Biber has it spot on. From what I've read 25 deg. of sweep or more needs anhedral. My DLG wing has 30 deg. of sweep and needed 1.5 deg. of anhedral per side and thats only a 60" wing.

Vern

Originally Posted by biber

sweep does act like dihedral, whenever the swept wing does create lift. So at low speed, the dihedral effect of the sweep contributes noticably to the whole and at high speed it hardly does at all.

With sweep and winglets you have lots of effective dihedral already and in many cases less would be better.
Then you build some anhedral into it to have just the needed amount.

Here's an article on the dihedral effect due to sweep.

--Norm

Originally Posted by Vernon Hunt

Paul,


How's your thermal wing coming along?

Vern

I'm powering on with decorating at the moment but I'll start heating up my hot wire in a few weeks and move the thread across to this forum

Paul,

I can't wait to see the finished product. I got the servos in and the fuselage glassed. I hope to glue this pod on today and start the finish. I do have a set of cores for a Horten style wing I cut 3 years ago. Maybe I otta press some balsa on them and see how it flys.

Vern

Vern,

I broke out my magnifying glass and I could not see any control surfaces near the root. Does this ship fly with Elevons only?

Also, at 100" wing span, this puppy could float. Do see a need for any sort glide path control?

Kent

Kent,

I have found that flaps is luxury that a light glider like this does'nt need. Saves weight. At a good field without trees in the way I can land it predictably at my feet.... most of the time. Gotta plan ahead.

Vern

Heres what I've got as of noon today. Looks like it might be a good flyer....

Vern

As it doesn't fit in the car, you'll be walking to the field with this beauty then Vern?

Also can we request some movie of the launches? I'd love to to see how she goes up the line.

Very elegant wing you have there. Nice one.

Happy New Year!

Paul,

Yes, I will be walking...... not, I will have to keep the rear door open cause it sticks out the back about 12". I wanted to save as much weight as I could, so I glued the thing together. There are trade-offs that have to be made when one has very little money.

Thanks Shedofdread

Happy New Year!

Vern

Originally Posted by Vernon Hunt

Paul,

Yes, I will be walking...... not, I will have to keep the rear door open cause it sticks out the back about 12". I wanted to save as much weight as I could, so I glued the thing together. There are trade-offs that have to be made when one has very little money.

Thanks Shedofdread

Happy New Year!

Vern

Vids will be available

Originally Posted by Vernon Hunt

Heres what I've got as of noon today. Looks like it might be a good flyer....

Vern

She looks good Vern.

Brian

Originally Posted by nmasters

Here's an article on the dihedral effect due to sweep.

--Norm

OK, I've clearly overdone the mince pies and mulled wine but if one uses the formula on p14 to get the effective dihedral for the Co8 design described at the end of ther document, I certainly don't get the 1.5deg that's quoted.

Would someone be so kind as to run that calc themselves and see what they get. It's driving me nuts.

Many thanks (he said, off to somewhere quiet...)

Originally Posted by Shedofdread

Would someone be so kind as to run that calc themselves and see what they get. It's driving me nuts.)

I had the same experience. It's a slippery subject. What bothers me about such technical papers is that they sometimes state a formula without showing how it was derived. In structural design this would be unacceptable. A formula may be just an estimate of an observation. Not knowing where the formula came from leaves me in the dark.

With that said, it was a good article. I learned a lot. For me, I had my answer with biber's post #30. I know, I know....how much anhedral is needed.....

Kent

Vern,

You appear to have a knack for building light planes. You have a big balsa end cap at the tip that you mount the winglet to. Is this structure wrapped in FRP or does just the wood get the job done?

I do not believe that I have ever built a wing with big winglets, but I would think that I would be snapping them off on a regular basis. I fly at steep slope sites with tiny LZ's that do not always lend themselves to upright landings.

Kent