Posted by SteveBeaver on Sunday, April 10, 2011 @ 08:48 PM:
Joe Foley and I are thinking about making up a couple of Webber (Neoprene) landing gear mods. I have the drawings, but does anyone have a picture of the finished product? I thought there was one on the CFI website, but I can' seem to find it now.
Thanks,
Steve
Posted by Collin on Monday, April 11, 2011 @ 00:14 AM:
This is Dann Park's Gear
Posted by jb92563 on Monday, April 11, 2011 @ 12:09 PM:
Is this what you are looking for?
https://docs.google.com/document/d/1rgF3a8l646kqt6u71wcrYUM52VfCTvYB39aVXv9LihY/edit?hl=en#
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Ray
RF4D #4057 N-1771 Rectimo 1400cc
http://picasaweb.google.com/jb92563/FournierRF4D
http://www.touringmotorgliders.org
Posted by Collin on Monday, April 11, 2011 @ 02:18 PM:
Hi Ray,
The gear picture you posted is the from Alfred Scherer.
Steve is asking about Charlie Webber's Gear mod.
Posted by jb92563 on Monday, April 11, 2011 @ 04:51 PM:
Seems like the springs would make for a very bouncy landing as they would simply return the energy of the landing back to the airframe after a slight delay along with the accompanying bounce.
I think the idea of the rubber is that it may dampen the landing and act more like a shock absorber dissipating landing shock more instead
of passing it all back to the airframe in a bounce.
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Ray
RF4D #4057 N-1771 Rectimo 1400cc
http://picasaweb.google.com/jb92563/FournierRF4D
http://www.touringmotorgliders.org
Posted by Bob Grimstead on Monday, April 11, 2011 @ 09:35 PM:
Hi Guys,
Bouncy landing? You could say that of all Cessnas too, since they all use Steve Witman's spring steel gear legs (undamped) -- RVs also, plus a host of other types.
Now think of the standard Fournier landing gear suspension -- simple rubber bungees -- again with no damper.
One of my Fourniers (the blue one) has standard bungees. The red one has the Bauer/Scherer steel springs.
As regards landing touchdown & bounces, they are identical.
There is only one difference, which is that the airplane with the Scherer springs rides a little lower to the ground, so it lands maybe two mph faster.
However, the big advantage to those springs is that , because they hold the landing gear fork in a cmore entral position (rather than at the top of its travel as the bungees do) the main fork hits the other casting far less often. And of course, this point where contact happens has been the place where all those castings have snapped.
So, when I have amassed sufficient Euros I shall be buying a set of those steel springs and replacing the tired old rubber bungees on HDO.
I HATE the idea that the steel springs are significantly heavier than Rene's light and simple bungees, but those rubbers only last maybe five years, they are difficult to obtain, and most importantly, they reduce the likelihood of the irreplacable casting cracking.
But that's just my opinion.
Yours, Bob
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Flying and displaying Fournier RF4Ds VH-HDO and G-AWGN, building replica RF6B G-RFGB and custodian of RF6B prototype F-BPXV
Posted by Collin on Sunday, April 17, 2011 @ 10:26 AM:
Hi,
Another picture of the Webber mod.
Dave Milner's Milan
Posted by dannparks on Saturday, June 25, 2011 @ 04:27 PM:
Does anyone know where to get the rubber bumper donuts used in the Webber mod?
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Dann Parks RF4D #4051 N2188 now flying!
Pictures at: https://picasaweb.google.com/111628310900713778468/RF4D_N2188?noredirect=1
Posted by SteveBeaver on Saturday, June 25, 2011 @ 07:35 PM:
www.mcmaster.com Part number: 8637K16
Enter the part number in the search form.
Steve
Posted by dannparks on Saturday, June 25, 2011 @ 08:46 PM:
Perfect. Thanks. How do you cut it? Band saw? Table saw?
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Dann Parks RF4D #4051 N2188 now flying!
Pictures at: https://picasaweb.google.com/111628310900713778468/RF4D_N2188?noredirect=1
Posted by SteveBeaver on Saturday, June 25, 2011 @ 08:49 PM:
A band saw would work well I think.
Steve
Posted by SteveBeaver on Sunday, June 26, 2011 @ 01:40 PM:
I had to buy a box of 100 1 1/2" washers. If you give me your mailing address, I'll send you some.
Steve
Posted by dannparks on Monday, June 27, 2011 @ 11:00 AM:
Thanks, Steve. I think I'm OK in the washer department. I will have some more "mystery parts" posted soon and appreciate help sorting them out.
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Dann Parks RF4D #4051 N2188 now flying!
Pictures at: https://picasaweb.google.com/111628310900713778468/RF4D_N2188?noredirect=1
Posted by SteveBeaver on Monday, June 27, 2011 @ 11:52 AM:
These are the eight disks required to build the Webber gear mod. They were quite hard to find, but if you have them already, no problem.
Steve
Posted by dannparks on Sunday, July 3, 2011 @ 01:40 AM:
I got the rubber from McMaster and it seems to be good stuff.
I did learn something in the process that might be of interest. When I first rebuilt the gear with the old rubber there was a gap between the casting and the orange rubber tube "bumper". See below.
As I was test-fitting the gear I noticed that the gear cover would not fit over the gear when it was up. It turned out that gap was there because the gear strut was not fully extended when the gear was retracted, and it was causing interference. When I cut the new rubber, I made it longer so the gap was closed and there was some tension holding the gear strut extended (top photo). And now the cover fits.
Maybe this was some peculiarity with my Webber mod, but it might be something to look for if you're having issues.
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Dann Parks RF4D #4051 N2188 now flying!
Pictures at: https://picasaweb.google.com/111628310900713778468/RF4D_N2188?noredirect=1
Posted by eugenio on Monday, July 4, 2011 @ 02:36 PM:
Sometimes it happens also with original bungees when they are blow up. When the bungee is new the fork has a couple of millimeters of free play. You can notice that when you remove the old bungees (they are hard to be removed) but when you put in the new ones they fit without problems. If you take a measure between the old and the new ones you will notice the difference.
Eugenio
Posted by Jorgen on Monday, July 4, 2011 @ 05:25 PM:
The Webber gear mod looks nice, but maybe a tad heavier than the original bungees? Is the Webber-mod less "bouncy"?
I guess the Webber mod otherwise is cheaper and easier to replace.
May the 4's be with you/ J๖rgen
Posted by Bob Brock on Tuesday, July 5, 2011 @ 11:57 AM:
Greetings.. I have the Webber gear mod... and one of the problems that I will solve with modification of the snail is that when retracted to the "up" lock position, the two top bolts press against the snail shell and make locking up a bit difficult. I am modifying my snail to attach like Eugenio figured out (from the inside of the wheel side) with a fiberglass extension. I would not have found the problem except for examination of the snail and rubbed parts which are difficult to see. Hopefully, this will solve the gear up lock problem. I don't know which one is best.. so I will try to improve the one I have. I will take some pictures and post.
Posted by dannparks on Tuesday, July 5, 2011 @ 01:11 PM:
Bob, check that the springs (rubber) are pulling the swing-arm all the way up before retracting. I was having the same contact problem with the large nuts and the snail, and found the problem was the rubber (see above).
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Dann Parks RF4D #4051 N2188 now flying!
Pictures at: https://picasaweb.google.com/111628310900713778468/RF4D_N2188?noredirect=1
Posted by eugenio on Tuesday, July 5, 2011 @ 02:23 PM:
Bob, if you're using my way of fixing the wheel shell, use a drop of loctite on the self tapping screws (or machine screws if you use inserts) otherwise if they get loose you will have problems in retracting and extending the landing gear. I had that problem a couple of times before locking the screws. Since then any more problem.
Eugenio
Posted by jb92563 on Monday, July 25, 2011 @ 04:04 PM:
During the RF4D reassembly I noticed my bungee's are starting to come apart, and now I need to replace them soon as well.
Where can I get those bungee's?
What are my alternatives if I want to get away from the bungees, Webber or Scherer bungee replacement?
Looks like the Webber needs a Welded replacement piece while the Scherer fits on the same hardware?
Are there any advantages/disadvantages to consider with those options?
Cost/longevity comparisons?
[Edit by jb92563 on Monday, July 25, 2011 @ 04:04 PM]
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Ray
RF4D #4057 N-1771 Rectimo 1400cc
http://picasaweb.google.com/jb92563/FournierRF4D
http://www.touringmotorgliders.org
Posted by eugenio on Wednesday, July 27, 2011 @ 03:08 PM:
Bungees are the lightest option, but the more expensive, I sell them for about 200 euro each. I heard about EIS Aircraft who sells them for 90 euros, but is just a rumour. Honestly if you have not concern about weight the other two options are quite cheaper and last more.
The Webber one is the easiest to do, the other one is a little more complicated.
Eugenio
Posted by jb92563 on Monday, August 8, 2011 @ 10:38 AM:
I need to replace my bungies as they are totally shot now, and I'd rather just build the Weber gear so future replacements are easier.
Here are 3 .tif files on the Webber mod. I will be in Lake Elsinore next week.
Maybe we can meet when you are down and you can see the results of my fuselage recover and chit chat a bit.
I have all three versions of landing gear suspensions (Zok, Scherer, Eugenio) Your welcome to try them. Also the 5B is flying again.
