1995 Beartracks Mailbag

This is a combined list of mail Q&A from the 1995 Beartracks issues.

Dear Bob,

You have mentioned that you have the drawings for the wings of the BEARHAWK ready and had sent some out to builders in the U.S., at first I thought that I would leave it until you had the fuselage drawings ready as well, but on second thought I too would like a set to study and perhaps organize materials and you could forward the remaining drawings later. Bob, I have a few questions which I may need to give our Civil Aviation Authority some answers to when talking to them about the BEARHAWK.


  1. What are the FLAP SPEEDS?
  2. What is the MAXIMUM MANEUVERING SPEED?
  3. Do you know the approximate GLIDE RATIO?
  4. Do you have a maximum “G” operating figure?
  5. Based on your experience so far with the BEARHAWK do you consider there will be sufficient fin and rudder area to control the thrust and torque with a 260 hp. engine?
  6. What is the range of the C of G and where is the datum?
  7. Do you have a sample C of G calculation at M.A.U.W. (Max Load) and with only the pilot and minimal fuel?
  8. Do you have a rough idea of the material costs for the fuselage and wings without engine, instruments, seating and cabin finishing?
  9. Did you give any consideration to fitting Wittman type spring steel undercarriage as fitted to Cessnas as opposed to to the bungee type? If you ruled it out for a particular reason could you tell me why. I noticed that some aircraft have treated alloy 7075 I believe in their undercarriage, I don’t know how good it is.

Regards and best wishes.

Ray Thurston – Blenheim – New Zealand

Ray,

I sent your wing drawing by air post on Jan. 19, 1995. Please mark in on drawing #1 your serial number 005. Listed below are answers to most of you questions:


  1. Flaps can be dropped at 90 M.P.H. @ 1.5 g’s. I am still experimenting with different flap settings. Currently the BEARHAWK has 5 flap settings at 10 – 15 – 25 – 35 – 40 degrees respectively.
  2. Maneuvering speed is 110 M.P. H. at 5 g’s.
  3. Glide ratio is approximately 9 to 1.
  4. Maximum “G” allowed 4-1/2 @ 2400 lb. and 5 @ 2300 lb.
  5. Rudder control vs. torque looks OK for 260 hp.
  6. C of G range 9″ to 22″ of leading edge of wing. (Note: later changed to 10.5″ to 22.5″)
  7. See weight and balance sheet (upcoming, January 1997).
  8. Estimated cost (U.S.) for the fuselage and tail tubing is $1200.00 and for the aluminum is $1500.00.
  9. The BEARHAWK has a homebuilt spring / oil system of a simple design, similar to that used on a Maule. This gear is lighter than spring type and offers far less rebound.

I hope that answers most of your questions and please stay in touch.

Bob

Bob:

Enclosed please find a check for the second half of the BEARHAWK plans. As for my progress, I do not plan on starting until June. I have however, spent considerable time studying the first half of the plans. This has naturally generated several questions which I would greatly appreciate getting your input on.


  1. On aluminum sheets, how do I determine the grain orientation of the metal and what should that grain orientation be on the spar web, ribs and wing skins?
  2. What welding technique do you use on the steel tube components, gas, heliarc, etc.?
  3. A recent article in SPORT AVIATION concerning the merits of various types of welding rod has left me overwhelmed with concerns. I have been welding for over 10 years using classic gas welding techniques and mild steel rod- I have never had any problems with my welds. I would like to know your opinion on the issue raised in this article and what type of welding rod you use.

Gordon Champion – Deep River – Ct. – serial #004

Gordon,

Grain is determined by the direction of the printing on the sheet aluminum; however, grain orientation is not a problem while your aircraft is under construction. Stress levels are within limits for either direction. Be sure to use proper bend radii to insure crack free parts.

As for my preferred welding technique I use gas welding (Oxy. – Acetylene), Tig should be OK as well.

The article you mention has raised concern with other builders also. I am recommending that you stick with mild steel welding rod. Airplanes built with 4130 tubing have used mild steel welding rod for years with almost perfect results. Alloy rod can be a big problem with cracking and brittle failure.

I hope that answers you questions. Let me know when you start construction.

Bob

Dear Bob,

The remainder of the Bearhawk drawings arrived so I have now worked out the quantities for the 4130 and other pieces on the fuselage, and have been in touch with Dillsburg Aeroplane Works.
I have ordered all the aluminum from Airparts in Kansas and that is due here in a container ship later on this month.

Meantime, I have constructed a long level work table the same as I had when I built my Tailwind, it is somewhat longer at 20′. I have also located a pair of Lift Struts, something I thought would not be available here.

Following your instructions in the newsletter I have made up a rib former and made up an end rib with some scrap to check it out complete with lightening holes, the wooden tool for flanging worked perfectly. I have a pair of fluting pliers which I made some years ago, everything else I need I either have or can obtain the use of.

I am retired so I have plenty of time, fortunately my wife likes gardening so that lets me off the hook there, although I do help by cutting lawns etc., perhaps I am a little spoilt, but it’s a nice setup. I don’t know if I told you but I was a mechanical engineer all my life and have had good experience with welding, machining and sheet metal work but have never had anything to do with aircraft sheet metal.

A few questions I want to ask you as you are a qualified in aircraft engineering.

When I built the Tailwind I constructed the the fuselage sides on the table, then stood them up in a jig and tackwelded in all the braces and crosspieces. I get the impression from your plans that you made up the top and the bottom and then fitted the side pieces, it probably doesn’t matter either way but as you are well into designing and building your methods would be useful to know.

I used oxy-acetylene with the Tailwind, I had thought of using a MIG welder this time and normalizing the welds after, what are your thoughts? Another question I have is regarding the weight and balance calculations, drawing No. 1 gives the C of G limitations also gross and empty weights etc., could you give me the length of arm for the engine, fuel, front and rear passengers and luggage if a locker were fitted beyond the rear seat I would like to know what numbers you used and when you weighed the aircraft what weights were on the mains and on the tailwheel. Could you give me your engine weight, the only Lycoming weights I can find give it at 256-265 lb. and I am unsure if this includes the mags. I note that you do not have an alternator or starter, but you have a constant speed prop, I believe they are quite chunky.

Looking at a Lycoming I0-540, they seem to weigh about 400 lb., once again I am unsure what this includes, so adding on a constant speed prop could put the total weight up to 500 lb., so is the C of G still within limits with this weight?

Regarding wing construction, there seems to be different ideas on attaching the skin, do you favour mounting the assembled spars and ribs on a vertical stand for skinning or packed up level on a flat surface?

Some of these things you may cover in future newsletters, so let me know.

Regards and Best Wishes, RAY THURSTON – NEW ZEALAND

DearRay,

We just got back from a great trip to SUN N’FUN with the BEARHAWK (1400mi.), plus another trip delivering a Lycoming engine to the Northeastern USA (1100 mi.). That’s a total of 160 hrs. on the BEARHAWK now. Good to read that you are a B.S.M.E. and past builder of a Tailwind.

Regarding the questions in your letter of April 1. 1995:

1. I built the fuselage as per plans due to the rounded nature of the sides of the fuselage. It is best to build the top and bottom frames, then jig in place and tack and weld the sides. This system seems to work best. This method will be covered in an upcoming issue of BEAR-TRACKS.

2. We use only OXY-ACETYLENE. MIG welding would not be my recommendation.

3. The length of engine arm will vary with engine used. Distance from wing leading edge to engine prop flange is approximately 56 inches. We are planing a complete weight and balance write-up in the near future. You can scale drawing #1, and reference construction drawings for other information.

Prototype: Mains = 1064 Tail = 78
  Arm = -3.75 Arm = + 195

4. The list of engines in the first newsletter should fit the C. of G. limits. The prototype 0-360 weighs 293 lb. dry (Dry is with mags and fuel system – carb or injection and without a starter or alternator). The heavier models (Lyc. 0-540) (396 lb. w/starter and alternator) will require battery mounting in the rear of the fuselage.

Sincerely,

Bob

Dear Bob,

I enjoyed talking with you at Oshkosh very much. You have a super design so I am enclosing a check for $200 for a set of plans. I think I will go with the Ford V6 engine as I can’t afford to start development work on a V8 right now. The V6 appears to be a proven powerplant and it is economical and well suited to the Bearhawk airframe.

At this time I do have a few questions for you:

1. Do you recommend that I only tack weld the sides and join them together before finish welding all, or do I finish each side while it is flat on the bench and join the finished sides together?

2. Can I use used 180 struts or should I buy new ones?

3. What parts can be purchased for the airframe that would speed up the assembly?

4. What used parts cart be substituted for new to keep the cost down?

Thanks again for a great design!

Mike Holcomb

Mike,

Your Bearhawk plans are on the way!! I hope you enjoy building the Bearhawk as much as I know you will enjoy flying it. Regarding your questions:

1. You will only need to tack weld the top and bottom of the fuselage separate, then join the two halves together by tack welding in the side tubes. The Bearhawk is different from
most other plans-built projects as you construct the top & bottom of the fuselage first and then tack weld in the side tubes. Look for more details in upcoming issues of BEAR-TRACKS.

2. You may use used 180 struts with broken ends as you will be installing your own end fittings anyway.

3. As this is a plans-built you will be building most of the parts. You may be able to ‘farm-out’ some of the work. Keep an eye on our suppliers’ section for possible sources.

4. There are a lot of used parts you can use in your Bearhawk to keep cost down. Instruments, wheels & brakes, hardware, etc. Again, look for a write-up on keeping cost low in an upcoming issue.

Best Wishes – Bob

Dear Bob,

Good news! BEARHAWK 009 is underway, with my first order for aluminum sheet for the ribs placed today from Dillsburg! Meanwhile I have been busy for two weeks building the assembly table, buying some used tools (metal band saw, floor drill press, welding clamps, air shears, bench grinder, acetylene welder) and studying the plans. My “airplane factory” is now set up on our screened back porch, once unused, with all tools under lock and key, good light and ceiling fans overhead (this is Florida, don’t forget). I’m also awaiting arrival of the four Tony Bingelis books from EAA (the fourth one is Engines). Until the aluminum arrives, I’ll be working on the rib form block, marking took and fluting pliers. I’m very excited and look forward now to each few hours I’ll get to work on the BEARHAWK. Beth is being a good sport even though she thinks I’m crazy and has to explain that I don’t even know how to fly. But not for long!

Below is a small idea that has worked out very well in case you want to pass it along. Thanks for making this dream possible with such a fine and affordable airplane. Hope you had a great time at Oshkosh, with lots of admiring interest in the BARROWS BEARHAWK.

Roy Nash

Dear Bob,

I am making up another order for raw material and I thought I would order a windshield, not that I will need it for sometime, but with freight cost to New Zealand, it pays to get a reasonable amount of material when making an order. Can you give me the suggested model of the Cessna 170 windshield I need. I also need the approximate lengths of control cable required for rudder, elevator, ailerons and trim.

There was also the matter of an increase to the VNE. I would like to have it increased to about 185 mph, your comment was about the prototype wings which were skinned with .020″ and the drawings were showing .025″ and that this would probably be OK, if this correct could you make the higher VNE official? I suppose when you have fitted the new wings to the Bearhawk you will be testing this aspect.

My final question is in relation to the wing to fuselage spar plates, do you drill and ream if required the 3/8″ and 5/16″ bolt holes out to full size at the time of assembly onto the spars or do you pilot drill only at that stage?

Regards,

Ray Thurston – New Zealand

Dear Ray,

Always good to hear from you. I just read an interesting article in the September ’95 issue of PRIVATE PILOT about flying the South Island of New Zealand. I must say I was very impressed. I think the Bearhawk will be right at home in your area! Regarding your questions:

The best looking and fitting windshield for the Bearhawk I have found is the Cessna 170B model made by L.P. Aero Plastic. The part number is #312 or #312.187 The 312 is 1/8″ thick the 312.187 is 3/16″ thick. 3/16″ would be best if you want a 185 VNE. Bearhawk.tips 2015 Note: LP now carries a Bearhawk-specific windshield that is a pre-trimmmed Cessna 170 model that will save considerable time

I will do the testing for the 185 VNE when the new wings are installed.

Control cable needed is 150 ft. of 1/8″ (7×19) and 30 ft. of 1/16″ (7×7). Scale your drawings for individual lengths needed, and leave a little extra for fitting on assembly.

When fitting the wings, I used a smaller 3/16″ pilot holes in the fuselage fittings and wing root fittings, then drilled to size on assembly.

Best Wishes – Bob

Bearhawk Transition Training

Source: 2015 Q1 Beartracks, Larry Sullivan
15q1tOnly four hours in the last six years. That’s it. Since getting my Private Pilot ticket (with tailwheel endorsement) in Nov 2008 I had only 10 hours of flying and only four in the last six years. Despite buying the 4-place Bearhawk, quickbuild kit #98 in 2007, not much was done until the last three years when I’ve been solely focused on completing my project. I’ll accept working a full-time job, trying to remain happily married, and staying in touch with my three young adult children as an adequate excuse for my low flying time.
I knew I was rusty when I rode with my friend in his C150 and felt like turning downwind to base and lining up for final was a huge struggle. My Bearhawk project is nearing completion (really!) this spring and I was struggling with the idea of doing my own first flight. I have a new Lycoming EXP-IO390, an 80-inch constant speed propeller, and a Dynon Skyview glass panel. The J-3 Cub certainly doesn’t compare, so I’ve been thinking about having Tom, a cropduster friend on the airport with 50,000 hours do the first flight and he was quite willing. In addition to all the first flight issues, my engine needs a proper break-in, making the initially testing that much more complicated.
At the same time one of my friends on the airport suggested letting someone else do the first flight was like letting someone else take your wife on your honeymoon! I guess I don’t really look at it quite that way and my ego isn’t that big, but I wanted to feel comfortable and safe doing my flying in the Bearhawk. It was fortuitous that I recently spotted an article in Sport Aviation indicating that Jared Yates has been given FAA approval to provide Bearhawk transition training in his Bearhawk N805TB in Hickory, North Carolina. This was perfect timing for me, so I jumped at the opportunity. I had met Jared a number of times over the last six years at Oshkosh, spoken with him in regards to BearhawkStore.com orders and knew him to be a thoughtful, mild-mannered person with whom I felt very comfortable. I reviewed the syllabus he prepared and it looked perfect for my needs. We looked at our work schedules and I was able to arrange a stopover in Charlotte for four days after visiting my in-laws in Florida.
Jared met me at Charlotte airport in his yellow “Pac-Man” 2003 Ford Focus and he brought me back to Hickory, which is about 45 miles from Charlotte. He was generous enough to offer the car for my use during my four days in Hickory. I also couldn’t beat the price of lodging which was with Danny, a fellow aviator in Hickory who had a spare room. Danny, also a former commercial pilot and CFI, made me feel at home and gave me a set of keys so I could come and go as I pleased.
We started ground school on the way back from Charlotte and reviewed our expectations for the lessons that were to take place. We knew that the next day was going to be windy and rainy and not suitable for flying but we decided to try to get at least an hour or two in right away. We stopped at Danny’s house, made acquaintance, dropped off my bags, and headed right to the airport.
Jared is an experienced commercial pilot who obviously loves flying enough to have built his own Bearhawk in his spare time. With a wife (who actually provided hands-on building help!) and two lovely little girls who like to fly he obviously has this aviation thing figured out. The hanger thing is another story. For those that have not seen photos of Jared’s hanger on his builder’s log website it’s rustic with corrugated metal sides and roof, sliding doors, a dirt floor and gaps that make large mammals laugh at the attempt to exclude them. There are even lawn ornament deer and a few baby walkers. This portion of the hangar description has been redacted at the discretion of the editor. Nevertheless, there was N805TB in good working order. The same plane I had seen packed to the gills in Oshkosh this last summer. His Lycoming 360 engine from Bob Barrows with a 76-inch constant speed propeller and Dynon 180/100 glass panel was as close to my setup as I could hope to fly.
In the air on the first flight Jared let me practice handling maneuvers in order to get a feel for the adverse yaw, sensitive trim and stall characteristics. All very different from what I remember from the Cub. The next day we knew would be a non-flying day with rain in the a.m. and strong winds in the p.m. In fact there was a little rain as we headed back to E40 at the end of our first flight. We agreed to meet Monday for lunch and then do some ground school in the afternoon.
15q1rThe weather was as advertised on Monday, and after the lunch of enchiladas, chips, and salsa with Danny and Jared’s daughter Felicia we headed to the hanger and sat in lawn chairs in front of a propane heater for ground school. The thing I really appreciated about Jared’s instructional style is that he frequently checked with me to see if he was providing what I felt I needed. De-briefing at the end of the day and planning the next days goals allowed me to prioritize my goals and sleep on them overnight. We took several breaks out of the airplane during actual flying which helped keep me relaxed and better able to focus and less fatigued at the end of the day.
The real work and learning took place on Tuesday when it was calm and 30° F at 8:00am. The wind never got to more than 5 mph all day. It was sunny and scenic. However, I didn’t have much time to enjoy the scenery. Ground handling was the real challenge for me. First was on the expansive grass runway at Shiflet Field (9A9), and when I got a little better, over to the pavement at Hickory (HKY). High-speed taxing with the tail up and transitioning to a stop was initially frustrating and scary. Jared let me experience my directional control mistakes to the degree that he safely could, and had to salvage a few near-premature runway exits. He even let me have a low speed embarrassing ground loop on the pavement.
My confidence was waning but he showed no frustration or concern, which helped to me press on. I finally recalled the “Tap-tap-tap” technique that I was taught in the cub and my inputs became quicker and less prolonged, but I still occasionally put in the wrong input. It wasn’t until I realized that I had not been focusing my vision further down the runway and defining clear visual references with the cowl that I finally began to respond consistently and quickly without thinking about my feet. Getting in the pattern, setting up, and sensing the decent speed with two notches and without flaps seemed relatively easy especially after I retrained my eyes. Overnight I re-lived the difficulties and the successes of the day and realize that the ground control was my main concern.
I was still anxious about it when we met Wednesday morning. Another perfect day allowed us to get right to work. We went to a narrower grass runway at Lower Creek (NC27) about 15 minutes away. On the way, we set up a three-notch-flaps descent and slowed the plane to 50 knots so that I could feel the effect of full flaps prior to landing. NC27 has a ridge of tall trees on one side and a right pattern which was a different feel, but I applied my retrained eyes to these landings and felt much more comfortable. Landing with the extra flaps was even easier because the time in transition from flying to full stop is less, but even wheel landings at 65-70 knots still seemed easier than they had the day before. I seemed to have gained the confidence I had almost lost the day before. Jared even “shed a tear” as he put it with one of my best landings! Little did he know how good that made me feel. I now feel confident I can handle my Bearhawk but I still think, given the new engine and limited experience in similar planes, I may have Tom the crop duster do the first flight for me.
Jared and I de-briefed over lunch and he signed me off for my flight review and successful transition training. Since he was leaving the next day for a work trip, he said he would have me drive his car back to Charlotte and have his wife drop him off there the next day. I was able to move my flight up 12 hours to get back to Wisconsin early and I dropped the “Pac-Man” off at Charlotte long-term parking feeling like for what I had received I had gotten a real bargain!
See a video of some of Larry’s landings at http://youtu.be/qf_8kOV47o4
Editor’s note: The Bearhawk Transition Training Course is designed to help demonstrate Bearhawk-specific characteristics to otherwise current and qualified pilots. Training with a non-current pilot is less cost effective and less than ideal. Fortunately Larry is a fast learner, and almost all of his experience is in tailwheel airplanes. The ideal plan is for prospective transition students to gain currency in any other type of airplane, preferably a tailwheel airplane, before beginning the program.

On Becoming the Official FAA Poster-Children for Messy Hangars
15q1sA brief sidebar by Jared Yates
We decided early in our building project to construct a public, online building log. This comes with both benefits and drawbacks of course. The benefit is spreading information to fellow builders about how we did things and what mistakes we made. One drawback is the possibility of disclosing a little bit too much information.
One day a few years back I got an email from an employee of the FAA. The nice lady worked in the safety training office, and she was preparing a PowerPoint presentation about hangar safety. She was looking for an image to use as a bad example– how not to keep a safe and clean hangar. Her Google images search brought her to the photo above, which is has a caption that includes the words “messy hangar.” She was writing to ask for permission to use the photo in her presentation, and I agreed. Obviously keeping a hangar safe and easy to evacuate is important for a flying airplane, but I’d say that it’s less important for a construction project in progress. Nevertheless, she did indeed incorporate the photo into her training materials. One of my local EAA friends was attending a safety seminar a few months later and saw the presentation, and of course immediately recognized our hangar and project. We all got a great laugh out of it, and now we can proudly say that our hangar is not just messy, “it’s officially FAA messy.” Be assured that these days, it is much more organized, and I promise that the concrete deer figures are completely temporary.

Bearhawk 4-Place Transition Training Available

Source: 2014 Q4 Beartracks
14q4zDo you need to receive dual instruction in a Bearhawk for transition training, but don’t have access to a Bearhawk? Jared Yates has received authorization from the FAA to provide dual instruction in his Bearhawk under a specific list of limited circumstances. Training candidates must be current, tailwheel-qualified pilots.
Read more at bearhawktraining.com, or call 828-308-1543. Continue reading