Bungee Material for Landing Gear and Engine Bay Doors

On Sunday, December 3, 2017 at 2:29:35 PM UTC-6, jfitch wrote:
On Sunday, December 3, 2017 at 5:38:05 AM UTC-8, wrote:
I am looking for a source for bungee material for my landing gear and engine bay doors (ASH-26E). The original (German-sourced?) bungee is about 5 mm diameter and stretches to about twice the rested length. The 3/16 inch USA-sourced material I have been able to find (McMaster-Carr, etc.) doesn't stretch quite as much, about 75% rested length. Since the adjustment on the '26's engine bay doors is quite critical, I really would like to find the original (German-sourced?) bungee material with more stretch. Anyone know where I can get some?

Thanks,
Jim

West Marine.

Yes, all good tips, thanks. I have an email out to Rex and Noelle. I have checked just one local big box outdoor store, and they had some 3/16 inch but the stuff they had again only stretched about 75%. There are others close by, we'll see. I haven't checked West Marine or other marine supply, don't really have one very close to me here in Birmingham, Alabama.

Maybe I'm being picky on looking for 100% stretch, but the '26's engine bay doors are a bit finicky on the adjustment (at least mine are). I'm thinking more stretchiness (more like the original material) would be more forgiving and easier to adjust correctly. And might last longer, too.

Thanks again,
Jim J6

Some notes about bungees...

There's a lot of poor quality bungee, with terrible life and no UV resistance. Junk I bought on the road to secure a loose trailer safety chain disintegrated within weeks. Be careful where you source.

Stretch to 100% will result in reduced life. If possible avoid it (not always possible replacing an existing bungee).

To reduce %stretch its sometimes possible to fit a longer expansion track. I've used poly tubing bent with some heat as a track (bungee runs smoothly inside poly track); tubing bent as necessary to fit inside engine bay and give bungee nice length (with heat, take care to stretch and avoid wrinkling tube). This wasn't a '26 however.

Hope that helps!
Best Regards, Dave

On Sunday, December 3, 2017 at 5:38:05 AM UTC-8, wrote:
I am looking for a source for bungee material for my landing gear and engine bay doors (ASH-26E). The original (German-sourced?) bungee is about 5 mm diameter and stretches to about twice the rested length. The 3/16 inch USA-sourced material I have been able to find (McMaster-Carr, etc.) doesn't stretch quite as much, about 75% rested length. Since the adjustment on the '26's engine bay doors is quite critical, I really would like to find the original (German-sourced?) bungee material with more stretch. Anyone know where I can get some?

Thanks,
Jim

This has been well discussed on the ASH-26E owners list.

I have had no problem using McMaster Carr 3/16 (~5mm) bungee cord on my ASH26E, and I've replaced engine bay door bungees several times. It is not rocket science, but you have to not over tighten the cord.

On Monday, December 4, 2017 at 1:03:26 AM UTC-5, Darryl Ramm wrote:
...I have had no problem using McMaster Carr 3/16 (~5mm) bungee cord on
my ASH26E, and I've replaced engine bay door bungees several times...

Um, if you've had no problem, why do you need to keep replacing bungees???

On Monday, December 4, 2017 at 8:00:06 AM UTC-6, Dave Nadler wrote:
On Monday, December 4, 2017 at 1:03:26 AM UTC-5, Darryl Ramm wrote:
...I have had no problem using McMaster Carr 3/16 (~5mm) bungee cord on
my ASH26E, and I've replaced engine bay door bungees several times...

Um, if you've had no problem, why do you need to keep replacing bungees???

I have replaced the gear door bungees on my gliders every few years, usually once they begin to get sucked open in a slip. I get about three years out of aviation bungees, and got one or two years out of commercial (Chinese) cord.
The seemingly short life I attribute to a very light installation preload, to minimize wear on the door surfaces, and constant stretched pressure. either with the doors closed or open. The correct tension therefore falls into a narrow range, which goes away within a few years.
I found it interesting that the aviation cords have a color code for the date of manufacture braided into the jacket.
cheers,
Scott, SHK & Std Cirrus

On Monday, December 4, 2017 at 6:00:06 AM UTC-8, Dave Nadler wrote:
On Monday, December 4, 2017 at 1:03:26 AM UTC-5, Darryl Ramm wrote:
...I have had no problem using McMaster Carr 3/16 (~5mm) bungee cord on
my ASH26E, and I've replaced engine bay door bungees several times...

Um, if you've had no problem, why do you need to keep replacing bungees???

Jeez, the ever enquiring mind of Dave Nadler :-) The rear bungee may gets cut off when you remove the doors. (or if you have enough pairs of hand/your act together you take both doors off at once. And the front bungee wears out after many years.. You might also replace them to improve the style of fastening clip attached to the front bungees. Are those enough reasons? :-)

A common problem is people over tightening bungees on Schleicher motorgliders. The doors can bang around sometimes in flight with the mast extended, overtightening the bungees to try to stop that is not a solution, besides that a reminder to fly more coordinated.