Re: Benefits of streamlining Happy New Year

Mike Dwyer <mdwyer@...>

There are too many variables. As you descend the load on the prop is less so the RPM increases, this in turn increases the power out of the engine. Each prop performs differently. So now you got a throttle setting variable, a prop variable, an engine power variable.

Best to drag a Q over to the NASA wind tunnel.

Straight down with power on the Q200 will probably go 500 mph? Would probably get to 350 mph before the control surfaces depart the airframe. I've been at 250 TAS in a slight descent.

Mike N3QP Q200

Sam Hoskins wrote:

Jay, this sounds like a neat idea. I might take you up on the test.

No way, however, am I going to point the nose straight down. :>)


On Sun, Jan 2, 2011 at 10:05 AM, Jay Scheevel <scheevel@...> wrote:

Charlie wrote:

."Some one could do the dive test with a GPS to plot the L/D = Velocity h/

Velocity v = slope of the exponential curve. Point one straight down I
think the wall will be a lot higher than 220 MPH. I have been at 180
indicated in my old Dragonfly coming down final for a low pass with 55 hp.
Low drag and cubic horsepower proceeded by cubic dollars equal winning
plane. Just my

$.02 and opinion not backed by facts."

Sometime back, I challenged folks with flying Q's to give this a practical
test and help put some numbers on the chart. Jim always says ".Now Go
Fly!". Who would like to follow his advice and send me some airspeed vs.
decent rate numbers..See my previous comments below...

"1 horsepower corresponds to 542.5 foot pounds/second (or about 32550 foot
pounds/minute). So if you put your plane, loaded to something like 1000
pounds, into a steady 1000 fpm descent rate and the speed stabilizes to 220
mph, then you are adding .30.72 horsepower. If you had to go to 2000 fpm to
get up to 220 mph, then it would be adding 61.5 additional horsepower and
forth. So if you think your plane should fly 220 mph, then find the descent
rate necessary to achieve this speed, then compute how much more horsepower
you would need.

It would be fun to make a chart of airspeed as a function of decent rate
(holding the engine settings constant at level cruise settings). If this
chart was done for every flying Q out there, then we could see the range of
effective performance for each unique airplane. Compiling this info would
also make a very effective follow up to my wing incidence study and I would
be happy to do it.

...what do you think guys? Could you gather me some more data to


Jay Scheevel - Tri-Q, still building


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