut the proper sized holes in the ribs. You will now use the flanging tool to put a 30° finish angle on the lightening holes. Pull up on the tool and slide around hole 2 – 3 turns until approximately a 30° angle is formed. Wax aluminum as needed for smooth operation of the flanging tool. After forming flange the rib will be slightly warped. To correct this set the rib on two wood blocks with the flange pointing down. Using the butt end of the flanging tool apply pressure to the flange and slide it around to straighten out the rib.