Va, Vso... VVVVVVVV

[Guest Maj Millard]

Hey I'm confused...Didn't the first guy ask about Va manouvering speed ? somehow it all went to Vne which is a totaly different kettle of fish. Simply put Vne (velocity never exceed) is the max speed that you want to stay away from, at all times, lest your plane could break, and you will die. (possible structural limit speed)

 

Va (design manouvering speed), also called on occasions 'best turbulent penetration speed' is that speed you reduce to if severe turbulance is encountered,so as to not damage the aeroplane. Yes it changes as the total weight of the aircraft changes. And yes if you are silly enough to fully deflect you flight control surfaces above this speed, you may also be in for an unpleasant surprise, as things break off around you.

 

My info is out of the Jeppersen Private pilot manual, and I also recommend a read of "Stick and Rudder" as he tells it straight also.

 

Also Youngmick...what basically made the Beech Starship unattractive to those who would buy such machines, is that it's total CG range was only 4" overall . This made every flight loading a math challange for all concerned. I did see one land over the top of me once, and it did indeed look very spacey however.

 

 

[djpacro]

Sorry Sqd Ldr, I'll get back on track with a comment on one of the queries in the original post.

 

"Of course, the aircraft designer may specify a Va speed that is greater than that minimum requirement."

Yes, the designer may choose to design the aeroplane for max control application at a higher manoeuvre speed than given by the formula in FAR 23. (refer 23.335 © (i) ) Raises an issue with the commonly regarded definition of manoeuvre speed being linked to stall speed times sqrt (design load factor).The same provision allows the designer to keep Va constant and not vary it as weight changes.

A fairly recent change to FAR 23 fixed that by introducing a new speed - VO (operating maneuvering speed) which is not greater than the stall speed times sqrt (design load factor) - refer 23.1507.

 

I've flown one or two aeroplanes where the maneuver speed is higher than Vs times sqrt (n) and they were certified prior to the introduction of 23.1507.

 

The sort of statement found in a flight manual offering guidance to pilots may be something like this:

 

"Full deflection of any one of the flight controls is authorized up to 146 mph, no matter if you are in negative or positive and with reservation that you are staying in the flight envelope."

Of course, this is not typical - that's the only one I've seen with the instruction that you must stay within the flight envelope regardless of being able to give full control deflection.

[youngmic]

Maj.,

 

what basically made the Beech Starship unattractive to those who would buy such machines, is that it's total CG range was only 4" overall .

Are you really sure about that or is this a wind up?

 

Not being able to out perform a significantly cheaper B200 might have been a bit of a set back to, don't you think.

 

 

[Guest Maj Millard]

Yes you are right about the B200 basically out-performing ,and as I remember it was a lot cheaper also. Not winding you up, the Starship did have a very narrow GC range for that catogory of aircraft. Although Elbert Rutan had married into the Beech family by the time the Starship was being developed, he probabily didn't have the time that he wanted, to put into the project. He had several other notable projects underway at the time, such as the Catbird, Grizzly, Voyager and other little projects that we were all treated too eventually, from Scaled at Mojave. I'm sure Bert would have been just as dissapointed as anybody, that the Starship wasn't a real commercial success. I'm sure the FAA certification process had a bit to do with it's demise also, not to mention Ratheyon who simply wern't prepared to support them from a spares point of view. Just so they wouldn't be liable for lawsuits once they bought Beech, they ended up buying most of them back and had them all basically destroyed. Wikapedia's wrap on the Starship makes for interesting reading also.

 

 

[youngmic]

But a 4" cg range?

 

I have a problem swallowing that one, hell my little Vari-eze has at least that range from memory (don't have the POH with me)

 

Canards are renowed for a large cg range.

 

 

[Guest Maj Millard]

Okay youngmic, don't say the major doesn't doesn't do his homework. Courtesy of a Mr Robert Scherer in the US, who appears to be well versed with Starships, I have in my possession the GC range and load chart for the Starship. Without wanting to present the whole thing, I offer the following.

 

Bottom of range: Wt 9000lbs 307 to 320 inchs Aft of datum Range 13" thats 6.5 inches either way, and as we all know it's always best to stay away from the edges.

 

Top of range: Wt 14,900lbs 310.9 to 320 inches Aft of datum Range 9.1 " thats 4.55 inches either way.

 

Hey, real sorry I was .55 out

 

The remainder of the range chart varies from between 4.55 " to 6.5 " either way, which for that size of aircraft, is pretty damn narrow in my book, canard or otherwise.

 

We drink beer up here, especially around Xmas, and it's usually XXXX Gold.

 

 

[youngmic]

Well I'd nearly pay that one particularly for the effort in doing the research and obtaining the facts.:thumb_up:

 

But something troubled me as I read your response, so I read it again and then I spotted it....

 

We drink beer up here, especially around Xmas, and it's usually XXXX Gold.

Your a bloody QLD'er and that explained it! See it's in your cultural history to confuse the basics, like electoral boundaries for example.

 

Does one describe an aircrafts range by the PNR, no that'd be silly, or a rifle range as the distance each way when one stands in the middle, no of course not, cept those QLD'ers maybe. Or the range of Cane Toad as somewhere between Cairns and the WA border, I wouldn't reckon so.

 

Below is lifted straight from Wikipedia so not gospel but it'll do for the purpose.

 

Center-of-gravity (or CG) limits are specified longitudinal (forward and aft) and/or lateral (left and right) limits within which the aircraft's center of gravity must be located during flight. The CG limits are indicated in the airplane flight manual. The area between the limits is called the CG Range of the aircraft.

Given the CoG range is between 9.1" and 13" within the useable weight range ( )

 

I see that you are in error by a factor of between 127% and 225%

 

Given that to be 100% wrong would constitute being completely wrong it would seem even at best that your worse than completely wrong and in the worse case of 225% you are so wrong that you may have even lapped yourself and be wrong twice and a bit.

 

Down here we drink red wine all year round ;)

 

Merry Xmas Maj :thumb_up:

 

 

[turboplanner]

Maybe we all owe you a bit of both for the entertainment!

 

 

[Guest Maj Millard]

Hey I don't know if I have ever been 225% wrong before, I might be breaking new ground here ?. Hey great answer, and of course you are correct. We do also polish off the odd bottle of red here , at least when we run out of beer. Merry Xmas to you also, and I am glad that we have entertained somebody out there.

 

And by the way I did get to view some really great video on one of the Beech Starship sites. (Google beech starship) Some great takeoffs, and one approach and landing at I think, Santa Fe NM, videod from the cockpit. Hell I wouldn't mind a ride in one now !.