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Total Discouragement

Y

yankee-flyer

Well Known Member
By far the worst day in 3 months of steady 5 8-hour days per week. Spent 8 hours trying to make one longeron and probably just have an expensive piece of scrap. The ONLY way to open the angle to 95.4 degrees was to beat on it with a LARGE hammer. Squeezing didn't work and neither did a soft mallet. That opened it but it also caused the longeron to bend up-- the wrong way, Taking out the bend resulted in a wavy upper surface. Using the recommended "metric cresent wrench" to twist the forward part resulted in more bending and a wavy inside surface-- and also variation in the 95/4 degree angle. Gave up with an approximation of the recommended shape and tried putting in the curve. Soft Mallet had NO effect. Called Van's and was told to use a 3-4 pound hammer to bend the longeron. Bending in the curve was slow and also resulted in a bend downward in the longeron. Bending it back up takes out some of the curve and-- guess what-- adds more waves. Test fitting to clecoed verticals on the fuselage side indicates a pretty poor fit and some twist that's going to put a strange curve in the fuselage side. 8 hours on one longeron and no enthusiasm to start the right one.

I see no way to make an accurate piece with a hammer, vise, and crescent wrench. I'm not real enthusiastic about proceeding to assemble the airplane with a piece this poor in place-- two of them since I don't see any way to make the right one better.

Anybody making preformed longerons? If not. there may be a partially completed kit for sale.

Wayne 120241
Emp kit completed
Wing kit completed
Fuselage kit stall because of longerons
Avionics and finish kits in hand, engine enroute
 
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yankee-flyer said:
By far the worst day in 3 months of steady 5 8-hour days per week. Spent 8 hours trying to make one longeron and probably just have an expensive piece of scrap. The ONLY way to open the angle to 95.4 degrees was to beat on it with a LARGE hammer. Squeezing didn't work and neither did a soft mallet. That opened it but it also caused the longeron to bend up-- the wrong way, Taking out the bend resulted in a wavy upper surface. Using the recommended "metric cresent wrench" to twist the forward part resulted in more bending and a wavy inside surface-- and also variation in the 95/4 degree angle. Gave up with an approximation of the recommended shape and tried putting in the curve. Soft Mallet had NO effect. Called Van's and was told to use a 3-4 pound hammer to bend the longeron. Bending in the curve was slow and also resulted in a bend downward in the longeron. Bending it back up takes out some of the curve and-- guess what-- adds more waves. Test fitting to clecoed verticals on the fuselage side indicates a pretty poor fit and some twist that's going to put a strange curve in the fuselage side. 8 hours on one longeron and no enthusiasm to start the right one.

I see no way to make an accurate piece with a hammer, vise, and crescent wrench. I'm not real enthusiastic about proceeding to assemble the airplane with a piece this poor in place-- two of them since I don't see any way to make the right one better.

Anybody making preformed longerons? If not. there may be a partially completed kit for sale.

Wayne 120241
Emp kit completed
Wing kit completed
Fuselage kit stall because of longerons
Avionics and finish kits in hand, engine enroute
Click to expand...

Hi Wayne,

Very sorry to hear that you are having so much difficulty, they can be one of the harder parts to fabricate.

I had very good results by using a "Shrinker -- Stretcher", it is a tool used primarily on angle stock to cause a bend by lengthening or shortening one side of the angle stock. The tool has jaws with very fine teeth that grab the metal and either move together to shrink or apart to stretch, both movements are very small but with continued application along the angle they can move it a good bit. If you get it a little to far with the shrinker you can fix it with the stretcher. When done the surface of the metal will be just a little rough but a Scotch bright wheel or file will fix that quickly.

I am sure someone in the local Dayton EAA can help you find one to use, it only take about half an hour to do them both once you have the feel for the tool. Anyone who has one would be able to help you with it I am sure.

Have a better day.

Best regards,
Vern
 
Hang in there

yankee-flyer said:
I see no way to make an accurate piece with a hammer, vise, and crescent wrench.
Click to expand...

I don't know what the RV-12 longerons look like but I uttered just about the same words when it came to forming my RV-9A longeron. I was convinced that I would go to a metal shop and have them bent there.

Well, I ended up bending them myself in my garage using the caveman method described and here I am towards the end of my build and they came out just fine! I was amazed.

So, go slow and steady. Put them in the vice, put some pressure on them and whack them! Use a digital level to make sure you have the angles and twists correct. You WILL get it! Don't give up!
 
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what is the material?

I've got nearly a full set of -9 longeron stock here on the west side of Cleveland. I bought a standard wing kit, assuming a slow-build fuse, then bought a QB fuse. Let me know. Rick
 
You need help!!

Wayne, get Andy to help you--and don't give up! Bending the longerons is definitely easier with two people, and even more easier :D if your helper has experience.

It's been a while since I've done this, so I had to look at the notes in my builder's log. I wrote that my helper had to pull up and over while I was wailing away with the hammer. The angle was clamped in a vise and I used one of those shot-filled dead-blow hammers. I'm pretty sure I used the adjustable wrench to bend it around where it called for this as well. I (we) did the longerons like this for two planes and all four came out fine.

There will be setbacks in building. When things get so bad that you start looking for a dog to kick, just get away from it for a night and get back after it the next day. It's amazing the difference a day can make...especially if you have someone to help you with a solution. Good luck!
 
been there done that too

I was so disgusted with my first attempt that I ordered new angle and started all over again. I found the method Van's suggest too crude. I wound up using a hand arbor press that I bought for $25. A hydraulic bearing press would also work very well, and is easier to find. Using either one, you can put the correct amount of pressure exactly where you want it. On round 2 each longeron only took about an hour. There was a little tweaking later, but again it only took a short amount of time. With the way Van's suggests I had trouble getting the bend just where I wanted it.
 
I too thought the way to form the longerons was curde but it worked great for me. My dad helped me, as he has through the whole process, and we did each one in a little over an hour a piece. A little by little each one took shape.
I did not get the longerons with my slow build wing kit, that I purchased from someone else, and I went to the local metal shop and got two 25ft lengths of the correct material for $10/stick, and they were there the next day with no shipping costs!!
Don't get discouraged, there will always be setbacks and there are many willing to help out there. Good luck and take your time, you will get it.
Life is all about the adventure.
 
Bending angle is funny work. It doesn't do what you want and you have to be ready to correct as you go. My partner and I made the first longeron in less than an hour and thought how easy it was. THEN we tried the second! It seemed the second would not go where we wanted! In making the first curve, I struck it at an angle that counteracted the tendency to bend upward. On the second, I added to the problem. Left- and right-handedness issue. Note how the angle tries to bend (in the plane where you want it to remain straight) and strike to counteract that as you bend. I hope that makes sense. I used a large rubber hammer.

Bob Kelly
 
Great advice from many builders here. You are obviously quite frustrated. I suggest your first action is to put the tools down for a few days, soak in the expertise here, maybe take a trip out of town to relax, then return to your building. I have never built an airplane, but I have built many elaborate things in my life. Frustration is a common denominator in all extensive projects. How you handle the frustration will ultimately determine whether you finish the project or throw in the towel. I genuinely look forward to seeing a photo of your beautiful creation one day. Hang in there and don't be afraid to continue asking the questions.
 
diamond said:
Great advice from many builders here. You are obviously quite frustrated. I suggest your first action is to put the tools down for a few days, soak in the expertise here, maybe take a trip out of town to relax, then return to your building. I have never built an airplane, but I have built many elaborate things in my life. Frustration is a common denominator in all extensive projects. How you handle the frustration will ultimately determine whether you finish the project or throw in the towel. I genuinely look forward to seeing a photo of your beautiful creation one day. Hang in there and don't be afraid to continue asking the questions.
Click to expand...

Excellant advice. Longerons were the worst part for me also. I just could not get used to beating anything that hard that goes into a plane! I bought a 5 pound soft hammer from Harbor Freight and that helped. Take the the advice and use an extra hand.

Frustration seeps into the soul from time to time. Frustration (to me anyway) is usually caused by the plane work interferring with family and the real world stuff or vise-versa. Work out what ever is eating at you and build on. It's a process with unbelieable personal rewards at the end. Build on.
 
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Wow!

diamond said:
Great advice from many builders here. You are obviously quite frustrated. I suggest your first action is to put the tools down for a few days, soak in the expertise here, maybe take a trip out of town to relax, then return to your building. I have never built an airplane, but I have built many elaborate things in my life. Frustration is a common denominator in all extensive projects. How you handle the frustration will ultimately determine whether you finish the project or throw in the towel. I genuinely look forward to seeing a photo of your beautiful creation one day. Hang in there and don't be afraid to continue asking the questions.
Click to expand...

Wow, Diamond! What a perfect post. It is a concise, accurate, and profound summary of how we should be building not only our airplanes, but our lives. Upon returning from LOE last month, I came home to an unexpected family crisis which has me every bit as frustrated as the OP is with his longerons. As new as I am to this VAF community, I nevertheless keep returning here not just for the technical information everyone shares, but as well for the outstanding way you all live. Your advice, Diamond, is exactly what I needed to hear this morning in facing my own "building" problem.

Thank you.

Stephen
 
Gang,

Don't give up. As a friend once said about building, "It is not about the mistakes you make. It is about how you correct those mistakes."

God knows I made my share of mistakes and here is a picture of the pile of dead parts to prove it:
 
Like the regs say, homebuilding is supposed to "educational and recreational." You've got the educational part down...as Diamond said so well, be sure to keep it recreational as well.
 
I found the key to making good bends is going slow and applying adequate pre-load. The idea is not to try and use the hammer to make the bend. The intent is to establish the bend by clamping the angle in a vice near the bend point, applying pre-load and "setting" the bend established by the pre-load with firm taps of the hammer/mallet--no need to wail away at it like you would when working a forging on an anvil. And don't try to get the final bend in one go. I did my longerons solo, but having a partner would have made it a little easier. YMMV....
 
Longerons are just a battle, not the war!

Wayne,

When one runs a marathon, I am told there is a point where one "hits the wall." In the RV-12 build process my "wall" was when I got to the longerons. For the life of me I don't know why Van's doesn't pre bend these things at the factory where with the proper equipment it would take about 10 minutes - but they don't, and we have to deal with this in the field. As a first time builder I found this task nearly impossible, but eventually I did persevere. You will too. Go to my log and read the entries for 9-24-2009 through 9-29-2009. http://www.mykitlog.com/users/display_log.php?user=BigJohn&project=639&category=0&log=88882&row=44 Then jump to Movember 3-5 at: http://www.mykitlog.com/users/display_log.php?user=BigJohn&project=639&category=0&log=91827&row=14 There you will see how I had to make some more adjustments to the longerons after they were installed into the fuselage.

Bottom line is, my longerons are not pretty, as they got cosmetically scarred up though this ordeal, but they remain structurally sound. As long as you don't kink them I don't think the bending and rebending hurts them. Keep in mind they will be buried in the structure and not visible. Take the time now to make the bends as good as you can so you don't have to do what I did and make final adjustments after they are installed. Cleco the side frames and skins together to check the fit before committing to rivets. Plan on taking the longerons on and off the assembly many times for tweaking.

One thing that helped me get past this point was taking a day off from this task and working on something else for a while. You WILL get past this!

John
 
Auburntsts said:
I found the key to making good bends is going slow and applying adequate pre-load. The idea is not to try and use the hammer to make the bend. The intent is to establish the bend by clamping the angle in a vice near the bend point, applying pre-load and "setting" the bend established by the pre-load with firm taps of the hammer/mallet--no need to wail away at it like you would when working a forging on an anvil. And don't try to get the final bend in one go. I did my longerons solo, but having a partner would have made it a little easier. YMMV....
Click to expand...


That's what I did and I don't think it took longer than 10 minutes to do both sides.
 
put the hammer away

I bent the longerons for the 9A using a vice and my hands. No hammer! It is actually a very easy, controllable, and predictable process. You bend them both at the same time, so they come out identically. Bascially you mark them with a bunch of lines (for reference), clamp the (eventual) tops of them together with small C clamps, and use the vice to press against. Bend about every inch over the active area, and you get beautiful smooth curves. Each bend is tiny - you kind of press the clamped longerons against the corner of the vice until you feel it 'give' a little. Then move an inch and repeat.

My description isn't good - you can see this demonstrated in the Orndorff construction videos.

After they are perfectly bent (took me about 30 minutes to do both, I wasn't rusihing), then you use a big cresent wrench to put in the twist.

Put away that hammer - especially if you are frustrated!

Good Luck
 
As Bigjohn said, the longerons are a big challange. More for some than others. The reason I found it easier was I read how others had done it and learned from their experience. I only beat on the angles to open them up and I used the piece of excess angle that was was cut off as a sacrificial piece to beat on with a very heavy hammer. As far as bending was concerned, I simply put the angles in a vice and pulled. I advanced the angles in one inch increments throughout the designated bending area. Then checked with the template frequently. I too had to put them down and move on to something else from time to time. One should try to get them as close as possible since they determine the shape of the fuselage at that point. Also several parts will be attached to them so proper shape will mean an easier fit up.

I believe Van's spent considerable time finding fabrication tasks for the builders to perform so that this kit would meet the 51% Rule. At the time Van's designed the kit, the FAA had not yet removed the 20% fabrication requirement from the rule, so they were playing it safe by adding numerous little tasks here and there throughout the building process.

I found the fuel tank to be my biggest headache; and I'm still not done until I get the turtle deck in place so I can locate the filler neck. The I can perform the leak test and move on.

Art Pennanen
 
ARPENN said:
At the time Van's designed the kit, the FAA had not yet removed the 20% fabrication requirement from the rule, so they were playing it safe by adding numerous little tasks here and there throughout the building process.
Click to expand...
Just for clarification; There was never a 20% fabrication requirement for amateur-built aircraft. That was only a "proposal".
 
The road well travelled!!! I had to smile because I think all of us have been there...I can recall vividly my hands stinging the first time I loaded the longeron and smacked it with the mallet:eek:...Stop and regroup, there are more fun times ahead that will be just as if not more than this on the frustration meter...
 
IowaRV9Dreamer said:
After they are perfectly bent (took me about 30 minutes to do both, I wasn't rusihing), then you use a big cresent wrench to put in the twist.

Put away that hammer - especially if you are frustrated!

Good Luck
Click to expand...

If you didn't use a hammer, how did you open the angles? Just curious. And how in the world did you do this in 30 minutes? Took me three days with countless install/uninstalls, and they still weren't right. If this is a kit for the beginning builder, this is one piece that should have been done at the factory. Just my humble opinion.
 
John,
I guess the RV-9 does not require openning the angle to match the fuselage contour as it does on the 12.

Art Pennanen
 
Longeron

I opened the angle by squeezing it and a 3/4" rigid pipe coupling in a vise. The trick is to start at the very end of the angle and take small bites, a half inch at a time. If one puts the whole pipe coupling into the "V" of the angle, then it will be very difficult (if not impossible) to open two inches of angle at once. It is easier to repeatedly squeeze the coupling and angle, advancing in small increments of 1/2" or less.
As for bending the longeron to the shape of the fuselage, pre-load the angle almost to the point of permanently bending it, and then whack it next to the vise with a rubber mallet. Advance in small increments of 1 inch at a time.
Joe
 
yes you can separate them

I'm not familiar with the -12 longerons, but for -9/-7 you have to do 3 types of bends to go from angle stock to longeron:

I did all three using the vice, with no hammer:

1) clamp and bend against the vice as I described above to make the gentle curve - took about 30 mintues for both.

2) now put the still clamped longeron pair into the vice (clamp tight) and open it up - pull one longeron away from the other. You can measure the opening distance easily as you are opening them. You are shooting for double the distance on the plans between longeron tips (because you are bending both), with the opening symmetical about the vice. Took like 10 minutes for both.

3) separate the longerons from each other. Individually clamp each one into the vice and twist with the crescent wrench. Took about 5 minutes each.

One other tip you probably already know. The -9 at least came with a full scale paper template. It was OK, but the aft canopy deck was a better real-world "sheet metal template" for the active area of the gentle curve.

Good luck - I wish I had better pictures. If you can borrow an Orndorff -7/-9 fuselage video you can see this is how he did it. Sure worked well for me. I'm a first time builder and found the longerons really easy. I hope the canopy is as easy!
 
Required tools--

Sharpie and tape measure. Mark your bend lines and angles. Use a digital level to verify your angles when bending.

Good 5 or 6 inch vise mounted solid.
With lots of room on each side of it.


Two or three Bigger Cresent Wrenchs. With two sets of hands to control them.

Fair sized mallet, for beating on the angle.. Use the Cresent wrenchs to preload the angle with the right twist, and use the extra set of hands to pull on the angle in the right direction before beating it with the mallet.

Swallow your patients pill and get busy, it has been done many times with good results


Best
 
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