NASA 

Tech n ica I 

Paper 

291 1 

AVSCOM 

Tech n ica I 

Report 

89-C-010 

1989 

National Aeronautics and 

Space Administration 

Office of Management 

Scientific and Technical 

Information Division 

Comparison of Predicted 

and Measured Temperatures 

of UH-60A Helicopter 

Transmission 

Harold H. Coe 

Lewis Research Center 

Cleveland, Ohio 
Summary 

The 2109-kW (2828-hp) UH-60A Black Hawk helicopter 

transmission was one of the transmissions used to obtain an 

experimental data base. Component improvements or new 

transmission concepts can thus be evaluated by comparison 

with the established data. Results of efficiency and vibration 

tests of the UHdOA have been reported previously. In this 

investigation the transmission was instrumented internally and 

tested over a range of operating conditions. The speed was 

varied from 50 to 100 percent of the full rated value, and the 

torque was varied from 10 to 100 percent of the full rated 

value. Temperatures of internal bearings and gears were 

measured. The computer program Planetsys was used to 

simulate the thermal performance of this transmission. The 

calculated temperatures were then compared with the corresponding measured values. The highest measured temperature 

was 405 K (270 OF) on the outer ring of the high-speed input 

shaft roller bearing, at the 100-percent power condition. In 

general, the predicted temperatures compared very well with 

the measured values, most of them being within 5 kelvin 

(9 deg F). Specifically, the temperatures predicted for the 

single-row spherical roller planetary bearing averaged only 

about 4 kelvin (8 deg F) lower than the highest measured 

value. 

Introduction 

Because of their versatility helicopters have become an 

important segment of the aircraft industry, for both civil and 

military applications. A critical component of any helicopter 

is the transmission required to reduce the turbine engine speed 

to the main rotor and tail rotor speeds. Transmissions used in 

aeropropulsion systems, however, can have severe limitations 

such as low durability, reliability, and maintainability or high 

noise, vibration, and weight. The transmission research 

programs conducted at the NASA Lewis Research Center over 

the past few years are outlined in reference 1. In general, these 

programs were aimed at extending the life of a transmission, 

improving its reliability, reducing the required weight, or 

reducing the noise and vibration. So that improvements in 

components or new transmission concepts could be evaluated, 

however, it was important to establish a base of data on what 

I 

were then current state-of-the-art transmissions (ref. 2). One 

of the transmissions chosen was the UH-60A Black Hawk, 

a 2 109-kW (2828-hp), dual-input, planetary helicopter 

transmission. 

Efficiency and vibration tests conducted previously on the 

UH-60A are reported in reference 3. After these tests (which 

required only external instrumentation) were run, the transmission was further instrumented internally and additional data 

were obtained. Gear tooth stress measurements were made 

first, to utilize new strain gages before they became damaged 

(ref. 4). 

It is equally important to obtain thermal measurements 

for the transmission, not only for evaluation of possible 

improvements, but also as a means of validating computer 

programs (such as Planetsys, ref. 5) that predict these operating 

characteristics, since this type of data is not readily available 

(ref. 2). The objects of this investigation were therefore to 

obtain temperature data on the internal bearings and gears of 

this UH-60A transmission over a range of operating conditions 

and to compare the results with values predicted by the 

computer program Planetsys. The transmission was operated 

from 10 to 100 percent of full rated power with rotor speeds 

from 50 to 100 percent of the full rated value. The inlet oil 

was maintained at 355 K (180 OF). 

Apparatus 

Test Transmission 

The UH-60A helicopter transmission has a dual input power 

rating of 2109 kW (2828 hp). It provides a total speed 

reduction of 81.042: 1 in three stages from the engine input 

(20 900 rpm) to the main rotor output (258 rpm). There is 

also a tail shaft output (4117 rpm). 

The transmission, more fully described in reference 3, is 

shown in figures 1 and 2. It consists of two input modules 

and one main module. The input modules contain the first 

reduction stage, which then drives an intermediate-speed shaft 

through an overrunning ramp-roller clutch. The second 

reduction stage, in the main module, combines the two inputs 

and drives the sun gear of the planetary third stage. The 

planetary system has five planet gears and a fixed ring gear. 

The planetary carrier output then directly drives the main rotor 

shaft. Also shown in figure 2 are the locations of the 
Figure 1 .-UH-60A Black Hawk transmission. 

1,f 

INPUT MODULE (ONE OF TWO) MAIN MODULE 

INTERMEDIATE-SPEED SHAFT 7, 

TAIL TAKEOFF 

AGNESIUM HOUSING 

BEARING 2- 

\HIGH-SPEED INPUT 

I i~ 

I ‘-CANTILEVER PLANETARY 11 THERMOCOUPLE 

AAND B 

LUBRICATION PUMP’ 1 

LBEVEL PINION, TOE 

Figure 2.-Cross section of UH-60A transmission, showing location of thermocouples. 

ORIGINAL PAGE 

BLACK AND WHITE PHOTOGRAPH 
thermocouples used to obtain the temperature data. Shaft 

speeds and numbers of gear teeth are shown in table I. 

The spherical roller bearings used in the planetary had a 

110-mm bore diameter and a 170-mm outer diameter, with 

a single row of 18 rollers, each 19.5 mm in diameter and 

29.5 mm long. The pitch diameter was about 140 mm. The 

bearing is shown in figure 3, and more complete specifications 

are given in table 11. 

I 

1 

TABLE 1.-SHAFT SPEEDS OF UH-60A 

TRANSMISSION AT 100-PERCENT 

ROTOR SPEED (258 rpm) 

Gear component 

Spiral bevel input pinion 

Spiral bevel input gear 

Combining bevel pinion 

Main bevel gear (lower) 

Sun gear 

Planet gears (five) 

Carrier (output) 

Ring gear 

Main bevel gear (upper) 

rail output gear 

Number of 

teeth 

22 

80 

17 

81 

62 

83 

228 

116 

34 

___ 

aPlanet gear rotates at 709 rpm with respect to carrier 

Shaft speed, 

1 207 

4 117 

TABLE 11.-PLANET ROLLER BEARING SPECIFICATIONS 

Outer diameter, mm (in.) 

Bore diameter, mm (in.) 

Pitch diameter, mm (in.) 

Roller maximum diameter, 

Roller length, mm (in.) . 

Roller crown radius, mm (in.) .................... 78.23 (3.080) 

Number of rollers ...... 18 

Cage type ..................................... One-piece machined 

Cage guide .......................................... Inner-ring land 

Bearing diametral clearance, mm (in.): 

Outer-ring groove radius, ............. 79.75 (3.140) 

Unmounted ....................................... 0.1727 (0.0068) 

Mounted.. ......................................... 0.08 13 (0.0032) 

Test Facility and Instrumentation 

The NASA Lewis 2200-kW (3000-hp) Helicopter 

Transmission Test Facility, shown in figure 4 and more fully 

described in reference 3, is a recirculating-power (four square) 

type. Power, provided by a constant-speed, 600-kW induction 

motor, flows through the two inputs to the test transmission 

and the two outputs (main rotor and tail drive). Since power 

flow is recirculating, only frictional losses need to be 

replenished by the motor. Speed control is accomplished by 

an eddy current clutch. Torque is induced independently in 

each loop by planetary torque units. 

Figure 3.-Planetary gear and single-row spherical roller bearing. 

ORIGINAL PAGE - 

BLACK AND WHITE PHOTOGRAPH 3 
C-83-5298 

Figure 4.-NASA Lewis Helicopter Transmission Test Facility. 

Type K (Chromel-Alumel) thermocouples were placed at 

the locations shown in figure 2. The thermocouples used to 

measure bearing temperatures were tight against the steel liners 

separating the outer rings from the magnesium housings. Those 

thermocouples measuring the temperatures of the oil exiting 

the gears (referred to as oil flingoff thermocouples) were 

housed in a special cylinder facing the oil stream, as shown 

in figure 5. The signals from the thermocouples located on 

the moving shafts were fed out of the transmission through 

four slipring assemblies. One slipring was mounted on each 

of the two input modules and transmitted data from the 

intermediate-speed shaft. A third slipring was mounted on the 

main module and transmitted data from the main output shaft 

and planetary carrier. The fourth assembly, an internal slipring 

mounted inside the main module above the combining bevel 

gear, transmitted data from the sun gear. 

Procedure 

The testing consisted of varying the shaft speed or the torque 

as required to achieve the matrix of test points indicated in 

table 111. With the speeds ranging from 50 to 100 percent of 

the full rated value, and the torques from 10 to 100 percent, 

the resulting power ratings ranged from 10 to 100 percent. 

For each data point the specified speed and torque were set 

and the transmission was operated at that setting until all 

temperatures had reached equilibrium, at which time the data 

achieved when no temperature had changed more than 1 kelvin 

(2 deg F) in 10 min. The oil inlet temperature was maintained 

constant at 355 K (180 OF) for all tests. Also, for each test 

the tail torque was set so that about 15 percent of the 

transmitted power flowed through the tail drive loop. 

, 

were recorded. Quilibrium was assumed to have been 1 

4 

ORIGINAL PAGE 

BLACK AND WHITE PHOTOGRAPH 
I 

ORlGiNAL PAGE 

BLACK AND WHITE PHOTOGRAPH 

I 

(a) As placed in special cylinder. 

@) As mounted on carrier. 

Figure 5.-Oil flingoff thermocouple. 

P Computer Program 

The computer program Planetsys (ref. 5 is the users manual) 

was used to predict the operating characteristics of the 

UH-60A Black Hawk transmission. Although this program 

had been used previously to simulate the operation of an 

OH-58 transmission (ref. 6), there was no experimental 

verification of the actual planetary bearing temperatures. 

Further, the OH-58 planetary referenced in that report used 

a double-row spherical roller bearing, and the UHdOA uses 

a single-row spherical roller bearing in its planetary. 

Planetsys was developed to simulate the thermomechanical 

performance of a multistage planetary power transmission. The 

major function of this program is to compute, for any of the 

six possible kinematic inversions for a planetary system, the 

performance characteristics of a planet bearing. This bearing 

can be either a cylindrical or a spherical roller bearing and 

can contain one or two rows of rollers. The outer ring can 

be rigid or flexible. 

5 
TABLE 111.-NOMINAL 

TEST POINTS 

10 1 

50 

Power, 

percent o 

full rated 

100 

75 

50 

25 

10 

75 

56.2 

37.5 

18.7 

50 

37.5 

25 

Planetsys is also capable of producing either steady-state 

or time-transient temperature maps of an axisymmetric 

mechanical system. This is accomplished by approximating 

the mechanical system by a number of simple geometric 

elements, each represented by a node point (ref. 5). Program 

input includes bearing geometry, bearing material and lubricant 

properties, and operating conditions (such as load, speed, and 

ambient temperature). When the program is used for thermal 

analysis, additional input is required, since all the thermal 

nodes must be defined. The maximum number of nodes 

permitted is 100. The nodal system used with Planetsys for 

the Black Hawk transmission is shown in figure 6. The 39 

air and metal nodes are shown in figure 6(a) and the 31 

lubricant nodes in figure 6(b). 

Results and Discussion 

The results of this investigation are presented in the 

following manner: 

(1) First, the experimentally determined temperatures are 

shown for the high-speed-shaft and intermediate-speed-shaft 

thermocouple locations. 

(2) Second, the steady-state thermal techniques that are used 

with the Planetsys computer program, including the heat 

transfer coefficients and constant heat inputs, are explained. 

(3) Third, the predicted and measured temperatures for 

corresponding locations on the planet bearing, the ring gear, 

the sun gear, the mast bearings, and the outside skin are 

compared. 

Measured Temperatures 

The temperatures as measured with the thermocouples 

located on the bearings on the left and right high-speed input 

shafts and on the left and right intermediate-speed shafts, plus 

the temperatures from the oil flingoff thermocouples at 

the high-speed gear mesh and the combining gear mesh 

(fig. 2), are shown in figure 7 for the 100-percent-shaft-speed 

condition. The highest measured temperature was 405 K 

(270 OF) for the outer ring of the high-speed roller bearing 

(bearing 2). As expected, the temperatures for the 

intermediate-speed shaft bearings were somewhat lower. The 

inner ring of the tapered roller bearing (bearing 7) was hotter 

than the outer ring over the range shown. Note that the oil 

flingoff temperatures showed the same general trend as the 

other temperatures. 

Temperatures measured at the same locations for the 

75-percent-shaft-speed condition are shown in figure 8. The 

values were generally slightly lower than those for 100-percent 

speed, but with the same general trends. The temperatures at 

both speeds were a slight function of torque, reflecting the 

change in the power loss in the gear mesh as the power 

transmitted through the mesh was changed. 

It is interesting to compare the measured gear temperatures 

with the corresponding oil flingoff temperatures, as shown in 

figures 7(c) and 8(c) for the bevel gear and in figure 9 for 

the sun gear. The reasonably good correlation means that one 

can monitor gear temperatures without having a thermocouple 

right on the gear. 

Thermal Analysis 

Using the thermal analysis routines in the Planetsys computer 

program requires a definition of each nodal area, the type of 

heat transfer between nodes, and the corresponding heat 

transfer coefficient. The conduction heat transfer indexes are 

given in table IV, the convection indexes in table V, and the 

oil flow indexes in table VI. Some of the conduction indexes 

were derived for parallel or series heat flow through different 

materials, as described in reference 5. The convection indexes 

are also based on the equations presented in reference 5. 

The flow indexes are the product of the estimated oil volume 

flow rate times a specific heat of 2175 W sedkg "C 

(0.52 Btu/lb OF) times a density of 900 kg/m3 (56 lb/ft3). 

The total oil flow rate was measured. 

The thermal routines also permit input of known values of 

temperature and constant generated heat. Thus, the oil inlet 

node (node 69, fig. 6) was set to 355 K (180 OF) and the 

ambient air node (node 70, fig. 6) to 300 K (80 OF). The 

constant generated heat values are shown in table VU. These 

include those for the mast and sun shaft support bearings, the 

sun shaft bevel gear meshes, and the planetary gear meshes. 

The heat generation for the support bearings was estimated 

from data for similar bearings. For each gear mesh it was 

assumed that one-half of the heat generated went into each 

gear. And, in each case it was assumed that the heat generated 

at the mesh was 0.25 percent of the power being transmitted. 

Note that the value for the planet gear node (node 20, fig. 6(a)) 

is for a single planet, whereas the values for the sun and ring 

gear nodes (nodes 8 and 26, fig. 6(a)) are the total for all 

planets. 

6 
30- 

29-. 

32; Mast 

bearing 

housing28. 

70;Air 

(a) Metal and air nodes. 

(b) Oil nodes and flow paths. 

Figure 6.-Nodal system for UH-60A used with Planetsys. 
405 

385 

+ LeR bearing 1, outer rirg 

* Left bearing 2, outer ring Left bearing 3, wter ring 

- 0- - Left oil flngoff 

365 

- 

4 Right bearing 1, wter ring 

Right bearing 2. wter ring 

Right bearing 3. outer ring 

Rlght oil flingoff * - 0 - * 

160 L(b) I I I I I 

20 40 60 80 100 0 

+ -0- Left bearing 7, inner ring 

+ Left bearing 7. outer ring Left bearing 8, outer ring 

Left bevel gear, toe 

- Q- - Left oil flhgoff 

* Right bearing 7, inner ring 

* Right bearing 7. outer ring Right bearing 8, outer ring - - 0- * Right oil flingoff 

input torque. percent of full rated 

(a) Left high-speed input shaft. 

(b) Right high-speed input shaft. 

(c) Left intermediate-speed shaft. 

(d) Right intermediate-speed shaft 

Figure 7.-Measured temperatures of UH-60A transmission as function of input torque for 100 percent of full rated speed. 

8 
405 

385 

365 

Y 

g 

z 

405 

385 

365 

--O- Left bearing 1, outer ring 

-- Left bearing 2, outer ring 

-&- Left bearing 3. outer ring 

- -0 - Left oil fllncloff 

- 240 

* -0- Right bearing 1, outer ring 

* Right bearing 2. wter ring Right bearing 3. wter rina 

-0- . Right oil flingoff " 

- - 0- - - - - -0 ~ _--- -0- - 

I (b) 160 

20 40 60 80 100 0 

& * Left bearing 7, inner ring 

& 

Left bearing 7, outer ring 

Left bearing 8. outer ring 

--O- Len bevel gear, toe 

- -'+ - Left oil flingoff 

r 

6 Right bearing 7, inner ring 

Right beating 7, outer ring 

- * Right bearing 8. outer ring 

- -0 - Rightoilflingoff 

0 20 40 60 80 100 

Input torque, percent of full rated 

(a) Left high-speed input shaft. 

(b) Right high-speed input shaft. 

(c) Left intermediate-speed shaft. 

(d) Right intermediate-speed shaft 

Figure 8.-Measured temperatures of UH-60A transmission as function of input torque for 75 percent of full rated speed. 

t 

9 
Node 

(fig. 6) 

4 

5 

8 

12 

17 

18 

20 

26 

Description 

Lower mast bearings 

Upper mast bearing 

Sun gear 

Upper sun shaft bearing 

Combining bevel gear 

Lower sun shaft bearing 

Planetary gear 

Ring gear 

21 

22 

23 

24 

25 

26 

27 

28 

Bearing to oil 

Bearing to air 

Mast shaft; bearings to air 

Sun shaft; bearings to air 

Bevel gear to air 

Carrier; inside walls to air 

Housing to outside air 

Case bottom to outside air 

Flow patha 

I 

I1 

I11 

IV 

V 

VI 

VI1 

VI11 

Description 

Upper mast shaft bearing; sun gear 

Upper sun shaft bearings; bevel gear 

Lower mast bearing 

Lower sun shaft bearing; sun gear 

Sun gear 

Planet bearing (under ring) 

Bevel gear 

Total to all planet bearings 

TABLE VI].-CONSTANT HEAT 

GENERATION INPUT - o Sungear 

0 oil Flingoff 

Open symbols denote 100 percent of 

Solid symbols denote 75 percent of 

full rated speed 

full rated speed 

385 

Y 

i 

E 

- $ 365 a 

l34: 

Value assignec 

to node,a 

W 

75 

37 

2242 

20 1 

3032 

403 

897 

2242 

0 20 40 60 80 100 

Input torque, percent of full rated 

Figure 9.-Comparison of UH-60A transmission sun gear and oil flingoff 

temperatures. Speed, 75 and 100 percent of full rated. a~t 100-percent power 

TABLE 1V.-CONDUCTION HEAT 

TRANSFER INDEXES Comparison of Predicted and Measured Values 

Calculations were then made by using the Planetsys program 

and the aforementioned input data for both the 100- and 

75-percent-speed test points as shown in table III. The resulting 

predicted temperatures are compared in figures 10 to 12, with 

values indicated by the thermocouple located near the 

corresponding node. In figure 10(a) the planetary bearing 

inner-ring temperatures are compared with predicted values 

for the inner ring and planet post (nodes 24 and 25, fig. 6(a)) 

- 

Index Description Value, 

Wlm "C 

Bearings (steel) 

Shafts and gears (steel) 

Housing (magnesium) 

Carrier (titanium) 

Shaft to carrier (radial) 

Shaft to carrier (axial) 

Ring gear to lower case 

Planet post to inner ring 

Sun bearing to upper shelf 

45.0 

38.0 

85.0 

9.0 

13.6 

19.3 

68.9 

15.7 

78.4 - Node 24, inner ring - - - - 

0 

0 

A 

Node 25, post 

Planet A. inner ring at point of full load 

Planet A. inner ring at 90° from full load 

Planet 6. inner ring at point of full load 

- 240 - 

- 200 

L6 

-$- 160 a 

5 

E 

240 

I- 

- 200 

385 

365 

Y 

f 345 

5 

E 385 

L 

CL 

I365 

345 

TABLE V.-CONVECTION HEAT 

TRANSFER INDEXES 

U 

Index Description -3 _--- Value, 

W/m2 "C 

786.0 

32.7 

13.8 

46.5 

59.9 

20.2 

20.0 

7.0 

(a) I I I I I 

- 

- Node 24, Inner ring . - - - . 0 

0 

A 

Node 25. post 

Planet A, inner ring at point of full load 

Planet A, inner ring at 90" from full load 

Planet B. inner ring at point of full 

load 

TABLE VI.-FLUID FLOW INDEXES 

Value, 

WPC 

30.8 

61.6 

30.8 

61.6 

61.6 

246.2 

738.6 

- 

1046.4 

(b) I 

- 160 I I I I 

0 20 40 60 80 100 

Input torque, percent of full rated 

(a) 100 Percent of full rated speed. 

(b) 75 Percent of full rated speed. 

Figure 10.-Comparison of predicted and measured temperatures of UH-60A 

transmission planet bearing as function of input torque. 
(b) I I I I I 

305 

Y 

?- - 

f 365 

I- 

(d) I I I I I 

Node 24. inner ring 

Node 25, post 

Planet A, Inner ring at point of full load 

Planet A. inner ring at 90° from full load 

Planet E. inner ring at point of full load 

- 

--- 

0 

0 

A 9 

- 

P Y 

345 I 160- 0 20 40 60 80 100 

Input speed, percent of full rated 

Figure 11 .-Cornparison of predicted and measured temperatures of UH-60A 

transmission planet bearing as function of shaft speed for 100 percent of 

full rated torque. 

for the 100-percent-speed runs. Temperatures were measured 

on two planet bearings (A and B), at two locations. One 

thermocouple was placed at a point of maximum applied load, 

and the other was located 90" away. The predicted temperatures compared very well with the experimental data, having 

the same trends and averaging about 4 kelvin (8 deg F) lower 

240 r ::[ 

160 345 

Y P 

f 

m 

than the highest measured value. A similar comparison is made 

in figure 10(b) for the 75-percent-speed runs. The predicted 

values again compared very well with the measured 

temperature, being quite close at the higher torques and slightly 

high (about 2 kelvin; 4 deg F) at the lower torques. Finally, 

these same locations are compared in figure 11 as a function 

of speed for the 100-percent-torque condition. Again, the 

predicted temperatures compared very well. 

The predicted nodal temperatures can be compared with 

corresponding thermocouple data at a number of other 

locations, including the sun gear, the ring gear, the mast 

bearing outer ring, and the upper case outer skin. (The 

thermocouple locations are indicated in figure 2 and the nodes 

in figure 6.) These comparisons are shown in figure 12 for 

the 100-percent-speed condition. The predicted results 

generally compared very well with the measured values; the 

biggest difference was in the sun gear, where the predicted 

temperature (node 8) was 10 kelvin (18 deg F) higher than 

the measured value at the 100-percent-torque point (fig. 12(a)). 

Node 26 (fig. 12(b)) compared well with the measured ring 

gear temperature; node 27, which was predicted to be much 

cooler, was actually a flange of the ring gear sandwiched 

- 

. - - - Node 20. planet gear 

Node 8, sun gear 

- - Node62,sunoil 

0 Sun gear, inside 

0 Sun oil ff ingoff 

- Node 26, ring war 

- - Node 27, ring gear flange 

0 Ring gear, upper 

0 Ring gear, lower 

345 

.__L_______---------

0 P 0 11 0 0 

- Node 32, mast bearing housing 

Mast beanng E. outer ring 

Node 35, skin 

Node 15. upper case 

Skin. upper case at On 

Skin, upper case at w0 

-- 

0 

0 

Input torque, percent of full rated 

(a) Sun gear. 

(b) Ring gear. 

(c) Mast bearing. 

(d) Upper case skin 

Figure 12.-Comparison of predicted and measured temperatures of UH-60A transmission as function of input torque for 100 percent of full rated speed. 

li 
between the upper and lower cases, which were also much 

cooler (see upper case skin temperatures in fig. 12(d)). Note 

in figure 12(c) that the measured mast bearing outer ring 

temperatures fell nicely between the calculated values for the 

bearing center and the bearing housing. The calculated skin 

temperatures (fig. 12(d)) fell between the two measured values 

over the range of input torque. Both skin thermocouples were 

on the upper case; one thermocouple was located on the front 

side (opposite the tail takeoff), and the other was positioned 

90" away. 

Concluding Remarks 

Usually an important parameter in calculating rollingelement bearing operating characteristics is the amount of 

lubricant in the bearing cavity. Reference 6, however, notes 

that, because of the relatively low speeds of planetary bearings, 

the temperatures change very little when this quantity is varied 

over a wide range. Thus, for the present calculations the 

volume percentage of the bearing cavity that was occupied by 

the lubricant was kept at 2 percent for all cases. 

The predicted values of temperature generally compared 

well with the measured values, most of them being within 

5 kelvin (9 deg F). This was less than a 2-percent difference, 

based on absolute temperatures. It may therefore be stated that 

the computer program Planetsys can predict planetary bearing 

temperatures and other transmission component temperatures 

and that the assumptions made for the program were 

reasonably correct. 

Summary of Results 

The UH-60A Black Hawk helicopter transmission was 

internally instrumented and operated over a range of shaft 

speeds and input torques. Temperatures of the bearings and 

gears were measured. The computer program Planetsys was 

used to simulate the thermal performance of this transmission. 

The calculated temperatures were then compared with the 

corresponding measured vaiues. The following results were 

obtained: 

1. The highest measured temperature, 405 K (270 OF), was 

that of the outer ring of bearing 2, a roller bearing on the highspeed input shaft, at the 100-percent-power (2109 kW; 

2828 hp) condition. 

2. The oil flingoff temperatures correlated well enough with 

measured gear temperatures to suggest that gear temperatures 

can be monitored with this technique. 

3. The temperatures predicted for the single-row spherical 

roller bearing by the program Planetsys compared well with 

the measured temperatures, averaging about 4 kelvin (8 deg F) 

lower than the highest measured value. 

4. The Planetsys predicted values for the sun gear were about 

10 kelvin (18 deg F) high at the 100-percent power condition. 

Lewis Reserch Center 

National Aeronautics and Space Adsministration 

Cleveland, Ohio, February 2, 1989 

References 

1. Coy, J.J.; Townsend, D.P.; and Coe, H.H.: Results of NASA/Army 

Transmission Research. NASA/ARMY Rotorcraft Technology, Vol. 2, 

2. Zaretsky, E.V. : NASA Helicopter Transmission System Technology 

Program. Advanced Power Transmission Technology, G.K. Fischer, ed., 

3. Mitchell, A.M.; Oswald, F.B.; and Coe, H.H.: Testing of UH-60A 

Helicopter Transmission in NASA Lewis 2240-kW (3000-hp) Facility. 

4. Oswald, F.B.: Gear Tooth Stress Measurements on the UH-6OA Helicopter 

Transmission. NASA TP-2698, 1987. 

5. Hadden, G.B., et al.: Planetsys, A Computer Program for the Steady State 

and Transient Thermal Analysis of a Planetary Power Transmission 

System. (SKF-AT81DO44, SKF Industries, Inc.; NASA Contract 

6. Coe, H.H.: Thermal Analysis of a Planetary Transmission With Spherical 

Roller Bearings Operating After Complete Loss of Oil. NASA TP-2367, 

1984. 

NASA CP-2495-VOL-2, 1988, pp. 769-801. 

NASA CP-2210, AVRADCOM-TR-824-16, 1983, pp. 15-34. 

NASA TP-2626, 1986. 

NAS3-22690) NASA CR-165366, 1981. 

12 

I 
National Aeronautics and 

Space Administration 

Report Documentation Page 

NASA TP-2911 1. Report No. I 2. Government Accession No. 

AVSCOM TR 89-C-010 

4. Title and Subtitle 

Comparison of Predicted and Measured Temperatures of UH-60A 

Helicopter Transmission 

7. Author(s) 

Harold H. Coe 

9. Performing Organization Name and Address 

NASA Lewis Research Center 

Cleveland, Ohio 44135-3191 

and 

Propulsion Directorate 

U.S. Army Aviation Research and Technology Activity-AVSCOM 

Cleveland, Ohio 44135-3127 

12. Sponsoring Agency Name and Address 

National Aeronautics and Space Administration 

Washington, D.C. 20546-0001 

and 

U.S. Army Aviation Systems Command 

St. Louis, Mo. 63120-1798 

15. Supplementary Notes 

Harold H. Coe, NASA Lewis Research Center. 

3. Recipient's Catalog No. 

5. Report Date 

April 1989 

6. Performing Organization Code 

8. Performing Organization Report No. 

E-4588 

10. Work Unit No. 

505-63-5 1 

11. Contract or Grant No. 

13. Type of Report and Period Covered 

Technical Paper 

14. Sponsoring Agency Code 

16. Abstract 

The 2109-kW (2828-hp) UH-60A Black Hawk helicopter transmission was one of the transmissions used to 

obtain an experimental data base. Component improvements or new transmission concepts can thus be evaluated 

by comparison with the established data. Results of efficiency and vibration tests of the UH-60A have been 

reported previously. In this investigation the transmission was instrumented internally and tested over a range of 

operating conditions. The speed was varied from 50 to 100 percent of the full rated value, and the torque was 

varied from 10 to 100 percent of the full rated value. Temperatures of internal bearings and gears were 

measured. The computer program Planetsys was used to simulate the thermal performance of this transmission. 

The calculated temperatures were then compared with the corresponding measured values. The highest measured 

temperature was 405 K (270 OF) on the outer race of the high-speed input shaft roller bearing, at the 100-percent 

power condition. In general, the predicted temperatures compared very well with the measured values, most of 

them being within 5 kelvin (9 deg F). Specifically, the temperatures predicted for the single-row spherical roller 

planetary bearing averaged only about 4 kelvin (8 deg F) lower than the highest measured value. 

17. Key Words (Suggested by Author@)) 

Transmission; Helicopter; Temperature; Planetary; 

Computer program; Spherical roller bearing 

18. Distribution Statement 

Unclassified - Unlimited 

Subject Category 37 

9. Security Classif. (of this report) 20. Security Classif. (of this page) 121. No of 22. Price' 

Unclassified Unclassified 1 A03 

'For sale by the National Technical Information Service, Springfield, Virginia 221 61 NASA FORM 1626 OCT 86