Well said Pete.
It may be worth the research and time to do the aft CG flight tests to see
if extension of the rear limit is possible. Andy may be the best guy to go
to.
Story time:
Years ago, after Sun 'n Fun, Andy and I flew, and we discussed for a moment
the extended baggage bay and gear placement when loading. Unfortunately,
our discussion was abruptly ended by the Former President of Europa Aircraf
t, Keith Wilson, who said "We spun tested and inch past the CG so who cares
, we need to go." What a nice guy.
When loading for my first long cross country with my Classic (XS cowl and F
WF and Extended baggage that was home made but nearly exact except for the
size of the access holes) I loaded as follows:
With two bags (20" airline roll around at 15 pounds each planned but really
20 pounds) 10 pounds of tools and oil in the trigear bracing, flight bag a
t 10 pounds, kids toys, hair curlers and essentials, and full fuel (new fue
l tank and filled to the neck), I computed the weight in the rear at right
at 80 pounds (or so, as I only was figuring 50). My gear legs are at 70 i
nches so all was fine until I pushed the tail down and the angle changed.
Thud, the plane hit on the tail tie down and stayed there with no one in th
e seats. A recalculation of the "needed" baggage and its placement was mad
e.
The weight and balance was computed based on the short 88 inches from the P
OH which I knew was a stretch. Bags were arranged hard at the tank as was
the tool bag and oil tucked in the X bracing of the trigear wells. Flight
bag was held on top of the roll arounds under my baggage net. Kids toys an
d hair care essentials went at the aft bulkhead and I computed the weight a
nd arm to be 62.5. It was the fuel that surprised me. The new tank held a
full 20 gallons to the top of my trigear neck not 18, why the difference I
didn't measure but the fuel was carefully checked and found to be 76 inche
s on the average from full to empty. A trigear sitting level can pack a fe
w more cubic inches in I guess. A new recalculation of the weight and bala
nce was made based on the fuel weight of the new tank and plumbing. My sca
les were giving me trouble, and it took a couple of days. Not much of a CG
change, but still my assumptions were not accurate. I needed to measure a
nd weigh both airplane and bags and their placement then test.
Of course, the Europa flew fine but the nose was just as I found in flight
testing at the full aft CG limit, just a little lighter in pitch on takeoff
and damping in flight was still superb because of the well designed tail.
It would be prudent to measure back from the joggle and recompute when plan
ning your load in any aircraft then recompute via the 29.25" and do the cal
culations for full fuel and landing fuel. The Cherokee Six is one that sca
res the heck out of me as does the Cessna 207 when I see guys loading them
willy nilly with large passengers and heavy bags.
Trust no one, verify, measure and weigh. Don't arbitrarily build an intent
ionally nose heave A.P.S for load as landing and approach light weight with
two full sized guys is a bit nose heavy in the flare. Building tail heavy
for two 250 pound pilots is not prudent either for flying solo with baggag
e. Do the measurements and calculate. It's just math. Then compute your C
G for many loadings and test carefully. I learned when converting a Zenith
601 for a very large individual (275 pounder) required me to actually weig
h the aircraft with him in it and a second pilot with and without fuel (tan
k is at the firewall and in the wings) to get a handle on his loading restr
ictions. That was my first eye opener on these small aircraft. If you ste
pped on the Zeniths aft mounted step to get in the plane with him in it and
full fuel, the plane fell on its butt and damaged the rudder. What a less
on. I was delighted with the compact arrangement of the Europa for CG cont
rol.
Within the CG limits and especially from 59-62.5 inches I find the Europa d
elightful. Make sure stab throws are near the max for assured control. Fo
llow prudent testing when near the limits of the CG. I find full forward C
G to require a slightly faster round out if the stab is only 12 degrees up
travel, and I find it more comfortable to carry 5 more knots in my aircraft
if at the full forward CG. I moved the battery to the rear when I added t
he Airmaster and have never looked back. APS is right at 59 for N12AY.
I keep an electronic fish scale (good to 25 pounds) and a tape measure hand
y when carrying props and things in the Europa that are heavy/bulky. Somet
imes when solo, I strap heavy props and things in the seat next to me.
In your computations for your POH include the various loading extremes of m
ax forward/aft possible, two pilot, fully loaded for cross country with ful
l fuel and landing fuel. It is just math. I do mine on Excel for neatness
and my Avare flight planning program now has the data for XC use. The POH
is in the aircraft with the actual fore and aft limitations on loading and
my phone has EVERY manual loaded on the cloud and the data card for the ai
rplane and its equipment.
If you are building an airplane and watching TV at night, change your prior
ities and do the research on every component in your aircraft, and for CG t
hat means loading assumptions too. YOU are the manufacturer and therefore
responsible for the safety of your aircraft, documentation, flight restrict
ions and operational limitations. Oh by the way, stay flight proficient an
d married at the same time. Aircraft builders are busy people.
Best Regards
Bud Yerly
-----Original Message-----
From: owner-europa-list-server@matronics.com <owner-europa-list-server@matr
onics.com> On Behalf Of Pete Jeffers
Sent: Thursday, April 08, 2021 5:48 AM
Subject: RE: Europa-List: Re: Weight and Balance question
ilto:pjeffers@talktalk.net>>
Hi John,
Stupid you may call the position of the zero datum but the reason is mostly
historical, very practical and it standardizes critical numbers like CG
positions across our fleet of Classics, XS's & motor gliders.
Taken in order the history started with the Classic where zero datum was th
e
front of the engine cowl. It was at this time also considered logical for
the sake of non mathematicians to keep all figures positive and not confuse
the issue with negative numbers. You don't have to look very far to find
stupid errors in critical calculations caused by deliberately introducing
negative moments.
As the XS nose was extended slightly further forward it was sensible to
leave zero datum as was. Hence the 29 3/4" point on ALL marks of Europa is
where the front of the engine cowl would have been had it been a classic.
This means, and this is important, that the CG limits and fuel tank pilot
passenger and baggage load points for all marks are consistent. It all make
s
for less risk of confusion and error.
Had the first type of Europa to be produced been an XS then zero datum woul
d
probably have been a quite different location.
Pete J
PS There may be good reason to change the baggage station of 88 ins to a
more realistic figure in light of the fact that this figure is still the
same as was applicable prior to the extended baggage bay mod.
-----Original Message-----
From: owner-europa-list-server@matronics.com<mailto:owner-europa-list-serve
r@matronics.com>
[mailto:owner-europa-list-server@matronics.com] On Behalf Of John Wighton
Sent: 06 April 2021 10:58
Subject: Europa-List: Re: Weight and Balance question
john@wighton.net>>
Gentlemen (and Ladies, if present),
All this discussion on CG moment arm made my weekend, an absolute hoot from
start to finish (is it finished yet?). This is not helped by the rather
cack-handed approach prescribed in the POH.
A reasonably common piece of data in this thread is the location of the
datum. But even that may vary depending on who/how weighed/measured the
aircraft - treat this as a variable across the fleet, but a constant for
your aeroplane. Any calculation of W&B needs to use the actual mass as
measured and the actual moment arm as measured.
Weigh the item (you, pax, the dog, grannies apple pie or your bag of
birdseed). Use that data in a spreadsheet.
Link:
https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.light
aircraftassociation.co.uk%2Fengineering%2FWeight%2520and%2520balance&da
ta=04%7C01%7C%7Cb93e6e031111465b4a4308d8fa73e64e%7C84df9e7fe9f640afb435aa
aaaaaaaaaa%7C1%7C0%7C637534722978551386%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4
wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C1000&sdata=
9drXcnFu2mH34UAQcvWMlzPWooU1Jjs%2FWsDjvkQ%2B7io%3D&reserved=0
/w_and_b_main.html
Skydemon also provides a very nice W&B calculator (it is legally necessary
to do this for EVERY flight), which makes it easy-peazy.
The moment arm I use for baggage is a measurement to the centre of the bay.
However, the Europa Aircraft method of establishing the FS 0.0 datum is a
comedy. A position 29.25" fwd of the "Rear of joggle for cowling in
fuselage moulding" needs to be marked.
This is totally unnecessary - the cowling to fuselage joint is as good a
datum as any. It requires all moment arms forward of it to be given a
negative sign (for the initial W&B calculation and any subsequent firewall
forward mods) and all those aft of it to be positive.
Just measure along the horizontal fuselage datum WL (level sill can be used
as per POH) to the FS of the item to be measured.
Attached is an extract from the POH (note the depicted Trigear also has a
secreted mainwheel protruding from the fuselage!).
--------
John Wighton
Europa XS trigear G-IPOD
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