[DanH]

Anyone have a copy (electronic or otherwise) of Aircraft and Equipment Engineering Report No. 45?

There may be supplements....I see this in a biography:

Rosenbaum, Robert: Simplified Flutter Prevention Criteria for Personal Type Aircraft. U.S. Civil Aeronautics Manual 3, Equipment Engineering Report No. 45, Supplement No. 11, 1952.

 

[bkilby]

Just googled it:
http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA955270&Location=U2&doc=GetTRDoc.pdf

 

[rvmills]

Dan,

Copy of it here. Its a bit slow opening, as its an old archive copy.

On my reading list too, as I build an 8 VS and Rudder to put a counterbalanced rudder on my S6. Will be interested in your interpretations.

Cheers,
Bob

PS: Same doc Brian found...

 

[DanH]

Thanks guys. I actually clicked that Google search link this AM but it took so long to load I thought it was broken

 

[stevemcgirr]

basic flutter prevention questions

I printed and am trying to digest the article you referenced. It's definately going to take a few re-reads to get through.

I am wondering how important moment of inertia is to the generation of flutter. Apparently, a concern in the Canadian RV7 case was the application of a complex paint scheme, leading to increased control surface weight. Why would evenly distributed weight, which would seemingly leave the control surface in balance, lead to a decreased critical flutter speed? Would not a lighter control surface, or one whose weight was concentrated near the axis of movement, have decreased MOI and increased flutter tendency? By way of illustration, Jack Nicklaus is said to have preferred heavier golf clubs, for "feel". To keep the "swingweight" (roughly a measure of MOI) acceptable, he supposedly added backweights to the grip end of the club

Also, I take from the Rosenbaum article you referenced that the counterbalance should extend over as great a span of the leading edge of the control surface (as in an RV aileron), and not, for torsional concerns, be concentrated at an apex (as in the RV rudders and elevators).

I am grateful for the article reference

 

[DanH]

I wanted to look at Report No 45 because it is referenced so many places.

A really interesting piece popped up in the same Google search:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070008390_2007008628.pdf

 

[N999BT]

I am wondering how important moment of inertia is to the generation of flutter. Apparently, a concern in the Canadian RV7 case was the application of a complex paint scheme, leading to increased control surface weight. Why would evenly distributed weight, which would seemingly leave the control surface in balance, lead to a decreased critical flutter speed?

I don't understand all I know about this subject, but here is my simple explanation to your specific question. The reduced critical speed is because the moment of inertia is taken with respect to the hinge line. More weight (moment of inertia) equals a lower natural frequency of vibration. This frequency is related to a critical airspeed so by increasing the mass in the surface you reduce the margin between actual speed and critical speed. I hope this helps, and happy reading on this old stuff! Those guys that investigated all this before computers were really, really smart.

 

[Bob Kuykendall]

I wanted to look at Report No 45 because it is referenced so many places.

A really interesting piece popped up in the same Google search:

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20070008390_2007008628.pdf

I dunno, that airplane in Figure 11 looks pretty sketchy...



Thanks, Bob K.