Replacing undercarriage suspension bands

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JimCrawford
Posts: 63

Replacing undercarriage suspension bands

Postby JimCrawford » Sat Apr 13, 2019 9:37 pm

Once again tapping into the Nipper site knowledge base!

I have the aircraft up on trestles as it makes it more stable for trial fits of the engine as I replace the Peacock style mags with a Leburg electronic set up. Consequently the undercarriage legs are 'dangling' so I shall take the opportunity of easy access to replace the tired suspension bands with a new set.
My question is; are the bands under significant tension with the wheels off the ground or can I remove and replace them by hand without having them fly off when I remove the securing bolts? Forewarned is forearmed!

Regards

Jim

Neil Spooner
Posts: 509
Location: Ardleigh, Colchester, Essex, UK
Contact:

Re: Replacing undercarriage suspension bands

Postby Neil Spooner » Wed Aug 14, 2019 12:45 pm

Hi Jim,
Long time since I visited the site, and not sure why I am not getting notifications of new posts......I will look into it.
I would imagine you have done the bungys now?
Neil
A little help goes a long way.
Nipper G-ONCS and G-BALS
RV4 G-IKON

JimCrawford
Posts: 63

Re: Replacing undercarriage suspension bands

Postby JimCrawford » Wed Aug 14, 2019 8:39 pm

Hi Neil,

No, not yet. The undercarriage structure is demounted to clear up a little surface corrosion and to repaint. Everything has slowed down drastically due to unforeseen domestic commitments. I'm also changing the hubs from the 4.95 x 3 1/2 style to 4.00 x 4 . The quote I got for 'old new stock' 4.95 x 3 1/2 tyres was such that I can replace the whole hubs and tyres aircraft set for less that the cost of one tyre of the old sort. And that's even using Tost tyres!

So I'm plodding on slowly.

Jim

Neil Spooner
Posts: 509
Location: Ardleigh, Colchester, Essex, UK
Contact:

Re: Replacing undercarriage suspension bands

Postby Neil Spooner » Thu Aug 15, 2019 10:25 am

......sad you are not flying it.

Yes, the bungees are under significant tension at rest. I designed a tool to fit the bungees which I can loan you if required. It is my Mk1 tool, still haven't got my Mk2 back from someone!

Best wishes,

Neil
A little help goes a long way.
Nipper G-ONCS and G-BALS
RV4 G-IKON

JimCrawford
Posts: 63

Re: Replacing undercarriage suspension bands

Postby JimCrawford » Thu Aug 15, 2019 11:31 am

Hello Neil,

Yes, I'm sad I'm not flying it but..... force majeure. If you have a tool for fitting the u/c suspension then I would be interested in borrowing it. Are you going to be at the rally? My suspension is the Neumann (sp?) bands not the bungee mod, I was lucky enough to get hold of a set and reckoned that they will last 5 - 10 years so I didn't go for the bungees. Rather hoping to get the aircraft airborne quicker but life happens.

Regards

Jim

Neil Spooner
Posts: 509
Location: Ardleigh, Colchester, Essex, UK
Contact:

Re: Replacing undercarriage suspension bands

Postby Neil Spooner » Fri Aug 16, 2019 11:36 am

I can bring the tool with me for you to borrow, but, the Nieman rings can be fitted without the special tool, not so the bungees (perhaps possible, but bent fingers and scratched paint will ensue).

I hope to be at the Rally, but it is very wx dependent of course, possibly camping one night if its warm......what days will you be there?

Neil
A little help goes a long way.
Nipper G-ONCS and G-BALS
RV4 G-IKON

svenolivier
Posts: 8

Re: Replacing undercarriage suspension bands

Postby svenolivier » Sat Aug 17, 2019 8:51 am

Dear Niel
On my DI this morning some of the suspension bands have perished - could you advise where to get new bands, and more importantly, perhaps post a picture and/or drawing for the tool so that i can have one made up - till replacement i am grounded
Many thanks
Sven

svenolivier
Posts: 8

Re: Replacing undercarriage suspension bands

Postby svenolivier » Sat Aug 17, 2019 9:26 am

Dear Niel
Many thanks for the useful posts and the video - it seems the way forward is with a 1080 shock cord.
regards
Sven

JimCrawford
Posts: 63

Re: Replacing undercarriage suspension bands

Postby JimCrawford » Sat Aug 17, 2019 3:36 pm

Hello Neil,

I hope to be camping at the rally over Saturday night, assuming the beer festival is on again. Possibly Friday night as well. Don't bother with the tool if the bands can be fitted without it. I would have gone for the bungee mod but by good fortune managed to get hold of a ring set. Otherwise the mod would have been inevitable, I'll be installing it next time I need to replace the rings.

Now out to the workshop to make up some wheel hubs on the lathe!

Jim

svenolivier
Posts: 8

Re: Replacing undercarriage suspension bands

Postby svenolivier » Mon Aug 19, 2019 7:49 am

It was a whole day's work but i was able to do a test flight at sunset (with a few rolls and stalls turns thrown in for good measure :)
Attachments
PKEQ2642.JPG
support team to help fit the legs :)
PKEQ2642.JPG (142.36 KiB) Viewed 64 times
IMG_7700.JPG
using the tool :)
IMG_7700.JPG (1.33 MiB) Viewed 64 times
IMG_7694.JPG
the new fitted :)
IMG_7694.JPG (1.3 MiB) Viewed 64 times
IMG_7683.JPG
On the tressle
IMG_7683.JPG (1.75 MiB) Viewed 64 times

svenolivier
Posts: 8

Re: Replacing undercarriage suspension bands

Postby svenolivier » Mon Aug 19, 2019 7:56 am

the start of the problem :(
Attachments
IMG_7673.JPG
the front set all but disintegrated :(
IMG_7673.JPG (1.79 MiB) Viewed 63 times

Neil Spooner
Posts: 509
Location: Ardleigh, Colchester, Essex, UK
Contact:

Re: Replacing undercarriage suspension bands

Postby Neil Spooner » Mon Aug 19, 2019 5:45 pm

Hi Sven,
Very interesting trestle design you have there......worth building into the two Nippers I have when I get around to doing them.
Neil
A little help goes a long way.
Nipper G-ONCS and G-BALS
RV4 G-IKON

svenolivier
Posts: 8

Re: Replacing undercarriage suspension bands

Postby svenolivier » Tue Aug 20, 2019 6:28 pm

Niel

Both the tool and the trestle (and many other handy bits) have all been designed and built by the previous owner, Tom Heaslip, who has many posts on this forum, but who, regretably, never got to fly his Nipper. Without the tool, the extra neiman bands and your video i would have been stuck on the ground for a very long time. The trestle works very well and i only need one extra hand to push down the tail to get it on the trestle (the only refinement may be to fit wheels to it?)
regards
Sven


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