Chris Hill
Well Known Member
What is the fastest indicated/TAS you've ever had in your RV (preferably in a Vans RV)?
EAS is TAS corrected for compressibility effects which below Mach .3 are negligible.
Read about it here... http://www.vansaircraft.com/pdf/hp_limts.pdf... for flutter TAS is key. for air loads on the structure IAS captures the mass force resistance of the air similarly regardless of pressure, temperature, or altitude...
I think you'll find that aerodymanic flutter can occur to any part of the aeroplane, not just the control surfaces. To think it limits itself to just the movable surfaces is a dangerous train of thought.Now, here is an interesting thought: Since flutter is based only on control surfaces, what would happen if someone were to build a hybrid RV-X using tail and wings from "some other airplane?"
As usual, NASA has a beaut Youchoob video showing a spam-can undergoing flutter testing. Scary stuff.
A turbulence bump or a small control stick input can excite the structure to flutter. Be carefull thinking that just beacause someone flew above a Van's listed Vne does not mean it is safe for all to fly at those speeds.Chris
Yes there are RVs that have gone faster but you are treading on dangerous territory. No one really knows what one bump of turbulence would do do your aircraft at these speeds.
You can calculate flutter speed if you know the structual stiffness and all bending modes. Not an easy calculation and not very accurate. Not sure how Van's set Vne but do not believe he did a full flutter test. At the big companies they can only fly to a certain percentage of calculate flutter speed if no flutter test was done.I dont know that Vans actually tests for VNE for the airframe since they have apparently not ripped the wings off in testing flutter. Must not have found that limit yet...
Excellent video showing that the fixed structure can flutter just as easily and a movable control surface.I think you'll find that aerodymanic flutter can occur to any part of the aeroplane, not just the control surfaces. To think it limits itself to just the movable surfaces is a dangerous train of thought.
That it usually occurs on this part of the airframe is simply because they are the most movable parts. Fly fast enough and you could well find your entire wing doing the higgidy-diggidy.
As usual, NASA has a beaut Youchoob video showing a spam-can undergoing flutter testing. Scary stuff.