the "Bruce" is Bruce Tebo - apparently a lovely guy - and is also Aloft's test pilot and de facto Ambassador.
A reportedly highly competent flier, Bruce is one of only a very few people on the planet who have gone over 500MPH with a DS model.
For the lowly Stormbird, I honestly have no idea what the theoretical flutter point would be because it depends on the entire control train, plus the control surface construction plus a lot of x and alpha. Obviously a carbon reinforced surface with a thicker hinge would be less susceptible to the dreaded shake rattle and roll.
The Stormbird that Bruce took to 174 MPH before flutter set in was an old and apparently well used example. Since then both the construction and materials used have been improved and so I guess it would be less likely to flutter.
Hopefully in the not too distant future, Bruce will be rearmed with a more robust example and then we will probably discover what the physical limits of the model may be. The aerodynamics will "Take it" but not being an expert on models at such speeds I'm not sure how far the materials and construction will go.
I've flown with that "Bruce" and I can report he is all that you mention!
Yep, design speed limits and actual speed limits are rarely the same for the reasons you mention.
What improvements have been made in the materials? Have you changed the epoxy, changed the fiber weave, gone with structural foam? Is it a process change like the fiber lay up changed, post cure heat treatment schedule modified?
I have a few RCRCM ships that show vastly different material performances, even between the wings on the same model! Quality pays it does not cost. Both you and Wayne warned me about the quality from RCRCM!
...the control horn of the servo on the aileron broke and then the aileron began to flutter. The surface control horn was a allready glued in. The servo horn was too weak and lost its confidence. I then lost my beloved SB, I was not able to manage a save Landing (the good point of the story: the plane didn't look down somewhere into the valley to hide himself, it crashed after a nearly full circle just behind me)
I first checked the servo horn and found out that it was too much of less material to use it here, although the 2 year old SB had seen bigger storms, so it must be somehow of materials loser or bad air
The possibilities of the airframe are a way more higher. The limit was in this case set by the linkage and lead to aileron flutter. But planes can also flutter with very tight linkages because of physical properties
We are always seeking to improve our products. If we see room for improvement, we will always share this information with our suppliers. This goes for anything we sell. We try and take a very active roll with our manufacturers to offer better and better products for our customers.
With that said, we are currently working with Doc to offer a new version of the Stormbird that is a bit beyond his comfort level. I am excited about the prospects, and he seems to be also. Normally you would never see Doc talking about such speeds on his airframes. So why the Stormbird? Well, I love how it flies, and it has that massive wing joiner. I doubt you will find a 2 meter plane with a larger wing joiner. The convenience of a 2 piece wing, but the strength of a 1 piece wing. Win win.
Intended use is DS Acro where speeds tend to be below 250 mph. The plane has no issues on front side, these are DS speeds we are talking about, and the plane was never intended for, thus a few tweaks and plenty of testing. The tweaks will add weight, mostly tail weight, so not something one would want for a front side only plane. If testing goes well, this will be a special version for this special task.