Whittier Narrows California, September 18, 2010

Class A and B records were set at meet today.

Class A Howard Doering  110.66 MPH

Class B  Will Stewart       142.46 MPH

Scott,

Howard's A ship uses top of the line Neu components.  Am not sure about his ECU, but the timer is, like mine, from Will Hublein.  The airplane is his old record holder from the mid nineties, modified to accept a  5A LiPo, which expanded the fuselage to resemble a Grumman Avenger.  Pix should appear in the Speed Forum soon.

My ship uses the same AVEOX 1415-2Y I was using 15 years ago, with the Hall effect sensors removed and a Castle Creations Phoenix 80 ECU.  The battery is a cheapie 6S 3A-40C from Red China.  The ship itself has 108 sq in wing area and about 33 stab.  It uses the dread 'wing tip bellcrank' so feared by mid-west Sport Jet types.  The prop was a maple 8/8 which I carved using old time technology.  This natural composite material still has some advantages, even at high RPM.

Now that we wil have to increase line length and diameter to stay in conformance with AMA guidelines, future speed will probably be at least 15 MPH slower.

Build an electric speed ship and join the fun.  Since a long skid is needed to protect the prop, Form 40 landing gear would not be much of a handicap and would eliminate the complication of a takeoff dolly.

Will

Scott,

Responding to your message in this forum and your recent e-mail.

The wing tip bellcrank, as used in my Sport-Jet ships is about as you described in your e-mail- the bellcrank located at the inboard wing tip, moving a pushrod positioned spanwise behind the trailing edge of the inboard wing. This pushrod is linked to a small triangular bellcrank behind the wing which connects to the elevator control horn.  All in keeping with the original North American Speed Society Sport Jet rules which require the entire control system to be external to the normal contours of the airplane.

Why bother?  The couple of feet of control line normally running over the wing to a conventional bellcrank location are the fastest moving highest resistance part of the line system. The spanwise pushrod is submerged in the wing's boundary layer and adds no drag.  Does it work?  My ships, under the old fuel rules recorded flights about seven MPH faster than the NASS 'sportsmen' who pushed through the rules change outlawing them- (165 MPH).  On the new jet fuel, I believe the results so far with the wing tip BC are still at least five MPH faster than the next quickest Sport Jet- (158 MPH).

The S-J rules change disqualifing my ships specifies that the BC be located within four inches of the fuselage and specifically eliminates the spanwise pushrod.  My 'New Rules' SJ is sitting on my desk as I type this, ready for the December Toys For Tots contest, and should have a similar low drag advantage.  We'll see.  If it works, and is written out of the 2012 NASS rules, there is still another configuration waiting, after all this is what I spent my career in aerospace doing and enjoying!

The only reasons I used the wingtip setup in the 142MPH B Electric is to eliminate some binding with the internal BC under the 85# pull and for fun.

Regards,  Will Stewart  AMA 1947