Enstrom 480b

[helofixer]

Greetings from the bayous of Louisiana from a newbie to this forum. Recently a local police department here took delivery of a brand new Enstrom 480B (RR 250-C20 powered) helicopter. I have almost 20 years of Bell, Sikorsky, and MD experience and was wondering if any of you fellow wrenchers have worked on them and have any tips,general info, or heads up things to be looking out for? My first impression is that it is very different in general layout from what I am used to and while access to the engine is good, access to the main rotor gearbox and its belt drive leaves a lot to be desired. Thanks in advance.

[Paul]

Greetings from the bayous of Louisiana from a newbie to this forum. Recently a local police department here took delivery of a brand new Enstrom 480B (RR 250-C20 powered) helicopter. I have almost 20 years of Bell, Sikorsky, and MD experience and was wondering if any of you fellow wrenchers have worked on them and have any tips,general info, or heads up things to be looking out for? My first impression is that it is very different in general layout from what I am used to and while access to the engine is good, access to the main rotor gearbox and its belt drive leaves a lot to be desired. Thanks in advance.

Worked on them for 2 1/2 years, 5 years ago so some of this info might be old. Canopy is soft around the doors and the fwd lower engine panel watch this area. Belt alignment is critical for wear so stay on top of that. Engine speaks for itself, well versed, had no trouble there. Trany is alright short life but easy to change. All the rest of the components are standard helicopter components.

[Dewey]

It’s been over 30 years but here’s what I can add:

 

Rough ride issues with the articulated rotor system:

o Cyclic control looseness or binding in the rod ends

o

Play in firewall bellcranks

o Lower and upper swashplates for looseness or binding

o Ball bearings at swashplate connection of push pull rods going up the mast

o Binding, play, notchiness or grabbing the upper end of the push rods connected to the walking beam above the hub

o Walking beam center pivot point – smoothness of needle bearings and spacer sleeve. Verify torque.

o Lamiflex bearing separation. Disconnect the pitch link and flex grip in a 20° arc. The grip should return to the neutral position.

o Main rotor damper bleeding and rod ends for looseness

o

Guide tube DU bushings worn worn in excess of 0.010 inch

 

Ground resonance

o Oleo strut attachment hardware torque

o Oleo strut pressure

 

Hope this helps. Fly safe.

[RedRag]

It’s been over 30 years but here’s what I can add:

 

Rough ride issues with the articulated rotor system:

o Cyclic control looseness or binding in the rod ends

o

Play in firewall bellcranks

o Lower and upper swashplates for looseness or binding

o Ball bearings at swashplate connection of push pull rods going up the mast

o Binding, play, notchiness or grabbing the upper end of the push rods connected to the walking beam above the hub

o Walking beam center pivot point – smoothness of needle bearings and spacer sleeve. Verify torque.

o Lamiflex bearing separation. Disconnect the pitch link and flex grip in a 20° arc. The grip should return to the neutral position.

o Main rotor damper bleeding and rod ends for looseness

o

Guide tube DU bushings worn worn in excess of 0.010 inch

 

Ground resonance

o Oleo strut attachment hardware torque

 

 

 

 

o Oleo strut pressure

 

 

First time I worked on one I couldn't find the swashplate. Finally located it UNDER the MGB!! All we did was a track and balance on the head. Interesting machine, STRANGE people that build them....

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Hope this helps. Fly safe.