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Lowrider LSA

What is the thing in the upper left and all them switch looking things? And why a Hobbs meter in an experimental?
 
Don,

Upper left is defrost...that will split with floor or give full heat to the windshield to get rid of the frost depending upon how hard I pull it. It doesn't freeze where you are, eh? Those switch thingys are for oning and offing stuff like lights and other stuff... the breakers are eye candy unless there is a short somewhere. Hobbs is for engine time since I only log required time. I've outgrown the idea of "building time" awhile back.
 
Hobbs is for engine time since I only log required time. I've outgrown the idea of "building time" awhile back.

But... Isn't that an "engine monitor" cut-out on the right? Most of those have a tach that records time, which is probably the better way to track maintenance, anyway... Why not just use that? Check out the EI CGR-30P for engine monitoring. It's pretty incredible.
 
How about one of those USB charging ports? I can't remember the name, but it has "blue" in there somewhere. See it in AvWeb all the time...
 
If you only log "required time", that's flight time (T/O to landing). That's what is required for maintenance. A Hobbs won't give you that, just total engine run time. Put a clock in that hole and leave the hour meter on the bench.
 
Good idea but I have one on each side under the panel along with a "cigar lighter" plug. They work great to keep pads or phones charged. One of those silly breaker and switch controls them so I don't leave something plugged in and run the battery down.
 
You're right Wrong! But the numbers are close enough to do oil changes. Actually, I think it will provide the time power is provided to the Hobbs but that is pretty close to engine time.
 
I haven't been ignoring airplanes, just haven't been working on the LSA. I pulled the wings off my Challenger and brought it back to the shop for a Winter "pickling" and checkout for next year and helping a friend with an annual on his plane.

Still looking for land to build on so I can have a smaller house and bigger shop that will more easily be know in some parts as a hanger...for the county...it's gunna be an equipment shed...maybe 50'x80' and a big door on one end. You'd think Idaho would have some vacant land that was for sale but nothing that will make a runway or that I can afford. Went to look at 40 some acres today and it would have done just fine but my wife reminded me that I could rent hanger space at SZT for maybe 50 years for the price of the land...she clearly doesn't understand.
 
Around these parts, the situation is a bit different. With rural land selling for anywhere between $2K and $10K per acre (depending on how far out you go), and much of it reasonably flat, it would be pretty easy to justify buying land for a runway / hangar versus renting a hangar... However, SWMBO does NOT want to move because we're on a great piece of property with great neighbors 1/4 mile away. Honestly, I don't really want to go through all that again either...

All the local airports that have rental hangars have huge waiting lists, and they can (and do) charge ridiculous rents. I'm paying $650/month for a 50 ft T-hangar (all that was available) at an airport 20 minutes from the house. With a 7,002-ft paved runway, it's nice for my current Rockwell Commander 114, but definitely "overkill" for my "work in progress" Bearhawk Patrol. It will probably use about 250 feet of that runway!. But at least we have a great tower crew, nice FBO, and pretty good maintenance shop on field. They just put in self-service fuel, although they're still getting the permits in place and haven't turned it on yet.
 
Your wife is right Jim...I don't want to move either but my house is two times too big and the shop is half what I need/want. My wife says unless we adopt 3 kids we don't need this house so I have her convinced since we both agree we've raised enough kids.

I want 1,500 feet next to Forest Service land with no trees on either end and facing West into the wind...house must have Southern exposure and it can't be too close to the railroad tracks...I don't want much but it ain't easy to find up here. Texas is a great place to visit...love the bbq, chili and brisket!!
 
I think this has been discussed before, but I'm getting close to covering my flaps and wanted to ask it again.

I'm thinking it would make sense to cover them with 0.015 2024 rather than fabric...at least in the prop blast area. They are 8'-0" long and have 3 pretty hefty hinges with the control rod in the middle of the flap and I'm concerned that the inner portion of the flap will be stressed when it is down in the 50 degree position. I think the alum will be more rigid or stiffer and would resist twisting more than a fabric covered flap. Another option might be to put 0.020 2024 on the bottom of the flap to stiffen it and then wrap the flap with fabric so it will match the aileron better.

Any thoughts or other option will be appreciated!!
 
Any thin gauge aluminum in the prop blast is more susceptible to cracking than is fabric. What was the flap originally designed to be covered with? Use it.
 
The wing did not have flaps originally so I have nothing to follow. I'm guessing the flexibility of fabric is a good thing and making them more rigid which might lead to cracks would be a bad thing. Do you think flush riveted 2024 will crack because of vibration when the flap is deployed? I don't want to go to heavier material than 0.020" so the next best option would be fabric to keep the weight down.
 
You raise several questions. I have no idea of how your structure is designed. Will it take the twisting loads over the unsupported 4 foot span from the push rod without the aluminum skin? If so fabric. If not sheet metal. The .015" or .020" is thin, so will require each hole to be dimpled for countersunk rivets. It would be a good idea to use an adhesive to supplement the rivets in order to prevent the vibrating thin skin from cracking at each rivet.

How many degrees of deflection do you plan on using? Once this exceeds about 30 degrees the loads go up exponentially requiring extreme control forces for full flaps. These forces will be concentrated into the one actuator. I would suggest two push rods assemblies evenly spaced along the flap.
 
Sky,

Here's shot of the flap. You may recall we tweaked the design some to get a good air flow over the top of the flap when down. The flaps can go down to 50 degrees but I suspect that will be rarely used for normal flying. Probably 30 degrees or less and I'll have 4 notches, 10, 20, 30 and 5o degrees. It easily could be limited to 40 degrees.

I have some Proseal in the refer or maybe 5200 that I can use to stick the alum together before riveting. That would also kill a lot of the vibration from prop blast. I think the left flap gets most air from the up swing of the prop.

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I'll try again more briefly.
Fabric.
Reinforce end ribs against fabric buckling.
Swap 2L & 3L nose ribs in order to buck rivets.
Be sure to extend top wing skin to close flap gap when up.
Don't forget lazy "S" skin between top trailing edge and lower spar cap for smooth air flow.
Be sure that the push rod attachment mechanism in wing is very STRONG.
Flap handle is long enough to give mechanical advantage to move flaps to 50 degrees. And equally important to retract in flight on a go around.
Leading edge skin will take the twisting loads.
 
That's interesting...my post prior to the above one also disappeared...maybe we've been hacked. I'll copy this one in case it happens again.

Good info Sir!

I'm thinking of using stainless sheet metal screws to attach nose skin at the hinges and push rod locations so I can remove the covers I'll make to fill the area around them...otherwise I can't get to the inside to adjust if necessary. I guess nut plates would be better.

The push rod and hinge mounts are doubled 0.063 riveted inside to the 0.032 front and rear spars. The flap handle is about 3' long now but will be cut down once it is installed and I can find out what length will be comfortable to use and have no interference with cabin stuff.

Roger on remainder.
 
Remember that the leading edge skin in the "D" shape when riveted to the nose ribs will be the primary box spar structure for the entire flap. All of the air loads will be passed through the fabric to the trailing ribs to the box spar. If the LE "D" skin is not continuous for the entire length, the flap will be more flexible with the possibility of cracks forming on the spar at the cutout locations. Make those hinge openings as small as is possible for access. A cover can be made which will tuck under at one end with just one screw at the other to hold it in place.

Try to follow the load paths in your mind to see where they go and what interrupts that path. With careful thought you will not have to go in afterwards to readjust the hinges. The only adjustment may be to the length of the push rod. The hinges are all outside of the flap.

Remember that stainless against aluminum is a dissimilar metal which can cause corrosion. Separate Stainless from aluminum with a thin plastic or aluminum sacrificial washer. May not be as important in Idaho as it is here near the coast.
 
The way I pictured in my mind the flap nose skin was one piece with cut outs for access and make a plastic cover that would expose the minimum necessary to try to keep insects, mud and stuff out of the hole. Would it make sense to put a backer piece of 0.025 to beef up that area?

Only salt I have around here is on baked potatoes...'less you go south to the Great Salt Lake or fly West to liberal land...sorry...couldn't resist.
 
Sky,

Is just adding a second layer of the same material (0.020) around the hole adequate? I can rivet it on top and still countersink the rivets.

I'd like to wish everyone a Merry Christmas and Happy Holidays and the hope that Santa will fill your stocking with things of JOY!!!
 
Low,
Place another piece under the flap at the actuator opening similar to the top piece which you have. It doesn't need to be as wide (chord wise) as the piece which you have on top. These two pieces need to be riveted to the spar cap. This will stiffen the spar at the push rod cutout where the highest twisting loads will be by carrying the load across the cut. It doesn't look as though you will need to make any cut out at the other two hinge points.
 
That makes sense and should be easy to accomplish. I'm thinking the aileron push rod should get the same treatment even though it isn't getting the same leve of stress..THANKS!
 
Quick question for you carbon fiber experts...will a band saw with a 24 TPI blade cut carbon fiber pieces cleanly with only minor sanding necessary? Is there a better way to cut it? Also, is there a need to chamfer holes drilled in carbon fiber tube?
 
Why I need a bigger shop...power steering pump died and we fixed it, then a hyd hose on the loader split and gave me a shower with hot oil which we fixed. Now I'm waiting for the next thing to go on the tractor...clutch needs to be replaced but I'm babying it and hopefully it will last until shorts weather. Hopefully, we won't get a snow storm like the East Coast is scheduled for this weekend!

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2 airplanes, a busted up tractor, an 18 foot table with most of a wing on it and an 16' covered utility trailer being converted to a little hunting camper, my bow range and of course lots of stuff that goes into a shop...I need a bigger shop for sure. I'll be back on the plane soon...I promise!!
 

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Hmmm...never realized how bad my tractor looks. I had a stump from a 36" oak tree fall on the front end after rolling out of my loader bucket. It could have come out the back of the bucket and fell on me so I guess I'm happy that it went that way.

Question for all you aero experts... I extended my ailerons from the flaps to the wing tip (8'-0") which will increase the amount of air flow affected by aileron deflection both up and down. I did so to get more low speed roll control. Is there a formula to determine how much deflection there should there be in each direction based upon the area of the aileron? I want fairly sensitive response but not too "touchy" at higher speed. Also, I'm planning to put an auto pilot on there so that will also be affected. Any thoughts?
 
OK. guess there is no thoughts. I'm going to proceed with the deflections noted in the plans (23* up and 18* down) and I'm pretty sure I will need to change the aileron bell crank ratio to give that amount of movement with stop to stop movement of the control stick. I believe if that is too much movement for the larger ailerons I can easily put "stop bolts" in place to limit aileron movement. Unfortunately, I won't be able to tell if the deflection is too much until I fly some. It would make sense to put in the capability to limit movement while I'm building the bell crank although I could limit the movement at the control stick end but it seem better to do it at the aileron control end. We'll see.

Another question...has anyone used these posts on the site in place of their construction log? I just noticed a recent comment in the "ask a DAR" portion of Kitplanes magazine that there is no specific requirements for how a log must be constructed. I have a log but it is becoming pretty ratty and my other problem is when my last computer killed the hard drive all my pictures were lost. Just a thought and wondered how other builders have handled their log?
 
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