powerandpassionTop of the Mountain moment
I climbed the mountain and asked the guru the question and he gave me the answer to the meaning of life in one sentence :
“Packard Merlin V1650 -3-7 were fitted with SAE50 prop shaft which means that 23E50 spiders will fit.”
I raced home and sure enough in AP 2616C V1650-3 or V1650-7 engine, made in the same factory, were fitted with AN No 50 shaft for US ( Canadian?) use and SBAC No 5 shaft for UK use (as well as being re badged as Merlin 68 or 69 for UK use). Same engine, different splined output shaft.
Then I raced to my Moorabbin Air Museum library copy of Mosquito prop accessory book which came with the Merlin 69 engine logbook. Sure enough the spider was a SBAC spider matching Hamilton Standard part number for 23EX spider for SBAC shaft.
Then I sat back and figured you can’t find a Merlin 68 or 69, but you are more likely to find a V1650-3 or V1650 -7. Or as the guru said, “find a AN No 50 shaft to fit to your Merlin”. So in terms of my original question, can I fit a DC3 prop hub to a Mosquito or Lancaster, the answer is :
1) Yes, if the Merlin has an SAE 50 prop shaft, which is not impossible to find and interchangeable with a SBAC shaft on a Packard built Merlin.
2) Yes, most of the hub parts are interchangeable with 23E50 hubs, but the distribution valve is different.
3) Can’t help you with 6519 blades, don’t know enough about that yet.
This, in combination with a glass of wine, led to a number of further thoughts :
4) In “Australia in the War of 39-45, War Economy 1942-45” by Butlin and Schedvin, there are many cabinet (Australian government decision making body of elected ministers) discussions which permeate alarm and concern about the cost of war production, particularly aircraft production. In simple terms, the credit card was maxed beyond its limit and the government was disturbed about how things would be paid for. Many discussions relate to cutting back ambitious aircraft production schemes developed in the panic of the Japanese attacks of late 1941. As soon as practically possible, aircraft manufacturing was curtailed. In the immediate postwar, reconfiguring resource allocation was the primary concern. It explains why there was no great surplus of aircraft parts after 1945, and why the metals allocated or alienated within aircraft parts stocks were rapidly reallocated to other uses. I understand that the UK government, while hiding behind the fig leaf of Lend Lease, was similarly in deep deficit. Today, it means you can’t find stocks of British or British designed war surplus.
5) In 1942, the Australian government, in the face of Japanese attacks on Darwin, introduced the “temporary” phenomenon of income tax, never before levied in the country. This, of course remains with us today. I do not know my US tax history, but I expect that the attack on Pearl Harbour allowed the US administration to introduce effective and novel tax measures in an irresistible environment. While for Australia, income tax helped, I suspect for the US, based on its population, it fundamentally changed the position of the US government by flooding it with money. This is the only circumstance which I can see explained the development of the postwar US military industrial complex and the fact that I can still find lots of WW2 US war surplus today, but very little UK or Australian.
6) This surplus was good, as it also funded the postwar redevelopment of West Germany and Japan, where for a number of years the Marshall Plan diverted 30% of US tax payer revenues into the reconstruction of these countries. Thank you American tax payer for funding 70 odd years of global peace. We are still cruising on the investment, but understand that the capacity and culture of the US tax payer to do so is no longer there. Nor is it within the culture of any other tax payer, unfortunately.
7) No one has anything to fear until the Chinese government reforms its income tax system.
Now, back to hydromatic props….or more wine:applause:
powerandpassionThat is quite fascinating information!
I concur.
Bloody Australians again, making things out of fencing wire. I guess the key issue today is finding an engineer to certify blade rework, since it appears that the OEM is not interested or commercially motivated to get involved in limited production runs of commercially unattractive historic work. This reaches its apogee of frustration with LH tractor blades for British radials, not a hope in hades of getting a product there in the usual way.
powerandpassion3D40 & 3D50
Just too long spent exploring the darkest recesses of the internet when I should be working!
You will be rewarded with some 3D40 or 3D50 hubs, all in good time, though I can’t help you with Peregrines ! Maybe early single stage Merlins, but then we still need to find a SBAC spline spider X 2 . Might need to machine those ones up from new….
powerandpassionA true artist speaks !
Geez we roused you up ! Bit like having a discussion in the pub about Vincent Van Gogh and his intent with brushstrokes on Sunflowers when the old sleeping drunk in the corner shoots up and says “I am Vincent !”:)
Thank you for sharing this absolute triple diamond level stuff. This is like Tom Cruise being let into the Thetan room, when everything is explained!
Still, ver ist der type 6519 for the Lancaster and Mozzie?! Somewhere I read paddle props were introduced in 1943, so do your documents end the month before?!
Absolutely loving this detail. You get a free membership of http://www.you_spin_my_prop.com !!
powerandpassionTall tail but true
Hi All
I guess many of you have been worrying about the second readout on the Televel gauge, :eagerness: so here is a pointer to the answer.
This is a picture of the gauge that replaced the Televel gauge on a later Mark of the Stirling, it has two readouts – On Ground and Cruising! Should have looked at this earlier I suppose…..
Since the Stirling had many fuel tanks of widely differing capacity each of the gauges are different and must have been made specifically for the Stirling.
James
James,
You have to look at the function of the Televel to work through the logic. See post #4. Tail up or tail down doesn’t alter the fact that you have to wind the float to get a reading. You would get a different reading with the aircraft in a different aspect but you would still have to wind the float. In your photo, in the windows that can be seen by my failing eyes, there are some windows at zero and some at 120 gallons, too discrepant for your tail down theory. It really looks like a panel after a long flight, engine oil temp coming down. The later Smiths electric gauge was linked to a cork float on an arm that would rise and float independently, linked to a ‘variac’ that would send a different electric signal, with an old school painted adjustment on the dial if the petrol sloshed to the back of an inclined tank.
Two windows on a Televel wound by one fingergrabbenscheisserschtik implies two tanks serviced by two cables coming out of a twin window, stacked dial display. This is just a guess, because your twin window Televel is a fascinating variant. We need to find one and see if two cables came out the back, or buy one on ebay and smash it open with a hammer to see if there are two stacked dials.:)
powerandpassionDoes anybody know why the deicing assembly was not included in 23EX assemblies ? Deicing is part of 23E50, I assume that, if prop deicing was required these components may have been used. I would have thought that PR Mosquitos would have prop deicing but cannot find any references to this in Mosquito manuals, only the humble windscreen deicing hand pump used across a number of British aircraft . Did only American aircraft have prop deicing up till 1945 ? All those missions in continental winters and no prop deicing ?
powerandpassionHow good is that !
6507 blades, with a deHav dome, HS hub and SBAC-5 spider. DAI
Fantastic, thanks for that, good to see an example.
powerandpassionThere is a reason for the absence of data on Hamilton Standard blades – Hamilton still regard even pre-war designs as secret, and won’t release any blade design data at all.
I must concur to the extent that I have yet to locate any publication which explains blade coding. The other day I tripped over a 6507 paddle blade which I swore was a 6519 Mosquito/Lancaster paddle blade but ‘twern’t. 6507 goes on DC4-C54-Corsair P&W radials, which are RH tractor.
One kind gent ‘in the know’ said to me there is no rythme or reason to blade coding, a blade with a sequential number to another may look entirely different.
I understand toothpick blades were progressively replaced with paddle blades on Lancasters from 1943 to convert more horsepower into thrust as more powerful Merlins variants were developed.
So maybe prefix 6 blades are ‘paddle designs’ ? I need to actually photograph each blade and put it next to its code number to start to see a pattern perhaps.
Interestingly the 6507 blade had another number, shank 56155, next to it, which looks like a typical HS number.
So I wonder if DH 40xxx and 50xxx blade numbers refer to HS part numbers, as I suspect they might.
I understand there are limits to cutting blades shorter, no doubt related to stress bearing calculations, viz distance from the root.
But if you can take a toothpick blade off a Lancaster and replace it with an utterly different paddle design, all of them evolved from RAF6, then why can’t I take a RH tractor DC3 blade and put it on a RH tractor Merlin hub assembly, on the assumption that a blade integrating with a 23E50 DC3 hub spider arm will integrate with a 23EX hub spider arm……
This becomes a question of blade/engine under/over performance, not part compatibility, excepting the throat clearing from regulators. Maybe the hydromatic mechanism itself will self adjust to different blade thrust characteristics, is it not the automatic transmission of the skies ?
Maybe there is no great secret. Maybe it was important in 1945 when 20mm cannon were hitting the wallet in your back pocket to have a 2% more efficient blade design, so tiny adjustments to blade profiles resulted in a different blade number. I did read that the shank of one design was fixed to deliver more cooling air into an engine duct, so HS were tweaking a basic design to do 2% things.
The only real way to prove this is to 3D laser scan remnant blades and lay the drawings them over each other and see what you see. Maybe this is the only way to convince somebody born in 1987 at HS/Avia that an available forging for a 6507 blade may be machined to a 6519 profile to keep Lancasters flying…
powerandpassionI Can’t add a huge amount to this as it has been covered but the 23EX prop hub assembly is identical to the 23E50 except the spider
23EX is developed from the 23E50 but they end up being quite different, different distributor valves and thus different internal geometry accomodated by different bits of whatsits and shims and packers and seals and thingymebobs. However some of the thingymebobs are generally sourced from other models so if you decide to sit in a cave and do nothing but recite the HS parts manual like a certain religious text then you start to see patterns emerge. I intend to start a dating site for young women looking for men who confidently know their HS part numbers, http://www.you_spin_my_prop.com
powerandpassionLooking in the HS interchangability list the following direct matches can be made in the hub :
Barrel assembly—No
Distributor Valve assembly—No
Dome assembly—No
Deicing assembly—No
Extra parts Group—Yes.So the direct answer is that you cannot take a Mustang hub and fit it to Lancaster or Mosquito, however there are some common parts in these non interchangeable hubs.
Getting deep into this can require a bottle of whiskey and a back massage, however on the barrel assembly of the 23EX (part 57470) and the variants of 24D50 (parts 57285 & 59648) the following individual parts are interchangeable : nothing !
Before automatically going for another bottle of whiskey and a slump more detailed analysis of the actual 23EX hub could show that what differences there are with the 24D50 and whether or not they may be insurmountable for adaptation to other, British aircraft types : really a Mustang would have a Packard Merlin and the 24D50 would have to fit a Merlin type shaft for starters. The Lancaster/Mosquito is a three blade and the Mustang is a 4 blade which is a subtlety , but probably the 4 blade barrel assembly is designed to handle more feathering fluid which could be usable for a three blade.. I know the feathering pumps on 4 bladed Lincolns are identical to three bladed Mosquito feathering pumps…probably need to go for a holiday to somewhere near Avia and work this out with them.
The 6547 Mustang blade and 6519 Mosquito Lancaster blade, now it is too late an night to explore that one right now..
When you see a learner driver timidly brushing the side of the gutter at slow speed then you see me in the world of HS hydromatic props. But the deeper I get in and the more wood I chop the more weight I put on the accelerator…one day I will be drifting sideways with a bottle of bourbon in may lap and Billy Idol on full bore.
So I now completely understand that the D series props were scaled down versions of the E series props, developed specifically for light, single engine fighters. So E series is Duplo and D series is Lego. So you can’t stick Duplo and Lego together, so it is unlikely that a hydromatic parts used on a single seat fighter will match parts used on a twin or bomber.
Then the interchangeability list is for guys that like to read a cereal packet from time to time, so it sticks to the big picture. It breaks a prop into 5 components, and if you can change one component while eating a hamburger in one hand it lets you do so. Where it thinks you might leave something like a spanner or coffee cup inside an assembly it gently leads you away and tells you there is no interchangeability.
For those who like to read Omar Khayyam’s Rubiayat in the original Persian, the Parts Manual details each nut and washer individually. On this level, you start to see that there is LOTS of commonality between items of HS manufacture, as you would expect to be from a profit driven Yankee enterprise. On this level you have to extract the individual parts and dump it into excel before you start to see the patterns, then as Omar would say :
“عاشر من الناس كبار العقول
وجانب الجهال أهل الفضول
واشرب نقيع السم من عاقل
واسكب على الأرض دواء الجهول”
powerandpassionDo you also know if DEHAVILLAND manufactured hydromatic parts are directly interchangeable with US manufactured hydromatic parts? Thank you
Finally after being left alone in the house with a bottle of Australian Shiraz and extracting part numbers from the 1944 HS Hydromatic Prop Part Manual and dumping this into excel and formatting into number sequence I have my Eureka moment ! In my trembling hands there is a copy of a 1945 RAAF Accessory Logbook for Australian deHavilland 23EX ADH Propellor from the Moorabbin Air Museum library. The principal part numbers displayed directly correlate with US HS part numbers, except being prefaced with an A, eg Australian A56342 Barrel = US 56342 Barrel. Much in the manner Australian manufactured cockpit instruments prefaced 6A with G6A, to allow consistent comparison with Air Ministry instrument schedules. It makes sense that ADH would not change part numbers, and here is proof that the Australians are sensible folk indeed. So even though wise and good people have said that ADH and US HS parts are interchangeable, I can now point to written confirmation of the fact that the same parts have the same numeric code, even tho they be made upon separate cheeks of the Pacific.
Please support the retention and preservation of obscure technical manuals and paperwork, you never know how they will come in useful in the decades ahead. Thank you library, I love you.:love-struck::love-struck::love-struck:
powerandpassionVickers Potts Oil Coolers
The scrap arrived in a yard not far from me so if any one needs some oil coolers speak up now as I may be able to rescue them before they get crushed the rest is already pans. A pair of static wheels are also Available to a good home.
Definitely want oil coolers and most particularly the duralumin tee pieces at the top of the coolers. If the brass fins have already been scrapped or damaged then the tee pieces are what I am most after. I would be grateful if these could be saved. Also mainwheel oleo struts if the U/C is being scrapped or has been damaged.
Also a little piece of identifiable (to aircraft and position in frame) fuselage tube that fits in the hand for metallurgical testing.
Any electrical components like metal fuseboxs, plugs, terminals.
Shame for all this stuff to go to a scrappie in 2015.:apologetic:
I would be happy to donate cash for total scrap value if the scrappie holds off destroying what is left and allows anybody to come in and pick up things over the next few months in return for somebody local coordinating dispersal of items to good homes. What’s left ? How much does he want ?
powerandpassionRogier, thank you again. Can I ask you to post a link to this thread on the raf in Suffolk forum, I don’t want end up on too many forums as I get clipped on the ear just for being on this one for too long when apparently I should be cleaning gutters….
powerandpassion‘Veteran and Vintage Aircraft 1968’ by L Hunt lists Lincoln B2 RF398 at RAF Henlow, but in the index under Lincolns it shows two airframes in total surviving in 1968. [NB 22 Mosquitos !!] I assume this second one is RF 342 now at Moorabbin ? Can get some pics as it is down the road….
powerandpassionWatch the rotor baldes
A very interesting topic. We have a Cierva C30A frame at the Helicopter Museum which some are keen to restore but which has quite a lot of corrosion etc. I wonder what type of iron that is made of.I assume it didn’t need the strength and format to withstand the same stresses as a Demon etc but the C30s were built by Avro so …..
What a great project ! I do not know the composition of the fuselage but as you mention it is Avro built and contemporary of the Anson so may be welded T45 which won’t be such a problem to source. Metallurgical testing on a loose piece no bigger than your fingernail should confirm the chemistry of the tube and you can get a copy of the T45 standard for the 1930’s from British Standards.
Don’t damage the rotor blades because they will be very, very difficult to replace. From ‘Aircraft Engineering June 1931, pg 143 Seamless steel tubes for Aircraft by Austyn Reynolds’ (Reynolds Tube Co) :
“One recent example now being supplied comprises taper gauge tubes of 15 ft length for Autogiro blade spars. The thickness of these tubes is tapered for practically the whole length. These tubes are made from air hardened nickel chrome steel [ NB same as DTD54a/BS S88c aircraft spars] and are hardened and tempered to give 85 tons per sq inch ultimate stress.”
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