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View Full Version : N7749D gets PA18 landing gear. Trimmer style.



captbill1956
08-08-2010, 11:52 PM
Just thought I would post these pics of the gear mod I am doing to my Tri Pacer.
The Trimmer gear mod is fairly labor intensive and requires making quite a few of the parts.
I started with the adapters that hook the bottom of the Maule oleo struts to the PA18 landing gear.
Only took 4 tries to get two good ones.
Now working on the Cabane V that goes between the gear legs and hooks up the upper end of the Maule
oleos.
All my welding is oxy acetylene.. RG65 filler rod. Using the little Meco torch from Tin Man. Works great.
Will try and keep this thread up as a log of the project. Hope you enjoy.
Bill Meredith
N7749D
Kingsland, TX

Stephen
08-08-2010, 11:55 PM
Thanks Bill...I like this option and love seeing it in detail.

captbill1956
08-08-2010, 11:59 PM
More pictues.

nicka
08-09-2010, 09:53 AM
Hey Bill, Keep the pics coming, I will be putting this gear on my fueselage when I get my wings finished.

Marty57
08-09-2010, 12:36 PM
Hi Bill,
Looks good, I have done many similar welds on my project. One suggestion that was given to me that I might pass along is regarding your vice. I have the same vice and the jaws are pretty sharp and rough on the surface of the material being held. It was suggested to me to make some covers for the jaws to avoid marring the surface. I took some mild steel and bent a couple of covers that I can remove when I need to hold something tight and surface marring is not a consideration or worry. Just thought I would pass that along, it made my work a lot cleaner and I had a lot fewer scratches to remove from my parts.
Marty57

Steve Pierce
08-09-2010, 05:27 PM
Awesome Bill. Thanks for the pictures and update.

captbill1956
08-17-2010, 01:49 AM
Here are pics of the forward landing gear attach fittings.

avcan
09-02-2010, 02:59 AM
Hi Bill.
Thanks for the photos. You look like you are doing a nice job! It's a rather big mod this isn't it??
I've just finished the mod on my Pacer - just recovering the fuse now. Only taken my the best part of a year, with work and family commitments etc etc :)
Some photos attached, that look very similar to yours! (I've tig welded mine).
Cheers
Craig

captbill1956
09-02-2010, 06:20 AM
Hi Bill.
Thanks for the photos. You look like you are doing a nice job! It's a rather big mod this isn't it??
I've just finished the mod on my Pacer - just recovering the fuse now. Only taken my the best part of a year, with work and family commitments etc etc :)
Some photos attached, that look very similar to yours! (I've tig welded mine).
Cheers
Craig

Craig,
Thanks for your photos. I hope you will post more. I am interested in seeing the fuselage work (cross tube changes, additions, left side vertical
tube change etc. Looks like you are an accomplished tig welder. I own a tig machine, but don't know how to use it, yet. I use the oxy act rig because I was trained on it many years ago in aviation mechanic school. Once again, please post more pics of your project. It really helps seeing how others have done it.........As you well know, a lot of the time on this project is just laying it out and figuring out what the drawings really mean.
Take care.
Bill Meredith
N7749D
Kingsland, TX

Bob
09-02-2010, 01:13 PM
Very nice posting, thanks for sharing.

avcan
09-05-2010, 04:51 AM
Hi Bill. I would love to take the credit for the welding but unfortunately I can't. My welding is ok, but for critical stuff, or where it needs to look good, I have a mate who is an expert!

Some more pics are attached... Hope they are helpful!

1. Fwd LH gear fitting and new fwd cross member (with 1 inch tube inside)
2. New fwd cross member, with lower fuse boot cowl former. Note the anchor nuts to attach the boot cowl - I hate self tapping screws!!
3. Lower fuse boot cowl former at centre junction.
4. LH longeron, and new support tubes.
5. New fwd cross member, showing gusset (larger than shown in Eddies pics)
6. New LH vertical frame tube at wing fitting. This was a lot of work. I cut the old tube below the wing fitting, and ground it all away inside, so the new tube could slide up snug inside the wing fitting, and then be welded in place.
7. Centre junction of new fwd cross member. This was also a lot of work, cutting away the original tube, and then grinding/filing so as to leave a snug fit for the new tube.
8. New support tubes. Also shows additional rear cross member installed. You can see on the longeron tube, some splices where I had to do some repairs, due to some damage I found in this tube.
9. Complete new RH cluster made, following our accident late last year.

MN_flyer1
09-05-2010, 09:29 AM
Avcan, How are things down there with the earth quake? I was pleased to hear that no one was killed.

Stephen
09-05-2010, 01:33 PM
Trimmer's mods are never under built.

avcan
09-05-2010, 02:15 PM
There is a lot of damage from Saturdays quake, but as you say MN_flyer1, it is amazing no one was hurt. The time of day (4.30am) had a lot to do with it - a few hours earlier and it would have been a different story I'm sure.
A lot of houses without water, power, and sewerage.
It was a bleak day for New Zealand because the same day, a skydiving aircraft (Walter powered Fletcher) crashed, killing 9 people including 4 tourists. Caught fire - not much left of it. Very sad.

captbill1956
09-05-2010, 04:54 PM
Craig,
Thanks for all the great pics. Very helpful and encouraging to see it done somewhere else.
Please keep us posted on the progress of your project.
Good luck with the project.
Bill Meredith
Kingsland, Texas
N7749D

Bob Mac
09-07-2010, 04:16 PM
From New Zealand and Texas come works of art that are truly humbling to some of us (at least to me) who think we know what we are doing!! I am envious and, needless to say, very imnpressed!
Bob

captbill1956
11-12-2010, 08:53 PM
Project Update: Oxy-Acetylene out. TIG in.

After much gnashing of teeth, and a few choice words thrown in, I elected to re make some of my parts using my Miller Econo-Tig. Another incentive was the nice looking welding that Avcan had on his project down in NZ.(also done with TIG) This was my first venture into TIG welding. I spent quite a bit of time practicing on scrap. I think my experience with oxyacetylene welding helped me progress fairly rapidly. I found that I was making superior looking welds and when destructively tested, held up MUCH better than the oxyacetylene welds.

The lesson I learned about oxyacetylene, is that the guys at Piper had a phenomenal amount of experience, and knew techniques that may have disappeared in history with them. When welding heavier stuff on the torch, it is really difficult to get a good bead and penetration without overheating and cooking or warping the part. I suspect they were using two torches on some of the stuff to provide some background heat and thus not overheating the weld area on the heavier fittings and such.

The TIG with its concentrated heat, does it easily, good penetration, excellent looking bead, and no warping. Anyway, will be posting some of my new stuff below.

I would really like to find one of the Piper welders from that era. Pick their brain on how some of this stuff was really done at the factory. May shoot an email to Clyde Smith and see if he knows of any of those guys still around.

Bill Meredith
N7749D
Kingsland, TX

captbill1956
11-12-2010, 09:05 PM
Here are some of the parts I re made and used the TIG on. The cabane V was jigged up by welding bolts to a 5/8 plate work table I have. Worked nicely keeping the holes where they belong.

nicka
11-13-2010, 10:24 AM
I have a question about this mod. What does the tube that the Maule Oleo struts are mounted in look like? Is it a streamline tube where it attaches to the gear? I was looking at an airplane here locally and it looked like it had streamline tubes for the oleo struts. If so could you use regular round tubing for the struts? There are a lot of airplanes here w/ homemade Cub gear, but they took the hydrasorbs and bungees and mounted them just like a Supercub, so they have done away with the weaker streamline tubes and replaced them w/ regular round tubing. Also are there provisions for mounting some check cables, or have you considered mounting some? I think Avcan there goes in and out of the rough stuff pretty regularly, Do you think you need them?

captbill1956
11-13-2010, 10:36 AM
"I have a question about this mod. What does the tube that the Maule Oleo struts are mounted in look like? Is it a streamline tube where it attaches to the gear? I was looking at an airplane here locally and it looked like it had streamline tubes for the oleo struts. If so could you use regular round tubing for the struts? "

Nick,
The upper end of the Maule strut bolts directly to the Cabane V. The bottom end is atached to an adapter fitting and
plugs right into the PA-18 3" Heavy Landing gear. As far as I can tell, the Maule Oleo strut is always in tension except
when the plane is flying. It is quite a heavy piece and doubt if there will be any issues with it. The fitting can be seen in the second picture Avcan posted (post #8 of this thread). All torsion loads will be handled by the heavy duty PA18 gear itself, the strut member having little to do other than keeping the gear from folding outwards under weight. It is not like a PA20 or PA22 welded tripod where the streamline tube absorbs the torsion loads from braking and rocks and oversize tires. Hope this helps answer your question.
Bill Meredith
N7749D
Kingsland, Texas

nicka
11-13-2010, 10:52 AM
Thanks for the response, that answers a few things. I know that it is frustrating to redo work, but the TIG welded parts look great and in the long run will be much better. What do you think of your Econotig? Also keep the pictures coming.

captbill1956
11-13-2010, 11:02 AM
Nick,
The Econotig is a fine welder. BUT, It does have one serious drawback for aircraft use.
The minimum amps is about 30.. This works ok on the heavier wall stuff, like .058 and above, but
will be too hot for doing any thin wall like .032. I am getting one of the new inverter based Miller Diversion 165
that has a minimum amp setting of 10. It seems to be a good bang for the buck and capable of welding down to
.020 or so. There are much more expensive machines that can go down to 1 to 5 amps.
I don't feel that capability justifies the cost difference for what I do. Plus, it's still made in USA!!
Will try and post some pics of the Maule strut when I get home in a few weeks so you can see what it looks like.
Bill Meredith
N7749D
Kingsland, TX

nicka
11-14-2010, 01:27 PM
Hey captbill1956, another question what does the STC have for wheels and brakes setup, it uses cub gear so are they some kind of cub setup?

captbill1956
11-14-2010, 01:47 PM
The STC calls out Cleveland 199-060, 199-062, or 199-062A wheels and brakes. In the cockpit, any STC differential brakes, or factory brakes (pa20 or pa16) or his own set up as part of the STC. Pretty liberal for the most part.

captbill1956
08-25-2011, 09:41 PM
It has been an extraordinarily hot summer in central Texas. Due to the weather and family obligations, progress has been slow on the conversion. But there HAS been progress, just not a lot.....;-)
Here are a few pics that show the thing sitting up on the gear now. Got the 8.50 x 6 mounted and a comparison pic with
a 6.00 x 6 beside it. Enjoy.

avcan
08-26-2011, 05:10 AM
Well done. Good to see progress!! How did you get on getting the wheel alignment set up? Did you set it neutral, or slightly toe in?
Craig

captbill1956
08-26-2011, 08:02 AM
Craig,
I set the thing to neutral with the aircraft level.
I used a 3 inch square, 3/16" wall tube about 10 foot long with some
brackets I fabricated for the axles. Very similar to what was shown in
the STC manual. Was tough to get it all lined up and square and all that.
Its welded now, so will be what ever it will be.

How is your bird doing? Haven't seen any more pics of it with the new gear on it.
Are you happy with the mod? Any comments on way or another??
Thanks for the "well done"

Bill
N7749D
Kingsland, TX

Bob
08-26-2011, 10:00 AM
I am envious of people who take on such projects. It is the only way our antiques stay flying. If we had to pay for the true investment, they'd be worth 10x as much. Nice work.

jay heil
08-26-2011, 12:20 PM
if anyone is looking for a tig welder I bought this one I had to pay the 899 for it it works great theres a couple things I would like differant ,like an ammeter and adj ac freq but then again I wanted a tig for so many years and it just had to be a ac-dc square wave so I bought this and have had it close to 6 months and have yet to have the need to weld aluminum even though I now could if I wanted anyway the things now on sale for 699 thats crazy but if anyone is looking I dont know where you will get somthing better for that kind of money http://www.eastwood.com/eastwood-s-ac-dc-tig-200-welder.html

Curly
08-26-2011, 06:57 PM
Jay - This is the unit I have decided on - sold here under at least 3 different brand names but all exactly the same machine out of China (naturally). Prices range from around $AUD750 to $1400 depending on who is selling it and what name is on the outer case. One company sells at least 3 a week on ebay for anywhere from $AUD750 - $900. (and when I was selling retail, I would have given my left tes.... to be able to sell 3 tigs a week). Reliability does not appear to be an issue, spare parts are available and cheap, and those people I have been able to contact are very happy with the unit.
http://www.ebay.com/itm/200-Amp-Ac-Dc-Pulse-Tig-Stick-Welder-Arc-Aluminium-/260714213281?pt=BI_Welders&hash=item3cb3c72fa1

jay heil
08-26-2011, 08:08 PM
wow thats probably even better than the other one Im happy with mine but now there selling it for 699 the one you got there is alot more features looks like a great welder

DEW
01-29-2013, 04:30 PM
avcan...can you tell me the wall thickness on the rear gear fitting cross member.

Thanks
Dennis

avcan
01-30-2013, 01:42 AM
0.875 dia x 0.058 wall thickness.
Craig

DEW
02-05-2013, 12:28 PM
On the trimmer gear mod drawing does it require replacement of the tube from the new forward gear fitting all the way to the forward wing root fitting? I would be willing to buy someones drawings for the fuselage beef up I don't need the STC I'm EXP.

Steve Pierce
02-05-2013, 12:52 PM
Dennis, Call Eddie and talk to him. I bet he will sell you the drawing cheap. Just don't tell him your associated with Jr. 8) It does require changing that tube. The geometry is totally different with the Cub gear.

DEW
02-05-2013, 02:50 PM
Does he live on the same strip as Jr. I might have already met him. Thanks Steve I'll call him.

DEW
02-10-2013, 11:52 AM
haven't been able to get a response from Eddy so I have another question...do you need to replace the carry through spar between the front gear fittings...wall thickness ??...and do you replace the 3/4" tubes from the gear fitting to the wing fitting...again wall thickness??? thanks for any help.

DEW