Thorp Air Command - T18.net

does anyone have a weight and balance worksheet for the T-18? I have searched the site but not having much luck. thanks. Also finished my interior today!!!!

Here is what I have in my POH, I have the Trusty tail spring and wheel. Note, my main gear locations are not equal, after 45 years there have probably been some hard landings in there somewhere. The last time I weighed my aircraft I measured the axle locations using the wing leading edge (STA 55.0) as the reference.
NOTE: the formatting did not follow (cut & paste).

EMPTY WEIGHT CG CALCULATION

Aircraft weighed in level flight attitude with zero usable fuel, oil (6.0 qts in sump)

Scale Readings Weight Arm Moment
Left Main 430 53.125 22843.75
Right Main 447 53.3125 23830.69
Tail 55 223.375 12285.63
Empty Weight 932 58960.07

CG = 58960.07/ 932.0 = 63.26

LOADING WORKSHEET

EMPTY WEIGH 932.0 63.26 58960.07

Pilot Seat _____ 86 ______

Co-Pilot Seat _____ 86 ______

Fuel (Full = 168 Lbs) _____ 50 ______

Baggage _____ 109 ______

Total _____ ______

CG =Total Moment / Total Weight
CG = _________ in aft of datum

C.G. RANGE - 15% TO 34% OF WING CHORD
STATION 62.5 TO 72.0
7.5" TO 17" FROM WING LEADING EDGE

_________________
Bruce Finney
N18JF T-18C #262
Yelm, WA USA

This is what I use... The first one is the basic blank form for my airplane. The second one is a representative sample with me (180#), a passenger (170#), 9# of "stuff" under the passenger seat (tie-down kit, canopy cover, etc.), and 99# of baggage (19# of which is a tool kit, survival kit, etc.) - I carry the stuff under the seat & the 19# in the baggage compartment pretty much all the time. The most aft CG condition is calculated with 5 gals. of fuel remaining in the tank. My empty weight at the last weighing was 940# (weighed with 8 qts. of oil).

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John Evens
Arvada, Colorado
T-18 N71JE (sold)
Kitfox 7 SS N27JE

John, I have always wanted a Thorp specific W&B Sheet. Thanks for sharing.

I have been using an android app ((free) by yeno, available at the playstore).. its simple. Just enter your empty and gross weights along with most forward and aft cg locs...then add stations for fuel, people and baggage and the app tells you takeoff and landing cg of g and weights. Beats the he77 out of doing the paperwork each time. The app even warns you based on fuel load and burn whether you will be short fuel (30 minute reserve) or out of c of g range based on start and ending fuel... pretty cool stuff for free.

just my Canadian 2 cents... that's about 1c USD

Tim,

That sounds like a cool program, and the price is right!

FWIW, I don't have to run the numbers every time I load the airplane up. I filled-in copies of my form with a few hypothetical situations, and it's easy to know if you're with the limits or not, just knowing what your passenger & baggage weights are. For instance, I can carry a 259# passenger & no additional baggage (just the19# that are there already), and be at 1600# & be within my CG limits with a comfortable margin from most forward (full fuel) to most aft (5 gals. fuel). If I wanted to fly at 1650# and accept even lower G limits, I could carry a 264# passenger & 45# of additional baggage & stay between my CG limits, but I don't do that. So I could easily carry a 300# passenger without baggage (if he/she could fit and not break the seat ). I'm very conservative with fuel, so I am very unlikely to reach those most aft CG conditions. I've flown the airplane at my hard aft limit (32% of chord or 16" aft of the leading edge), but I don't like the way it feels, and I stay plenty away from that - there's no reason not to. The airplane will safely carry a real load without pushing it, as most everyone on this list knows.

_________________
John Evens
Arvada, Colorado
T-18 N71JE (sold)
Kitfox 7 SS N27JE

Exactly John, the wife and I, baggage at 70lbs, 5 gal of fuel my CG goes aft limit. have never got it to this point but I notice at 10gal with the above numbers the tail feels a bit glitchy on landings, a bit heavy so to speak. Battery is behind passenger seat, could have put it on the firewall....Dan

Scott, very nice job on the Cockpit upholstery, that is clean and neat......Dan