Quote:
Originally Posted by rfdesigner
I think we'ce all seen the aero civic but I think the aircraft the AR-5 and it's follow on the AR-6 racer may have taken things a little further... and all starting about 16 years ago!
Now sadly I can't post a link officially until I've posted 5 posts here.. this is my fifth, so I hope the moderators will tolerate a little bending of the rules
the URL is
dubdubdub dot AR-5 dot com
Just to summarise why I've posted this.
This aircraft achieves 207mph on just 65hp!... by my calculations that's 32mpg @ 207mph (assuming 20% thermodynamic efficiency)... hence the title of this post. More importantly he seems to have gone further than just making it slippery, he did some very careful design around joins between sections etc.
It made me wonder if the same technique could be used on belly pans (keep the area of the gap beneath the car the same at every point along the length, so raise the pan a little at the axles.. if there's room of course).
Derek
|
Kenny Lyon's Cd 0.11, Becker-Lyon motorcycle streamliner does 207-mph with 150 Bhp,in ground-effect with tires on the ground,so 207mph with 65 Bhp sounds very reasonable for an aircraft.
The mpg would vary as a function of load and BSFC map of course.
I don't know about the Cd figure.Abbott and Von Doenhoff ( sp?) warn about using any aeronautical values outside of 'flight conditions.'
My opinion is that Cd 0.016 should be 0.16.The fuselage cannot be lower than Cd 0.04 in free flow and that would put it at Cd 0.08 in ground proximity.Adding 'skinny' tires would push it to Cd 0.12,same as 1953 MG EX 181,or GM Sunraycer ( 1987 ).
If it's a 'laminar' aircraft you can increase the Cd significantly,as it is not possible to have laminar flow above critical Reynolds number in ground-effect.( 20-mph up ).