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  #41  
Old 03-06-2017, 10:00 PM
rightrudder rightrudder is offline
 
Join Date: Mar 2014
Location: Laguna Hills, CA
Posts: 1,509
Default

Looking great, John! Can't wait to see the wings in that extra-fancy wing stand.
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Doug
RV-9A "slider"
First annual completed...clean bill of health!
Tail number N427DK
Donation made for 2017
You haven't seen a tree until you've seen its shadow from the sky -- Amelia Earhart
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  #42  
Old 03-18-2017, 11:34 PM
PilotjohnS PilotjohnS is offline
 
Join Date: Jan 2016
Location: Los Angeles
Posts: 235
Default Wings-ribs


These are my wing ribs all deburred.

The two yellow spools are the sandpaper I used for deburring the holes and flange edges. I also used just a loose sheet of 220 grit pinched between my fingers for the long straight flanges. The abrasive spools were a 1/16" rope and a 1/4" flat ribbon. This worked really well. I probably used 25% of a 25 foot roll. Many of the rib flanges were fairly well deburred already, so it didn't take much more for me to be satisfied. The lightening holes needed the most effort.

I also built the rib flange forming thing-a-ma-gig sitting on the table. It forms the flanges to the perfect 90 degrees to the rib web. It works very well. However, when I tried it out, I grabbed a nose rib and looked at the flange. It measured almost perfect without me having to touch it. Then I looked at the center rib, seems perfect too. Did I spend half a day and $20 on this thing for nothing? I will finish up checking the flange angles tonight. But I will probably be too embarrassed to tell anyone how useful, or useless, this tool was. It is well worth the effort to construct for the flanges on the tail ribs, wish I had it then. But I hope I never have to rebuild the tail feathers. I am very grateful Vans aligned the flanges on these ribs; saved a ton of work.

Also in the picture are the mods I plan to make to the ribs. I talked to Van's Aircraft support on Friday and they said what I had planned seemed reasonable. If you wish to follow my example, please check with Van's yourself. So here is my plan: for the nose rib, I will enlarge the internal fuel vent hole from 1/4" to 1/2". (This is not the hole the vent tube goes thru, but the one that will be at the high point when filling the tanks.) The stock hole seems really small to me, and others have complained the tanks are slow to fill. I don't plan on doing aerobatics, nor uncoordinated flight (who does?), so I am not worried if these enlarged holes cause the fuel to slosh around a little more. For the main rib, I plan to follow the supplemental instructions on the Van's Aircraft site and add a hole in the main web to the right of the first lightening hole in the picture. This will be 3/4" per the supplemental instructions. Also the RV9 plans say it is permissible to enlarge the forward tooling hole to 1/2". But the same Van's supplement says the RV7 and 8 can enlarge this to 5/8". I will follow the 9 plans and only enlarge to 1/2 ".

Lastly in the picture, behind the table, are the wings stands for the spars. I plan to build both wings at once. These stands are a God send. Thank you to the builder Billy who provided them.

So that is my plan. Onward and upward, (well not yet anyway) :-(
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Thank you
John S

WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for thier use.

Extra dues paid 2017, worth every penny

RV9A- Status: tail feathers done less tips
Wings 50%
www.pilotjohnsrv9.blogspot.com

Last edited by PilotjohnS : 05-02-2017 at 06:50 PM.
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  #43  
Old 05-02-2017, 06:48 PM
PilotjohnS PilotjohnS is offline
 
Join Date: Jan 2016
Location: Los Angeles
Posts: 235
Default Harvesting Clecos for Wings

So have started building the wings. Not much to write about as everything started out well and went as per plans. Of course as I was saying this to myself I did find some "knowledge" was needed, and a few bandages. But I am getting ahead of myself.

Here is the bountiful harvest of clecos. And a warning. Just go ahead and order a thousand 3/32 clecos; if ordered all at once, there is a break in the price at a thousand, and the shipping is only one time. I am on my fourth cleco order; UPS is making bucks on shipping. Here is my cleco farm, ready for harvest. I am doing both wings at the same time, so this is only one of the two wings, Yes I ran out of clecos; the rest are coming in time for the tanks. Total clecos count will be slightly more than a thousand.

The main skins went on as per plans, no real drama, except I had a few holes in the rear spar where the holes in the rib, spar and skin didn't line up. Next time I need to make sure the rib holes line up with the rear spar during the rib to rear spar riveting. It is kind of tough to do it after the rib to spar rivets are in.

I didn't quite follow the plans when I put the J stringers in. I indeed drilled through my finger, even though the plans say "be careful don't drill through your finger". Speaking of J stringers, I had to make the short one a half inch longer to pick up the third rivet hole in the skin.

The leading edge ribs are notoriously for being hard to fit into the skin. After reading many blogs of those who came before, I decided to reshape the leading edge ribs. I once helped Bill Statler, a Lockheed SR71 wing designer, build a wing for a Reno racer. I recall him telling me the leading edge skin of a wing is very stiff due to the leading edge radius and there is no need for rivets, or ribs, inside this curved portion. I think he knew what he was talking about, so I decided to reshape the leading edge of the ribs slightly
To relieve the pressure. During my first attempt, when the virgin ribs were inserted into the leading edge skin, the rib webs were actually warping from straight in order to fit the leading edge radius of the pre bent skin. This is ugly, and causes scratches and bumps on the leading edge of the skin. When compared to the fiberglass tip, I think the pre-bent skins have too large of a leading edge radius causing a poor fit. Here is a picture of the virgin rib fitting onto the skin. Notice how the tab in front of the prepunched hole is holding the skin away.

I ended up making the leading edge radius of the ribs match the skin using a socket as shown below. I also rounded the tabs so they won't cause a dimple on the leading edge.

Everything fits much better. I am being careful to make the left and right wings the same, since this portion of the wing contributes to the flying qualities. Here is a picture of the reworked rib installed on the left leading edge. There is still a gap between the rib and the leading edge. I don't think it hurts anything, but I might throw some extra proseal in there when I do the tanks.

I also had an interference on one of the ribs to the spar rivets. This is the rib closest to the tank. Not hard to take care of. I am continuing on and looking forward to the Proseal Challenge.
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Thank you
John S

WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for thier use.

Extra dues paid 2017, worth every penny

RV9A- Status: tail feathers done less tips
Wings 50%
www.pilotjohnsrv9.blogspot.com

Last edited by PilotjohnS : 05-30-2017 at 07:22 AM.
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  #44  
Old 05-29-2017, 10:37 PM
PilotjohnS PilotjohnS is offline
 
Join Date: Jan 2016
Location: Los Angeles
Posts: 235
Default Tanks

I have been working on the fuel tanks. The Pro-seal is about to expire, so have been a mad man trying to get the tanks together.
Everything went per plans, but did some things that made it easier. Since I am doing both wings at the same time, the tooling and jigs get setup and taken down only once, so things go quick.

Since I ever so slightly re-profiled the leading edge, I made a template and verified the tank leading edge shape matched the outboard leading edge. The left wing I nailed perfectly, but the right I had to disassembly the ribs and tweak slightly. I also made the end ribs of the tank fit the curve of the skin as near perfect as possible to minimize the gap the Pro-seal has to fill in.



For the tank brackets I made a wood jig to hold the brackets and get the middle hole centered. Of course, all the brackets came from the factory exactly same length, except for two.Oh well.

The brackets are installed on the baffle and the line centered in the baffle holes. Then the remaining holes are drilled using the baffle as the drill guide. I found out that the baffle is not symmetrical; there is a top and bottom. In addition, the baffle flange orientation is mirrored on the right, but not shown explicitly on the plans, leading to additional confusion. You are warned.
After the brackets are drilled to the baffle they are installed on the tank, and the tank is installed on the wing for match drilling to the spar. There were several gotchas:
1) The baffle has a top and bottom, the prepunched holes are not symmetrical top to bottom.
2) The distance from the baffle to the spar is too close for clecos near the root. If I tried to use clecos to hold the tank skin to the baffle, the baffle and wing tank did not sit on the wing properly.
3) others have dimpled the baffle rivet holes; I don't see how this will not work on the RV9 since there is not enough clearance; I think the baffle rivet holes need to be countersunk per the plans.

After the brackets are match drilled to the spar, the riv-nuts are installed. I used a bolt and nut to drill the brackets for the rivets as in the pic. (The hole in the wood is for the nut to rest in.)

The rest went as per plans, nothing special. Prior to priming, I edge rolled the seams very slightly using my thumb technique. Not sure if this is needed, but I do not want any of the skins lifting off the spar and I could not find anyone on line who regretted doing this.

Lastly, I primed in prep for final assembly. The plans say only the bracket needs to be primed, but my minimum amount to mix easily is 50 ml. Not wanting to waste any, I primed the outside of the skins where they will rest on the spar and splice plate, the outside of the two end ribs, and the backside of the baffle. I am thinking the tanks may sweat when full of fuel, so I figure it wouldn't hurt to prime the outside that is exposed.

With all this work, I think I am ready for final assembly of the tanks. hope I have enough clecos ;-)
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Thank you
John S

WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for thier use.

Extra dues paid 2017, worth every penny

RV9A- Status: tail feathers done less tips
Wings 50%
www.pilotjohnsrv9.blogspot.com

Last edited by PilotjohnS : 06-19-2017 at 07:05 AM.
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  #45  
Old 06-18-2017, 09:58 AM
PilotjohnS PilotjohnS is offline
 
Join Date: Jan 2016
Location: Los Angeles
Posts: 235
Default Fuel Tanks - Part Duex, Is it a comedy or tragedy?

Tank assembly begins!
The bottom stiffeners were installed per the plans. I mixed up 1 gram of Proseal per linear inch, and this was just about right, taking into account losses from leaving stuff on the mixing plate, smeared on the ceiling, etc. Did I mention this stuff gets everywhere?

The next day, I mixed up another batch of Proseal per the instructions, and using the baggy technique, applied it to the ribs. I then cleco'd the ribs to the bottom skin using a cleco in every hole.





In the same session, I mixed a second batch and applied Proseal to the top of the ribs, inserted the tank into the frame and cleco'd the top of the skin to the ribs, again using a cleco in every hole. Then I smoothed the excess bleed out with the tip of the plastic knife, and let it set overnight. I added tape to keep the skins from spreading due to the Proseal's viscosity.



The next day, I came back and removed every cleco four at a time and used the #40 (-3) countersink to clean up the dimples. This removed the excess squeeze out and removed a sliver of aluminum to provide virgin material for the rivet to seal against.



I did not use "tank dies" but just the normal dimple dies. During riveting, the Proseal squeezed out during riveting and all that remained was what was needed to fill in the voids; Just my opinion.

The riveting went fine. I had to drill out a few clinchers, because the Proseal makes everything slippery. Also, if I didn't press the rivet down in the hole and squeeze out the excess, I would invariably get a rivet sitting proud. I used a hemostat to place the rivet in the hole filled with Proseal, pushing lightly to squeeze out the excess goop. Then I cleaned off the outside with a acetone-damped rag, cleaned the mushroom set, and riveted. I found using lower air pressure and feathering the trigger helped set the rivets without clinching. With 30 grams mixed, I was able to set 3 rows on the bottom, coat the shop heads and fillet the three ribs before the stuff started getting hard. It took me three nights over a week to get each skin on. With this fay sealing method, there was not a rush to set all the rivets in one session; I felt this made for much better results because I wasn't stressed trying to rivet everything before the Proseal set up.

The tanks skins and ribs are all riveted now. Looking back, I don't know why I was so apprehensive, but it was a learning experience. As a side note, I used MEK to clean the faying surfaces, but switched to acetone to remove the excess Proseal, to try and preserve my MEK for more important tasks; I can no longer buy MEK locally. (Time for a Vegas run, anybody up for Craps?)
__________________
Thank you
John S

WARNING! Information presented in this post is my opinion. All users of info have sole responsibility for determining accuracy or suitability for thier use.

Extra dues paid 2017, worth every penny

RV9A- Status: tail feathers done less tips
Wings 50%
www.pilotjohnsrv9.blogspot.com

Last edited by PilotjohnS : 06-19-2017 at 07:22 AM.
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  #46  
Old 06-18-2017, 11:06 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 6,502
Default A different perspective........

I also have some concerns about the use of tank dimple dies, but in my opinion, by installing the ribs and then waiting to rivet, you just moved the thick build-up of sealant from between the rivet and skin, to between the skin and the rib.

The squeeze force of a cleco is much lower than what is exerted when setting a rivet.
The sealant is very viscous and doesn't easily squeeze out from between the rib and skin.

I am pretty sure that just installing clecos and then letting the sealant cure before riveting leaves a much thicker layer of sealant between the rib and the skin. Far less desirable than the result attained if riveted wet, in my opinion.
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RV-6A (aka "Junkyard Special ")
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