Recently Running Out of Elevator

[Baloo]

(4 Place) In the past when coming in for a short landing I have been able to comfortably approach with full flap at 45-47kts. For some reason lately it feels as if I am running out of elevator closer to 55kts. I haven’t made any changes to the aircraft in quite some time. Does anyone have any suggestions?

Either I’ve been flying so many different types lately that my feel is off, something has changed or I’m going crazy.

thoughts?

[AZBearhawk272]

Density altitude, IAS calibration needed, idle RPM changed, elevator cable stretch / tension. CG further forward, operating on lower fuel level?
is your landing rollout longer?

[jaredyates]

I was going to ask about CG but Kevin has even more great ideas. Do you have downloadable data where you can check IAS vs ground speed? It's much easier to analyze after the fact rather than when you are trying to flare. You might also check elevator travel, that should be quick and easy.

[zkelley2]

Have you had the elevators off recently?

[Baloo]

Thanks for the replies!
To answer the questions.
1. Density Altitude always pretty close to SL
2. IAS is accurate
3. Idle RPM no change noted
4. Elevator cable stretch/tension (Possible) [What is the optimal tension?]
5. CG No Change
6. Fuel Level same as always (no impact before)
7. Roll out isnt much different. I can still slow it down in ground effect and get on the brakes but i seem to be out of elevator.
8. I can get downloadable data out of the MGL I think but I can see the IAS/GS but I can feel myself running out of elevator/lift sooner that I seem to remember before.
9. Elevators / Horizontal stab have never been off.

[svyolo]

I think you would feel looseness in cables. You might not feel a change in the length of the elevator pushrod connected to the stick, other than running out of control authority either up or down.

Or like you said, you have been flying "other" things, and now the BH feels different.

[zkelley2]

Do you have drains in the trailing edge(ish) of the fabric? How big are the holes for the fabric around the elevator attach points(are they bigger now?)

Two things that can wildly change an airfoil are water in it(weight) or the shape itself in the case of it blowing up like a balloon.

[Bcone1381]

Baloo, A key word I see in your two post's is Feel. Is there any hard data available as opposed to a feeling? Why does it feel this way? What is different? Since you have been flying a lot of different aircraft lately, could that effect the "Feel" of things.

Is your stick reached the the stops in the landing flare with full flaps. Does your elevator hit the stops in slow flight and stalls in landing configuration? Can you get some additional data in slow flight? Do you have any old data to compare todays data with?

[Gerd Mannsperger]

A slight amount of power at the same speed will give you more airflow and elevator control. If you start coming in faster and slow down quick to the same speed by cutting the power back more will reduce your elevator control due to less airflow. If you have been flying many different types lately there is a good chance you have changed your flying technique slightly.
Try to slow up a bit further back and come in with a sight bit more power. I am a firm believer in gap seals and VGs on the bottom of the horizontal stab.

[kestrel]

...what he said.

[zkelley2]

What is your CG when you feel like you run out of elevator?

With just me in the airplane, I can fly an approach all day at 45kts and have a bunch left over for the flare. My CG with just me and 50 gallons is 14.25".

[Rollie]

"Feels" like you are running out of elevator. You could try some stalls and find out if it is actually different.

[swpilot3]

You might check your flaps. Are you still getting the full 50-degree deployment? I found that my flap cable assembly stretched and I lost about 5* of flaps. That might account for making it "feel" different.

[Baloo]

Lots of interesting thoughts!
i used to be able to approach comfortably at 45kts with full flap and the elevator not quite at the stop. Today I was approaching at 50kts on the stop and felt the the bottom was going to fall out. No water in the control surfaces. But will definitely check flap rigging. My plane never breaks in the stall, it just mushes down and can be recovered with power alone. I did try slowing earlier today with better results but still 50kts on the elevator stop with nothing left to flare. I’ll run a CG tomorrow.

[Rollie]

That is definitely strange. Just to make sure I understand correctly, you flew final at 50 kts with the stick all the way back? That seems like if it's not cg then maybe somehow you aren't getting full up elevator. Not sure what might have changed, other than a cable stretching, but I think someone else suggested that a few days ago. Have you checked the elevator for proper deflection up and down? I'm sure you had it rigged properly and it doesn't seem like something that should change that much, but the only things that make sense to me are: not getting enough up elevator or a significant forward cg shift. Flaps will make a difference in stall speed and deck angle, but I don't think it would account for you running out of elevator like that.

Just out of curiousity, can you get it to fly slower power on?

Have you always had the ABW tires? When I put 31's on my Patrol, I couldn't 3 point anymore unless I carried 50 lbs in the baggage compartment. Full aft stick would result in a wheel landing with the tail a couple feet off the ground. I don't remember what the cg was but on paper it didn't seem like a big shift forward and it was in limits.

[500AGL]

Trust but verify.

As others have said -
- Density Altitude. (And simply Temp) Victoria can't always be cold and at sea level?
- CG.
- CG. Yes I put this here twice. Make sure you're well back from the front limit.

pb

[zkelley2]

I would check the deflection angles you're getting on the elevator.
This is a very similar problem to one I had when I did my first few flights. I had put the elevators on and rigged everything in my garage probably 6 months before I actually finished. In that time I moved the whole project and that included taking them off. I didn't think anything of it when I put them back on, didn't re-check the angles. Turns out the control horn on the elevator, despite looking like it's 90 degrees(perpendicular) to the elevator, it's offset something like 6 degrees iirc. The plans make no meantion of this. This means there is a left and a right and they have to be on the right way or you'll hit the stops before you get to the correct deflection. Running out of elevator in the flare.

[robcaldwell]

Elevator Control Horn Angle... I'm putting this on my "to-do" list when I install the elevators (should be soon). I don't think I've read about this anywhere else.