Making your Bearhawk too light - the best way to ruin a good airplane!

[jim.mclaughlin924]

I used grade 5, 6AL-4V which is can be machined in the treated condition as is about as strong as can be used for a spring.

[Bdflies]

I spent a lot of time dealing with metals and their properties, but I have to admit near ignorance of titanium. I know it's really light and really strong. If Jim, or other, comes up with a titanium replacement (in an appropriate condition) for the rod type tail spring, please let me know. I'm interested!

Bill

[Mark Goldberg]

Titanium has to be hardened or it will bend quickly. Mark

[Archer39J]

What kind of titanium did you use. 1.5 lbs at that STA is appealing...

[jim.mclaughlin924]

Bill
I made a tapered Ti spring for my Patrol, Not flying yet, so can't say it is successful, but it is pretty soft compared to the steel one.

[Bdflies]

At some point, there was discussion of a titanium rod tail spring. If someone came up with such, I'd be interested. That would shave a noticeable amount, from the rearmost arm.

Bill

[svyolo]

The tail spring is really heavy. I have a model B round spring. I am not sure there isn't a better way. Working on it.

[Battson]

Jon, now that you are back in the air, has there been any resolution of the aft cg issue? Has it changed how much you can carry? Sounds like you are happy with the performance.

At this stage we are just living with it, we have a new young son who takes up most of our time

I still plan to move the battery forward and remove the baggage tube. I have done the calculations and the baggage tube is the best way to make a big difference. That change should theoretically allow us to carry four average-size adult men and full fuel once again, instead of three and a half!

[rodsmith]

Jon, now that you are back in the air, has there been any resolution of the aft cg issue? Has it changed how much you can carry? Sounds like you are happy with the performance.

[JimParker256]

Thanks, everyone. I knew the answer was there somewhere. Some days you can't see the forest for the trees...

[rodsmith]

You can use the lower longeron as noted on the plans. I would verify the measurement there by scaling the distance from the bottom of the tailpost to the thrust line, probably 2 to 3 inches, and using a water level from the center of the prop flange, or the tip of the spinner if the prop is installed back to the measurement below the tailpost. That is how I leveled my Bearhawk to set the wing incidence level.

[Bcone1381]

Forgive me, for I am anel and with little bit of Missouri (The Show Me State) blood running thru my bones. This is on the Patrol Plans p. 1. Datum Level note is at the two O'clock position in relation to the main wheel.
Screen Shot 2018-04-06 at 6.45.03 AM.png

[Mark Goldberg]

You level your plane front to back using a section of the lower longeron just aft of the L/G. Mark

[bergy]

Yes ... there is a center-line on the Patrol drawing... a long dashed-line (I do not have my drawings with me right now) If I remember correctly, the floor of the cockpit is parallel to the longitudinal center-line. There is also a measurement showing how far above the bottom of the fuselage the base of the tail-post should be in level flight.

[JimParker256]

Battson,

How did you level your plane when weighing it? Does Bob specify a specific "line" to be used to achieve the "level flight" attitude? I'm looking in my plans, but not seeing it.

Sorry for the "sort of" thread hijack...