Russ’s Home Made Straight Edges

Source: 2001 Beartracks, Russ Erb

At some point in your construction, probably after finishing your ribs and spars, you’ll need to start laying out a bunch of stuff. This involves drawing a whole mess of lines. Just like when you were in school, this will require copious use of a straightedge.

I got my most useful and favorite straightedge quite by accident. It started out life as a leftover strip of 0.025 aluminum from making blanks for the rib stiffener angles. Thus it is a little over 1 inch wide and about 3 feet long. It was cut on a 4 foot shear, so I know the edge is straight.

I have used other straightedges, of course. When I’ve needed something shorter, I’ve used the 6″ or 12″ rules from a couple of combination squares. For really long line I’ve used an (aluminum) 4 foot drywall square. On occasion I’ve also picked up a piece of fuel tank strap (1″ x .025 4130 steel).

So why is my favorite my favorite? Two reasons:

1. It’s flexible, so it will bend with the surface of the wing, such as drawing the centerlines of the ribs on the wing skin while the skin is on the ribs. The rules from the combination squares are stiff and won’t bend (more than once). The drywall square is too unwieldy and heavy for most jobs.

2. (The main reason) For reasons I can’t fully explain, any steel rules (or the steel straps) are hard to slide on the aluminum sheet to get in just the right position. My best guess is that the edges are trying to dig in to the aluminum, and the aluminum is just gummy enough to catch the edge. In contrast, the aluminum straightedge slides into position very easily. Much nicer.

I also took a similar piece of aluminum and bent it around the same pipe I used to form the leading edges. I use this one to draw lines around the sharp corners near the leading edge.

My recommendation to you is if you find access to a shear to cut the strips for your rib stiffening angles (check with local air conditioning contractors if all else fails), cut a few extra strips while you’re at it to use for drawing later. Costs next to nothing; has benefits in excess of many expensive tools.

Russ Erb – #164 – Edwards CA

Fixed Rudder Trim Tab

Source: 2001 Beartracks

I know that The Bob put a fixed trim tab
on the rudder of Proto I. What material and thickness did he use (aluminum or steel)? Was a rudder trim tab needed on Proto II? Are there any recommendations for changing the 3/4″ fin offset for the larger engines? Like Pat Fagan, I’m building a mount for the trim tab into my rudder, but I don’t intend to actually install the tab unless it proves necessary.

Russ Erb -#164 – Edwards CA

Russ – Bob used a piece of .032 2024 aluminum for the trim tab on the prototype. He installed the mounting tabs on Bearhawk 260 for the trim tab but found that the trim tab is not needed. He thinks that the 3/4″” offset is fine for most engines.

Bearhawk 2000 Fly-In

Source: 2001 Beartracks, Mike Meador

Just a short report to let you know how the October 28, 2000 Fly-In at Barrows Airfield went. The weather was nice – we could of used a little less wind but otherwise it went off with out a hitch! We had a new record of 6 fly-in aircraft (none of them Bearhawks) and 70+ attendees. This fly-in did boast the most plans owners in attendance at 15. 1 am not going to try to list all of them but they were from all over the country.

Bob and I would like to thank everyone that attended and we both hope that you had as good a time as we did! Looking forward to next year when there should be a couple of “New” Bearhawks in attendance.

2001 Builder Updates

Source: 2001 Beartracks

The photo to the right was sent in by Jack Piggott #374. He completed his wings in October and was astounded that they were straight and twist free! He thinks that it was a miracle but Bob and I think it was good old fashion hard work.

Hi Bob and Mike, Lots of adventures since the last writing, including radiation treatment, operations, travels, 75th birthday, installing two trail bridges in the Idaho back country, and at last, very near completion of both wings. Photo enclosed (see cover – M). The right wing comes out of the jig tonight, then final installation of (completed) fuel tanks. I am making the tank caps to your pattern, which avoids another hole in the wing.

Next week (or so) I will bend up .032 channels and start on the tail feathers. Hopefully, this will go a little faster since I am more familiar with the medium.

I have to apologize to those builders who have been trying to make contact with me by phone. My shop (friend’s shop, actually) is up the street and I don’t leave my machine on all the time. If any builders want to get in touch with me please leave a voice message before 9 am or after 6 p.m. I am having to get involved with an office in our local EAA Chapter 430 to pay back a little of the time and support from them. Paul Messinger, my Tech Counselor, has given generously of his time and advice for which I am truly grateful.

We are now looking for an 0-540 w/logs, preferably a mid-time take-out at a reasonable price. Failing that, I will go for a run-out which I will overhaul under IA supervision.

During a 10 day visit to Alaska, I got in 2 hours 172 time and 2 hours in a Citabria. I also collected some freebie parts: C-175 Struts, seats, gyro compass and an artificial horizon. Paul picked up a Bearhawk hat at Sun N Fun last year which I proudly wear to EAA meetings. Best regards to you both.

Jack Piggott – #347 – Sequim, WA

Jack, Great to hear from you and congratulations on finishing such a large component of the construction process. The photos were great keep them coming. Good luck on the engine search. – Mike

Below are a few photos by Bill Johnson of Bearhawk #023 getting its exhaust system fitted. Bill’s website has many photos of his project. His web address is: http://home.fuse.net/wjohnson/

Hi Guys

N156RM was inspected by the FAA on May 3 and flown the first time on May 4. After several take off and landings the BH out performs my 150hp Citabria, the controls are more responsive. This plane flys fantastic, it’s STOL all right. The only problem, a bad tailwheel, got to get rid of the Maule and replace it with either a Scott or a Bob Wheel. My first flight was over an hour, had to quit because of shortage of fuel on hand. Got to get my fuel barrel filled. Its hard to keep from flying it, FANTASTIC!

Bob Marek 019 – Cadott WI

CONGRATULATIONS Bob! Your Bearhawk is indeed the First to Fly! Bob and I are looking forward to seeing it in person soon! See page 7 for Bob’s Weight and Balance information and a short report about its construction and page 6 for more photos. Below are a few photos of Wil Grafts #365 – It should be in the air soon too!

Bob & Mike, Another year has passed and I’m still plugging away, I only get an hour and a half each evening and a few hours on the weekends to work on my project, but one piece at a time. All the wing ribs have been done for quite some time, everything for both wings is made except for the steel parts.

I did finally decide to remake the aileron and flap ribs because the lightning holes closest to the spars were too close to the angle aluminum stiffener. The angle would “ride up” on the lightning hole flange. Just a 1/4″ off but I decided to remake them. Both ailerons are now all clecoed together and are waiting for me to bend the trailing edges and form the nose skins. Everything is cut out and ready – I’m just waiting until I cross paths with the man that owns the 8′ brake. In the meantime I’ve gotten all the pieces for the flaps cut out and just have to clean them up. At this point I have just under 600 hours in the project. Slow but I’m happy. I read the online Bearhawk digest every morning, they are really helpful, some a little off the deep end, but a good bunch of guys. One of these years I’ll make it to your cook out. Fly Safe.

Sonny Cilley – #234 Royalton, VT

Sonny, thanks for the update, Bob and I like to hear back from builders about build times at various stages of construction. It is important to DO SOMETHING EVERYDAY with your project if you want to finish it, you sound like you have a good time program worked out.

Bob & Mike, Thanks for sending the 2000 back issues, and I’ve included a check for the ’01 subscription. Art Womack of Kenai, AK and I are working on our Bearhawk; some of it is in Alaska and some of it is here in Texas – all the parts will meet one day! Art’s mailing address is PO Box 7475, Nikiski, AK 99635. He is working on the fuselage and I on the wings.

Mike, are there any websites with some builders that I may visit?

Bob, Why did you choose the Lycoming 0-540 rather than the Continental 0-470? Parts? Cost?

Kevin Lammers – #059 Montgomery, TX

kklammers@aol.com

Kevin, Thanks for the renewal. That is quite a system to build a Bearhawk – just be sure that you both have matching tape measures! There are several builders websites – I’ve put your e-mail address up so that they can contact you directly. Bob picked the 0-540 because that is what we work with most. We have a good supply of parts and build 10 – 15 Lycomings a year. The 0-470 is an excellent engine for a Bearhawk and we hope to see one in flying this year in Wil Graft’s project. ~Mike

Bob & Mike, Progress on Serial Number 479 continues. All nose ribs and main ribs are complete. Work is now focused on the wing’s steel components. My father and I are enjoying the time together. We would like to thank you for sharing this wonderful project with the rest of the flying community.

Dennis (the son) & Stan (the dad) O’Connor #479 – Fort Collins, CO

Dan Montee #414 sent in the license plate below. Seems that he has been doing some extended taxiing in his “Bear Hwk.” Bob and I like the fact that it is a TRUCK plate.

A Few Builder Photos

A couple more photos of Bob Marek’s Bearhawk. He does not have a radio installed – just using a hand held right now.

It is a little difficult to make out in the photo but it looks like he installed toe brakes on the left side only.

Doesn’t look like he strayed very far from the drawings. He built his doors just like Bob did on the Prototype and the 260. He did add a hand hold near the rear horizontal stabilizer strut – A good idea.

The C.G. Information on page 7 shows that he flew his first flight at 20.6% right about where you want to be during the initial flight testing program. I’m sure that we will have more information and photos in the next newsletter – Mike


Above are a couple of photos of George Jensen’s Bearhawk #026. The fuselage is upside-down in the first photo. George has finished his wings and is moving right along on the fuselage.



Pictured to the right is a photo of Pat Fagan and the current status of #232.

Bob, I’m in the process of fabricating my aileron bellcrank. Could you explain the dimensions and installation of the bearing and needed spacer tube, etc. I have not been able to locate 3/4 X .083 tubing. Is .065 wall enough or should .095 wall be used?

Tim Anderson – #398 – Brooks AFB, TX

Tim, The spacer tube is to insure that the bearing is not crushed when the AN4 bolt is made tight. The .095 wall thickness tubing should be used. It is necessary to machine it down to the. 083 to fit the bearing. ~Bob

Hi fellow Bearhawkers,

Just to clear up the confusion #434 is a joint effort between Richard and myself and now that we have another one flying I am no longer inspired but down right jealous, congratulations.

As for the African Bearhawk I am a member of EAA 322 in Johannesburg South Africa and had advertised some aluminum plate for sale, when I was contacted by a young chap in a small mining town about 60 miles from me.

When I asked him what he needed the aluminum for I almost fell off my chair when he said to complete an instrument panel in his Bearhawk. Well, at this point I volunteered to deliver the aluminum to him, Richard and I went down to the town of Fochville in the Free state and low and behold here is a Bearhawk.


I took some pictures but as you can see space is a problem, the pictures were taken in Feb 2001 and the wings were also complete at that time, we have not made contact since but will make an effort to visit him again

Wayne Estment- #434 – South Hills, SOUTH AFRICA

The above photos are of Waa Van Zelm’s #368 in Fochville, South Africa. Thanks for the photos Wayne.


We received late word as this issue was going to press that Merv Hargraves #362 in Queensland, Australia has completed his Bearhawk. We hope to have some photos and information from Merv for the next issue of Bear-Tracks. Good work Merv! Below are a couple of photos from a few Bearhawk Kits being manufactured in Mexico. Visit www.bearhawkaircraft.com if you would like to see more.


From the e-Group:

Charlie Volgesong (Dillsburg 4130 Tubing supplier) really runs a tight ship. My tubing was delivered yesterday, a week after it was ordered. ABF motor freight brought it out and the driver helped me drag it 100 feet from the street to the garage.

There is about a days worth of work left before the second wing goes into storage, then on to the fuselage for a while. I used Bob’s method of Loctite 609 for aligning and securing the rod ends in the flap and aileron mounts. It really works well. With the first wing I was a little sloppy with the Loctite and found it will strip Stits Epoxy if runs are not promptly wiped up. I was careful to lightly coat the rod ends and insert them on the second wing and had no problems.

When I started on #303 1 decided against keeping a log of work hours. I have done so on every project before and reasoned this is just for fun. After seeing actual times and estimates I decided to keep a record on the second wing assembly. All jigs and tooling had been built during the assembly of the first wing. All parts except the skins were complete when the assembly and timekeeping started. This morning I am at 272 hours with 6 to 8 hours to complete and store.

Bill Cox – #303 – Baytown, TX

Thanks for the comments Bill – keep us updated as to your progress – Mike

Kevin’s Pitot Tips

Source: 2001 Beartracks

Kevin Deutscher offered up these comments about installing a pitot system in your Bearhawk:

The Art of Pitot Tubing does have a few constants that should be observed for best results. The items outlined here are framed with the Bearhawk in mind, applicability to other aircraft is by hit or miss.

1. Locate the pitot tube and the static port at the same wing mounted location.

2. Locate the mast at the leading edge outboard of the flap / aileron junction. (Flap extension does back air up under the wing increasing local pressures causing a change in airflow around the front of the wing.) Note: there will be an induced error when turning due to the different velocity of the wings. This is a bigger effect than you might think; however, mount in too close to the prop arc and that becomes interesting also.

3. The mast should extend as a minimum 18 inches in front of the wing LE. Underwing locations ala Cessna and Piper work poorly on a flat bottomed airfoil.

4. The static ports should be 4 holes ( start at about .040 Dia ) located radially to the mast. 90 deg spacing. Holes should have orientation with the 1st hole at the 45 deg position. Holes drilled into a common plenum. ( minimizes pitch and yaw effects ) Holes should be located in an annulus or behind a stepped cut of about .030 deep.

5. Tubing runs should be of good practice, large sweeps, slope to low point. no leaks, constant tubing size, no fitting restrictions.

6. The Pitot hole is magic, hole should be round, square to the airstream and have sharp edges ID and OD. Size does make a difference. Consult with the mfg. of your airspeed indicator, the speed range of the aircraft does affect to a small degree the hole size and system accuracy.

7. Lots of little things do add up.

All for now, back to the 110 temps.

Kevin Bearhawk- #272 – Phoenix, AZ

Thanks for the information Kevin, keep cool out there.

Wil Graff’s First Flight Report

Source: 2001 Beartracks
Another Bearhawk is in the air! Wil Graft’s #365 flew on July 6th. Below is a photo and a brief description of the process.

#365 is flying. FAA inspection and first flight was on July 6th. With the O-470 and a constant speed prop, it climbs like a rocket. I have to fly off another 22 hrs., plan on flying to OSHKOSH. There are gear and strut fairings to finish. I’m still on cloud nine. Lots of questions and not much time to answer. I’ll list a few of the specs this time and try to cover more next time. I used a C/182 O-470-R engine and mount (not from my 182, it was sold and now in AK). The mount was cut down to fit and reinforced at the main tube clusters. The engine is under 500 lbs. Wt of ship 1392 with battery 15 in. aft of baggage bulkhead. No electric hookup or starter yet. Exhaust system made by Aircraft Exhaust in Jumping Branch, WV. Here’s one photo. Wil.

Bob Marek’s Bearhawk N156RM

Source: 2001 Beartracks, By Bob Marek #019

I became interested in the Bearhawk after reading an article in the October 1995 issue of Sport Aviation. I soon ordered a set of plans and received set #019. I put in an order to Airparts for the aluminum and an order to Dillsburg for the steel tubing and sheet. I took about two years of building to complete the wings.

In the summer of 1997 I retired from dairy farming. I built a new house and a hangar and was able to get back to work on the Bearhawk fuselage. Bob Barrows told me of the availability of a low time Lycoming 0-360 with a prop and a starter. I purchased the engine and replaced the starter with a light weight Skytec and also added a Nipon Denso 55 amp alternator. I located the battery under the front left seat.

After completing welding up the fuselage during the summer of 2000 we attached the wings and tail feathers and ran all of the cables to the control surfaces.

With much help from my better half Jeanie and a friend from Chapter 509 that is also building a Bearhawk we were able to get the covering and painting done before the weather got too cold last fall. Poly Fiber system was used to cover, with Aerothane on the metal and Polytone paint on the fabric. On final assembly N156RM weighed in at 1192 lbs with electrics and no back seat. I hope to get FAA inspection and the first flight this spring.

Weight and Balance for N156RM

Sample Weight Arm Moment
Left Main 553.5 -3.25 -1798.9
Right Main 545.5 -3.25 -1772.9
Tail 93 199 +18507.0
Front Seat 200 14 +2800.0
Fuel 20 gal 120 24 +2880.0
Total 1512   20615.0

C.G. = 20615.0/1512 = 13.63

% Chord = 13.63/66 X 100 = 20.6%


Pat’s Home Made Sandblasting Cabinet

Source: 2001 Beartracks, Patrick Fagan – #232

I live in the Mojave desert, north of Los Angeles. There is a lot of open, uninhabited land around my house where I like to go out and take walks, at least I did back before I started spending all my free time building my Bearhawk. Anyway, as with open land anywhere, there is always some jerk who thinks it would be an appropriate place to dump their trash. I have come across numerous illegal dumps in my wanderings.

After completing the steel hardware for my wings I wanted to sandblast them before painting. I had done quite a bit of sandblasting before, and it is such a mess, that I thought about buying a sandblasting cabinet. Before doing that, I elected to browse through some of the local illegal dumps to see if I could find anything that I could adapt to the purpose.



I found the perfect solution in an old electric oven that someone had discarded. It is perfect for the purpose as it provides a large door for access, with a built in window and seal around the edges. There is even a light so you can see what you are doing. The only problem I had with it was the dust created in side limited visibility. To solve that problem I attach my shop vac to the cabinet which not only pulls out the dust, but collects the sand, ready for another go. On another shopping trip, I found a discarded TV stand on wheels that I set the cabinet on when in use. As you can see, I cut holes in the cabinet for my arms. I bought some heavy duty rubber gloves that I cleco to the cabinet. I attached a quick disconnect fitting to the back of the cabinet for the air. The sand hose for the siphon gun passes through a grommet and into a bucket.

The project has worked quite well. I did a little something toward cleaning up my desert and managed to get something useful in the bargain.