Looking for correct drawings for AWB 2500 Skis

A place to relax and discuss flying topics.

Moderators: GAHorn, Karl Towle, Bruce Fenstermacher

hilltop170
Posts: 3481
Joined: Sat May 06, 2006 6:05 pm

Re: Looking for correct drawings for AWB 2500 Skis

Post by hilltop170 »

mdpesky wrote:".............The old original cables are an odd size of 5/32", a special order size by most suppliers. Does anyone know if its OK to up-size to the more common and stronger 3/16" cable size for the rigging?

Any advice on this will be greatly appreciated..............
Mark
Mark-
I think my cables are 1/8" but to be sure, call Atlee Dodge Aircraft in Anchorage and talk to Steve Kracke. He will give you the correct info. They also rebuild and set up AWB2500s regularly. Steve knows as much about them as anybody. At the speed 170s fly, 3/16 " cable sounds like overkill. Don't believe anything Kracke says about me.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
User avatar
mdpesky
Posts: 46
Joined: Wed Mar 15, 2006 7:45 pm

Re: Looking for correct drawings for AWB 2500 Skis

Post by mdpesky »

Hi Richard

I called Steve as you advised and he said its OK to go with the larger 3/16" cable in either galvanized or Stainless(if operating near salt water).

Based on that we decided to go with the 3/16" in stainless, even though we're not in salt water area, the stainless will look better longer and yields a much higher strength then the 5/32" galvanized does.

Now my latest problem, these ski’s have what appears to be the stock Federal rigging that went to the bottom engine mount with a 9/16” size bungee which measures along its inside diameter 16 1/4” long. I’m not sure on the correct math to calculate what the actual diameter would work out too, but my rough measurements across the circle are 5 1/4” (it takes a very slight stretch to fit it over a round 5 1/2” pipe).

The closest bungee I could find was from Aircraft Spruce measuring 4 1/2” diameter but this is too tight, they don’t fit??

Being also they are for ski application, I believe I need a cold weather(CW) version(not sure?)?

Now I'm having trouble sourcing the 9/16" x 5 1/4" bungee, again I've tried the usual suppliers, but this size doesn't match anyones charts????

I reach out again to the group for advice and direction!

Mark
MDPesky:1954 C-170B/C145/Horton Stol, 1960 C-182C/520ci/Sportsman/Vortex/Wing-X/Alaskan Bush Wheel/Atlee Dodge/Ext-bag/Belly-Pod, 2013 Zenair CH750/912iS, 1999 Europa Tri-Gear/914 Turbo
User avatar
ddr36d
Posts: 25
Joined: Tue Oct 18, 2005 1:36 am

Re: Looking for correct drawings for AWB 2500 Skis

Post by ddr36d »

Mark,
Contact SBC Industries in Scottsboro, AL. They are the manufacturer of shock cord rings. http://www.sbcindustries.com
Yes, you will want the cold weather part #. The rings on my Fly-lite 3000's are p/n 70144-CW.
Don
User avatar
mdpesky
Posts: 46
Joined: Wed Mar 15, 2006 7:45 pm

Re: Looking for correct drawings for AWB 2500 Skis

Post by mdpesky »

I reach out again to the group in another act of desperation!

We just realized that the drawings call for spacers over the axle bolts to go between the inner ski axle face plate and the rigger arm. The drawings specify Federal part number 11A890-2 and 11A890-1(4 each) but do not give any size dimensions especially the width(thickness) for these spacers? It should be safe to conclude that the I.D. is the same as the axle bolts size which is 5/16" and 3/8", an educated guess for the O.D. is simple enough, but we have no clue as to how wide(thick) these spacers should be?

Assuming these Federal part numbered spacers will be as elusive to find as the Federal rigger arms and NAS axle bolts, we may be forced to machine new ones(here we go again), can anyone tell me how wide these spacers should be? Does anyone by chance have a spare set, 4 of the Federal part number 11A890-2 and 4 of the 11A890-1?

John, would it be possible to get you to measure how wide yours are? If you could also supply an O.D measurement that would be great, better yet, how about you sell me yours :D

Next time I buy ski's I will happily pay double if they come with all the plumbing, rigging everything ready to install, plug and play, that would be a bargain!!! 8O

Mark
MDPesky:1954 C-170B/C145/Horton Stol, 1960 C-182C/520ci/Sportsman/Vortex/Wing-X/Alaskan Bush Wheel/Atlee Dodge/Ext-bag/Belly-Pod, 2013 Zenair CH750/912iS, 1999 Europa Tri-Gear/914 Turbo
hilltop170
Posts: 3481
Joined: Sat May 06, 2006 6:05 pm

Re: Looking for correct drawings for AWB 2500 Skis

Post by hilltop170 »

Mark-
If you have to make them, the spacers will be of a width so that the positioner arm lines up the positioner parallel to the longitudinal ski axis, it should be easy to measure with the skis retracted and in position on the stub axle.

Another thought, if your wheel axles have tapered shim wedges to align the wheels, you might think about placing a reverse set of shim wedges on the stub axle to line up the skis with the wheels.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
stogie17
Posts: 28
Joined: Mon Dec 02, 2013 7:23 pm

Re: Looking for correct drawings for AWB 2500 Skis

Post by stogie17 »

I have 8.50X6" Goodyears on my 170B with Awb 2500's ok have been told smaller would be better and my 26X10.5X6" won't fit.
User avatar
JohnNielsen
Posts: 102
Joined: Tue Sep 14, 2010 10:21 pm

Re: Looking for correct drawings for AWB 2500 Skis

Post by JohnNielsen »

http://youtu.be/Qhuj5ig6hJ4

I got mine installed and tested. They work great...but temps soared into the 40s and snow turned to slush :(.

These are vid clips of the operation up and down.

http://youtu.be/yo7W_8sMGoE

The hyd lines are 1/4" stainless braided and yes, I insulated contact areas with Teflon tape along the attach runs of the gear legs.

Now we need some cold temps and snow!!
hilltop170
Posts: 3481
Joined: Sat May 06, 2006 6:05 pm

Re: Looking for correct drawings for AWB 2500 Skis

Post by hilltop170 »

John-
That's a nice looking set of skiis! As you can see in the videos, the check cables are slack the entire time and only get tight when the ski reaches it's travel limit, the bungees really don't do anything.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
User avatar
mdpesky
Posts: 46
Joined: Wed Mar 15, 2006 7:45 pm

Re: Looking for correct drawings for AWB 2500 Skis

Post by mdpesky »

John, what size are your tires that you show in your video? I see the clearance with skis down(wheels up) between the tire and the ground is minimal, is this why they say smaller tires would work better as they give less drag when skis are down in snow?

I ordered today a new set of 8:50's for mine, hoping that was the right move? My thoughts were they would give me better clearance when on wheels(skis up) to lift the skis away from the muck and potholes when landing on less then desirable wet spring time gravel/grass runways etc.?

Also after looking all over kingdom come for the axle bolts as per the drawings we finally got them only to find now they are too long! Even though the drawings clearly list these as the right bolts for both the C180 & C170, is it possible the C180 has a thicker axle flange and/or gear leg that would take up this extra space?

I have the solid aluminum ski axles on my tire side(outer), and the correct Federal axles(I assume) for the inner side, so what is different that the bolts end up too long?

Anyways, we now need to build a good 1/4' thick spacer and use a lot of washers to make it all fit and line up with these longer bolts, not sure how we got sideways with this latest issue???

Next question, I just bought a McCauley Sea Plane 80/42 prop, will my old spinner fit onto this longer DM prop, my old prop was also a DM series(not MDM)?

Last question, I see John's installation only runs the front cables/bungies to the bottom engine mount as per the drawings. Steve at Atlee Dodge told me its much better to run straight safety cables to the bottom engine mount and a second cable with bungee to the upper fuselage just rear of the top engine mount. Searching the net and this forum I see it done both ways. Any opinions on this, my skis are already rigged to go to just the bottom engine mount, now we're getting ready to re-rig it all as per Steves advice????

One final heads up to everyone in general. Originally I had Aero 2000 ski's on the plane and had flown it approx. 500 hrs. of ski flying, some times in pretty rough conditions. When we removed the axles we found a slight shear stressor on the old left side axle bolts. That was a shocker but after thinking about it those axles really take a beating some times. It might be a good idea each annual if your going on ski's to pull those bolts and check them, sure glad I discovered mine were stressing out in time!

As always, thanks for any advice guys, hopefully we get through this yet??
MDPesky:1954 C-170B/C145/Horton Stol, 1960 C-182C/520ci/Sportsman/Vortex/Wing-X/Alaskan Bush Wheel/Atlee Dodge/Ext-bag/Belly-Pod, 2013 Zenair CH750/912iS, 1999 Europa Tri-Gear/914 Turbo
User avatar
mdpesky
Posts: 46
Joined: Wed Mar 15, 2006 7:45 pm

Re: Looking for correct drawings for AWB 2500 Skis

Post by mdpesky »

And the group falls silent, have I finally stumped them????
MDPesky:1954 C-170B/C145/Horton Stol, 1960 C-182C/520ci/Sportsman/Vortex/Wing-X/Alaskan Bush Wheel/Atlee Dodge/Ext-bag/Belly-Pod, 2013 Zenair CH750/912iS, 1999 Europa Tri-Gear/914 Turbo
User avatar
mdpesky
Posts: 46
Joined: Wed Mar 15, 2006 7:45 pm

Re: Looking for correct drawings for AWB 2500 Skis

Post by mdpesky »

Hi Group

I’m wondering if anyone could give me some comments from their experiences if this Ski Install looks right?

We’ve installed the AWB2500 Ski’s on my C170B in accordance to the drawings which call for approx. +2.5 degrees ski nose up when ski is in down position, and approx. –5 degrees ski nose down when the ski is in the up position.

With are rigger arms screwed all the way in, the best we could get ours set to was +2.2 degrees when skis are in the down position and –8 degrees when the ski’s are in the up position.

Our rigger arms are correct according to the drawings as is all other parts and pieces(as far as we can tell).

Do you think this is OK and in a suitable range?

It looks dead right when the ski is in the down position, but looks to us like the ski is nose low when in the up position aircraft level flight(see photos)?

I’m having a hard time believing in level flight with Ski’s up we would be flying with the nose of the ski –8 degrees dragging in the wind? Obviously it would have less drag when the ski is in the down position(+2.2 degrees), is it normal that people would cruise with ski’s down to go faster?

Does the –8 degrees down look unusual to anyone with any experience installing these(see pictures)?

Any advice will be greatly appreciated, we’re trying to get this thing finished and keep running into these hurtles.
Attachments
20141128_180525[1].jpg
20141128_180451[1].jpg
MDPesky:1954 C-170B/C145/Horton Stol, 1960 C-182C/520ci/Sportsman/Vortex/Wing-X/Alaskan Bush Wheel/Atlee Dodge/Ext-bag/Belly-Pod, 2013 Zenair CH750/912iS, 1999 Europa Tri-Gear/914 Turbo
hilltop170
Posts: 3481
Joined: Sat May 06, 2006 6:05 pm

Re: Looking for correct drawings for AWB 2500 Skis

Post by hilltop170 »

Mark-
From what I remember when I installed mine back in about 1991, the hole in your rigger arm may need to be moved to get the exact up and down ski angles. Remember, those rigger arms were made for the L-19 with different gear geometry than a C-170. I made new rigger arms. I did not have the factory installation drawings and mine were installed on a Field Approval so my IA made me use the ski appendix in 43-13 for the proper ski up and down positions but I cannot remember what those numbers were.

First I disconnected the top rigger bolt on each ski and I adjusted the riggers for mid-range position, then, I made template plates out of thin sheet stock that were rigidly bolted to the original rigger arms on each ski then placed the skis in the proper position/angle for skis up. By placing a pencil in the upper rigger bolt hole, I traced an arc onto the template. Then the skiis were placed in the proper skis down position/angle and traced another arc on the template. Where those two arcs crossed, I drilled the new top rigger bolt hole. New rigger arms were then made off of the templates. A lot of trouble but it put the skis exactly in the proper positions both up and down.

The plane will be fastest with the skis up. Flying with skis down will slow the plane. If you bolt up what you have and go fly it, I think you will be just fine. The critical ski angle is with skis down. You want it to be correct when the skis are down so it keeps the tips up so you don't dig in the tips when you land (NOT good). I don't think you or the feds will ever notice your skis are -0.3°off. With the skis up, they should be somewhere near level with the ground when sitting on the wheels to give maximun ground clearance. Again, I don't think you will have any trouble with -3° too much angle down but to be sure, hook it all up and lower the tailwheel to the ground and see how the skis look in relation to the ground. If they are within a few degrees of level with the ground, you are good.

But, if you are a perfectionist and want the angles exactly perfect like someone I know did, you'll have to make new rigger arms as described above.

To reitterate a point I made earlier, you don't want any tension on the check cables on the AWB-2500s, they should all hang loose. The positioner positions the skiis when they are up and down and do not need any additional tension on the check cables. The front check cables are only there to keep the skis from rotating down too far and the rear are to keep the skis from rotating too far up.

Also, most people install Teflon bottoms and steel skegs to keep ground contact from eating up the ski bottoms which are hard to repair if worn off.

Good luck!
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
User avatar
mdpesky
Posts: 46
Joined: Wed Mar 15, 2006 7:45 pm

Re: Looking for correct drawings for AWB 2500 Skis

Post by mdpesky »

The other issue that I find confusing is the spring loaded rigger arms don't allow the nose of the ski to go any further up, basically the up position of the ski is locked in the maximum nose up position. At the same time, the internal spring in the rigger arm does allow the ski nose to go down compressing down against this internal rigger arm spring. Problem is, to me it looks like when you taxi up to a snow drift and the nose of the ski has to go up hill, the rigger arms will not allow any stretch and nose up ski? How does that work? I would have thought the rigger arm springs would allow the nose of the ski to go up and down against the spring within the rigger arm not just down(dual actuation not singal)???

In summery, why is the rigger arm only allowing compression of its spring when pushing down on the nose but not when pulling up on the nose of the ski? I would have thought it would have worked both ways(double actuation)?
MDPesky:1954 C-170B/C145/Horton Stol, 1960 C-182C/520ci/Sportsman/Vortex/Wing-X/Alaskan Bush Wheel/Atlee Dodge/Ext-bag/Belly-Pod, 2013 Zenair CH750/912iS, 1999 Europa Tri-Gear/914 Turbo
hilltop170
Posts: 3481
Joined: Sat May 06, 2006 6:05 pm

Re: Looking for correct drawings for AWB 2500 Skis

Post by hilltop170 »

Have you disassembled the rigger and checked to see if it is functioning properly? I don't recall ever trying what you are talking about. I think it will be very apparent whether it is working as-designed when the riggers are taken apart.
Richard Pulley
2014-2016 TIC170A Past President
1951 170A, N1715D, s/n 20158, O-300D
Owned from 1973 to 1984.
Bought again in 2006 after 22 years.
It's not for sale!
User avatar
mdpesky
Posts: 46
Joined: Wed Mar 15, 2006 7:45 pm

Re: Looking for correct drawings for AWB 2500 Skis

Post by mdpesky »

Yes, disassembled, cleaned, re-greased. The shaft only pulls under spring tension in compression it bottoms and doesn't move???

Seems to me the spring action should work both ways?
MDPesky:1954 C-170B/C145/Horton Stol, 1960 C-182C/520ci/Sportsman/Vortex/Wing-X/Alaskan Bush Wheel/Atlee Dodge/Ext-bag/Belly-Pod, 2013 Zenair CH750/912iS, 1999 Europa Tri-Gear/914 Turbo
Post Reply