Rolls Royce Avon question...

Member for

8 years 2 months

Posts: 67

Someone must know how to take an Avon apart!

Our aviation musuem has a very sad looking RR Avon which we would like to put on display. We could just scrub it up, treat the rust and apply a lick of paint.

However some of us would like to be a bit more ambitious and hope to open the engine up to show the insides.

I have searched for information but I cant find information on how to dismantle the engine. For example although it appears the 'top' half of the primpary compressor could just be unbolted and lifted out I see other references which tend to indicate these engines are dismantled by standing them face down on a rubber pad and I assume taking bits off from the rear end.

Please, does anyone know how to open one of these by non-distructive means?

Thanks

Original post
Profile picture for user Peter

Member for

19 years 11 months

Posts: 10,012

Try contacting the LPG at Bruntingthorpe

Member for

13 years 7 months

Posts: 3,778

Jet wash it, then treat rusty areas with Deox Gel and then apply liberal amounts of ferosol, wipe and transform.
Someone I know has an early Avon up for sale and i has been dicused to do the same to that before departure

Profile picture for user pagen01

Member for

12 years 3 months

Posts: 10,647

In the temporary absence of a far more qualified answer, with the engine sitting correctly I thought that the compressor housing could be split by removing the bolts at each horizontal edge, and from the upper half radius of the front and rear mating ridges.

Rolls Royce Avon 200 Series

Rolls Royce Avon 100 Series RA3

Rolls Royce Avon 100 Series

Be interesting to see updates and pictures of your project John, I do like the Avon.

Profile picture for user mjr

Member for

15 years 11 months

Posts: 728

You can split the comp shell off, but you will need the stator retaining tools in order to get the shgell back together, otherwise you will not line the stators back up in the compressor case. Dont split it uinless you have that tool!

Before you take any tools, sand paper or any other abrassive material to it, what mark of Avon is it? is it a 200 or 300 series?

Member for

10 years 8 months

Posts: 281

Part of my FT course was blade blending on an Avon and it is a 'simple' job as James has described above to remove the Compressor top half casing to expose the Blades. I don't think you can do anything with the hot end without specialist tools but I could be wrong.

A word of warning though, if you don't lock the rotating assembly, somebody will put fingers in and turn the Compressor. I know 300 series and think some, if not all the others had an anti rotation brake fitted which meant the engine will only turn one way. What happens is the inertia of the big rotating mass drags fingers in and they get wedged. You can't turn the engine in the opposite direction because of the stop, so the only way to get the trapped fingers out is to get the bolt croppers out of stores. (I would strongly advise that they are used on the blades not the fingers - however, the preservationist in me thinks otherwise!)

I too am a big fan* of the Avon so would love to see pictures too.

*The Avon was a turbojet not a turbofan before anyone says anytihing!

Member for

8 years 2 months

Posts: 67

Thanks for the comments everyone, I think we would be very pleased to get it to something like the second picture! We have a very similar stand that it is on.

I dont think we are concerned about ever having to put it back together but it is something to bear in mind.

Mjr, fortunately the plate is still on so I should be able to find that when I go out there tomorrow. Are you cautioning about magnesium alloys?

John

Member for

14 years 8 months

Posts: 2,895

Have you tried Rolls-Royce Heritage Trust at R-R, Derby?

As has been alluded to beware of visitor's fingers and provide clear plastic sheet guards otherwise HSE might not be too happy.

Roger Smith.

Profile picture for user pagen01

Member for

12 years 3 months

Posts: 10,647

Just out of interest John, is the Avon you have an early 'cannular' 100 series or one of the later annular 200/300 series, where is the museum?

Member for

14 years 4 months

Posts: 358

John,

If memory serves me well, once the compressor top half case is undone, you will have to install what we called 'knives' into the horizontal gap (I think these may be the stator tools mjr is referring to). These 'knives' prevent the stator blades from falling out of the upper compressor case - and into the lower exposed compressor half.

The ratchet pawl anti-rotation mechanism balofski refers to was installed on Lightening Avons - as they shared the same intake, the first engine starting would have drawn air backwards through the other engine causing it to rotate in the wrong direction - the ratchet pawls prevented this.

camlobe

Member for

8 years 2 months

Posts: 67

Just out of interest John, is the Avon you have an early 'cannular' 100 series or one of the later annular 200/300 series, where is the museum?

Hi, the engine plate shows 'ECU 20701 C" which I believe is a Hunter or Canberra variant, 200 series.

The museum is in Ashburton, New Zealand (about 80kms from Christchurch).

Member for

8 years 2 months

Posts: 67

Thanks Camlobe, so the blades are loose in their holders?

Thanks for the ratchet information, I have turned the ancilliary drive and it seems easy enough to turn it both ways, I have not been brave enough to poke my fingers in the front end!

John

Profile picture for user ZRX61

Member for

14 years 6 months

Posts: 4,796

A word of warning though, if you don't lock the rotating assembly, somebody will put fingers in and turn the Compressor. I know 300 series and think some, if not all the others had an anti rotation brake fitted which meant the engine will only turn one way. What happens is the inertia of the big rotating mass drags fingers in and they get wedged. You can't turn the engine in the opposite direction because of the stop, so the only way to get the trapped fingers out is to get the bolt croppers out of stores. (I would strongly advise that they are used on the blades not the fingers - however, the preservationist in me thinks otherwise!)

A&P student I knew about 20 years ago wound up a jet engine by using a finger... & then his hand slipped, neatly removed his digit at the 2nd knuckle. Not sure if they ever took the engine apart to get the finger out, I know we could smell the damn thing rotting away for at least a couple of weeks after..

Member for

10 years 8 months

Posts: 281

Just out of interest John, is the Avon you have an early 'cannular' 100 series or one of the later annular 200/300 series, where is the museum?

With my total pedantic hat firmly seated on my bonce:

Early Avons were Canned or Cannular (you can see the combustors)

Later Avons are Canannular (the combustors are moved inside the engine)

And Annular where the bit between the back of the compressor and front of the turbine is effectively one big combustor, 'modern' engines such as the RB199.

Pedant hat off.

The Avon is the stand out gas turbine of all time. First flown in the late 1940s and operational in the first Canberras in the 50s. 62 years on it is still fully supported by Rolls Royce in the gas generator variants for the oil. gas and power generation industries. I think they even ran them on liquified coal dust!

Member for

8 years 2 months

Posts: 67

This engine has a plain cover over where I expect the combusters are. :cool:

Profile picture for user pagen01

Member for

12 years 3 months

Posts: 10,647

Baloffski, I've only known the latter types as annular, certainly that's how RR and Flight referred to it in the earlier days, though I have seen referrence to it as can-annular. As they still have individual combustion tubes (8?) but placed within a single casing, can-annular is a better description.

John, Yes that's a later can-annular type you have, the 207 is the 10K + Ib thrust Avon for the late Mk Hunters such as the FGA.9 and exports. Mk207 equated to RA.28 in Rolls parlance. Should look like the first engine in my above pics.