WACO AIRCRAFT COMPANY
MODELS: Waco YKS-7 (Army UC-72K) and ZKS-7 (Army UC-72M)
T.C. NUMBER: 626
I - SPECIFICATIONS PERTINENT TO ALL MODELS:
Propeller Maximum permissible diameter 107 inches (for clearance)
Placard speeds Level flight or climb - 140 mph True Ind.
Glide or dive - 168 mph True Ind.
Fuel capacity 70 gallons (two 35 gallon tanks in upper wings) (-11. 5)
Oil capacity 5 gallons (-44)
No. passengers 4 (1 at -2.5, 3 at +27) (crew at -2.5)
Baggage 100 lbs. (+45)
Standard weight Landplane 3250 lbs.
Seaplane 3540 lbs .
C.G. limits Landplane (-14.4) and (-2.5)
Seaplane (-12.9) and (-3.7)
Datum Lower wing leading edge
Leveling means Lower surface upper wing at strut points
Certification basis Type Certificate No. 626 (Aero. Bulletin 7A)
Production basis None (See NOTE A)
Serial numbers 4551 and up per NOTE A and all AAF numbers of Models
UC-72K and UC-72M. Use manufacturer's number when
available.
EQUIPMENT:
(* Means net increase)
Class I:
Landplane:
101. Engine ring cowl 27 lbs.
102. Starter (Eclipse E-80) 20 lbs. (-51)
103. Generator
(a) Bosch LE70/12) (YKS-7) (See NOTE 3) 13 lbs. (-54)
(b) Eclipse LV-180 (ZKS-7) (See NOTE 3) 18 lbs. (-54)
104. Battery (Reading ARL-11) 35 lbs. (-44)
105. 7.50-10 wheels (Hayes 150M) with
8.50-10 tires
106. 10x3 tail wheel
107. Oil cooler
108. Wheel cuffs
109. Rocoteen upholstering
110. Gunmetal gray paint
111. Propeller - wood (fixed pitch) including
hub
(a) Model YKS-7 42 lbs.
(b) Model ZKS-7 46 lbs.
Seaplane: (Items 101, 102, 103, 104, 107, 109, 110 and 111 PLUS)
151. Edo model 38-3430 floats with
water rudders
and
152. Seaplane type vertical surfaces
replacing landplane type 335 lbs.*
Class II:
200. Miscellaneous items as noted in
approved weight and balance report.
201. Large starter (Eclipse F-141) 10 lbs.* (-53)
202. Large generator
(a) Eclipse D-2
(YKS-7) 13 lbs.* (-54)
(ZKS-7) 8 lbs.*
(b) Eclipse LV-180 (YKS-7) 5 lbs.*
(c) Eclipse G-2
(YKS-7) 8 lbs.* (-54)
(ZKS-7) 3 lbs.* (-54)
203. Pressure fire extinguisher (-36) or (+12)
204. Oil heater 3 lbs.
205. Leather upholstering 5 lbs. to 12 lbs.* (+7)
206. Litter installation 25 lbs.* (+97)
207. 100 gallon fuel capacity (two 15
gallon tanks in lower wings) and
6-1/2 gallon oi1 capacity 35 lbs.*
208. Propeller - Hamilton Standard
adjustable metal
(a) YKS-7 36 lbs.* (-79)
(b) ZKS-7 32 lbs.* (-79)
209. Rear parachutes or parachute type seats
210. Large battery (Exide) 7 lbs.* (-44)
211. Propeller -
(a) (YKS-7) Hamilton Standard hub 2B20,
blades 6109A-6 to 6109A-16, inclu-
sive, or 6135A-6 to 6135A-16,
inclusive. Diameter 8'6" maximum,
7'7" minimum. 104 lbs.
Class III:
301. Wheel streamlines 21 lbs. (-24)
302. Cactus proof tubes 10 lbs.* (-28)
303. "Y" type control column (inspector
should specify type installed) 3 lbs.* (-24)
304. Miscellaneous extra instruments and
panel 25 lbs. (-34)
305. Propeller - fixed pitch metal
(Curtiss 55501)
(a) YKS-7 9 lbs.* (-79)
(b) ZKS-7 5 lbs.* (-79)
306. Flares
(a) Three 1-1/2 minute 17 lbs. (+70)
(b) Five 1 minute 13 lbs. (+70)
307. Landing lights (Grimes retractable) 11 lbs. (+7)
308. Engine shielding 11 lbs. (-75)
309. Radio (under rear passenger seat) 52 lbs. (+27)
310. Extra door and wing walk 16 lbs.* (+19)
311. Special paint Maximum 44 lbs.* (+27)
312. Tail wheel lock Neglect increase
313. Cabin ventilators 3 lbs.*
314. Cabin heater 5 lbs.* (-51)
315. Soundproofing
316. Air brakes 10 lbs.*
317. (a) Jacobs L-4M engines installation
(magneto ignition) (YKS-7) 15 lbs.*
(b) Jacobs L-4MB engine installation
(magneto and battery ignition)
(YKS-7) 8 lbs.*
(c) Jacobs L-6M engine installation
(magneto ignition) (ZKS-7) 15 lbs.*
(d) Jacobs L-5MB engine installation
(magneto and battery ignition)
(ZKS-7) 8 lbs.*
318. Front parachutes or parachute type seats
319. Wide type landing gear - tread
103-1/2 inches No Weight change
320. Revised engine cowl (Drawing 21987)
321. Revised windshield
322. Steerable tail wheel (Drawing 23143) Neglect wheel increase
323. Skis (Use actual weight)
(a) Grab and Smith GS- 1
(b) Federal SC- 6
NOTE A. Each aircraft of Models YKS-7 and ZKS-7 manufactured after 4/13/43,
must, prior to original certification, satisfactorily pass:
(a) An inspection for workmanship, materials and conformity before any
covering, metal priming or final finish is applied. All woodwork
may be varnished.
(b) A final inspection of the completed aircraft.
(c) A check of the flight characteristics.
NOTE 1. Same as YKS-6 or ZKS-6 (ATC 533) except wing fittings, landing gear
moved forward 4 inches, fixed trim tab added to rudder, miscellaneous
changes in fuselage and controls.
NOTE 2. Eligible for export as follows subject to inspection for equipment
specified in Chapter XII of Inspection Handbook:
(a) Canada
- Landplane
- Skiplane - not eligible. However, structure complies with
Canadian requirements, for ski installation when equipped with
special axle per Waco Drawing No. 20243 and tread with skis is
equivalent to that with wheels. Maximum ski height 13 inches.
- Seaplane - maximum standard weight 3430 lbs.
(b) All other countries except Australia and New Zealand.
NOTE 3. Item 103(a) or (b) may be removed when item 317(a) or (c) is installed.
II - MODEL YKS-7 (UC-72K), DESIGNATION 5 KL-SB
Engine Jacobs L-4
Placard limits For all operations, 2000 rpm (225 hp)
III - MODEL ZKS-7 (ARMY UC-72M), DESIGNATION 5 RCL-SB
(Same as YKS-7 except engine. Empty weight approximately 35 lbs. greater than
YKS-7.)
Engine Jacobs L- S
Placard limits Take-off and climb
2000 rpm (285 hp)
For all other operations
1910 rpm (250 hp)