AOA At Cruise Speed

[Craig Van Sickle]

My question is directed towards folks that have flying LSAs, but I'd be curious for the other Bearhawks as well:

At normal cruise, what would you estimate the fuselage angle? The datum is parallel to the floor mid cabin. Wing is +2 deg, tail is -2 deg. What would your rough estimate be? Is the floor pretty much level or pitched back a degree or two? I know weight/cg impacts this, so let's say at the LSA gross of 1320lbs.

I'm working with the wife laying out our seating with some special accommodations and we were both curious about the fuselage orientation in cruise flight.

Thanks!

 

[robcaldwell]

I'm pretty sure mine is zero (4 Place B Model). My ADAHRS sits directly under my pilot seat. I did not have to adjust the attitude indicator on my EFIS to adjust for +/- deck angle.

 

[Craig Van Sickle]

I'm pretty sure mine is zero (4 Place B Model). My ADAHRS sits directly under my pilot seat. I did not have to adjust the attitude indicator on my EFIS to adjust for +/- deck angle.

Thanks Rob, appreciate that info. I'd guess something similar with the LSA being close to zero. We had a good time yesterday working out the seating; it's good to keep the lady of the house comfortable and happy

 

[jaredyates]

I would think that it is a design goal to keep the fuselage angle close to zero at cruise, to reduce drag. Naturally it would be higher at lower speeds in level flight.

 

[Nev]

Craig, these are the pitch attitudes that I recorded last week on my B model 4-place. Cruise at 120 KTAS or above was slightly negative, and zero at 115 kts. Probably for me the aspect that affects comfort the most is the angle of the seat back. I may yet incline mine a few degrees more towards the vertical.

​

 

[Craig Van Sickle]

Craig, these are the pitch attitudes that I recorded last week on my B model 4-place. Cruise at 120 KTAS or above was slightly negative, and zero at 115 kts. Probably for me the aspect that affects comfort the most is the angle of the seat back. I may yet incline mine a few degrees more towards the vertical.

​

Thanks Nev, that's great information. We were noticing the same thing with the seat back angle. Ellie preferred a little more reclined and I liked a more upright position. Everybody is a little different and sometimes a little change adds a lot of comfort.

 

[rodsmith]

I built all my seats so the seat back angle could be adjusted while on the ground.

 

[Craig Van Sickle]

I built all my seats so the seat back angle could be adjusted while on the ground.

Doing the same here with the ability to tip them forward flat against the bottom cushion as well. We were investigating how much range would be needed for adjustment. Being 6'4" one of factors that lead me to experimental is being able to customize seating. That and I love to build The majority of planes I sit in I'm bumping knees, head, elbows, on something. I love flying in my buddies Glasair 2S but I'm packed in like a sardine.

Did you use a series of holes for a pin or some type of threaded adjustable stop?

 

[rodsmith]

I used threaded bushings for 5/16" bolts that the bottom of the side tubes sit on.

 

[Hewko]

Rod, do you have any pictures. I'm hoping to make my seat angle adjustable in flight. Having a comfortable seat is a big issue for me, I built head rests that should help on the long flights.

 

[Craig Van Sickle]

Rod, do you have any pictures. I'm hoping to make my seat angle adjustable in flight. Having a comfortable seat is a big issue for me, I built head rests that should help on the long flights.

I'll be pulling from the concept bellow. Forward hinging with an adjustable stop that sets the back angle.

 

[Sir Newton]

I like it! Simple & Functional. However the design needs a forward stop.
Seats that use rollers in the seat slide mechanism generally only work correctly for a few years. The rollers end up breaking & never get repaired.