HP limits on M20 Airframe??

[jetdriven]

Ususally flutter speed can be raised by increasing the mass balance on the control surfaces.  When the airframe  stiffness comes into play you increase the stiffness of the wing with spar shear webs, such as they did in the 1956 G35 Bonanza.  Its maximum speed was raised several times in its production cycle.

[Hank]

Quote: Shadrach

When did ground speed even come into the discussion??? The Acclaim is capable of TAS in excess of 240KTAS in level flight. much more coming down hill...

 

[Shadrach]

Quote: jetdriven

Ususally flutter speed can be raised by increasing the mass balance on the control surfaces.  When the airframe  stiffness comes into play you increase the stiffness of the wing with spar shear webs, such as they did in the 1956 G35 Bonanza.  Its maximum speed was raised several times in its production cycle.

[aviatoreb]

Quote: jetdriven

Because the M20TN flutter limit was raised higher than a M20K.  As far as his article goes, an RV-4 is an RV-4 is an RV-4. 

[Parker_Woodruff]

Quote: KSMooniac

[jetdriven]

the explanation is long, but it is true.  http://www.vansairforce.com/community/showthread.php?t=41255

 

[Shadrach]

Quote: Parker_Woodruff

[KSMooniac]

Quote: Parker_Woodruff

[John Pleisse]

Quote: Shadrach

[Parker_Woodruff]

Quote: N4352H

And this begs my question.... in terms of flutter, will the tail/stabilizer always be the weakest link?

[jetdriven]

Interesting is a 196 knot CAS at 25k feet is ~ 294 knots true airspeed!

[KSMooniac]

Quote: jetdriven

the explanation is long, but it is true.  http://www.vansairforce.com/community/showthread.php?t=41255

 

[KSMooniac]

Quote: N4352H

[KSMooniac]

Quote: Parker_Woodruff

And this begs my question.... in terms of flutter, will the tail/stabilizer always be the weakest link?

[Hank]

Quote: N4352H

[xftrplt]

-harmonics [remember the Verrazano Narrows Bridge?

I do, and assume it's just fine...but the Tacoma Narrows bridge no longer stands. 

[Parker_Woodruff]

Quote: KSMooniac

I'm speculating wildly here, but it very well could be that the FAA was less stringent with Rocket Engineering doing the STC substantiation in the early 90s (or whenever they did it) compared to Mooney developing the Encore in the mid- to late-90s.  They also used different Aircraft Certification Offices (ACOs) and the level of scrutiny varies considerably between ACOs across the country.

[aviatoreb]

Quote: KSMooniac

 My Encore Conversion has different counterweights than the original 252 (And Mooney charges a pretty good amount for them).  But the Rocket has the same counterweights as the original 252, if my understanding of the Rocket conversion is correct.

[M016576]

Quote: aviatoreb

 My Encore Conversion has different counterweights than the original 252 (And Mooney charges a pretty good amount for them).  But the Rocket has the same counterweights as the original 252, if my understanding of the Rocket conversion is correct.

[KSMooniac]

Quote: aviatoreb

Speaking from an after the fact analysis - has there been a problem?  Have there been any inflight breakups of modern mooneys each from J up, and also of the Rocket and Missiles?  Have there been any flutter issues that have lead to structural damage but perhaps no breakup?

There was a Vans around these parts that experienced flutter shortly after it was built about 2 years ago that suffered severe structural damage but fortunately no one was hurt other than in the wallet.

[jetdriven]

That k also bent the fuselage down as well as the wings.  It was a mountain wave accident and it was estimated at +/- 10G.   I read the mooney engineering report.  If it later showed up for sale, hey, it's just business.  Caveat emptor, right?   

[aviatoreb]

Quote: KSMooniac

ChrisH posted a report of a Rocket accident likely due to flutter above, which I had not previously known about.  I recall reading about a J that broke apart during a night IMC t'storm penetration in East Texas several years ago.  Those are the only known breakups to me, but I haven't done an extensive search either.  Both of those incidents started with bad pilot decisions and were not the fault of an airframe weakness IMO.  Few airplanes are built to survive every conceivable speed and atmospheric Wx condition.

I read about an account in a K (I think) somewhere around the Denver area that had a loss of control incident that resulted in a dive and a high-G pullup, but the pilot was able to land safely.  Afterwards the upper wing skins were observed to have been wrinkled and the insurance company scrapped the plane.  That damage was simple overload, and not flutter.  It appeared on ebay sometime later after getting "fixed" in Kentucky.  (draw your own conclusions here)

It is safe to say without reservation that there is no widespread problem with structural integrity or flutter with any Mooney airframe.

[KSMooniac]

Quote: jetdriven

That k also bent the fuselage down as well as the wings.  It was a mountain wave accident and it was estimated at +/- 10G.   I read the mooney engineering report.  If it later showed up for sale, hey, it's just business.  Caveat emptor, right?   

[smccray]

This thread makes my head hurt.

[KSMooniac]

Finance and accounting issues make my head hurt... aircraft engineering topics make me smile!