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View Full Version : Bigger bungies??



Wayne Jacobson
12-11-2007, 03:02 PM
Has anyone used 1380's for their bungies? The plans for the V6 STOL from Dave Blanton call for two 1380s on each bungie. The ear on the hydrosorb must be ground off to make room for the two bigger bungies. His logic is that the plane has a gross weight of 2200# and the bungies will expand at 1.2 Gs. Any comments?

Super Pacer
12-30-2007, 11:23 PM
Hi Wayne,

The larger bungies are really dificult to fit to the stock Pacer / Tri-Pacer hydrosorb fittings. A pilot here on the field just build a extended fuselage / Super Cub wings & O-540 Lyc "Monster Pacer" and he had to use PA 25-150 (Pawnee) Hydrosorbs, as his empty weight was about 1600 lbs!! They fit well, with the only "mod" necessary was the AN-6 bolts instead of AN-5.

As for the stock Hydrosorbs, I plan to modify my pacer units to accept two 1280HDs by welding slightly longer mount tubes to each end. This is what the Pawnee mounts look like, only they are large enough to take three bungees each.

Enjoy the day,

John
SWPC Utah

n8714d
12-31-2007, 02:09 PM
Hi Wayne,

The larger bungies are really dificult to fit to the stock Pacer / Tri-Pacer hydrosorb fittings. A pilot here on the field just build a extended fuselage / Super Cub wings & O-540 Lyc "Monster Pacer" and he had to use PA 25-150 (Pawnee) Hydrosorbs, as his empty weight was about 1600 lbs!! They fit well, with the only "mod" necessary was the AN-6 bolts instead of AN-5.

As for the stock Hydrosorbs, I plan to modify my pacer units to accept two 1280HDs by welding slightly longer mount tubes to each end. This is what the Pawnee mounts look like, only they are large enough to take three bungees each.

Enjoy the day,

John
SWPC Utah
Guys,
It is about time to change bungees in my PA22/20.
A friend suggested the use of 1280HD, but now I read about the need to change the hydrasorb unit mounts?
Thanks,
Miguel
N8714D
PA22/20-150

Wayne Jacobson
12-31-2007, 02:17 PM
Miguel, a lot of folks use one 1080 and one 1280 on each hydrosorb. This should not require any change to the hydrosorb unit. I have not tried to install my two 1380s yet so I might be in for a surprise.

Wayne Jacobson
12-31-2007, 02:19 PM
I would be interested in a picture of the modification when you do it. I have not tried to install the two 1380s yet but by grinding off the separating ear on the one end of the hydrosorb, it is supposed to fit. But since I have not done it yet I remain hopeful but flexible.

portouwl
01-01-2008, 11:50 AM
Miguel, a lot of folks use one 1080 and one 1280 on each hydrosorb. This should not require any change to the hydrosorb unit. I have not tried to install my two 1380s yet so I might be in for a surprise.

When you use a 1080 and a 1280 on the stock hydrosob, put the smaller one on first. Doing this preserves a little bit of ear to hold the larger one in place on top of it. I found that doing it the other way, it was difficult to keep the small (second) bungee on. It had a tendency to slip off. My '22 squatted a bit with the standard 1080s on it. One of each has it sitting up like it should and helps takeoff control by reducing the angle of attack on the ground. I didn't get much of a vote on when it was going to fly with two 1080s on it.<o></o>

SandyM
01-01-2008, 02:46 PM
I can't say what effect the different bungees has on the handling of the airplane as I've not flown mine yet. However, we did just replace the bungees with the 1080HD's and 1280HD's just a week or so ago. Unfortunately, FAA registration paperwork is keeping us on the ground.

However, as far as physically replacing the bungees, I agree with portouwl's comment in that you should put on the 1080HD first and then the 1280HD. We also tried the 1280 first and it didn't leave any lip on the hydrosorb to hold the 1080 on. I've heard people say to do the opposite but I really don't know how they could make it fit. We also worked to roll the second bungee onto the hydrosorb so it ended up resting against the body instead of the lip.

The second issue we found is that once the hydrosorb was loaded with the 1080HD/1280HD combo the head of the mounting bolts rubbed against the top bungee. I'm guessing that once it takes a few landings the bungees will pull down a little and this won't be a major issue. However, since I guess a 1380 has a larger diameter, I don't know if you could still mount the hydrosorb into the plane.

Besides, the additional strength of the HD over the std. bungee coupled with the mixing of a 1280 and a 1080 seems like a pretty major upgrade from stock and don't you want some give in your bungees? However, I will admit I don't know anything as I've still not flown my PA-22/20.

WHile you are doing the bungees has you checked to see if your gear has the added gussett Univair has a service buletin for. After seeing how weak the gear looked like without it, I'm really glad we did that at the same time.

Wayne Jacobson
01-03-2008, 03:53 PM
I will actually be making my gear myself so the Univair gusset is not an issue (although I will make sure it is adequately reinforced) I will also be using Eddie Trimmer's reinforcement of the streamline tubing. For $50 Eddie will send you the drawings and copies of 337's that worked in Alaska, of course I will not have to worry about 337s being experimental. I am really getting courious as to how the 1380s are going to fit.

SandyM
01-03-2008, 04:47 PM
I know the 1080's are 5/8" diameter and the 1280's are 3/4" diameter and these barely fit. Do you know the diameter of the 1380's?

Geoff Newcombe
01-03-2008, 05:36 PM
http://www.aircraftspruce.com/catalog/lgpages/shock_rings.php
1380's are 13/16's