Question on the CH-46, 1968

[Sparrowhawk]

During operation Rock, two platoons from India Company 3/7 were picked up by six CH-46's from An Hoa and dropped off at the northern tip of Fingerlake, the old Arizona territory, just south of the Sung Vu Gia River

Later they pick up, Lima and hotel company at on Hill 37 and dropped them off further north of us.



If I remember right, when we first landed we were hit as soon as we landed, it was a hot LZ.

What I don't remember and this may seem as not important after all these years, but when we landed, If I remember correctly the back ramp was already opened?

Was this common practice or did we land then the door flew open, it seems like we landed and we were out that rear door right away. If not how long does it take or did it take for that ramp to be fully opened for us to get out?

It seems like sometimes it took forever and at other times as if it was opened before we landed?


Or have I just forgotten something here?

Just one of those things in the back of my mind.

Semper Fi

Cook Barela

cookbarela@hotmail.com

[Joe Reed]

I doubt it! Boeing Vertol Would have a hissy fit if we flew with the ramp down in a CH-46. Weakened the rear too much, too much stress. The CH-47 would handle it, I'm told but never a CH-46. Us Crew Chiefs or whoever had the responsibility, would open the ramp POST HASTE to get you guys out as quickly as possible. We wanted to get out of the zone where we were most vulnerable, FAST! As soon as I felt the main mounts hit, as I cleared the pilot, I put the ramp down or ordered it down as the case may be. Some were quicker than others. Hope this helps.
Semper Fi
Joe

[timothy]

I can see where the aft ramp could be a structural concern, but we (HMM-262 66-67) operated what we called a slick for heavy lifting. It had the aft ramp removed and other things to shed weight. I don't know if it was blessed by Boeing; but we did it.
Semper Fi,
Tim McMahon HMM-262 65-67

[Ray Norton]

On a no hover approach to a spot, the pilot should lower the ramp using his or her left hand. By holding the spring loaded ramp down toggle while at the same time engaging the ramp hold toggle the pilot can get his or her hand quickly back on the collective. The ramp will continue of its own accord. Reverse the process to raise it.

Start lowering the ramp after hitting ground effect and feeling the need for less power.

Smoothly but rapidly continue the landing to a no hover touchdown. As the main mounts hit, smoothly lower the nose wheel so that the aircraft is firmly and quickly on the ground. No hover is allowed. No forward motion is allowed. Landing with the brakes on is a good idea, but I often applied them upon touchdown.

If done properly, the ramp will hit the ground just seconds after touchdown.

If done improperly, you will scrape it, bend it, and get your ass chewed out by everyone from the crew chief to the wing CG!

On takeoff, raise the ramp using the toggle swiches described above. Wait two seconds, then lift the nose wheel. Next get the mains free for a six inch hover and get out of there. The ramp will close of its own accord on climbout.

It looks really cool from the ground!

[Joe Reed]

Learning new stuff 38 years later!! When we di the "Buttonhook turn landings and similar to "hot" LZs we would usualyy come in fairly nose high as I recall, until the last few seconds. Then we'd drop the nose, smoothly but quickly and we were on the deck. If I had dropped the ramp early we'd have bent it for sure. Clearly different squadrons had heir own procedures. Guess they must've worked judging by the number of us talking about it. I don't remember a spring loaded ramp toggle, although I'm sure ray is correct, maybe the "Alphas" weren't so equipped.
When you flew "A" models you got in as fast as you could, because you knew you weren't gonna get out quite as fast as you wanted! maybe if you sneaked by the little suckers on the way in, they'd miss you on the way out, LOL!
Semper Fi
Joe

[Ray Norton]

Joe:

You've almost got it! Sixty degrees nose up to slow down works fine. When your airspeed drops below 70 knots and you lose translational lift, switch to hover aft and/or the automatic feature switches for you. The nose comes down as you described.

At this point, provided you are close to the deck, the ramp can start down with proper timing.

I would recommend this maneuver only for a prepared LZ or runway.

This was never a procedure I was taught, I just figured it out on my own. After all, pilots have to have fun and look cool!

[Joe Reed]

As a Crew Chief/Mechanic I didn't get to practice any button hook turns or landings, although I could do a roll on pretty well in an "A" model by the time I left RVN, Thanks to Eddie Fischer, J.J. Smith and some other generous Test Pilot/HACs from HMM-165 back in the day. Took me a bit to get used to the "F" and the power, but I did get to fly them some as well back in CONUS. In HMM-163, Rock Darger got me up in the LTA pattern pretty quickly after I tried to land about 200 feet short of the runway the first time (got a little nose high) and he fixed me up pretty fast. Sure don't have to push down on the cyclic to get the nose down on the "F" like you did on the "A"'s when you need the airspeed!! Damn "F"' almost did a sommersault the rear came up so fast... That's what I meant by gettin' OUT of the zone faster in the "D" models that in the "A"'s!! LOL! The automatic "hover aft" is pretty neat too. Can't button hook with it, but that's probably a good thing, according to the Tech Reps, LOL! Less airframe stress!
Enjoyed it, Ray!
Semper Fi
Joe

[Sparrowhawk]

Ray Norton "It looks really cool from the ground!"

Must admit, it looked good when you guys took off, remember seeing those tails lift up and the chopper traveling that way for a few yards and wondering when you guys were going to get the front end up, when you were taking hits on a hot LZ.

Sometimes those ramps seemed to take forever, to come down but it’s been so long that sometimes I only see the ramp, and have forgotten if they were Mike boat ramps or the ramps on the CH-46's.

Often in a hot LZ the crew chief or someone by the ramp would point us toward an area we should head toward, or where the incoming fire was coming from. During Operation Rock, before we landed we were taking hits from two sides, and I looked at him for suggestions, and he looked at me, and just threw up his hands in the air, he didn't know. Have never forgotten that expression on his face.

And it wasn't me, it was tired Aggie, my A-gunner on the M-60 that took those cool sunglasses from off the crew chief's seat before he ran out the ramp.

He said, when you guys return to pick him up out of that mess he would give them back. LOL


Thanks guys, for coming back to pick us up and for answering these questions so many years afterwards.

Semper Fi

Cook Barela

Vietnam Diary 1967-1968

[jejacobs]

I recall a specific Recon insert briefing in which we were instructed to keep the aft ramp somewhere between horizontal and the full "up" position, because we would be making several false landings before inserting the Recon Team into the Ashau Valley. If we kept the aft ramp in that postion, Charlie and/or the NVA would have a harder time figuring out which landing was the real LZ.

Once we we in the air, I lowered the ramp. After making a couple of "false" landings, just barely touching the aft struts on the ground, we'd be off again. Then, just before hitting the designated LZ, the team members would huddle up at Station 410. As soon as the aft gear touched down, they were out and we were airborne to do a couple more of the false landings. Finally, only after departing the general area, would the pilot or crew close the ramp completely.

I never did have a damaged ramp, but then, although there are always exceptions, we had some damn fine pilots -- would do it again, too, but they don't make flight suits out of Spandex! Heck, who needs a flight suit -- let's go!!

Happy Memorial Day to all --

[timothy]

I seem to remember a pressure relief valve in the ramp hydraulic system to prevent damage to the ramp.
Tim McMahon HMM-262 hyd. 65-67

[Roger Thaht]

The ramp of yesteryear is different from today. Now the ramp and hatch control manifold has controls fluid to the ramp and hatch at 750 psi. Back in the day it worked at the 3000 psi but pilots kept crushing people so the pilots control panel works at 750 psi only and they are spring loaded switches. The crewcchief can push a springloaded switch witch bypasses the pressure regulator and can drop up to 3800 psi (max pressure of utility hyd system) on the ramp, its bad for the actuators tho.

[dchurchin]

Having flown paraops in an H-46 and having jumped out of a perfectly good one, I can attest that the ramp can be lowered in flight without structural damage. Don't recall any limits.

[Ray Norton]

From NATOPS Flight Manual CH-46D/F, UH-46D
1 October 1975 w/ change 33

"Fuselage structural strength is not dependent upon ramp position." (Page 1-119)

Exactly how much the ramp can hold is left unstated. It was originally designed to allow pallets and vehicles to load as well as troops. However, the original mission did not anticipate paradrops and some of the other tasks that have been assigned. It would seem that a weight limit should have been stated.

Sometime in about 1968, an airframe change involved a special connection for a pulley on the door over the ramp. This created the possibility of hoisting over the ramp rather than the cargo hook hole ("hell hole"). This change enabled bringing the NASA astronaut basket aboard since it did not fit through the "hell hole." I always thought the best way to hoist was through the cargo hook hole. I never saw or used that new-fangled hoist that was installed beside the crew chief's door. I always thought it must have been sold and designed by Sikorsky!

[Joe Reed]

It wasn't being lowered in flight that I was refering to causing the damage, it was landing nose high with the ramp already down that would've damaged it. I guess there was a "fine line" there that had to be maintained.
I had a transitioning field grade land on a stump with a ramp partially lowered that put us in the metal shop for a while, so I guess I'm a bit sensitive to to it. I'm intrigued by the other descriptions I've read here. Must've been a dozen ways to do it all!
Semper Fi
Joe

[Walt]

The orders for the slicks has Tim called them came from MAG36,after leaving Ky Ha and joining MAG 16 we no longer had any slicks. ET 35 was one of the air craft that the ramp was removed from. The aft pylon departed ET35 31 August 1967 killing ever one aboard. I think it was the straw that broke the camels back because shortly after that all the 46's where grounded except for ermergecy's. Soon after 262 went to Okinawa aboard the Tropli with 53 46's for the MOD program.

[Joe Reed]

Walt,
I think that ended the "rampless" '46 flights, at least the "A" model ones. John Dulligan told us in no uncertain terms, NO WAY! Weakened the structure too much!
How do you remember all those dates, Walt? You are amazing!
Semper Fi, Sir!
Joe

[timothy]

Joe,
Walt remembers everything! He has a great storage bank in his head, with all the details. I don't remember him taking notes, he didn't have time for notes. Walt was a Gunny back then and was busy keeping us working hard, and we played hard. Walt and his fellow SNCO's were great leaders!
Semper Fi,
Tim McMahon HMM-262 65-67 RVN 66-67