Having recently read Giovanni de Briganti’s comments in the above article he does cut to the chase covering a number of issues ("Chinook Downwash and Other Failings" December 2008, page 62).
Before I comment on a few items, I would like to clarify a common error that is made with the vernacular when discussing rescue operations.
Mr. de Briganti refers to winching in the article which should read "hoisting." A device such as a rescue hoist is used in a vertical mode and its resultant action is called hoisting. "Winching" is done in a horizontal mode and refers to winching in cargo in a stiff-winged aircraft or helicopter. This is a common error when referring to such an operation. As we all know, some helicopters have both devices installed. And yes, I do know, the Brits call it winching!
Downwash is always an issue, greater for some than others depending on how high the altitude during recovery. The MH-53 in SEA had the same problem, was a great machine but wasn’t a political football as the MH-47. It did the job and damn good too! In the current theatre of operations, show me something that will do the job the Chinook does over 10,000 feet. As a combat SAR vehicle it should be looked upon as a long-range self sustained vehicle for any theatre of operation. It may not be the perfect vehicle, there will never be. It could use a larger door but the one on MH-53‘s wasn’t any bigger. The rotor wash is a bit greater but so it was with the MH-53. I think Mr. de Briganti isn’t considering is the fact that the MH-47 can go farther, faster, higher and quicker in effecting a recovery of more personnel than current vehicles can, which I feel is the SAR philosophy for the future. You gotta believe, "big is better."
Paul R. Kopczynski Union, N.J.
What a pleasant surprise to read the December 2008 issue of Rotor & Wing! Please pass along my thanks to Mr. Prouty for answering my questions ("Sikorsky’s Black Hawk in Autorotation" December 2008, page 60).
His statement, "the advantage of having a lower rate of descent due to a high gross weight is slight," is exactly what I was looking for (from an operational perspective).
Apologies for the confusion of the second question. A lower descent rate during the autorotation certainly provides more time for predicting control inputs for the flare altitude and rate, which is good. I was leaning more towards the following (which I think he covered in his answer): from the point of the flare to touchdown, the probability of a safe engine-out landing in a lighter-weight helicopter is greater than in a heavier one. To any pilot, that statement is pretty simple and obvious. A lot of factors, of course. In terms of physics, I believe that total momentum becomes an important factor in how well things go. The heavier the aircraft, the more it will take out of the rotor to slow vertical and horizontal speeds and to cushion for landing.
I will consider writing a clarifying note to the R&W editor on this, but only after some feedback on the above.
Part of my efforts this past year have been in trying to explain H-60 autorotation flight characteristics, training, risk management, and emergency procedures for autorotations for inclusion in the Navy’s NATOPS flight manual. Attached is my input.
Sid Hatcher Patuxent River, Md.
Keep Your Chin Up
I do trade press PR for a global company that makes products for more than a dozen different markets, so consequently I subscribe to and review several dozen industrial trade magazines each month. I’ve been engaged in this since August, and every month, I’m struck by the similarity of the Editor’s columns. Woe is us, they say. We’re doomed. The sky is falling. So I was refreshed today when I picked up Rotor & Wing and caught the positive, optimistic tone of your message on spending. Thanks! Great message, and cleverly written as well ("The Three Little Angels of Spending" January 2009, page 4).
Understandably, everybody’s looking for the magic crystal ball these days to divine how long the financial crisis will last, when the stock market will rebound, when will our 401Ks catch back up to previous levels. We hear talk that this may be the worst economic malaise since the Great Depression, and the intimation is that we may even sink to those depths.
You say you’re no economist, Ernie, nor am I, but my suspicion is that the real wealth of our nation has so greatly increased since 1940 that to compare our plight with that of the 1930s is really dishonoring to the individuals who struggled to survive the Depression.
Of course, there’s no place for Alfred E. Newman (What, me worry?) and it won’t help to grow ostrich feathers. But the fear-mongering we hear from the network talking heads is equally damaging. With a little maturity, a bit of conservative wisdom and a little entrepreneurial chutzpah, perhaps we’ll get through this with only a few bruises, and we’ll look back someday wishing we hadn’t been such hand-wringers.
J.B. Freeport, Ill.
Do you have comments on the rotorcraft industry or recent articles and viewpoints we’ve published? Send them to Editor, Rotor & Wing, 4 Choke Cherry Road, Second Floor, Rockville, Md. 20850, USA, fax us at 1-301-354-1809 or e-mail us at firstname.lastname@example.org. Please include a city and state or province with your name and ratings. We reserve the right to edit all submitted material.