Eagler's Nest
General Category => Builders logs => Brock's bits - LEXLV3 => Topic started by: Brock on January 04, 2025, 04:44:26 PM
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Yesterday I got a call from "NW Ambush Extreme Sports" that my wheels were built and ready to pick up. The shop owner said her tech was really impressed and liking this build. He thought they would be extremely strong. I've no plans for destructive testing to find their limits.
Here is a parts list, mostly for my records but someone here might find it all interesting.
Rims - Box One 406mm x 22mm Rims.
Tires - ETB00419600 Maxxis E-Cargo E50 Tires
Hubs - Origin-8 MT-3300 MTB
Spokes - Wheel Master #56201 Size 7.4-188 14G Stainless
Weight w/o brakes is just under 4 lbs.
Takes a big 20mm axle (just over 3/4"). Haven't decided if I'll go with 3/4" and a sleeve or turn down something from 7/8" or find a 20mm tube.
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Yep, those are sturdy, all right. :) Mine are considerably daintier (is that a word?) :) but I've had to true/tighten the spokes once in 50 hours.
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Just a rough guess here but spokes are prolly 50 times stronger than mags... (ask any BMXer or MTBer) So wheels laced with cross 4 spoked rims --especially modern ones have to be about a hunnert times stronger than plastic mags.
:emoji_u1f62f:
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You ain't nothin' but a hound dog
Cryin' all the time... Elvis
Leonard would smile saying "you a good scrounge dog" looking on Clist/FBook marketplace for old BMX bike with 20" wheels
"Scrounge" is a verb that means to look for or get something, especially when you ask for it instead of buying or working for it. For example, you might scrounge for money, food, or tools.
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OK, I admit the pictures below don't look very much like 'wheels or landing gear' but hold on a minute.
I got distracted from making the seat when I realized having a seat is not very practical without something to hold the plane onto the ground. A crash from two saw horses in an airframe with out wings would be embarassing to explain. So I decided I'd have to bite the bullet (sorry Bullet no pun intended) and get to work on the gear. But I soon came to an obsicle of where to put the gear. It's hard to reference the leading edge of the wing if there is no wing. Thus the mockup picture below, my Landing Gear Reference Tool. After all that really is the first use of a wing right?
So for those of you in the know. Does the positioning of the wing look about right? (except for being a bit high) I really want to get the airframe mostly done before starting the wing.
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Close enough.
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The square tube will probably be directly over to uprights... you'll have the 'plate' that will come up the aft side of the uprights & halfway up the aft side of the square tube, if that makes sense... But back to your original question, with the fuse level, drop a plumb bob from the cluster and you'll want the 'centerline' of the axles to be 6 inches forward from there... Hope that helps...
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The square tube will probably be directly over to uprights... you'll have the 'plate' that will come up the aft side of the uprights & halfway up the aft side of the square tube, if that makes sense... But back to your original question, with the fuse level, drop a plumb bob from the cluster and you'll want the 'centerline' of the axles to be 6 inches forward from there... Hope that helps...
That helps. Always wondered about the 6" reference. Read a few comments on it but never had it clearly spelled out as to where the 6" started.
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Finally some progress on the landing gear. As others have found out, the angles and locations are not all that clear. I settled upon fixing the axle under the wing leading edge. The axle 'line' and plumb bob can be seen in the first pic. However that gave me a whopping 19 degrees (measured at the pivot bolt). Clearly, when I look at the profile (pic below) it looks a bit extreme. Since I'm so far down this path I'll continue and reevalute as the craft takes final form. The little rear pivot stub that connects to the 5/8"x.035 "drag-tube" (for lack of a better name) is made from .049" (might be thicker). Since this item is mostly side loaded I wanted it rather stout.
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That looks pretty similar to what I have, and it will be fine.
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Feels good to finish a stage or goal. Felt good to get these two landing gear both welded up. I'm thinking the suspension/cabine should go quickly. Then, then I'll get to see it with wheels on. Ok, enough celebration.
The gear, as some have said is a lot of welding and figuring. Two things learned. One, I tend to not use enough amperage when I weld (afraid of burning through) which in the end caused me to heat the overall part more than should be. Still don't know how to get over this learning hurdle but occationally I get it right and am rewarded with a beatiful weld. Like the other day when a friend wheeled his champ restoration to get tabs welded. We were both impressed with the first weld which turned out to be luck. Ha.
The second lesson, can I call it that since I still don't know the fix, is that sometimes welding bends things. Like the this picture with the straight edge. Seems after welding that last little brace my main gear bent a degree or two. I imeadatly know something was off on that first gear leg when it didn't swing as nice before after welding. Deciding I had gotten it too hot (see lesson one) the second gear leg I carefully welded in short stiches and let the tube cool then came back and welded some more. Still this second leg came out the same as the first one. Oh good, I thought, now the camber is welded in. Live & Learn.
Happy Resurection Day! (Easter) to you all.
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Like many things when building an airplane, by the time you are done you are much better at various tasks than when you started. :grin: The FAA lets us do this for "Education and Recreation." It's an education all right.
Although I'm a fairly decent gas welder, I made myself *learn* the TIG that I have owned for years but really didn't know how to use it when building Bullet. Oh, I could do heavy around the farm welding, but .035 tubing and aluminum completely baffled me. Hours and hours of watching videos, and 2 tanks of Argon later I was ready to start tacking. Some of the first welds were..uh.. ok, but by the time I finished I was beginning to get the hang of it and welded the aluminum oil tank without issue. I could do a better job on the next one, and so could you. ;)
Yes, you are afraid of burning through and not using enough pedal to start. Heat build up is caused by *time* on the weld.
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Finally standing on it's own two....wheels.
The cabine was easy to make and more fun, for sure, than the gear legs. One lesson I learned which I wish I had thought of earlier. Clamp the cabine plates in place but don't weld until the shock-struts are cut and in place. This way the angle of the plates can be tweaked before welding. As it turned out, one shock-strut lined up nicely with the axle but the other one was a bit forward. A little heating and bending put it in place but if you know where to look you'll always see that little imperfect tube. I'll aways see it.
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Trust me. you'll forget all about it by the time you are flying. Oh, and you'll probably need something stronger than blue tape for the engine mount. :))
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Just when I had finished the engine mount I breathed a sigh of relief thinking the airframe part was all down hill from now on. Ahhh but then came the brakes! In the end they came out ok. without any consideration I worked on the right brake caliper mount first. Turns out it was the toughy and if I had done it second it might have turned out better. What makes the calipers difficult is that bike brakes are all one sided, no right & left to keep things semetrical. So 'semetrical' gets tossed with the short welding rod nibs.
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One more bite off the elephant.
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Seems like I spent hours in the hangar today and accomplished nothing. Ah! but I did figure out something I've been noodling for a very long time. So that was something, and if it works, something big.
Here is my idea for the Toe Brakes. The handles are some sort of plastic, hydrolic setup. You've seen the calipers. Pic is a short video (Double click it use space bar to play). I can't see any reason this wouldn't work with cable brakes as well.
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I was going to just mount them horizontally on the floor, (al la Cub heel brakes), and save the weight and complexity. I like the way you think though!
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Yesterday I managed to trim the tubing and bleed the brakes. They pumped up nice and firm. I think these toe brakes are going to work out well.
Today I finished the basics of the tailwheel. There still is a lot of weight to shave off the tailwheel but I have the basics installed. I decided to go with the plans spring steel setup as I'm thinking I will need the weight back there. And there is no lighter way to add ballast then in the tail wheel. The horizontal is not currently mounted but I notice that it takes a bit of weight to keep the tailwheel on the ground. Have others noticed if their finished bird wants to do a face plant with the wings removed?