Turbulent landing gear

[abgd]

Does anybody know the toe-in or toe-out settings for a Druine Turbulent, empty?

I gather the Rollason Condor (a related design with a very different undercarriage) is meant to be set somewhat toe-in.

[OpenCirrus619]

Give the Tiger Club a call - they have a number of them.
The Tiger Club, Sport Aviation, Aerobatics, formation flying. air racing, air races. display flying (http://www.tigerclub.co.uk/)

OC619

[Tony Mabelis]

I'm not sure of the exact settings in degrees, but it is definitely "Toe in" that is required if you dont wish to emulate a Kangaroo on take off and landing!!
Tony

[La4a]

Turbulent D31a drawings show toe-in as 0" to 1/8"

[abgd]

Thanks, much appreciated.

[abgd]

Drat... Bigger problems than I expected. The axle is completely shot and the gear needs a fair bit of work on it.

I gather it's fixable but is a big job requiring some new parts to be made.

If anybody knows of any landing gear for a D31A that is looking for a home - perhaps from an abandoned aircraft or unfinished project - please PM me.

I've also seen pictures of Turbulents with sprung landing gear. If anybody knows anything about tried and tested mods - in the UK or abroad - I'd be interested to hear.

[abgd]

I don’t like to think too much about how the axles became so warped. Two thoughts are that they may have been ‘rescue’ undercarriage from another plane that was written off. Another is that they have had the screw at the end brazed into position, possibly destroying the temper of the axle. Either way, the relatively spindly mounts on the spar seem in good condition and my inspector is happy with the condition of the spar.

So, clearly the axles need fixing and one of the brake backing plates needs replacement too – which is within my ability but I suspect it would be easier simply to replace them. They’re operated by bicycle cables and I’d prefer not to change that aspect of the system.

The wheels are 5"; the axle is 1" and the brake hole spacing is 3.75" diameter. The current brake drum is 4" internal diameter.

Does anybody have any suggestions as to what they would replace the brakes with? Cost is a consideration. It’s been put to me that I should opt for disc brakes. The only drum brakes I've found so far that might work are from avusa and seem to have a mixed reputation.



https://farm8.staticflickr.com/7550/15127702554_9b974d6ec7_s.jpg


https://farm4.staticflickr.com/3949/15747663935_8d917a326a_s.jpg


https://farm8.staticflickr.com/7551/15562503407_4ff6df399e_s.jpg

[cockney steve]

With such a small, light airframe,have you considered bicycle brakes?
Both disc and drum are used and operation is cable, (as you already have) hydraulic or rod.
Inch bar seems quite small for a cantilever axle Maybe it's just had a heavy landing or two,maybe with wrong tyre pressures. I think it unlikely the axle would be welded to the gear-leg and then the whole shebang hardened and tempered....more probably it's just a lump of bar of the correct grade, turned as needed and welded-on.
You seem to be at the bottom of a steep learning-curve here.AIUI, you are expected to come up with the ideas for a fix or mod and then submit it to LAA engineering for approval. that is, they don't do the ground-workfor you......so,that leaves owner's associations, other Permit flyers , friendly engineers/mechanics or paid engineers.
You could sit downwitha load of textbooksand a calculator and workout what spec.of material is needed etc......but my gut feeling is that , from what is already there, you should get a good idea of what would be suitable.
You may also find the importers of small "quadbikes" and mini-motorcycles may well list drums/backplates/shoes etc. which can be modified.

There are plenty of firms who will reline bonded brake-shoes or supply lining-material/rivets todoyour own. Have you looked at the possibility of straightening the axle(s) ? Cracking is not likely to be an issue, many firms specialise in straightening motorcycle forks and frames.
Unfortunately your pix are too small to see a great deal.

HTH.

[gasax]

You will find far fewer challenges in repairing items rather than replacing. If you replace you will have to get the changes 'engineered' to get through LAA engineering.

If you repair then that process is much simpler. I had a 601 with the azusa cable brakes - they were ok. much better than those on an Auster (although that is not saying much). With a Turbulent's lack of mass really effective brakes are more likely to put it on its nose.

I seem to recall reading years ago, that there is a limited movement in the undercarriage and this was being blames for spar damage on I think Turbulents. Certainly I have seen similar distortion on at least one microlight and they have significantly stronger undercarriages than these older very light aircraft courtesy of Section S.

The most straight forward option is to simply replace the axles and repair the brakes anything more has the potential of opening out into a project and significant downtime.

[Mechta]

The picture is too small to see the exact configuration of the axles, but would it be possible to swap them left for right and vice versa, so the toe out becomes toe in?

Glider wheels would be about the right size if you were considering changing to something newer. Tost are the main supplier. Sit down before reading the prices. Skycraft do used ones, even theirs are pretty eyewatering:

Used Glider Wheels at Skycraft (http://www.sky-craft.co.uk/acatalog/Skycraft_Used_Glider_Wheels.html)

[blue up]

http://i82.photobucket.com/albums/j279/foggythomas/DSC03225.jpg

Similar to these? Leftovers from my Clutton FRED. Might be the wrong size for a Turb, though.

Toe-in on the FRED leads to toe-out when towing it home from the airfield. Quite handy (except mine were also bent!)

[abgd]

Thanks for the suggestions.

Original pictures are on www.flickr.com/photos/flowtik (http://www.flickr.com/photos/flowtik) but for some reason they've ended up miniaturised here.

Rebuilding the brakes would involve fabricating at least one new backing plate from scratch, so if it were simple to buy something similar and weld it into place that would be easier. Given that I need new shoes or resurfaced shoes, the AZUSA option wouldn't be that much more expensive either.

I don't think that straightening the axles is likely to work. We did consider it, but they're straightened, squished, slightly angle-grinded in order to get the wheel off and somehow or another they've already failed so my feeling is that replacement is likely to be better. I could probably fit a larger diameter axle in the wheel using different bearings - which also need replacing.

Thanks for the picture of the FRED wheels - they are the same.

[Sir Niall Dementia]

Slightly off-topic. There was an article in the PFA mag years ago about someone restoring a Turb. He found that the Undercarriage springs weren't strong enough to stop bottoming out in quite a "gentle hard landing." and that as a result a previous pilot had knackered the spar without realising it.


He did a lot of maths which went way past me, the bottom line being he fitted stronger springs with PFA approval to avoid further spar damage.


SND

[cockney steve]

It's a home-build aircraft...the plans will probably specify the grade of steel bar you need , it's probably a common broght cold-rolled steel but there are many different grades depending on application......if there is ant turning, therading to be done, the right selection will be more easily machined. likewise if it doed need heat-treatment.....It isn't going to be terribly high-level metallurgy, given the age of the design and the far superior material available today. If you look round, there are plenty of small engineering shops /fabricators or model engineers who have the equipment and knowledge to make and fit replacements as needed.....I'm sure the LAA can help, but fromwhat i've heard, they don't expect to spoon-feed you.....they may well know someone in your area, maybe even a local "strut" member has the time/facilities/ inclination to help you.

S N D raises a very important tip. That looks like a total no-brainer! If I owned a Turb. I'd put the spring-mod at the top of my list and given your axles are bent, I'd check the spar very carefully indeed.

Oh, and there are many spring-makers who can make to pattern or spec. anything including vehicle suspension springs,down to a tiny spring in a bracelet-catch. You may need a business directory from the local library,considering how dire "yellow Pages" are nowadays.