NOSE GEAR SPRING QUESTION???

[EDMO 1078]

I plan to have a spring-loaded pivot shaft on my nose gear.

Question:   Estimating a nose gear weight of approx. 120 lbs, would I want the spring to be about 60 lbs compressed, 120 lbs compressed, or something more than static nose gear weight?

None of my books cover this - most nose gears have a hydraulic or air shock mount, but I don't have room for that.   Any thoughts appreciated.

Thanks,

EDMO

[ChrisBolkan 130]

Can you post a sketch? I do not understand what you are describing.

I am expecting around 100Lb on the nose of my Flat Avid with 912. Maybe a bit more. I don't know. I have to chose a spring for mine too. I expect the spring not to compress at all when installed and only compress when the wheel rolls over bumps. I suspect the loads will be sudden and fairly forceful but brief. Since I have a fairly large tire up there and plan to run low pressure I am really not counting on the spring doing much. I will chose the spring by feel and may end up trying a few different rates before I come to what seems right. I am guessing somewhere between 200 and 500 LB to compress the spring will be about right, but that is a guess.

[EDMO 1078]

Chris,

     I was hoping you would read this.  I might - that's a big "might" - be able to draw something if I have to -

Just imagine your fork welded to a 1 1/8 x .188 wall tube and putting a spring over that tube between the fork and the nose mount that the tube slides thru. 

     The book I have says you should have between 10% and 15% of total weight on the nosewheel - but 12% to 15% is better.

I just want the spring to cushion some of the impact.   My 6.00 x6 nosewheel and the fork of a Tripacer or 206 should handle more weight than I will put on it.

EdMO

I think I will look for some motorcycle or ATV springs and see what I can come up with. 

Right now, I just have a 60 lb/inch spring and possibly a 720 lb/inch spring to try.  I think the 720 is too strong.

 

P.S.  I was thinking more about higher pressure in the nose tire than the mains - to make steering easier???

Edited 16 May 2014 by Ed In Missouri

[Luked 71]

Hi Ed,

 

I needed a coil spring for a special project a while back, and I found several websites that sell custom and a wide variety of stock coil springs. I think the one I ended up using was this one:

 

http://www.centuryspring.com/

 

You can search through their selection on this page:

 

http://www.centuryspring.com/Store/search_compression.php?reset=1

 

The advantage is that you can see the exact specs for the spring before you buy it. In your case, You might start with the inside diameter as your first search criteria (to fit your fork tube). Then maybe suggested max load, or spring rate if you have calculated that. Most of them don't seem too expensive, so you can afford to buy more than one option and experiment. That's what I did.

 

Luke D.

[wypaul 448]

Ed are you talking about a trailing link nose gear? There is a video on YouTube under "Avid trailing link nose gear" that will allow others to see what it is.

I tried to post a link but this site doesn't like IE and I don' t know how to do it from my IPad either.

 

Keep forgetting about Chrome.

 

Edited 17 May 2014 by Paul S

[EDMO 1078]

Paul,

     I think that video is somewhere on here - Snowpaw or someone sent it to me a long time ago.  I have one of those nosegears,   They sold for $1000 each!

ChrisB used to have one too.  His plane photo is on the video or ad for it - Unfortunately, it is no longer made or sold.

Mine is a trailing gear by about 26 to 30 degrees trail from a -5 degree vertical pivot post - the spring I am thinking about just goes on the swivel post to let it go up with weight or act as a buffer.   Hope this is somewhat clearer than I can understand it?

Luke,

     Thanks for the site.  I will check it out if I cant get what I need - Then I have to figure out WHAT I need, and that may take a little while.

Thanks both,

EDMO

Edited 17 May 2014 by Ed In Missouri

[EDMO 1078]

Paul,

      That is a different video than the one I saw with the gear on a Challenger running over a 2x4 and rocks, and ChrisB's Avid with the Kayak under it.

Looks like same gear tho.

EdMO

I may have found some minibike springs for a start.

Edited 17 May 2014 by Ed In Missouri

[wypaul 448]

Rans gear has a spring that also disengages the steering while in the air so that it doesn't act like a nose rudder.

[wypaul 448]

Here is another spring company.

 

http://www.springsfast.com/

[EDMO 1078]

Paul,

     I have studied the RANS nosegear - good design.

Mine is not steerable - yet - never have flown a castoring nosegear = may change my mind once I try it.

EDMO

[wypaul 448]

The are plenty of planes using the castoring nose gear so I bet it will be well suited for you.  RV and TriQ to name just a couple.

[EDMO 1078]

Kitfox is castoring too.   I flew several planes with the disconnect on the nose wheel, but without a disconnect, and slipping to a landing with cross controls, the nose wheel is following the rudder, and can make for some very interesting swerves when you hit the ground.  The Ercoupe was a terror in that respect, but it always landed better than the pilot thought it would.

They say that castoring and steering with the brakes until you can steer with rudder is fairly easy once you get used to it - guess most things are that way - just another learning curve.  I like to get the nosewheel off of the ground ASAP.

Guess everyone but me knows what kind of tailwheel that is???

EdMO

Edited 17 May 2014 by Ed In Missouri