Author Topic: Elevator Travel/Angle  (Read 405 times)

Offline Kiwi55

  • Full Member
  • ***
  • Posts: 68
  • Cabin Eagle
  • Eagle Type: Cabin Eagle
Elevator Travel/Angle
« on: December 20, 2016, 06:38:36 AM »
I'm working on the controls for my Cabin Eagle. I'm going to be using a torque tube for the elevators.
I'm looking for the amount of travel the elevators should have.
I've seen references for as much as 45degrees up, to 25degrees up and 20degrees down.
Can anyone tell me how much travel their Double Eagle elevators have?

Thanks...Paul

Offline Tom H

  • Beta testers
  • ***
  • Posts: 304
  • Built/flew LEU, built/flying DE
  • Eagle Type: DE, LEU
Re: Elevator Travel/Angle
« Reply #1 on: December 20, 2016, 07:45:25 AM »
Paul, DE Stubby has up elevator limit at about 40-45 degrees from neutral.  This is not as original/as per plans.  I don't remember what the original was, but probably around 35-40 degrees.  We modified the controls to get this much up elevator.  The reason is that we were fighting a too-forward flying CG, and the airplane would not flare well when landing with power pulled back to idle.  Eventually we got the CG further back, and the extra movement is not required.

The key is to get your DE flying CG to around 28 - 30% of wing cord back of the wing leading edge.  That's about 15 to 16.5 inches aft of wing LE.

By the way, the only time you may need much down elevator is when raising the tail on take-off roll; otherwise, you don't need much down elevator, and you don't need as much down as up.  So, when making the elevator cables and setting the neutral stick position, keep this in mind.  Build in a bit more up than down.
Tom H
Stubby, a BDE
Treehugger, LEU

Offline MrG

  • Full Member
  • ***
  • Posts: 156
  • Builder - Pilot
  • Eagle Type: DE E-77
Re: Elevator Travel/Angle
« Reply #2 on: December 20, 2016, 12:20:13 PM »
I cant give you angles but this is what i have from the center line and as Tom said, COG is paramount to get right to have it fly right,
im running 26% to 27.8% range, all my flying has been 850 to 900 lbs (just me in plane) and happy with the feel and what im use to flying 
It does have to be reweighed as so many mods & now i can put a passenger in that my change  - Ill find out this weekend  as we do
some full weight tetsts
Best mod ever is the RV like torque tube set up for elevator - so easy to set up
MrG
Temora Airport  Australia
1st Aussie DE built / Flown
19-8866
-----------------------------
1 Oct 2015 First Flight
11 Oct 2017 - 89 hrs Flown

Offline Kiwi55

  • Full Member
  • ***
  • Posts: 68
  • Cabin Eagle
  • Eagle Type: Cabin Eagle
Re: Elevator Travel/Angle
« Reply #3 on: December 20, 2016, 12:55:51 PM »
Thanks Tom and MrG.
I have the torque tube control pretty much built, will need to move the pivot points around a bit to get the appropriate amount of travel. And I still need to build control stops.
I modified the controls a bit by putting the control stick up closer to seat height and back so that it is between the seats near the forward position. The torque tube for the ailerons is above the pivot point (similar to the plans), while the tube for the elevators is below. At the moment I have two pivots in the elevator control tube (I'll post a picture when I get it assembled).
Still along way from measuring and setting the C of G but I appreciate the advice.
...Paul