LANDING GEAR - GENERAL

LANDING GEAR ELECTRICAL...(090202)
Subj: landing gear
From: Ed Clegg <edwclg@hotmail.com>
Hi Monty,
I have a few questions for you. A problem has come up with the gear and I think it might be the swich behind the inst.panel. While flying the other day I placed the gear lever down and nothing happened for a couple of seconds. Then the amber lite came on dim and finally the gear came down normally. So indications were.
1. gear lever down
2. nothing for a couple of seconds
3. amber lite dim with slight pump sound.(lasted a second or two)
4. aber lite bright, pump sounding normal and gear extened normally.
Ok, when flaps are selected,up or down, pump and light operate normally. (no delay and proper speed). On the grd in the hanger not on jacks yet. I removed both wires from the in side of the L.G.relay. When I pull out on the sissors releasing the micro swich I get an audible click of the sol'd and a dim red light and a bright throttle warning lite. I would have expected a bright red gear light. Also there is good continuity across the sol'd. When I connect either of the two previously disconnected wires and pull out on the sissors the motor fairly groans at first and after a couple of seconds comes on normally. I am going to pull the swich behind the panal and see if that is the cuprit. What do you think? Before checking all this stuff I was under the assumption that the flaps activated the motor through the relay. But that is wrong. How is the pump activated by the flap swich and where physically are the wires that run the motor? Also, these two wires on the in side of the relay I don't understand. The scmatic(SP) shows one from the 30 amp bkr and logic tells me I only need one to activate the pump. Either one will power the motor.??? I am heading over the hanger now to get it on jacks. Looking foward to your wisdom. Thanks Ed Clegg 3791K

Ed
It does sound like a poor contact in the circuit for the relay -- it may well be that switch behind the instrument panel. Once the relay got activated, the motor ran normally. The flaps do not operate thru that relay, not the best design perhaps but it has worked pretty well for over 50 years now. The way you describe your motor "groaning" perhaps it needs some attention, like new brushes or just cleaning the commutator. I forget, but it seems to me 91K has a modified Honda starter motor. Remove the motor and disassemble it and check the brushes. If they appear worn new brushes can be obtained from a Honda Motorcycle dealer. The wiring diagram for the flaps is on page 34 of the Swift Operating Handbook. As you see, one diagram is worth a thousand words when it comes to describing the flap operation! The relay gets its power thru the 30 amp breaker and needs that to operate. Also, see the "Monty the Answer Man" archive on the Swift site. Pay particular attention to Ron Williamsons answers. Also, maybe he will read this note and help out! -- Jim

LANDING GEAR ELECTRICAL PART TWO...(090202)
Subj: Re: landing gear
From: Ed Clegg <edwclg@hotmail.com>
Hi Again Monty,
I have looked at the flap diagram but still can not figure where the flap wiring physically connects the pump. Also do not understand why there are 2 wires going to the in(hot) side of the relay. I guess I'm missing something. I will work on this tomorrow and let you know the results.

Ed
Sorry I was not more clear. Get your book out. Look on pg. 32. Wire #34 is the main power going to the relay. The other wire is #104 from the selector switch behind the instrument panel, which changes to wire #24 at a junction block in the "J" box on the firewall. Wire #24 is the small wire which goes to the small post on the relay. When you select "up" the signal gets to the relay thru wires 104 & 24. A relay, of course, is an electrically actuated switch to eliminate arcing. When it "sucks in" the power gets to the motor thru wire #34. The flaps are even simpler. Wire #35 bypasses the relay by being on the downstream terminal and power runs from there directly to the motor. -- Jim

RON WILLIAMSON ADDS HIS INSIGHT ON ED'S LANDING GEAR DEAL...(090202)
Hi Ed/Monty,
Ed, the red gear light is supposed to be dim. Look closely at the book and you'll see there is a resistor in series with the bulb to reduce the voltage. Since the red light is on just about all the time the airplane is powered (unless you just like to taxi around the ramp), the resistor keeps the bulb life long and, more importantly, doesn't blind you during night operations. The gear warning light comes directly from the up selector switch and runs through the throttle switch without a resistor. It's supposed to be BRIGHT to get your attention, night or day. So, don't be concerned about the dim indication when gear is "up." As I've said before, in '40K, that indicator is labeled "unsafe" because it actually comes on any time the gear is off the down stop. Most of the time it is UP, but there's no guarantee. But, I digress.

If the hydraulic pump runs normally with the flaps, then I'd say the brushes are ok and the pump is good. As Monty correctly pointed out, the flap circuit directly switches the motor current and doesn't use the solenoid. That's why the flaps and gear can have different performance. I've always been amazed that those microswitches can survive while switching the huge current that the pump motor draws. But, 57 years of successful operation can't be ignored. The pump doesn't get a lot of use, so brushes should last a long time. If the shaft seal is bad, hydraulic fluid can wick up and get inside the motor. I've seen them get pretty goobered up and the brushes get glazed or gummed up so they won't make good contact. It's worth looking at anyway, but I don't think you'll find much there. If the brushes are gummy, Stoddard solvent will free things up, or you can use a simple contact cleaner spray available at Radio Shack. Or, simply replace the brushes as a preventive maintenance item. Last I heard they were around $12 from Honda. A bargain.

The amber light is connected directly to the pump motor and gets the same voltage. If the amber light is dim, that means the pump isn't getting full voltage. My analysis would be that the gear relay (contactor) points are worn or it's not pulling in solidly to make a good connection. The original relays were light duty, matched to the 25 amp motors that originally came with the Swift. Most of them were simple open frame design with a little plastic cover and not sealed up very well at all. Corrosion on the contacts and the usual dirt and grime that collects in the engine compartment are enough to reduce the contact pressure so they have high resistance. And, with the big Honda motorcycle starter conversion, the pump motor can draw as much as 50 or 60 amps when it starts up. The little relay contacts can get pretty beat up when switching that much current. In short, I'd look at the relay. You can pop the cover off if it's an original and hose it out with some Stoddard solvent, then look at the contacts. If it's gummy, then that may be enough to fix the problem. (you can operate the motor by taking a clip lead jumper and shorting between the +12 v power terminal and the coil terminal. The relay has 4 posts. Posts are: +12 power from the pump circuit breaker, +12v coil current from the gear selector switch, ground for the relay coil current, and +12v switched power output to the pump motor. The coil terminals are the small #6 or #8 posts and the big ones are for the motor current. It's easy to see which of the coil posts goes to the ground, as there's usually a short jumper that uses one of the the mounting screws as a ground. Just jump between the passenger side big terminal and the small coil terminal and the contact should operate snappy if it's ok. You'll get a little sparking because of the coil inductance, but it won't hurt anything.

The motor will simply run and the regulator valve will allow the fluid to bypass without operating anything. If the main contacts are fried, then the motor will run slowly as you observed before. If it's an original, I don't know of a factory replacement. Mostly the replacement that's popular is a White Rodgers (looks like a starter solenoid in the Aircraft Spruce Catalog). I'll have to go back and remind myself of the part number, but it's common and the part is also available from Grainger. About $25 or so.I'd be interested to hear what you find. -- Ron.

LANDING GEAR SUCCESS!!! HERE IS WHAT ED DID...(090202)
Subj: landing gear
From: Ed Clegg <edwclg@hotmail.com>
Hi Monty/Ron,
Here is what I did. I pulled the LG swich and jumped it. Still had problem. Replaced sw anyway due to slop in it. Had to be relay. Replaced that and all works well. But back to original questios. On the old relay there were 6 wires going to it,
1. control

2. grd.
3. pwr from 30 amp brkr
4. motor
5. amber lite/pwr for flap. This one I thought was only the amber lite. Therefor my confusion as to where the pwr from the flap got to the pump.
6. A hot wire to the in side of the relay. This one was hot anytime the master was on. It was an old cloth wire looking very much original.

When I e-mailed you Monty I had not been able to trace it. Well this wire is /was connected to the output side of the master swich running directly to the relay with no protection at all. This I do not under stand. If the motor circut shorted out anywhere along it's path the results.........well you know. I pulled it out and the system works fine. Of course the gear retracted a little faster with it connected due to the lack of voltage drop at the relay. At the in side of the relay I am losing about a half volt with that line disconnected. I was wondering if any other swift out there has the same setup.????What do you all think of this? Thanks for your support. Ed

Ed
It sounds like sombody had a problem with the circuit breaker popping so they but in a jumper wire. That would make the motor run without popping the c/b but of course the circuit would be completely unprotected! You may now run into a problem with the c/b popping because it may be a little weak. Its over 50 years old probably and it may open at something less than its rated 30 amps. I would suggest getting a new 30 amp c/b. The Honda motor might even require a little bigger c/b, at start up it may draw 40 amps or more. If the system pressure is set at 425 psi the amperage draw of the motor should not exceed 30 amps no matter what motor is installed for continuous running but the start up draw might be higher. -- Jim

TO TOE OUT OR NOT TO TOE OUT...(090402)
Subj: Wheel Alignment
From: Bud England <dalswift1@aol.com>
I was looking for the procedure to check/fix wheel (gear) alignment. Can't find it but know I've seen it. Where? Bud

Bud
I have not seen that in print. I think the Swift wheels were supposed to aim straight ahead. An easy way to check that is to get a pipe that will fit inside the axles. Charlie Hoover, who has played around with alignment tells me that if the wheels are toed in slightly, a Swift handles squirrely, and if they are toed out slightly, it is an easier handling airplane. This can be adjusted with washers at the scissors. I welcome further comment. I have not done much to ever change the alignment, but I had one Swift where one wheel was toed out considerably due to gearbox misalignment. It handled Ok as far as I was concerned and I just never worried about it.

-- Jim
PS... I talked with Mark Holliday & Charlie Hoover this morning, the general consensus seems to be that the wheels should be aligned straight ahead. Mark told of a Pitts that had one axle toed out and it was impossible to keep it straight on landing. I was told at one time that the Buckaroo had the wheels toed out slightly and this made it more docile than a Swift. Maybe you could write Charlie and ask if that's true.

T'IS LANDING GEAR CIRCUIT SEASON...(OCT 02)
Subj: Gear Woes
From: Richard Aaron <richard.aaron@us.army.mil>
Dear Jim,
I see from the last Newsletter that it's landing gear circuit season. After a long hot summer during which I didn't do much flying for various reasons, I was anxiously looking forward to the fall to make up for lost time. Alas, I've been smitten by the landing gear devil. My problem is with the micro-switch/indicator light circuit; the 5 amp breaker pops every 2nd or 3rd cycle going up or down. I've read all the manuals, archives, past newsletters, etc. and have eliminated mechanical causes, changed the solenoid, gear switch and have substituted another circuit breaker without solving the problem. On one or two occasions, there was no reaction at all when selecting gear down, but the circuit breaker was not popped and there was no red (or amber) light. Cycling the flaps did lock the gear down though. It would seem that the problem is either a micro-switch or wiring (what else is left?). ID-ing many of the wires is difficult. Any tricks or shortcuts for finding the fault or is brain surgery by e-mail impossible? Frustrated, Dick

Dick
Before I start, on the schematic in the "Operators Handbook and Maintenance Manual" there are the following discrepancies...... On the LG position selector switch on the instrument panel - up should be down and down should be up. Wire #19 and #63 are really the same. It goes to the center of the down limit switch Wire #38 is really #28 I think Bud England asked me about that in the Chat, but I couldn't answer off hand. I think the thing to do next is to go to the "J" box on the firewall and separate the connections and clean them with contact cleaner. (the Cannon plug comes off under the panel) Clean all the connections to the gear relay. If I follow you, the flap circuit works Ok, but the gear circuit is where the problem lies. It sounds like you have an intermittently open circuit. -- Jim

T'IS LANDING GEAR CIRCUIT SEASON PART DEUX...(OCT 02)
Subj: RE: Gear Woes
From: Richard Aaron <richard.aaron@us.army.mil>
Jim,
Thanks for your reply. Yes, it's the gear circuit, the flaps are working fine. I'll try cleaning the connections as you suggested and also the ones on the terminal block on the forward lower bulkhead and micro-switch connections; they deserve it after 54 years. Could this account for the 5 amp circuit breaker popping though? I haven't found any visible evidence of a short or heard any arcing and the micro-switches all work freely and "click". Have you ever run across a case where one went bad internally? In my case the wire numbers are moot as any markers are long gone. On the positive side, crawling under the panel and out again is lot's of fun! -- Dick

That c/b popping does have me puzzled. That doesn't fit with an open circuit. I might think you have a bad c/b, but didn't you tell me you had changed c/b's? Perhaps moisture in a microswich..........? Maybe some of the good minds that read Denis' Newsletter will read this and respond. -- Jim
PS Denis is at Westover having a good time, so he probably won't get a Newsletter out until sometime next week. (Editor says... This is true!)

T'IS LANDING GEAR CIRCUIT SEASON. SWIFTERS REPLY... (OCT 02)
Dick Aaron emailed last update about his circuit breaker problems. We got some replies to share with you. First I'll reprint Dick's original email to refresh your memory, then the replies...

From: Jim Thomason <mountville@aol.com>
Hi, Just a thought. The original wires to the gear lights have shielding on them. This could be shorting out, every now and then, on the wire inside . One of my customers swift had new light assemblies installed in the panel. The wires were "butt spliced" with the crimp connectors. After a few years the outer shielding on the old wire (which had been pushed back to get to the inner wire) slid up to the crimp and one stran went inside the crimp and shorted. This would pop the circuit breaker whenever the vibration (rough landing) was just right. Took a while to find. Hope this helps. -- Jim Thomason

From: Larry Owen <Larry.Owen@Tenethealth.com>
A few years ago I had a somewhat similar problem with the gear c/b It turned out to be the carbon brushes on the Hyd pump needed replacing. Flaps worked fine, (pump was cool, low number of amps to bring up flaps) but problems with the gear (pump had now warmed up and number of amps to pump the gear is higher) Sometimes the brushes where square-on and worked fine, other times (being worn) they were misaligned and popped the c/b. Cleaning the pump motor was no fun and finding the correct brushes was a chore but it sure fixed the problem. Larry Owen N78287 El Paso, Texas 915-577-6832

From: "Dooley, Dave" <ddooley@ball.com>
For Richard, I had the same problem with my Swift and it was discovered that the wire wound resistor for the gear indicator lights was shorting out to ground. Once I insulated that, never had a problem since. Dave Dooley N78325

From: Brian Silcox <briansilcox@harbornet.com>
Denis,
Just my two cents on the gear indicator circuit... I had this problem and discovered the microswitch was gummy, and was causing high resistance, which tripped the indicator breaker. Contact cleaner solved the problem once and for all. -- Brian

DICK SAYS THANKS!!! (OCT 02)
From: Richard Aaron <richard.aaron@us.army.mil>
Subject: Landing Gear Woes
Dennis,
I'd like to take advantage of the Newletter to thank everyone who took the time to respond to my call for help with my gear circuit. Everything's working fine now and I've discovered that electricity is a wonderful but mysterious thing. To summarize, I had changed the gear relay and panel switch to no avail. This past week I received new gear microswitches in the mail and changed those. While removing one of the old ones, the plunger broke off (hmmmm). I also found frayed wires going into the solderless terminal that connects to the 30 amp hydraulic motor circuit breaker. I'm planning to make and epoxy a button onto this breaker as it's very difficult to re-set because of it's recessed design. Mysteriously, while chasing down a suggestion about possible shorting of the outer shield on the indicator light wires I found that the one for the red light wasn't connected to ground (but the light was working anyway). I thought that it must be touching one of the other shields in the bundle to complete the circuit but I couldn't find anyplace that they were grounded either! In any case, while I was at it I re-wired the lights as described in the Maintenance Manual to give a separate indication for each gear individually. I found a cordless Dremel tool with a wire brush very useful for cleaning up solderless terminals and connections (go lightly). Re-wiring is on my list of things to do. I might add that I solder "solderless" terminals whenever possible. Regards, Dick N2405B

LANDING GEAR WON'T GO UP...(NOV 02)
From: Todd Warnock <tcwinmia@aol.com
Hi Jim, I am having trouble getting my gear up just after take off. I am climbing at 75 MPH and it just doesn't want to go all the way up. The motor appears to be working fine and I have full fluid. Is there a bubble? Also, I notice that I have to add fluid after several gear and flap cycles. I don' t see any leaks. What should I look for? Thanks, Todd

Todd
First of all, what motor do you have turning the hydraulic pump? Your hydraulic pressure is probably too low, but you can't raise it above 425 psi with the stock or any small pump motor. You need a heavy duty pump motor first of all, then you have to be sure your pressure is at least 425 psi and preferably 450 to 500 psi. Merlyn makes the only STCed motor, but there have been many others adapted, notably a Honda motorcycle starter motor. Carl Weddle adapted a 20 hp Mercury outboard starter motor which worked well. Joe Zito also adapted several types of 12 V DC motors. To read the hydraulic pressure a "T" can be put in the gear up line near the hydraulic package. Then raise the gear on jacks and note the reading. To raise the pressure the adjusting screw on the back of the package is screwed in. There is a check nut that must be cracked loose first. Do NOT raise the pressure over 500 psi, if you do there is a chance of shearing the Woodruff keys in the gear actuators. If you can't do this yourself, go to a knowledgeable shop or go up the Athens, TN and have the experts do it. If you are adding fluid it's got to be leaking somewhere. Many times the lines wear thru where they come thru the micarta block at the firewall. The downlock or gear actuator might be leaking too. When the gear stops going up a little negative "G" usually puts them in the wells, but you don't want to do that routinely. If the fluid level is low the gear won't come up either. Do you have the so-called P-51 gear doors? You need a big gear motor and a little more pressure with them. Once you get everything set right the gear will work very reliably. -- Jim

ONE HUNG LOW...(DEC 02)
Subj: A drooping Right gear
From: Pat Waters <gpwaters@aol.com
I have read over all your answers, but do not find this problem addressed. My right gear will only half retract. On jacks, I am able to move it up freely; however, it shoots oil out of the resivoir. It seemed to work and then it quit. Is there a simple solution? If you have time, I'd love to understand. Thank you, gpwaters

Pat
If your gear does not go all the way up there is probably not enough hydraulic pressure. If you force the gear up by hand or crank it down with the emergency system it is quite normal to shoot fluid out the vent. If the gear goes up and then falls out in flight it may not be rigged right and the emergency crankdown cable may be too tight. The linkage has to go over center and the uplock is actually gravity. If you raise the hydraulic pressure to above 425 psi and the motor stalls out you need to overhaul the motor or get a better one. Maybe your problem is as simple as low hydraulic fluid quantity. In South Carolina, have Jim Thomason take a look at it <Mountville@aol.com> Jim

Texas Swifter Steve Wilson adds...
Pat... I am assuming you are working with the airplane on jacks, and when you select the gear "up" the left main gear retracts completely, while the right starts to retract and stops before reaching the wheelwell... If this is true, and it worked at one time without any changes by you or someone else, then the right "up" limit switch is stuck closed. Once the left gear has fully retracted and closed the left "up" limit switch, the right "up" limit switch is telling the retract system, the right gear is also retracted (which you know it hasn't). Sound confusing? Try a little WD-40 working the plunger in and out a few times on the right micro-switch and see if things improve... Steve W

SUCCESS!!! (DEC 02)
From: Pat Waters <gpwaters@aol.com>
Subject: Re: A drooping Right gear
You have made my day. It was stuck and is now working well. Thank you and happy Thanksgiving. -- Pat

On to landing gear page SIX