Structural Sub-Component Weight Groups Parametric Plots
The
plots below show
some of the
preliminary parametrics for the sub-component weights that sum to the
Overarching Structural Group weight that have been developed from the
data
available for single engine monoplane WWII era aircraft discussed on
this website.
Caveats
Please
note
that;
- Currently
everything is still
very much a work in progress and subject to further refinement and
revision as I work to verify the data that I have currently transcribed
from the references, and as I work to collect dimensional and powering
data on the specific aircraft that I have weight data for.
- All weight
units are in pounds and power units are in Horsepower.
- For some
weight groups (such as the "Tail" group or the
"Landing Gear" group, a further subdivions of weights may be provided
for those airplanes where such data was available. As such,
rows
below the "Tail" group for the "H Tail" (Horizontal Tail) and "V Tail"
(Vertical Tail) are included for some aircraft. Similarly
rows
below the "Landing Gear" group for "Main LG" and "Tail/Nose Aux LG"
have also been added, though I may eventually separate the "Tail/Nose
Aux LG" row into a separate "Nose Aux LG" and "Tail Aux LG" row to make
it easier to differentiate these weights on the parametric plots being
developed.
- It
currently is unclear what all is included in the "Engine Section"
weight group. It appears that this includes the the engine
mounts
for allaircraft as well as cowling and cooling flaps for radial
engines. However for a few aircraft in the lists below such as the
XP-63A a very low value of 4lb is given, while for the P-63A-10 and
P-63C no value is given, leading to the suspicion that the weights of
the enine mount for those aircraft may be included elsewhere in the
weight estimate (such as in the "Fuselage" weight or "Engine
Accessories" weight groups.
- I need to
further review and
clean up the "Fuselage" and "Body" group weights to ensure that I have
correctly and consistantly recordedd this data. Specifically;
- In
Reference [1] many of the aircraft list "Fuselage" and "Engine Section"
weights separately. However for several of the F2A/B339
aircraft
variants a "Body + Landing Gear" weight and an "Engine Section" weight
is given, whereas for the XF2A-1 no separate "Engine Section" weight
appears to be given.
- In
Reference [2] only "Body" weights are listed, with no mention of
"Fuselage" or "Engine Section" weights.
- In
References [3] and [4] the "Body Group" weight is listed as including
the "Fuselage less Engine Section" and "Alighting Gear" (Landing Gear).
However, since weight data is provided for both the
"Fuselage less Engine Section" and "Alighting Gear" in addition to the
total "Body Group" weight it is fairly easy to re-align these weights
to match the format used in other references if necessary.
However, eventhough the "Fuselage less Engine Section" is
called
out as a weight group I cannot find anywhere in these references where
the "Engine Section" is accounted for. As such, I am
currently
still reviewing the weight from these two references and have not yet
incorporated them into the plots below.
- In
Reference [5] the "Body Group" weight and "Landing Gear" weights are
listed separately.
As such, it appears that the
most consistent use of terminology would be to;
- Treat the
"Body Group" as being the sum of the "Fuselage" and "Engine Section
Groups"
- Investigate
the weights of the "Alighting Gear" (Landing Gear) separately, where
possible
- Also
dosome analyses of "Body" weight plus "Landing Gear" weight to see how
the F2A/B339 variants listedin Reference [1] compare to the other
aircraft that there is data on.
Beyond this I also
intend to continue to review the information provided in References [3]
and [4].
Structural
Weight Sub-Components
As
noted on
the General Weight
Summary Format page,
the overarching Structural Weight Group is equal to
the sum of the;
- Alighting/Landing
Gear Group
The
first plot below show the relationship of Wing Wing to Total
Wing
Area. As shown in this plot a number of the naval aircraft
designs have folding wings.
I am currently working to try and
develop more detailed plots to better help identify the impact that
incorporating the ability to fold has on the overall weight of a wing.
In addition, in reviewing Wing Weight equations for other
aircraft type it can be seen that there are several other factors other
than just Wing Area which are expected to impact the overall wing
weight, including such factors as;
- Wing Area
- Weight of
Fuel Carried in the Wings
- Wing
Aspect Ratio
- Wing
Sweep Angle
- Wing
Taper Ratio
- Wing
Thickness to Chord Ratio
- Ultimate
Load Factor
- Aircraft
Design Gross Weight
- Dynamic
Pressure - which is a factor of the aircraft's speed
The next
three plots show som of the areas that I have been looking into with
respect to this. The first two graphs show a plot of the Total
Wing Weight of the designs being analyzed divided by the their Total
Wing Area (which includes the ailerons and flaps) versus Basic Gross
Mission Wt and Design Speed Limit, respectively. As
shown in these plots there is a trend of increasing Wing Wt/Square Foot
with increasing Basic Gross Mission Weight and Design Speed Limit,
which is a factor of the wings having to support more lift and them
experiencing more dynamic forces as both weight and speed increase.
Please
note that in the second plot above Design Speed Limit is not the
maximum speed that the plane could reach at full power,
but rather a maximum speed that is used during the design of an
aircraft to help determine the maximum forces and loads that the
structure will experience. Unfortunately, from data on the P-51D it
appears that this may notbe the same as the "Not To Exceed" or "Never
Exceed" Speed that is sometimes
listed for aircraft. Since I currently do not have data on
Design Speed
Limits or Not to Exceed Speed Limits for all the aircraft currently
being analyzed, I have also put together an additional plot of Wing
Weight/Square Foot versus the Rated Take-Off Power of the installed
engine on each plane the to see if that parameter could be used as a
stand in, since for these single engine monoplanes currently being
analyzed, as a plane with higher installed power will likely
have a higher top end speed,and as such would likely also have a higher
Design Speed or Do Not Exceed Speed.
These
plot represent an initial first step in the analyses of Wing Wt for
these aircraft and I hope to continue looking into Wing Wt in the
future.
The
next three plots
show the
relationship of Total Tail Weight to Total Tail Area, Horizontal Tail
Weight to Horizontal Tail Area, and Vertical Tail Weight to Vertical
TailArea, respectively.
These
last few plots show "Body Group" weight versus both "Basic Mission
Gross Weight" and "Body Length". In reviewing the data
though, it
is not clear what the "Body Length" reported in Reference [2]
specifically relates to. Specifically for radial engined
aircraft
it looks like it may actually only address to length of the aircraft
aft of the fire wall, and not include the length of the cowling.
As such I intend to further review these values and may
eventually replace the plot below with a plot of "Body Weight" versus
"Total Aircraft Length". Also along these lines, since there
appears to be some degree of scatter in the plot of "Body" weight verse
"Body Length" I may look to trying to also incorporate "Body Width"and
"Body Depth" into the analyses since the weight of a very deep fuselage
or a very narrow fuselage may be expected to vary a fair bit from other
aircraft of similar lengths.
The
next three plots show the Total Landing Gear Weight, the Main Landing
Gear Weight, and the Nose/Tail Landing Gear Weight as a function of the
Basic Mission Gross Weight of the aircraft analysed.
Notes:
This website
has been developed with a number of low cost or free programs including
Hot Metal Pro, KompoZer, Microsoft Designer and Da Button Factory.com
Rev 2-18-25
