"J.Kahn" wrote in message
...
Juan Jimenez wrote:
"J.Kahn" wrote in message
...
The lack of crashworthiness inherent in the BD 5's configuration makes
engine reliability really critical. In the end the jet version is
probably the safest one due to the better reliability of a turbojet.
Actually, both of these statements are incorrect.
These two pictures show what's left of a Canadian BD-5 that landed in a
raspberry patch and essentially tore itself apart.
http://www.bd5.com/Canada/Canada01.jpg
http://www.bd5.com/Canada/Canada02.jpg
The man holding the pieces is the builder and pilot. He walked away.
About 30% of accidents involving BD-5's are fatal. 23% of RV-6 accidents
have been fatal, and that's not counting the fact that some of those
accidents had more than one victim. You can verify that yourself on the
NTSB web site.
The Microturbo TRS-18 that is most commonly used on the BD-5J is a very
finicky engine in many respects. For example, any minor deviation on fuel
pressure can cause the engine to shut down. The fuel pumps are very
critical components, which is why at least one of the operators is
heavily involved in designing replacement components and reengineering a
portion of the fuel system to increase reliability in this area. The
irony is that even though BD-5J's are mostly used for homeland security
as cruise missile surrogates, Microturbo, with facilities in Grand
Prairie, TX, refuses to cooperate. They won't even sell parts, directly
or through the military.
I see your point Juan, although I could probably spin that around and say
it has a "76% higher fatality rate than an RV-6!" 
LOL! We have another statistician in the house. God help us.
Obviously you're dead as a doornail in a stall spin accident in either
airplane. What would be interesting to see is the survival rate of BD-5
vs other homebuilts in a controlled forced landing, which when you get
down to it is the key issue that I would worry about.
I've had several friends who had engine issues and had to do forced
off-field landings. All of them walked away. I have not done the statistical
comparison, and frankly I don't have the time to find the data and run the
numbers. Maybe someone else would like to try that. The ones who have not
walked away wind up in that situation because of their own doing. For
example, a BD-5TP pilot who is doing flight tests out at Mojave and then,
out of the blue and only a few hours into phase I, decides to come back to
his home field in a dense urban area, where there are no options if you lose
the engine on takeoff. The result was regrettably predictable.
I would think the ideal engine would be a properly developed wankel.
If you added the word "installation" to the end of that sentence, then I
would agree 100%. There is a BD-5 sitting in England with a Midwest Rotary
engine. It's been ready to fly for quite some time (and actually flew with
another engine). The CAA in the UK has essentially reached the conclusion
that UK pilots are not good enough to fly the BD-5 and have refused to allow
the aircraft a renewal of the permit to fly. The problem with a rotary is
the same as with other engines in the confines of the BD-5 engine
compartment -- cooling. From what little I know about these types of
engines, they generate a lot more heat than regular piston engines, and that
places an even higher burden on heat dissipation, which the BD-5 is simply
not very good at. Getting rid of heat on a BD-5 is probably one of the most
demanding tasks for the builder.
Juan
--
Posted via a free Usenet account from
http://www.teranews.com