[aarvig]

I've read the threads about electric vs. manual elevator trim and it seems to be a matter of preference. I am wondering if anyone with manual elevator trim would post a pic of their finished cockpit installation. I am wondering if anyone has tried installing a manual elevator trim with a different setup than the installation Vans recommends (it looks like it may get in the way of the legs). Any opinions regarding the manual installation would be appreciated.

 

[Mel]

Not sure which RV you have, but my RV-6 has been flying for over 16 years with the manual trim installed per plans and has never been in the way. The only thing different about my installation from the plans is that I eliminated the vertical panel from the fuel selector to the panel, but the trim is in the same place.

 

[hydroguy2]

I plan on moving my manual trim to the left, under the throttle quadrant(also on the left). Here's a couple of VERY rough planning/staging photo's. I'll be rerouting the cable and fabbing throttle mount first, then trim mount.

 

[RV7ator]

I've Tried Both

Two RV-7s I've built had the standard Van's manual cable installation. The loop from the knob around under the spar doesn't really get in the way, but the knob poking up over the fuel valve and the edge of the mount plate may prove annoying to your legs if you sprawl a bit. The loop simply looks sloven.

So the current -7 has the knob between the seats facing forward positioned over the spar carry through. It's a nightmare fitting it in so it looks good, easily functioned, the seat pans are removable, and the cable clears the nearby roll trim mechanism. The knob still can be a knee banger, and you might tickle your passenger's thigh, but overall it's a more compact installation than standard to my way of thinking.

The current project will have electric pitch trim. The manual works well, but there is enough lash in the cable to move the trailing edge of the trim tab though several degrees, which will bounce you around the cockpit if it were suddenly deflected through the range. The electric installation won't have any lash. This lash might be contributing to the Dynon autopilot pitch trim difficulties I and others have experienced, and it makes fine tuning the manual trim a bit touchy, though it does seem to hold once set.

John Siebold

 

[gasman]

The manual works well, but there is enough lash in the cable to move the trailing edge of the trim tab though several degrees, which will bounce you around the cockpit if it were suddenly deflected through the range.
It makes fine tuning the manual trim a bit touchy, though it does seem to hold once set.

John Siebold

My manual trim is installed per Van's and don't have any problem with lash in the cable.
But when you move the cable from the location on the plans, and move it farther back like between
the seats, then you make s turns to fit the cable that is now too long, this will cause play in the cable
that you won't get if you install with only one bend as per plans.

 

[kiwipete]

FI needs longer cable

Another thing to consider is if you have a fuel pump for FI in front of the manual trim buy the RV8 cable as it's slightly longer.

I have a manual trim and wouldn't swap it!

Peter

 

[L.Adamson]

Another thing to consider is if you have a fuel pump for FI in front of the manual trim buy the RV8 cable as it's slightly longer.

I have a manual trim and wouldn't swap it!

I've heard from many who wouldn't swap from manual trim also.

However, I have electric trim for both elevator and ailerons on the stick's hatswitch. It has been working extremely well!

L.Adamson --- RV6A

 

[RV7ator]

Too long a cable is not a problem. Have Van's shortened by a Cablecraft dealer, or order a custom unit. Contemplate the weight you save! he said while munching a doughnut. Having tried this route, I don't recommend the 'tween-the-seats installation because of its complexity, which changes nothing of the functional characteristics of the manual, only appearances. KISS.

BTW, Gasman, the belts are boxed.

John Siebold
Boise, ID

 

[aarvig]

Thanks for the advice and photos. I like the left side throttle and cable installation. Looks good! I have heard from many as well that they would stick with manual over electric trim as well. I have also flown an RV-7A with electric trim and for the life of me I could not trim it out, it was so touchy. Maybe that is just the pilot and not the plane but I felt I was chasing the trim the whole flight.

 

[L.Adamson]

Thanks for the advice and photos. I like the left side throttle and cable installation. Looks good! I have heard from many as well that they would stick with manual over electric trim as well. I have also flown an RV-7A with electric trim and for the life of me I could not trim it out, it was so touchy. Maybe that is just the pilot and not the plane but I felt I was chasing the trim the whole flight.

On the other side of the coin, I've had comments on how well my 6A with electric trim for roll and pitch.......... trims out. I initially thought about
the speed controllers, but it doesn't need them. BTW, my aileron trim is the piano hinge type on the aileron (servo controlled). This is the "old way", with no bias springs.

Personally, I prefer working trims from the stick, rather than reaching down between some "fat guys" sweaty legs..

L.Adamson

 

[islandmonkey]

Trimming

Thanks for the advice and photos. I like the left side throttle and cable installation. Looks good! I have heard from many as well that they would stick with manual over electric trim as well. I have also flown an RV-7A with electric trim and for the life of me I could not trim it out, it was so touchy. Maybe that is just the pilot and not the plane but I felt I was chasing the trim the whole flight.

As a part time flying instructor for more than 15 years and having taught around fifteen people to fly and checked out countless dozens of pilots, I have found that many pilots do not know how to trim correctly. It does not matter if there is manual or electric trim installed, I had to go over the correct technique for trimming. Always the pilot would be moving the trim without holding the stick or column at the correct attitude and trimming out the stick forces.

I am not saying that this is so in your specific case, this is just a comment on the experience or inexperience or sloppy flying that I have encountered.

I have sampled a number of aeroplane types with electric trim where the trim speed was set to coarse. I found it very difficult to trim correctly and was hunting around trying to get the plane correctly set much longer than if manual trim had been installed.

Give me manual trim every time, I much prefer it.

 

[aarvig]

As a part time flying instructor for more than 15 years and having taught around fifteen people to fly and checked out countless dozens of pilots, I have found that many pilots do not know how to trim correctly. It does not matter if there is manual or electric trim installed, I had to go over the correct technique for trimming. Always the pilot would be moving the trim without holding the stick or column at the correct attitude and trimming out the stick forces.

I am not saying that this is so in your specific case, this is just a comment on the experience or inexperience or sloppy flying that I have encountered.

I have sampled a number of aeroplane types with electric trim where the trim speed was set to coarse. I found it very difficult to trim correctly and was hunting around trying to get the plane correctly set much longer than if manual trim had been installed.

Give me manual trim every time, I much prefer it.

I am a new pilot so that could very well be a factor. The books say "trim to relieve control pressure". I think I have a tendency to try and adjust trim without holding proper attitude. (ie...use the trim lever to get the plane into proper flight attitude rather than use the yoke/stick to get the plane into proper flight attitude and then trim to relieve pressures). I'll give it a go this weekend and see if there is a difference.

 

[islandmonkey]

I am a new pilot so that could very well be a factor. The books say "trim to relieve control pressure". I think I have a tendency to try and adjust trim without holding proper attitude. (ie...use the trim lever to get the plane into proper flight attitude rather than use the yoke/stick to get the plane into proper flight attitude and then trim to relieve pressures). I'll give it a go this weekend and see if there is a difference.

Seriously Aaron, there is no way you can trim an aeroplane correctly just by using the trimmer to move the nose up or down. There is no frame of reference to judge when the plane is in trim. By holding the correct attitude for straight and level flight and then trimming out the stick forces, you have a frame of reference to judge when the plane is in trim. Give it a try and let me know how you get on. Good luck and keep an eye out for other aircraft.

 

[L.Adamson]

I have sampled a number of aeroplane types with electric trim where the trim speed was set to coarse. I found it very difficult to trim correctly and was hunting around trying to get the plane correctly set much longer than if manual trim had been installed.

Give me manual trim every time, I much prefer it.

But..............you don't have to own an airplane with "coarse" electric trim. The are speed controllers on the market to allow any adjustments that you may wish.

As to myself, I always preferred to rent newer airplanes; rather the standard worn out, rental... has beens. The newer models always had the refinement of electric trim, and I'm spoiled...........I guess.

L.Adamson ---- RV6A (flying)

 

[islandmonkey]

Refinement?

As to myself, I always preferred to rent newer airplanes; rather the standard worn out, rental... has beens. The newer models always had the refinement of electric trim, and I'm spoiled...........I guess.

L.Adamson ---- RV6A (flying)

My personal opinion is that electric trim in light general aviation aircraft is not a refinement. You need electric power available to operate the trim motors which are generally located in the most inaccessible places. The added risk of trim runaway (small though it is) also puts me off. The worst thing that can happen in a manual system is that the trim wire breaks when set up for landing and a subsequent go around is required. Stick forces for an out of trim climb in this case can be very hard to counter but this is the same for both manual and electric systems.

Manual trim systems are also generally lighter than electric systems.

 

[flyvans.com]

just as a data point in the discussion:

i just recently transition -trained with jan bussell on his 6A in anticipation of our first flight sometime within the next year...
also having spent some time thinking about failure modes, electrical system (we install a vp200) etc...

trim speed was no problem, maybe a tiny bit slow during slow flight and a bit too fast in level cruise flight. we had originally planned to put in an r.c.allen trim speed controller, now the vp200 should take care of that but the RV is absolutely flyable without any.

runaway trim in these airplanes is a non-event!
other than having to monitor airspeed more closely, the out of trim condition only causes slightly higher control forces, about what would be normal in another airplane.
absolutely no risk of PIO or having to use 2 hands or any other form of typical runaway-trim-horror-stories.
we made both landings with full up and full down pitch trim! and nice ones, nothing unusual about them.

with higher speeds, forces are higher of course and you'd definitely notice a runaway condition and have to slow down. however, it does not lead to loss of control!

rgds,
bernie