R

ron sterba

Well Known Member
QbRV9a. I just fitted my flaps on. My wing tip, aileron and flap trailing edge all line up perfectly BUT I noticed that the flaps at the trailing edge next to the fuselage are down about 3/8" to 1/2" below the fuselage.I noticed the flange on the last inboard flap rib overlaps the bottom fuselage by 2". With keeping all those trailing edge surfaces lined up, can I bend that inboard flange in a small arc to meet the fuselage? I am NOT finding in my VANS (A HOW-TO plan book) to deal with this. If I use a 2 foot straight edge off either the top or bottom of the wing skin it appears the flap is in the correct position when its in that 1/2" down position. I used that gauge for centering the ailerons ( I think it is the W930 gauge) to what I thought was the perfectly center position. Both ailerons are at the same elevation and have the same difference in distance down when the 1/2" flap distance is raised to ZERO. Just a note here of observation,when the flaps are in the TOTALLY up position the trailing wing skin rubs on the flap skin. Looking for answers on close tolerances. Thats the way I build things. Ron in Oregon
 
Ailerons?

Did you make the tool to align the aileron using the tooling holes in the outboard wing rib?? I think the tool you reference is just for holding the bellcrank in the neutral position. I just hung my wings for the final time, the flaps are tight against the fuselage. I have heard others have had to bend the skin of the flap like you suggested to make it close the gap to the fuse, but mine didn't come out that way. By the way, I had to cut both wingtips to make them align with the aileron when I used the tool to align the ailerons using the tooling holes.
 
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gotta gap,.... and yep, they rub

I looked at several different planes and found several different gaps between flap and fuse.

On the wings... you will see various options discussed on this forum, on where to place "rub tape", either on the flap or on the wing skin.
 
flap skin flush to fuse

Using the end rib tooling holes for aligning the ailerons, per plans, mine came out just like Don's. If the flaps are 1/2" off... then I can't help but think something is wrong. My plane had no heavy wing on first flight.
 
Assuming you properly aligned the aileron, the most likely explanation is that your aileron or, much more likely, your flap has a bit of twist in it. The trailing edge of that extra long RV-9/9A flap can be perfectly straight yet still have twist (or warp). I've noticed this quite often. In my case, the flaps fit at the fuse nicely but I apparently built about 1/4" of twist into mine where they meet the ailerons.
 
Ron,

My QB wings and fuselage lined up just like yours. I followed all the allignment procedures and used all the jigs. I had experienced help when I mounted the wings and they just turned out like you descibe.

The plane has been flying for over 250 hours, flys hands-off (when vertical trimmed) at all speeds. If I look at the elevator position when in cruise flight (about 180 mph TAS), it appears alligned with the HS. Top speed is 'as advertised' by Van.

Only issue I have is that I can easily red-line the recommended Sensenich 79" prop at 7800 DA. According to what I have read, at 7800 DA with a standard O320 / 160 hp engine, I should not be able to red-line (2600 rpm) the prop. So, I think the plane is well rigged and slick and I don't think the space between the trailing flap edge and fuselage is an issue on my plane.

I would like some day to try an 80" or 81" prop to see if that increases my top speed which is now about 193 mph TAS without red-lining the prop.
 
Ron,

My flaps are also up tight against the bottom of the fuselage. Although one side is tighter than the other side. I hear that is typical. Perhaps you should double check the wing incidence to make sure you drilled that critical hole for the aft spar connection in the correct spot. That could easily explain the difference but let's hope that's not the case.

When I was at the factory the other day I noticed that Van's trimmed the end of the flap skin off just aft of the connecting rod. So the factory RV-9A does not have an overlap on the back half of the flap and there is actually a gap. It got me wondering if I did it right by leaving my skin with full overlap. I haven't had a chance to look at the plans since. You'd think it would be best not to have a gap and I'm not sure why Van's trimmed theirs.
 
My QB wings, ailerons, and flaps lined up nicely, allowing the inboard flap to nestle to the fuse within 1/8" on both sides. I think much of that was the excessive time I spent adjusting, checking, and readjusting the aileron rigging using the W-930 tool and the wing end jig bolted on the tooling holes. I still ended up splitting and regluing the wingtips, though... they were off by 3/8" or more.

I've seen another 9A on which the builder fab'ed a small piece with a joggle that he riveted to the inboard flap end .. .to match the fuse bottom contour perfectly.
 
Here's a photo of the factory RV-9A flap end. You'll notice how the bottom skin is trimmed off past the rod bearing. Has anyone else done this or did I miss that detail in the instructions?

RV-9AFlap.jpeg
 
Hello Don, Yes I used the tooling holes on the outboard rib just as they stated in the plans.Tried to get a exact fit to within 1/32" of a inch.

Ron
 
Hi Joe, Thanks for your feed back. I guess I thought that the QBuild flaps and ailerons are perfect and appeared level on the concrete floor. When we set the incidence we check rechecked double checked up to four times prior to drilling the aft holes for the aft wing bolt attachment. The F-999 wing root fairing appears to be straight across on the bottom at the aft end of the strip. So I feel better now that you builders have given me a feeling of you are not alone, but I'll be up at Vans factory in a day or so and I'll ask them.Appreciate the feed back and looking forward to a first flight. Dynon 10" and Catto Prop.

Ron in Oregon
 
Hi Terry, I guess I haven't heard the term splitting the tip. How is that done and why? I know when I slid the wing tip on the joggle in the fiberglass tip that lines up with the wing skin, it was off maybe a 1/16" of a inch. I say this because when I lined up the aileron trailing edge with the trailing edge of the fiberglass wing tip( To keep a straight edge along both edges) I figured it (edge) would be consistent with the flap trailing edge all the way to the fuselage. All three surfaces are, and both flap gaps at the fuselage are within 1/32". Now I might be splitting hairs here but we are building machines that are 25% of the speed of sound. Mark that was interesting about the Factory 9A in that the top of the flap was trimmed. This can only make me think that a designer of a aircraft might say that there are different builds in fuselages and to make the aircraft to comply with the closest aero dynamics. I say this because in a perfect B-1 bomber build you might just bolt your wings on in the holes provided, for and aft. So, in this case, you set your cabin level ( mine set with a digital level within 1-2 tenths of a degree). So setting the incidence separate and acknowledge the difference and to fly the machine makes us pro-builders. I love this THINK TANK that Doug has provided. You guys are great.

Ron in Oregon
Chptr 292 Vice Pres
 
Hello Wallace. The rub tape sounds good, one builder said put it on the flap and one said to put it up under the trailing edge of the wing skin where it would ( BE Effective) still rub but be out of sight. I don't know about you but I have been to so many RV aircraft gatherings and fly-ins you would think a person would pick up on these things we discuss on the forums page such as gaps in the wings at the fuselage.

Ron in Oregon.
 
Thanks Joe . Much appreciated. If there was one thing I learned here was to drill the hole in the fuselage for the Flap Push rod. Builders who haven't cut the hole yet, heres the simple way of doing it. Observe the hole on the inboard side of the flap for the PUSHROD attach point. Attach the flap to the wing. Go under the fuselage and look at the pushrod attack hole and mark a line on the fuselage across from that hole. Place a quarter over the line that you just drew (centered) and keeping the quarter even with the fuselage edge. Draw a circle around that quarter. remove the quarter saving it in a jar for your EFIS display. Use a uni-bit and start enlarging the hole to at least 3/4". This will put you in the ballpark. the center spot of starting this hole. I used a dremel 1/2" sanding drum to enlarge the hole as needed.

Ron in Oregon
 
Rupester said:
... I think much of that was the excessive time I spent adjusting, checking, and readjusting the aileron rigging using the W-930 tool and the wing end jig bolted on the tooling holes. I still ended up splitting and regluing the wingtips, though... they were off by 3/8" or more. ...
Click to expand...
Our flaps were about a 1/2 inch low when aligned with the aileron before we spent many hours and several iterations through the aileron alignment process. After which everything lined up except the tips that were split to match everything else...
 
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Hi Dave, I got up to look at several RV9s and I'am not going to nick pick until later. Seems I looked into page 15-2 about the travel of the flaps down, well after checking my FULL UP position with edges misaligned by 3/8" of a inch and full down at 37 degrees this must be the perfect world because the minimum travel down is 32 degrees which I have with all edges in line (but with a 3/8" gap at flap and fuselage) tells me to read into the variable (32-37 min/max) and I think we all have in this posting of my,yours and the rest of the builders that we can achieve stardom! However your point is well taken and noted and will use it later and also share it with other builders. Thanks Dave and maybe I'll see you at Vans home coming someday which is at our EAA 292 hangar.

Ron in Oregon
292 chptr Vice Pres
 
flush or ????

mcattell said:
Here's a photo of the factory RV-9A flap end. You'll notice how the bottom skin is trimmed off past the rod bearing. Has anyone else done this or did I miss that detail in the instructions?
Click to expand...

Perhaps they got tired of people asking why the flaps didn't fit tight to the fuse? :)
 
Hey Perry. I was looking at that flap picture that was submitted and I got to thinking its like a gear door,when the flaps are full up it covers the the push-rod hole. Neat idea! The rest you trim off.

Ron in Oregon
 
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