The A2A Simulations Community

"Come share your passion for flight"
It is currently Thu Sep 20, 2018 12:28 pm

All times are UTC - 5 hours




Post new topic Reply to topic  [ 5 posts ] 
Author Message
PostPosted: Sun Jan 04, 2015 8:21 am 
Offline
Staff Sergeant

Joined: Sat Nov 24, 2012 4:25 am
Posts: 285
Location: Morges, on lake of Geneva, Switzerland
Does anyone have a clear understanding why the Rotol CS propeller was choosen instead of the de Havilland CS ? I guess a difference in the performance explains the choice?
And is it correct that the first CS to be implemented on the Mark ones was the de Havilland to be replaced by Rotols? and is it correct that the Mark twos all had Rotol CS propellers?

_________________
Image
Image
Image


Top
 Profile  
 
PostPosted: Sun Jan 04, 2015 9:05 am 
Offline
Senior Airman
User avatar

Joined: Sun Jul 01, 2012 5:35 pm
Posts: 240
Location: EGSC
francesco.doenz wrote:
Does anyone have a clear understanding why the Rotol CS propeller was choosen instead of the de Havilland CS ? I guess a difference in the performance explains the choice?
And is it correct that the first CS to be implemented on the Mark ones was the de Havilland to be replaced by Rotols? and is it correct that the Mark twos all had Rotol CS propellers?


Not too sure why Rotol was use as apposed to DH after the Mk.I / Mk.II Sptifires. I guess It might have something to do with DH being too busy full filling other contracts and the minor detail of Mosquito Production and development after November 1940.

According to Spitfire The History (AKA The Bible) by Morgan & Shacklady. The first Spitfire fitted with the DH CS unit was an off the books affair. DH had started construction of 500 conversion kits, which included all oil piping for the engine as RR were too busy producing and developing Merlins, without a formal contract from the Air Ministry. Fitting of the kits started 24 June and all Spitfire and Hurricane squadrons were equipped by 16 August. By March 43 the Air Ministry was still asking for proof that the units had been fitted lol.

_________________
Image


Top
 Profile  
 
PostPosted: Mon Jan 05, 2015 1:49 pm 
Offline
Senior Airman

Joined: Sun Dec 26, 2004 5:19 pm
Posts: 165
As you are aware, the A2A MKI represents the earlier MKI with the two pitch de havilland propeller (5/20 Merlin II, or 5/21 Merlin III).

The history of the CS prop upgrade for the Spitfire is as posted by matt, so it was either a Rotol CS or DH CS unit.

The MKII had a either the Rotol CS RX5/1 with Magnesium blades, the RX5/3 with Jablo or Hydulignum (wooden) blades, or the RX5/10 with Jablo blades. It also used the de havilland CS 5/39A with Dural blades.

I would really like it if somewhere down the line A2A did a later MKI with the DH CS prop, and the later automatic landing gear lever, as per the MKII, so fingers crossed! (I would love the MKV too!)

Cheers

Paul


Top
 Profile  
 
PostPosted: Thu Jan 08, 2015 8:58 pm 
Offline
Senior Master Sergeant
User avatar

Joined: Sun Jan 30, 2011 3:39 pm
Posts: 1919
Location: Northern New Jersey
My tiny wish was always for a simple iron gunsight when using the flat canopy or 2 blade prop... the refelctor sight doesn't seem right in a 1938/9 configuration, which is often my choice!

I'd love A2A to "prove" Accusim by dropping the basic Spitfire MkI innards in a Hurricane MkI airframe just for fun... I'd love to fly and feel the differences between the two classic British Merlin fighters!

Sorry- a tad OT :mrgreen:

Joe

_________________
Joe


Top
 Profile  
 
PostPosted: Thu Jan 08, 2015 10:18 pm 
Offline
Master Sergeant

Joined: Mon Aug 26, 2013 10:03 pm
Posts: 1263
Location: Perth, W. Aust
Rotol was a joint venture set up by Bristol Aircraft and Rolls Royce (hence Rotol; RO from Rolls Royce and TOL from Bristol) to manufacture constant speed propellers, as De Havillands were unlikely to be able to produce "their" CS unit in large enough numbers. I say "their" CS prop because it was it was in fact a license built version of the Hamilton Standard CS propeller. The Rotol propeller went on to become the "standard" prop only on Spitfires from the MkIX, I believe, but on earlier marks, both DH and Rotol props were used.

The MkVc Spitfires that fought the Darwin campaign in 1943 all had the DH prop, and it gave a lot of trouble with overspeeding. The standard tactic was to get above the inbound Japanese, who had learned from the 1942 campaign to approach at 28,000ft, which was about the limit of the escorting Zeros. So the Spifires climbed to 30,000ft at which height the oil in the CS unit congealed. Investigation in Australia showed that the bleed back ports between the front and rear chambers of the CS mechanism were too small, and when the plane was nosed over into a dive, the propeller was likely to act as a fixed pitch unit, resulting in an over-speed.

Some of the MkV's used in the defense of Malta were also equipped with the DH prop. The Rotol prop was used for the most part, but was slower revving than the DH unit, and Spitfires equipped with the DH prop had an extra 500rpm to develop more power to get off the smaller British carriers used later in 1942 to re-equip the Malta garrison. The Rotol unit was OK for getting Spitfires off the larger US carriers used earlier, but when the USS Wasp was lost, the British had to use their smaller carriers. This is something those of us who change props on the A2A model can appreciate :) . I believe that most early Seafires were equipped with the DH unit, because of the need top get off Britain's smaller carriers, but as they didn't generally fight at the same altitudes as the RAAF at Darwin, the inherent design fault of the DH manufactures unit wasn't an issue.

Please note that I don't claim that the above is in any way definitive. The more I read on the subject, the more I realise that there is more to be researched. Morgan and Shacklady's book is very good, but should be read along with others. Wartime operational necessities in all the campaigns that the Spitfire took part in meant that the standard Spitfire, of any mark, is not the Spitfire that might have been used in the field.


Cheers,
Mike

_________________
ImageImageImageImage


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 1 guest


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Search for:
Jump to:  
Powered by phpBB® Forum Software © phpBB Group