Issue 15, January 1988

Dear BD-4 Builders and Owners,

First of all, my family and I hope you had a very happy holiday season and are having a prosperous New Year! This of course means that you have enough money to get your BD ready for the BD-4 TWENTY YEAR CELEBRATION at Oshkosh this July. I have been encouraging everyone I come in contact with and have had a lot of people tell me that they are cleaning up their airplane and plan to be there. Hugo Schneider assured me that he and others are working on different little things to make the celebration successful. It looks like the banquet will be on Monday night at 7:30. In order to reserve the banquet hall and arrange for the 20th anniversary momentos such as patches, plaques, and banquet program, we will have to pre-register. At this time the cost for the pilot will be $25, and guests will be $12. If you don't get Hugo's newsletter, you can arrange for your tickets by contacting him at: 2711 Brookside Blvd, Jackson, MI 49203, Phone 517-789-7245. The tickets will get you the momentos, the banquet, and defray the costs of trophies etc.. A banquet program is being put together that includes words of wisdom from Jim Bede himself and comments from some of the very earliest builders. Janice Brekke is working up a BD-4 history that should be very interesting since she has been around since "way back when". There will also possibly be a forum tent reserved for a program.

The regular discussion group will meet on Saturday, Sunday, and Tuesday evenings. The discussion meetings will be at the University. The exact time, building and room will be displayed in the window of Hugo's BD-4 as usual. For those of you who have never been to these meetings, we usually just bring up anything about BD-4's that we need help with or are concerned about. Usually you will get several probable solutions to your problem. Everyone looks at things from a different perspective and it makes for some very interesting discussion. There are some things that we just never seem to solve so maybe you can help.

Gene Selchow has set up a very interesting outing for any BD-4's that feel like a flying adventure during Oshkosh. Don't say NO just yet. I know how nerve wracking it is to contemplate tangling with the traffic and Fisk arrival but when you get together and talk it through it really is not difficult. Gene has arranged a flyout to Delevan Lake lawn Lodge located at Latitude 42-37-55, Longitude 88-36-05 on the Chicago sectional (this is 81 NM from Oshkosh). The airport is hard surfaced and is 4400 ft long. Brunch and shopping are available for those who don't talk airplane and formation flying, air-to-air photos, and "performance comparisons" for those who need to (lets not tell Ray Ward about this). Those who can't get their birds to Oshkosh can beg rides or drive down and join the fun. Departure from Oshkosh is scheduled for Tuesday at 0900 with departure from Delevan-Lake lawn at 1300. Arrival back at Oshkosh before the airshow for those that haven't seen it yet.


I have a new location at the Boeing Company and can take short calls during the day. The new number is 206-248-5534. This is a "hello" phone so don't be put off by the lack of identification when the phone is answered. No one will answer any questions but will take messages.


Robert G. Hoey
1353 W. Kildare
Lancaster, CA 93534

I have been hearing stories about the BD-4 fuel system since the beginning so I guess I might as well put in my two cents worth. My fuel system is AS PER THE ORIGINAL DRAWINGS. Both lines run down the forward post, tee together at each corner of the instrument panel, connect to a left-right-off fuel selector, then to the gascolator and to the engine-driven pump on my O-360. I have 400 hours on the airplane and have had no INADVERTENT fuel starvation problems. I did some mockup tests before installing the lines in the airplane (a clear milk bottle with some clear plastic lines and some water). Three things were fairly obvious from these tests:

  1. You've got to keep BOTH lines submerged or you'll pull air through the system.
  2. You've got to keep a positive head on the carburetor (carb inlet BELOW the fuel level by about a foot) if you expect the engine to run in the event of an engine-driven fuel pump failure.
  3. Once you've unported a line, a bubble may remain in that line (from the tank to the tee) even after you've refilled the tank.

Minor arching of the lines (like forward over the door), longer and lower lines (like aft around the door), larger lines, relocated tees, etc. DID NOT alter these three facts. A large sump tank would delay the air to the carburetor, but if it's down low in the fuselage you are dependent on that engine-driven pump for positive pressure to the carb whenever one of the 4 lines is open. I have run several flight tests on my BD-4 by running a tank dry at various attitudes and power settings (at altitude of course). The system seems to behave just as expected.

  1. It takes 4 to 5 seconds for the engine to restart after switching to a full tank.
  2. The system is very sensitive to pitch attitude as the tank approaches empty. With about 5 gallons remaining I have unported the forward feed line in a relatively normal climb attitude.
  3. The system is also very sensitive to SIDESLIP as the tank approaches empty, and this is the ace-in-the-hole. I have run a tank dry in a zero-sideslip climb and successfully restarted the engine AND CONTINUED THE CLIMB for about two minutes by immediately pressing the rudder on the same side as the tank. If feeding from the left tank, step on the left rudder. The side force produced by the sideslip pushes the remaining fuel against the inboard rib and re-submerges the two feed lines. This process also takes 4 to 5 seconds before the engine will catch.
  4. In smooth level flight with the ball centered a tank will unport with 2 gal of trapped fuel remaining (I have three bays per side). More fuel will be trapped in turbulence.
  5. In smooth level flight a 1/2 ball width sideslip away from the tank that is feeding (left rudder for left tank), will allow the tank to feed until less than 1 quart is trapped.
  6. Although I have never experienced a hesitation in flight due to the "bubble" after unporting a line, I have seen solid evidence of this when draining fuel through the gascolator after refilling a tank which had been run dry.

With all this firmly in mind I have developed the following procedures for dealing with the problem on my BD-4:

  1. Don't perform steep climbs or descents at low altitude on a tank that has less than about 7 gallons in it.
  2. When flying a long leg, run one of the tanks as close to dry as possible while still in cruise by sideslipping slightly. This maximizes the amount of fuel in the remaining tank for a possible go-around. Notice that this is NOT consistent with those who recommend a BOTH position on the selector. I'd prefer to have one dry and six gallons in the landing tank rather than feed from both tanks with 3 gallons in each.
  3. If a line has been run dry (that is, momentary engine hesitation while you switched tanks) always drain a quart or more through the gascolator with the selector on that same tank after you refill. You may observe air in the line and can tell when it flows full again.
  4. If you're running low on fuel, you're already on the fullest tank, and the engine quits, push on the rudder on the same side as the feeding tank.

Running out of gas is not a problem which is unique to BD-4's. With a reasonable fuel reserve in the airplane and a little common sense I feel that the fuel system is as safe as any other high wing, gravityfeed, integral-tank system.        rgh


913 Angela Court
McMinnville, OR 97128

Over the last two years since I got my BD flying I have been trying to look for a way to make it quieter inside the cabin. I now have two small children that frequently accompany us on long cross-countries and I worry about possible damage to their ears. The children will not wear headsets and the one-year old usually will try to eat the ear plugs we put in her ears. The OSHA requirements for continuous exposure is 80 dB. As you can see by the graph my BD (579 SC) far exceeds this. So do just about all small aircraft (note the Cessna 150 on the graph).

To start with, I borrowed a sound meter from where I work. I don't know what frequency spectrum this meter is looking at, but it is used to see if noisy work environments meet OSHA requirements. I then went out and measured the cabin noise of my airplane at various air speeds. All measurements were made made at 4000 feet MSL, and all air speeds are in indicated mph. The microphone input of the sound meter was held at the pilot's ear level facing forward.

My BD-4 has no interior insulation (just bare sheet metal on the inside) except for the firewall and side doors where I have 1/2 inch of styrofoam. The airplane only weighs 1130 lbs. empty. The engine is a Lycoming 0-360 with the standard muffler BD provided in the kit.

The first thing I tried was to add some fences on the side of the windshield to try to eliminate some of the turbulence on the side windows caused by too small a radius on the front windshield corner (see earlier newsletters). This helped some.

I then wanted to see what was possible by adding some insulation on the cabin interior so I turned to my friend Colin Powers in Independence, OR. Colin has the quietest BD-4 I know of. It's quieter than a lot of factory airplanes I've ridden in. Colin has worked hard to get his noise down and it shows (see 239CP on the graph). He has bound 1 inch foam on the fuselage sides and has insulation on all surfaces, a full head liner, special jute under the carpet, and 2 inches of foam on the firewall. Colin also says good door seals help a lot.

The problem, as I see it is how to achieve a reasonably quiet cabin at cruise speed while not adding a lot of weight. So next I investigated different types of foams which could be bound to the fuselage skin. I feel that the adhered foam will help reduce the oil canning of the fuselage skins and the texture of the foam will help attenuate the noise instead of letting it bounce around inside the cabin.

EAR is a company which makes foams specifically for this purpose. They have several products which look as if they could be effective and come with pressure sensitive adhesive on the back, but as any product made for aircraft use it's not cheap! Here is a run down on what I have found so far.

1 in thick
21 lbs/ft3
.166 lb/ft2
.133/ft2 I bought mine at the building supply store. It comes in sheet form and can be cut to fit between the angles. It's not fire safe.
Fiber Glass
1 in thick
.061 lbs/ft2   This is what Bede provided in the kits.
Back Pack Foam
.275 in Thick
4.2 lb/ft3
.131 lb/ft2
  open cell foam used most for camping is .375 in thick.
EAR E150 PSA 21 lb/ft3   High acoustic absorption, not .5 in thick .083 lb/ft2 1.02/ft2 much for dampening. Fire rated UL 94/vo. PSA is pressure sensitive adhesive.
C3201-25-ALPSA 6 lb/ft3   Masde for aircraft use the Al is .25 thick .226 lb/ft2 5.00. ft2 for the aluminum whick increases the damping.
C3201-25-PSA .145 lb/ft2 3.05/ft2 Same as above but without aluminum skin.
C3201-50-PSA .29 lb/ft2 3.05/ft2 Same as C 3201 25 PSA except 0.5 in thick.

The address for EAR is: 7911 Zionsville Rd, PO Box 68898, Indianapolis, IN 46268 Phone 317-872-1111. EAR is a company that specializes in noise control. They make ear plugs, acoustical foams, energy absorbing foams, damping foams etc. They have many data sheets and a general catalog that is very informative.
(editors note: I tried to locate this company (11/1/2002) and could not. If you know what has become of them please email the info to,Thanks.)

Some of these materials have other advantages/disadvantages. Styrofoam, while being real light, I found difficult to bind to surface of the aluminum skin as it is dissolved by most adhesives. RTV worked somewhat. The Back Pack Foam is not as sensitive. The fiberglass Bede provided in the kit is real light but it will not prevent oil canning of the skin and you still have to add some kind of finish layer over it. I like the foam from EAR and it does install very easily... just cut out with scissors, peel the backing, and stick on. Real nice for the firewall with all the cable feed thrus, but it's heavier and costs more. It looks like there are some good options. Everything is a trade-off. We'll keep you posted as we make our decisions and get some results!      sm

Click on image for larger view


Steve Mahoney had a little problem with his windshield fences that you might want to know about. He had some very nice plexiglass fences that were quite large and had about a 5 inch radius. He noticed right away that they bowed out a lot even at low speeds. He reinforced them by tieing the bottom end to the cowling. As his BD got faster and faster, they bowed more and finally on a speed run, he lost one. It didn't hit anything so everything turned out alright. He has decided to solve the problem for good and now has a curved windshield to install.


If you have ever considered taking your homebuilt out of the country, maybe this will encourage you to get with it and go.

Last April, right while I was as busy as I've ever been with career, house building, airplane wrecking, etc., Steve Mahoney called to say that he, his wife Carol, and their kids were thinking about going to Mexico, and in particular La Paz, Baja. A family friend was going to be there with his sailboat and wanted Steve to crew during some racing.

I warmed right up to the idea as my wife and I had taken our first BD on a trip through Baja and the mainland and really enjoyed it. We talked it over and decided that even if this wasn't the perfect time, at least we really needed to get away! The BD of course was and is without a left landing gear but I do have part interest in a Piper Aztec so at least we had something to fly (although not as classy as a BD-4). My partner in the Aztec said he and his wife would fill the extra seats and buy half the fuel (thank you, thank you).

I talked to Steve Mahoney's parents who happen to live here in Seattle, and they thought the idea was sound. Tom Mahoney flys a Mooney which can't quite keep up with a BD-4 but does a good job.

Another friend who goes down to Mexico about 4 times a year also decided to go with his Cessna 210.

We formed a loose gaggle and headed south for a first stop at Disneyland. I would call it a waste of time but the kids really liked it. By the way Fullerton airport is a real pit!

After minor problems like failed vacuum pumps, leaky front oil seals, suddenly dead battery, high oil consumption, Anaheim traffic, slightly irritated tower personnel, etc., we straggled into Mexicali. By the way do not forget to file a flight plan and make sure they know you are coming. Customs was very easy to deal with and GAS WAS ONLY $.9O PER GALLON. Now I feel much better as I can almost afford 1/2 the gas for an Aztec and we won't even talk about the 2 quarts of oil per hour as Mexican oil is also cheap.

Our first stop was Santa Ynez which is described as "quaint", or I believe someone said "rustic". As we let down, we started to fly sideways as there was a vicious cross-wind blowing. The runway was uphill and aligned perfectly with the wind so we decided to land. The thirty mph plus wind gave us a very slow landing speed but the arroyos off the end of the strip gave us a very rough ride. Steve does not have a lot of time in his taildragger BD-4 and was a little nervous, especially when he was cut off by an Apache and a 170 Cessna. I have never seen anyone taxi a 170 so carefully! What a kite! I had the Aztec down and chocked and quickly ran out to see Steve come down final. He did a great job but should have flown formation with the runway a bit so he didn't have to taxi so far. He said that his legs were shaking so bad that he didn't dare try to walk for a while!

Santa Ynez turned out to be a Rancho, which means that one family lives there and not much else. There was a Cantina and some of us even ordered some food and even liked it. We did some wandering in the surrounding desert as there are some very strange and rare forms of tree and cacti that occur only on the Baja. Finally, the wind got so tiresome that we departed for Loreto for fuel and then to San Ignacio. We were really trying to get to the off-the-track places.

San Ignacio has a very old mission and looks like an oasis as it has thousands of date palm trees. It is definately not a big tourist spot. We stayed in La Posada motel on one of the very back streets of the town. I have never seen "double" beds that were that narrow. We finally put two of them together so that we and our two girls could fit to some degree. Steve's father and mother put one of the spare beds outside on the veranda as there were not enough rooms. We could see stars through the roof in a few spots but it doesn't matter as it never rains. The rooms were very clean except for some blown in dust and the sheets smelled good as they are dried outside. Warm water is piped from the owners house, over vine arbors, through each of about six or seven rooms and finally to ours. Warm water comes on about seven in the morning and stays on for "awhile".

We walked to the mission in the morning sunshine and wondered at the beautifully relaxed lifestyle of the townspeople. The mission is hard to describe. You get the feeling first of shabiness and benign neglect but then the massiveness of the architecture, the coolness of the air, and the quiet make a shiver run up your spine and you stand silent with a lump in your throat. A really most eerie feeling comes over you that makes you want to stay. You suddenly get a feel for the age of this structure when you see that the bell rope has worn through a foot of stone. It is hard to understand how a structure like this came to be in such a harsh, remote part of the world. It is better to only briefly wonder about it and not know the hard historical facts - trust me.

On to La Paz for our longest stay of the trip. We find that the Mexicans do know what a KING SIZED bed really is. The only reason they first show you the rooms with the "double" bed is so that you can discuss it for a while in your bad Spanish, come to an "understanding" and then tip them for their "helpfulness". If all they can do for you is to show you to your room, I guess they feel they haven't done enough for the tip you are sure to give them. I think it makes sense?

We find that happy hour (it is not easy to determine when this occurs) banana daiquires are a definite hazard to dehydrated, hungry pilots. The food is good and the beach hot but relaxing. It is the first place that I've been that you can order what you want and not look at the prices. We even found some Spanish beauties that knew how to "set" and "spike" a volleyball (my daughters were a bit jealous, our wives not at all understanding).

Due to different schedule pressures, we split up on our return home. Steve was having a strange intermittent problem with the starter an his Lyc O-360. Sometimes it would turn over and sometimes not. If the cowl was removed and the starter cable bolt was turned a little, contact would reoccur and away it would go. The laws in Mexico say that you can not work on your own airplane even if you have every US mechanics rating available. It is not that the ratings are not good there but more of a problem with a work permit. It so happens that a lot of the small airstrips in Baja have National Guard soldiers around to aid the USA in slowing the drug traffic. After refueling at a remote airstrip, Steve, under the careful scrutiny of the soldiers, settled his kids and his wife into the BD-4, and hit the starter switch english speaking ears and set about tearing the cowling off. They gathered around and watched but apparently didn't know or care about work permits and didn't get in the way. Steve breathed a huge sigh of relief when the O-360 started and he didn't waste any time in "escaping".

We found that even though the airplanes were about the same speed, trying to "stay together" was difficult. With more airplanes you have a greater chance of something going wrong and it tends to delay everyone. It is nice having the support of other flyers in case of mechanical failures and such but it is better to let each do his own communication and navigation work. We cruised just under 180 mph and did enjoy some air-to-air photography and formation work (we won't talk about "swooping" as Steve's wife Carol seems to have an aversion to it).

All in all (resisting the temptation of a good story), flying homebuilts or any airplane in Mexico is very enjoyable. The airports are excellent, the fuel cheap and of high octane, the people friendly and helpful but with an attractive little bit of "mañana fever". If you are thinking of going you should get one of the Mexico books by Arnold Senterfitt that are advertised in most aviation magazines. Maybe we could get together a BD-4 only trip sometime in the future.        rdm


Paul E. Kauffman
3625 Holiday Village
Traverse City, MI 49684

After the second landing requireing rebuilding of my BD-4 I decided to build a new wing using one of the natural laminar flow airfoils (NLF (1)-0215). Subsequently at Jim Bede's suggestion, I decided to use the Wertmann FX38-153 airfoil. The structure of the wing would utilize PVC foam ribs closely spaced on the original tube spar and 2024-T3 skin bonded with Dexter Hysol 9410 adhesive. Vacuum will be used to hold the skin in place on the structure until the adhesive cures. This procedure has been successfully used by Dick Schreder to make the wings of his HP sailplanes. It produces an extremely rigid wing with smooth surfaces which maximize laminar flow. Other interesting features of the new wing are:

  1. Utilization of the spar and a portion of the wing for the fuel tank.
  2. A wing tip to contain the filler cap, a sump and quick drain tank vent, strobe and navigation lights, pitot tube, and perhaps antennas.

This arrangement leaves the wing surface undisturbed by filler caps which induce turbulent flow thus increasing drag. The filler cap inside the wing tip will be higher than the top surface of the wing allowing filling the tanks to the top. The sump in the tip reaches below the lower wing surface providing a reserve of fuel in the event of exhaustion of fuel in the tanks. A separate pick-up to the sump is required. Navigation wires and pitot tubing will occupy a separate conduit located along the ceiling of the spar. The spar will also contain baffles with flap valves to keep the fuel inboard during any manuever tending to sling it outboard. To reduce the cost, standard four foot sheets of aluminum will be butt joined with two inch doublers located between ribs. Two and a half four-foot sheets will cover each regular length wing. About seven feet are required to wrap the wing with the ends bonded to a channel which serves as the rear spar supporting the flaps and ailerons. Three sheets will cover a long wing half. In either case, two doublers will be required.

Anyone interested in further details and coordinates of the FX38-153 airfoil may write me for more information with a self addressed, stamped envelope. If all goes well I am planning to have my BD-4 with the new wing at Oshkosh next August for show and tell.      pek


Ves Irvine, 7949 Rhodes Ave, North Hollywood, CA 91605, PH 818-982-9920 has blueprints with instruction booklet/materials booklet, Main spar, main gear legs, gear mounting hardware, stainless steel for firewall. Sell as package for $500.

Joseph Olt, RT 1, Box 16, Cotesfield, N8 68829, is interested in buying a BD that is unfinished. He is interested in using a Buick/Olds VB of which he has several.

BD-4 plans and spiral "how to". 707-463-0467 late nights.

Martin Steele, 8A Brooklyn Dr, Blenheim, New Zealand, needs a set of spars.

Jerry Grant, RT 2, Box 528, Rolling Fork, MS 89159 PH 601-873-2841 or 6708 (home), is in need of parts for the BD-4 wing system.

Howard Walrath, 6335 Douglas St, Plano, TX 75075 PH 214-248-4104, has a very good set of wing buckets that were hand selected and have flap valves installed in the fuel bays using .016 AL and a short piece of hinge. He also has a standard nose gear with all design improvements installed and has the heavy wall design. It has all welds X-rayed, nose wheel and tire are new and all 5 friction springs are installed. Nose wheel and strut are faired in.

Gary Cook, 6713 Waxwing Way, Sacramento, CA 95842 PH 916-344-8318, has a BD-4 for sale. The fuselage is complete, but the skin is off, the panel is in, controls are done but out for cleanup, tail is complete, wing is done but is made of the older panels, IFR instruments are included, seats are not done, it is on the gear, includes an engine mount for an O-320 and has a cowling with cowl flaps. He is asking $5000.


Thanks to all those that sent letters. I will talk about the different subjects in the next newsletters. I keep a file of them and don't put them in the "done" basket until I've included them in a newletter. Some of the interesting things coming up include Ray Wards new longer wings, Bill Breau's airplane, leaky fuel tanks, ways to "filter" your fuel, Boeing airplane front seats, fiberglass doors, a new source and prices for BD parts, and header tanks.


We are doing fine on the dues. If you have an "@" symbol in front of your name, you still have a couple of letters coming.