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Subject: Stick Force per G
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I looked at the CAFE reports and at FAR 23.155 (the FAR which regulates el=
evator forces in small airplanes).  The regulation requires a minimum of=
 15 pounds of aft stick force to go from cruise to maximum G (4.5 G for th=
e 320, per the POH).  That would represent 4.3 pounds per G if the stick=
 force gradients were linear.  It also allows some decrease in stick force=
 gradient (designers usually try to avoid this) as long as it is not "exce=
ssive".

Here are the aft stick forces required to obtain one additional G (i.e. to=
 go from trimmed one-G flight to 2 Gs) for various airplanes.

1)  The Cessna 152 -- 20 pounds of aft stick force

2)  An RV-8 -- 11 pounds of aft stick force

3)  An RV-6, a Lancair Legacy (N199L), and a Lancair 320 (Fred Baron's air=
plane) -- all about 4 pounds of aft stick force

So it appears as though the Lancairs are at or very close to (and maybe sl=
ightly below) the minimum stick force per G for a certified airplane, but=
 surprisingly similar to an RV-6.  The RV-8 and the Cessna 152 are well ab=
ove the minimum stick force per G for certified airplanes.

But ...

Never forget that the FARs are intended to keep the lowest common denomina=
tor safe.  The "Joe bag of doughnuts" weekend VFR flyer who just got his=
 license.  No offense is meant here.  I was Joe for a long time.  (And my=
 favorite is a chocolate glazed -- not chocolate frosted -- doughnut.)  Th=
at's why I flew Cessnas early in my flying career.  There is nothing inher=
ently wrong with a more skilled pilot flying a more maneuverable airplane.=
  Lancairs have long been advertised as the "Ferrari of the skies" and I'd=
 never give my sixteen year old kid the keys to my Ferrari (if I had one,=
 that is).  But it does suggest that the safety margins are smaller in the=
 less forgiving Lancair, but also for the RV-6, which nobody thinks of as=
 dangerous.  It's obviously not the whole story.

However ...

The CAFE guys did not go all the way to 4.5 G -- they stopped at 3.5 G. =
 So the data is not 100% there.  We have to extrapolate to determine if th=
e FAR requirement is met.  The Legacy looks pretty linear (stick force vs=
 G) and appears as though the minimum stick force at maximum G would be so=
mewhere between 15 and 20 pounds at 4.5 G -- the FAR requirement therefore=
 appears to be met.

The 320, on the other hand, looks pretty good at forward CG (extrapolates=
 to 19 - 20 pounds at 4.5 G) but no so much at aft CG, where the stick for=
ce gradient decreases (although not excessively) and it extrapolates to on=
ly about 11 pounds for 4.5 G.  Not so good.

That's troublesome, at least to me, and is why I have strived to make my=
 CG forward.  Long engine mount, battery in the engine compartment, hydrau=
lic pump forward of the instrument panel are the big things I've done.  I=
 also convinced my wife that I bought the higher-power 360 engine on the=
 basis of safety, since it adds weight to the nose of the airplane.  (No,=
 she didn't believe my rationale but agreed to look the other way, and no,=
 she does not have a sister.)

Take this data as you will.  I think we all agree that the Lancair is not=
 for the beginner pilot, and here we have some regulatory guidance suggest=
ing why.  Experience and training act together to mitigate the reduced saf=
ety margins of a maneuverable airplane, and the Lancair is no exception.

- Rob Wolf

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<font color=3D'black' size=3D'2' face=3D'arial'>
<div>I looked at the CAFE reports and at FAR&nbsp;23.155 (the FAR which re=
gulates elevator forces in small airplanes).&nbsp;&nbsp;The regulation&nbs=
p;requires a minimum of 15 pounds of aft stick force to go from cruise to=
 maximum G (4.5 G&nbsp;for the 320, per the POH).&nbsp; That would represe=
nt 4.3 pounds per G if the stick force gradients were linear.&nbsp; It als=
o allows some decrease in stick force gradient (designers usually try to=
 avoid this) as long as it is not "excessive".</div>


<div>&nbsp;</div>


<div>Here are the aft stick forces required to obtain one additional G (i.=
e. to go from trimmed one-G flight to 2 Gs) for various airplanes.</div>


<div>&nbsp;</div>


<div>1)&nbsp; The Cessna 152 -- 20 pounds of aft stick force</div>


<div>&nbsp;</div>


<div>2)&nbsp; An RV-8 -- 11 pounds of aft stick force</div>


<div>&nbsp;</div>


<div>3)&nbsp; An RV-6, a Lancair Legacy (N199L), and a Lancair 320 (Fred=
 Baron's airplane)&nbsp;-- all about 4 pounds of aft stick force</div>


<div>&nbsp;</div>


<div>So it appears as though the Lancairs are at or very close to (and may=
be slightly below) the minimum stick force per G for a certified airplane,=
 but surprisingly similar to an RV-6.&nbsp; The RV-8 and the Cessna 152 ar=
e well above the minimum stick force per G for certified airplanes.</div>


<div>&nbsp;</div>


<div>But ...</div>


<div>&nbsp;</div>


<div>Never forget that the FARs are intended to keep the lowest common den=
ominator safe.&nbsp; The "Joe bag of doughnuts" weekend VFR flyer who just=
 got his license.&nbsp; No offense is meant here.&nbsp; I was Joe for&nbsp=
;a long time.&nbsp; (And my favorite is a chocolate glazed -- not chocolat=
e frosted --&nbsp;doughnut.)&nbsp; That's why I flew Cessnas early in my=
 flying career.&nbsp; There is nothing inherently wrong with a more skille=
d pilot flying a more maneuverable airplane.&nbsp; Lancairs have long been=
 advertised as the "Ferrari of the skies" and I'd never give my sixteen ye=
ar old kid the keys to my Ferrari (if I had one, that is).&nbsp; But it do=
es suggest that the safety margins are smaller in the less forgiving Lanca=
ir, but also for the RV-6, which nobody thinks of as dangerous.&nbsp; It's=
 obviously not the whole story.</div>


<div>&nbsp;</div>


<div>However ...</div>


<div>&nbsp;</div>


<div>The CAFE guys did not go all the way to 4.5 G -- they stopped at 3.5=
 G.&nbsp; So the data is not 100% there.&nbsp; We have to extrapolate to=
 determine if the FAR requirement is met.&nbsp;&nbsp;The Legacy looks pret=
ty linear (stick force vs G) and appears as though the minimum stick force=
 at maximum G would be somewhere between 15 and 20&nbsp;pounds at 4.5 G --=
 the FAR requirement therefore appears to&nbsp;be&nbsp;met.</div>


<div style=3D"CLEAR: both">&nbsp;</div>


<div style=3D"CLEAR: both">The 320, on the other hand, looks pretty good=
 at forward CG (extrapolates to 19 - 20 pounds at 4.5 G) but no so much at=
 aft CG, where the stick force gradient decreases (although not excessivel=
y) and it extrapolates to only about 11 pounds for 4.5 G.&nbsp; Not so goo=
d.</div>


<div style=3D"CLEAR: both">&nbsp;</div>


<div style=3D"CLEAR: both">That's troublesome, at least to me, and is why=
 I have strived to make my CG forward.&nbsp; Long engine mount, battery in=
 the engine compartment, hydraulic pump forward of the instrument panel ar=
e the big things I've done.&nbsp; I also convinced my wife that I bought=
 the higher-power 360 engine on the basis of safety, since it adds weight=
 to the nose of the airplane.&nbsp; (No, she didn't believe my rationale=
 but agreed to look the other way, and no, she does not have a sister.)</d=
iv>


<div style=3D"CLEAR: both">&nbsp;</div>


<div style=3D"CLEAR: both">Take this data as you will.&nbsp; I think we al=
l agree that the Lancair is not for the beginner pilot, and here we have=
 some regulatory guidance suggesting why.&nbsp; Experience and training ac=
t together to mitigate the reduced safety margins of a maneuverable airpla=
ne, and the Lancair is no exception.</div>


<div style=3D"CLEAR: both">&nbsp;</div>


<div style=3D"CLEAR: both">- Rob Wolf</div>
</font>

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