ORIGINAL: Kevin Greene
Snip for brevity...
What you posted in your first two paragraphs is EXACTLY what jet guys have been saying about our corner of the hobby ever since our hands were tied by thrust to weight ratios and speed limits.
J_R,
Matt is correct about BVM but others do post a Vne....My Composite ARF Rookie has a manufacturer recommended Vne of 200 MPH. However, my Composite ARF EuroSport does not have a recommended Vne....Because the manufacturer knows that this particular plane will not go fast enough to cause a problem for itself.
Kevin
kevin- I would almost believe you were it not for the generalization "jet guys". I have seen some of the kits, and some of the airplanes, and read a fair number of articles about them. No, I don't fly jets-finances and family concerns prevent that--and there is nowhere close to Roswell to see much in the way of jets, but I have managed to see a large number of DF, as well as large scale prop aircraft.
What the builders and designers of some of those models (particularly the "self schooled" designers) know about structural design scares the pants off of me (that is a sight you don't want to see).
When you are up in the 20+ pound category of high-performance models, you need more than a rudimentary knowlege of structural design. Balsa and fiberglass are wonderful materials, if used appropriately. Unfortunately, in a lot of cases, they are not.
Composite (graphite, fiberglass, boron, etc) are best used with epoxy, not CA. You do not get the strength you need just from the material--you need the carrier, too. and CA is a really crummy glue for high-strength applications in shear.
Heck- I know a guy who thinks that painting the fiberglass onto wood with Acrylic latex gives lots of strength. The guys who vacuum bag with epoxy are doing it correctly-but I want to see more structure under that skin!
And balsa is terribly inappropriate for the strength applications in spars and d-tubes at those levels. I use spruce spars in my .40's, for crying out loud!
The control line guys have to do a pull test. This is a guarantee that the control system won't pull out, and that the plane will stay attached to the control system, barring a cut of the wires. and yes, they do 200+ MPH.
Can you think of a similar test for RC? Are you willing to suspend your airplane by the wing and put 10g's on it? (that's 200lb for a 20 lb model). You pull a lot more than that in some of the manuevers you do--especially the abrupt pull-ups
Even such a test STILL wouldn't guarantee that the control system will stay attached to the aircraft... The vagarities of radio waves, ya know.
BTW- that is what I do for a living. Making sure things won't break.
Roger