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Elevator Trim systems

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7suds(at)Chartermi.net
Guest

Posted: Mon Jan 02, 2006 8:01 pm Post subject: Elevator Trim systems



All,

I am reworking a Model 5 that originally had the Electric Elevator Trim

Screw. I was intending on changing it to the trim tabs on the elevator and

replacing the Electric ElevatorTrim Screw with the hard link similar to the

retro kit that Skyster was offering. I was recently challenged on that

thought and was wondering what those of you out there flying either the

adjustable horizontal stab, the elevator trim tabs or both feel about the

subject? Which do you like and why?

Thanks,

Lloyd

aldaniels(at)fmtc.com
Guest

Posted: Mon Jan 02, 2006 9:38 pm Post subject: Elevator Trim systems



I have built and flown both. Both are good, the manual system is faster

to set for touch and go's, the electric is a little easier to fine tune

to hold altitude. The manual also is much heavier on the stick while in

the flair and on the ground, unless of course you use John McBeans super

system. The best is IMHO the electric with an oversized elevator, but I

like to be able to roll the tailwheel before the mains touch, even with

big tires. The down side is that at that AOA the wing will really pay

off and drop you so if you are a little high when that happens you drop

it in. I got a set of VG I am wanting to try to see if that helps, but

even if you drop it in if you hold the stick back you are down safe and

short.

Cudnohufsky's wrote:

All,

I am reworking a Model 5 that originally had the Electric Elevator Trim

Screw. I was intending on changing it to the trim tabs on the elevator and

replacing the Electric ElevatorTrim Screw with the hard link similar to the

retro kit that Skyster was offering. I was recently challenged on that

thought and was wondering what those of you out there flying either the

adjustable horizontal stab, the elevator trim tabs or both feel about the

subject? Which do you like and why?

Thanks,

Lloyd

morid(at)northland.lib.mi
Guest

Posted: Tue Jan 03, 2006 4:49 am Post subject: Elevator Trim systems



Why do you want to remove the trim screw Lloyd? Although there may be

others, I can only recall one failure that caused any sort of problem.

Deke

 	  Quote: 	
		   All,

I am reworking a Model 5 that originally had the Electric Elevator Trim

Screw. I was intending on changing it to the trim tabs on the elevator and

replacing the Electric ElevatorTrim Screw with the hard link similar to

the 	


 	  Quote: 	
		   retro kit that Skyster was offering. I was recently challenged on that

thought and was wondering what those of you out there flying either the

adjustable horizontal stab, the elevator trim tabs or both feel about the

subject? Which do you like and why?

Thanks,

Lloyd

n981ms(at)yahoo.com
Guest

Posted: Tue Jan 03, 2006 5:28 am Post subject: Elevator Trim systems



I have only flown the electric on a Model 5 and 6. I like it fine. No real problem in the pattern. It could use a little more up trim for use with flaps. It is very sensitive at cruise speed but that could be altered with Matt Dralle's Governor. If you decide to go with the manual I would be interested in buying you linear actuator.

AMuller589(at)aol.com
Guest

Posted: Tue Jan 03, 2006 1:18 pm Post subject: Elevator Trim systems



Our trim brushes wore out at 60 hours but found a place in Conroe, TX who

replaced for $16. They are sensitive at cruise and not quite adequate for full

flaps but are all around O.K. We think we would prefer mechanical though never

tried them for comparison.

7suds(at)Chartermi.net
Guest

Posted: Wed Jan 04, 2006 4:31 pm Post subject: Elevator Trim systems



Deke,

The screw was destroyed by the previous owner in a ground loop incident, in

rebuilding I was pondering 2 thoughts, ONE, I fit the Model 4 I previously

had with an elevator trim tab operated by a push pull cable to a lever I

mounted just in front of my flap lever, it was fast and easy to adjust and I

could trim for landing by feeling the position of the lever against the

center bar, no need to look, it was also very easy and fast to trim for

hands off flying, I liked it. TWO, some time after Skystar made the Model 5

they offered a retro kit to replace the screw with trim tabs, why would they

offer the retro kit if the screws were so well liked? Since I would have to

replace the screw to stay with that system I was thinking I may want to move

to the trim tab option. (Which I know I like, it's fast to trim, and it's

simple) I would hate to spend the money on a new screw and find I am not

satisfied with the response or ergonomics of the system. That's my dilemma.

Lloyd

7suds(at)Chartermi.net
Guest

Posted: Wed Jan 04, 2006 4:34 pm Post subject: Elevator Trim systems



Maxwell,

Screw was destroyed in a ground loop incident by previous owner.

Lloyd

wingsdown(at)comcast.net
Guest

Posted: Wed Jan 04, 2006 6:23 pm Post subject: Elevator Trim systems



FYI, I have a complete flight control system to include the jackscrew

assembly and all parts forward and aft required to use it. Other Model 5

parts as well.

Rick

lcfitt(at)sbcglobal.net
Guest

Posted: Wed Jan 04, 2006 6:39 pm Post subject: Elevator Trim systems



some time after Skystar made the Model 5

 	  Quote: 	
		   they offered a retro kit to replace the screw with trim tabs, why would

they

offer the retro kit if the screws were so well liked? >>>

	


I think they changed the system because the manufacturer of the jack screw

didn't like them being used in Aircraft. I may be wrong in this, but in

talking to the guys flying them, I think they generally like them fine.

Lowell

wingsdown(at)comcast.net
Guest

Posted: Wed Jan 04, 2006 8:46 pm Post subject: Elevator Trim systems



I few many hours with the electric system. I think it was a cost driven

move to the mechanical set up.

Rick

bnn(at)nethere.com
Guest

Posted: Wed Jan 04, 2006 10:07 pm Post subject: Elevator Trim systems



At 04:46 PM 1/4/2006, you wrote:

 	  Quote: 	
		   I fit the Model 4 I previously

had with an elevator trim tab operated by a push pull cable to a lever I

mounted just in front of my flap lever, it was fast and easy to adjust and I

could trim for landing by feeling the position of the lever against the

center bar, no need to look, it was also very easy and fast to trim for

hands off flying, I liked it.

	


LLoyd,

What did you use for the cable and tab? How did you do the tab end

of things? I'm agonizing over the same thing on my IV with completed elevator.

Thanks,

Guy Buchanan

K-IV 1200 / 582 / 99.9% done, thanks mostly to Bob Ducar.

Ceashman(at)aol.com
Guest

Posted: Thu Jan 05, 2006 3:31 am Post subject: Elevator Trim systems



 	  Quote: 	
		  LLoyd,

What did you use for the cable and tab? How did you do the tab end 	


 	  Quote: 	
		  of things? I'm agonizing over the same thing on my IV with completed

elevator. 	


 	  Quote: 	
		  Thanks,

Guy Buchanan

	


Guy. A long time ago I visited Skystar and had a flight in their IV I believe

it had the 618

engine.

Anyway, that aircraft was fitted with a RANS trim system (the guys at SS told

me that).

When building my IV, I purchased the RANS trim system from Aircraft Spruce (I

cannot find it in the AS catalogue right now). It was not that difficult to

install but I had to make a bracket to hold the spin wheel that I could screw

to the floor.

Look at the trim at this link.

Greetings. Eric.

http://www.shoprans.com/AccessoriesAircraft.htm

7suds(at)Chartermi.net
Guest

Posted: Thu Jan 05, 2006 5:53 pm Post subject: Elevator Trim systems



Guy,

The trim on my 4 was an after thought so I made a trim tab from light gauge

aluminum, about 14 ga. it was about 3.5" x 20" and was attached to the

trailing edge of the elevator with a piano hinge via SS pop rivets. The

cable was a single solid push pull wire in a wire would casing, very similar

to what is used on lawnmowers etc. but a little heavier. I purchased mine at

a hardware store. For the lever in the cockpit I fabbed out of aluminum flat

stock and made a friction system similar to the flap handle friction system

in the earlier Kitfox's To attach the push pull wire to the handle I made a

swivel fitting from a small piece of aluminum square stock, drilling a hole

in the end to accept the push pull cable and 2 holes at 90 degrees drilled

and tapped for set screws to lock it in. A 3/16" cross hole was drilled at

the other end to bolt it to the handle. Fabricated a holder for the wires

sheath just in front of that, I think the other end was similar. The cable

was run through the fuselage and exited below the horizontal stab at the

rear. 2 stand-off horns were fabbed from aluminum, one was riveted to the

trim tab and the other to the cross bar in the elevator.

Lloyd

bnn(at)nethere.com
Guest

Posted: Thu Jan 05, 2006 8:08 pm Post subject: Elevator Trim systems

`At 06:08 PM 1/5/2006, you wrote: Guy, The trim on my 4 was an after thought so I made a trim tab from light gauge aluminum, about 14 ga. it was about 3.5" x 20"`

What did you think of the size. Was it about right? Too large? Too small?

Quote:

stock and made a friction system similar to the flap handle friction system

How did the friction system work? I bought a small throttle quadrant that
uses friction but I was worried it wouldn't hold.
...

Quote:

The cable
was run through the fuselage and exited below the horizontal stab at the
rear. 2 stand-off horns were fabbed from aluminum, one was riveted to the
trim tab and the other to the cross bar in the elevator.

Did you run the cable out the angled member of the elevator? Or did the
cable make some kind of an "S" to meet the tab perpendicular to it?
Thanks for the help. By the way, I got your sketch off-line and it
clarified how you handled the back end. Thanks again.
Guy Buchanan
K-IV 1200 / 582 / 99.9% done, thanks mostly to Bob Ducar.

7suds(at)Chartermi.net
Guest

Posted: Fri Jan 06, 2006 2:02 pm Post subject: Elevator Trim systems



Guy,

The trim tab size was correct for my 4, however it was an XL Model with a

gross of 950 and a VNE of 104mph. I was running a 503 that would cruise

around 70 and it worked great. I know Al has now installed a 582 and as far

as I know he is still using the same trim system. The friction system on the

handle worked great as well, I never had it slip on me. Another thought is

what the RV guys are running, they are using a push pull very similar to a

throttle, has a push button on the end to lock / unlock and make large

adjustments and can also twist from the lock position for micro adjust. Have

never talked to anyone about how well they like it. I ran the cable out from

the fuselage just under the horizontal stabilizer at about 1/2 the chord.

The trim tab was close to the rudder side of the elevator and the stand-off

was off set to line up with the structural tube in the elevator. Cable

stayed close to the bottom of the horizontal stab and did have a bit of an

"S" shape to it. I also put O-Rings on the cable to keep it from chaffing

the fabric / finish.

Lloyd

jdmcbean(at)cableone.net
Guest

Posted: Fri Jan 06, 2006 6:26 pm Post subject: Elevator Trim systems



Lloyd,

As with anything I'm sure opinions will vary.. and both trims have pros and

cons...... I'll stick with the screw jack over the offered manual trim. If

someone wants the manual trim that SS was offering I know of one available..

Cannot guarantee all the parts were delivered.

Regarding the screw jack.. If memory serves me there were 3 different

actuators..

To the best of my knowledge, and I have looked in to this... there was one

failure. I do not recall which model actuator but I believe it was an

earlier model.

Skystar changed to the manual trim for 2 reasons:

1 The manual system was a commonly asked for item - Could it be an option ?

2 Motion Systems stopped selling them to Skystar.. supposedly because they

were going on aircraft.

I have looked into replacements and can most likely get them.. However, I

was very cautious not to let them know they were going on aircraft.....

Have a Safe New Year !!

John McBean

www.sportplanellc.com

"The Sky is not the Limit... It's a Playground"

bnn(at)nethere.com
Guest

Posted: Sat Jan 07, 2006 7:55 am Post subject: Elevator Trim systems



At 02:16 PM 1/6/2006, you wrote:

 	  Quote: 	
		  Another thought is

what the RV guys are running, they are using a push pull very similar to a

throttle, has a push button on the end to lock / unlock and make large

adjustments and can also twist from the lock position for micro adjust.

	


Thanks Lloyd,

I've seen this system and though it looks great in an RV, it's a

bit large for a IV. I've already got the friction lever installed so I'm

happy to hear it worked for you. Thanks again for all the help.

Guy Buchanan

K-IV 1200 / 582 / 99.9% done, thanks mostly to Bob Ducar.

Do not archive

foxfloatflyer(at)hotmail.
Guest

Posted: Mon Jan 09, 2006 8:09 am Post subject: Elevator Trim systems



I have added a photo to the sportflight.com photo share under damage/incidents of a failed Pittman style electric trim actuator. This failure occurred during the installation process when I tried to nudge the actuator into position. I have since obtained a Warner actuator (the type with a reported in-flight failure) and have added a reinforcing bracket at the failure point. Failure analysis indicates that a lateral load of only a few degrees can cause either of these actuators to fail this way. Lesson learned: Make sure things line up before installing the actuator and remember this isn't plumbing your doing.

Joel

smokey_bear_40220(at)yaho
Guest

Posted: Mon Jan 09, 2006 9:47 am Post subject: Elevator Trim systems



Thanks for the heads up Joel,

I think you learned this lesson the cheap way, even

though it cost you $, only the actuator broke and not

you and your plane. 

I wonder if this lateral loading was the real problem

in previous failures?

Kurt S. S-5/NSI turbo

--- Joel Mapes <foxfloatflyer(at)hotmail.com> wrote:

 	  Quote: 	
		   I have added a photo to the sportflight.com photo

share under damage/incidents of a failed Pittman

style electric trim actuator. This failure occurred

during the installation process when I tried to

nudge the actuator into position. I have since

obtained a Warner actuator (the type with a reported

in-flight failure) and have added a reinforcing

bracket at the failure point. Failure analysis

indicates that a lateral load of only a few degrees

can cause either of these actuators to fail this

way. Lesson learned: Make sure things line up before

installing the actuator and remember this isn't

plumbing your doing.

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