One of the great things about the BD4 is the never exceed speed of 234
MPH. This means you can use a 350 HP turbo 2 rotor and cruise at 200
MPH. That is far far better than a $750.000 brand new Cessna 182. You
can probably get 90 gallons of fuel in it as well. Vans airplanes have a
never exceed speed of only 200 MPH. If you install breathing oxygen you
can do it at 18,000 feet as well with out going IFR.
The BD4 is a high performance four place kit aircraft and as such
is a real bargain. Easy to build as well. Paul Lamar
Paul, where does the BD4 get it's good performance specs from?
Steve Carlisle
No rivets in the wing skin and no struts like a 182.
It is also carefully stressed by a talented engineer.
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The tube spar is a bit heavier than need be towards the outer ends
but it is big labor saving device.
Later versions of the BD 17 tube spar where placed in a big lathe
and the wall thickness was turned down between the ribs.
Probably too expensive.
Then after that they started cutting large holes in the front and
back side of the tube spar to save that weight.
That will also increase the amount of fuel that can be carried.
http://www.bedecorp.com/bd-17l.html
Peter Garrison wrote a good explanation of the tube spar
advantages and disadvantages.
Here is his article in jpg form.
Also a picture of the BD spar with large holes.
Paul Lamar
Paul, thanks, I though it would have been more than that. A lot of
these specs are overrated, as some would say!
Steve Carlisle
There are so many flying that the claims are probably more accurate
than most. The new factory made wing is a work of art.
This airplane is the biggest bargain in the world in terms of performance
per dollar.
http://www.bedecorp.com/bd-4c.html
At a cruise power of 170 HP and a Mazda rotary leaned to a BSFC .47 you
burn
about 12.7 gallons an hour and go 221 MPH. That is 6.3 hours and
almost 1400 miles. That is out standing. The max range on my
C182 with 90 gallons is 1100 miles and that takes 7.3 hours at 150 MPH.
80 gallons of fuel is 500 pounds. That gives you 610 pounds left
of useful load left. Another 400 pounds of fuel in the back seat
would give an additional 1100 miles of range for a total of 2500 miles.
You could
fly to Hawaii from SFO with that range. Also cross the Atlantic.
That leaves 210 pounds for the pilot. Actually most ferry flights take
off well over gross. With a turbo rotary making 400 HP on gasoline taking
off well over gross is no problem at all. You burn off a lot of weight the
first few hundred miles. The BD4 has Ultimate G Load Limits well
over most certified aircraft at +/- 6.3 G so that makes taking off
over gross much safer.
As I said this is an out standing airplane.
Paul Lamar
Paul, I had been thinking for a while that although my fibreglass wings
look superb from what I have read most have suffered from leaking fuel
at some time and I am not impressed with the idea of just putting more
and more goo in and around the tanks. They also suffered from fuel
shortages for various reasons which the insurers cottoned on to at one
time .
So I wondered if an alloy tank in place of the back seat would not be a
simple and safe alternative. Sure it would reduce the seating capacity
but for me I wouldn't be happy to load up four people into a homebuilt.
Rather if this aircraft could get me the 1200 miles to the south of
France with good reserves I would be tickled.
Where I get stuck at this point is what would happen to weight and
balance with just 200lb pilot in the front and 400lb fuel behind the
seat ( Tank could be tall and thin depth wise so it was as close as
possible to cg) and nothing in the wings.
Mark Dillner
So that is why they moved away from that fiberglass configuration.
Are yours actually leaking?
Yes tall and thin. You will need to do a CG calculation.
There is info on the CG in the plans. Do you have a set?
The fuel weight is located at 90 inches.
front seat weight is located at 94 inches
rear seat weights are at 127 inches.
The CG needs to be at 80 to 90 inches.
According to my set of plans.
Paul Lamar
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