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205 Dual Hydraulic Conversion


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If I'm not mistaken, all 205A-1's were delivered WITH dual hydraulics...thats what the A-1 designation was....up-graded hydraulics, and tail rotors.  If I'm wrong, somebody 'educate' me.

How does a 205 get designated an A-1 without the dual hydraulics?


Our company has an A-1, brand spankin from bell in 1970, beit upgraded tailboom and tailrotor at a later date but still has single hydraulics.

From what I can understand is that not only the upgraded tailboom and tailrotor, designate the A-1, but also the change from the -11 to a -13A or -13B.


Maybe the later models of the A-1 were pushed off the line with the dual hydraulics.


I have flown a few 205A-1's and 204B with dual hydraulics that were factory installed, maybe an option?


I stand to be corrected!

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Taken from my Field Maintenance Course Bell 205A-1.


205A-1 helicopters serial number 30128 and subsequent and prior helicopters incorporating Service Instruction 205-37 are equipped with main rotor cyclic control servo actuators that are powered by two seperate and completely independaent gravity feed hydraulic systems. The system is referred tp System 1 and System 2. In addition to powering the cyclic control dual servo actuators, System 1 powers the tail rotor servo actuator and system 2 powers the main rotor collective actuator.


As you can see it is a Service Insruction and not mandatory. The dual hydraulics are the first Bell 212 parts incoroprated on the 205.


The standard engine for the 205A-1 is the Lycoming T5313, with a five minute take-off rating at sea level of 1250 shaft HP and continuous at 1100 shaft HP.


I would imagine that the SI 205-37 explains every thing in detail.


Have not had any conversion history, myself, but if I was going to do it I would contact Eagle Copters in YYC.


If you want to know why the dual hydraulics in a 205, try landing it without hydraulics and I mean a full on auto. I've done it with the dual's shut off on a 205.



Cheers, Don

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The various chnages in the 205 were as Blackmac stated and were the result of trying to cure on-going problems that started with the 204 model in 'Nam'. The 1st major one to be corrected was the boost pumps. The 204's were electric and that was all fine until shell fire took out some part of the electrics and now you had no boost pumps. This, in itself was no big problem, EXCEPT if you were in the highlands of 'Nam" and then things got 'dicey'. Vietnam is thought of as jungle and flat, which is true for some parts, but they have a substantuial mountain range also. Therefore, on the 205 you have one electric boost pump and one activated by bleed-air....problem solved.


The very original tail-booms on the first 205's, were in reality, the 204 tail-boom. That didn't last long at all and the 205 got it's own. Having said that, there were some military changes that didn't make it into civilian production, although some ex-Air America 204's/05's did have them and entered civilian service with them. The most noticable and the one most engineers catch these days, were the oval shape of the holes that go up and down the door posts between the front doors and the sliding cargo doors.....on civilian models they were round. The outside and inside skin thickness was the other difference.


This is not pertinent to the question asked, but let's call it an interesting addendum to what Blackmac stated and he's "right on the numbers". His advice on where to seek that info that's being looked for is also "bang-on".

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I can't help in that regard. I was told at one time eons ago, but I've forgotten now. If that 1H had the oval holes then you can be absolutely certain that it was ex-Air America or an ex-Air Cav a/c. Some of the 1H's that Air America had were leases straight from Bell and a few were transferred over from the US Air Force. Any UH-1E's (204's) they had were all ex-USMC. They coiudn't destroy all the a/c they had because they owned approximately 4000 of every type know to Man. Many of the Bell leases were returned to a broker in TX and some of those made their way into Canada and are still operating to this day. On some of the UH-1B's there is a brass plate denoting their service to Air America. It's usually attached to the area of the inverters, down in the chin-bubble on the pilot's side. That would also be in the area of the c/b for the hydraulics which can be seen from the outside of the chin-bubble. "Finger-guides" or "channel guards" for the most the important switches on the console are also another "give-away" as to it's ancestery.......as in "Fuel On/Off and Hydraulics On/Off. Some have had thatremoved over the years by ownership, so the fact there is none does not denote that the a/c wasn't necessarily ex-Air America. "Miking" the forward bulk-head by the pedals is the "dead give-away" though.

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They didn't all have cross-swords. By regulation they were supposed to have it, but it was wartime and "certain liberties" are allowed. There was all manner of things on the nose including nothing. Ours had a skull, which was the insignia of our unit which was known as the "Headhunters". There was a lot of imagination went into the mounting of the door guns also and some "hot-rodding" went into the operation of those same guns. ALL sorts of "games" went on. :D


We've all had "one of those days" also........you'll have some more like those again in the future.......hang in there!.

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