Wright Stuff B

[calgoddard]

The SciOly officials sought input on potential rules for a helicopter event last year.

I built a rudimentary copter that met the rules in about an hour. It did about 20 seconds in my living room. It had the typical arrangement of a vertical MS with a plastic prop on the top rotated by a rubber motor and a flat bladed balsa prop on the bottom with an opposite pitch rigidly connected to the motor stick.

As I recall, it would be tough to beat one minute under the draft rules, but the model I built was not very light and could have been improved a great deal.

Personally, I prefer the WS event as the indoor flying event, but the helicopter event could be fun and a nice learning experience for students. We have some great WS mentors in our area, but they know little or nothing about rubber powered helicopters.

[jander14indoor]

Well, I hope we are keeping the weights high enough, but not too high, size small enough, but not too small, and enough rubber to be as easily buildable as WS or BLG. Goal was 1 minute plus flights, we've demonstrated at least that much. And the best copters still have the elegant flying behavior of the best WS or BLG planes.

As to mentors, I hope the indoor folks don't drop out, because the same skills will be invaluable in coaching students. Wood selection, careful building, aerodynamics, rubber winding, and TEST, TEST, TEST will still be the keys to success. Skills any indoor or outdoor freeflighter has in abundance.

And don't worry, Wright Stuff and BLG will be back.

Jeff Anderson
Livonia, MI

[blue cobra]

Random Question:
I've used 1/16 sq for pretty much everything on my planes (wing and stabs). I always have a gram or two to spare, so I figured why not use 1/16 by 3/32? Added strength is always good, after all. What are your opinions/advice on this matter?

Now for something completely different, why would you angle the stab down? I know this would push your back end down, giving you downthrust with your prop, but it seems this would add drag and decrease lift. Also why do you have camber if you angle it down?

[Dark Sabre]

Some 70 new pics from nationals are in the Image Gallery. Planes are apparently not fun to take pictures of while in motion, but hopefully some of them will be useful.

[jander14indoor]

For anyone who wants to know what I look like, that's my right hand on the left edge of picture #50, my right hand again in #48 with the gage checking planes, my shirtsleeve and elbow in #45,

and then,

wait for it,

a full shot of my back (white shirt on the left) and the national event supervisors back (white shirt on the right) in #3.

Wooo, thought they were going to blow our covers there for a moment.

Oh, the plane over my head in shot #3 and closeup in shot #46 is my personal WS plane, covered in Home Depot grocery bags. 7.1 gm or so and best times well over three minutes. While the specialty indoor covering is nice, it just isn't necessary for success in Wright Stuff. As discussed earlier in this string.

You can see parts of my home made balances (also discussed on this list) being used to check planes and motors in shot #50.

And for anyone not recognizing my weird brand of humor, I'm really impressed how the photographer got NO clear, and only two fuzzy adult faces across the day's competition. But quite properly lots of shots of students and their planes.

Jeff Anderson
Livonia, MI

[carneyf1d]

Haha. Now if only i could cover my ministick or f1d in home depot bags maybe i wouldnt have to waste 35 bucks on film.

Random Question:
I've used 1/16 sq for pretty much everything on my planes (wing and stabs). I always have a gram or two to spare, so I figured why not use 1/16 by 3/32? Added strength is always good, after all. What are your opinions/advice on this matter?

Now for something completely different, why would you angle the stab down? I know this would push your back end down, giving you downthrust with your prop, but it seems this would add drag and decrease lift. Also why do you have camber if you angle it down?

You should be able to get by. If you use light density wood, around 5-6 # then you can definitely do it. Heck i build a plane two years ago with 3/32 by 3/32 balsa wood. The thing was a tank, but the balsa was really really low density and took forever to find. I would suggest buying sheets of balsa instead of single spars, and then just cutting the sheets down to size. You can check density of sheets by holding it up to a light and finding a piece that is light colored. And build so you still have around .5-1 gram left, and add balast to change CoG of your plane. If you want extra strength to you plane also check grain on the sheets you buy. There's A, B, and C grain and they each have certain strengths and weaknesses regarding flexibility and rigidness.

Believe it or not, the stab is supposed to have a negative lift. On massive commercial aircraft the center of gravity is in front of the wing, and because of torque the stab would have to have negative lift or else the whole plane would be doing a front spin. On light weight indoor aircraft, you dont need as much downward lift. And in fact the CoG is located under the wing or slightly behind the back spar, so maybe only a little upward lift may be required. This is why there is slight camber (but usually very little like 2-3% simplex) and the stab is angled downward only like 2 degrees or is even zero when you have massive (unlim chord) wings.

[jacdad]

Glad the discussion got going again.

Thanks for the pics. Loved Jeff's plane. Sort of says "It's not rocket science." doesn't it?

One thing my son played with a lot when trimming was stab incidence. It seems to have great influence on the plane, probably because it is so far from the cg. He improved some times by putting more down angle in the stab and less incidence in the wing. I think this cuts overall drag, since the wing is so much bigger.

One question. The "drooping" tail booms on so many planes, is that to get the stab out of the wash from the wing, or does it serve another purpose? Thanks.

[GitItWright]

One question. The "drooping" tail booms on so many planes, is that to get the stab out of the wash from the wing, or does it serve another purpose? Thanks.

Yup, serves two purposes. 1) as you stated, to put the stab further from the wash too make the small area more aerodynamically effective and 2) to intimidate other teams and create a trend.

BTW, Dark Sabre's offhand remark about how tough it was to see airplanes was probably the reason using tissue to mark various surfaces was introduced a few years ago. Though no specific aerodynamic advantage comes from the colored markings, it sure makes it easier for your team to ID its airplane from 50 others.

Good Luck.

[49ers]

Random Question:
I've used 1/16 sq for pretty much everything on my planes (wing and stabs). I always have a gram or two to spare, so I figured why not use 1/16 by 3/32? Added strength is always good, after all. What are your opinions/advice on this matter?

Now for something completely different, why would you angle the stab down? I know this would push your back end down, giving you downthrust with your prop, but it seems this would add drag and decrease lift. Also why do you have camber if you angle it down?

Sometimes going with the denser wood is better than getting bigger wood, My science O coach weighed all of our balsa seperately, and it helped us have a better plane(It did take forever granted)

[smartkid222]

Random Question:
I've used 1/16 sq for pretty much everything on my planes (wing and stabs). I always have a gram or two to spare, so I figured why not use 1/16 by 3/32? Added strength is always good, after all. What are your opinions/advice on this matter?

sure, if you feel like it you can make it 1/16 x 3/32. Just make sure you check the densities of all the wood you make your target weight.