BD-4 NEWSLETTER #25 - February, 1997
Roger D. Mellema
17605 SE 288 PI.
Kent, WA 98042, Ph: 206-631-5324
rmellema@who.net (or: rmellema@boeing.com)
Homepage: http://www.halcyon.com/www2/rmellema/BDindex.html

The editor of this newsletter cannot verify that the information contained herein is accurate. This newsletter is only a clearing house for the ideas and opinions sent in by various BD-4 builders/owners. Treat this information as if you overheard it during a "hangar flying" session at your local airport. rdm

Dues:
The number before your name on the address label tells you how many issues you still have coming. The cost per issue is $2.50.

Greetings!
Spring is almost here and it is time to think seriously about what it will take to get to Oshkosh with your BD-4! It is assumed that once your homebuilt is flying, all you have to do is a little maintenance and an overhaul once in a great while. Not so at my hangar-there just always seems to be something else that would be nice to experiment with!

Of course, along with this experimenting we do learn new skills, get better fuel economy, go faster, fly more accurately, and in general make a better airplane. Maybe we wouldn't be happy if all we had to do was to spin flying yarns to the local airport denizens.

Work on 76VR is continuing - it is probably destined to never be finished again (if only I were making some money doing this!).

30 Year BD-4 Celebration:
I know, I know, it is a little early yet. I just wanted to get you moving. We really have to have a good get together for 'our'' 30th. I started this paragraph by saying that we 'had to make a good showing', but what do we care what others think about our choice of airplanes. It is important that we get together and revel in our good fortune to be smart /lucky enough to have discovered such a great hobby and such a great airplane!

Get busy! Maybe we should have our celebration someplace other than Oshkosh?

 
And we thought we had seen everything! Ray Ward has done it again (or is trying to do it)! This started out as a standard BD-e. Ray is modifying it to do things even Bede never expected of the '8. If the gear looks a little lanky - it is. In this stance, the top of the bulkhead just behind the cabin is a full 6 feet high! That is what happens when you want to build something to beat the Sukhois.

Ray is working on a super engine, PSRU, and prop to power this thing. It will be the first BD-8 to fly with the 'differential stabilator' hooked up. Yes, it takes over the job of the ailerons when you are going vertical. The prop blast over the stab should really keep this thing wound up!

Can you imagine the 3-point visibility? Of course, it is so narrow you can just look around the engine right? You surely can just bring the tail up the moment you cob the engine.

Now for those of you interested in reducing the weight of your BD-4s, you should see the holes in the wing spars of this airplane. Hey, they did it on the BD-5!

The BD-8 was made to fly with a Lycoming 10-360 and a Hartzel constant speed. I believe there are two of them flying.

Internet changes:
I hope many of you are getting started on the Internet. It is a fabulous resource and I am getting more BD-4 builder email addresses by the day. I will list all of the known addresses in the next newsletter. Please make a note of the new homepage address given above (the server changed the addressing scheme). Please let me know how I can improve the web site so that it is easier for you to use. I will be adding all of the newsletters as time permits.

You will also notice the change of email address. This is a new 'permanent' email address that will shunt my mail to whichever server I am using at the moment (halcyon). The "rmellema@halcyon.com" will still work. If you want to sign up for a permanent email address contact: http://www.bigfoot.com or http://www.iname.com

Auto Conversion Ignition Options:
Robert Bollinger is still working on his 3.8 L Ford V-6 conversion for the BD-4. He has discovered that the MSD crank trigger system works well with the Ford ignition system.

You can also use the standard High Energy Ignition direct replacement module built by MSD that will allow spark advance adjustments from the cockpit. The unit is an MSD #8782 and sell for $123.99.

Dynamic Balancing:
Dynamic Solutions Systems, Inc. (619-744-0187) are producing a fantastic propeller/ engine/ rotor vibration analysis system. I talked with them for a very long time at Oshkosh and would like to purchase a system to help find vibration problems on homebuilt airplanes. Besides the obvious propeller balance problems it can be used to find the resonant frequency of the engine and accessory mounts. If these frequencies are exact multiples of engine phis that are commonly used, the result will be many broken parts.

The certified engine/propeller combinations have mostly been proven over the years but the auto engines with their Propeller Speed Reduction Units and experimental propellers bring up a whole new set of problems.

New Exhaust - more power?
The exhaust pipes on my Ford V-6 were a quick guess and made out of mild steel - after a few hours they sported many repair welds. They were each a solid weldment and 'cantilevered' from the aluminum heads. The exhaust bolts used by Ford are 1.25" long so that they don't easily pull out of the aluminum but it is pushing things a bit to expect them to support cantilevered exhaust that each weigh 7 lbs and are 2+ feet long (although they did lust that for 140 hours). Other builders suggested 'snubbing' any 'vibrations' by loosely tying the outlet end of the pipe to the firewall. This would make sense if a resonance were to be triggered in the pipeby the engine movement. I don't believe this happens as the pipes are very rigid and the resonant frequency would be high enough that the engine wouldn't excite it.

The only way to isolate the weight of the pipe (and muffler) from the head is to use swivel joints. These can be obtained from Ken Brock (gyrocopters). They are made from 321 stainless and are priced right (-$15). My first plan was to have these 'isolators' between each cylinder and one just after the three pipes join. As it turned out, there was not enough room to put them between cylinders as I changed the way the exhausts are built. The early exhaust ran for 18" before being combined into a single outlet. Calculations show that the pressure wave of one cylinder firing is long gone before the next one occurs - therefore it makes sense to eliminate the extra pipe. The three ports on each side of the engine are now collected together before a ball-joint is installed to isolate the 'tailpipe' and 'muttle'.

During the Arlington Fly-in I talked a long time with Mike Hirshfield (604.463.9746) who owns a V-6 STOL on amphibious floats. It is hard to believe anyone could doubt the power potential of the V-6 when you see this 'little' engine powering around so much drag. Mike said that he can get off of lakes at 5000' altitude, at 80° F with a full load! According to Mike, part of his success is attributable to the SuperTrapp muffler. When he first ran his 3.8 L V-6, he was getting under 200 hp. By combining the exhaust from both sides of the engine and tuning the single SuperTrapp for maximum power at -4600 rpm, he ended up with 230 hp. With a draggy airplane (the speed difference between liftoff and cruise is small), and the need to get off the water at high altitudes, he can use a prop that almost turns redline static.

The SuperTrapp is unique in that you can vary the back-pressure by changing the number of 'disks'. I know, you don't really want back-pressure!! It turns out that varying the back-pressure moves the torque curve around. With a fixed pitch prop it is helpful to move the peak torque down so that take-off performance is improved.

I am now using 2 small SuperTrapps (20" long, 3.5" diameter) that quiet the exhaust substantially and seem to work well. The exhaust/SuperTrapp system is not 'tuned' yet but I did fly for 40 minutes and found the take-off power to be somewhat improved.

I discovered that you can swap the exhaust manifolds left side-to-right side if you build them 'flowing aft' and later discover that you really need them to 'flow forward' so that the muffler will tit!


  • Alan Harpley Janney Fors, Hawes, North Yorkshire, England, DLB 3LY, Ph: 0/969 667475) has need of an engine mount for an 0320-A2B Lycoming. This engine needs the earlier "straight" mount (include the engine bolts and the rubber mounts). He also would like to buy a propeller of some type (74" diameter, 64" pitch).
  • Ron Reynolds (100 Road 11, Worland, WY 82401, Ph: 307-347-3096) would like to buy BD kit in any stage of construction. He would like to stretch the fuselage, use a long wing, and auto power.
  • Bob Van Zant (24017 61 st St. Paddock Lake, W I 53168, Ph: 414-843-4044) is looking for a BD-4 project. He would prefer one that is not too far along.
  • Jeff Bertuleit (Props Inc. 503-265-3032) has a propeller for sale. It is multilaminated maple and is 70" long. It is good for about 180 hp.
  • George Kruchka (916-842-2557) is looking for wheelpants for his BD-4. He has 600 x 6 tires.
  • Cordon Marrow (42772 Almond Grove, Murrieta, CA 92562, Ph: 909-677-5868) is selling his BD-4. It is a taildragger with zero hours airframe and engine. The engine is a SVX 3.3L Subaru flat 6 cylinder (rated at 220 hp I believe)
  • Charles Olson (401 2nd St. S.E., Watertown, SD 57201-4332, Ph: 605-886-8382) will build your gussets for you. He has all of the equipment and can make it a lot easier for you.
  • Lary Seibold (10621 32 no Ave. SW, Seattle, WA 98146 Ph: 206.248.1133) has a well-built nosegear with a Murphy fork and wheel. The wheel used is 5.00 x 5 and should have been a 5.00 x 4. Otherwise it is nicely built. Make offer.
  • Willard C. Collins (238 Fairville Rd., Chadds Ford, PA 19317 Ph: 610.388.2393) has an engine mount that fits an 0-360 Lyc and a used cowling.
  • D. G. Davis (43200 70 th St. West, Quartz Hill, CA 93536 Ph: 805.722.0693) has an Aluminum block GM 215 cu in engine for sale. It is overhauled, ready for reduction gear drive but needs a fuel delivery system and exhaust. He also has 3 AL blocks, 5 sets of heads, 1 set of 300 cu in AL heads, two 300 cranks, AL intake manifold and steel. Also has forged rods, ultra dyne cam and standard cam 263 cu in (240 to 250 hp).

A Better Nosegear system:
Keith Anthony has been fighting shimmy in the BD-4 nosewheel and can't seem to conquer it. He is considering changing not only the nosewheel type and size, but also the way it is connected to the fuselage. He has been looking at the RV-6 method in which the entire nosewheel system is a part of the engine mount. This really makes sense as, the weight that the nosewheel supports, is the engine.

Metal Wings: (information from Fred Hinsch)
Many people are now building metal wings for their BD-4s. There is no ready source of information for doing this so I have decided to include the basic technique in the newsletter. Fred Hinsch built a metal wing for his BD-4 and has supplied the following methods, weights, and techniques.

The specifics are:

Total wing span = 29', wing area 116 square feet

Weights: lbs
  • Basic structure (spar, ribs, rear spar)
  • Skin #1
  • Skin #2 16.5
  • Skin #3 5.5
  • Rivets 1.5
  • Flap 6.0
  • Aileron + torque tube 6.0
  • Balance weight (aileron) 1.5
  • Wing tips 5.0
50.5
15.0
16.5
5.5
1.5
6.0
6.0
1.5
5.0
Total for each wing 107.5



The ribs must be adjusted to fit the skin size you are using. It is nice to find 5' wide aluminum for standard length wings but most of us have to deal with 4' skins. The skin is normally wrapped around the leading edge so that there are no seams from trailing edge to trailing edge. This means that 3, 4' wide sheets will just do the trick for the long wing - the only problem being that of avoiding a butt-seam in the fuel cell area. If you have the first 10" empty (per Bede plans), you have <38" to put fuel in before the seam. The BD-4 hold about 7 gallons per 10" bay. Bede recommended 3 bays (30") on each side for a total of 40 gallons. I find this a bit short so the -37" should be fine. The first bay (empty) can also be shortened a bit if you want more fuel. An empty bay of less than 6" would suffice.

The solid rivets specified above are light, cheap, and effective (they actually 'set' the countersink better). We have discovered that driven rivets don't seem to work in the fuel tank area. They can be dipped in ProSeal before driving but the action of driving them, hammers all of the sealant out, and a leak results. The blind (pop) rivet seems to work much better as they are set by one nice smooth 'pull'.

Pop rivets can be used on the entire wing. They are easy but are a bit more expensive than the driven rivets. In the fuel tank area be sure you use the pop rivets with the closed end. There is a much smaller chance of leaks with these rivets.
Wing ribs available from: Lang Aviation, 912 Summey, Wichita, KS 67217, Ph: 316.522.1697
or: A&E Aircraft Services, 2803 126th Ave S.E., Bellevue, WA98005, Ph: 206.746.3920


I have been purchasing parts for Carlos Serodio who lives in Mozambique. He wants to use an No Prop on his 10-360 and would like to be sure the prop stays together with the 'beat & pound' of the flat four. No has had some trouble with this but now has an improved prop that will work.

Carlos heard about this device and asked me to order it for him. It costs $375 and weighs 12 lbs. The center flange is only for centering. The 'ring' is held onto the Lycoming flywheel with 12 bolts around the perimeter as can be seen in the picture on the right.

"A steel ring floating in silicone fluid inside an aluminum case. Weighs 12 lbs., attaches to the forward part of the starter ring on Lycoming engines using prop extensions. Provides increase of 75 to 100 rpm. Dampens engine tiring pulses, gives inertia to engine rotations and dampens out 30 to 40 % of harmonic and other engine frequency vibrations:"

Mark Landoll's Electrical Service, 2112 SW 76 St., Oklahoma City, OK 73159 Ph: 405.685.0239

SuperCharged Ford Information:
Two really great testimonials for the SuperCharged 3.8 L Thunderbird engine have recently come to light.

The first is from William O. Singer in Hale, MO. William and his son both have Thunderbird SuperCoupes. One of them recently blew a head gasket (at close to 200,000 hard miles). The subsequent partial overhaul showed unbelievably low wear. The ridge normally found at the top of the cylinder bore was non-existent and it was decided that a simple replacement of the head gasket and torqueing to the new Ford specifications was all that was needed.

The second occurrence was here in Seattle. An EAA acquaintance has a large auto repair facility and experienced the same situation on an engine with 160,000 miles on it. This engine was torn down all the way and everything measured. The bore taper was about 0.0007 inches! The pistons were pushed out the top of the bores without doing any'ridge reaming'. New rings were installed and the bore was lightly honed. The crankshaft was very lightly burnished and new bearings installed (original Ford quality, of course). The roller lifters and cam were in such perfect condition that they were not touched.

Ford uses rings that have a layer of molybdenum on the wear surfaces which really reduces ring and cylinder wear.

Steve Cralgle, Tim McGinnis, and John Steere continue to work on getting their SC engines installed and their airplanes finished. I have not heard of any of the engines as being ready to run yet.

John Steere sent pictures of his header tank installation. One of the things that have to be worked out on the fuel injected auto engines is the need for high pressure fuel pumps. John has worked out a nice header tank that holds two high pressure pumps. It is fitted with a float switch so he knows when it is not being fed from the wing tanks. A water sensor, a vent to BOTH of the wing tanks, and an input from the fuel rall for the overflow are also included. It looks like it has all the requisite equipment for good fuel feed.

Wing renewal (Ardis Almond):
I thought you might like this information on this work on my BD-4, Pat's Patience, N71 AG, since it might apply to others with the same problem.

I finished my plane in 1979, I had the white wing panels that were of low quality. At the time I was building my wings, builders were recommending that the fuel tank area be overlaid with dynel cloth and polyester resin to help the leak problem most builders were experiencing.

I used this method in my construction and still had leak problems from the beginning. Over the years, I worked on the wings several times. I made many surface patches with ProSeal. I also cut inspection holes in the wings and tried to seal the problems from the inside. It continually got worse. I found that the dynel started delaminating and any pinhole leak traveled between layers until it found a way out. These pockets caused further delamination. I finally had to bite the bullet and do a permanent job.

In February, I brought the wings into my shop. I removed the flap/aileron assembly. I peeled, scraped, and sanded off the dynel layer. This got me back to the original panel surface. Isophtalic polyester resin (fuel tank resin) was used to patch any abraded spots on the panels. ProSeal type fuel tank epoxy was used to seal any suspected joint leaks.

The fuel tank area panels were heavily sanded. Then a very thin film of ProSeal was spread over the surface. While this was wet, a single piece of 6 ounce fiberglass cloth was wrapped completely around the wing and overlapped on the trailing edge. The glass cloth was pushed into the ProSeal by a small roller until it was smooth and the ProSeal went into the weave from the back side. This was allowed to cure.

The Isophtalic resin was then applied to this glass cloth. Traditional composite methods of micro slurry buildup and sanding was used to get a smooth finish. Featherfill was used for final finishing and then the entire wing was repainted.
The plane was put back into service in mid-June. At this time (September) I have had no leaks or blisters in the paint. I feel this method will work because the ProSeal will seal the tank and the cloth will keep the ProSeal intact, as well as strengthening the wing panels.

I will be glad to discuss my method with anyone that is interested.

Inspections Before First Flight:
We all know the importance of good inspections before first flight and we know it helps to have a couple different people go through the 'check list'. There is a check list in the Bede plans (at the back of the pilots handbook and on page 165 of How To Build Your Own Airplane) but it gives only general topics (not which way what should move, for instance).

A recent incident has reminded us again that "Murphy" will always be with us. Question: how would you check to see if your (anti-) servo trim was working correctly (not wired backward)? It takes a little bit of mental gymnastics to get to the answer so maybe a checklist is needed that gives more explicit directions.

In the incident in question, the first flight went fine until trim was needed to ease the stick pressure. The trim wheel was turned (grunt, ugh) but the pressure was not relieved on the stick. The decision was made to land and then sort out the problem. This was easily accomplished. Apparently, it was not noticed that the trim caused greater stick pressure or it would have been recognized that it was just wired backwards.

It is the small things that seem to pervade our minds and keep us from trouble shooting correctly. In this case, the builder was already concerned about the CG position. This expectation of trouble with CG pushed out all thought of other things that could make it seem that there was a CG problem. This prevented him from experimenting with rolling the trim the other way.

By the way, if you pull the stick back (the anti-servo will come up), and then roll-in "up" trim (move the top of wheel back), the anti-servo tab should go back down some (at least that is how mine worked just now!).

Thoughts on Iron Mike
(Autopilots):
How good are you at flying with your knees and your peripheral vision? Most pilots have been doing that for years while they scrutinize their maps for whatever (just wait until you need bifocals!). Every time you think you have found the answer, the airplane gets out of whack enough that you have to look up and get things back under control. Don't even blame it on not having the proper dihedral (us BD guys are sensitive about that)!

Ever been flying at the higher altitudes and find that the heading is 30° off every time you look at it (you could have sworn that you just looked!)?

It is so much nicer if the airplane remains stable while you perform your map functions. A decent copilot is the best solution as he can fly an scan for threatening traffic. This doesn't always work as most copilots are trying to help you look at the map (they always think they can find 'it' better). What I am trying to get at is the (almost) 'need' for an autopilot.

How well does the autopilot meld with the BD-4? A lot of BD-4s have sported autopilots at one time or another. Remember the NASA generated system that used an enclosed air stream, fly-speck varistors and the 'water-hose-effect'? This was commonly known as a 'Fluidic Inertial Rate Sensor'. It generally used clothes dryer flex hose and a vacuum source for actuation of the control surfaces rather than the more common servo motor or the model airplane servo moving a trim tab.

You probably never heard of the 'Electrostatic Autopilot'. This one used the earth's electro-potential field at the wing tips to determine which was higher'. I had one of these working in the lab but never got it installed. A method of ionizing the air surrounding the wingtip probes was needed so that static build-up would be prevented. This required the use of radioactive alpha sources (I always wanted to go to Oshkosh with "Radioactive Hazard" stickers on my wingtips!).

The most common of the autopilots are those that use a gyroscope to measure motion (or attitude). The error signal is then used to drive a servo-motor that in turn drives the control surfaces. There are also lots of things to worry about like over-shoot, loop gain, loop bandwidth, and several others that we will ignore for now.

More of a worry to builders is: required BD-4 modifications to make an autopilot work.

Use of Servo-Motors

The easiest method is probably moving the control surfaces by brute force. This requires a Servomotor that can generate a substantial force. One large disadvantage of full force servo-motors is their WEIGHT.

Use of Trim-Tabs

Trim-tabs must be added to the aft side of the control surfaces or they must be built into a 'cutout' in the control surface. Tabs mounted on the aft edge will have more moment arm and therefore can be smaller. Trim-tabs almost always require the Radio Control servo-motor to be mounted inside the control surface which adds to the weight required to be counter-balanced in airplanes that require statically balance surfaces.

Mounting The System

An autopilot from S-TEC arrived unannounced at my door one day with a request that it be installed in a BD-4, tested, and demonstrated to whomever wanted to experience it. That was a couple of years ago and it now is finally installed and working. A major installation decision was which control surface it should control. Those of you flying BD-4s know that during cruise the best approach to keeping wings level is to use just the rudder. It works well to lust use your big toes to push gently on the lower part of the rudder pedals. The ailerons, when used by themselves, make the airplane sway around to a greater extent due to the adverse yaw (see NIL #22, page 1, & NIL #23, page 2).

The initial installation of the 1 axis autopilot (wing leveler) was made with the high power servo connected to the aileron system. It was connected just below the pilot's left knee and was connected into the solid push-pull aileron tubes (as modified according to NL #17, page 22).

Flight test shows that the adverse yaw is virtually unnoticeable during autopilot operation. The S-TEC autopilot is well damped and works well even in the VOR mode. The next step is to swap out the current directional gyro for one that will drive the autopilot. It is nice to use the heading bug on the DG to drive the autopilot rather than the VOR as the DG is'always available' and can be set to any direction. The autopilot does already have a 'wings level' mode that is driven by the output from the Turn & Bank but it will drift enough that it is better to use a DG.

A desired upgrade is to use the GPS to drive the autopilot. You will notice that none of the handheld units have a standard aircraft autopilot interface. They all have the NMEA (National Maritime Electronics Association) 4800 baud serial RS-232 digital interface rather than the simple +/- voltage level (left / right) signal common in aircraft. There is a source for a converter but it is priced at around $200. That is a fair percentage of the cost of the GPS. It is cheaper than my time to design and build a similar system but it is hard to put out the money. It is cheaper than buying a new DG with the autopilot interfacel

Most panel mount GPS units alreadv have the standard aircraft 'VOR' interface.  


StaggerBede
And we thought we had seen everything! The BD-4 concept is really an airplane for all men (and engine, and wing configurations).

I recently received a letter from Neale Eyler (2114 North Stretford, Wichita, KS 67212, PH: 316.941.7488) in which he describes his 'fondest desire'. And I quote:

"I hope you are sitting down. I have an innocent question. Just suppose some fool decided to put a bottom wing staggered say starting at sta 50 putting the center bottom spar centerline at say sta 65. Probably someone building their own wings, so aluminum skins on standard spars and the top wings with ailerons and the bottom wings with flaps. The potential for more fuel also becomes available.

Upon reading specs of the famous staggerwing Beech, a 3/4 scale model has dimensions remarkably close to the BD-4 as modified above. The Staggerwing has remarkable speed, stability, load carrying, and slow speed ability (just not sure on STOL).

Also a bottom spar might help provide support for the conventional gear legs (and almost starts one thinking of retractable).

Anyway, I don't have a clue what to do with the tail feathers in this scenario - try to scale down staggenwings, or would standard BD-4 do? You have hinted at having some engineering buds nutty enough to pencil some of this out. What do you think?"
3/4 Stagerwing scale: wing span = 24 feet
length = 20 feet
height = 6 feet
cabin width = 42 inches
1250 lbs empty (Ed., a dream)
2400 lbs gross weight
170 hp - 170 mph


Now Neale is not the first to think of a BD-4 biplane (there is one newsletter member who is working on one - I just forgot who - sorry) but the loose connection to the Beech Staggenwing is clever. This might be the answer for those of you who want a lower stalling speed! Of course, you will also be the slowest BD-4 around.

The Beech Stagger did get great speed but at the expense of a lot of horsepower (and fuel consumption).

Where to go from here is the question.

  1. You will immediately pick up 200+ lbs of added vehicle weight (not including the cute inter-wing strut). The lower wing spar really doesn't have to be equal in strength to the top wing (we still only have to lift the same weight) and we would get some 'spar strength relief' as the lift produced by the inner part of the lower wing will be put into the lower cabin area (and not have to be carried by the upper spar). This does mean that the 'cute' inter-wing strut has to be functional. It is probably best to just make the lower spar equal to the upper.
  2. The lift will not be doubled as there is substantial interference flow problems with wings in close proximity however, there will be substantial increased litt. Our short wing chord will be a benefit in a bi-plane configuration. We could shorten the lower wing to get rid of some of the excess lift (and drag).
  3. The center of lift will move forward but I am not sure quite where. This means that things have to be moved around to get the balance back within reason. The passengers are not a good option unless the firewall gets moved (and it might have to). The engine can be moved forward for improved access to the rear of the engine.
  4. Increased lift says increased wing pitching moment. This means we have to revisit the tail volume - but if the center of lift and center of gravity move forward, the tailboom effectively becomes longer and therefore already has a better mechanical advantage. The tail volume might be fine as it is (except for that ugly fixed tailwheel).
  5. The main gear would have to be moved forward to keep up with the Center of Lift / CG movement.
  6. This airplane just wouldn't look right with a fixed main gear - although I believe the early Staggewings were fixed. The lower spar could be used for the main gear carry-through, but where would you tuck the wheels away?

    BD-4 owner David Dotson immediately decided that the lower wing should be below the fuselage (ala Paul Kauffman and his main gear box) to get more distance between the wings. This would give a nice hollow belly (about 7 Inches deep) which would allow the wheels to tuck below the front seats. The rear seat passengers could sit more upright as their feet could be 'down in the belly'.

    This dropped belly modification adds more drag due to the increased wetted area and also the weight of the structure - not to speak of matching the tail boom to it (might require moving the tailboom back 20").
  7. It might be a good thing that we need more weight forward as we might desire a larger engine to pull all of that drag around. Now that Russian radial engine comes to mind. It would really make the airplane resemble the Staggenving. Or course, the gear might have to be lengthened some to get the prop clearance necessary.


I don't know - sounds do-able to me - but of course, We Are Experimenters!! It kind of makes the
heart pound and the blood race!
It may be time to put a basic configuration into the EGADS program and see what it comes up with. I do
plan to work at it a little but will let Eyler and Dotson do the building.

You can't go home again - or can you?
I received a letter from Joe Thalman who now owns his father's BD-4 and is slowly refurbishing it. He is putting on metal wings and will install a Lycoming 10-360 to replace the 165 Franklin. Joe soloed in N14BD and now flies F-16 Fighting Falcons and actually got to fly one to the '95 Oshkosh. I guess sometimes dreams can come true! Can you imagine getting to fly one of those (with free fuel) and then coming home to play with your BD-4? I expect there are a few fewer rules to adhere to with the BD?

Welcome to our group, Joe! It is nice to hear of 'kept in the family' BD-4s.

Paper Airplane BD-4?
John Brecher's BD-4 has found a new home. Ken Blackburn has purchased N186JB and is 'allowing' John some time in it if he helps with the maintenance (kind of like having your cake and eating it tool).

The 'Paper Airplane' comment in the title is due to Ken's major interest in life - that of designing paper airplanes, flying them (setting world records), and writing books about them so we can have fun too. You might visit his web site at: http://www.geocities.com/CapeCanaveral/1817/



LightSpeed Ignition:
Carlos Serodio also had me order an ignition setup from Klaus Savior. Steve Mahoney has a slightly earlier version of this system and recommends it as the best thing since sliced bread. He was miffed at all the time he spent fairing in his airplane to get a couple of more mph. He installed this system and picked up a full 5 mph (and probably with better fuel economy). Steve said that there was a noticeable difference in climb capability. He also idles verrrry smoothly.

The price for this system is just under $1000.
Light Speed Ignition, PO Box 549, Santa Paula, CA 93061

Dream Aircraft
(616.454.7747):
Scott DeGaynor and John Gill are rapidly getting into the airplane business. They now have wing spars and center sections in inventory. They have several spar sets yet available. They have been busy making the difficult parts and making changes where necessary. Many of the parts are interchangeable with the BD-4. They have produced and shipped several of the modified parts such as longer side channels and longer spars. The following list of products will get anyone started with building or rebuilding a BD-4. Contact Dream Aircraft for availability and pricing.

Available now:
10 foot spars Super Tube set (1 cabin spar and 2, 10' wing spars)
12 foot spars Super Tube set (1 cabin spar and 2, 12' wing spars)
88 inch cabin spar Super Tube center section
62.25 inch side channels
80 inch side channels
front door posts
rear door posts
landing gear box with steel legs
landign gear box with aluminum legs
Available soon:
all steel parts pre-welded
aluminum wing anels (complete with ribs)
aluminum angles

For Sale: a complete BD-4 kit. Complete kit, on the gear, with control systems, and fiberglass panel-ribs (not assembled). Scott, Ph: 616.454.7747