Trim system
Posted: Mon Aug 21, 2023 3:22 pm
by Tony4aro
Hi All,
I have the Sonex dial-a-Trim system on my waiex. I’m still building it… and I installed the system to the plans. (Rear spring just snug full forward, and full up, the tab is about 1/4" from the cable housing) When in this configuration… it seems like it’s holding up elevator at mid travel. It almost seems like too much up trim is available. I know it’s all new and tight, but I was wondering is someone could post where there elevator sits when it’s on the ground, and if my description sounds right. I’m wiring my panel now… and I still have full access to all of it, if I need to adjust something.
Thanks
Re: Trim system
Posted: Mon Aug 21, 2023 3:52 pm
by Bryan Cotton
On the ground, my stick will pretty much move full range when I crank my trim.
Re: Trim system
Posted: Mon Aug 21, 2023 4:19 pm
by Tony4aro
Bryan Cotton wrote:On the ground, my stick will pretty much move full range when I crank my trim.
So… full down trim is close to full forward stick, and full up trim is close to full back stick? If that’s right… then I guess I’m in the right place. So… on a normal take off… where is your trim?
Re: Trim system
Posted: Mon Aug 21, 2023 5:12 pm
by Bryan Cotton
I usually trim for 80kts on takeoff. The Aerovee doesn’t climb well at low speeds, plus it gets hot. So 4-5 turns forward of the aft trim stop for me. Depends on fuel and CG.
I put a little crank knob on mine. Highly recommended!
For a first flight you can either use my recommendation or put it in the middle. Even with trim set wrong forces are light.
Re: Trim system
Posted: Mon Aug 21, 2023 7:49 pm
by Panther16
I don’t think you need to worry about the trim until you do the weight and balance and find out where the cg is. I originally built my Sonex with the Aerrovee. After 80 hrs I converted to aJab 3300 due to performance issues. With the 3300 my cg is close to the fwd limit, about the base of the instrument panel. My dial a trim is adjusted so the elevator is about 1 in up from neutral at full nose down on the dial. Every thing you put in the a/c along with fuel burn moves the the cg aft. 4 turns up gives 70 on final and any from 3 -4 turns in cruise depending on speed. I suspect you may have the same issue if are using a corvair and don’t add some weight in the tail.
The only issue with the way it is adjusted is on a go around you need to take out 2 turns otherwise the stick force gets very hi holding the nose down.
Keith Rhode
Sonex 214KE
Re: Trim system
Posted: Mon Aug 21, 2023 7:54 pm
by Bryan Cotton
I agree that CG is a big effect on trim. Also here is a picture of the knob I put on my dial-a-trim.
Re: Trim system
Posted: Mon Aug 21, 2023 10:16 pm
by daleandee
Panther16 wrote:Every thing you put in the a/c along with fuel burn moves the the cg aft. 4 turns up gives 70 on final and any from 3 -4 turns in cruise depending on speed. I suspect you may have the same issue if are using a corvair and don’t add some weight in the tail.
My Odyssey is in the tail of my Corvair powered taildragger for CG reasons. With full fuel and no baggage a single pilot needs to be at least 180 lbs. But there is no loading scenario (within reason) that takes the CG out of the rear limit.
I have the conventional tail on a Model-A with the original trim lever. At approach speeds with 20º flaps setting I can use full up trim and all is well. Using 30º flap on final causes the need for the slightest touch of back-stick pressure. Some have suggested a slightly larger trim tab but I stayed with the plans. Here’s what it looks like:
Re: Trim system
Posted: Tue Aug 22, 2023 3:16 am
by Panther16
What happens if single pilot below 180? I would have to add 35lbs and I always try to start with full fuel.
Re: Trim system
Posted: Tue Aug 22, 2023 7:46 am
by Tony4aro
Panther16 wrote:I don’t think you need to worry about the trim until you do the weight and balance and find out where the cg is. I originally built my Sonex with the Aerrovee. After 80 hrs I converted to aJab 3300 due to performance issues. With the 3300 my cg is close to the fwd limit, about the base of the instrument panel. My dial a trim is adjusted so the elevator is about 1 in up from neutral at full nose down on the dial. Every thing you put in the a/c along with fuel burn moves the the cg aft. 4 turns up gives 70 on final and any from 3 -4 turns in cruise depending on speed. I suspect you may have the same issue if are using a corvair and don’t add some weight in the tail.
The only issue with the way it is adjusted is on a go around you need to take out 2 turns otherwise the stick force gets very hi holding the nose down.
Keith Rhode
Sonex 214KE
Thanks for the info on that.
I have the forbidden Corvair engine in mine… but from my research, the 3300 really isn’t much lighter once everything is added on. SO… it’s a good match info wise.
Re: Trim system
Posted: Tue Aug 22, 2023 7:46 am
by Tony4aro
Bryan Cotton wrote:I agree that CG is a big effect on trim. Also here is a picture of the knob I put on my dial-a-trim.
Cool. I may do that to mine also. Thanks for the pic.
Re: Trim system
Posted: Tue Aug 22, 2023 7:57 am
by Tony4aro
daleandee wrote:
Panther16 wrote:Every thing you put in the a/c along with fuel burn moves the the cg aft. 4 turns up gives 70 on final and any from 3 -4 turns in cruise depending on speed. I suspect you may have the same issue if are using a corvair and don’t add some weight in the tail.
My Odyssey is in the tail of my Corvair powered taildragger for CG reasons. With full fuel and no baggage a single pilot needs to be at least 180 lbs. But there is no loading scenario (within reason) that takes the CG out of the rear limit.
I have the conventional tail on a Model-A with the original trim lever. At approach speeds with 20º flaps setting I can use full up trim and all is well. Using 30º flap on final causes the need for the slightest touch of back-stick pressure. Some have suggested a slightly larger trim tab but I stayed with the plans. Here’s what it looks like:
Glad to hear from you on the board. I posted another message on one of your youtube vids, but obviously, I didn’t want you to put out any real info on that. Unfortunately, the y-tail can’t use a regular trim tab, and I’m stuck with the dial-a-trim system.
Because of the Corvair weight, I also mounted my battery behind the spar to hep with CG. For convenience, I put it on the pilot side, just behind the seat. That way I can just pull the hinge pin, and get to it. Eventually, I figured I will make a cargo pan out of thin aluminum to keep it all safe. How far back is yours? I saw pics of a battery literally behind the rudder hinge.
Just so I can share… her’s a pic my panel I’ve been working on.
Re: Trim system
Posted: Tue Aug 22, 2023 9:21 am
by Bryan Cotton
Looks good Tony!
I had to make bushings to recess my PTT buttons, else my thumb hit the subpanel.
Also the Waiex will have a more aft CG than a heathen straight tail Sonex. I can’t get on my forward limit unless there is 17 gallons of fuel, a 98 lb pilot, and two helium balloons in the tailcone.
Regarding being stuck with the dial-a-trim, I really like mine. I can trim my full speed range from 60 kts to cruise. At full forward, my nose up spring/cable is slack. If I chucked a Corvair in my Waiex I bet I could shorten the cable and still have my full range.
I bet with the more aft CG of the Waiex that it may be the optimum Sonex airframe for a Corvair installation.
Re: Trim system
Posted: Tue Aug 22, 2023 12:24 pm
by daleandee
Panther16 wrote:What happens if single pilot below 180? I would have to add 35lbs and I always try to start with full fuel.
I’ve got 180 lbs. covered by at least 10 lbs. on a good day. 8~)
My remedy (if needed) would be to put weight in the cargo area behind the seat, or add some weight under the seat itself (I used to use a removeable barbell weight with a Challenger II for light weight pilots), and a last resort would be less fuel. There are a few things I could do to move the CG more rearward but as it is now it’s perfect for me and my weight.
I’ve have considered adding an auxiliary fuel tank behind the seat and that would solve two problems (not enough fuel & CG for lighter pilots) but that would add more weight and I don’t need anymore of that.
Dale
Corvair 3.0
Taildragger
Re: Trim system
Posted: Tue Aug 22, 2023 12:26 pm
by daleandee
Bryan Cotton wrote:Also the Waiex will have a more aft CG than a heathen straight tail Sonex.
I’m not the one flying a forked tail devil … 8~)
Re: Trim system
Posted: Tue Aug 22, 2023 12:39 pm
by daleandee
Tony4aro wrote:Because of the Corvair weight, I also mounted my battery behind the spar to hep with CG. For convenience, I put it on the pilot side, just behind the seat. That way I can just pull the hinge pin, and get to it. Eventually, I figured I will make a cargo pan out of thin aluminum to keep it all safe. How far back is yours? I saw pics of a battery literally behind the rudder hinge.
My battery is as far back as it can go (I’ve looked for photos but can’t locate them now). Looking at the airplane from the left side the battery in located in the bay where the rudder cable exits and the access plate cutout is. I can reach the terminals by removing the access plate to attach a charger although I’ve never had to do that. It is mounted to a plate that is bolted to the bottom of the plane. It is a snug fit.
I built a small box for it and it’s held in place with all thread rod on each side with a Teflon top cover. Being in the tail and subject to being bounced around I added some thin foam and made sure the battery could not move at all in the enclosure. I have a front mounted alternator on my 3.0. If I moved the alternator (dynamo) rearward using the SPA mounting system the battery could be further forward.
Dale
3.0 Corvair
Taildragger
Re: Trim system
Posted: Tue Aug 22, 2023 12:45 pm
by Panther16
My Sonex EW is 697, with D180, com, transponder, Garmin 296 and 2 Dynon A/P servos under seat pan.
Maybe Dale will share his empty weight. I do believe the Corvair is heavier than a 3300 Jab.
I am familiar with the Corvair as I have a 3300 Corvair in my Panther. I also set my GW at 1150.
Re: Trim system
Posted: Tue Aug 22, 2023 4:14 pm
by Tony4aro
Bryan Cotton wrote:Looks good Tony!
I had to make bushings to recess my PTT buttons, else my thumb hit the subpanel.
Also the Waiex will have a more aft CG than a heathen straight tail Sonex. I can’t get on my forward limit unless there is 17 gallons of fuel, a 98 lb pilot, and two helium balloons in the tailcone.
Regarding being stuck with the dial-a-trim, I really like mine. I can trim my full speed range from 60 kts to cruise. At full forward, my nose up spring/cable is slack. If I chucked a Corvair in my Waiex I bet I could shorten the cable and still have my full range.
I bet with the more aft CG of the Waiex that it may be the optimum Sonex airframe for a Corvair installation.
Thanks.
Now that you mention that the waiex will have an aft CG… I kind of forgot that we have that mixer back there adding tail weight.
Re: Trim system
Posted: Tue Aug 22, 2023 4:17 pm
by Tony4aro
daleandee wrote:My battery is as far back as it can go (I’ve looked for photos but can’t locate them now). Looking at the airplane from the left side the battery in located in the bay where the rudder cable exits and the access plate cutout is. I can reach the terminals by removing the access plate to attach a charger although I’ve never had to do that. It is mounted to a plate that is bolted to the bottom of the plane. It is a snug fit.
I built a small box for it and it’s held in place with all thread rod on each side with a Teflon top cover. Being in the tail and subject to being bounced around I added some thin foam and made sure the battery could not move at all in the enclosure. I have a front mounted alternator on my 3.0. If I moved the alternator (dynamo) rearward using the SPA mounting system the battery could be further forward.
Dale
3.0 Corvair
Taildragger
OK… I think you sent me pictures a year or so ago. I liked the install, but the Waiex has a mixer way back there, so I had no choice other than to move it forward.
Re: Trim system
Posted: Tue Aug 22, 2023 4:25 pm
by Tony4aro
Panther16 wrote:My Sonex EW is 697, with D180, com, transponder, Garmin 296 and 2 Dynon A/P servos under seat pan.
Maybe Dale will share his empty weight. I do believe the Corvair is heavier than a 3300 Jab.
I am familiar with the Corvair as I have a 3300 Corvair in my Panther. I also set my GW at 1150.
I think WW says it around 220 lbs installed. (Coils, wires, alternator, exhaust, oil) But I found an uncrating vid of a 3300, and they weighed it… it was just a touch over 190 lbs without the “Stuff”. So I’m really starting to think it’s a pretty close number when it’s all said an done.
Hey… by any chance did you hook your tach to the dynamo? WW had mentioned that someone did, and it was someone with a Panther. Right now, I have a pickup for my main tach… but my engine monitor can also run RPM, and I was thinking about hooking it to a second source for a real backup. I saw something that it’s just a 6 pulse/rev ac signal on the feed wires to the regulator.
Re: Trim system
Posted: Tue Aug 22, 2023 4:50 pm
by Panther16
On the Sonex the D180 haas 2 inputs for the tach. I take 1 off the left mag and the other off the Jabiru alternator.
On the Panther I have GRT 6 cylinder EIS and take the tach signal off the rear mounted SPA alternator.
Re: Trim system
Posted: Tue Aug 22, 2023 9:08 pm
by Tony4aro
Panther16 wrote:On the Sonex the D180 haas 2 inputs for the tach. I take 1 off the left mag and the other off the Jabiru alternator.
On the Panther I have GRT 6 cylinder EIS and take the tach signal off the rear mounted SPA alternator.
ok… great. I have the rear SPA alternator also. did you just hook the tach to one of the yellow wires? or is there something else inline?
Re: Trim system
Posted: Wed Aug 23, 2023 11:18 am
by Panther16
I checked W&B for both engines. Aerovee install empty weight 688. For Jabiru 3300 install 698.
As for tach may need a resistor in line, should be in instructions for instrument you are using. You have 50% chance of picking correct output lead of alternator, only 1 will work. If it doesn’t work switch to other output lead.
Re: Trim system
Posted: Wed Aug 23, 2023 5:06 pm
by Tony4aro
Panther16 wrote:As for tach may need a resistor in line, should be in instructions for instrument you are using. You have 50% chance of picking correct output lead of alternator, only 1 will work. If it doesn’t work switch to other output lead.
OK… thanks for the info.