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TVCasualty
08-08-2008, 05:16 PM
My experience with WWI era flying models is very limited.
I had an SE5A which flew wonderfully, with one exception…
Any wind what so ever made anything, including takes off almost impossible.

Is that the standard for these light weight high lift birds, or was my model just flawed? What’s a good bird that can handle some wind?

I'd like a really big bi-plane, but zero wind days are few and far between where I live.

WWI Ace
08-09-2008, 09:34 PM
Bipes and tripes of any size are affected by wind. The bigger they are the more wind they'll handle. Sometimes ya just gotta deal with a little bouncing in order to fly on a windy day. Steve

BradT
08-10-2008, 07:56 AM
TV, the flyabilty of a bipe in wind depends on a lot of factors: wing loading/size, power, and direction of wind to runway. My lightest, the E-Flite Jenny, at 4 oz./sq.ft, will only tolerate winds up to about 5km/3mph, and then only straight down the runway. My next heaviest, the H.L. SE5a, same span as the Jenny, but at 8 oz/sqft, will handle at least twice as much wind, and up to about 15 deg. off the runway centerline. My 51" Tiger Moth, 13 oz/sqft, seems to take winds up to 25km/15 mph, with no trouble at all, even at angles as high as 45deg. to the runway. The rudder is very effective on the Tiggy, and sideslipping in to touchdown is actually a lot of fun on breezy days. My largest "doppledekker", the scratch built 75" D VII in my avatar, has the same wing loading as the Tiggy, and will fly in wind speeds as high, but doesn't tolerate cross winds at all; very touchy to take off and land if the wind is more than a few deg. off centre. All of these, except the very light Jenny, handle steady wind well, once they're up. The jenny is slow enough that a moderate breeze could have her flying backwards!

Build your bigger bipe, and try it at your field, I'll bet that you'll be pleasantly surprised at how well it'll do, with a little practice on your part. At this time, my 51" Tiger is my favorite flyer, after spending some time getting her trimmed out right. She's also small enough to transport in 1 piece, unlike the big D VII, but still big enough to have lots of "presence" in flight.

Brad.

TVCasualty
08-10-2008, 07:17 PM
I guess what I noticed was perfect stability in calm air, then as wind picked up vertical stability went right out the window. Turning into the wind if the CG would shift to the rear, as any increased air flow over the wings tended to throw everything off. Too much lift. Away from the wind, CG seemed to shift way forward, unresponsive controls, a terror to try and fly in circles.

Does that sound familiar?

BradT
08-11-2008, 07:32 AM
TV, that sounds like a problem with your particular model, not the way most biplanes fly in wind. There may be a cg problem with your plane; which SE5a model is it? Wingspan, weight, cg point? The other possibility is that the wing or tail incidence could be off, causing the strange upwind/downwind pitch changes that you describe.

I flew both the Tiger Moth and the Hobby Lobby 38" SE5a today, in wind speeds of about 15 mph when the Tiggy was up, and 5 to 7 mph when the SE5a flew. I did have a hard landing with the SE, after maybe 100 flights on the model, I bent the gear strut on one side. The wind was strong enough that the SE, on its foam cradle, was blown off the tailgate of my truck, damaging a lower wing tip and aileron tip. I fixed it at the field, and flew when the wind moderated a little from that level.

Kursal
08-12-2008, 01:08 AM
I guess what I noticed was perfect stability in calm air, then as wind picked up vertical stability went right out the window. Turning into the wind if the CG would shift to the rear, as any increased air flow over the wings tended to throw everything off. Too much lift. Away from the wind, CG seemed to shift way forward, unresponsive controls, a terror to try and fly in circles.

Does that sound familiar?

I had something very similar with my Sopwith on it's maiden. Turned out the wings were misaligned. So, back to the workshop it went and I had to wait until the following week to try again.