Trim system and header tank

[Bandit 286]

Here is my trim system. Total cost 50 cents. No sense for a complicated trim system. This is how my header tank is plumbed. A header tank is no different than a big piece of gas line. No reason to vent it. The gas caps do have to be vented though.

[EDMO 1078]

Bandit,

Can you explain your trim system? I am totally in the dark about the complex controls of both the Avids and Kitfoxes.

I am guessing that this 50-cent spring takes the pressure off of your control stick when you pull flaps on, the same thing that complicated and expensive trim tabs and associated cables, servos, with the added drag, are supposed to do -

KISS at its best!

Thanks,

EDMO

Edited 16 Mar 2015 by Ed In Missouri

[Bandit 286]

The spring is connected to the trim control not the flaperons. I can only get up trim with this system. To get down trim I use the flaperons. It doesn't take much. Yes, the trim lever and spring pull the elevator to the up position, just like a elevator trim tab, but much simpler.

[EDMO 1078]

The spring is connected to the trim control not the flaperons. I can only get up trim with this system. To get down trim I use the flaperons. It doesn't take much. Yes, the trim lever and spring pull the elevator to the up position, just like a elevator trim tab, but much simpler.

My Kitfox has a similar spring connected to the elevator tube - I figured it was in case a bolt breaks, the elevator would be sprung to an up position - guess it makes stick force lighter too.

I have seen trim tab drawings with a spring attached - if a cable breaks, the spring pulls the tab down which brings the elevator up.

EDMo

Edited 16 Mar 2015 by Ed In Missouri

[1avidflyer 1983]

Hey Bandit, I like the simple trim system you have.  I've looped  a 1/4" bungee around the seat truss and the joystick.  Pulling the bungee up the stick stretched the bungee which pulled the stick back.  I do like yours though.  As far as the header tank vent goes, I would say you have one with the push drain on the top of it.  Once you let the air out it should stay out unless you run out of gas.   I had a valve on my vent line, and would vent the header tank in preflight, and then close the valve.  Jim Chuk

PS  Just looked again at your picture, do you have anything stopping the joy sticks from going so far forward that the elevator push-pull tube touches the cross tube and causes a bending action on the elevator control tube/ heim joint?  I'm sure there was an AD on that.

Edited 16 Mar 2015 by Jim Chuk

[dholly 718]

Here's the Aerotrek bungee trim assist 'system'.

[FoxDB 17]

I installed the Aeroconversions Trim system. Not 50 cents though $100 but it works good and is not difficult to install.

[RDavidson 183]

My Magnum header tanks do not have a vent line of any type. Should I put a vent line or top drain, like depicted above, in the top of my header tanks?

Thanks,

Ron

[Luked 71]

Hey Bandit,

 

Looks good, and it sure is simple. Even the legendary Pappy Boyington didn't need a fancy trim system in his Corsair:

 

 

 

"I used to envy the bomber pilots, who had automatic pilots in their planes. So, for lack of an automatic, I would take along rubber bands and pieces of string, and I would rig these up on the instrument panel and on the brackets on the side of the cockpit, and I would have them all fixed up so that I could sleep most of the way going up to enemy territory. I would loosen my safety belt and half crawl out of my parachute straps, and then I would doze off.

"Rarely would I have to glance at the altimeter, for I was able to tell by the sound of my engine whether I was going up- or downhill. So, without opening my eyes, I would just reach out and tap the rear string, and everything would sound right and I could doze off again.

"If one wing dropped, I would lurch over to that side, gently tap the rubber band, and when the adjustment was made and I was sitting on an even keel, I would doze off once more."

 

Here's the rest of the article:

 

http://unclemikey.blogspot.com/2004/09/greg-boyington-crazy-sob_24.html

[dholly 718]

If you want to get real creative, here is a pic I took at Osh'14 of the trim system in a Carbon Cub.

[wolves200 31]

well; that´s the simplest trim I ever seen; I will install one in mine, I´m not a good fan of trim systems, because the complicated installation.

[KFfan 151]

Please excuse my ignorance;

Is that looking forward from the rear of the stabalizer & leading edge of the elevator?

[dholly 718]

Sorry, pic was on my phone. Rotate 90* right, view is from rear looking forward. The dark is fuse and light is horiz. stab. framing. Can only see the elevator and trim attach tab, not the elevator itself. Personally, I get nervous at the thought of springs or cables or pulleys ie., anything hard, breaking and jamming up something critical. That's why I like the Aerotrek trim assist. Bungee breaks and not much chance of jamming the controls.

[Luked 71]

That's an interesting system. The yoke connected to the leading edge of the HS looks pretty much like other cub setups I've seen, but they added a spring tensioner to put some up elevator pressure on the control system. Do other cubs have the spring biasing system like this?

[EDMO 1078]

I have seen this in other homebuilder books - Tony Bingeliss author?

EDMO

Edited 19 Mar 2015 by Ed In Missouri

[EDMO 1078]

If you want to get real creative, here is a pic I took at Osh'14 of the trim system in a Carbon Cub.

Doug,

If I am seeing this right, the spring is connected to a cable which runs thru a pulley and connects to the up elevator cable - and if a bolt or el-cable breaks, the spring no longer will have any force on it to bring the elevator up? Maybe?

I think the one I saw was hooked to a solid part.

EDMO

Edited 20 Mar 2015 by Ed In Missouri

[Luked 71]

Ed, I think the other end of that cable is connected to the HS yoke, so when you dial in UP trim, the yoke goes down, and pulls a little on the cable and the spring giving you a  little up elevator also.

[EDMO 1078]

Ed, I think the other end of that cable is connected to the HS yoke, so when you dial in UP trim, the yoke goes down, and pulls a little on the cable and the spring giving you a  little up elevator also.

Thanks Luke,

I have seen other Pipers with interconnected springs and cables.

EDMO

[dholly 718]

Ed - there are a couple pics of the elevator trim assist and elec H.S. jack screw in the CarbonCub parts catalog (chapter 27) that might help better visualize them. http://www.cubcrafters.com/pdfs/ccss/cc11-160_parts-catalog.pdf

[EDMO 1078]

Kool Doug,

Your extensive library is a gold mine for us!

Thanks,

EDMO

[dholly 718]

Just fallout from research for my CarbonSuperAvid+

[EDMO 1078]

Just fallout from research for my CarbonSuperAvid+

Is that now going to be, "CarbonSuperAvidMAGNUM"?

EDMO

[dholly 718]

I might have been able to justify swinging down to 'Misery' on my pilgrimage to OSH this year if you could go grab and hold it for me. Unfortunately, RT to Pueblo is 50+ hours and 3600 mi. from me, quite a bit longer than my weekend 'Ironbutt' run to pickup the Aerotrek in TX. Ughh, even if my back wasn't an issue at the moment... getting too old for that!

 

[edit] Ever since the war effort drank the JetA and EPA refinery regs sent diesel prices to the moon, trying to find reasonably priced X-country transport options has been tough. Then again, that stoopid 'Shipping Wars' show didn't help much either...

Edited 22 Mar 2015 by dholly