Lockheed 12 (Electra jr)

[Zreyn]

For anyone interested in old airplanes you might want to check out this website of my friends 1936 Lockheed 12
http://electrajr.com/Amelia.html

[johneeb]

Very nice airplane

[Zreyn]

Thanks johneeb,Maybe your response will be enough to help others who want to look or maybe I should repost since I don't know how to change that one?

[15A]

Good lookin' plane! But I've never seen a registration number with NR. Can anyone explain?

[Bruce Fenstermacher]

My guess would be the R is for Restricted.

[Zreyn]

Your guess would be correct Bruce,these pics are of course what Joe (being the movie stare that he is)calls "being in costume"& her airplane was so modified for her attempt that it required a restricted catagory

[blueldr]

That's a really beautiful Lockheed airplane. I notice that it is equipped with H.S. Baby Hydromatic propellers. I'm sure these props are a substantial improvement over the pre WWII H.S. Constant Speed props originally used which were unable to be feathered in an emergency engine shut down. I believe the Baby Hydromatic was a post WWii development since it was some time after the war before I ever saw one.

[hilltop170]

BL-
Do you know if the hydromatic props shut down in low pitch like modern props or in high pitch like the old Ham Std 2B-20s?

[15A]

Do I need to change my registration to an NR too?
My plane went in for its annual and sprouted another leg!

It's a 4 wheeler now!

[blueldr]

Richard,
On the old H.S. Constant Speed props engine oil pressure forced the cylinder forward to put the prop in low pitch (high RPM). Centrifugal twisting moment and the counter weights forced the cylinder to the rear as the oil was bled off back into the engine. returning the prop to high pitch (low RPM).
Engine out procedure called for pulling the prop control to the rear returning the prop to high pitch (low RPM) for minimum drag on the rotating engine.
This is the type of propeller that is used on the AT-6/SNJ airplanes that you still see today. Back during WWII, all of the Beech 18 series airplanes such as the AT-7,AT-11, C-45, and their Navy equivalents were equipped with this type of prop on the P&W R-985 AN-1 engines. On these airplanes oil to the prop was controlled through a governor which made it a constant speed setup. The same engine and propeller used on the Basic trainers such as the BT-13/ SNV
was a two position prop since control was through a simple oil control valve, rather than a governor, which only provided for oil pressure "On and Off" Providing low pitch for take off and climb and high pitch for cruise. There were minor differences in the settings of the mechanical stops in the props.
With an engine and the prop windmilling, a twin Beech is a definite candidate for a landind ASAP.
With the development of the Baby Hydromatic prop, I believe the Engines were modified to the AN-14 configuration since a hydromatic prop has oil on both sides of the piston within the dome.

[hilltop170]

Thanks BL-
I understand your very good explanation of the old style Ham Std props.

It is my understanding if the old style props are shut down in low pitch with the dome oil volume at its maximum, upon startup the next time, the first oil flow goes to fill up the empty dome (path of least resistance) before the oil pump can pressure up oil to the bearings and the rest of the system allowing the engine to be running for some time with no oil pressure. Hard on the master rod bearing.

Conversly, shutting down the old style props in high pitch minimizes the volume in the dome which will fill with oil much quicker upon the next startup allowing the system oil pressure to increase more radidly.

I did not see in your reply whether the hydromatic props are shut down in high pitch like the old style Ham Stds or low pitch like modern props. Just curious as I saw a C-47 pilot shut down in low pitch. Just wondering if that was correct.

[blueldr]

Richard,
The normal shutdown procedure with the H.S. Constant Speed orTwo Position propellers was to bleed the oil off to position the prop in high pitch (Low RPM). This caused the Cylinder to pull back and cover the piston thus protecting the surface from the weather and dirt which would otherwise collect on the slightly oily mating surface of the piston. Dirt or grit collecting on the mating surface of the piston could cause excessive wear on the interior seal in the cylinder thus creating an oil leak. If the shut down period was extensive, the weather would wash off the risidual oil on an exposed piston and allow rust to form.
A good many R-985 and R-1340 engines nowadays have spinners installed which completely enclose the working mechanism of those type propellers.
During WWII we did not have these spinners on any of the airplanes that I ever flew. I would expect that these spinners would provide a measure of protection that might allow an opposite shut down procedure.
I cannot remember what the normal shutdown procedure was on the Hydromatic propellers. And the strange part is that I spent a good many more hours flying Hydromatic and Hydromatic Reversible peopellers than I did on the old Constant Speeds.