Aux Power Units on the 46

[Tom Thompson]

Can one of you crew chiefs give me the skinny on the aux power units? Where on the aircraft was it located, what type on engine. What was the starting and shutdown procedures? Picture or directions to a procedures manual.

[Tim Bastyr]

As I recall, the units on a 46 were actually refered to as APP's (auxillary power plants). The units on H-34's were APU's. The APP was a small turbine engine located in the rear of the aft pylon, just above the fuselage (rear cabin). The APP was an electrically actuated, hydraulic started unit. In other words, a release of hydraulic pressure would turn the unit, which would ignite at a predetermined RPM ( I can't remember what % of turbine speed that was). One of the worst sounds was the APP winding down after a failed attempt to start it up. That meant working up a full sweat by hand pumping a hydraulic accumulator to get enough pressure to attempt another start. the APP powered a generator and hydraulic pump which would allow the aircraft to be powered up, but did not provide electrical and/or hydraulic power to all systems. How's that for not having touched an APP for 37 years?

Tim Bastyr

[Joe Reed]

Pretty good Tim! We had to watch the temp as we lit the APP off, if all was okay we let it run. Never did have one over temp, or ever hear of one. Once the engines were up and the blades were turning, the electrical system was on line, we would then shut down the APP and run on generator power from then on. When we were completing a mission and taxiing back into the revetment, or parking spot we'd fire the APP back up to complete the shut down procedures, fold blades if needed etc. They were pretty tough old deals. Hope this helps.
Semper Fi
Joe

[Mike Mullen]

"Ready Ape"?

....how many times did we ask each other that question?

Moon

[Tom Thompson]

Thanks for the response -

Are you by any chance the same Moon Mullins that flew for
Detroit's Finest?

[Wayne Stafford]

APPs are now being refurbished and used to power homebuilt helicopters. There's a conversion for the Rotorway and the Helicycle comes standard with one. Also, Solar Turbines is located on the approach to Lindbergh Field in San Diego.

The APU in an H-34 was a Homelite chainsaw motor and a motor/generator as I remember. Talk about high tech.

[pm3777]

I figure the CH46 probably had the same t62 as was in the CH53. It was started by the hydraulic charge & had the pump handle in case you lost the first charge . It ran the acessary GB for electrical & hydraulics. I was just reading in the Feb 04 Kitplane magazine where the T62T32 is being inastalled in the RotorWay 2 place helicopter . It produces 180 HP and they said it was originally ordered by the Gov for a proposed two place helicopter. SF PM

[Top A]

Rhat awful wind down sound and that meant pimp back to I think 2500psi about 54 pumps if memory recalls. Most sqds maint guys said if it works leaveit alone or it will break.

Tom would Detroit's finiest be Hmm-768 at Selfridge aaafb/angb?

[Tim Bastyr]

Wayne, I'm surprised that the H-34 APU engine was a Homelight chainsaw engine. You can usually start those chainsaws. Can you remember trying to start the APU with a pull cord? You are right, real high tech.

APU trivia: What was the intended function of the APU?

Tim Bastyr

[jdullighan]

Attached is the entry in the Natops Manual. The next post shows the circuit diagrams for the hydraulics and the AC power.

The APP itself was pretty reliable. The only failure I remember was at Camp Vandegrift and of course, it was late in the day. The power turbine rotor, which looked like a small impellor attached to the shaft and held on by a nut, departed, never to be seen again. Vandegrift was not a place one wanted to RON. There were, of course, no spare units and the first thought was to take a known good unit from another airplane and install it in place of the failed APP. But there really wasn't enough time to do that in daylight and working up on the aft pylon with lights was not an attractive thought.

So I took a look at the hydraulic circuit diagram in the maintenance manal and concluded that if we hooked up a ground cart there should be enough pressure to start the engines. (Hydraulics was my engineering field so I hoped I knew enough to stick my neck out. But this is not necceesarily true). Anyway, we got a ground cart, tied it down in the back of an H-46 and took off for Vandegrift. We did have the sense to test the ground cart and make sure it ran OK. Half way there, when I'd calmed down from persuading the maintenance officer, the CO and most important, the NCOiC, Hydraulics that using a ground cart was feasible, I realised that we should have tried it on an airplane at Marble. Well, too late now. It was getting dusk at Vandegrift when we arrived, hooked up the ground cart, ran it flat out and started up the engine. My heart nearly stopped when the engine RPM seemed to hang up (I noticed later they did that but it seemed like 10 minutes instead of the second or so). Then it took off and fired up OK. Of course, I knew it would all the time. Right!! Hero instead of Goat. For a short while anyhow.

[jdullighan]

These diagrams go with my other post

[timothy]

Tim Bastyr is right the APP was hyd. started by the APP motor pump. Best started if the accum. had 3000 psi, which went through the app start valve. A bad start valve would let the accum. leak down to the 1500psi precharge. They would leak often and were a pain in the butt to change! That's where your bubble chasers got the pink tee shirts from. It was the 1st rags job to pump it up. A good bubble chaser could get one started with no hyd. press. we were fast pumpers! Finding leaks onboard ship at night was a tough job with a red flashlight. What a job!
Semper Fi,
Tim McMahon HMM-262 hyd. 65-67

[Bob Quinter]

Part of the preflight was ensuring there was sufficient pressure in the system for APP start. If you had a no start the pilot who checked the pressure assumed responsibility for pumping the pressure up for the next start.

[jejacobs]

I'm surprised that nobody has yet to mention what happens:

a) when the "FNG" copilot would hit the APP start switch BEFORE asking the Crew Chief if the APP had enough pressure to start the "APE"....

b) when the FNG copilot would hit the start switch and accidentally switch it back off....

c) Switch it on then off again when he realized that the pilot had not yet given the order to "Start APE"....

In any case, the Crew Chief had to scamble from where ever he was to get to the APP pump handle, before the pressure was drained off, pump his guts out to get the hydrualic pressure back up to an acceptable level which would produce enough revolutions to fire it off and flop on the aft ramp completely exhausted.

However,bug-eyed, sweat pouring down out of his helmet, arm hurting like Hell from the over-exertion, chest wheezing like an old accordian, just barely enough oxygen to survive, a good Crew Chief ALWAYS had enough breath ledft in him to utter:

"...!@*#$%^& -- FNG!..."

Aaaaahhhh, sweet memories of youth - those were the days.!!!

[Ernie Needham]

Tim,
I'll have a try at your trivia question. They were installed for running the heater without having to run the engine. The cold weather kit had a lot of ducting and covers. With 24 helicopters it was a real storage problem for something that was never used.
S/F
Ernie Needham

[Joe Reed]

John Dulligan is the "King" of CH-46 knowledge, no question about it! Hand him the crown now, don't waste any more time! Great post and info, John! Thanks for your input.
Semper Fi
Joe:rolleyes:

[Larry Zok]

Joe

John better have his collective stuff in one bag. He was a Boeing Tech Rep on that bird. I hope he knows what in the h*** he is talking about!!!! Met John at the San Diego airport on his way to his first Popasmoke Reunion. He had a great time and contributes to a lot of different forums. I, for one, am glad he found us!!!

SF John

Larry

[jdullighan]

Thanks Joe but Norm Clark is King and Emperor in my book. I'll take Crown Prince if only because I can read.

When I left Boeing my boss, Jack Geier commented that Tech Reps coming in from the field passed through a zone where stuff was stolen - but only thngs like Natops Manuals, Company reports and flight gear which seemed to reappear later when the guy had left the company.

Ps: "Ready Ape" has nothing to do with the appearance of the crew chief.

[Tim Bastyr]

Ernie Needham wins the trivia question prize! Gee Ernie, I didn't think that anyone would remember that the intended purpose of the UH-34 APU was to run the heater. For those that lack your exceptional memory, the purpose of running the heater was to pre-heat the engine and transmission in cold weather.

I cannot remember ever actually using the APU for that purpose. In fact, the only time I ever saw the APU used was to start the engine in the case of a low battery charge. That really took some tinkering to accomplish. Every time the pilot cranked the engine, the APU would stall.

S/F
Tim Bastyr

[Joe Reed]

Larry,
He was our Tech Rep in HMM-165 when I was there in 1967-68! I know from where I speak. King or Crown Prince, he can fly with me anytime he wants, any seat he wants!
Semper Fi
Joe

[Ernie Needham]

Tim,

Thanks for the grand prize. I never saw the ducting used either. I do recall when I was a member of HMR-362 and we took our HUS-1 (H-34s) out to Oppama in 1959 aboard the USNS Core.
The R&T (Repair and Transfer) group at North Island did install all the covers. Which were blue by the way. They didn't match the Marine green very well.

S/F
Ernie Needham

[Walt]

Cheap Oppoma Marines now that brings back memories.

[Ernie Needham]

Hi Walt,

Yes, lots of fond memoires also of Oppama. Without doubt I think it had the best mess of any I ever attended. HMR-362 was the second squadron to take the HUS-1 to the Far East. I think 262 was first. When we arrived in May 1959. HMR- 262 was in Korea on maneuvers. When they returned it got very crowded with that many birds parked in such a limited space. As I recall most of the helicopters had to have blades folded. That was okay, good practice for the ship. HMR-262 soon departed for Okie. We, along with a few remaining members of the MAG departed Oppama in March of 1960 aboard the USS Princeton. Sad day indeed.

S/F
Ernie Needham

[pm3777]

Ernie talked before about your father & uncle being in the Corps. I have a group photo of AES-41 back in late 40ies with picture of E. Needham CWO expect that was your father. Do you have this ? If not will have a copy made & send it if you give me a mail address. I remember well the App on the UH34 and the rope a dope to get it started. Also as to the heater in hot weather the sensor would automatically start the fan in the heater. As for 1820-84c engine changes we at VNAF averaged engine changes at 200 hours or less. Mostly from panic overspeeds or overboosts. When you were being shot at the trottle advanced immediately!!! On filters or EAPs dont know if you were on the CH53 but the EAPs doors were closed until take off when you reached 60 Knots a sensor closed and opened the EAPs doors. I chased down a problem where at 60 Knots the helicpoter jumped and the hyd systems dropped momentarily. This happened for years & all kinds of theories didnt solve it. But I finally found only one thing was common to both Generaters . That was the common ground on the transmission deck. The cause was the EAPs doors drew the highest Volt/Amp load of anything on the Helicopter. Had the maintenace folks pull the ground bracket & found that it had been installed on all CH53 as a dissillar medal installation VS a ground base. Result was the AF change where they were cleaned of the insulation material & bolted VS rivit to the transmission deck. Enough already!! Semper Fi PM

[Walt]

Ernie it was 261 and that was my first helicopter squadron. Sf Walt

[timothy]

Just shut up and keep pumping!
S/F
Tim

[G. Larry Larkin]

When we tired of common terminology - we changed to
"READY GORILLA". Refering to the aircraft systems, of course, and not to the Crew Chief.

[Roger Thaht]

i dont know why anyone would want to be in a helicopter powered by the 46's apu. It is made by international harvester and was originally designed for water irrigation. BTW they make 65 shaft horsepower, burns 92 lbs per hour of fuel. and becomes self sustaing at 90%. They are tricky little ****ers, more tempermental then a gunny could ever be. BTW, If someone could tell me about the cabin heaters backin the day i would appreciate it. Is it true they used to insulation in the cabin and panels over the wires?

[Tom Thompson]

Still Hummin

[timothy]

I spent a lot of time back there! Always changing APP motor/pumps.
S/F
Tim

[jrmonroe]

FNG just out of Ops school in Memphis was assigned to HMM-365 S-3. After all the mechs sent the new guy that just wanted to help to group for a couple yards of flight line or the bucket of prop wash.....I wasn't gonna let em get me with the ape thing.

We live and learn!!!

[Joe Reed]

James,
Don't feel like the "Lone Ranger" there. We all went through that, and I even did it at HMM-365, New River, same as you. I was just a couple of years earlier, in 1966. After the flight "line" ordeal, I was sent all the way to the H&MS hanger for a bucket of "prop wash"!! LOL!! That was when '365 was all the way at the south end of the "new" hangar!! What a hike that was!! I was NOT pleased when I found out it was another joke and went looking for the prankster that sent me on my wild goose chase, but he has high tailed it when he saw me coming with steam rolling out of my ears! It was all part of our "initiation" into Marine aviation, from the ranks of school/training. After that WE were the ones sending the "boots" off for the silly stuff!
The "Ape" is a real deal though. Actually a synonym for APP (Auxillary Power Plant) we've been calling them "apes" for years. You're indeed correct, we do live and learn.
Semper Fi
Joe

[John Hodge]

Wow! Reading through those posts sure brought back memory, recognition and some laughs!

That picture from Tom Thompson showing the APE sure looks familiar. I was a bubble chaser on 34s in New River, 46s in New River and most of the time elsewhere. In-Country I was on 53s then back to 46s. I remember working on a 46 aboard LPH 10 or 11, I was on both and don't remember which it was now. Anyway I was up there on that tiny a$$ platform working on or changing a pump, or bleeding it, or something in rough seas. The bird was parked, tail over the deck, when the boat hit a big wave, my hands were wet with water and Hydraulic fluid when I dang near fell off that platform, which would have been "Man overboard". Anyway I caught myself, cut my hand up in the process, and managed to get down off that platform safely. I don't remember ever going up there again in bad weather, aboard a ship. I don't remember for sure but I think I changed out of wet clothes when I got back to my quarters. I'm not sure all the "wet" was just water either. Whew!

Man, I sure remember the pink T-Shirts too, and yes they were Pink for the very reason mentioned above. Oh, and as memory serves the APE pressure was 3000 psi.

Isn't it a surprise we survived our youth?

[airhmm265]

i concurr with all of the very knowledgeable c/c that ever had to
pump that little handle ....... FNG"S both pilots and 1st rags learned fast
about the start switch ha ha .... i had a great 1st , long armed irish red headed kid ...... by the time we left he had muscles
on his muscles..... but enough fun the heater and ducting
were removed when we hit in country ...disconnected fuel line
to heater up on top in front cowling... ripped the insulation out also so that nothing could get left be hind it ....

MAYBE THE NEXT TIME WE GET NEAR ONE. WE CAN SEE WHO CAN PUMP IT UP FASTER OLD PILOTS OR CREW CHIEF LOL

[Top A]

LOL on the Yards of flight and bucket of prop/rotor wash. Most all of us did it had or watched it happen. But once in a blue moon a Smart ^&* would find an Air Force and get the real Prop Wash, There really is a stock for it.

[Tom Thompson]

Greetings Top -

Sorry I didn't reply to your earlier question about Detroit's Finest.
I didn't see the question until todat when I was scrolling up throught earlier posts. To (finally) anwser your question:

When I got out of the Corps, I went to work for the Detroit Police Avaition Division crewing on the helo that they were using for the Harbor Master. Oddly enough, we had a pilot named Moon Mullins - quite a character. I knew he had flow helo's in the military - he was pretty mum on the subject, so I never pressed it. When I saw our Moon Mullins reply on a post, I had to ask.

As far as SANG (Selfrige Air National Guard Base), I drive past the perimeter road every day on my way to work. Never see any helo's - it's all F-16's, C-130's & C-141's. There's been a big push for years to shut the base down. Valuable Real Estate -

Semper Fi

Tom

[Tom Thompson]

What a hoot !!

We had some wise acre's that had us going from squadron to squadron searching for "Frequency Grease"

[jejacobs]

About a million years ago, in early 1967, as a 19 year old Crew Chief, we were somewhere South of Ky Ha, RVN and took a round in the aft pylon area, near the aft transmission. While still in flight, I dropped the aft hatch for a quick look and oil came gushing down. After slithering myself up the oily aft hatch, with the help of one of the gunners, yours truly immediately concluded that we had taken a round in the aft transmission - because the oil level in the glass gauge showed ZERO! The Pucker Factor rose to MAXIMUM effect, at which time I informed the pilot, in no uncertain terms, to set her down NOW before we became a large green brick.

Once on the ground, in an area we were not sure was friendly, with engines and rotors shut down, that darn gauge showed FULL! It was then that we discovered that what had been hit was the oil reservoir of the APP. Now with no APP and no engines, how do we get out of the zone? The REACT team had to come out with another APP.

For the past 30+ years, every time I see GYSGT Walt Jones, Line Chief, or SSGT Otis (Big-O) Felder, the REACT Team Leader at that time, they always asks me the same question, but now they do not use all those colorful expicatives that Big-O used when he arrived in the zone that day

Big-o: ''Son, what does the aft transmission oil level gauge show when the transmission is engaged?''

Me: ''It always shows ZERO!"

Big-O: ''And why is that, Son?"

Me: ''Well, because the oil is swirling around in the transmission when it's engaged''

I must admit that I honestly welcome the good natured ribbing from my old friends, especially considering the possible consequences from taking a round in the aft transmission that day.

[Top A]

Tom thanks for reply late as maybe. SANGB deactivated the HMM and VMO moved to Alanta, Ga in late 70's Had 34's, 46's and OV10's when I was there oh and GySgt Otis Fielder.