• If You Are Having Trouble Logging In with Your Old Username and Password, Please use this Forgot Your Password link to get re-established.
  • Hey! Be sure to login or register!

180 tailwheel

T.J. said:
So, can we assume from this test, that the difference in weight between 3 point and level is not "miniscule"?
Can I do my weight and balance calculations from the 3 point attitude now? :D

OK, I might have overstated that a little :oops:
 
_38520125_worms_150_eyewire.jpg
 
Stewart, I really appreciate your effort in getting real facts. I recognize that this was real work. I enjoy my C180 in addition to my PA-12. This is great information. Hard facts like this make this a great site.
 
You're welcome.

While we all know pilots that cringe at the thought of weighing their planes because they know they'll lose useful load, I'm a fan of accurate data. When my 180 was stock and had a max gross of 2800#, I recognized I had physical space and available performance to carry more than that. I saw a value in adding Kenmore's 3190# gross weight STC to utilize the capabilities while not exceeding defined and stated limitations. To have made the effort to increase my legal load makes compromising that gain unacceptable. On the flip side, it appears that the Baby Bushwheel is perfectly appropriate for older, lighter grossing 180s. The applicability for standard 2800# 180s is harder to anticipate. Those owners will need to decide for themselves.

Aalexander, my empty CG is +36.3. The gross weight/600# tailwheel load configuration was at +46.3 (my aft CG limit is 47). I have a nose heavy airplane. I don't mind because I never fly without gear that I use for balance. I had about 180# of fuel on board for yesterday's test. It would have been fun to fill the tanks and see what effect it had. If I'd had more time I could have loaded in two or three configurations and graphed the changes but such a graph would only be applicable to my plane and I had already found out what I needed to know.

I had flown to Birchwood with three relatively soft tires. We were forced to increase the pressure in the 29" mains to keep the plane centered on the scales. While my tailwheel had looked normally inflated on arrival when the plane was essentially empty, by the time we had it to gross the tailwheel was very nearly resting on the wheel with the tire squished flat. I increased the pressure to the point that I had a normal 1/2 to 1" flat contact patch on the tailwheel. Before flying home I deflated the mains back to 10# but left the tailwheel alone. Upon taxiing out the same way I had arrived, the noise and roughness transmitted by the hard tailwheel on my now empty tail was alarming. It made me wonder how the Baby Bushwheel would perform given the same circumstances. Another test might be in order. Enquiring minds want to know.

Stewart
 
Wup,

My interest in this topic is centered on my airplane and my responsibility as a pilot to operate the airplane within it's limitations. I didn't pick the 500# max static load limit, ATR did. Even if your formula is flawed, ATR is protected by the 500# limit that's emblazened on your tire.

It's my nature to question statements of fact that don't add up. That's exactly what I did here. No calculations, just a certified scale. To eliminate errors, the weigher insisted we not just weigh the tail as I had planned. Instead, we weighed all three gear positions. Having done so, I'd submit that your formula is incorrect. The tail weight you're reporting would be found at a gross weight of approximately 2850 to 2900# using my plane. I would suggest that the subject is in question enough to warrant validation of your data. It seems the timing may be perfect, since there's a display show this weekend. Personally I have nothing to gain here. I did the test and found a weight condition that was significantly less than my original estimates. Oddly, it's significantly greater than your estimates. I'd hope a manufacturer of an STC'd product would be motivated to find the truth.

You can borrow my plane if you'd like to test your formula.

Stewart
 
I am just showing you how the test was done and certified by the FAA



and that's the Truth
 
Fair enough. I was just trying to find out how much it really weighed.

Stewart
 
SB-

I have written many responces to this post but here is the best one


Have a Nice day. 8)
 
I just want to say ”Thanks! 👍” to Stewart for this still-relevant data collection. Nice work!
J

With the help of a professional airplane weight and balance mechanic and 20 sand bags, I did my test to see what the actual tail weight is at gross weight in three-point attitude. I had previously overestimated the total weight, but he weight still exceeds that allowed by the Baby Buswheel.

The test plane is a 1975 180J with a few tricks added. I had a weight and balance done a couple of years ago and as it sits with all these tricks it weighs 1876#. In level flight attitude the tail weight is 130#. In three point it's 200#. So, I experience a 53% increase in the three point with no other changes. My gross weight is 3190#. Today I had the plane on certified scales and loaded it with sand bags in a well-distributed load that took it to 3190# and was within legal CG. The tail weighed right at 600#. I could have played with the loading and changed it a bit up and down, but this is a representative weight while in a normal (legal) load distribution. Without question a 3500# 185 would have 700# plus in a similar test.

For estimating purposes I can divide my plane's total gross weight into five parts. Each main carries approximately 2/5 of the weight while the tail carries 1/5. This is not perfect by any means, but it works on my plane.

I wanted to know, so I paid my money and found out. No speculation, no smoke and mirrors, no BS. There it is.

Stewart
 
No formulating. The plane had been weighed fairly recently (at that time) and the three point numbers matched. My tailwheel weight was taken in 3 point. All I did was add more sandbags. Pretty straight forward.
 
Back
Top