Earthstar Forums

Out of the weeds....and safe from flutter.

Martin, why did you use the lighter Oratex, everywhere on the gull except the stabilator?


--ray

I figured the stab and rudder would see more turbulence and possibly rash
than the wing. I still think that was a good call - scraped the stab on
some gravel, but the wing was always in the clear. Still looks good after 3
summers outside (the red has faded a little, but uniformly). Since I used
two versions of Oratex, I was also able to use red fabric for the tail, and
"silver" for the wing (inc. ailerons), to avoid too much contrast on the
wing. The red wingtips and prop optically tie the whole thing together
nicely.

Hi Martin
No! The led is only there to balance the horizontal stabilizer so that it does not flutter. This is a standard practice that is require on Aircraft with higher VNE or, Velocity of Never Exceed. Yes it does not need as much lead if the stabilizer has less paint, paint is heavy and so I add enough led because people paint there planes, than they paint them again not realizing that they add to much weight to the stabilizer behind the hinge the stabilizer will flutter at high speed.
It could kill you! So I try to look out for you by adding extra lead to allow for extra paint.
Hopefully 20 years from now if Martin sells his plane to some one that wants to paint the tail, that hey will know to add led????
As long as the trailing edge doesn't fall the stab is balanced well enough to be safe!
Happy Flying
Mark
Sent from my iPhone

but, the tail already looked so pleasing unpainted or fabric covered. any precedent for using silk? durable, strong as steel and everything, it simply must be lighter. don't mind if it fades or whatever.

what's the specific weight of oratex? and the weight of one paintjob itself (just to remind me)? how many pounds can we reduce in the tail for an unpainted gull, that'll never be painted, only polished? am so looking forward to mr. greenwood's silvergull, is that really all aluminum?

silkegull.. sweet mcdreams are made of this,
r2c2

https://www.ellesilk.com/blog/durability-of-silk/

but, the tail already looked so pleasing unpainted or fabric covered. any precedent for using silk? durable, strong as steel and everything, it simply must be lighter. don't mind if it fades or whatever.

what's the specific weight of oratex? and the weight of one paintjob itself (just to remind me)? how many pounds can we reduce in the tail for an unpainted gull, that'll never be painted, only polished? am so looking forward to mr. greenwood's silvergull, is that really all aluminum?

silkegull.. sweet mcdreams are made of this,
r2c2

https://www.ellesilk.com/blog/durability-of-silk/

Thanks for setting me straight, Mark! I remember now that you were
concerned about flutter when you came up here to test-fly the Quark.
Fortunately, you did not run into any signs of incipient flutter, even at
higher speeds. And my stab still has enough ballast to drop its nose if
there were no friction from the controls. But your point is important:
Flutter is dangerous! You have shown your design is flutter-proof. And
static balance is much less significant once you get into aerodynamic
loads. In my case, even going to Oratex changed the equation (less mass),
but reducing the ballast in response could have backfired. I am glad we got
some weight off the tail, since we expected to be tail-heavy, but the
decrease in induced drag may not be worth it. And your point about someone
in the future recovering with something heavier is valid.

Takeaway: Even seemingly innocent "improvements" can have unintended
serious consequences - check with the designer! (One of the perks of being
an Earthstar customer!)

I suspect that if my stabilator noses down when parked and jiggled, not a lot, but definitely no nose up so I guess I’m good. Just got the keys and a checkout a a Cessna 150 that I get to partner into with no cost, just maintain and exercise it. Also got my Basic Med. Real easy if you’re a AOPA member. It walks you through a self assement and a short aeronautical quiz which is forwarded to the FAA, the you get to the pdf download links to the the FAA forms to see your family Dr. It’s called a wellness exam, and it cost me $15 with my co-pay. Saved me about $135, and it’s good for 48 months. Yippee. Just know that the Cessna 150 feels like a slug compared the A Gull. That’s why I recommend Cessna time as a good transition plane for a new Gull pilot.