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By: - 18th October 2021 at 11:04 Permalink
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By: - 18th October 2021 at 11:29 Permalink
Posts: 1,306
By: - 19th October 2021 at 04:46 Permalink
I'm afraid I have nothing to offer than enthusiasm. What a special project!
By: - 21st October 2021 at 14:56 Permalink
What a lovely project and a lovely engine, they must sound amazing.
By: - 21st October 2021 at 16:42 Permalink
My goodness you will have some work on your hands. I wish you all the best with it and every success.
By: - 22nd October 2021 at 06:49 Permalink
Thanks KNZ, TA & Tom. There is a gent who hand crafted a scale, mechanically functioning Dagger, which is climbing Everest without oxygen, so I figure a standard old engine is less of a mountain! Currently casting complex 80 year old engine bits to reestablish tolerances, so not an impossible thing, just better not to think too deeply and do it. Really need to find old bits to confirm metallurgy and ‘self evident’ 80 year Napier old shop practice, like individually weighing and marking fractional components. Dagger bits must be around, largely unrecognised. Its in the ‘piles of stuff’ category.
By: - 22nd October 2021 at 18:58 Permalink
I believe the engine from Hector K8096 was amongst the wreckage on Red Pike in the Lake District. That was in the 1960s. It may still be there!
By: - 22nd October 2021 at 23:51 Permalink
Thanks AT, I have seen photos and though the Red Peak remains should stay it appears various bits have wandered off over the years. The value of these for restoration purposes is to validate detail, so photos are as good as anything, particularly as the project is in Australia. An example are the engine feet, and understanding what material these were made out of, as these seem to be intact on the wreck. Also the prop hub details and basic details like prop hub bolts. If anybody ever wants to hike up with a camera and vernier calipers, please let me know!
By: - 31st March 2022 at 01:27 Permalink
I don't suppose this could be from a Napier Dagger could it? It is a bit small for a larger aero-engine.
I'm not sure it is even aero (other that it came with some other aero-engine bits)?
By: - 3rd April 2022 at 07:49 Permalink - Edited 3rd April 2022 at 07:50
Rat’s eye view of rockers
By: - 3rd April 2022 at 07:57 Permalink
CD, thank you for posting up the ‘mystery rocker’ but I do not think it fits Dagger. The Dagger was the world’s first engine with hydraulic tappets, invented by Frank Halford, and apart from this feature, the rockers seem to have been made, on a precautionary principle, very robust, with a pronounced offset to fit within the tight geometry.
By: - 16th April 2022 at 23:40 Permalink
That rocker was a long-shot at best; another one for the 'mystery box' I guess!
Was the Dagger really the first engine in history with hydraulic-tappets; that's an interesting piece of engine history (or a good question for a very specific pub-quiz)! The more I learn about Frank Halford the more fascinating he becomes; there cannot have been many people who flew in combat in the First World War, rode in the Isle-of-Man TT and drove in the British Grand Prix (in a car of his own design)! Apparently, he also had some involvement with some obscure aero-engines!
Anyway, I dug this out for your amusement.
When I bought it I was told it was made from a Napier Sabre piston (it isn't!) and was assured it came from a Napier & Son employee. There isn't much left of it to help with identification (and it is far too small to be made from a Sabre piston) but at 96.30mm in diameter it is almost exactly the right size for a Napier Dagger piston?
Posts: 1,374
By: powerandpassion - 18th October 2021 at 11:02
The Napier Dagger engine was the poppet valve H24 precursor to the sleeve valve H24 Napier Sabre. It was used as the Dagger III in the Hawker Hector and Dagger VIII Handley Page Hereford. It was the first engine with the innovation hydraulic tappets and was designed to metric dimensions by Frank Halford. Another innovation was the use of magnesium for valve train casting blocks, an approach carrying over to the Halford designed dH Gypsy King 12 cylinder engine used in the dH Albatross and Sabre engines. Making materials with differential expansion work in high RPM, air cooled designs was pushing the design envelope, and the Dagger tells a story of both Napiers as a culture and the highly competitive, company betting innovation culture characteristic of 20th century founder-directors in their prime. If anything, telling this story and permitting the young to be prodded into risk taking by historical example is worth forcing a Dagger back to life. There is some remaining footage of Hectors in flight with the astonishing, guttral growl of Daggers in full roar. The sound is like a deeper, more urgent, more three dimensional Merlin, twice the cylinders moving at a higher RPM, with an obsession around balancing every nut and bolt to get the short throw pistons up to 5000RPM. Through the kindness of the Napier Power Heritage Trust a Dagger powerbank core has been obtained. This might have originated from a famous scrapyard lost in the mists of time, but apparently a number of these engines ornamented said yard. Would it be rude to ask if anybody has any Dagger bits laying around? These would be gratefully reunited with the core in a long term project to get a Dagger going again.