upside down

So why fly upside down in a helo? Maybe because it looks cool i guess.
CFR

QUOTE: just trying to keep the site relevant to modeling. Plenty of chat boards and forums out there for pilots and helos as well. Since it is a modeling site, lets stick to modeling relevant issues.

QUOTE: By the way, all that Longbow radar junk, including the antenna dome, has been uninstalled from our birds. Especially now that it's getting hot, it's 600+ pounds of dead weight for the kind of work we're doing here.

I think that's the most telling thing I saw in this particular thread.......lots of OJT learned in OIF and OEF. Be safe, and hit them hard!!!

I've done some helicopter aerobatics work over the years. I work on Apache now, and the AH-64D can do loops and rolls within a reasonably tight envelope.

I was on the Comanche program for many years - it was fully aerobatic as well, but we never took the effort to qualify it to perform aerobatics. Problem was that the Army flight envelope requirement did not specify aerobatic capabilities, so Boeing-Sikorsky wanted more money to conduct the qualification. If we'd done it, we could have run the Comanche down the runway doing "aileron" rolls at 170 kts.

The BO-105 / BK-117 are fully aerobatic. The -105 had more capability due to its lighter weight. The -117 is just a bigger -105 with two engines and a larger rotor. The BK-117 tailboom is the same as the BO-105. I had a BK-117 we did some helicopter air-to-air work with in the early '80s. We did testing to document its aerobatic capabilities. MBB sent in their chief test pilot to train our guys. To get to the original question in this long thread, he used to do a routine in which he flew a BK-117 upside down in a straight line. I don't remember the airspeed. He claimed to be able to do it for 4 seconds, the limitaton being the fuel system, which wasn't designed to provide fuel in that attitude.

Was a prototype, never went into production, three were built the Army has two in storage(for the musuem), the third was acquired by NASA fate unknown(NASA may have it in storage for future display)

There is a beat up example of the RSRA in a hanger at Shell Army Airfield (outside of Rucker), minus wings and rotor system and covered in pidgeon droppings. It was huge, had ejection seats, and 4 engines. I can't imagine what use the army had for an aircraft like that.

There is a post script to the Ah-56 story...
As the program was winding down one of the prototypes was brought to NASA-Ames in Mt View, California for a round of wind tunnel testing. The halicopter was wired up and placed in the 40'x80' wind tunnel for the tests. As they proceeded to high speed portion of the program the AH-56 shuddered and dissembled itself (making a real mess of the tunnel) as aconsquience all remaining prototypes were grounded.

At about this same time our friends across country on the East Coast rolled out their anwser to the AH-56, the Black Hawk Gunship (name similar to the UH-60) the Sikorsky gunship was built around the companie's S61 powertrain. They toured the Army Airfields touting the helicopter as the low cost alternitive to the AH-56. A close friend of mine who drove Chinooks whitnessed one of the demos and said it was impressive.

Igor and company might have sold the machine to the Saudis except at the air show where they were going to ink the deal the Black Hawk crashed, the Saudis got cold feet and that was that. (Cause of the crash was dirt in the tail boom, which had entered through the nose.)

Back at Ames, the post incident analysis of the AH-56 showed that the high speed shudder and subisquent dissembly to the machine was a wind "tunnel only" accident because the machine was tied down, in free flight, the problem would have easily been corrected by the pilot. For Army Planners, Viet Nam was winding down, the Russkis and their tanks were the new threat, so who needs to go 300 mph in a helicopter anyway? Lockheed, countered with an offer to remove the the pusher prop and thus build it as a pure helicopter. But the deed was done.

For the Black Hawk the story continued, years later NASA would let a contract for the RSRA (Rotor Systems Research Aircraft flying wind tunnels) which Sikorsky would win and build two machines based on the S61 power train/and the Black Hawk. They would fly for many years before being retired... Last I heard the RSRA was still at Ames to place on public display.

Regards,
Chuck

Hey Jin,
Anyung-Ha-saeyo! Where in Korea are you from? I was born in the land of the morning calm and spent a few years in that great country in seoul and Pyongtaek.

Hay Jin
how are things in the ROK

sweet!

Ran across this photo last night while browsing through one of my books

Lockheen Model 286(N286L) goes inverted at the top of a loop. This a/c was using the Lockheed hingeless rotor system

Negative G's are quite bad in Helo's. Mast bumping, the rotor shearing off the tail or other important parts occurs.

In addition to the points listed above, it was more the politics of the day then inter-service rivilary that killed the Cheyenne(at least that's what my memory says)

Now I may be barking up the wrong tree here, but I thought that one of the reasons that the Cheyenne got cancelled was that its mission profile was infringeing on the Air Force's territory. eg high speed attack run well above the ground, behaving more like a fixed-wing ground attack a/c, as opposed to sneaking around and hiding behind trees and hills and such.
Mind you my source for this was an old retired AF guy, now deceased, so some service bigotry may be playing a part in this.

Roman

the cheyenne reminds me of a helo version of an A-10

That paint job was some weird foreshadowing.

What the H#!1 is that?

yep, the navalized AH-64 was one UGLY aircraft. Thankfully it never got past the concept stage. It looked like it had a giant banana grafted to the underside!

Someone built a model of one here:

http://s96920072.onlinehome.us/Gal3/2901-3000/Gal2986_CanAmConShow_DeLang/52.jpg

Back in the day when the Apache was first coming out Hughes(now Boeing) did have a Navalized model in mind, I can't remember if it was to be the B or C, but the Navy and the Marines showed no interest. A drawing can be seen in Squadron's "AH-64 In Action."

AH-64 vs. AH-1: There's also the question of marinization - folding, corrosion protection, EMC shielding, etc.

Maybe the situation hasn't arisen yet?...but the point is very valid.

As for why the Marines never went with the AH-64, there are probably a few, but the practical ones would be size and weight. The Apache is slightly heavier than the Cobra as well as longer. This affects the "deck multiple" of a ship, which is who many types of airframes can the Navy fit on a ship. The Marines also had just tested the AH-1T+ which became the AH-1W and could fire both TOW and Hellfire.

hmmm..... I think Don's got a point....

All this is well and good but why would you want/have to/need to "fly" upside down in a helicopter?
You can't fire weapons and you certainly cannot hoist so why bother?

Don

Hey,
I can't argue the time frame but I believe " the fix was already in " by the time
TD became prez. I standby my statement of the growth potetial as the 56 already
had a lot of what the "new" cobras have now.
I'm wndering why the Marines arn't buying the 64?
Grandad, Thanks for the pic! Very few major programs have not had fatals, The B-2
is the only one I can think of right now, that has had major tech inovations and
not crashed. But, yes I know those crashes didn't help just like the V-22 crashes.
well good night, er morning er wharever I'm going home to bed!!!!!!!!!!!!!!!!
Good Hunting,
G.W.

Have to agree with Jon on this. A couple of fatal crashes, cost overruns and development problems plaqued the Cheyenne and that's why congress killed it. In the end those lessons went into the Apache

rdxexpress,

No problem, man! Intelligent conversation is something that we thrive on around here.


Now, as far as your info on the Cheyenne goes, its a little (but not much) off. Firstly, the AH-56 was designed as part of the Advanced Aerial Fire Support System, which began in 1964. The Cheyenne beat out the Sikorsky and Bell entries hands down when it came to design. When the prototypes were finally built in 1967 (two years after the "interim" Cobra's rollout. The Cobra was already flying combat missions in Vietnam) they did perform rather well speed and maneuverability-wise, but had many issues regarding systems integration, drivetrain, etc.

The Cheyenne certainly had its advantages and it was a beautiful helicopter. But weapons systems integration, sensors and other issues plagued it throughout development. By the time those kinks were worked out and it was ready for production in 1972, the AH-1 had been in combat for four years and had shown an extremely high degree of adaptability.

As far as politics go, I guess you can make that claim, but Bell had the product ready to go in 1965, whereas Lockheed took another seven years to have it ready for production.
The point was, " our guys were dying in Vietnam now. They weren't gonna wait years for a new helicopter." I don't think that's a political decision at all. Seems ultimately practical to me.

The Cheyenne became a fantastic technology demonstrator and we learned a lot from it through its flight test program. The rigid rotor system worked well, but by the time we were looking at replacing the tried-and-true Vietnam-era birds, we were looking at much more efficient fully-articulated rotor systems. As to it having more growth potential than the AH-1, I politely disagree. If the AH-1 didn't have that kind of growth potential, the Marines wouldn't have just ordered brand new AH-1Zs.

The Cheyenne and now the Comanche are fantastic concepts and extremely capable machines, but when it came down to it, they were just not what the Army needed. The Army needs Attack helicopters that can put ordnance on the bad guys, not get stuck in development for a decade, waiting for that last bit of technology to make it perfect. Furthermore, the AH-56 was cleared for production in 1972, during Nixon's presidency. Both Nixon and Lockheed are California products, so using the political angle, you've just disproven yourself.

The AH-64 was developed from lessons learned primarily from the AH-1 in Vietnam, but also from information gleaned from the AH-56 program. The combination of the two produced a superior attack helicopter that went from development to full scale production in what has now become a relatively short period of time (1977-1984)

I for one am certainly thankful for both programs. When I finally get behind the controls of an Apache for the first time next spring, I will be benefiting from all of that knowledge and experience. Can't ask for more than that!

Ah, the dreaded "P-word" - the same reason the V-22 is still around today. Very good point you've made.

Hi all,
Seems I stirred the pot a little! The Cheyenne would have been the next (first true)
gun ship had not politics become involved. Remember WHO was president and where Bell was based. The developement costs where high and surely didn't help
but there were no problems that couldn't have beed solved in the long run we( the
taxpayers and pilots) would have been better off, because there would have been
no need for the '64 and its devolpement costs . Sorry CH I don't mean to hurt your
feelings, the Cobra was a good choice for a stopgap as it did share drivetrain with
the HUEY which did/would help supply but that was about all. The '56 had a lot
more growth potental then the Cobra was faster and could carry more.
Yes I am particial to the 56 as CB is to the Cobra. BUT LBJs from Texas, He's a big man of distinction................
Good Hunting
G.W.

I only flew RC helo's on the sim, at a thousnad bucks to start, they were too expensive for my blood. As a comparasion, I think it's harder to fly a RC model then the real thing because you can't feel the movement of the a/c(only stick time I have in a real helo is what I could get off the pilots)