On take off 60 mph is 88 feet per second. 1 g is 32 ft/sec squared
3 seconds to get to 96 feet per second take off speed at 1 G acceleration

As a first guess on the drag bucket 125 MPH is 183 feet per second best climb speed for an RV4. Best climb speed occurs in  the drag bucket where induced drag equals aero drag.  I will nail this down further later on. The lower
the drag bucket speed the better.


45 degree angle gives us 130 ft/sec straight up.
for 80 seconds that gives us 10,400 feet

From an Otis elevator point of view that is 130 X 1000 pounds or 130,000 ft.lb/sec HP divided by 550 (the HP constant) we get only 236 climb HP.
Not counting total aero drag. Non induced drag is down in the noise.

Lets say the prop is 80% efficient that is .8 times 650 HP or 520 net thrust HP.

550 times 520 ft,lb./second  divided by 183 ft/sec is 1560 pounds of thrust.
I doubt it is that high. My guess is more like 1000 pounds of thrust.

We can measure the static thrust with a calibrated garage door spring and see how close it comes. The thrust will increase when the prop comes out
of stall. We can also do a drag race and time it to 60 MPH. Some thing that
was done on the Ruttan Voyager with my test equipment by Road & Track.


More on this later as I will calculate the induced drag which is a strong
function of weight and wing aspect ratio. That is why airliners are
using wing lets. We should build carbon fibre tip extension to improve
the aspect ratio. C sub l squared and C sub l is directly proportional to weight.

Do away with the canopy and save the weight. Go open cockpit and the pilot can bail out more easily  in case of an in-flight fire.

Check my arithmetic carefully as I have been known to make mistakes :)

Robin is getting better fast and it looks like we will be able to come back
from OZ on Wednesday.

Paul Lamar

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