Swift Landing Gear Page Three...

TORQUE KNEE BOLT/BUSH KIT...  (8599)
From: gi@globe-swift.net (George N2451B)
Hi Monty,
Christian and I are trying to figure out how the torque knee bolt/bush kit correctly goes together.  Do you have a detailed description? Regards, -- George

George,
Only 3 bolts from the bolt & bushing kit go in each torque knee. Compare the old ones. There are some bushings that go into the 2 links that make up the "scissors" (torque knee) Again, compare what was there. Did you find some steel assemblies? You kind of have to figure out how it will work correctly and install it accordingly. From memory, the right and left are different, when assembled, if the right side upper link is straight, the lower one will be angled. And if the left side upper is angled, the lower will be straight. Pull the Allen plug and metering valve assembly out of the outer cylinder. To do this, perhaps it's easiest to remove the 8 1/4" bolts and remove the entire landing gear. To pull the metering valve in place, you must cut a hole in the skin immediately above the plug. (about 1") With the metering valve removed you can put the strut tube in place as many times as you want easily to determine how the scissors (torque knee) goes. Don't forget the stop that goes on the upper link of the torque knee. Remember the strut will go to full extension in flight, or whenever the weight is off of it. I hope this is clear, sometimes it's easier to do something than explain it! -- Jim

TORQUE KNEE BOLT/BUSH KIT, PART TWO...  (8599)
From: "George N2451B" <gi@globe-swift.net>
Subject: RE: torque knee assembly
Hi Monty,
Thanks for the answer. The big problem is that when we disassembled the old one we found that it was put together completely wrong (or totally different). So there is no chance of looking how it was and just doing it reverse... We believe that this is the reason why it failed!

We believe we located the right bushings and cut the right steel tubing that was supplied with the kit but there is still a lot of play. That might go once we tighten everything but right now I am even not quite sure what to tighten and how much. The next problem is that my Swift (N2451B) has an Adel gear. So I am a little bit reluctant to just copying what we find there. Regards -- George

George,
I had assumed your old one that failed was aluminum. Is that not right? You have located some steel parts now, right? Are they new? Some of those ELI scissors require some grinding to provide clearance to avoid binding up as the strut nears the fully deflated position. I can't remember if I ever had any brand new ones, but I remember I had one I had to rework to avoid link-to-link contact before the strut was fully bottomed out. The steel scissors (torque knees) that I have had were probably all from the factory days, and had previously been reworked.

I'm not sure what you mean by a lot of play. I would call .010 a lot of play. (sorry if you're not used to thousandths of an inch measurements) If its even more than that, there is something not right. Where the two links of the torque knee join, there should be bushings with (I believe) a 5/16" ID. (inside diameter) Then a small steel bushing with an outside diameter of 5/16" and ID of 1/4" to provide freedom of movement and shear strength to the joint. Then a 1/4" bolt gets installed there of course. You should be able to tighten all 3 bolts in the torque knee and still have freedom of movement. You say you cut the tubing. That puzzles me. I have never found that necessary.

Maybe the contents of the bolt and bushing kit have changed over the years. I sure wish I could look directly at your problem. It's probably something simple that an experienced person would see right off. I don't know if this is any help, I can photograph one possibly, I'm not sure who around here has a disassembled ELI right now. I don't, I have the Adel gear on all the Swifts I'm involved with. -- Jim

WHAT IS REALLY THE INTENTION OF THE LIMITATION "DO NOT LOWER LANDING GEAR ABOVE 100 MPH"...  (10199)
Subj: Landing Gear Speed
From: Bob Runge ,ejectr@javanet.com>
Hi Jim:
Swifts are placarded "Do not lower landing gear above 100MPH."  Does that also mean you can't fly above 100 MPH with the gear out? Best regards....... Bob Runge

Bob:
No, I was told once that in certification, one gear comes out first and causes a yaw, the CAA (FAA) had (has?) a requirement that the aircraft only yaws so many degrees when one gear is down and one up. The Swift, at speeds over 100 mph exceeds those limits. Once the gear is extended, I don't see any requirement to limit the airspeed. Many people have seen Mark Holliday do his gear down loops in the GC-1A Swift. I have never asked Mark what he uses for a entry speed, but I have tried loops in my own GC-1A and it seems to me 140 mph ias was required. -- Jim

I LOVE THE SMELL OF 5606 IN THE MORNING... (112199)
From: Horst Brinker <brinker@arkansas.net>
First, The section of the hydraulic manual on servicing the tail strut states in step 3, " Continue filling till oil flows out the filler plug hole". Now assuming we followed steps 1 and 2, it seems to me that the strut is now completely filled with oil and very little air. I thought it a tad strange but followed the instructions only to have a shower of hydraulic fluid run down the strut for the next week until everything evened out. The strut works fine now and doesn't leak anymore. I've read through the blue book looking for an errata on the hydraulic manual and didn't find it. I'm pretty much ready to draw a line through that phrase in step 3 though. Any guidance from the wizards out there, Monty?

Second question is on the adel gear. My right strut leaks regardless of who rebuilds it. The leak is from the top part of the strut, and I'm now reasonably sure it's leaking between the trunnion and the brass sleeve. I'm not sure whether I have the "new o ring groove" cut into the sleeve or not. I used to be able to pump the 20 pounds of air into the strut to keep the leaking down, but last time I tried it, the air came back out through the brass sleeve retaining bolt. I'm wondering if it's safe to loosen or remove that bolt to put some kind of sealant on it to at least keep the air and the trickle of oil in the strut. If so, what's the best sealant to use? I'm worried about things going out of alignment if I loosen the bolt and I'm also worried that the wrong goop will glue the sleeve into the trunion making future service difficult. Thanks, Horst

Horst: I must confess I hadn't read the book on the tail strut for years. Years ago, Univair sold these struts for something like $12.00, so we never used to even bother changing "O" rings when they leaked. Note (in the hyd book) the sequence given, maybe you are confusing the filler plug and the bleeder plug. On the main gear leak, there are "O" rings on the inside, and the outside, of the brass sleeve in the strut, if the leakage is at the outer set of "O" rings the retainer bolt (set screw) may be where the air escapes. You should be able to remove this bolt and put some sealant and a soft washer on it. If the weight of the airplane is off the gear, that is if the airplane is on jacks, the set screw can be removed and the brass sleeve won't go anyplace. The sealant should be Aviation Permatex or something that won't react with MIL 5606. (NOT any RTV compounds) When the snap ring is removed next time, the sealant won't hold up the removal of the brass sleeve and associated parts.-- Jim

WHAT'S THAT ABOUT STEP THREE??? (12199)
From: Steve Wilson <SteveWlson@aol.com>
Horst wrote: >> I'm pretty much ready to draw a line through that phrase in step 3 though. Any guidance from the wizards out there<<

Yep. I don't know why step 3 is in the manual. Maybe just to see if anyone is reading it! If it worked that way with no leak, I bet you would have a mighty stiff strut. With the strut extended, fill through the "filler plug" (upper plug) until fluid runs out the "bleeder screw" (lower plug). That's it! Works great; lasts a long time! Cheers...Steve

HUH???  (12199)
From: Steve Roth <>
You know guys, I am really confused now. I have been continually told to "read the book", so when I did my tail shock strut I did as it said -- filled to the bleeder hole then replaced the bleeder plug and filled via the filler hole until full. I believed what it said to do (in step three) because I felt the shock strut was a typical "shock absorber", using the hydraulic fluid's ability to rush thru an orifice to provide the "shock absorbtion". Doesn't the Adel gear work the same way? Air has no function with "shock absorber" capability of the Adel gear, right? Am I missing something?

Steve,
Re: The tail strut. The book assumes the unit has been freshly assembled with all new parts.  Then, the procedure given is fine. In service, the volume of air and the volume of hydraulic fluid must be approximately the same. -- Jim

Steve,
Unfortunately a lot of manuals are not completely correct. What we are talking about here is the compressibility (or rather the non-compressibility characteristics of a liquid). If there is no air in the strut, the fluid has no "room" to transfer and will experience hydraulic lock. Fluid rushing through an orifice is only one part of the operation. A typical "shock absorber" depends on the compressibility (or displacement)of air in order to work. -- Steve Wilson

LANDING GEAR QUESTION...  (12199)
From: Steve Roth <>
You mention the "brass sleeve retention bolt". I don't recall such a "bolt". There is a "set screw" that locks the brass sleeve in place -- the brass sleeve would float inside the gear barrel without it. This set screw is installed on the opposite side of the barrel from the filler hole. Soft aluminum wahsers underneath it should seal it from leaking. At gear overhaul, it was very apparent that the set screws on my gear had been overtightened into the brass sleeve and dimpled it so the sleeve would not slide freely on the chrome strut. I leaked fluid from one of them because it could not be tightened enough to seal under the bolt head. I corrected all of that when I overhauled it with a friend. I can give you details, if you need them.  I envision the only place for a landing gear strut to leak is around the chrome strut itself. O-Rings should correct that. If it leaks anywhere else, then you have another problem not associated with the brass sleeve/O-Rings.  Steve Roth

Steve,
I have difficulty calling a hex head bolt a set screw - although that is what the book calls it.  Yes, the aluminum washer should keep it from leaking. The key word here being "should".  The Adel strut is designed for ambient air pressure to be in the small upper chamber, but with air valves installed, 100 psi or more can be packed into that small area, which can multiply several times in a hard landing. This in turn, can't hurt anything - except air leakage! -- Jim

EARLY LANDING GEAR QUESTION... (12499)
Subject: Re: 1A's
From: Peet King <peetking@earthlink.net>
On the light landing gear on 80518, there is a tapered pin that holds the lower fork and strut tube together. It is threaded on one end so it won't back out. It is drilled and takes a castilated nut. Later model gear has a regular bolt for this application. Where the bolt head would be, it is slightly domed. What do you call this pin?? -- Pete King

Pete;
Hmm.... I've had a couple of GC-1A's with that early Globe gear and they had regular bolts. At least, a regular slotted head, domed, screw headed bolt. What you are describing sounds like a clevis pin. I suspect you could drill it oversize, install a bushing and then install a 3/8" bolt. That type of bolt should be available from Swift Parts. -- Jim

OK GANG, WRITE THESE NUMBERS DOWN AND KEEP THEM HANDY... (010400)
From: "Thomas N. Veres" <airbum@hotmail.com>
Subject: Dimensions of Swift Landing gear.
Hi, My Name is Thom Veres and I am a new member of the Swift Club on Yahoo.Com . I was told that I could E-Mail You and possibly get the information that I need so that I can transport a Swift by trailer so I can get the Darn Thing Home. What I need is the dimensions of the main gear inside Right to inside Left and the C/L measurement main wheel to main wheel. The dimensions of C/L of the main axles to the C/L of the tail wheel axle. Also the Length of the plane with the Horizontal and Vertical Feathers Removed to the Front of the Propeller Hub. And Last of All the diminution of the aircraft width from the ends of the wing attach point to wing attach point. If you can please help me find this information it would be very helpful for preparation for my 700 mile trek to get her home this coming weekend. I will be more than grateful for your help. THANK YOU MUCH, Thom Veres

(Following reply from guest "Answer Man" Don Bartholomew <spectro@nanosecond.com>
Hi Tom,
Here are the dimensions you requested. Main gear inside Right to inside Left 105.5" The C/L measurement main wheel to main wheel. 117" The dimensions of C/L of the main axles to the C/L of the tail wheel axle. 160" Also the Length of the plane with the Horizontal and Vertical Feathers Removed to the Front of the Propeller Hub. 221" And Last of All the diminution of the aircraft width from the ends of the wing attach point to wing attach point. 127" For transporting a Swift, I: Remove the outer wing panels, and put a piece of angle iron on the center section wing attach points on one side to use as a foot. Bolt a 3' piece of angle to the wing attach point on the other side to attach tie straps to. Turn the plane knife edge on the trailer. Put a tail stand under the aft fuselage. Tie everything down.  I do it this was so I don't have to deal with oversize permits and restrictions and I feel it is more stable than carrying it on a 45 degree angle. There are a couple of pictures of my setup on Denis' GTS Homepage. Good Luck, Don

LANDING GEAR "WOBBLE"... (020100)
Subject: Re: N80572
From: Bill Doty <wdoty@seidata.com>
Jim,
I am installing the Cleveland wheels and brakes and notice some wobble in the "oleo" struts.. How much is allowable and how do you measure. Main wear seems to be in the top and bottom bushings. I probably have approx. 1/4" movement at the tire tread on 6" tires. Bill Doty

Bill,
Read AD note 51-11-04. It tells you the wear limits for the landing gear. While you are at it, read AD 46-06-01 for the adjustment of the linkage. If you don't have those AD notes, you should, and they are printed in a little booklet available from the Swift Association. Your IA must also have these AD notes, which he can print a copy. You can read AD notes here, if you have a Pentium 2 or 3 computer... http://www.fedworld.gov/pub/faa-cai/faa-cai.htm -- Jim

MORE ON THE LANDING GEAR WOBBLE AND BRAKE LINE ROUTING... (020100)
Subject: Re: Messanger:
To: Bill Doty <wdoty@seidata.com>
Jim,
Got your answer on wheel wobble, sounds like I am O.K. for now. However, the wobble I am talking about is side to side "like tow-in". Next problem is correct routing of the brake line from wheel cylinder to connection at wing. Joe (parts) told me 36" long on the brake line. The way it was routed 36" is to short. So probably was wrong. Can you explain proper route? -- Bill

Bill,
That ("wobble") movement is usually due to some wear in the scissors (torque links in the parts catalogue) 1/4" is not very much. There are 3 ea. 1/4" bolts that may be worn, as well as the bushings. 1/4" AN bolts mike about .246, a NAS bolt will mike about .248 and a close tolerence bolt .250. Use a slightly larger dia. bolt or replace bushings, available from Swift parts. Regarding the brake line routing... Do you have the stock gear doors for the Adel gear? It seems from memory the length of the hoses was 38". The hose gets routed between the gear and the gear door, that's why those "bulges" are in the Adel door. It is not easy to explain the routing, can you just look at another airplane? The hose comes off of a 1/4" AN fitting, over the gear, down, then aft, crossing behind the gear strut, then down to the brake. -- Jim

ADEL VS ELI - THERE IS A DIFFERENCE... (020100)
Subject: Re: BRAKE HOSE
To: Bill Doty <wdoty@seidata.com>
Jim,
I think I have E.L.I. gear. They are air over oil system. When the hose comes off of the fitting near the leading edge of wing: #1 which hole in the rib does it go thru? #2 Does it go over the pivot arm of the gear or between the gear and inside of rib ? It then goes down to a clamp around the main cylinder of gear and then on to the wheel cylinder. Was not attached to or near the gear door, which I think are P-51 original doors. I might have to send you a picture. They say a picture is worth a 1000 words. Bill

Bill,
I don't know why, but I thought you had the Adel gear. The ELI is definitely air/oil. It seems to me the hose goes over the gear after coming thru the big lightening hole in the rib, then inside of the gear and down... it gets clamped twice, once to the upper bracket on the forward side of the gear and once to the lower bracket on the aft side of the gear. WAIT! Original P-51 doors! Sorry to tell you, but there ain't no such animal! The so-called P-51 gear doors are a fairly new STC. (like in the last 20 years or so..) There ought to be installation instructions for those doors, including the hose routing in you aircraft paperwork. I guess you better send me a picture. -- Jim

Landing Gear Page Four