Cruisair Gear

N

nvracer

New member
I am rebuilding a set of main gear legs for my Cruisair. Does anyone know the correct kind of fluid to put in the gear legs & the quantity to install? I presume that you put the fluid in at the top of the gear leg.

Thanks,

Ray
 
Ray,Use 5606 Fluid same as brake fluid, the red stuff. Fill the strut to the bottom of the compression spring or higher. It will all work out!! Lynn N9818B
 
Thanks Lynn,

My gear is for a 14-13-2 & is different than 14-19 gear in that the taxi/compression spring sits on top of a spacer in the lower gear leg. There is also a spacer/damper that is attached to the top of the upper gear leg. The spring is between the 2 spacers. The bottom of the spring is about 12" up from the center of the axel. To fill the lower strut to the bottom of the spring would not do anything. There is a plug at the top of the upper gear leg and another one 8" down from the top of the upper gear leg. Maybe you fill the strut until fluid comes out of the lower plug. Then the question would be with the gear leg extended or loaded? What do you think?

Thanks,

Ray
 
We fill ours to the lower plug with the gear extended not loaded, safety wire 'er up, drop the jacks, and get back to flying. I've heard many opinions on what oil to use.....as long as it keeps it lubed and dampened, not sure it matters, but Miller's suggest that the red hydro fluid be replaced with 10 wt, I'm sure either will work fine.
 
Can anyone tell me if the Cruisair is set up with either toe-in or
toe-out? By the way, I'm new to the forum, trying to learn about these aircraft. Thanks, Joe Philips
 
Can anyone tell me if the Cruisair is set up with either toe-in or
toe-out? By the way, I'm new to the forum, trying to learn about these aircraft. Thanks, Joe Philips
Click to expand...

all t/w aircraft main gear should be set up either dead-straight or with a small amount of toe-in (of course, always defer to the factory maintainence manual). toe-out will result in any yaw (on the ground) being magnified and then you will really have your hands/feet full. :shock:

hope this helps!

P.S. the "quote" function doesn't seem to be working properly. anyone know why/what can be done about it?
 
That is an interesting response. I just bought a 14-19-2 and am finding it a handful to land (despite a couple hundred plus hours in similar models 20 years ago. I just attended the Columbia get-together and everyone I talked to indicated that toe-in was the deadly one. I went home and checked my plane and sure enough, there is considerable toe-in. Tomorrow I will jack it up and see if I can shim it out on the scissors where it connects to the lower gear strut. I got several suggestions of what to do next if that won't fix the problem, but I invite suggestions as to what to do next, and whether a bit of toe in is OK. I don't have a bit, I have what I consider a lot. When I put a 7 foot board on the side of the wheels, there was a 5 inch difference between the two ends. Actually, as I calculate the angle, it boils down to only 1.5 degrees on each wheel. contact me with your ideas petersch@exwire.com
 
Part of the reason I asked this question is that I have just finished a Piel Super Emeraude. It's a low wing with fixed conventional gear. The plans call for 1.3 degrees toe-out. Some people I talk to think that's correct, others disagree. I've yet to fly the airplane, so I don't know, but I would like NOT to be thinking about it on final!? I was wondering if anyone with a Cruisair had experience, either way. The Cruisair, like the Emeraude has a low center of gravity, wide gear, should be an easy taildragger to tame.
 
joe,

draw yourself a free-body diagram of the toe-in/toe-out situation.

btw, let's make sure we all agree on terms. toe-in is where the front of the wheel/tire is closer to the centerline of the a/c than the aft side of the tire. / \

1) toe-in: assume the gear is yawed to the left. the advancing wheel (rhs) will scrub since it's angle relative to the direction of travel is more and cause more drag than the retreating wheel (lhs) which will have less of an angle. this added drag on the rhs will tend to straighten out the gear. this is good! :D

2) toe-out: it will do just the opposite of what i've described above and will tend to exacerbate the yaw. this is not good! :cry:

i realize that this is one of those "down-wind turn" controversies, but if you examine the geometry of what's going on, i think you'll have to agree that toe-in (as i've described it) will be more stable than toe-out.

hope this helps! :D

blue skies,
vic & N522A
 
that on roll out, as the aircraft is yawed to the left, it's weight has been shifted to the right, on to the right gear which is pointed to the right, or straight(er). Therefore, any ground looping turn that is started on the outside tire is less intense in force. Also any induced occillations which also induce weight shifts from gear to gear are dampened out by this arrangement where as if there was toe-in, it would intensify the turns. The point being that aircraft turns shift weight to the outside tire, the tire if toe-out lessens any turning tendancy of this tire. I'm not saying I know for sure. It's certainly debateable. Some pilots believe that during the initial touchdown that the speed of the aircraft and the adequate directional control from adverse aileron yaw and rudder control negate any toe-in/toe-out wheel geometry. That the wheel geometry is only important as the tail begins to settle, loose effectiveness. It is interesting.
 
This is funny :lol:
When I got my first taildragger homebuilt, there was a little toe out. I ask old timers why and they told me: adjust in toe-in and be ready for a hell ride on landing. Especially when bringing the tail down after wheel landing. Not much control any more with the rudder and not yet with the tail wheel. Weight goes on outboard wheel if you start turning and the wheel pointing where you're turning.
Then, here I am with the Cruisair. A friend Cherokee pilot came to me: Alain, your airplane is f...cked up. it has toe out. The hangar neighbour told him the same I've been told years ago. Toe in align you for a ground loop. Note that when tail down, it will show more toe out then when aicraft rolling level just before take off. this is due to the top of the wheels being closer then the bottom. when level it quite parallel on the asphalt. When tail down, it goes toe out a bit. make yourself a small replica with radio control spring axle you'll see. :D

Alain.
 
Does anyone ski. Beginning skiers learn to do the wedge or snowplow where they have their skis so the tips are close together and the tails are far apart. When you put weight on one of the skis, that ski will carry the skier the way it is pointed. Similarly if you imagine one of the two tires with the toe in condition. Let us imagine the right tire. With toe in, it points to the left. If on landing you make a slight turn to the left, centrifugal force will put more weight on the right tire. Since the weighted tire will have more of a determinatation of the direction of travel (like the skier) the slight turn to the left will then become a big turn to the left. Toe out on the other hand would negate the turning tendancy. (like wind dihedral fixes banking). I have flown tail dragger Bellancas for hundreds of hours with no problem. I just bought one that has "toe-in" and I am making groundloops on about a third of my landings (would be higher if I didn't have an instructor next to me most of the time. I took a CFI with 2600 hours of taildragger time (and tons of total time) up with me the other day and he experienced the first groundloop of his life. You can't convince me that toe-in is desireable. I guess my next question is "How bad is toe-out?" I jacked my plane today (no more flying till it's fixed) and there is a lot of need for shims and I think the toe in can be corrected. Will give you all updates, but in the meantime, please give me all the imput I can get.
 
Peter, could the upper struts could be on the wrong side? left on the right and right on the left?
Is this possible on a cruisair guys?
 
Upper struts on the wrong side?/ I hadn't thought of that and if shimming doesn't do the trick, that might be my next trick. The last thing I want to do is have to change the angle of the two ears on the bottom strut where the scissor attaches (which will certainly rotate the wheel more toward toe-out but it seems like a radical maneuver. The plane assumedly left the factory without this problem and when someone did a restoration, it ended up with the problem. Thanks for the idea! Keep those cards and letters coming! Peter
 
maybe the whole link assenbly too, something might have been inverted somewhere. Gear to spar fitting maybe. Or maybe it is just not possible and is made fool proof, then, you have a problem! :?
 
Alain1 said:
...make yourself a small replica with radio control spring axle you'll see. :D

Alain.
Click to expand...

i have built hundreds of r/c and free-flight models over the years, most of them tailwheel. my experience has been that toe-in is good, toe-out is not good. whether model or full-size, the geometry and dynamics are the same (just like the wing).

but, do what you and your mechanic think is best and let us know how it turns out.

blue skies,
vic & N522A
 
Peter, You know what!
I will go and look at the airplane tomorrow. It is the most docile taildragger I flew. I have abou t1200 hrs in about a dozen different Taildraggers. I will measure and if it is toe-in, maybe some confusion here, I will let you know.
I cannot argue with a guy like Vic. The guy knows is stuff. And I am man enough to admit when I'm wrong.
But I remember the guys telling me to leave it like it was because I would put myself onthe line for a ride... :oops: Maybe it was toe-in.
I will measure several taildraggers around mine and it will bring you an answer. Vic is probably right.

A.
 
Not only do I have toe in, but I have looseness in the gear- it isn't ridiculous, but more than I would think it should be (had to jack it to find out) I'm hoping that by properly shimming the scissors, I can take out the loosesness and fix the toe in as well (it's about 1.5 degrees but looks like more to my eye.) I am afraid too that my brass bushings may be worn also (the ones inside the upper strut) . Are they available from the factory or do I have the local machine shop make them?
 
Peter,
Went to the airfield this moring before coming to work. It is Toe In.
I was completely in the "field" :roll:

Vic thanks for raising the flag. :wink:

As for gear parts??? not enough experience buying parts yet!
Maybe some other member of the club can answer you.

Alain
 
How did you determine "toe in" on your craft? On mine, I took long 2x4's and placed them against the wheel and using a plumb bob and a helper dropped the boards to the ground and drew chalk lines. Two center lines were created with string and plumb bobs and chalk. One from the tail wheel up the longeron on the bottom of the fuselage, and another using the tip of the spinner (slight difference and I don't know if the engine is or isn't canted a couple of degrees. Anyhow, it appeared prior to the chalk lines that the left gear was toed in and the right was straight, but my chalk lines betrayed just the opposite=the right is toed in and the left is straight. Then again there is the jiggle factor which could also be contributing to the unlandability of my plane. Merci, Alain
 
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