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  #21  
Old 07-05-2010, 07:12 PM
Tony Spicer Tony Spicer is offline
 
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Location: Wilmington, NC
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Quote:
Originally Posted by REHughes View Post

What is the slowest speed that you can achieve trim (zero stick force) in clean and full flap configurations power-off in your aircraft?
If I gave you a number, it would be a guess, and most likely not a very accurate one. I never use anything but full flaps in the pattern. When the flaps come down, the trim comes full back. That's usually at 80-90 knots. With full up trim a slight amount of back-pressure is required all the way to the flare. Hardly noticeable when you get used to it. Flaps up between 90-180 knots the trim lever never moves more than 1/4" in either direction. At the higher speeds, you don't move it enough to feel it. Touch it and apply just a little pressure is all it takes. Until you get used to it, it's a bit touchy. Don't think I would like electric trim.

Tony
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  #22  
Old 07-05-2010, 09:14 PM
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fredbauerjr fredbauerjr is offline
 
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Location: 36WI, Holmen, WI
Posts: 103
Default RV3B trim

Tony,
We have approximately the very same trim issue as you describe.
#1 you need to trim full nose up, (landing configuration) #2 at cruise small trim movement gets, (quick reaction)
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turbine Mini500 helicopter, built, flown, destroyed thankfully
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  #23  
Old 07-05-2010, 09:22 PM
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fredbauerjr fredbauerjr is offline
 
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Location: 36WI, Holmen, WI
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Default Iron,

We had the same issue (horizontal tail spar forward of the fin front spar)
We also saw a picture of an RV10 and made a spacer to fill between the fin spar and the horizontal tail spar just like you did. Works great! You have to screw around with the fin/tail fiberglass fairing anyway, so no big deal, "except thinking about it"
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Rotorway Exec 162F helicopter s/n 6985, built, flying
Vans RV4, s/n 2578, purchased, flying
Vans RV3B, s/n 11366, built, flown, sold
turbine Mini500 helicopter, built, flown, destroyed thankfully
Swearingen SX300 co-builder, flown, sold
Vans RV4, s/n 37 built, flown, sold
Thorp T18, built, flown, sold
WAR 1/2 scale Corsair replica, built, flown, sold
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  #24  
Old 07-06-2010, 06:06 AM
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rph142 rph142 is offline
 
Join Date: Feb 2007
Location: Walnut Creek CA
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Quote:
Yes, we shimmed the leading edge to drawing specs. These call for a 1/4" spacer on the rear deck and under the rear spar (putting the rear spar up 1/4"). You then do the "spacer on top of the HS" thing to make your level parallel to the cord line, and set it to "zero". It took about 3/8" of shims to do this for us - and this is dependent upon where, exactly you attach the horizontal angle to the forward spar of the HS. (If you don't have the spacer under the rear spar, then you will be limited to ONLY adding positive incidence if you need to make a change...)
Here's what I did. I used a larger angle for the front spar (1x1?). Then instead of shimming up the front spar I dropped the rear spar a fraction under the 1/4" and raised the front spar relative to the angle; being sure to maintain bolting edge distance. The result is a HS with the same incidence only slightly lower relative to the longeron. Its true when they say no two 3's are built the same.
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The minimum number of planes one should own is one. The correct number is n+1, where n is the number of planes currently owned. This equation may also be re-written as s-1, where s is the number of planes owned that would result in separation from your partner.

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  #25  
Old 07-06-2010, 08:24 AM
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rph142 rph142 is offline
 
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Now Im curious. For those of you that have flying 3's, what is your HS incidence? Did you set it per plans (0.0) or did you raise the leading edge up a bit? Mine is set at 0.0 and I really hope I dont have to raise it up.
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Rob Holmes
www.myrv3.com
N59LG
The minimum number of planes one should own is one. The correct number is n+1, where n is the number of planes currently owned. This equation may also be re-written as s-1, where s is the number of planes owned that would result in separation from your partner.

- Veluminati
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  #26  
Old 07-06-2010, 08:52 AM
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Ironflight Ironflight is offline
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That's a good question Rob, but we also need to know which model of -3 (straight, A, B), and which engine/prop as well, since CG is going to be a big player.
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RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
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  #27  
Old 07-06-2010, 09:44 AM
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REHughes REHughes is offline
 
Join Date: May 2005
Location: Polson MT (8S1)
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Default Stab Mounting

Quote:
Originally Posted by Ironflight View Post
That's a good question Rob, but we also need to know which model of -3 (straight, A, B), and which engine/prop as well, since CG is going to be a big player.
I took a closer look at your stabilizer mounting picture and now realize where some of the confusion concerning shims is coming from. You mounted the stab attachment angle higher on the fwd stab spar face than shown on the drawings. The drawings show the lower surface of the mounting angle to be slightly below the lower edge of the spar (approx 1/8" below the spar bottom edge along the center doubler.)

Your fwd 'shim' looks like it results in placing the stab in about the same position as it you had mounted it "flat" with the attachment angle mounted lower on the spar face as shown on the plans. The lower edge of the spar doubler is not visible in your picture, but I would guess that it is abour 1/8" above the fuselage deck plate. Your 0-degree incidence is the same as what most of us think of as 'unshimmed' when compared to other aircraft.

Your choice of angle placement is beneficial from the standpoint of edge distance for the bolt holes in the spar, and I think I will use your method when I get to the point of attaching my stab.
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  #28  
Old 07-06-2010, 11:12 AM
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Ironflight Ironflight is offline
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Quote:
Originally Posted by REHughes View Post
Your choice of angle placement is beneficial from the standpoint of edge distance for the bolt holes in the spar, and I think I will use your method when I get to the point of attaching my stab.
Bingo - I wanted to make sure I had plenty of edge distance on the (thinner) spar material), so mounted the angle a bit higher - that meant the shims needed to be a bit thicker. Every time I pull or push the stick in this airplane, I want to have confidence that the tail is firmly attached....

Paul
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Paul F. Dye
Editor at Large - KITPLANES Magazine
RV-8 - N188PD - "Valkyrie"
RV-6 (By Marriage) - N164MS - "Mikey"
RV-3B - N13PL - "Tsamsiyu"
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Dayton Valley Airpark (A34)
http://Ironflight.com
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  #29  
Old 07-06-2010, 11:31 AM
C-GRVT C-GRVT is offline
 
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Posts: 305
Default one other (different) thing....

Paul,
a possible heads up - you didn't build the tail feathers - I notice on the picture showing the vertical stabilizer rear spar and skin that there is no overhang of the skin beyond the rear spar flange. On other RV's there is a 3/4" skin overhang that partially covers the gap between the stabilizer and the rudder. I don't know whether the RV-3 is different, and it may just be cosmetic in any event, but you might get a surprise when you are ready to mount the rudder.
Bill Brooks
Ottawa, Canada
RV-6A finishing kit I
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  #30  
Old 07-06-2010, 12:00 PM
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Andy Hill Andy Hill is offline
 
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Bill... good point.

RV-3 DWG 7 shows the details. The actual drawing of the rudder shows no overlap, but some diagrams top of LHS do. The skin extends past the spar 1/8" at the bottom of the rudder skin and 1/4" at the top... and glad it does becuase that's what our rudder has

Not sure it has much of a significance if it was missing? Doubt it'll cost more than about 10K on the top speed Paul

Andy
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