FNG Newbie Alert! New LE Rebuilder

[Victor Bravo]

I found an online build log for Chris's Legal Eagle XL named Bulldog. It clearly showed the control stick ass'y.

My proposed assembly is a lot more akin to well-established homebuilt designs using push-pull tubes instead of cables:

[IflyHG]

Regarding the Tuffy plastic bike wheels.  I have no first hand experience but others have shared your concern and it is also my understanding that either they are no longer available or are hard to get.  An alternative that many have used is heavy duty BMX wheels in the same size.  Many BMX riders are full sized adults and they put all kinds of unique loads on wheels so there has been some development in the industry.  The approach is to use a double wall aluminum rim, heavy duty spokes, and a hub that accepts the largest diameter bearings they can find, usually 15mm inside dia.  The larger bearings enable a larger diameter axel.  The typical number of spokes is 36 for a standard wheel, but 40, 44, or 48 spoke rims may be available and stronger.  Also, the more times the spokes cross each other (2x, 3x, 4x) the stronger the wheel.  The rims and hubs need to match of course.  If you want brakes too then you will need a hub that supports disk brakes.  The bolt circle for disk brakes is standard, 160mm disks are the most common and have been reported as more than adequate for a LE.  Talk to your local bike shop about what you are doing and what you want.  You don't want a wheel set, you want 2 fronts.  They won't be cheap.

[Brock]

I've always wondered about those bike wheels on an aircraft.  Bike wheels are not made for much side load while it's not unusual for an aircraft to not be completely straight upon landing (depending on technique).  For this reason I'm favoring the Black-Max wheels for my build.  On the other hand the bike wheels give more prop clearance.  I suspect a 67" prop on a Verner would make this into a big deal but with a  1/2 VW not so much.  Alternative would be longer gear legs.

[IflyHG]

The design of the gear legs should be based on the intended wheels to be used, so if you are building an LEXL and you want large diameter wheels the gear legs need to be adjusted accordingly.  In addition to prop clearance the angle of attack of the wing when on the gear should be a consideration.

WWI vintage airplanes basically used bicycle/motorcycle style spoked wheels.  To address side loads the hubs were 2X-3X wider so the spokes formed a wider triangle.  If you are willing to design & machine your own hubs you could do the same, I've seen pictures of this in recently built ultralights.

The limiting factor is tire traction on the surface.  Landing on grass or dirt the tires can't generate enough grip to overload the rims.  Landing on pavement and using light duty rims there have been wheels that have bent.  Heavy duty double wall rims, with heavy duty spokes have proven more durable.  Bicycles have a standard fork width which limits how wide the hub can be for bicycle applications.  If you want to use off the shelf parts the heavy duty parts are the way to go.

Large diameter narrow wheels have several benefits.  They have lower rolling resistance, especially in taller grass, so takeoff runs are shorter, the larger diameter is smoother over bumps and irregularities, and of course more clearance for the gear.

[Dan_]

Side load is a peav of mine.  There is a youtube video of a LE that experienced probable carb ice from an extended reduced power final approach and a low throttle ride down the runway.  At the far end he decided to go around and had to land.  The swerve to avoid the fence warped up the Tuff Wheels but the tire stayed on and the wheels were fine.  The landing gear had to be rebuilt.  Point being the GD plane is supposed to be landed straight and in the first 3rd of the runway.  Where are the side loads going to be coming from to bend the rim and peel the tires off?  The gear is going to fail first...

https://youtu.be/VIIRW8u8nB8?list=UUopLDNHH_5BR8eBpJgrJfAA&t=30

https://www.eaglersnest.com/forum/index.php?topic=1823.msg10351#msg10351

Search button is your friend...

[Brock]

Thanks IflyHG & Dan for the responses.
Lots to learn from that video.  I'm just a "plans-owner" at this point and yes the Search-box/button has been my friend.  There is a lot of meat to find as a newcomer to an active forum.  Takes time to sort it all out.  Plz be patient.

[Dan_]

It's all good! Dint mean to give a bad/wrong impression.  It's that topic in general.  There has never been an issue with wheels strong enough to hold up the plane.  The Tuffies are still flying today, and bicycles and airplanes were intertwined from the start of aviation...  If a plastic wheel is stronger than the landing gear I'm betting just about any adult bicycle spoked wheel is never going to be as issue.  There are some cross zero spoked "chopper" bike wheels that may not be suitable however.  This is twice for me today I have been on a tear.  Think I'll take a nap...

[Chuck in Indiana]

Bullet's double wall BMX wheels have proven to be fine. (so far)  Many xwind landings, a couple of landing gear tests  etc. The very light brakes will hold at a full power runup, believe it or not.
*I don't remember* if I had to turn the axles to fit. Sue me, I'm old..

[Brock]

Thanks Chuck,

I did a search on "Bullet's double wall BMX wheels" but there were too many results to be useful.  Lots & lots of BMX wheels out there.  I'm curious about the axle.  Do your wheels have sealed bearings and you just used an appropriate sized bolt/stud.  Never been a BMX biker so I don't know the tech.

[IflyHG]

Check out this link (if it works) https://www.eaglersnest.com/forum/index.php?topic=2197.msg13624#msg13624.  It shows Chuck making axels to fit the bearings in the hubs.

[Brock]

Perfect!

[Victor Bravo]

Well.... I was looking at the inside of the wing on my new-to-me LEUL, and I saw something I want to ask the forum brain trust about. I remember reading something on this forum about making sure you do not touch or notch the main spar caps when you're drilling the holes for the aluminum spar root fittings.  On at least one of my wings, it appears that the bolt is "perilously close" to the spar, as had been mentioned on another build thread.

Can someone verify whether the bolt location in these photos is or is not in a safe location? I cannot imagine that the hole for this bolt does not "notch" or weaken the upper spar cap underneath the plywood plate.

[Dan_]

Check out this link (if it works) https://www.eaglersnest.com/forum/index.php?topic=2197.msg13624#msg13624.  It shows Chuck making axels to fit the bearings in the hubs.

The link doesn't work for me...  Did you do it like in the "how to post" video?

[IflyHG]

I didn't watch the video so probably not.  I used the "insert a link" button on the tool bar and then populated the URL and display fields.  I had tested the link by copy/pasting it into a new tab to verify it went to the right post.  I just tried it from your reply and of course it didn't work for me either. 

[Chuck in Indiana]

Testing.. page 20
https://www.eaglersnest.com/forum/index.php?topic=2197.285
it went right to page 20