Jetranger Ii Vs Jetranger Iii

[Coastal]

Hi folks,

 

Trying to remember the differences between a JRII and a JRIII, as far as limitations go. TOT max. cont in a JRII is 737 vs. 738 in a JRIII I believe. There are a couple other small differences as well aren't there?

 

Bigger tailrotor in the JRIII, also a bigger engine? What is that, a C20B vs a C20J?

 

Fire away, thanks for your help.

 

Happy New Year to all.

 

Coastal

[3BX2]

From what I remember... ( and this crowd will correct my mistakes )

 

Max TOT is different. 795 vs 810 (??)

TR diameter can be different ( 65" vs 62").

TR drive shaft is probably different, Larger TR needs the segmented shaft (??)

TRGB output shaft is different, (tapered)

Engine is 250C20B or J vs 250 C20

 

Not much In-Flight differences below 8,000, much better TR authority and TOT above that altitude.

[skidkicker]

the airframe is usually heavier in a b3 vs the b2.

[ray]

TOT is 795 and 810.

 

Segmented shaft was introduced around serial number 1250, so it was still a Jetranger II.

 

Oil cooler blower is bigger on a III, the oil lines are a larger diameter.

 

The oil cooler deck is composite on a III, aluminum on a II. (The composite has a drain pan under the cooler, the aluminum one is open into the heater deck. You need to know that when washing the oil cooler blower.)

 

T/R gearbox is a different number on a III with a much thicker output shaft.

 

Different servo mounts between the two.

 

The III's have 'slam doors'. DON'T slam them.

 

Location of fresh air vents is different on nose.

[Coastal]

Alright, so as far as limitations go, is the only difference between the two reflected in TOT?

 

JRII: Max Cont: 737; Max T/O: 795

JRIII: Max Cont: 738; Max T/O: 810

 

I thought there was some slight variation in max N1 as well, 105% vs 106% max.

 

Thanks again.

 

Coastal

 

[skullcap]

unless fm tot limit has changed the max on JRII is 793 not 795 compared to 810 on JRIII

 

N1 limit - 104 vs 105

NR limit - 95 to 100 vs 97 to 100 power on

 

I seem to remember a change in c of g limits doors off on JRIII but have no fm.

 

 

 

[ame206350]

TOT is 795 and 810.

 

Segmented shaft was introduced around serial number 1250, so it was still a Jetranger II.

 

Oil cooler blower is bigger on a III, the oil lines are a larger diameter.

 

The oil cooler deck is composite on a III, aluminum on a II. (The composite has a drain pan under the cooler, the aluminum one is open into the heater deck. You need to know that when washing the oil cooler blower.)

 

T/R gearbox is a different number on a III with a much thicker output shaft.

 

Different servo mounts between the two.

 

The III's have 'slam doors'. DON'T slam them.

 

Location of fresh air vents is different on nose.

 

There were rotorhead and freewheel changes too but I can't recall the serial number break.....may have actually been in later B2's like the segmented shaft and blower. Of course all B2 post SI-112 have some of this crap too so quite a bit of overlap between the B2 and B3 mechanically.

[Hazy]

There were rotorhead and freewheel changes too but I can't recall the serial number break.....may have actually been in later B2's like the segmented shaft and blower. Of course all B2 post SI-112 have some of this crap too so quite a bit of overlap between the B2 and B3 mechanically.

 

 

and for reading pleasure, "INFORMATION LETTER 206-04-89" which uses SI-112 for the Gross Internal Increase STC.

[RatDog]

difference in N2 limits

JR11 95-100

JR111 97-100

[launchpad mcquack]

Minimum Pilot weight:

150 lbs. JRII

170 lbs. JRIII

JR II: Heater and defroster off for take-off, landing and hover.

JR III: Heater and defroster as required.