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Longeron bending - what *is* the "Orndorff method"?

Flying Scotsman

Well Known Member
We're getting ready to bend the longerons tomorrow evening, and I know that part of the key is "slow and steady", but I'm also curious...I keep seeing references to the "Orndorff method" that's on a tape or DVD somewhere. I don't really want to buy a whole video, plus wait for the delivery, etc. Can somebody just give me a quickie description of what in the heck this magical method is?
 
I second Seth

I'm telling you, I don't know how many hours I stressed over this. There was no way I was going to get those bends right I thought. I even convinced myself that I would take them to a machine shop and pay to have them bent.

Well, I ended up using a Crecent wrench, a digital protractor, a vice, and a mallet and did them myself. I too was done in about an hour.

In fact, just a few minutes ago I tried on the roll bar to my slider and it looks like I'm in spec with no tweaking of the frame required! So I guess I bent the longerons correctly a couple of years ago!

So far, I've found that things aren't nearly as hard as I imagined them.
 
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I third Seth

I remember the angst at the time, but just anchor your padded vise in an accessible location and whack away at it. Actually kind of therapeutic after a day of real work! :D
 
Bending

We're getting ready to bend the longerons tomorrow evening, and I know that part of the key is "slow and steady", but I'm also curious...I keep seeing references to the "Orndorff method" that's on a tape or DVD somewhere. I don't really want to buy a whole video, plus wait for the delivery, etc. Can somebody just give me a quickie description of what in the heck this magical method is?
is not really hard at all. It's the measurements that have to be correct at the get go. Measure, measure again, and then recheck. Make your measurements accurately and EXACTLY the same for both sides. The first bending will rattle your nerves a bit. Your have to use some brute force on it, it won't break-unless you're Godzilla. The second one is a piece of cake. Have a cold one afterwards and say, "that wasn't that bad."
Mike H 9A/8A
 
Ditto.

I won't say my second one is "overbent", but it was much easier after seeing how hard I could bang and pull on the first one and not get anything done :rolleyes:

I agree about the measurements. When I layed them into the longeron-less fuse and they slipped right into place, I first realized how critical the location of the bends were.

I actually found twisting the forward lower longerons more difficult than the upper ones.

You'll be fine. Get at it.


Joe
 
I started with a dead blow hammer and a 4" vise and ended up just using my hands and the vise. The hammer for me tended to put little kinks in the form where by hand I was able to get nice smooth bends. Duck tape the snot out of the vise jaws to prevent damage to the angle.

I agree, the most important thing is to get the measurements correct because if they are off, you will be wasting your time!

Use the template to get the curve close to correct and use the canopy deck to get it dead on. That is the part it must match anyway so make sure it fits the curve exact.

Use the side skins to get the downward bend at the front. Make this bend as sharp as you can to prevent edge distance problems when you drill this area to the side skins later.

The twist only needs to be close because you can tweak this later with a crescent wrench and using the firewall attach weldments to align them.

It took me about 45 minutes for the first one and about 20 minutes for the second one and they fell right in when they were called for on the fuse.

Get the canopy decks to fit nice!
oruuxs.jpg


The downward bend must match the side skins to get this all to fit nice. Make this bend as sharp as possible without kinking anything.
23uwzv5.jpg


The firewall brackets will help you find the correct twist. Use a crescent wrench on the end (support the area prior to the twist).
16iwk1s.jpg
 
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I just used my hands and it was no big deal compared to what I imagined. I did learn you need soft jaws or padding of some type to keep from nicking the underside of the angle on the corners of the vice jaws when pushing down.
 
  • sturdy vise with soft jaws
  • mark longeron accurately with measurements
  • seamers and wrench for providing twist (or removing twist)
  • large rubber mallet
  • cardboard template
  • digital level to measure twist
  • repeat until done

I actually was very gentle on the first longeron, and it took me a couple of hours. I think the 2nd one took less than 1/2 hour.
 
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longerons

Take the time to tweek em up. get them as perfect as possible, and same both sides. I am convinced that problems with canopy fit later on is from incorrect longeron symmetry. Been through this a couple of times. It's not hard at all, and the downward bend and twist in the front can be tweeked a little later when you fit up your firewall.

Regards, and good luck,
Chris
 
Orndorf Method...

I just bent the longerons for my 9A a couple of weeks ago. I do have the Orndorf DVD. He bends both of the Longerons at the same time in a padded vise. It is not much different from the Van's Method. You still have to tweak each one and match it to the template. Make sure the downward bend is nice and sharp so it matches the front side skins. I did mine in about an hour (for both sides). They can be further adjusted when you add the side skins. Don't sweat it.....They will turn out fine
 
Orndorf

I wish I saw the Orndof method before I bent mine. I just used Van's method with a dead blow hammer and a set of Harbor Freight vice pads. A few weeks later the new Orndorf RV-7 DVD showed up. Mine came out just fine but the Orndorf method solved one problem. When you bend the longeron using Vans method it has a natural tendency to try and twist since your are compressing one of the legs of the angle. Orndorf clamped the two longerons together and bent them at the same time. This canceled out the twisting tendency. Thats it.
 
Out of curiosity, how many degrees do they need to bend on the 7?

In the -10, it's a 2 degree bend.

(Plans say slightly under 2 degrees, but I found that slightly more than 2 degrees dropped them in place perfectly.)
 
Orndorff has you do three things:
1. Bend a curve
2. Bend a angle
3. Twist the longerons

This is his procedure:
1. Clamp Longerons together, it should look like a "T" http://i50.photobucket.com/albums/f307/Degan367/Bend.jpg
2. Mark them at 28 1/4"
3. Mark them at 38 7/16"
4. Mark them at 69 9/32"
5. Double check measurements against plans as they may have changed.

Place the longerons in vise with the "T" shape down in the vise. Vise does not need to be tight. Leave it loose enough to slide the longerons. Start at the 28 1/4" mark and use your body weight to bend the first curve and slide the longeron a few inches at a time and keep bending. If a clamp gets in the way, just move it. Put the F-712B canopy deck forward edge to the 28 ¼” mark on the longerons and use it as a template since the curve is already cut into it. Keep tweaking it until you get the curve you want.http://i50.photobucket.com/albums/f307/Degan367/Bend2.jpg

Now that the curve is complete, clamp the longerons at the 28 ¼” mark and tighten it in the vise. Grab the first longeron and pull it toward you until the distance is 2 ¾” away from the other longeron. http://i50.photobucket.com/albums/f307/Degan367/Bend1.jpg Then pull the remaining longeron until you measure the distances 5 ½” away from the first longeron. http://i50.photobucket.com/albums/f307/Degan367/Bend3.jpg As you bend the angle, the longerons wants to twist, you can fine tune the twist when you mount the longeron to the firewall.


When the curve and angle are done, you have to cut the notch at the other end of the longerons for the up rights post where the F-711 bulkheads go. Separate the longerons and orient them on your table so you can mark the top. http://i50.photobucket.com/albums/f307/Degan367/Bend4.jpg You only get one shot at this so mark the top of the longeron where you will cut the notch on each longeron. Use the F-714 Plate notch as a template to mark your longerons. Clamp the F-714 plate to the longerons. Make sure you position the end corner of the F-714 plate per the drawing. Orndorff figure out his measurement was 172 27/32” from the other end. DOUBLE CHECK YOUR OWN MEASUREMENTS. Do not cut the longerons off at the notches, you just have to notch the top and leave the side pieces of the longerons alone. http://i50.photobucket.com/albums/f307/Degan367/end1.jpg Once the notches are cut, there is a little bit of top longeron sticking past the end corner of the F-714 plate, just trim the top of each longeron and do not cut off the side piece of the longerons. http://i50.photobucket.com/albums/f307/Degan367/End.jpg

Orndorff really made this a easy process. I strongly suggest you purchase his DVDs since a picture is worth a million words and he shares lots of great information and tips. Use this procedure at your own risk as I cannot be held responsible if you muck it up. :)
 
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Thanks, guys! We got 'em done last night, thanks to my neighbor for his help and mallet-whacking ability (having an A&P and RV-8 builder next door is a freaking GODSEND). Curves match the deck dead on, and the angles match the skin perfectly. As usual, it was just a matter of gettin' 'er done...

Building on...gotta cut the notches, and then trim the J-channels tonight...
 
hey Naruto thank you very much!!!!!!! I just bent my longerons in 15 min! using ur write up! perfect! working with metal for 30 yrs also helped though!
love this forum!!!
i worried longer than it took to bend! no hammer or rubber mallet either. just pulled and used the side canapy deck as a guide.
onto the next worry, or part to build!
fred
 
So I've just finished all the bends in the longerons. Not easy but satisfying once complete. I'm not quite sure how these people bang it all out in an hour or so. I won't say how long it took me, but it was most definitely more than an hour...
Anyway, the question I now have is should one go ahead and put the rear notch for the F-711C in now per the suggestion above, or should you wait and do it per the Vans instruction, where this is not completed until the rear and center assemblies are joined? If it is to be done now, should the rear hole 2 5/32" from the end of the longeron be drilled and clecoed to the F-714 aft deck so that the F-711C notch can be accurately referenced against a correctly positioned aft deck? The reason I am a little hesitant about this is that Vans says not to drill the aft deck to the longeron's until you have rolled over the canoe, as this drilling controls the entire fuselage twist.
Confused.
Tom.
 
Notch

So I've just finished all the bends in the longerons. Not easy but satisfying once complete. I'm not quite sure how these people bang it all out in an hour or so. I won't say how long it took me, but it was most definitely more than an hour...
Anyway, the question I now have is should one go ahead and put the rear notch for the F-711C in now per the suggestion above, or should you wait and do it per the Vans instruction, where this is not completed until the rear and center assemblies are joined? If it is to be done now, should the rear hole 2 5/32" from the end of the longeron be drilled and clecoed to the F-714 aft deck so that the F-711C notch can be accurately referenced against a correctly positioned aft deck? The reason I am a little hesitant about this is that Vans says not to drill the aft deck to the longeron's until you have rolled over the canoe, as this drilling controls the entire fuselage twist.
Confused.
Tom.

Wait till you have the aft section riveted and don't drill any holes associated with the aft deck. You're correct, the aft deck locks in the fuse and even a tiny misalignment of a hole can twist the fuse.
Before you quit o the bending, make sure the bend exactly matches the aft decks.
 
Will be starting the bend soon. Are there any reviews on the Buller longeron bending dies. Priced at 39 bucks it seems a reasonable investment for a correct bend?
 
Dies

Will be starting the bend soon. Are there any reviews on the Buller longeron bending dies. Priced at 39 bucks it seems a reasonable investment for a correct bend?

Loved them but most RVs were built without. I documented the process on my blog if interested.
 
+1 .. the dies make life so easy in this part of the build. Worth every penny!
 
Thanks Larry. You've saved me again from making a tragic error.
Mark, regarding the dies, I would definitely use them again, but be sure that you fully understand the instructions. You must start with the forward end of the die two inches forward of the forward mark, otherwise the curve will not start in the right location. Also, expect to run over it a number of times with the die, slowly working up to your final bend and using consistent force for every squeeze as you move along the length of the curve. Use your cardboard template by all means to check the curve, however I've found I get better accuracy for fine tuning by holding the aft canopy deck up against the curve. Note that a section of the aft canopy deck is straight, so you have to place it in the right position to match the curve.
For the sharp bend, use the Orndorff method where you put them back to back in the vise, pull one out 2 3/4 from the other, then pull the other one the other way until you achieve 5 1/2" total separation at the end.
Good luck.
Tom.
 
Confused.....

Place the longerons in vise with the "T" shape down in the vise. Vise does not need to be tight. Leave it loose enough to slide the longerons. Start at the 28 1/4" mark and use your body weight to bend the first curve and slide the longeron a few inches at a time and keep bending.

Thankyou Naruto for your description on the Orndorff method this is helping me a lot.... I am a little confused though. My plans (RV7 DWG 18) state NO TWIST OR CURVE BETWEEN 28 1/4 AND 38 7/16. Are we to ignore this and start bending from the 28 1/4" mark as advised?

Thanks to anyone who can clarify.
 
No bend

Thankyou Naruto for your description on the Orndorff method this is helping me a lot.... I am a little confused though. My plans (RV7 DWG 18) state NO TWIST OR CURVE BETWEEN 28 1/4 AND 38 7/16. Are we to ignore this and start bending from the 28 1/4" mark as advised?

Thanks to anyone who can clarify.

You are correct. The span between 28 1/4 and 38 7/16 is straight. No bend or curve.
The sharp downward bend and twist is at 28 1/4.
The gentle Aft Deck curve runs from 38 7/16 to 69 9/32.
Whatever method you use, follow the plans and compare the bends to the associated parts.
Sharp bend should follow the edge of the side skin.
Gentle curve should match the Aft Deck.
 
Not as confused now...

You are correct. The span between 28 1/4 and 38 7/16 is straight. No bend or curve.
The sharp downward bend and twist is at 28 1/4.
The gentle Aft Deck curve runs from 38 7/16 to 69 9/32.
Whatever method you use, follow the plans and compare the bends to the associated parts.
Sharp bend should follow the edge of the side skin.
Gentle curve should match the Aft Deck.

Thanks for the clarification. I'm using the 'Orndorff method' and it is working great so far. I just need to put life on hold to spend more time on this project :)

Others have said it before me.... this forum rocks!
 
Of the many moments to remember in the 11-year building of my plane, I will never forget the sound a longeron makes after you throw it across the garage in frustration.
 
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