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Re: Europa-List: Monowheel to trigear conversion - figures

Subject: Re: Europa-List: Monowheel to trigear conversion - figures
From: Bud Yerly <budyerly@msn.com>
Date: Tue, 21 May 2013 11:56:46
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5&authkey=!AKnPGp8SHrmYj5k> 
Frans, but mostly for others reading this stuff:

I believe that a two part fairing is the answer.  I don't have time to 
finish it as we are swamped, but the forward fairing I use is left 
nearly as it is now.  It bolts to the bracket using two nutplates (my 
usual way to install the outer bracket).  I fabricated a flap fairing 
---From foam that fits into the slot on the forward bracket to get rid of 
that nasty gap at the back.  Cleaner aerodynamically, but what a bugger 
when it comes to the annual inspection.  I now use a screw attach on the 
forward cover to the wing and to the bracket of course, and just a bit 
of white caulk to seal the edge.  Drill a hole in the bottom of the 
cover for water of course.

My rear fairing will be added to the flap and attached with adhesive 
sealant.  I got stopped when I was trying to keep the gap sealed through 
full flap travel.  Also, for the mono, the flaps will weigh more and I 
think that my induce a bit of droop which the owner did not have with 
his current setup.

The Europa inner brackets will look awful unless spacers are planed to 
keep them from distorting.  Again, they are not as important as the 
outer, but the plane looks more complete with them.

Pay attention to gear leg covers, transitions and wheel pant height and 
alignment.  A droopy wheel pant is like a parachute.  The lower the 
wheel pant (no lower than the bottom of the wheel rim), the better the 
speed.  For grass strips, well compromises have to be made.  Lift the 
pant up to prevent the rear lip from tear out from the grass whipping 
it.

12AY went from 107 with a fixed pitch Warp Drive set at 5200 static on 
the 914.  With the Airmaster I jumped to 117 KTS at 1000 MSL 
(914/Airmaster 332) and now at the same power setting of max continuous 
(34 inches/5500 RPM) it does right at 136 KTAS.  With some tuning and 
tweaking and only one on board a 920 lb empty weight aircraft and all 
polished up, I hit 146 KTAS at 1000 MSL in the traffic pattern (I fixed 
the stock 914 inlet duct cowl seal leak at the rear also which was like 
a parachute).  These cleanups allow a 26 inch/ 5000 RPM cruise at 
1000MSL of 127 at about 4.5 GPH.  Obviously at 8500 MSL my true airspeed 
is quite comfortable at 130 ish to get 28 NM/Gal which is over 30 Statue 
MPG.

(Airspeed calibration is less than 2 knots below 100 KIAS and spot on 
above 100KIAS to 160KIAS.)

Our last Europa XS, High Top, at 1400 lbs. as tested, equipped with 912S 
with Airmaster AP332 does 136 Knots at 1000 MSL at 26 inches and 5500 
RPM just using the above techniques.

Gear leg covers add speed, pay attention to the details and think like 
an air molecule.

A bit of work with clay and filler and you can get a few more knots, but 
much more fuel efficiency.  Pay attention to your cowl duct seals also.  
That is more knots than you think also.
Finally, the rig of the aircraft makes a big difference.  Droopy flaps 
are the worst.  If all is not straight at cruise, (trim tabs also) it 
slows you down.

Regards,
Bud Yerly
      
<https://skydrive.live.com/redir.aspx?cid=2161856909618aa7&page=play&;
resid=2161856909618AA7!347&parid=2161856909618AA7!346&type=1&authke
y=!AKnPGp8SHrmYj5k> Typical glass up of fairing.  Note it is not a 
thing of beauty at first, but it fits the leg.  This photo makes it look 
like the front has a flat bottom, but that is an optical illusion.  
These are my flip up pant inner brackets.  NOTE:  The inner bracket is 
attached to the metal bracket.  Cuts in this are for the gear inner 
bracket to be able to be removed for a brake job. 
      
<https://skydrive.live.com/redir.aspx?cid=2161856909618aa7&page=play&;
resid=2161856909618AA7!348&parid=2161856909618AA7!346&type=1&authke
y=!AKnPGp8SHrmYj5k> Pay attention to allow for flex and filler and 
paint.  Use a block sander and square up your final install. 
      
<https://skydrive.live.com/redir.aspx?cid=2161856909618aa7&page=play&;
resid=2161856909618AA7!349&parid=2161856909618AA7!346&type=1&authke
y=!AKnPGp8SHrmYj5k> Aft portion of this cover has a small amount of 
gap to allow for gear flex also.  It is a great idea to use clear 3M or 
glider wing tape as an anti chafe for your paint.  These joints flex.  
(This gear is flexed with 400 lbs in the seat and full gas and you can 
see it just touches. 
      
<https://skydrive.live.com/redir.aspx?cid=2161856909618aa7&page=play&;
resid=2161856909618AA7!350&parid=2161856909618AA7!346&type=1&authke
y=!AKnPGp8SHrmYj5k> Keep it small and simple.  Bigger is not better.
      Note these are the standard Europa supplied pants, so the cut is 
right down the center of the fairing.  You can make a joggle if you 
wish, but it is not necessary if your gaps are small and are glass, not 
filler. 
      
<https://skydrive.live.com/redir.aspx?cid=2161856909618aa7&page=play&;
resid=2161856909618AA7!351&parid=2161856909618AA7!346&type=1&authke
y=!AKnPGp8SHrmYj5k> This nose gear cover is a bit high so the shimmy 
dampener is visible for grease leakage.  The pant is made with the hinge 
line set on an angle to allow quick access to the nose wheel for 
servicing and inspection. 

  ----- Original Message ----- 
  From: Frans Veldman<mailto:frans@privatepilots.nl> 
  To: europa-list@matronics.com<mailto:europa-list@matronics.com> 
  Sent: Tuesday, May 21, 2013 5:43 AM
  Subject: Re: Europa-List: Monowheel to trigear conversion - figures


  On 05/21/2013 02:30 AM, Robert Borger wrote:

  > Eventually, the rest of the speed kit (flap hinge fairings) will go 
on and we'll see how that helps.

  Don't do the flap hinge fairings. They are very bad. They increase the
  frontal area many times (pressure drag), increase the side area (skin
  drag) and worst of all, they have an opening at the rear which is the
  worst aerodynamic thing you can imagine. The hinges are fine as is,
  leave them alone, except for the outer one (the double one), but this
  one can be modified (or you could create a better fairing for it). To
  give you an idea for a better "outer flap hinge fairing" look at the
  attached pictures. I made a mold but never installed these fairings as 
I
  decided later to modify the flap hinge itself.

  Frans


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