As I recall it was the Ford Thunderbird SC 3.9L V6 engine with the
supercharger. Dyno readings can sometimes be misleading depending on who is
running it. Was that the HP number Dave Blanton was claiming or was that
done on
an independent shop dyno. There was a lot of controversy about that as
Blanton did not use the same measure of HP as the rest of the world did (and
still does).
My 1994 Mercury (Ford) Cougar over head cam 4.9L V8 is only rated at 200 HP.
My guess is a stock Ford push rod 3.9L V6 is about 160 HP.
Here are a couple of pictures of the engine. Firewall forward weight is over
500 pounds.
Paul Lamar
Paul;
The pictured engine is in my BD-4. Our discussion at Oshkosh sprang from my
wish that I had an in-flight adjustable pitch prop. My pitch is currently
set to redline the prop (2700 RPM) at full power at my normal cruise
altitude of ~5000 ft. In climb out at 90 mph, I can achieve 1667 FPM at
~2300-2400 Prop RPM [4080 engine RPM] at my normal flying weight. 1600 FPM
isn't too bad at 2100 lbs, but if I had a variable pitch prop, I could
develop full power during climb and get closer to 2000 FPM.
I wasn't thinking what this "hand grenade sounded like running at full
power" when you suggested looking at a higher PSRU ratio. All I could see
was $$$$$. The engine is very smooth at full power and emits a pleasant,
masculine supercharger whine.
The 3.8L SC engine is rated at 210 HP in the car. While I have never had it
on a dyno, I have no doubt that I am achieving something in that range or
better. I'm very pleased with the performance of this engine, but I would
be even happier if it had a two speed transmission.
Before buying an in-flight adjustable prop, I will change the pitch on the
Warp drive from 17 to ~12 degrees of pitch at the tips, then record the
climb performance.
Keep up the good work on the NG. I'm learning a lot lurking in the bushes.
John Steere
Thanks for clarifying the numbers John.
Yes on your SC HP. I was referring to the normally aspirated V6 mentioned by
Holger. I was not clear on that point. I am looking forward to the data at
12 degrees of pitch on the Warp drive prop.
1600 FPM is 26.6 FPS straight up with 2100 pounds is 56,000 pound foot per
second or 101 net HP required for climb alone. This is net HP out of the prop
so giving the prop the benefit of the doubt at 80% efficient that is
127 HP out of the engine. This is just the climb HP required to lift that
weight at that rate so the aerodynamic drag is not included in this
calculation however it is rather low at only 90 MPH.
Calculating the drag... giving things again the benefit of the doubt.
At a flat plate equivalent of three the drag would be 90^2 X .0026 X 3
or 63 pounds of drag. 90 MPH is 132 feet per second so 63 pounds of drag
times 132 FPS is about 8300 pound feet per second or about 15 net HP out of
the prop. Out of the engine it is 15 HP dividing by .8 or 19 HP for a total
of about 146 HP out of the engine. Probably a bit more as induced drag from
lift is a factor at 90 MPH. 90 MPH is usually a bit below the bottom of
the drag bucket MPH.
I still think you need to get the RPM up to at least 4500 on the engine
somehow. I think you would still be better off cutting down the diameter
of the prop.
What is your top speed so far John?
Paul Lamar
Having owned & flown a Lyc 180hp/cs prop 'stock wing' BD-4, I can tell
you that his climb rate is much better than I would have expected
hauling that kind of weight if he has the stock wings (not longer span).
I flew mine to OSH a couple of years ago with a neighbor in his C-182.
He was at gross weight & I was at my gross of around 1900 lbs. We would
break ground at around the same spot, I could rather easily outclimb him
and pass him on climbout (100mph vs 120mph climb speed. I could outrun
him below about 6k feet & he could outrun me up higher. Neither of us
had wheel pants & our cruise was around 150-155 statute mph. I don't
think I saw more than 1300 fpm when fully loaded. If John is doing 1600
fpm at 2100 lbs with a fp prop pitched for cruise, he's beating a 180
Lyc. My plane was rather dirty, but at 100mph climb speeds that wouldn't
make a lot of difference.
Charlie England
What are the two spans? What is the cord?
Paul Lamar
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