fixed vs. rectracts ... Drag and turbulence

[Bill Glaze]

Would this person be the legendary "Jersey Jim" Martin that Marguerite
Gargulio told me about?  Said I should meet him.  She said that he was
another old-timer.  (Should I have been insulted?<G>)

Bill Glaze

Mike Mueller wrote:

> Hey Dean, Jim Martin was a great pilot! Good to hear he's still
> around. Mike
>
>      -----Original Message-----
>      From: Dean Pappas [mailto:d.pappas at kodeos.com]
>      Sent: Monday, July 21, 2003 12:32 PM
>      To: discussion at nsrca.org
>      Subject: RE: fixed vs. rectracts ... Drag and turbulence
>
>      Hi Wayne,Here's what little I know from both a theoretical
>      and practical basis.In general, our open wheel wells
>      stink! They are draggy and may cause all kinds of
>      turbulence.Some ar worse than others, and there is no easy
>      way, short of a flight test or wind tunnel,of telling
>      which setups will be cleaner. Tricycle-geared retracts are
>      generally better than tail-draggers because the wheel wells
>      are aftof the wing's high-point.According to one "real"
>      aerodynamicist I spoke to, the best setups for drag
>      reduction are in order:1) retracts with good tight fitting
>      doors. 2) cleanly faired fixed gear.3) retracts the way we
>      presently do them.4) crude fixed gear.5) and retracts with
>      poorly fitting doors can possibly end up being horrible!As
>      far as turbulence goes:Our open wheel wells in the leading
>      edge made this guy cringe!He warned that poorly located
>      fixed gear can cause turbulence with the flow under the wing
>      root.Now from a practical point, I can recount my own
>      experiments and one done by Jim Martinabout a million years
>      ago. (okay in the early seventies!)I have taped the wheel
>      wells over and put small streamlined tires on both my JEKYLL
>      ( about 4 years ago) and an old tail-dragger TIPORARE (after
>      the Tangerine contest in '83). Both planes showed no
>      discernable speeddifference, but there was no fancy
>      instrumentation. The JEKYLL flew the same, but I thought
>      thatthe TIPO (named TURNARARE) rolled more nicely. I thought
>      that the transition, as I started to applythe down pressure
>      in a slow roll, went more smoothly. I eventually discovered
>      that a slack piece of tape across the wheel well in the area
>      of the wire strut gave me the same benefit. Other builders
>      make very shallow and narrow troughs for the wire, probably
>      for the same reason. Since I fly from fairly rough grass,the
>      tape allowed more strut bend without binding. Experiments
>      with big P-51 style gear doors on the Jekyll showed that it
>      was affected horribly by turbulencewith the gear down, with
>      or without the wells taped over. Result? Pants and legs
>      should be as small as practical.Jim Martin (team member in
>      '73) put heavy duct-tape over the  wheel wells of his
>      BANSHEE when he forgotthe air pump for his Rhom-Airs. Just
>      last year, he told me that he thought the plane flew maybe a
>      tiny bit better, despite the heavy tape. I hope this muddies
>      the waters adequately,    Reagards    Dean P.
>
>           -----Original Message-----
>           From: Wayne Galligan
>           [mailto:wgalligan at goodsonacura.com]
>           Sent: Thursday, July 17, 2003 4:23 PM
>           To: discussion at nsrca.org
>           Subject: fixed vs. rectract l.g.
>
>           Ok now. lets get down to the aerodynamic aspect of
>           the rectract vs. fixed gear.  Anyone have some
>           valid plus/minus on the two. WG
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.f3a.us/pipermail/nsrca-discussion/attachments/20030721/eb69b003/attachment.html