First question is about the Merlin 130 series. This is something that I’ve wondered about since I saw a diagram on Flight Global’s site depicting a DH Hornet nacelle and a DH Mosquito nacelle from the later two stage Merlin equipped version.
I know that the Hornet’s nacelle has less frontal area than the Mosquito’s, but I’m wondering how much of that is due to actual engine frontal area vs accessory rearrangement and the changes in the supercharger intake (down-draught on the Merlin 130 series) and the Hornet using a more compact landing gear unit.
I’m basing the question off of stills I saw of a Sea Hornet 21 being built up at Hatfield in 1948 at British Pathe and photos of the close up of the restored Mosquito KA114′ engine nacelles, and photos of both the Hornet and Mosquito without the cowlings on their nacelles. It’s also worth noting that the Hornet and single stage Mosquitoes’ frontal area of their nacelles is roughly that it seems of a P-51 Mustang or a F-82 Twin Mustang’s power unit. So is it that the Merlin 130 family is physically of smaller frontal area, or is it in how accessories are arranged and other factors, such as the Hornet’s more compact landing gear, since I did read that the Hornet’s nacelles were roughly 20-25% smaller in frontal area than the Mosquito’s.
This also leads me to later Merlin variants. I know that there was a Merlin 140, that seemed to be a version of the 130 that reverted to an updraught supercharger intake, but the only aircraft that I can name that was fitted with it was the Short Sturgeon. And then I know of the civil rated engines that have been used in various aircraft, such as the Hispano Buchons and CASA build He-111s, and various commercial aircraft and in rebuilt WWII fighters. I can name the 500 and 600 series, but were there more variants, and how extensive did the numbering go?
By: ChernKStewfan - 24th December 2012 at 22:54
Mostly what I’m trying to figure out is what dictated the differences in frontal area between a Hornet nacelle and a Mosquito nacelle, and if the 130 engines were truly unique specimens, (ie, few if any parts would interchange with other members of the 100 family, or earlier 2 stage Merlins). I don’t think that the engine frontal area is much different aside from accessory arrangements (supercharger intake mainly, and the Hornet’s intercooler being integrated with the radiator/oil cooler matrix)
Also, I’ve been wondering why the area between the spinner and exhaust outlets on the Hornet vs the Mosquito seems to be longer. Of course, it doesn’t help that I haven’t been able to see any HQ photos of a Hornet’s engine bay recently (DC’s Hornet/Sea Hornet book is part of my collection, and is buried in a plastic tote with all other kinds of collectable stuff in it’s original box). But, and this is a rough estimate, it seems that the armored spinner back plates on the Sea Hornet assembly line stills on British Pathe and photos of the final build of KA114 (the only currently fully airworthy Mosquito), the back plate diameter looks about the same, and surface area seems similar, along with those that I’ve seen of the back plates fitted to Packard V-1650 powered Mustangs.
By: trekbuster - 23rd December 2012 at 13:00
according to the book mentioned above the basic changes for 100 series engines over previous series were:
end feed crank lubrication
over hung first stage of two stage supercharger
improved intake elbow and single point fuel injection
these mods allowed +30lbs boost
for Hornet installation 130/131, down draft intake and moved the main coolant pump from below to the side, 131 with idler gear to reverse propeller rotation
the 100 series formed the basis of 600 and 700 series commercial engines
By: minimans - 23rd December 2012 at 06:39
I cant answer your question directly but if its Merlin 100 series engines you need info on you really need to get a copy of the Rolls-Royce Heritage trusts book “The Merlin 100 Series” by Alec Harvey-Bailey and Dave Piggott. I guarantee your brain will swell with the amount of information contained in this book!!! Its in the Historical series #19
Sign In
December 23, 2012 at 4:29 am