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Varieze Canard Bolt Torque and quick disconnect pins

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Hello All,

 

I am a new Varieze owner and can find no mention specifically of proper torque settings specifically for the Canard Bolts. This particular aircraft does not have nut plates but rather nylon lock nuts with large area washers. 

 

I am assuming that the 30-70 in/lbs is standard with the only mention in my literature being 3ft/lbs (36 in/lbs) for 1/4in bolts?

 

I am also desirous of learning about the best quick disconnect keeper for the elevator pushrod retainment. Is the Standard AN3 Bolt and a lock nut the best option? 

 

Thanks for any advice in advance.

 

M

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Posted (edited)

This chart would suggest 4-5 ft lbs but the elastic nut adds some drag so it's hard to use a torque wrench there.  I never use a torque wrench on them; just "tight" with a short wrench is about right

http://www.supercub.com/pdf/AN%20Bolt%20Torque.pdf

 

For the elevator pushrods, cut them in the middle, rivet about a 2"- 2.25" piece of aluminum rod 1"-1 1/8" into one of the ends, slip the other end over the rod, mark them and drill for a 3/16" clevis pin and cowling safety pin.  I do the same for aileron control rods.

http://www.aircraftspruce.com/menus/ha/pins.html

Edited by Kent Ashton

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I am assuming that the 30-70 in/lbs is standard with the only mention in my literature being 3ft/lbs (36 in/lbs) for 1/4in bolts?

 

AC43.13-1B, Chapter 7, table 7-1 lists torques for different bolt sizes and nut types. For tension nuts (the thicker ones, which are hopefully what you're using) it's 50 - 70 in-lb. But like Kent says, get a short handle wrench and make it "tight". You can calibrate your feel by tightening a few bolts with a torque wrench to 60 in-lb, then putting the short handle wrench on them and seeing how hard it is to just barely tighten them further. Then keep doing that.

 

I am also desirous of learning about the best quick disconnect keeper for the elevator pushrod retainment. Is the Standard AN3 Bolt and a lock nut the best option?

 

Assuming you already have an AL rod in the tubing and are using the AN-3 bolt/nut combo now, you can certainly do what Kent says - it's standard in the COZY. Or even if you don't - it's relatively easy to install per Kent's instructions (use 1/8" solid rivets and peen the head appropriately). Or you can just disconnect the pushrod from the intermediate belcrank just forward of the IP - it's relatively easy to reach, and you don't have to modify or install anything.

 

Do you have canardian resources near you in UT? When you need a CI, get in touch...

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Posted (edited)

Kent and Marc,

 

Thanks very much for the reply. I have new Canard attach Bolts and new certified elastic stop nuts (the big kind) as you all instructed. Marc, did we meet? I flew my Extra to the Kanab Fly In a few years ago with my son. I fly a Piaggio for work and am using the VEZ for commuting now. I purchased Chris Woodard's Varieze originally built by Mr. Sanders. I am enjoying the airplane thus far. There is a lot to learn.

 

I was also thinking of a couple of servos for the aircraft in the next few weeks. Do you all have any experience with the MGL Servos (not trio) and mounting adaptations?

 

Also do you know the dash number effective area for the 3/16 Clevis Pin? 29/32? For the proper fit...

 

Thanks,

Mark

Edited by VEZ75

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Pin needs to be a little more than 1/2”. A -17 should work (17/32”)

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Marc, did we meet? I flew my Extra to the Kanab Fly In a few years ago with my son.

 

Well, I've been to Kanab every year for the past bunch, so it's certainly possible.

 

I purchased Chris Woodard's Varieze originally built by Mr. Sanders. I am enjoying the airplane thus far. There is a lot to learn.

 

Great - I was wondering where Burrall's plane had ended up. And it is certainly a learning experience. Good on you for flying Avantis - Maybe you could bring one to Kanab this year and give rides :-).

 

I was also thinking of a couple of servos for the aircraft in the next few weeks. Do you all have any experience with the MGL Servos (not trio) and mounting adaptations?

 

Uggghhh. I won't give my whole spiel on my position on MGL equipment. I just hope you don't ever plane to fly in IMC. But their servos should be essentially the same as everyone else's. Most folks mount the roll servo on the firewall, and have it push/pull one of the pushrods, and the pitch servo will usually go on the side of the fuselage forward of the IP and push/pull on the pitch pushrod from the intermediate belcrank (which only exists on VE's) to the canard belcrank.

 

But there are many variations.

 

Also do you know the dash number effective area for the 3/16 Clevis Pin? 29/32? For the proper fit...

 

Do you not have a copy of the VE plans? You really need to have a set, if you're going to own and maintain the plane.

 

Page 19-6, figure on the lower right, has the answer to the previous question about quick disconnects and also indicates what clevis pin and safety pin to use. They call for an AN393-19 clevis and an AN416-1 safety, and they say to install it through the lower end of the pushrod, just fwd of the intermediate belcrank. Page 19-5 shows how the whole assembly goes together.

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Posted (edited)

You are citing pages for these requests that I am asking. Where do I find a set of plans if I do not possess them?

 

Thanks,

Mark

Edited by VEZ75

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You might download the Long-ez builder's manual here.  It's not exactly a Varieze but will probably help.

http://www.aryjglantz.com/p/documents.html

 

P. 16-3 of the manual shows the control tube connector we were talking about.  

 

I had a little problem getting the manual to open.  Had to change some permissions or something but eventually got it to open.

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You are citing pages for these requests that I am asking. Where do I find a set of plans if I do not possess them?

 

 

Long-EZ plans are almost useless for a Varieze - there's no point in downloading them. The pitch control system is different, as are many different sections of the plane.

 

You should have gotten the plans from Chris or Burrall when you purchased the plane, but if you didn't and they don't have them to give you, then I can share a set of PDF plans sets with you (since RAF no longer cares about copyright infringement and has essentially put all of their documentation into the public domain).

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Marc,

 

Appreciate that. I have spoken with Chris and we are working that out. I have replaced the Canard Bolts with new AN4-13A and new Lock Nuts Part AN365-428A. The bolts that I removed had a lot of the plating worn over time, and the Lock Nuts looked a lot thinner than what I have replaced them with (Maybe 1-2mm). I purchased a 5-40 in lb Husky torque 1/4 in drive yesterday and tightened to spec then added another 1/5 turn. I am fairly nervous about all of this to be honest as there is no nut plate. I have used 6 nuts up trying to get it to what I think is just right. I know that its just paranoia but do these parts and my method sound acceptable? I kinda don't want to mess this up as the accident report from a previous aircraft has sufficiently scared me. O the unknowns of a new airplane.

 

Thanks,

Mark

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Posted (edited)

The use of a nutplate is a weak point IMO.  It can twist, the threads can slowly get stripped out; that's happened.  You are better off just using bolts and nuts.  The usual nuts are either elastic full-height locknut AN365-428A.   There is a low-height version of the elastic nut you might have gotten but the full-height is better for this application.  Elastic locknuts generally get replaced when they begin to lose their drag.

http://www.aircraftspruce.com/pages/ha/nut_an365/an365_2.php

 

or all metal locknuts.  AN363-XX

http://www.aircraftspruce.com/pages/ha/nut_hex/an363.php

 

Use wide washers to get clamping force.  

 

You are fretting too much over torque.  The purpose of torque is to load the threads on a simple nut so the nut doesn't loosen and back off and to tighten it without stripping the threads.  An elastic or metal locknut here serves the purpose of preventing the nut/bolt combination from backing off so what you're trying to do is tighten enough to provide adequate clamping force between the lift tab and the F-22.   A torque setting does not measure clamping force so trying to torque things like that with a torque wrench is OK, but it's not really measuring what you want to measure.  Just get them tight so there is no movement possible between the lift tab and the F-22 and it will be OK.  Marc will correct me if I'm wrong.  :-)

Edited by Kent Ashton

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The bolts that I removed had a lot of the plating worn over time...

 

Unless there's corrosion, plating being worn isn't a problem, but obviously new bolts can't hurt anything.

 

and the Lock Nuts looked a lot thinner than what I have replaced them with (Maybe 1-2mm).

 

I'm going to guess that what was on there was AN364 low profile lock nuts, rather than the AN365 full height nuts. Not the right nuts, and I certainly recommend the full height nuts. Obviously it worked, but still... The right nuts allow you to use the full torque specification for the bolts, which the low profile ones do not.

 

I purchased a 5-40 in lb Husky torque 1/4 in drive...

 

in-lb or ft-lb? 40 in-lb is almost nothing...

 

yesterday and tightened to spec then added another 1/5 turn.

 

More is not better. If there's a spec, and you used it, why would you tighten more? What spec did you use?

 

I am fairly nervous about all of this to be honest as there is no nut plate.

Personally, I like nut-plates for the ease of installation/removal, but there's nothing wrong with nuts in this situation.

 

I have used 6 nuts up trying to get it to what I think is just right.

 

Just right is whatever the torque spec is. From Table 7-1 in Chapter 7 of AC43.13-1B, assuming the bolts are primarily loaded in tension, you'd use a torque spec of 100 in-lb (~8 ft-lb) for the AN365 nuts. And you don't have to replace a locking nut just because you used it once - basically, if you can't screw or unscrew it onto the bolt with your fingers, it's got enough residual locking torque to use again.

 

I know that its just paranoia but do these parts and my method sound acceptable? I kinda don't want to mess this up as the accident report from a previous aircraft has sufficiently scared me. O the unknowns of a new airplane.

 

Believe and use the specifications - don't try to do "more". New bolts and the correct nuts are great, and it's good that you're being careful and thoughtful. Always better than the alternative... And I agree with Kent about the wide area washers under the bolt heads, but I've never seen an issue with AN960 washers, so that's just more conservativism.

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Marc,
 
In your first response to me, you indicated that 50-70 in/lbs with thicker tension AN365-428A nuts was proper (This is what I am using now). A little later in the post, it was advised that I tighten with a smaller wrench in small increments by feel which is why I tightened to 40 in/lbs and gave it a little extra (only 1/5 turn.....which happened to be around 47 in/lbs total. I bought a new Torque wrench last night after my post and practiced to get exactly 5 ft/lbs (60in/lbs) on a non-project sample. This was specified in the previous post. The bolt are now 60 in/lbs +- 4%. Now why 100 in/lbs?
 
I believe the specification to the letter at 50-70 in/lbs. This is the table that I found....What am I missing with the 8 ft/lbs number? I started at near 50-70 and now its 100 in/lbs. This is what I was trying to avoid......improper info on my part during application. SO......I should be using the Advisory Circular then? Thanks for helping me to understand. I know that this is trivial and we are talking about small numbers, but I like to at least have the most accurate technique and procedure. I hope this makes sense as to why I am confused.

 

I did read a previous thread that indicated 10 fl/lbs was way too much. Bordering on crushing the structure.

AN Bolt Torque.pdf

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In your first response to me, you indicated that 50-70 in/lbs with thicker tension AN365-428A nuts... The bolt are now 60 in/lbs +- 4%. Now why 100 in/lbs?

Good question. Because on further reflection, although the canard lift tab bolts are in single shear, part of their purpose it to put substantial friction force between the lift tab and F-22 in order to transfer the lift loads. Because, if the F-22 was build correctly, there's an AL bushing that the bolt/nut squeezes (and the plans call for an AN4-12A bolt, not a 13A, so be careful that you're not bottoming out the bolt threads) you can't crush the foam/fiberglass structure of the F-22 bulkhead, I think that it's better to go tighter than just a "bolt in shear" level.

 

But I don't think that there's anything unsafe about the 50 - 70 in-lb range - you just get more margin if you go to the maximum capability of the bolt and nut, which is 100 in-lb.

 

I'm sorry for revising my thought process as I went along and confusing you. As long as you've got more than 50 in-lb on the bolt, you'll be safe.

 

Sadly, the plane (VE, LE, COZY) don't spec a torque for these bolts, which are just about the most important ones in the plane :-).

 

I believe the specification to the letter at 50-70 in/lbs. This is the table that I found...

This is what I was trying to avoid......improper info on my part during application.

So that table you found is 1/2 of Table 7-1 in Chapter 7 of AC43.13-1B (downloadable from the FAA, and an indispensable reference tool). It's only the torque levels for bolts in shear - it doesn't show the maximum allowable torque limits for bolts in tension, which is where the 100 in-lb. comes from.

 

SO......I should be using the Advisory Circular then?

 

Unless there's some good reason to use some random document found on the web (like the AC doesn't mention the issue and there's no other master source), AC43.13-1B is the canonical document for aircraft maintenance.

 

I did read a previous thread that indicated 10 fl/lbs was way too much. Bordering on crushing the structure.

You won't crush the structure of the VE if the bushing was installed during the build process, but you WILL deform the bolt, possibly stripping the threads and/or stretching the bolt. 100 in-lb is 8 and a tiny bit ft-lb, so yeah - 10 ft-lb (not 10 ft/lb) is way too much and will harm the bolts.

 

Sorry for confusing you and changing the story midstream. Basically, in this case, anything between 50 in-lb (lowest # to use for bolts in shear with an AN365 nut) and 100 in-lb (highest # to use without harming the bolt/nut) will keep your canard on the airplane safely. Which is why I rarely use a torque wrench to install the bolts - once I know by feel with a certain wrench how much 100 in-lb is, I just go somewhat less than that, and call it good.

 

Hope this is clearer than mud.

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Marc,

 

Thanks for taking the time to clear it up. It makes better sense now. Using the -13 on my particular airplane gives me 2 threads that I can see. Also, per the document that I attached, should I be adding 15 or so in/lbs for the rotational drag of the stop nut? Really appreciate you taking the time to clear this up, it gives me better peace of mind.

 

Mark

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Using the -13 on my particular airplane gives me 2 threads that I can see.

Good enough.

 

Also, per the document that I attached, should I be adding 15 or so in/lbs for the rotational drag of the stop nut?

 

I'm slightly suspicious of the values noted in the document - they seem high for fiber lock nuts. But I've never done a study, so I can't say for sure.

 

You would add some torque based on the value the torque wrench measures before the bolt/nut is tight. The "tare" torque of lock nuts is actually pretty low after the first installation. Even for metal locking nuts, the MAXIMUM tare torque for 1/4-28 nuts may be around 30 in-lb for the first install, but then drops to around 2.5 - 5 in-lb for subsequent installs. See Page D-38 of this document:

 

http://tinelok.com/wp-content/uploads/2013/09/IFI-100-Prevailing-Torque-Locknuts.pdf

 

for more info. The fiber locknuts will be lower in "tare" torque, so I'd say to ignore the tare torque if the nut's been used before and still can't be turned by hand, and use the torque wrench measured value of "tare" torque on the first installation. But it certainly can't hurt to see what torque is required on the torque wrench to turn the nut/bolt prior to getting tight, and then add that value to the required torque value to get the necessary reading on the wrench.

 

For further confusion, Table 7-2 of Chapter 7 of AC-43.13-1B gives minimum prevailing torques (tare) for AN365 nuts, but only for nuts larger than 7/16" (go figure). But the 7/16" nut has a minimum value of 8 in-lb, which would lead me to believe that the AN4 (1/4") nut would be in the 3 - 5 in-lb range, as indicated above.

 

So, if you're shooting for 50 - 100 in-lb as a range, and you set your wrench to 80 in-lb, you can't go wrong - you won't break anything and you'll have more than enough torque no matter what the prevailing nut torque or nut type is.

 

Is this getting any clearer?  :-).

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O yes.....much clearer. I flew today and didn't die as well, so thats awesome. 

 

I wanted to ask you if its normal for an O-200 to have RPM ranges that are transient zones not to be run continuously, perhaps dependent on airspeed? I can find no mention of this but around 2000 rpm, the airplane feels not happy as it decelerates from 210 to 140ish. This little airplane continues to surprise me. 

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...if its normal for an O-200 to have RPM ranges that are transient zones not to be run continuously...

Unless the POH for the engine or the airplane states a restricted area for continuous operation, no. Generally, RPM restrictions are put onto engine/prop combinations, not an engine alone (although there are always exceptions). And since there's no way for the designer to have a clue what prop you're going to have, Burt didn't put any restrictions on RPM for the O-200 on a VE.

 

... around 2000 rpm, the airplane feels not happy as it decelerates from 210 to 140ish.

 

OK, so precision in language will help a great deal in diagnosis. We couldn't possibly begin to discern what an airplane that "feels not happy" might mean in the context of vibration, aerodynamic behavior, oil usage/leakage, canard/wing/winglet motion, control system forces, or any of the other things that might not be optimal on an airplane. Nor what "210 to 140" means. IAS? TAS? Kts? mph? Descending? Climbing?

 

Precisely what are the symptoms, and under what circumstances, and how do they differ from what the airplane does in other circumstances?

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As the aircraft decelerates from max structural cruising speed in a sustained engine under-speed condition from 210 MPH IAS through 140 MPH IAS, a low frequency vibration is felt in the seat of my pants much the same as the two transient RPM Ranges in the Piaggio.

 

I can tell that it is coming, it gets more pronounced, then subsided in a linear fashion. This only takes place during deceleration at 2000 rpm +-100 rpm. It feels strictly engine/spinny thingy oriented. No Spinner is installed.

 

It's not that the airplane cannot be operated there, but rather feel obliged to pass through those particular zones expeditiously. Much the same as rotor rpm transient zones for helicopters, the ones that start the funky chicken dance. Chinooks have this well documented on the ground.

 

Its not really a huge deal, I just am curious if this is a mannerism that is unique to my airplane or something experienced in a fleet. I could speculate but my O-200 experience is almost 10 full hours now, so I'm not going to.

 

I emailed Gary to start a 63 X 69. I have a 62 X 68 on an 8 in Extension. 

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This only takes place during deceleration at 2000 rpm +-100 rpm.

 

Does it occur on the ground at 2K RPM? If you bring the engine to idle in the air, then accelerate again, does it happen at 2K RPM?

 

What's "low frequency"? Do the canard tips oscillate at the low frequency? Is it only a "buzz" in the seat of your pants? How pronounced is the vibration? Bad enough that you can't read the instruments?

 

Have you looked at the engine mount rubbers to see if they're in decent shape? Is there something loose in the airplane that's flapping around? As you change IAS, does the frequency of the vibration change? If you decelerate through that speed range at 1800 RPM, does the same thing happen? If you decelerate at speeds below 140 mph ias but at 2K RPM, does the same thing happen? If you accelerate through that speed range at any RPM, does the same thing happen?

 

Have you asked Chris or Burrall about this? They've got about a zillion hours in that plane together - I'm sure they know it like the back of their hands...

 

Without feeling it, hearing it or seeing it, it's VERY hard to say if there's even anything abnormal, much less what it might be...

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Marc,

 

I am in the process of taking go pro footage and trying to understand this better. I will have a better report soon. Appreciate those questions, they made me think more in depth about what it is that I am feeling.

 

Mark

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You won't crush the structure of the VE if the bushing was installed during the build process, but you WILL deform the bolt, possibly stripping the threads and/or stretching the bolt. 100 in-lb is 8 and a tiny bit ft-lb, so yeah - 10 ft-lb (not 10 ft/lb) is way too much and will harm the bolts.

 

 

Unless, like on my VariEze, a bushing was used that is too short. I think both bushings are around 0.77" long which matches F22 on one side, but on the other side F22 is 0.825" thick. Tightening of that side over the last 40 years has lead to crushing of the foam and cupping of the wide area washer under the bolt head. I made a new bushing of the correct length to fix it.

 

The reason for the difference in thicknesses is a build-up on the front face of F22, presumably to get the canard perpendicular to the aircraft centerline. Maybe the bushings were made prior to that and never adjusted to account for it?

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