I wonder if your gear alignment is a little off now with the taller bushweels, since they would lift up the nose a bit that would tend to give them a bit more toe out when the tail is on the ground.
I've got a 180 and CS in mine and as soon as I open the tap there's more than enough rudder authority to put the plane in the weeds on either side of the runway.
Does it wander off to the left as you start moving, or is it still wanting to go to the left even after the tail is coming off the ground?
Check your rudder peddals and rudder alignment. You are probably not getting full right rudder travel. Had that problem in '78' with down wind take offs and that was the fix.
More horse power on the same airframe (any single engine airframe) requires more right rudder on takeoff. As manufacturers started increasing horsepower they usually either cant the vertical stab or cant the engine, or both to counter the need for more rudder, which is relatively simple for the airframe manufacturer to do in production. However, this cant angle hurts cruise. Beech started canting the stabilizers as HP increased, and then when they went from the 470 to the 520 they canted the engine as well. But there are STC's available to install a 520 in place of the 470, in the straight mount bed. So, these STC'd aircraft see a significant increase in cruise, but also require alot of right rudder on takeoff.
I'm not aware of any legal alteration that you could do to correct this problem.
If your 180 HP conversion uses a dinafocal mount, you could cant the engine with spacer washers under both left side Lord mounts, canting the front of the engine to the right, but it will not line up perfectly with the cowl. This ain't legal either.
It's also pssible that VG's on the vertical would give a little more rudder authority at takeoff speeds.
wingnut wrote:...It's also pssible that VG's on the vertical would give a little more rudder authority at takeoff speeds.
I don't know of any VG kits that do this legally. Isn't it a simpler matter to just use a little right brake during the take off roll? My standard 170B even needs that occasionally.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
Heard all that more hp not enough tail feathers stuff way back then also. Does not apply in this case. Properly rigged they have been handling fine for over thirty years. Adjust the rudder cables with the turn buckles at the rudder until the rudder is lined up with the verticle and the rudder peddals are even. It goes without saying that the tires should be properly rigged also for best ground handling. Toe in/out, camber, and lined up with the rest of the plane.
I agree with Roesbery….and also George. I have a B with a 180 Lyc. and 80†CS prop also a Sportsman’s STOL and it is no sweat to take-off on wheels, skis or floats. I have always found enough rudder authority even with a left cross-wind. Hold the yoke back until you get a little speed and the rudder will work fine. If you are in the deep powder you probably want full forward yoke but then you probably don’t care if you fly a curvilinear takeoff. If you are on skis you have probably laid down tracks and have landed in them so you are in the “chute†so to speak.
Our rudders are fricken huge!!! I can't imagine running out of rudder authority especially with a little more wind on them from a 180! I think you are having some other problem as suggested before. My opinion.
David
Chris Christensen wrote:Has anyone out there ever had any problem with running out of right rudder during take off with one of the 180 hp / CS prop conversions.
I have had the problem of my plane wanting to wander over to the left occasionaly when taking off on wet grass with my "bald" 26" BushWheels.
...
Chris,
I've never performed a take-off in a 180 hp 170, so the existing rudder authority and maybe an occasional tap on the brake early in the roll has been adequate for me. The big thing is to make corrections early; the longer it wanders off, the harder it is to get back. After you get rolling and full rudder isn't causing a correction, maybe some left aileron (adverse yaw) and/or a light tap on the brake would help, same as if a cross wind from that direction was the cause of the problem.
Miles
Miles
“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
Well, first I want to say thanks for all the replys.
I may have found a clue in one of the links from Wingnut.
Down the list, just so ya know.
Jr. CubBuilder: The gear alignment is all but perfect. I have been fortunate enough to be allowed to be involved with all aspects of my last couple years of re-build. The wheels ran straight with no swivel in the alum. grease plates at all. I spent several hundred dollars buying ALL the possible shims that could be needed ahead of time. Hey Jr. what you doin sneakin in over here? Wanabe.
Wingnut & Gahorn: Have already thought about the possiblity that VGs might be at least a partial solution, specailly since they seem to be good enough to qualify for STC status on planes with a larger population. As a matter of fact I have actually managed to negotiate a verbal agreement on a 337 process between Micro VGs, Harry Delicker, and his long time acquaitance in the Fresno FSDO. Now I just need to get them on while they are still alive.
Roesbery: regarding Rudder Cables. They have been adjusted to the max. Had only 1/32 gap between the full right rudder and the right elevatror.
Dacker: "Our rudders are HUGE" Well if our rudders are so huge, why were they enlarged to the square version for the early 172s. Also why did they not stick to the "huge" round rudder for the 180 ?!?
Wingnut redux: The clue I mentioned was in the llinked article that wingnut posted. The clue has to do with the experiment of holding the prop in your hands and then lifting it from the elbows and see what a bigger bite ya now get on the right side. (if I read that correclty) NOW, I do have the longer wheels forward 180 gear with 26" Alaska Bush Weels on it. It DOES stand a bit taller. Actually it stands a bit taller at the top of the front wing root than my friens 180. It just could be that the taller stance. with more right prop bite, might be part of the problem.
Just so ya know, I have flown 170s on and off since the mid 50s. I have even flown a different 180hp 170 that was first put together by Trevor Hoy of Aviaon Research. Never had the same type of problem, but then, it was a used engine with the small, (canoe paddle) short prop, smaller stock 600 tires, and always on pavement.
I also flew this same airplane, that I know have, for a couple years out of MCCall Idaho with the previous owner. We covered bout half of the back country strips and never had the same problem. again with a tired old engine, short prop, and smalller (ribbed) tires.
Miles: I have been known to apply a bit of right brake on occasion, but it is not my preferred option. Several of the strips I use are really not wide enough or long enough for such a luxury. My friends strip up on the Klamath river only has a couple of feet on each side of the tires. You start on what is called the diving platform at the top. You have to use a peripheral view out one side to approximate runway alignment along with a spot off across the river. The runway then drops of at 14% so You can not see the actual runway when you first roll of the edge. The slope plus the downhill acceleration rate does not make the brakes a comfortable option. Ya only get about 600-800 feet to be off the ground, level out over the dip in the middle, and start to clear the 100'+ trees on the other end.
Thanks again to all Chris
53-170-B+
It is better to be late in this world, than early in the next !
Chris Christensen wrote:Actually it stands a bit taller at the top of the front wing root than my friens 180. It just could be that the taller stance. with more right prop bite, might be part of the problem.
Chris
AhHa! Slap one of those big tailwheels from XP mods on there with an L19 tailspring, and then air down the BWs to 2psi
I have flown 170's with both of the styles of 180 gear and 31" bushwheels with no adverse effects like you are describing. The one with the wheels fwd has a 180hp and a 3 blade Hartzell on it. The wheels aft one has the 210Hp with the 82" McCauley. One thing I have found though is you have to be good and straight with the runway before you start your take off roll or you will have to tap your brake a little to straighten it out but that was the case even with the stock motor. Before this plane I did a lot of Super Cub flying and was used to much better rudder authority with them. With Supercubs you can easily open the throttle for takeoff once you are 90 degrees to the runway and finsh your turn with just rudder while you are building speed. Some even do that when they are 180 degrees from there departure heading. That gets pretty radical though cause you are really side loading that gear as it comes around. Have you checked to make sure your brake caliper is not dragging just slightly?
Shawn
You say you have full rudder travel. Is that with someone pressing the right rudder peddal down or moving the rudder by hand??? I had full rudder travel stop to stop, but not with the peddal.
Good words, Roesbery. I have seen a couple of airplane with damaged/collapsed cable fairleads/pulleys/brackets and the flight control did not receive full input due to the control cables not passing along the full pilot input. An incorrect length rudder cable or damaged system could fail in this manner.
'53 B-model N146YS SN:25713
50th Anniversary of Flight Model. Winner-Best Original 170B, 100th Anniversary of Flight Convention. An originality nut (mostly) for the right reasons.
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