steve-kerry

It seems every time I take a big floaty soarer to the flying field, the wind is blowing harder than I expected. The obvious answer is to add ballast, but that often defeats the point of having a floater! Obviously I need to take a second plane with me, something specifically for soaring in windy weather.

What do people already fly on days like this? I suspect ailerons would be a good move, leaving the polyhedral designs for lighter days. I don't want to sacrifice too much performance, it will still need to thermal well and will obviously need good penetration to get upwind when necessary. Full span flaperons? What airfoil?

Suggestions are welcome...

probligo

My local LHS (yeah they need the advert - Airsail) has a small and quite exclusive "debating society" that gets together on an informal basis from time to time (ie during my lunch break) and we debate ideas such as these at length.

Among the ideas that have "sprung to mind' (Auckland having its share of "breezes" as well) have been:

There ya go - a few of the top secret ideas from the local skunk works

steve-kerry

These two have been tried already, I remember reading about a machine called 'Bionic Buzzard' in RCM&E a few years ago *cough quite a few years ago cough*

It was a tailless 'plank' slope soarer with differential swing wings, they could be moved back and forth in unison to change the CG or differentially for turning. Conclusions were that differential movement was a waste of time and a conventional rudder would have been just as good, but the variable sweep was brilliant. It used a couple of high-powered servos to control the wings and they said it had a wonderful speed range, it would tear all over the slope and then slow right down for gentle landings. Unfortunately one of the wings folded at the pivot so flight testing was cut short, but it proved the concept was a good one. I still have the article somewhere, I'll dig it out if anyone is interested.

I believe some of the 100" Klingberg Wings had variable CG by sliding the battery pack back and forth on rails, did anyone build one of these?

probligo

steve-kerry

Interesting,....thanks for the post!

FLYBOY

My Feedback: (11)

My flat wing has flaps, ailerons, elev, rudder and crow. It has an SD-7032 airfoil. Started with the epler 214. Has a 135 inch wing and thermals with the bent wings. Flys great in the wind too. It is like the old windsong, but flies better. There are a lot of good ones. I also have a spirit elite, but it won't thermal as well.

steve-kerry

Today is another classic example of the weather I am talking about. Friday evening is glider time at our local club, there's sunshine and blue skies, some clouds but nothing to worry about - and at least 20mph winds. My old 2M plane doesn't have ballast provision, so it's grounded yet again.

Jimbonk

I think what you really want is an "Old" F3B Plane. By old I mean an 8 or 10 year old design. It won't be really competitive any more , but that doesn't mean it that it will fly badly, in fact it's only real "fault" will probably be that it won't fly Fast Enough. But it will handle 20mph with no problem, and perhaps the best part is that they can be purchased used for a fraction of what the cost originally. Don't make the mistake of assuming that they are hard to fly, with a forward CG thay can be trimmed to be pretty a gentle plane. As far as the Tx requirements you could easily "Y" cord the two Ail servos together and put them in the wings so that when one goes up the other goes down, and build differential into the linkage. As far as flap-elevator mixing you could either buy an electronic mixer or simply use a "mind-mixer", which is what we all did before the advent of "computer radios".

Jim B

steve-kerry

Hmm, not a bad idea! Thanks Jim, I'll look around and see what I can find. But I'll probably end up building my own anyway, I'm an incurable balsa-basher

Tall Paul

Don't ballast .... get a racer!
Unballasted.
wing loading 12.9 oz/ft^2.
Note the wind reading!

steve-kerry

I have an old Ridge Racer (from Sailplanes International) in the workshop, I just hadn't thought of it as having much thermal duration...

Tall Paul

I tried a ZAGI™ in that wind. Zero penetration! A TD airplane... wouldn't even need to attach the battery to the winch motor.
Just hook up the plane and hope the wings stay on during the climb!
Then go waaaaaaaaay downwind to find it!

Smythe

Haha, that reminds me of when me and my mate tried hand towing my Zagi on the top of a hill in a 20kt wind...

It went up once. Then, the string was swiftly taken from my friend's hand by the wind, and the Zagi started hurtling downwind, and then eventually span into some bushes.

We tried hand towing again, but it just veered off to the side and dived into the ground with an almighty THWACK.

I think that's when I considered repairing the nose!

eissman

Just build a high aspect ratio 2 meter at about 40 oz. It can be poly or flat. something like a heavy prodigy would work well. I have an old californian thet flies at 54 oz and thermals great.