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-   -   RV-3B Dave's in Colorado (https://vansairforce.net/community/showthread.php?t=85658)

rockwoodrv9 03-06-2013 09:33 AM

I will have to come over and go through your scrap pile! Having the first kit done must be a good feeling. I was in Denver Monday and Tues. I was going to come on up, but got stuck in meetings until late yesterday afternoon and had to drive home.

Next time I am in town, I want to see how you are going to set up your wing jigs and how you plan to build them. I like how you have everything put away already. I am working on my garage getting rid of a bunch of **** I don't need or want anymore to make more room.

My FWF kit is scheduled to be delivered tomorrow. That should be fun.

David Paule 03-06-2013 06:42 PM

Ppilotmike, I sent you a PM.

Rocky, I sent you an email.

Dave

ccrawford 03-06-2013 10:20 PM

Blue stuff
 
I just took the blue stuff off my tail kit, been on there since 2006. No problems taking it off, and moisture is not an issue here in Denver.

It was nice to have them protected while mounting so they didn't get all scratched up.

David Paule 03-07-2013 11:55 AM

That's what I figured. And seeing the clean parts that were in my kit but fabricated in 2009 and then stored in OR before shipping them to me, that kind of helped with the decision.

Dave

David Paule 03-16-2013 06:12 PM

Wing Jig Ready
 
With the tail put away, I designed and built this wing jig. For those of you who have the pre-punched kits, you won't need something this rigid, but the RV-3B requires something stiff upon which to support the wing's frame during construction.

As of today, the jig is trued and Bondoed to the garage floor. It awaits the angle brackets which actually support the spars. In the meantime I've started the rear spar. Thus, the game continues.

I had to use a wide angle setting to take the photo. In reality the legs are actually vertical and parallel to each other.



Almost forgot to mention that the reason for the four legs is to build both wings together. But you probably figured that out....

Dave

David Paule 03-24-2013 08:41 PM

Rear Spars
 
As I mentioned, I'm trying to build the wings together. Started with the assembly of the rear spars per the manual. This shows the root ends of them. I've left the holes pilot-drilled for the ribs but went ahead and riveted the other holes.

Incidentally, remember that this is an RV-3B. None of the parts shown here came pre-drilled or shaped, except that the rear spar itself arrives bent and one inch too long.

This was the first time I've riveted the long AN470AD4-11 rivets in the fork portion. They went okay with the pneumatic squeezer but that's about the minimum length that will work there, at least when using primer on those parts. The plans call for -10. Probably a -11.5 would be ideal, and I didn't try a -12.

The doublers at the aileron pushrod and tip are riveted too, using shorter rivets, but you'll have to use your imagination to see them - no photos today for that (mostly because they aren't very interesting).



Dave

rockwoodrv9 03-24-2013 09:01 PM

Those are some big rivets! How many times did you measure the spar to make sure you were supposed to cut it? I bet it took some convincing to make that cut! I have a 2x and 3x gun you can borrow if you need one. Looking good Dave.

David Paule 03-24-2013 09:48 PM

Rocky, I measured that cut about four times each spar, using two different measuring tools each. I figure I got it within half an inch or so. ;) Maybe even closer.

I understand that the extra inch is for attaching to the jig for the QB wings. I wanted to use it for my jig too, but it conflicts with the aileron hinge attachment later on. And at that point trimming it is more difficult because of the tip rib. I gave some thought to stretching the wing an inch but there were too many negative issues associated with that. That notion was easy to abandon.

I've got a decent 3X gun, but thanks. Didn't use it for these. The squeezer did fine at about 95 psi. They weren't really that hard to set.

Dave

David Paule 04-16-2013 06:56 PM

Ribs and Small Things
 
I've been working on small things:

Rib lightening holes cut, using the Malco HC-1 hole cutter. The photo shows the first practice cut, in a scrap seat rib. This tool is wonderful for cutting holes in aluminum. Easy and safe. What it doesn't do is cut a smooth cut, at least with the Sioux palm drill I was using. But a moment with a drum sander and that's done.



In the RV-3B standard build wings, there are a number of lightening holes to cut on just the ribs. There are also the usual various holes in the tank ribs too, generally much smaller, so a stepped bit was used for those.

Flanges had been previously squared.

Flanges marked for rivets and fluted in between them. No drilling here until I'm ready for the skins.

The tie-down fitting and it's aileron bellcrank mounting holes were all made and drilled. These were the first holes through the spar. These parts are now drying from the priming, and still need assembly.

The Duckworks landing light kit is on hand now. I bought two, so that I could install one on each wing. But after thinking it over, I think I'll just install one of them. After all, this will be a day VFR airplane, and that's sufficient for the rare time I'll be flying at night. I've still got to make the hole for the actual landing light. That'll wait till I have it because its installation directions don't include a pattern for cutting it out.

For this and the items below, some thought and figuring and head-scratching was required for each one of them.

I've got the "kit" for the pitot tube, which will be a scratch-built affair, somewhat cleaner and lighter than some of the ones we see. It needs to be built.

The stall warner is here too. It's a standard Van's kit and is designed for the -7, -8 and -9. It's very clearly NOT designed for the -3 or even the -3B, which I have. Some engineering is needed but not much. Good thing I'm an engineer. Now probably some of you will much prefer a full AOA system, and you might be right. I've never flown one. But this is a single-point AOA that warns when near the stall - that's all it does. My Cessna 180 has a similar one and it's great. I'll be comfortable with this thing, and safe. I hope.

The autopilot roll servo mount hasn't been ordered yet. I'm still undecided whether to install it in the fuselage, looks like it'll fit, or the right wing.

Dave

David Paule 04-28-2013 09:02 PM

I drilled the joints between the rear spar and the aft flanges of the main ribs today. This follows drilling the aft flange of the ribs earlier. I used a 12” #40 drill to back-drill through the rib flanges. It mostly went okay. It was more difficult where I had the mid-span or outer doublers, because the spar was .080 thick there.



The thing showing progress are the clecos atop the rear spars.

I'm using the main spars as (expensive) fixtures. And for reference, that table is 7' long by 3' wide, to give you an idea of the scale of things.

Previously, I'd mentioned that I needed to build the pitot tube. I wanted to get its mounting out of the way before attaching the ribs to anything. Here's the pitot tube - http://www.vansairforce.com/communit...ad.php?t=99034

Dave

David Paule 05-09-2013 09:29 AM

Main Ribs To The Front Spar
 
Starting with the right wing and using some bushings, I pilot-drilled the main ribs to the front spar. The first pass was through the web of the spar. Once that was done, I removed the ribs, drilled them to #30, and clecoed them to the spar.

With all of them clecoed, I used more bushings to pilot-drill for the 3/16 inch holes through the caps. Then I disassembled the ribs and drilled them out to the final size.

The next step was to remove all the ribs for deburring.

The left wing, shown here, is now ready for the first pass of pilot holes.



If you look closely you'll see that the ribs have all been drilled for the plastic bushings for the lights and stall warner and pitot lines. It's pretty easy to do that when the ribs are off the spars, and harder when they're on. You don't need to know the specific brands and models of these things yet, just roughly how many wires and hoses to allow for. The wires, etc., will go in before skinning the wings.

The holes in the rear spar to the ribs are all drilled but haven't been dimpled yet. I learned that my pneumatic squeezer will indeed dimple the .040 rear spar. The blue parts in the background are the flap brace and aileron fairing. The aileron fairing is the W-724 substitute that Randy Lervold recommended. They're here so that I could see which holes needed dimpling. At this stage of the game, I'm not convinced that the W-724 is a significant time-changer for a standard-build kit. But on its outboard end, it's already trimmed correctly for the aileron hinge fittings, and that's a plus, especially since the plans don't mention that at all.

The drill bushings were straight from the local hardware store. These are simple brass tubes that nest in one another. The one on the left was used for the #30 web holes, and the set of longer ones was used for the 3/16 inch holes in the spar caps. The smallest tube takes a 3/12 inch bit, shown, but not a #40 bit.



These have done a good job of protecting the front spar while drilling all those holes.

I keep them in a small parts ziplock bag in my drill drawer so I don't lose them. I hate losing things like that and I'm very good at it.

Dave

David Paule 06-12-2013 10:35 AM

Wings On Jig
 
Right now the wings are on the jig, and most of the nose ribs are mounted. Except for the tanks, there's one rib to go on either side.



The inboard-most nose ribs are now being mounted.

And yes, the garage does have windows on three sides.

Dave

David-aviator 06-16-2013 06:27 AM

Your garage is a real airplane factory, David. The process is different than assembling a pre punched kit, it is a genuine build and looks great.

Long live the -3!!

David Paule 06-27-2013 08:22 PM

Caught Me By Surprise
 
I was following the manual, kind of chugging quietly along, and suddenly came upon a section called "Fitting The Wing Skins." And the next thing I needed wasn't some small piece of 3/4 angle, it was the one-piece top main wing skins.

So out to the hangar I went, and back home I drove, with two skins and the walkway doubler piece in the truck. They are now in the shop and I'm wondering how on earth I'll manage them all by myself.

That wing crate still has a number of things in it that I haven't touched yet, but it's definitely looking more empty than it had been.

Dave

rockwoodrv9 06-27-2013 08:36 PM

After working with all the small parts, it must be strange getting to the big stuff! Have fun.

wirejock 06-30-2013 08:08 AM

help
 
I'll help any time. Fri-Sun. Call me if you need an extra pair of hands.

David Paule 06-30-2013 09:20 AM

RV-3B: More Think, Less Build
 
Thanks - gotta figure out just how to do this first. If the wing jig permitted having the wings horizontal, it would be a cinch, but it doesn't.

Looks like the first step will be to drill the skin holes that mate to the spar flange. I can drill the skin on the bench and use that to drill the flange. Then the rest should be straight-forward once I decide how to support the skin on the frame before drilling anything. I want to think the process through before committing to anything.

I made a simple edge-drilling jig. It's two pieces of 4130 plate, .093 thick and about 1.5" x 3" that make up the "bread" of the sandwich. The "filling" is a strip of .040 aluminum about 3" x 1/2" wide. I riveted these together with the aluminum on one side. Most of the space between the steel parts is empty. I drilled a #40 hole through both steel pieces that's 1/4" from the inside edge of the aluminum strip.

This gadget slips over the skin and lets me drill a hole a constant 1/4" distance from the edge. Or will once I start using it.

I used 4130 because I had the scrap on hand. The .040 aluminum is thick enough that it lets me keep the blue vinyl on the skin while I"m drilling. Making tools is a helpful way to think about how to build the airplane, and this tool is a general-purpose one.

And yes.... I acknowledge that my Whitney punch has a stop that would let me set this distance and simply punch these holes. I remembered that after I'd built this jig, sigh. I'll play with both and then decide which I want to use.

Dave

longranger 06-30-2013 03:38 PM

If you really want to work your wings horizontal, consider this type of fixture. Just a large bolt welded to heavy angle through a hole in the vertical square tubing. Each is easily leveled independently to ensure no twist in the spar:


Here they are in action. Saved me from having to lay on the floor to rivet the skin to the rear spar:

David Paule 07-23-2013 08:33 PM

Working away on the wing skins. The top main skins are now drilled to the wing and have been removed so that I could drill the bottom skins to the wing. Between skins, I double-checked the twist and to the limits of my measuring tools, it's still zero.

I made a dumb goof on the bottom skins and you've got to remember that this is an RV-3B and it's not pre-punched. I merrily went along drilling the skins and the spar flange, figuring I'd sort out the inspection hole covers later.

Wrong!

The inspection hole covers have dedicated fastener holes in the spar flange and now I've got rivet holes there instead. I'll have to sort that out and figure out how to do it. In the meantime, I've been making the inspection hole doublers and that's reasonably straightforward. The photo shows the ones for the right wing. At the top is the pattern for the outboard left wing. It has a strange ear on one side because it'll also double the pitot tube hole in the skin.



The outboard bottom skin is long enough for a double row of rivets at the splice. I had originally thought to use one row with 5/8" spacing (as shown in the plans) as it would be slightly lighter, and then realized that the double row and wider spacing would be smoother. Drag versus weight? In this case drag won the day.

Dave

David Paule 08-12-2013 07:29 PM

Now Leading...
 
Well, now I'm fitting the leading edges, anyway.

The main skins are drilled and clecoed, but not dimpled. The top and bottom skins are clecoed to the wing frame right now, and the leading edge skins have been drilled and clecoed to the top of the main spar.



I've drilled the top flanges of the nose ribs and plan to back-drill the leading edge skin to these flanges once I've got the skins pressed down to the nose ribs.

Dave

David Paule 09-07-2013 07:46 PM

Not Exactly As I'd Intended
 
When I pressed the leading edges down on the frames, the leading edge radius looked too large. Starting with the right one, the aft one in the photo, I was able to correct that and the leading edge then fit very nicely on the ribs. I drilled and clecoed the bottom of that side.

Looking more closely, I found that in between the ribs, that there was a flat spot just aft of the leading edge radius on the top in between the ribs. Since I'd rebent the leading edge radius that was clearly my fault. I attempted to add some more curvature in those areas and didn't succeed. Scratch the right-hand leading edge skin.

A friend came over to help with the left one. He had some excellent suggestions but it appeared inescapable that I'd have to rebend that leading edge radius too. Well, I botched it, putting that bend slightly out of position. That scrapped that leading edge skin too. This wasn't going the way I'd hoped.

I ordered new parts and started the tanks in the meantime. I had been looking forward to the tanks anyway - maybe it comes from playing in the mud when I was a small child, but gooey things are sometimes fun, and I'd enjoyed using Pro-Seal before.

Here are the ribs on the right-hand baffle, just getting started. The left one is at the same stage.



Dave

David Paule 09-15-2013 02:38 PM

Flood Clean-Up
 
I got hit less than a lot of folks and I'm pretty grateful for that. One of my friends lost everything, including an entire workshop with a lifetime's collection of tools.

Still, I've got a basement that's going to take some cleaning out, and the RV-3B project will be on hold while I do that. The RV-3B was not in the basement and was completely unaffected out in the garage.

At this point, the clean up is just a matter of labor and time, plus I get to practice my swearing.

I'll get back here when the project's underway again.

Dave

David Paule 09-23-2013 04:44 PM

Cool Parts Found While Cleaning the Basement
 
I had more water damage than expected, and had to remove more things than anticipated. And of course there's a bit of mold correction and I've been replacing things that can get moldy with things that can't.

Only four inches of water and silt can sure make a mess!

One good outcome was that I found a can of assorted AN hydraulic tube fittings that I'd "lost" down there. This is definitely RV-3 related. Plus I found a perfectly good helicopter airspeed indicator that I'd forgotten about which covers the RV-3B speed range. It's calibrated in knots, and if I use it, that'll make the decision between mph and knots. Since my Cessna 180 uses mph I'm tempted that direction, but of course the rest of the world uses knots so that's tempting, too.

Which reminds me that one day, back when I had my Corsair F-27 trimaran sailboat I was buried in work with a laser equipment client, and took a brief break from that to see what was going on at the trimaran forum. Someone was using the letters "nm" and I couldn't understand why nanometers, a common (and very tiny) measurement for laser development, would be used in sailboat operation. Too much work, eh?

Another potentially useful finding was one of those control stick grips with many switches. For emphasis - far too many switches. Too many for a day VFR airplane. This too is tempting, though I don't know what I'd do with all that switchology. For example, there's the common trim hat button. My RV-3B will have mechanical trim. This thing might be overkill. I haven't weighed it but it's not light.

Anyway, I'm still plugging away down in the basement but things are now at the stage where I'm looking towards completion. I can see it but I'm not there yet.

Dave

David Paule 10-06-2013 06:52 PM

Back To Building the Tanks
 
Looks like back when I was prepping my tank ribs, I drilled a vent hole on the inboard tank rib and then accidentally put that rib at the outboard end instead. Now I've got a nice hole that I've got to patch and a proper hole on the inboard rib to drill.

Yes, I'm back to work on the RV-3B after the flood. It's been about a month. I'm working on the tanks and I'd left all the parts where it was easy to resume. In the interim, I cleaned out my basement. That wasn't something I'd planned on doing all at once but the flood, which left about four inches of water down there, provided me with some motivation.

Today's job was fitting the fuel tank baffles and ribs and Z brackets to the wings. At the end of the day they are almost ready for fitting the tank skins, but still need the rib-to-rib spacing supports that will hold them straight.

You can see my extra hole on the left-most tank rib. This is the left wing. You can see a bit of the right wing in the background.



At the L.O.E. fly-in, it looked like it might be a good idea to install a second set of tie-down fittings near the wingtips. The standard tie downs are about 11 feet apart, and with airport tie-downs being 25 to 35 feet, the ropes are too shallow an angle to the airplane of the ground. This will help fix that.

I made a quick analysis (my line of work before retiring) and decided that the RV-3B spar web and flanges are strong enough for that load, although I can't say there's a lot of excess strength there for this.

Dave

Ironflight 10-06-2013 08:03 PM

The dimensions of the RV-3 do pose some interesting conundrums Dave - like tie-down ropes being too short (which is why we carry our own). Then again....I was talking to an Air Force Active Reserve mechanic yesterday (she was volunteer security at the airshow I was attending), and she allowed that the wingspan of the -3 would fit nicely inside a C-5A - with room to spare. That lead to the topic of an air launch..... :)

David Paule 11-10-2013 09:34 AM

Looks like I was too hasty getting back to the RV-3B after the flood. Some friends are needing a lot of assistance and I've been helping out, which takes up my time. And unfortunately there's another time-taker on the near horizon, too.

BUT -- I put the finish kit on order and the rest of the sole-source items. With a little luck, they'll all be safely in the hangar soon along with the engine and the fuselage kit.

And, in the moments when I've got time, I've been fitting the tank skins to the tank ribs. Remember that this is a non-pre-punched kit. It's not a sure thing.

Dave

David Paule 11-14-2013 05:08 PM

Right Hand Tank Skin Strapped Down
 
Recently, I’ve been having trouble getting the tank leading edge to lay fair. You can read about that in the RV-3 section, in a thread titled “Leading Edge Woes.” Here’s a photo of the affected area:



I apologize for the quality of the arrow I drew to the flat area just aft of the leading edge bend, but if you can follow it, that’s where the flat area is.

The right-hand tank skin is strapped down at the moment. The aft top edge is positioned so it butts to the top main skin.

Those 1” squares of .063 overlap the tank skin and hold it in place. That was a good idea from “27 Years of the RVator.” One of our tool companies should produce those and sell packets of them since I'm getting tired of making them. (If you’re a tool company looking for a simple useful product like this, the #40 hole is 1/4” from an edge, and all edges must be smooth and rounded. If they're straight too, that's a bonus sign of good quality)



I'm using the outboard skin to provide lateral positioning. As you can see, it's not strapped down.

Strapped like this, we can look at the inboard rib to see how it looks on the inside. Since I haven’t put in the access hole yet, we can’t see how any other ribs are fitting. But by feeling them from the outside, through the skin, they’re okay. The only area of concern is just immediately aft of the leading edge radius in between the ribs, as I've described.



To me, it looks like except for that area of trouble, the top is basically okay. While there's some gapping on the bottom, once the top has been drilled and clecoed, I should be able to make that go away. And if I'm careful, I'll be able to get that small gap on the top near the front to disappear.

Before drilling, I'll pull the skin off and double-check everything, especially my notes for where the ribs actually are.

Dave

rockwoodrv9 11-14-2013 06:37 PM

Looking good Dave. I can imagine how difficult it is to get the skin-ribs to line up and then get drilled. Have fun!

Ironflight 11-14-2013 06:58 PM

Hey David - in your past picture, that little gap on the upper surface between the rib and the skin is exactly where if have slight depressions on our QB wings - that's about where the forward-most rivet sits. If you can work a shim in there, you might have a smoother wing.

David Paule 11-14-2013 08:41 PM

Now that's darn good to know. Thanks! Actually, I wasn't sure if that was a mis-bent rib flange or it it was real.

And if you look very closely at the inboard edge of the skin right about in line with the upper forward notch (hate that word, as an old stress guy it's just not right) in the rib, you can see where the factory leading edge bend stops and the flat area of the skin starts. It only goes an inch or so. I hadn't noticed it on the photo before. Makes me wonder if it's an artifact of the rib after all - something to explore when I'm back home and working on it again.

Thanks again.

Incidentally, it was for the fun of sorting through these issues that I am building the slow-build RV-3B. Gotta say I'm getting my money's worth.

Dave

ppilotmike 11-15-2013 11:50 AM

Quote:

Originally Posted by David Paule (Post 826239)
Incidentally, it was for the fun of sorting through these issues that I am building the slow-build RV-3B. Gotta say I'm getting my money's worth.

Dave

You're sick! ...says the guy building a slow build 10. :D Not the same ballpark, but definitely the same sport...

AlphaCharlieBravo 11-15-2013 04:59 PM

Nice Mike!
A Pulp Fiction reference :D

David Paule 12-12-2013 08:10 PM

Santa Came AGAIN!
 
Second time in two years, I like the consistency. For the last event, refer back to post #31.

Here's Santa's sleigh and the green reindeer out in front of my hangar today:



Once we opened the door and hauled the goodies to the back of the hangar I got this photo of the Finish Kit - that's the fuselage kit to the left, and the wing box in the far background against the wall:



I've lately been ordering the sole-source items and this, the Vetterman exhaust and a few other things are on the list. Since I ordered a Todd's canopy, the canopy wasn't included as part of this finish kit. Neither was the spinner nor the tires. Why not the tires? Simply because I won't need them for at least a year and I can get them any time and they'll be fresh.

There is no FWF kit for the RV-3B, but I did include a few of the known needs, like the baffle kit and the FAB.

Initial impressions are that the fiberglass work is decent (don't know how it'll fit) and the kit for the baffles is new-style: pre-punched, trimmed, bent and with step-by-step instructions. Super!

Dave

rockwoodrv9 12-12-2013 08:17 PM

Pre Punched! Holy **** Dave, are you selling out!! haha!
I am finally back in Colorado for the holidays. I hope to get down to Denver to say hello to everyone.

I have just about settled on the Skyview for my panel. I really like what I read about how the GX3 autopilot is very nice, but the Skyview still looks like it fits me better.

Have fun and keep posting pictures of what real build is! Talk later.

David Paule 01-06-2014 08:10 PM

Leading Edge Skins, Still
 
Both tanks are now clecoed and still in place. I haven't unclecoed them yet. Here's the right tank:



The baffle will get drilled after I remove the tanks from the wing. Didn't want to risk damaging the spar.

I've started on the outboard skins. Having the tank skins inboard lets me match them. Since the outboard ribs don't extend to the leading edge (they stop an inch aft) I made some wooden braces to prevent pulling the leading edge down too far.



The vertical slot is to let me slip them over the threaded rod that hold the nose ribs in place. This way I can use one set on both wings.

Initially, I used the Howe Fittings and basically the same process I'd used on the tanks to hold the outboard skins in place. But no joy. For some reason, when I used them, the leading edge would consistently be about 1/2" below the leading edge of the tank skins. After a lot of head-scratching I determined that not using the Howe Fittings seems to work, and here's where I left the left outboard skin at close of shop tonight.



I'll have to untape the Howe Fittings before proceeding. Duct tape - builder's friend.

longranger 01-06-2014 09:34 PM

David,

I like your rib stiffeners! I'm going to copy that if/when I ever pick back up on my HRII project.

ppilotmike 01-07-2014 08:29 AM

I'm now on the 3B wagon too..
 
Quote:

Originally Posted by ppilotmike (Post 826424)
You're sick! ...says the guy building a slow build 10. :D Not the same ballpark, but definitely the same sport...

Well Dave,

As you know, I've recently aquired a partially completed RV-3B kit, which I plan to work on alongside my 10 build. I guess whatever "sickness" you have is apparently catching...;)

David Paule 01-12-2014 07:46 PM

I went back to the right-hand outboard skin and, using the Howe Fittings and a batten, got it to fit pretty well, so I went and drilled that skin to the ribs. These holes are drilled blind so I earned a few more gray beard hairs here.

Following that, I had the spice strips, that go between the tank and that outboard leading edge skin, in place and drilled to the ribs. I went ahead and drilled them to the tanks, then removed and deburred and dimpled them.

Here I'm trial-fitting a nutplate to the left one. Van's calls them "plate nuts" but as far as I know, no one else does. In addition to the cleco clamp, a #30 cleco does a nice job. Better, in fact, and that's what I'll use when I drill them, I think.



Dave

David Paule 01-21-2014 02:31 PM

Past Leading Edge Issue
 
Just wanted to mention here that I'm finally past the leading edge shape issues that I've had. Now I can move on with the wing. I've got a few related things, trimming edges, mostly, and then I'll be able to do something NEW for a change.

To David Howe - thanks again. Your advice was hugely helpful.

Dave

David Paule 01-28-2014 08:16 PM

Light Weight Tank Stiffeners
 
The tank stiffeners on the RV-3B wing tanks are 3/4 x 3/4 x .032 angle. I'm now making the parts that go inside the left tank, starting with these. I made a set that's mostly stock (I beveled the upper corners) and they weighed 153 grams for the set. These are the top batch.

Then I made a set from .016 that I bent up, adding a short flange to the top. With this flange and in spite of the thinner material, these have the same stiffness as the stock version. These weigh 99.0 grams and are the bottom set.



The difference is nearly 2 ounces per tank. Worth going after.

Dave


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