Trim system

[Tony4aro]

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.

[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.

[daleandee]

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

[daleandee]

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~)

[daleandee]

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

[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.

[Tony4aro]

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.

[Tony4aro]

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.

[Tony4aro]

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.

[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.