Pietenpoi weight and balance Página 1 de 2
by
Jack Broomall
22200 Heatheridge Lañe
Northville,MI48167
and
Don Verdiani
103 Lockerbie Lañe
WestChester,PA19382
Those of you who were fortúnate enough to attend Brodhead '94 may know that we were able to
measure weight and center of gravity information for eight of the aircraft attending the event.
The reason for imdertaking this exercise was to provide a bank of information that Piet builders
could refer to and use in confíguring their aircraft. Over the past several years we have noticed that
there are a variety of types of Air Campers flying with different engines, at least two common
fuselage lengths, different wing positions, and different flying characteristics (if you doubt this take a
cióse look at the various aircraft taking off and landing at Brodhead!). Collecting the weight and
balance information on a number of flying aircraft seemed like a good way to gain some insight in
this área.
The data table (below) summarizes the most important information which was accumulated.
We were fortúnate to be able to inspect examples of each of the three most common powerplants
(Ford, Corvair, and Continental).
In the third column we categorize the fuselage as 'short' (the original design) or long (the so-ealled
'improved' air camper).
In column 4 we show the aircraft's empty weight. In each case the aircraft was presented for
weighing with some amount of fuel on board. We asked each owner to estímate how much fuel was
in the aircraft, and then corrected to an empty weight using that estímate and the standard valué of 6
Ibs. per gallón for gasoline.
While there is some degree of'estimating' in these numbers, we are comfortable that they are
reasonably accurate.
In the fifíh column, we show the empty aircraft's center of gravity location with respect to the wing
leading edge. We chose the wing leading edge as a datum because it was the best way to normalize
the data to a large variety of aircraft and also because that's what Mr. Pietenpoi used!
For comparativo purposes there is a published weight and balance summary, done in 1965, showing
a Corvair powered Air Camper with an empty C.G. 8.71 inehes aft of datum. Very few of us fly
airplanes empty, with no passengers! Fortunatly, using the data we collected, we are able to calcúlate
center of gravity location for any loading condítion.
In the sixth column, we show the calculated C.G. location when the aircraft was loaded with an FAA
standard 170 pound pilot in the back seat, and 7 gallons of fuel in the 'main' fuel tank. This might
represent a 'typical1 loading for pilot only. Since we weighed some aircraft with both wing tanks and
fueslage tanks we elected to (mathematically) put the 7 gallons of fuel in whichever tank was bigger.
Again a comparison is available.
The previously mentioned weight and balance chart included a C.G. calculation for that aircraft with
7 gallons of fuel and a 166 pound pilot on board (Did BHP weigh 166 pounds?). His example
aircraft has a C.G. 9.51" aft of datum in that loading condition.
Pietenpol weight and balance Página 2 de 2
As a final set of calculations we've shown aircraft weight and C.G. location when each aircraft is
loaded with a 170 pilot, a 170 pound passenger, and it's fuel tank(s) full. These weights are shown in
column G and the C.G. location is in column H. We found these weights interesting in that some of
the aircraft have surprisingly high gross weights. Also, there are several aircraft which, in one
loading condition or anotner, seem to viólate BHP's recommendation to never exceed 20" aft of
datum C.G. (also shown in the 1965 weight and balance sheet).
Because of the conditions under which all of our information was collected and because there was no
chance to double check any measurements there is some real chance that there may be errors in our
analysis. However, there is enough consistency in the data to feel fairly confldent about it's accuracy.
We would like to thank all the fine folks at Brodhead for helping us with this project. And special
thanks are due to the eight aircraft owners who donated their aircraft as well as their time and help.
We'd like to think this activity has produced information of real valué to the community of Pietenpol
builders and pilots! Any one who has any questions can feel free to contact either of us at the
addresses above.
Pietenpol Weight & Balance
Brodhead -1994
CG
CG Wt. w/170# CGw/170#
w/170# pilot
Tail Engine Fuselage Empty empty / pilot
pilot
Number Type Length Weight inches & 170# pass & 170# pass
& 7 gal.
aft of datum & 7 gal. fuel & 7 gal. fuel
fuel
Ford
N444MH Short 648 7.49 17.72 1048 18.83
'A'
Ford
NX13691 Short 676 11,83 2L04 1088 22,02
'A'
Ford
NX4662T Short 671 13.69 20.45 1071 20.7
'A'
Ford
NX5228 Long 684 6.69 16.16 1084 17,33
'A'
C FCMG 0-200 Long 774 15.25 20.42 1208 19.43
N396S j¡ C-85 Long j¡ 820 15.2 ¡| 18.61 1256 [ 16.57
N687MB 0-200 Long 705 5.59 14.57 1143 15.79
N 778DD Corvair Long 731 9.08 15.93 1191 14.98
