The International Cessna^® 170 Association

I don't know about longer gear putting more weight on the tail than the stock length gear legs. But my plane has the later-model 180 gear, which is raked forward about 3-1/2" more than the stock 170 gear. This very definitely puts more weight on the tail, as it moves the mains farther ahead of the CG.
BTW, my W&B sheet shows that there was 1203 pounds on the mains & 115 pounds on the tail when it was weighed (empty) in 2003. An earlier weigh-in from 1960 showed 1198 pounds on the mains & 93 pounds on the tail, with the stock gear legs.

Eric

I'm not sure that's apples-to-apples, Eric.
I suspect the difference is to be found in other changes to your aircraft's wt & bal and/or the weighing system and errors.
For example, wouldn't the fact that 180 gear legs weigh more than 170 gear legs somewhat account for in that 5 lb. difference between the gear legs?

FWIW, my '54 with stock (lady) legs weighs
95 lbs at the tailwheel. The relative forward
location of the axles (C-180 gear) will put more
weight on the tail.

I've flown two early 180s, one with stock gear and
one with C-185 gear, and the 185 gear'd one was
noticeably heavy at the back end (full power and
bury the yoke in the panel, and the tail still wouldn't
come up until you got some wind under it). Do that
in a stock/early 180 and you'd end up on your nose!

Full of fuel and oil, (BOW) my tailwheel has 149 lbs on the scale. Adding two rear seat pax, and some baggage, and my usual 3-point "carrier landing" technique, considerably more stress is placed on that little wheel. Using that as a guide, I doubt the 180 gear conversion and it's few inches forward placement of the main axle overly-strains the tailwheel, if that's the reason for this special dicussion. (not to mention that the gear legs are still attached to exactly the same fuselage position anyway. The amount of uphill angle of incidence places a negligible amount of additional weight upon the tailwheel, I imgine.)

I think the idea is simply that there is more weight
back there with the 180 gear and it can make for
unpleasant ground handling (I personally don't like
the tail being that heavy). I suppose one could argue
increased weight on the tail could shorten tailwheel tire
life

FWIW, I'm sure the stock tailwheel spring(s) can handle
the extra weight (and even the carrier style landings!).

I don't understand.
If we don't like additional weight on the tailwheel....then why do we taxi with the elevator in the up position?

gahorn wrote:I don't understand.
If we don't like additional weight on the tailwheel....then why do we taxi with the elevator in the up position?

For the A model, it's to reduce stress on the bulkhead from the heavy elevators banging around if not held in the up position.

That was a rhetorical question, intended to cause reflection on how little import a slight additional weight might affect handling.
The reason we taxi with the elevator in the up position (yoke/stick held aft) is to place additional weight upon the tailwheel (derived from prop blast) to increase effectiveness of tailwheel steering and to avoid nosing over during emergency stops. It has nothing to do with bulkhead stresses or unbalanced elevators. (Full down elevator would also combat such, as would neutral elevators.)
The point being that additional weight upon the tailwheel (if any/however minute) would be an improvement to handling, not a detriment.

gahorn wrote:I don't understand.
If we don't like additional weight on the tailwheel....then why do we taxi with the elevator in the up position?

The issue for me is how much I can lighten the tail when
I want to with a blast of power. I find that I prefer the
stock gear (both on the 170 and early 180) in that regard.

The stock 170 / early 180 gear gives you plenty of "tail planting"
authority (full-up elevator) when you want/need it, but also
lets you pick the tail up with full forward elevator and a blast
of power in short order (in other words, it's well balanced in
that regard).

gahorn wrote:That was a rhetorical question, intended to cause reflection on how little import a slight additional weight might affect handling.
The reason we taxi with the elevator in the up position (yoke/stick held aft) is to place additional weight upon the tailwheel (derived from prop blast) to increase effectiveness of tailwheel steering and to avoid nosing over during emergency stops. It has nothing to do with bulkhead stresses or unbalanced elevators. (Full down elevator would also combat such, as would neutral elevators.)
The point being that additional weight upon the tailwheel (if any/however minute) would be an improvement to handling, not a detriment.

Neutral would work. But full down elevator would allow the heavy A elevator to bang up and down very hard. The bumpier the taxiway, the harder the banging. Can't possibly be good for the airframe.

I didn't mean relaxed in the down position. I meant FULL down,...as in the Yoke Held full forward with similar pressure as it might be held full up. With the elevator held firmly against either stop, it would prevent banging. (But in any case that's not the reason it's normally held full up. And the entire question was in order to demonstrate what a small matter it is to have such an infinitesmally small additional weight on the tailwheel as might be imparted by the substitution of a 180 gear for the original 170 gear. We all taxi aroung with just as much if not more down-pressure on our tailwheels by holding the up elevator into the relative wind while taxying...as what additional weight might be placed by the gear substitution.
We're all back to measuring with micrometers what we intend to mark with a grease-pencil and then cut with a hatchet.

George, you missed the gist of my post entirely. Re-read it-- the difference I'm pointing out is NOT the 5 pounds more on the mains, it is the 22 pounds more at the tail. And the increase in weight distributed at the tail is NOT the result of the angle of the gear legs, it is a result of the mains being 3-1/2" farther forward. It's a leverage/geometry thing.

Eric

gahorn wrote:....................
The point being that additional weight upon the tailwheel (if any/however minute) would be an improvement to handling, not a detriment.

Not necesarily so, more weight on the tail ( CG farther aft of the mains) would tend to increase any ground-looping tendencies-- once the tail starts trying to overtake the nose, it'd be harder to straighten out.

Eric

Repeatedly saying that the stock tailwheel spring is satisfactory doesn't necesarily make it so. If it's so satisfactory, why do they break? At least half of the 170's I've eyeballed have had some repair work done to the bottom of the rudder, I'm sure from the tailwheel assembly flailing around on the chains aftera spring broke. I don't believe the tailspring should be a regularly-replaced item like tires or brake pads. Mine has an approximately 10 year old stock mainspring on it, if & when change it I'll probably go with an L-19 spring. NOT a doubled stock main leaf,though--too much of a "good" thing. And I WILL be rounding off the edge of the #2 leaf, as well as the edge of the tailwheel casting--I've seen the springs break there too.

Eric

gahorn wrote:I didn't mean relaxed in the down position. I meant FULL down,...as in the Yoke Held full forward with similar pressure as it might be held full up. With the elevator held firmly against either stop, it would prevent banging. (But in any case that's not the reason it's normally held full up. And the entire question was in order to demonstrate what a small matter it is to have such an infinitesmally small additional weight on the tailwheel as might be imparted by the substitution of a 180 gear for the original 170 gear. We all taxi aroung with just as much if not more down-pressure on our tailwheels by holding the up elevator into the relative wind while taxying...as what additional weight might be placed by the gear substitution.
We're all back to measuring with micrometers what we intend to mark with a grease-pencil and then cut with a hatchet.

George, the amount of weight added to the tail by putting (later)
180 gear on a 170 is not "infinitesimal". A little added weight back
there goes a long way. The early 180s I referred to in an earlier
post are both '53 models, are both similarly set up (Atley Dodge
rear seats, just about the same everything else except the gear
legs). One has stock / original '53 180 gear legs, the other later
model 185 gear legs. The latter is a pig on the ground handling-wise
(the tail is simply too heavy). I realize this is a personal opinion, but
wanted to get the point across that if you do opt for the 180 gear
that has the axles moved forward, it will feel "significantly different"
on the ground (the tail will feel darned heavy indeed). Maybe some
folks like the tail so heavy they can't pick it up off the ground with full
power and full forward yoke. I happen to not like it that way.

I'm thinking Cessna moved the axles forward on the later model
180s because the front end of the airplanes got heavier and heavier
with each subsequent model year (an -R or -K O-470 is 35-45 lbs heavier
than an -A or -J). If they didn't move the axles forward, the later
model airplanes would be too easy to tip over onto their noses
with maximum effort braking.

Once again, we're back to the idea that Cessna did a fantastic
job from the get-go of designing the landing gear for the airplane in
question. Swapping parts out for "heavier duty" 180 parts (such as
gear legs) can have advantages as well as disadvantages.