Hi,
When did spitfire Mk1s go over to constant speed props, was it during the Battle of Britain, and did all spits get the makeover or only those coming off the production line ?
What proportion of spits had them in the Battle of Britain ?
Was there a serial number beyond which constant speed was the standard and only type ?
What were they prior to the change ?
What if any were the visible changes to the spit, both in cockpit and on the hub ?
Am I right in saying the props were Hamilton Standard ?
DBenz
By: DBenz - 10th June 2010 at 23:39
Hi and thanks for all your feedback,
Were there any visible changes to controls in the cockpit ?
Any new levers on the throttle quadrant ?
DBenz
By: Arabella-Cox - 10th June 2010 at 18:44
CS Rotol props
We’ve visited this subject before on this Forum.
According to the contributors to that thread it seems that Rotol were a bit further ahead with their constand speed propeller developments during the first year of the war.
The Rotol electric props utilised the Curtiss Electric-designed propeller pitch change mechanism for their electric props, presumably as an alternative to hyydraulic should any serious production problems arrive with the hydraulic types.
de-Havilland used the Curtiss Electric design of hollow steel blade after WW2 allied to a hydromatic pitch change as the Curtiss Electric design was prone to frequent failures (this could be why Rotol didn’t use it much or pursue it) though the steel blade idea was OK.
Types to utilise this steel blade design propellers were the SaRo Princess, Britannia and Beverley.
Sorry, waffling off-thread again:D
Anon.
By: Edgar Brooks - 10th June 2010 at 12:54
According to Al Deere, in “Nine Lives,” 54 Squadron were trialling Rotol constant-speed props, during the Dunkirk evacuation.
Edgar
By: vanir - 10th June 2010 at 11:19
oh I was thinking of the Curtiss electric, not the Hamilton Standard (yes hydraulic).
curiously Rotols came in both hydraulic and electric (for multi-engine types)
By: dhfan - 10th June 2010 at 10:55
Between June 26th and August 15th 1940, DH engineers and squadron staff converted 1,051 Spitfires and Hurricanes from 2 speed to constant speed in the field.
By: Arabella-Cox - 10th June 2010 at 07:53
Early Spit props
Most Spitfires had two-position props by the beginning of the war and those not were soon converted from the big Watts fixed-pitch unit.
The constant-speed propeller (same propeller but with internal adjustments) modifications were carried out in the field in June/July 1940 as the further performance advantages were obvious by then.
de-Havilland propellers were licence-built Hamilton designs, Rotol being a home-designed product.
All Hamilton Standard props were hydraulic (apart from the early designs) and the name Hydromatic essentially meant Hydraulic & Automatic in the sense that once a prop RPM was selected from the cockpit the prop was governed to stay at that speed whatever the engine throttle setting or aircraft attitude.
Anon.
By: vanir - 10th June 2010 at 04:00
The Watts two-blade fixed pitch was early production standard, I’m not sure the timescale but fairly early on the De Havilland variable pitch (two settings, three blade) was standard factory equipment through to about June 1940 for the MkI Spit, and was retrofitted to Hurricanes (only those in France still had Watts). By Dunkirk pretty much the entire RAF home fighter force had De Havilland.
From June 1940 the Rotol (hydraulic) constant speed was introduced for production of MkII Spits and retrofitted to MkI. It’s a manual constant speed (ie. fully variable with incidence limiter) with about 35-deg travel.
The Hamilton Standard is electric and less prone to overspeeding in dives; iirc fitted from the MkV but a Spit expert would have to elaborate/correct as I’m running on a distant memory with that.
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June 10, 2010 at 12:38 am