BD-4 NEWSLETTER #20
Roger D. Mellema
17605 SE 288 PI.
Kent, Wa 98042
PH 206-631-5324
July, 1992

Dear readers,

I just decided that there was time enough to get a newsletter out before my vacation and Oshkosh. I have a lot to share with you - some of it not the best of news.

I heard from Bob Warfield from Denver. He crashed his V-6 powered BD. He has been ready to fly for a long time and had his engine well run-in. His was a sorta Javelin conversion. He made his own reduction drive using sprockets from Gates and a welded up tube truss. The ratio was 1.67:1. His engine was a 1983 with the original style Ford pistons (probably 8.6:1 compression). He used a 350 cfm Holley after trying a 500 cfm. The 350 was much more responsive to throttle movement and the electronic lean worked much better. Of course, he is operating at 5000 ft elevation and the lower air mass might make the smaller carb work better.

He started out using a 70 x 62 prop and could turn it up to 6000 static. He then went to a Props Inc. 68 x 71 and could still turn it 5500 rpm static. ,

He used a Mallory non-CD Infra-red triggered ignition set at 32° max spark advance, and ran all of the exhaust pipes (6) out under the firewall. The radiator used was from the Buick powered V8 airplane and was 5" x 24" and 2.5" deep (4 tubes). He only had 2, 3" diameter blast tubes feeding the radiator and the tube inlets were quite a distance from the rear of the prop. The radiator was in a plenum so that all the air coming in went to the radiator. There was another inlet around the spinner for engine compartment cooling. The engine ran 200° on the ground in moderate temperatures. The water pump was modified only by putting a plate on the rear of it. A liquid to air oil cooler was used to decrease the load on the coolant radiator.

The accident was on the first flight and was not due to the engine. He lifted off at 60 mph, accelerated to 70 and held it there. He was in a very nose up attitude at about 30 to 50 ft (out of ground effect) and was not climbing. He admits that the accident was pilot error. The right wing stalled when he input aileron to stay over the runway he partially recovered and mushed it into the ground. The right wing tip hit first and the spar was bent some. He suffered a small cut and some bruises. He does not intend to re-build.

I have purchased the wreck for the usable BD parts. Dave Blanton mentioned that up stops may be needed to limit the stabilator travel and so, preclude this type of accident. This doesn't sound like the right solution to me. There always has to be enough elevator action so an airplane can be stalled for landing and I don't find the stabilator as being too powerful. I think what is really needed here is better methods of getting pilots trained enough to fly the BD-4 and/or to have BD-4 experienced pilots to help during the flight test preparation and flying. This accident could have easily been avoided by flying a proper 90+ mph climb-out. An airplane that stalls at 67 (clean) should never see 70 mph in normal flight. This airplane did not have the long wings which might also have saved the day.

I know what your ego's are saying. Most of us suffer from the same ego problems and that means we all want to be test pilots. The problem is that we do not foresee anything but a successful first flight wherein all obstacles are overcome by heroic leaps of genius, and sheer cunning (and our friends and relatives are greatly impressed). That is how I had it pegged anyway! What did I do the first time around? I am not going to tell you (but it was more on the dumb side)! As a high time, older, wiser BD pilot, I was a bit nervous when I test flew my second BD-4.

Let's try here to figure out what is most impressive to our loved ones. Being seen as an intelligent problem solver that considers all the angles and opts for experienced help or who costs them much grief and several thousand dollars in funeral expenses. Can you imagine what they will say if you hurt yourself? If you can find a trusted, experienced, conservative test pilot to fly the first couple of hours for free or even a couple hundred bucks (consider the low percent of your total investment) you would be considered a genius rather than a failure. I like brains over guts.

Be sure you don't select a pilot that just talks a good story and wants to stroke his ego. You want someone who flies frequently and has experience in several aircraft.

I think there are some half way measures that might be employed here. First of all - get a ride in a BD-4 and see how badly you scare yourself (many people really do). It is not a bad or difficult airplane but it is different! Most of us are trained and fly airplanes that have a much lower wing loading than the BD. This is why I stress that low time pilots should fit the long wings on their BD-4 for the flight test period. This is a very simple addition and does not require extending the aileron or flap. The extension can be installed and removed easily at any time. Even high time pilots such as Ray Ward have found the long wings to be a real joy to fly with.

At the very minimum, you should read a good flight test article like was in the February-March issues of Kitplanes by Jim Loyd.

A second thing that is cheap and easy is just to talk to a high time BD pilot. I would be happy to tell you who lives in your area. He can tell you all the things like how the BD-4 (with short wings) climb angle is quite flat due to the fast speeds needed for best rate of climb.

A slightly more involved option is to have an experienced BD-4 pilot help you inspect your airplane and do some high speed runs down the runway to see if performance meets his expectations. I don't feel comfortable seeing an airplane fly until a few experienced builders look carefully at a new airplane for a couple of hours. I can guarantee that even then a couple of small things will be missed. I know it is hard to take "correction" from others but please put down your ego for a bit and consider all recommendations. Please don't invite anyone out to visit while the inspections are going on. There are plenty of distractions that will already get in the way of business.

The FAR's do allow "necessary crew" aboard the aircraft during flight test. Some people have interpreted this as to allow two people on the initial flights, one to fly, and one to monitor gauges. In this way an experienced BD pilot could go along to help (be sure you settle who is in charge in an emergency).

It may make you feel better to know that after your first baby (homebuilt), you tend to relax and would just as soon let some other pilots do part of the flight test hours. They sometimes will even buy their own gas!

I hope you will give some thought to what has been written here as none of us like to see BD4's come to grief. It makes it look like a bad airplane (which it isn't) and it makes insurance difficult or impossible to get.

We recently had an incident here at our airport. Rick Graf went out to run up his engine (Ford 357) and make sure it would run at full power. He was going to do a slow run up the runway but it turned out a lot different. At full power,the engine began running rough and he looked down to adjust things. When he looked up, the airplane was starting to ground-loop. He successfully saved the airplane from several ground loops but ended up nosing it over and collapsing the left main gear.

Dues
Please take a look at the symbol on the mailing label. If it is a "+", you will receive one more issue. If it is a "=" or a "*"you are doing all right. A "@" means you are way behind.

Successful First Flights
Chuck Ingalls from Port Townsend, WA recently flew for the first time. He had an experienced test pilot do the first flight and give him an evaluation of everything. Chuck is now flying off the hours. He has a O-320 Lycoming and a fixed pitch prop. Jim Huber and I went to look over Chuck's BD a couple of months ago and found just about everything ready. He had a nose wheel (Scott 3200) that had almost no friction in the swivel. As you know this is an invite to wheel shimmy and losing the whole nose gear. He also has some friends with Varieze's who convinced him that the carburetor air inlet and filter should be on the firewall and under the engine (where all the hot air goes). On a Varieze, this area is the cold air side of the engine as they use updraft cooling. Chuck fixed these things and now should almost be done flying off the hours. Congratulations Chuck!!!

John Dornbos was recently diagnosed with a very serious illness and we in the Seattle area have committed to helping him finish his BD-4.

John and I went to California a couple of years ago and picked up Klaus Heddergott's bent BD4. I don't know if you remember but Klaus was doing a taxi test when the brakes faded and he went into a soft over-run and bent the airplane some. I believe that was in 1978 as I remember him telling everyone at the Oshkosh meeting.

John has fixed the damage, made it into a taildragger, installed a new instrument panel, and installed an O-360 Lycoming engine and fixed pitch prop. These other parts came from other BD-4's that John has bought and sold. The engine is a converted helicopter engine that has been converted just like Steve Mahoney did with his.

Many volunteers got together to build up the Murphy metal wings, install 25" wing extensions and tips, built a new flap and helped finish up many small details. Would you believe that there has not been one single leak in the fuel cells? We did all of this in less than 6 weeks and John flew the airplane on June 27, 1992., There was a big crowd at the airport for the first flight (not recommended) and I believe 5 video cameras ready to record his every success (and failure). John had a definite flight plan written down and followed it very well. He lifted off after a very short run and did a fine job of landing. He is now working off the 40 hour test flight period.

A 2-Easy owned by Ellison Throttle Body company flew chase and it was fun to watch it take up most of the runway when it took off. He also couldn't go nearly as slow as the BD.

John said that the BD got up to about 185 mph true at 5000 ft. The stall speed is about 55 mph indicated and very gentle. This engine has a 2900 rpm red-line when it is used in a helicopter (it also has a different profile on the cam which changes the torque curve so that 180 hp occurs at 2900 rpm). John said that he had 24 inches of manifold pressure and 2850 rpm when doing his speed run. The prop now being used is supposed to have 60 inches of pitch.

John and his son, Grant are expecting to make it to Oshkosh this year. The wings will still be in "Boeing primer green" and some bare fiberglass but it flies just as well that way (any way to Oshkosh is the right way).

Tachometer Caution I was reading the report on Shirl Dickey's E-Racer and noticed a fact that might help some of us avoid trouble. He thinks that one of his engine failures was caused when an electrical tachometer somehow shorted and grounded out his ignition system. He has now gone to a mechanical tach. Another possibility would be to use one of the tachs that get their signal from the fields around the alternator. There are other non-intrusive tachometers that count the prop blades or a white/black pattern on the flywheel.

Paint Tip
John Brecher has had some recent experience with a new paint. It is called R & M Paint and is made by BSDF Company. It goes on very dull and then uses a gloss overcoat. John said that it is the best paint he has seen.

Pulleys for the V-6
Walt Beecher is having light weight aluminum (hard anodized) accessory drive pulleys made for the Ford V-6. The accessories slow the alternator and vacuum pump down to the proper rpm and about one half of the weight will be saved. You will get 4.52 inch crank and water pump pulleys, a 2.727 inch alternator pulley, a 5.0 inch vacuum pump pulley, and 1 small belt for about $196.00. The real benefit comes from the extra sheave on the crank and water pump pulleys so you can run a second belt to assure you of cooling even if you throw one bait. The pulleys will be hard anodized to reduce wear and will not require the engine to be moved forward. It will be necessary to turn the water pump in the opposite direction (the pulley will be cut for the ribbed side of the belt rather than the flat side). This should not make any difference to the cooling as long as the centrifugal water pump vanes are not canted' (they should be axial to the shaft). Engines by Brantly is now investigating just what water pump impeller is needed.

One belt will go around the crank, water pump, alternator, and vacuum pump pulleys and the short belt goes around the crank and water pump pulleys. The alternator and/or vacuum pump can be moved to set the belt tension on the long belt. It looks like the vacuum pump could be mounted on the left (above or below the alternator). The short bait is just the, right size to fit around the crank and water pump pulleys.

Order from: Walt Beecher, 29 San Jacinto, Galveston, TX 77550, Phone 409-7628125.

Noise
I have been trying to convince some recent callers that it is not worth insulating your BD cabin for noise. It is a worthy goal to get it quiet enough so that you can talk and so that you are not excessively fatigued, but the penalty in cost and weight are high. Of course, headphones are not light or cheap. It is more acceptable to make a quiet cabin if you are making a 2 place BD. Remember though that you still have to have the noise of a radio blasting your ears almost constantly (unless the pilot wears an earphone for this purpose). .

I find the wind noise more troublesome than the engine noise. Wind noise requires very good sealing of the doors and flap/aileron holes. This almost demands a pneumatic seal for the doors or a mufti-point latch down system. I have never gotten my doors to seal the way I want. The idea I wanted to add here was given to me by a builder in Canada whose name I have forgotten. He couldn't get the wind noise down until he used alight twin trick (we do go the same speed). He installed very thin plexiglass panels on the inside of the door frames (0.75 inch separation). He found this to make a huge difference in noise and you might want to try ft. Steve Mahoney has done this on the front quarter windows.

There was an article in a recent "Popular Science" that was of some interest to us. It seems that the new 300 hp LT-1 Corvette comes from the factory with Mobil synthetic oil as standard. It is claimed that the use of this oil gives longer engine life and eliminates the need for an oil cooler. I would guess that under this set-up, the engine does run hotter but the oil at least can take it without coking.

I used Mobil t for several years in my O-360. It started to use more oil than it should have and I was thinking of changing back to Aero oils when an article came out that explained the problem. It seems that pure synthetics sometimes have this effect (at least in aircraft engines). The solution is to use a blended oil or just use Aero oil for 20 hours every 200 or 300 hours.

I am now wondering if Mobil 1 could be used in the V-6 to avoid the extra weight and cost of an oil cooler. Does someone want to do an Experiment? Remember that synthetics are most used where the conditions are so extreme that mineral oils cannot be used.

Wants
Austin Perry would like information or parts for the Barnhardt or Murphy nose gear.

J. W. Brewer has a dynafocal engine mount for sale.

Props
Bob Warfield reports that a V-6 with a 1983 compression ratio (8.6 to 1) can turn a 70 x 62 prop at over 6000 rpm. He then went to a 68 x 71 Props Inc. fan and could static turn it to 5500 rpm. This performance was at Denver which is a mile high. The engine looses some power but the air is also thinner and so gives less resistance to the prop. Props Inc. claims that their 71 inches of pitch is really like 74 in some other props.

Radiators
I now have my aluminum radiator installed under the rear of the V-6 on my BD. I bought an aluminum core (no end caps) for $115, made up 6P61 T6 end caps, and had the welding done on the end caps for $120. I cut the radiator into three pieces by cutting in the direction of the tubes and right down the center of a tube. I now have the three pieces of radiator connected in parallel. The air does have to go through all three thicknesses of radiator in series. This means that the air will not pick up quite as much heat form the last core as from the first as the temperature differential will be less. Air temperature only increases a few degrees when it passes through each core. The air will normally not be substantially heated even after three cores.

The total weight of the radiator, the water in it, the header tank, and the water in it is only 13 lbs. The weight of the copper/brass radiator made in Arizona is 26 lbs (and $300) just by itself.

I have been doing a lot of runs up the runway and find that I can run quite for some time before the temperature gets to 190° F. I still do not have a pressure cap hooked up and so tend to loose some fluid. I have a hastily made inlet opening and outlet ramp hooked up which really increased the cooling. I have started the cowling and am now working on the inlet lips. A friend from chapter 441 has given me the airfoil type to use to shape the inlet lips.

I wish all of this had been flight tested - but it will be before the next newsletter.

Stan Wilkins wrote that it is possible to reverse the oil pan so that the radiator can be installed forward further. You just cut the pan off a couple of inches below the flange, reverse the bottom and reweld. Stan also wrote to ask what the official clearance is for the pistons. I have mine fit to about 0.005" (which means 0.0025" between piston and cylinder wall on each side). Blanton likes about 0.007 or so.

Letters
Noel Dunlap sent pictures of his new cowling. He did a couple of interesting things with it. He made a hinged door by the exhaust outlet so that he could get the bottom of the cowling on easily (and not have too large a hole for the exhaust pipe). He also made the cowling extend below the fuselage so that the cooling air would come out parallel to the bottom of the cabin.

This should help with cooling flow and drag reduction. Steve Mahoney has fought the "hot" engine problem for a long time. He finally put a "draggy" exit ramp on the bottom of the cowl and found that cooling was much better but also that he gained about 4 mph in cruise.

Beryl (Chip) Cotton may be the first person to install Continental power in a BD-4. He is looking at an O-470 with Cessna rod gear, extended fuselage, and wing extensions.
Robert Bollinger is now testing an Aymar-Demuth 70 x 68 (really more like 70 x 74) prop on his V-6. He can pull 3500 rpm (2200 rpm prop) but is still using the original car exhaust system. This prop is also used on a 200 hp Lycoming racing engine.

This sounds about right as I can get 3600 rpm (2250 prop) using a Performance Props 71 x 76). I think this sounds about right for static rpm, Robert thinks he would like 4000 rpm (2500 prop).

Ken Mitchell sent me an update on his V-6 powered BD-4. He is now using a Pacesetter 72 x 74 and likes it better than his Prince 67.5 x 74. He needs about 300 more rpm with the Prince to get 155 mph ind. at 5200'.
At 9400' and 4000 rpm, he gets 160 mph IAS with the Prince and 180 mph with the Pacesetter. He also gets almost twice the climb rate with the Pacesetter.

He really likes the Blanton conversion and feels so safe that he sometimes flies it over Utah's mountains in the middle of the night.

Ken would like to try a scimitar prop - anyone know where to get one?

As I went to Denver to pick up Bob Warfield's BD, I stopped in Bountiful, Utah for dinner and Ken came over to talk for awhile. He admitted that he finally put 9 : 1 compression pistons in his V-6 and found a huge difference in power - he really recommends it.

George Wittet has now tried his fuel system out and really likes it. He installed 2 Facet electric pumps in each wing root - one connected to each tank outlet. When the engine is started, the pumps have to be on. Apparently the ball check valves set on their seats when the bird is at idle and won't free flow until started with the pumps. After starting, they flow over 17 gph from each with the tank pumps off and 36 gph with the pumps on. George cruises with the pumps off, turning them on for take-off and landing.

John Stewart , 2715 San Juan Loop, Holloman AFB, New Mexico 88330 is looking for metal wings for his BD-4. He will buy them unbuilt or built and may even buy a whole airplane just for the wings.

John has owned the plane since 1981 and have put about 400 hours on it in the years that he had it flying. He has been all over the country with it. In '83 he was the last one off the runway at Oshkosh as a thunderstorm blew in and ended up with a 20 to 30 knot tail wind during the take-off roll. He once rode wave lift off of Pikes Peak to over 15,000'.

Tim McGinnis is now satisfied with his "one-way fuel flap valves" for the inboard fuel cell in each wing. The idea is to slip the airplane to "pump up" the inboard cell. The valves are made from simple pieces of aluminum and gravity is used to hold the valve flap close to the seat. When the airplane is slipped, fuel will flow through the valves. The pressure of the fuel in the first fuel cell will then hold the valve shut. with this system you should be able to have good safety during landing even if you are very short of fuel. You just have to "pump up" the inboard cells by using the rudder to make the Turn and Bank ball go off to each side.

Ray Ward sent a sketch of how a metal BD-4 wing rib could be made using metal angles (everything else on the BD is made of angles!). He thought of the idea after reading an article on the Skylite in the 12/91 Sport Aviation (page 44). He suggests using 0.032" thick angles.

The "collar" that fits around the spar could be 0.032" thick Aluminum about 2 inches wide. The sketch below is just an example, it has not been engineered. The fuel tank ends would have to be solid aluminum.

Ray also sent pictures of his airplane taken at Kerrville fly-in. They really look great. Climbout is at 5500 rpm (engine) and cruise is at 3500 to 3800 rpm. Cruise is at 230 mph TAS. Once everything gets finished, Ray expects over 240 mph TAS. Everyone likes the dragster roar on takeoff. It is quieter and smoother than the IO-540 in cruise.

You wouldn't believe the number of calls I have gotten from people who want to build a BD up like Ray's. People just love big V-8's!

Paul Wood needs: current pilot to shoot some touch-and-goes with me in my high-performance, tailwheel BD-4. Wages, travel and expenses cash. Call Paul Wood, collect, 8 a.m. to 10 p.m. Nebraska time, 7 days. 402-486-3810

Walt Beecher sent along information about Thermo-Tec products. I have seen a lot of people using the exhaust header and tailpipe insulation wrap. It looks like this stuff is made out of Nomex. It is used to keep the heat out of the cowling. It supposedly also makes the tuned headers work better as there will be higher velocity gasses going out of the exhaust stack which better evacuates the exhaust out of the next cylinder to be fired. JC Whitney and Summit Racing carry this product.

For Sale

BD-4 N58266 180 hp Lyc w/CS prop, 430 hrs since new. King KX 1758 radio. Red/White like BD demonstrator. Photos available. 203-635-4058

Ken Mitchell has a Prince 67.5 x 74 prop for $200 plus freight. It will be sold in an "as is" condition. The Kevlar trailing edge is breaking off again. Ken also has a BD nose gear assembly with a 10 inch wheel (replace tire) that is full swivel. , He will sell it for $200 plus freight. BD-4 wing tips - $30, wheel covers - $100, oil cooler (dirty; no leaks) - $10, Stabilator tips - $10, set of 4 dynafocal rings from bent mount for Lyc Q-235 through 10360 - $35, set of Cleveland 600 x 6 wheels with brake discs, large nuts for cover and BD axles attached, no bearings, seals, etc (good as new) $250. Also may sell Interphase Locator Loran.

Solid Landing Gear Links

Would you believe there is still a better way to do solid links? I think Steve Craigle has improved again on a good idea (see Figure 1).

Steve has also optimized the placement of the rudder pedals/brake cylinders. He was interested in a configuration that best keeps the top of the pedal (the brake) vertical throughout maximum rudder deflection. I always thought it was good to get a little brake actuation when nearing maximum rudder travel. That way I don't have to actually think about pushing on the brakes when trying to control a ground loop? See Figure 2 for the dimensions that Steve came up with. Shims can be placed between the gear and the link to change the angle that the gear comes out of the fuselage (and the camber of the wheels).

Figure 1 & Figure 2



The landing gear box must be reinforced in order to go to the gross weights now used. This drawing will give you the basic design that most people use. Some of these changes are included in the later sets of plans.

1. The quarter inch thick plate that fits on both sides of the gear box must extend all the way to the side channel.
2. The side channel must be reinforced with a 1/16" thick piece of 2024 T3 AL. This is to keep the countersunk boltheads from moving around in the side channel.
3. The angles that tie the landing gear box to the side channels were very inadequate. They should be increased to the size shown.
4. Do not fit your landing gear box and cover so tight to the side channels that you cannot remove them. This does not increase the strength of the system.