Newbie Question

[Sabre]

I had a question that is likely somewhere in the forum but as yet I have not found it by searching. Now that the rain has started I can finally spend some quality time on the project! I was working on the aileron idler bellcrank and after removing the powder coating and squaring the tabs to each other I can get the washers and bellcrank installed into the fuselage. The question concerns torqueing the bolt, if torqued to the 20 – 25 in lbs specified for this bolt nut combination the tabs compress binding the assembly. Obviously I’m missing something. I have enjoyed the hundreds of post I've read so far and learned much in the process. Thanks for your input.

[Dave S]

Hi Greg,

Look at the torque as a limit not to exceed rather than a specification to meet. A lot of A & Ps would not even use a torque wrench in a situation like this......The goal is to tighten the nut so you get the desired effect which is minimum end play on the bearing and no binding while not exceeding the torque limit of the bolt/nut. For a new person it is best to tighten with a torque wrench to make sure the torque limit is not exceeded in the process. This is not like tightening a spark plug or wheel bolt where an exact torque is mandatory.

You may also find that using thin washers or stacking thin washers might help with getting the fit you want.

I don't know if you are using a nylock nut or a castle nut with a drilled head bolt; but, the goal is the same.

After operating my plane for a while I found that I could adjust the tension on items like this (belcranks) as parts wore in.

Sincerely,

Dave S

KF 7 trigear
912ULS Warp Drive

[Sabre]

Thanks Dave. I suspected this but could not verify it with any of the documentation I have access to. Thanks for your response. Greg

[Esser]

Has anyone switched out the nuts and bolts for a drilled bolt with a castle nut and safety wire?

[Dave S]

Esser,

Affirmative. Drilled bolts were used for all control rod ends and bushings for N128DD.

Sincerely,

Dave S

[n85ae]

Still on cup 1 of coffee, but isn't this a bolt with a castle nut, and a cotter pin? If so just tighten it until it "feels right", and put in the cotter pin.

Regards,
Jeff Hays


I had a question that is likely somewhere in the forum but as yet I have not found it by searching. Now that the rain has started I can finally spend some quality time on the project! I was working on the aileron idler bellcrank and after removing the powder coating and squaring the tabs to each other I can get the washers and bellcrank installed into the fuselage. The question concerns torqueing the bolt, if torqued to the 20 – 25 in lbs specified for this bolt nut combination the tabs compress binding the assembly. Obviously I’m missing something. I have enjoyed the hundreds of post I've read so far and learned much in the process. Thanks for your input.

[Esser]

Mine are all Nyloc but I think I will be switching to castlenuts.

[Av8r3400]

A rod end bearing only requires a locking nut because there is no movement on the hardware. A cotter pin and castle nut is only needed when the hardware is the rotation element of the joint.

A rod end bearing should be tightened in it's mating fork such that the ball of the bearing does not turn against the hardware. The ball should only turn in it's socket.

Using castle nuts on a rod end bearing is not the correct usage of hardware and will result in unwanted wear on the bolt itself instead of the ball of the bearing as it's design intended.

[Dave S]

During the construction of the aircraft, I had three EAA tech counselor inspections. Two of them were done by a person who was a long time Airline A & P (& RV builder), the other was an EAA tech counselor, FAA employee who worked on certification of in service components for transport aircraft. The DAR also liked the drilled bolts. The A & P tech counselor suggested the switch to drilled bolts/castle nuts & cotter keys. What I didn't put in my original post on the subject was the fact that this also included the use of select fitting, as needed, of thin washers to allow the correct tension ("Feels right") and have correct cotter pin alignment.

For what it's worth,

Sincerely,

Dave S
KF7 Trigear

[Dave Holl]

Dave
I did the same on my installation and it's what I expect to see on Boeing and Airbus installations with flying controls
Dave

[Av8r3400]

We can disagree, I guess.

I will go on what I was instructed in my LSA Repairman class. After a long discussion on this very subject, the instructor (an A&P with AI) made perfect sense to my engineering perspective. A mechanically locked nut and bolt, by definition, must be loosened to align the cotter pin. This will allow the hardened ball of the rod end bearing to rotate on the soft bolt shaft, which will cause wear.

Using a nyloc bolt allows the hardware to be tight on the flat sides of the ball in the bearing, making this hardened ball rotate in the socket it was designed to move in. There is no movement of the hardware in relation to the ball or the actuating fork in the joint. So there is no concern of loosening the nut on the bolt or grinding wear thinning the shaft of the bolt.

[SkyPirate]

I agree with you Av8r3400, my
Mechanical mindset says the same thing, if it were tapered like a tie rod end it would be a different story because then a castle nut and cotter pin would be exceptable because there are 2 forces working to keep it in check , where the bore of the hiem joint is not tapered you must rely on friction of the nut and bolt compressing the flat sides of the ball/ bearing

[airlina]

What swayed me to the castle nut camp on my Series 5 was walkarounds on my work airplane. If Boeing did it I figured it had to be tried and true.

[Sabre]

Thanks for all the replies, interesting discussion. I had another question: As I'm working through hooking up the connecting rods I came to the rear belcrank for the elevator. With everything square I can only get one washer (960-10L) between the bearings and the mounting tabs (as in one on one side of the assembly), there should be two, one on each side between the mounting tab and bearing surface. This fit is perfect with the exception of missing a washer. Is it preferred to remove material from the bearing surface? Removing material from the mounting tab doesn’t seem like a good choice although I removed the powder coating from both tabs on the inside. Is not having a washer satisfactory on one side? Manual states to shim as required but I am assuming that means to use a combination of 960-10 and 960-10L to achieve the proper fit with a washer on both side of the bearing mounting tab surfaces? Thanks for your input.

[Av8r3400]

I would highly recommend NOT removing material from the bearing ball.

In this instance I would bend open the fork enough to get a thin washer (960-10L) on either side of the bearing ball.

[mr bill]

Having a washer on one side, is shimming as required. Having a washer on one side is ok.

[Sabre]

I returned to finishing the tail assembly after working on the fuselage while playing with Superfil which like Esser I super-suck at but, sandpaper allowed me to in the end be victorious.

The issue I have run into is that when I install the trim motor assembly in the lower fuselage mounting tabs I find that at the other end the rod end & scissor links are out of alignment by a little more than the width of the rod end (+.4”). The right side of the rod end is laying against the outside of the left side mounting tab on the fuselage.

I’m not too excited with the options I have come up with to remedy the problem and have not found any posts that deal with this. I’m hoping I’m missing the simple solution. I would appreciate an any ideas.

Thanks, Greg

[Danzer1]

Greg,

I understand your description, but could you post a picture or two to show how you have it assembled and the connection points. It would help a lot.

Greg

[Sabre]

Hi Greg,

Thanks for responding. I have worked with it a bit and this is the best I can do. In the one pic you can see that the shaft is not square which to square I think I would need to bend the lower fuselage tubing which I not to excited about. Bending the upper tabs or putting a side load on the trim motor's lower mount tabs doesn't seem like a good choice as the amount seems excessive.

Thanks, Greg

[n85ae]

You only have a couple choices.

Pop a bolt in the upper attach and zip a reamer through the lower mounts
and then decide if the slop is excessive. If so then drill out the tabs to the size
that allows a shouldered bushing. If the slop isn't that bad use it as is.

Or cut and reweld one of the tabs.

Lacking welding facilities the shoulder bushing option would be an easy fix.

[Danzer1]

Reaming the lower holes should be the way to go - to elongate a little up on one tab bolt hole and down on the other - it shouldn't really take much, as a little movement on the bottom mount will create more side play on the top than you might think, it's a pretty long arm. Just make sure nothing binds or ends up "sloppy".

Greg

[Sabre]

Thanks for the input - pretty much what I had concluded as well. I agree it won't take much a the bottom mount to move it to the desire position; just worried about introducing a new problem trying to correct the other. Your input is much appreciated. Greg

[Danh]

I ran into the same problem, installed it with a slight bind, I think I will remove the lower bolt and elongate a little to help ease the bind

[Flybyjim]

Is this a super 7? If it is Have you emailed or called John at the factory about this mis- alignment, this should not be this way in any quality kit. I would not alter or bend anything until you have a discussion with John.

[jtpitkin06]

Have you positively identified the problem is a misalignment of the lower fuselage tabs? Try turning the trim motor assembly around and see if the offset reverses. If so then the hole in the trim motor is the fault.

Shy away from any fix that leaves you with an out-of-round hole in the fuselage tabs or the trim motor. This is, after all, the only connection of the stab leading edge.

I would feel comfortable reaming to a larger size and installing a bushing. The earlier models did use a bushing on the lower end. Subsequently deleted on later production as the motor assembly doesn't pivot enough to warrant a bushing. The reaming would only require a few thou for a thin wall bushing.

By all means, give McBean a call just to raise your comfort level.

John Pitkin
Greenville, Tx

[Sabre]

A follow-up to the conversation concerning miss-alignment with the trim motor assembly with respect to the lower fuselage mounting tabs for those who follow. After emailing with the factory elongating the holes is NOT a good option and in retrospect I should have investigated the problem more before I slightly elongated the holes in the mounting tabs in opposite directions. This did result in squaring the bolt to the fuselage but there might have been better approaches. And while statically this approach seems fine I really began to question long-term dynamic forces and the suitability of the above approach.
So to remedy the situation at the direction of the factory I’m going to fabricate mirror images of the tabs and bond and rivet them to the inside of the mounting tabs made from .063" 4130. This maximizes surface area and avoids the welds. .063" is the thickness of the AN960-10 washers installed and is the thickness of the tabs. To align the holes in the bonded pieces I plan to install the elevator trim assembly and bond washers to the outside surfaces of the mounting tabs first using the bolt to align the washers. Once the Hysol dries the washers will be guides for drilling the holes to the proper angle so the assembly will be square with the elevator.
Any thoughts or ideas to improve this process would be welcomed.
Thanks, Greg

[Danh]

Greg,
I haven't done anything with mine yet, I was just getting ready to remove the horizontal stabilizer to make it easier to work on the vertical stab. And was at that time look real close at it to see what kind of alignment I have. I recalled my original alignment looked a lot like yours but was able to tweet it into place without elongating any of the holes. But was worried about any binding on the trim actuator. I will check my out in the next few days

[Danh]

I removed my trim actuator and found by tweeting it into alignment I bent the rod end :(.
it looks like if I just use a thin nylon washer at both ends it will align up ok, when I first installed it I used a thick washer and nylon washers at each end. I will replace the rod end before reinstalling.

[Flybyjim]

When you called kitfox and talked to John what was his response to the misalignment? I have a kit on order and would like to know if this problem has been corrected. If your problem is in reference to the SS7 kit and it is now known as a problem in a major structure area I would like to think kitfox would have corrected the alignment. I'll keep checking in on this thread, would love to know ow many others had the same issue.

[Sabre]

Jim, my conversation with the factory was limited to email however, I do not think that it was is viewed as a problem (SS7). So far, pretty much everything requires tweaking of some kind to get the fit and finish desired (builder defined). This was just another one of those adjustments needed to the actuator rod end and now is perfectly centered after installing, bonding/riveting, and drilling the mirrored tabs in the actuator pivot. I suspect that the miss-alignment was acceptable as was the slightly elongated holes in the actuator pivot however, I was not happy with either.

[bushfly]

I just got my SS kit last month and my actuator doesnt align either. It looks exactly like Sabres pictures. I am finding this frustrating since it appears it is a known problem.

[Flybyjim]

I am to take delivery on an SS7 in a couple of months and I am becoming concerned about the improper fit to this fitting for the trim. In no way should one ever have to elongate a hole for proper fit. I have a Rans S-7 that I finished in 2011 and I had no problems with fit or finish with their plane. I believe I will send an email directly to John and find out why this has not been addressed and the corrections made if indeed there is a misfit for the alignment. If there is a known problem I would like to think John/Debra would address this. They seem like great folks to deal with, I have heard nothing but positive feed back from people I know that have the kit fox planes. If this is an isolated problem please feel free to chime in here and correct these concerns
Jim

[Esser]

My 2012 kit was fine

[rosslr]

Mine too - although it was a bit of an interesting tight exercise to fit all the washers in the scissors linkage at the top! I have just bought the trim indicator and about to fit it also - I think it might be best to order that at the start and fit it at the same time - I cant see any advantage to waiting 'till later (?).


cheers

ross

[Dorsal]

I had no issues (would definitely put the indicator on while building if able)

[Flybyjim]

Well, this sounds like the fit of the trim parts must be acceptable for most builders and there is some fitting to be done. I will be anxious to see how the fit is when I receive my kit, it will be the first thing I check with all the posts about the fit.

When I first started to fly ultralights in the 90's I always wanted to buy an Avid but life was not allowing the funds while raising a family of 3 girls along with my wife. As time goes by I have loved the flight of the tandem seating as so I went for the Rans S7, still love the plane. However things change and when I do have passengers I want the side by side and the Kitfox SS7 fits the mission I feel better than any other kit plane out there. I to was impressed with John and Debra's attention to their customers request and I was able to get some flight time with John in a great day for a test flight. 20mph winds with lots of gusts and the plane handled very well, I was very comfortable with the handling of this craft.
Jim

[Flybyjim]

The indicated is not with the kit? This is a separate purchase?

[rosslr]

that's correct Jim

r

[Flybyjim]

Is the indicator a dedicated piece from Kitfox or will a Ray Allen indicator work. Perhaps there is an accessory area on kit fox's site I need to visit and see what else is not with the kit?

[SkyPirate]

on the kitfox website..have you browsed the catalog?

[Dorsal]

You can see some pics on how others have made indicator adaptors in the photo section.

[bushfly]

Regarding the alignment of the actuator. The facatory sent this photo and description for the fix.

The assembly in the manual is for reference.. the number of washers is not
necessarily what will be used. That being said you do want at least one
washer.

You'll find that if you place a AN3 bolt through the holes in the fuselage
tabs then take a Crescent wrench over the tab you can bend both tabs
slightly and keep the alignment of the mounting holes. (see pic) The amount
needed will be very minor to have the top of the actuator line up.

We typically shift the actuator to one side and a thin plus a plastic
washer.

[Av8r3400]

Static ports are part of the pitot-static system that gives air pressure to the airspeed, altimeter and rate of climb instruments.

The "port" is the opening to get this static air pressure signal.


Good question. :)

[jtpitkin06]

What are static ports on an airplane?
http://watchfree.me/72/w.png

Here's a good text to learn about small aircraft. This book has been the standard for over 40 years. Available from the online book stores for about $13 or download it for free from the FAA, about 100 MB. It is the book I used for my Private Pilot in 1969 and now use with my student pilots. Updated by the FAA from an advisory circular to an official handbook.

Free...

https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/pilot_handbook/

Barnes and Noble hard copy...(recommended)
Pilot's Handbook of Aeronautical Knowledge: FAA-H-8083-25A (http://www.barnesandnoble.com/w/pilots-handbook-of-aeronautical-knowledge-federal-aviation-administration/1016050106?ean=9781560277507)



John Pitkin
Greenville, Texas

[Sabre]

Before I trim the vertical stabilizer trailing edge (fairing) I wanted to check were exactly to trim. It appears that trimming at the bottom of the rib is the spot but, ascetically trimming to the bottom of the tubing (fuselage) just above the tailwheel mounting plate (looks like it will make installing the tailwheel harder and might complicate the covering process?) might be better? I attached a pic with arrows, appreciate any input. Thanks.

[jrevens]

Sabre,

I trimmed mine to the upper arrow on your photo.

[Danh]

Same with my trim, the upper mark on the wood rib

[Dave S]

Sabre,

Here is a pre-covering photo of the area you are asking about (It is upside down compared to your photo) - The fairing was cut at what would be the upper option on your photo, and, the area forward of the bolt plate was filled in to make a smooth transition.

It's a trigear but the bolt plate is the same for the tailspring or tailskid.

Sincerely,

Dave S
KF7 Trigear
912ULS Warp Drive

[DesertFox4]

Sabre- I just trimmed my fairings to the upper arrow in your picture this afternoon. Mounted the rudder and they match up nicely and it looks great.

[jiott]

Yes definitely, the upper arrow.

[Sabre]

Thanks for the input and picture - very helpful. Greg

[bushfly]

I posted a question here: http://www.teamkitfox.com/Forums/showthread.php?t=5778 There was some good advice here on this thread so any input would be nice.

[Sabre]

I am getting ready to set the wings to the fuselage. The manual states leveling the fuselage from the underside of the fuselage using the lift strut carry-through tube and the bottom tube of the front bulk head. It appears that people also are using the fuselage carry-through tubes on top. Does it matter? Is the underside better as far as a reference for the fuselage datum? I also noted that for weight and balance the underside is used. Is there a obvious reason the underside is used that I'm missing? Thanks, Greg

[jiott]

I think most people use the top carry-through tubes, but it really doesn't matter because they are parallel with the bottom tubes. If you think about it, the top tubes really make more sense because when its flying the whole airplane hangs from these top tubes where the wings attach. The bottom surface is of no consequence. It really boils down to what is easiest to use and reference to.