Landing Gear Issues

Ideas and suggestions on OS Aircraft Design optimized for CNC.

Moderator: John Nicol

jim.bo
Posts: 139
Joined: 27 Nov 2011, 15:27

Landing Gear Issues

Postby jim.bo » 18 Feb 2012, 23:32

I wanted to start a separate thread for landing gear related info.

I am thinking to use basically the Zenith type of landing gears, both for the main gear and for the nose gear.

The main gear is would be similar to the Zenith CH 601 XL landing gear shown on the Grove Aircraft side on the bottom: http://www.groveaircraft.com/landing_gear.html#zenair It is about 32lbs with the dimensions shown. (Although I know that steel have much better energy absorption properties, but it is significantly heavier, so I go for light.)

(A 10+ lbs lighter version would be the 2 piece Cessna style landing gear that the Midget Mustang II uses seen here http://www.groveaircraft.com/landing_gear.html#mustang, but unfortunately, I don't know, how it is attached to the Midget Mustang, but supposedly it is an excellent installation.)

For the nose gear, I am thinking again the Zenith type of nose gear partially to avoid oleo struts, partially because it is a proven rugged STOL strength landing gear. It is basically a 2" chrome alloy tube moving up/down in two plastic bearing and dampened with a single 5/8" x 8" bungee cord. It is attached to an angled firewall and designed to be steerable but no front brake. The basic setup is visible on the attachments on pg 21 of the CH 601 xl parts catalog.

On the 8xl-01 attachment, the angle of the firewall can be seen. I don't know if we have or can have angled firewall, but for this gear, it would be desirable.

On the STOL-CH-750-LA-2 attachment, the details of the main gear attachment is seen.

For wheels, I am thinking to use the standard 6.00-6 wheel and brake set on the main wheel (it uses a 6" dia wheel and 17" dia, 6" wide tire), but for the front wheel I am thinking to use a 18 x 4.25-10 inch setup (10" wheel, 18" dia, 4.25" wide tire), mainly to help rolling the wheel even if the tire gets flat on landing. Since front landing gear is always the weaker one, and off airport emergency landing is always a possibility, I would like to maximize the chance of surviving it without front landing gear damage (and related prop and engine damage.)

to be cont'd...
Attachments
STOL CH 750-75-LA-2.pdf
(131.22 KiB) Downloaded 172 times
8xl-01.pdf
(118.89 KiB) Downloaded 148 times
xl-parts-cat1.pdf
(3.06 MiB) Downloaded 152 times
Last edited by jim.bo on 19 Feb 2012, 11:25, edited 2 times in total.

WoodenWings
Posts: 77
Joined: 12 Dec 2011, 20:04

Re: Landing gear

Postby WoodenWings » 19 Feb 2012, 00:30

See the landing gear link on the new page i made.
Also - i believe the zenith nose gear is patented.
good pdfs.

Shane

jim.bo
Posts: 139
Joined: 27 Nov 2011, 15:27

Re: Landing gear

Postby jim.bo » 19 Feb 2012, 00:34

The steering is visible here...see steeringrods attachment....to the same two pedals, the hydralic brake cylinders are also attached, but they are not visible on this particular picture.

As far as design details, I have acquired the Pazmany books, but they are a difficult read. The main landing gear calculation is 25 pages of solid formulas. (Of course Grove will be happy to design it for free, as long as they get some business out of it.) But I found some easier to use design info in the September 2004 EAA Sport Aviation magazine from the Neil Willford. It is usable for both flat (like the Grove main gears) and rod type of landing gears. See main landing gear design spreadsheet attachment. Unfortunately there are basic dimensions needed for the spreadsheet that I don't have, including the width of fuselage, the prop clearance with the current landing gear, etc. But once they are known, the spread sheet works well.

Also here is some fairing idea for the nose gear http://www.utdallas.edu/~klaus/Airplane/nose_gear_fairing.html.
Attachments
LandingGearDesign.xls
(187.5 KiB) Downloaded 116 times
steeringrods.gif
Last edited by jim.bo on 19 Feb 2012, 02:11, edited 4 times in total.

jim.bo
Posts: 139
Joined: 27 Nov 2011, 15:27

Re: Landing gear

Postby jim.bo » 19 Feb 2012, 00:37

WoodenWings wrote:See the landing gear link on the new page i made.
Also - i believe the zenith nose gear is patented.
good pdfs.

Shane


What is the patent number? What aspect is patented? And is it still valid, because he designed his gears long long time ago? (I did a quick search, but could not find patent on it)

...and what landing gear page do you refer to...can't find it....

jim.bo

User avatar
John Nicol
Posts: 389
Joined: 23 Nov 2011, 12:17

Re: Landing gear issues

Postby John Nicol » 20 Feb 2012, 11:04

I went to the Onex webinar hosted by EAA and they had some images and discussion of the steerable nose wheel (and tail wheel) configuration they use on that aircraft. It was very informative. I think that there were some interesting ideas in that presentation that could be applied to MakerPlane.

http://www.eaavideo.org/channel.aspx?ch=ch_webinars

WoodenWings
Posts: 77
Joined: 12 Dec 2011, 20:04

Re: Landing gear issues

Postby WoodenWings » 21 Feb 2012, 01:07

Chris Hientz -
http://zenithair.com/kit-data/ht.html

Humm i can't find it either - i swear i read it regarding the newly refreshed Zenith?
It had to do with the bungee system. Must have been a load of guff!

Shane

braywood
Posts: 5
Joined: 10 Aug 2012, 07:49

Re: Landing Gear Issues - Carbon Fibre

Postby braywood » 25 Aug 2012, 04:33

Anyone with experience designing carbon fibre main landing gear? I am thinking a wood laminate shaped core, with carbon fibre shell; could it be strong enough for a 1200 lb aircraft?? It would simplify the build for many by avoiding the metalwork. Mark

hedley
Posts: 3
Joined: 31 Aug 2012, 08:09

Re: Landing Gear Issues

Postby hedley » 31 Aug 2012, 12:49

Check out Chris Heintz book Flying on your own wings - takes detailed and slow reading but great resource . If retracts used I wold recommend getting festo fluidsim software to check out all hydraulics with great simulation . Also Dan raymer books good guidelines .


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