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Old Dec 07, 2012, 04:40 PM
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Originally Posted by Sopwith Mike View Post
I don't know. The ones I've seen flying at Old Warden seemed to be working perfectly, and they are supported on just the one overhung bearing aren't they? If there was imbalance, as you say, they'd just fall apart

Yeah, that makes a lot of sense. They simply "must be right" or else they wouldn't work so well.

I'd like to fly behind one.
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Old Dec 07, 2012, 08:02 PM
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RMCCOR7737's Avatar
United States, VA, Stafford
Joined Jun 2009
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Just a little update. I worked on the LG when I got home from work. Got it all laid out and ready for soldering. I temporarily have it attached by sheet metal screws. I will use blind nuts to attach it later. Also put a little stain on to see how it looked shade wise....

Had to double check that upper wing incidence again, somehow my rear strut slid down giving me way too much incidence. Da#! it...something else to fix...
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Old Dec 08, 2012, 06:52 PM
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Tinkered a little more with the fuse today. Just added a little details. I still have to do the machine guns. I'm just gonna do from the hump forward as I am beginning to put on weight. Soldered the LG this mornin'. Installed the new battery tray. Kinda got a feel for CG, I think I'm gonna be very close.

With everything but rigging and covering I'm at 25.6 oz.

I like lots of pictures....
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Old Dec 09, 2012, 04:36 PM
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Whew, finally moved on from the fuse and brought myself to finally work on the other end. Got the rudder built up and sanded out. It looks small to me but I am guessing with the dihedral in the lower wings it should be OK. Ready to start setting up for the outer struts then I will jump back and get the aileron cables in the lower wings. Weighed everything again, I forgot the ESC yesterday, and came to 28.8 Avoirdupois Ounces. Not too awful I recon....

Question time again for the bipe enthusiasts out there....I was gonna add a 1/2 degree to the stabilizer to reduce having to trim in down elevator, will it subtract from the incidences in the front wings?
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Old Dec 09, 2012, 04:57 PM
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Nelson, B.C.
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Looking very nice Steve. I am building a small DVII right now and should have scaled up some. A 36" span is too small for my old hands. Want to build several WW I jobs this winter. Will be watching.

Kim
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Old Dec 09, 2012, 05:37 PM
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Originally Posted by chumbly View Post
Looking very nice Steve. I am building a small DVII right now and should have scaled up some. A 36" span is too small for my old hands. Want to build several WW I jobs this winter. Will be watching.

Kim
Thanks Chumbly....by the way you can call me Robert...
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Old Dec 09, 2012, 09:03 PM
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Beautiful work!

Conrad
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Old Dec 09, 2012, 10:00 PM
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Just don't call him "Shirley."

In a sense, the short answer is "Yes." The tail force works to balance the "wing pitching moment". As the horizontal stabilizer is usually designed to produce negative lift, then the wing must fly at a slightly greater AOA to provide additional lift, so that the net aircraft lift balances weight.

I'm visualizing your aircraft in level, unaccelerated flight, with the long axis of the fuselage parallel to the direction of flight; for minimum drag. If the CG is behind the combined Mean Aerodynamic Chord you will need a down force generated by the Horizontal Stab.

But, surely, any change to speed, throttle, or attitude will change the direction and magnitude of the force needed.

If you hinged the stab at the elevator hinge and use a set-screw at the leading edge, you make a incidence changeable on the ground.

The real thing does it with stacked washers... http://www.biplaneforum.com/f13/stab...nce-angle-990/

Quote:
...this is the way it has always been done. Its' one of those places where the normal rules about washers doesn't apply.

The method for adjusting is usually to fly the airplane in the most common load configuration and trim for level flight. Have someone in a chase plane observe and photograph the tail. You then know to add or remove shims until the elevator and trim tab are in trail.

It would be interesting to poll flying airplane owners to find out what angle worked best on particular airplane/ engine/ pilot weight combinations.

With the Acro II, the tail incidence range seems to be from zero to 1.5 deg leading edge up. The heavy engine and prop combinations seem to favor close to zero, and the heavy pilots, like myself at 240 get close to 1.5 deg LE up.

I think the Skybolt has a longer arm distance for pitch force (This would mean the distance from the effective pitch center of the wing cell to the hinge line of the elevator) than the Acro II so less change would produce more affect.

To figure the amount of rise at a given point, such as at the "H" tube (front spar carry through) multiply the sine of the desired angle by the distance between the centerline of the stabilizer spars. In the case of the Acro II, to raise the incidence 1.5 deg multiply.026 (sine of 1.5 deg) times 19" (the spar centers) which is .497. Call that 1/2". (From the Acro Sport Newsletter-Rigging)

You could use 1/4" spacers and each spacer would be 3/4 of a degree.

It is beneficial to know this angle and record it in the airframe log book for future reference. Like where you are now. (John)

It would be in the builders best interest to set the incidence at the carry through spars before building the stabilizers, then build the stabilizers to fit the carry through's. This will prevent binding of the bolts in the "H" tube. Because the stabilizer swings in an arc when adjusted, you have a very small range of adjustment that doesn't bind the bolts.
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Old Dec 10, 2012, 03:31 AM
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Originally Posted by davidterrell80 View Post
Just don't call him "Shirley."

In a sense, the short answer is "Yes."
But, surely, any change to speed, throttle, or attitude will change the direction and magnitude of the force needed.

If you hinged the stab at the elevator hinge and use a set-screw at the leading edge, you make a incidence changeable on the ground.
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Thanks David.
I was considering adjustable stab. I recall reading somewhere that most of the old biplanes used throttle to gain or loose altitude and the stab was basically used to change the attitude of the plane.
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Old Dec 10, 2012, 03:53 AM
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Beautiful workmanship. starting to look the part now.
Alfred
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Old Dec 11, 2012, 08:19 PM
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Beautiful workmanship. starting to look the part now.
Alfred
Thanks Alfred. Not much progress to report today. Spent most of the day hanging new doors in my house. Did get a chance to start playing around with the inter-plane strut mounting though...this is where every thing starts to slooooww down...
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Old Dec 12, 2012, 07:59 PM
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Kinda put it all together for set up. I need to place some webbing I believe between the front two spars on the wings as I am getting some waves in the leading edge when assembled. The inter-plane struts do add some rigidity to the structure as far as load bearing goes. The bolts on the struts will be cut flush when completed. I am not sure if I am gonna turn them around so the bolts come from the other side or not yet. A lot more work to be done on the wings yet before covering begins...

FYI, most of the pics I post are so that I may get an unbiased perspective of the airplane.
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Old Dec 13, 2012, 09:30 PM
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After posting last night my wife came over by me and leaned over where I was storing my wing sets to check the phone messages when all of a sudden I here this bone chilling crunching of balsa wood..... She immediately began to ask me "did I break something?" I didn't even look as I didn't want to know. After she walked away I surveyed the carnage. No irreparable damage that could not be fixed. Now that I am a single man I may have more time to build....



P.S. - Just kidding, she broke the wing, but I am still married...
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Old Dec 13, 2012, 11:11 PM
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United States, VA, Herndon
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Many Native American peoples believe a perfect pattern is unlucky and woven blankets often contain an intentional flaw. Now that the perfection of your build is (dare I say?) violated, there is nothing to stop you from having a truly magnificent aircraft.

For me, the cat ate about a quarter of my first vertical stabilizer.
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Old Dec 14, 2012, 07:25 PM
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Originally Posted by davidterrell80 View Post
Many Native American peoples believe a perfect pattern is unlucky and woven blankets often contain an intentional flaw. Now that the perfection of your build is (dare I say?) violated, there is nothing to stop you from having a truly magnificent aircraft.

For me, the cat ate about a quarter of my first vertical stabilizer.
Yeah, I guess you are right. Something always has to christen the plane way before it ever leaves the table I suppose. I have In-laws coming over tomorrow, so knowing my wife inherited her gracefulness from her parents, I have tried to place the Camel in an obscure location in hopes it will not get further damaged.
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