More Airfield bits

[ian_]

Sounds worth a go Nick, it wasn't just WWIG who missed bits, the Mohawk dug back in the Eighties left 5 Brownings along with a lot of very interesting cockpit stuff. The gauge is one of the brass bodied early type. Thanks for the id on the lamp Versuch, it's a 5c/678 which Bruce/GB airspares is selling as Mosquito/Vampire. The last piece is an 'Exactor' prop pitch control from a Whitley. Well done with the 109 Gareth! The French do lay on a good spread, you did well with the digger after a mid morning and lunchtime skinfull.

[NickW]

Camper van, thats a bit up market. We tend to rough it out the night before which normally involes getting drunk, hopefully making the dig but have been known to miss one! plus a little refreshments on site

Nick Permissions about sorted today for SSSI which is good news for the me109, now just have to get around the next hurdles for some summer digging on a bob spitfire and bob hurricane site which lie on a sheduled monument and area of outstanding natural beauty. I can really pick um!

Like the sound of the arrangements - very civilised - its just that I like to keep warm too! not to mention dry! If in the future anyone re-visits our digs we have left our trademark in the form of beer bottles at the bottom of the holes Re the other sites - that's why they are still there! It just needs the likes of you and me with the perseverence to overcome the obstacles

[NickW]

Well you can see form the picture, the plate is looking a bit more recognisable now - it was a nerve wracking process as it has to be the most tightly folded one I have ever tried to straighten + very fragile with some corrosion and already cracked along some of the worst folds. But I managed it a bit at a time with no further splitting - plenty of heating and patience



PS the serial number matches the Form 1180 too!

[Whitehunter]

Well done with the straighting i bet that took some time

[fighterace]

Nice one, out of interest can any one explain why all engines plates are from the "right hand tractor unit" where the left one gone!

[NickW]

I think all wartime Merlins were right hand tractor? Obviously for single engined aircraft it made sense to have them all the same. For allied multi engined aircraft, I can only think of the P-38 that had two different, though I recall they found it didnt make much difference.

[NickW]

Hi Ian - At Elvington today I spotted Tony Agar's Mossie was minus its engines - again! Took the opportunity to take the photo below:



Looks an exact match for the ones you found - there are two on each firewall and they are slightly different to my Defiant one.

[ian_]

Thanks Nick, that's excellent! Was the meeting well attended? Very good museum but too far from home.

[skypilot]

I think all wartime Merlins were right hand tractor? Obviously for single engined aircraft it made sense to have them all the same. For allied multi engined aircraft, I can only think of the P-38 that had two different, though I recall they found it didnt make much difference.

If I can add my anorak additional information....?

The "Right hand..." refers to the direction in which the prop turns when viewed form behind i.e. clockwise. A "Left hand" would therefore be anti-clockwise. You may wonder why the different types......with a single engined aircraft it matters very little generally speaking but with a multi-engined aircraft it can make a world of difference.

Anorak bit, based on a twin engined aircraft with RH engines:
Props produce slipstream (prop wash) which flows back over the airframe. Depending on the position of the engines, depends on the effect that this slipstream has. For example, if the engines are positioned close to the fuselage, the loss of an engine will produce less of an assymetric thrust effect. However, there may be less propwash flowing over vital tail control surfaces, most especially the rudder which can make control very difficult in such circumstances. Having two engines rotating in the same direction can exaggerate the problems of assymetry when an engine is lost on the right hand side as the left hand engine will creat a much greater assymetric effect, thus the RH engine is deemed the "critical engine" - to lose it would be potentially more critical. A double boomed tail assembly like that of many WW2 aircraft (P-38, Lancaster, Halifax etc) would perhaps have less of an need for different rotating props - I am no aerodynamisist!

If an aircraft has two engines rotating in opposite directions, the assymetric effect is more equal and thus there is not a designated "critical engine". As mentioned though, there is no one rule for all and airframe design has a large influence over engine direction, positioning etc. Whilst 2 engines have been mentioned, the same principal can be applied to any aircraft with equal numbers of engines on each wing.

Jets do not suffer in quite the same way as they do not have prop wash (obviously!) although assymetry is still an issue on aircraft with wing mounted engines such as B737 etc. Jets with tail mounted engines suffer much less from assymetry in an engine failure scenario.

Having flown commercial turbo-props and jets for a number of years i can vouch for the theory as being a reality, mainly in the simulator although I have had the "pleasure" of putting it to the test in real life too - thankfully leaving no relics for future digs and the only casualties being a few pairs of underpants!

[skypilot]

All these cracking pictures etc. have got my digging juices flowing again and so I have dug through my archive material and can offer the following info:

Post #15; picture 2: 6A/1032 - Compass Corrector No.3 for P4 P6 & P8 compasses