BD-5 - Why is it so engrained in our psyches?

[pylon500]

With my old employment, the pilots who were hardest to train were the ones that were military trained. The military did a great job of job specific training. That’s why they get to fly a T-38 at 500 hours or some such low number. It’s their job. 500 hrs GA, buying fuel, might be Bonanza grade for the regular pilot. Out in the wild, one has to push yourself past the trainers. No one will do it for you. The issue with many military pilots is they think they got it because they are “ downgrading “ with GA.

We pretty much had the some problem here in Australia when ultralights first appeared.
Back in the beginning if you wanted an ultralight, you had to build it, and they were being built by, aeromodellers, hang glider pilots, sailplane pilots and GA pilots.
They then went out and tried to teach themselves how to fly these lightweight, underpowered and suspect design and control system aircraft, and do you know who killed themselves the most?
GA pilots!
These were the guys that knew it all so they just jumped in and took off, not always coming back. All the other guys could see how different this was from what they normally flew, so felt their way carefully.
That all changed (for the worse) once the 'off the rack' ultralights became available, and non flyers with money bought them, and dig holes around the countryside.
Anyway, back to the BD-5...

 

[Tom DM]

Lots depends on the pilot’s experience. My friend, a Navy test pilot, had never flown anything as sensitive as the BD-5. His first, and only, takeoff led to a crash due to PIO. That would not have been an issue for a pilot with time in many homebuilts.

Another friend / coworker / father of a classmate was a navy jet pilot with combat experience in Korea. I convinced him not to build a BD-5. He built a Lancair 320, but was not really experienced with the big airbrake (constant speed propeller) out front. He got slow on his first final approach, got into a high sink rate, hit the ground and burned to death. For flying time to be an asset, it needs to be relevant to the aircraft.

What I may deem to be easy to fly, others may have a problem with. What they find easy may be an impossible challenge for me.


BJC

+1

Lots depends upon experience for sure (any F16-jockey will ride a C150), yet even more on respect and an open mind.

That one is a master in a specific domain, does not automatically transfers the "mastery" to an other domain. Withnessed such people, which despite ample and straightforward warnings, losing fortunes and far beyond (even the accident report (5 deaths) mentionning "master in his trade" explicitly).

A real "master" keeps his mind open, will evaluate advice even if coming from a supposed no-one. I consider it good fortune to have met such a white raven who prooved beyond doubt that he was a billionnaire on merit.

 

[AndyCapp]

@AndyCapp What are you running for radiator / where? Looks like it's plumbed down and behind?

The radiator sits in the belly behind the pilot and is fed cool air via a scoop and a electrical fan is also used on hot days. The radiator is from a Honda 500 Vtwin turbo.

 

[AndyCapp]

Turning the 582 at 7200rpm must be giving you close to 70hp, although the Rotax manuals suggest your power is starting to drop off even before the rated 6800rpm redline. Your inlet and exhaust system look pretty standard, so I'm surprised it's breathing so well.
So, many other BD-5's in SA?

Only one in SA..

 

[George Ackerson]

Hello,
I'm 100% new to this forum but have several boxes of BD-5 parts available (bought complete A/C years ago -but the fuselage and wings got lifted from me when it was in storage (probably sold for the Aluminum) - most all components are still in original wrap and boxes; with a good canopy and floor-pan.
I think these may well serve a builder, or someone that needs spares.
I suppose if you are interested you can contact me here; though I don't know the forum's restrictions on giving out phone / email addresses.
Thanks - George in Central Montana
.

 

[David Moxley]

Oh I know about the BD-5 , I have Owned 6 or 7 different ones ,I’ve done a bunch of building on them . There is not a reliable motor for them , they’re super cool but in reality the ones that have flown I’ve always had problems unless you go with a jet and that’s questionable ? they’re basically a death trap ! If you want to be the first one to send the accident then go for it ! I have seen several of them built in the past and most of those people had problems and have passed away from flying them. The only one that was somewhat successful was Keith Henshaw. they are still a fascinating airplane. . The last five kits I had from in the box, to on the gear, I sold , I got over it , there are better designs out there than Jim Bede myth ! I don’t even know why you guys keep talking about it? I’m done ! They will kill you !

 

[Tom DM]

Oh I know about the Owned 6 or 7 different ones ,I’ve done a bunch of building on them . There is not a reliable motor for them they’re super cool but in reality the ones that have flown I’ve always had problems unless you go with a jacked and that’s questionable they’re basically a death trap I have seen several of them built in the past and most of those people had problems and have passed away from flying them they are still a fascinating airplane. . The last five kids I had from in the box to on the gear, I sold all of it , got over it , there are better designs out there than Jim Bede myth of displaying that everybody get on for next to nothing. I don’t even know why you guys keep talking about it ? I’m done ! They will kill you !

All kinds of people: some are silk, some are steel, some are satin, some are leather (B. Joel)

Did you sell the "last five kids" after you knew they were deathtraps?

 

[David Moxley]

All kinds of people: some are silk, some are steel, some are satin, some are leather (B. Joel)

Did you sell the "last five kids" after you knew they were deathtraps?

Of course I did Tom, sell the kits , not my kids, lol
2 where on the gear The others were in various stages of completion , they went to Finland .

 

[Martti Mattila]

About the Finland and BD-5 one was flying here in eighties, first with Rotax two stroke than with BMW boxer and again with Rotax. Takin of with low fuel engine quit and turning back to runway called impossible turn ended fatal. I saw one kit for sale here arrived in crushed condition don´t know what has happened to it. "If you wanna be the first on accident site." that was a hilarious.

 

[Tinbuzzard]

A few more general comments on the building of the BD-5, not on just its flying qualities. It's a small, lightweight airplane and in my opinion, sensitive to build quality. Weight reduction was paramount during the 5's development, so there are a lot of parts that are structurally adequate in the airframe and control system, IF built and installed properly. That means there's not much margin for overload or builder error; it is somewhat fragile to rough handling. Good workmanship is important. For example, the pitch control system is cable operated in the original design and those can easily stretch or pulley brackets deform, thus it loosens up and needs to be periodically readjusted. I completely redesigned that system in mine to full pushrod and torque tube control which provided far more positive control. I also replaced various welded, thin sheet crank arms in the control systems with custom machined parts to reduce deflection under load. Particularly for the flaps where I upgraded the stock bolts and pins at their roots that visibly deflected when I applied loads by hand. My tail section also has a few added small doublers where the stab pivots and VS attach, plus the aft end of the prop shaft. Several of these are known published aftermarket mods, and in my opinion are mandatory! At least in my plane, this has worked very well. The casting that holds the lower pulley in the drive system, and several of my landing gear parts, are also replaced by custom machined (by me) parts. Comparing the weight of the old and new parts revealed that I'd added about two pounds total for all of these mods.

I'm not trying to brag here; I just feel that this design may require more than the average homebuilder's skills to be constructed safely.

 

[Bill-Higdon]

How about Harvey Mace's M-102 "Scorchy" ?

 

[jlk69]

A few more general comments on the building of the BD-5, not on just its flying qualities. It's a small, lightweight airplane and in my opinion, sensitive to build quality. Weight reduction was paramount during the 5's development, so there are a lot of parts that are structurally adequate in the airframe and control system, IF built and installed properly. That means there's not much margin for overload or builder error; it is somewhat fragile to rough handling. Good workmanship is important. For example, the pitch control system is cable operated in the original design and those can easily stretch or pulley brackets deform, thus it loosens up and needs to be periodically readjusted. I completely redesigned that system in mine to full pushrod and torque tube control which provided far more positive control. I also replaced various welded, thin sheet crank arms in the control systems with custom machined parts to reduce deflection under load. Particularly for the flaps where I upgraded the stock bolts and pins at their roots that visibly deflected when I applied loads by hand. My tail section also has a few added small doublers where the stab pivots and VS attach, plus the aft end of the prop shaft. Several of these are known published aftermarket mods, and in my opinion are mandatory! At least in my plane, this has worked very well. The casting that holds the lower pulley in the drive system, and several of my landing gear parts, are also replaced by custom machined (by me) parts. Comparing the weight of the old and new parts revealed that I'd added about two pounds total for all of these mods.

I'm not trying to brag here; I just feel that this design may require more than the average homebuilder's skills to be constructed safely.

Tinbuzzard, thank you for insight and the info of the mods you performed on your BD-5. Did you ever document your mods in detail? Can you point me to any other sources for the details of any of these mods?

 

[Tinbuzzard]

Original Bede newsletters, and the BD5 Bulletin published in the mid-ninety's by Rich Perkins have a lot of these mods. I have many photos of my mods, but some require advanced machine shop capability's.

 

[Victor Bravo]

As a kid I was every bit as fascinated and inspired by the BD-5 as everyone else. The last Death Star flying scene in the original Star Wars in 1977 didn't do anything to reduce that lust, by the way.

I like to think that my skills were good enough to have flown it without killing myself, but others probably thought the same and did not live through it. Then again several of them did fly and several pilots flew them and loved them, so maybe there waas enough room for me and my Walter Mitty ego after all.

But it is fairly clear that the BD-5 might ought to never have been offered as a propeller driven airplane. The thrust line has apparently been proven over and over to be way too high for such a short fuselage. It seems to me that a BD-5 with the jet exhaust at the bottom of the fuselage below the tail would likely have been much less prone to the typical "BD-5 fatal on takeoff" accident.

EDIT: The Janowski J-5 Marco, perhaps with a little thinner wing in a "fast" version, would give you the same experience as the BD-5 intended to, but with the Grim Reaper a lot further away from you.

 

[daveklingler]

But it is fairly clear that the BD-5 might ought to never have been offered as a propeller driven airplane. The thrust line has apparently been proven over and over to be way too high for such a short fuselage. It seems to me that a BD-5 with the jet exhaust at the bottom of the fuselage below the tail would likely have been much less prone to the typical "BD-5 fatal on takeoff" accident.

As has been noted earlier in the thread, it's not a big problem unless the plane is overweight, and a large percentage of BD5 owners made their airplanes on the order of 200 pounds overweight with far larger and heavier engines. Naturally they sink a little faster with the power off.

I can't think of any accidents that occurred for this reason with planes built to spec, and as a matter of fact I'd go so far as to say that most of the accidents I've seen have been with overweight planes. There have also been a few with pilots who PIO on the first flight.

 

[Victor Bravo]

How about Harvey Mace's M-102 "Scorchy" ?

OK, ain't never heard of that one... spill it... let's see !

 

[Bill-Higdon]

OK, ain't never heard of that one... spill it... let's see !

Harvey took a BD-5 moved the wing back, put the tail wheel back where it belongs making the landing gear into a "proper" tail dragger, put a Revmaster 2100 in the nose and removes the tail shaft fairing from the tail of the airplane.