Eagler's Nest
Airframes => Single Seaters => XL => Topic started by: Jeff XL79 on July 27, 2024, 08:03:18 PM
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Finally on the gear. Used rod ends and heim joint for adjustability.
Jeff
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Very nice! What tires are those?
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Hi-run 15 x 6. 2 ply.
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Upper shock
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Tail assembly.
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More tail. Rudder stop.
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Nice work Jeff!
The tread on those tires looks very flat, am I correct to assume the tires were not yet pressured up?
Will the heim joints on the suspension mostly be for camber adjustment?
Did you consider using heim joints on the main gear struts to allow for toe adjustments?
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The tires are a square profile but have low pressure now.
Use of the heim joints does two things. You can adjust camber and they compensate for slight geometry shift when the suspension flexes.
I didn't want joints on the main gear just for weight. Plus they would be tough to install at the swept forward angles i have.
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I didn't really want a square profile tire but I wanted 15 inch at least and 2 ply for less weight. I've seen the turf saver II but it's got guite a bit of tread which would be draggy also. Has anybody found a smooth 15 inch 2 ply?
Jeff
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I found these at Home Depot. Kenda brand does not seem to be available there now, but I did find it on Ebay. Search "Kenda 606-4R-I K401H Rib Tread Tire, 15X6.00-6, 2-Ply". The key to searching online is to include "rib tread" in the search. My photos show tire with 5-lbs air in it.
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The other thing I'm considering is my fuel tank. Reall don't want to build one in the wing. Just looking at how the wing tank would mount kinda makes me wonder if it's supposed to be stressed on the diagonal and single second rib. Plenty of people have done it so i know it works but still looks off to me.
I have a tank that I'm considering. It's a hummelbird tank.
Jeff
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I made my tank from Divinycell foam & fiberglass. It will go in the left wing on three diagonals. Seems to fit nicely. Notice I did not use the metal bracket on the root end of diagonal #1. Les Homan uses a fuselage mounted tank on ORV. He says the CG changes with fuel quantity. ADCO Aviation is going to make a tank in the gap between the wings.
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I dummied up a fuselage tank, but couldn't figure out how to fill it without completely changing the windscreen, etc. Another "issue" is fuel head. You may need to run a fuel pump.
Sure, CG will change with the amount of fuel in it, but stick pressures are light.
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yes you'll have to modify the windscreen for sure here's a side view of Les' if you decide that route... Good luck with this choice... I was planning nose at first, then decided to go to the wing so I wouldn't have this issues you just described & finally (hopefully) decided to put the tank in-between the wings above the fuse & double as wing gap filler too... Hopefully that will work... lol
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Google sonex onex. They have a simular setup yet they fill through the windscreen.
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Between the wing tank is a viable possibility at least for volume.
Tank Volumes
0% Full
Total
Capacity
Filled
Volume*
U.S. Gallons
4.94
0.00
Imp. Gallons
4.11
0.00
Liters
18.69
0.00
Cubic Meters
0.0187
0.0000
Cubic Feet
0.6602
0.0000
I calculated a tank 6.5" x 6.5" x 27".
My actual measurements were 7" deep at the front spar. And 5 7/8" at the rear spar. 27" in-between spars. Adjustments to height so the tank would clear the wing fittings could be made. It would give a tigermoth look to the profile.
Interesting idea. The foam composite tank would be the easiest to make. I'll try drawing it out for a study.
Jeff
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Center fuel tank sketch. Please feel free to give input.
Jeff
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I'll try to get a tiger moth picture for example.
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Tiger moth.
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Yep Jeff - I agree... This is what I've been planning....
https://youtu.be/cVlGuAI3fU8
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Thanks Pappy Adkins. I'll look forward to your ideas..
I was going to order some Divinycell foam to start. Is 1/4" the right thickness for tanks?
Jeff
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I used 1/4" thick Divinycell. It seems very strong once covered on the outside with fiberglass & epoxy. Be sure to use Vinyl-ester resin on the interior. It is much more alcohol resistant than epoxy. All my seams are filleted with a mixture of flox and VE resin. So far, there have been no leaks.
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Nice looking work Kamcoman. I'm excited to try something new. Working with foam and composites has been a goal. I see the vinyl ester resin in the Aircraft spruce book . What outer coating material are you using for the glass cloth? Do we still need to use the home depot drain parts or is there an option?
Anybody have an idea for a sight glass gauge? This will be right over your head so it will need to be electronic or offset somewhere.
The most exciting thing in this design to me is getting the tank outside of the wing. It also centers the weight and makes repairs and service to the tank possible without disturbing the covering.
Jeff
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Following.... Great questions... I was about to ask some of the same... So y'all are looking at buying from ACS?
I thought about getting a gauge, although very affordable, that just seems to add weight & complexity to it, so I'm leaning toward sight glass...
As far as sight glass I'm looking at possibly an 'indented' section with maybe tube at an angle... just don't know till I start whittling away at my foam template....
I so agree with you... I'm super excited to give this a go for some of the same reasons...
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I used the Derakane vinylester resin, 1/4" Divinycell foam, Rutan bi-directional 7725 8.8 oz FG cloth, and flox powder, all from ACS (30 miles away). I already had some Aeromarine 300/100 epoxy from a boat project, but any laminating epoxy should do (not T-88). Be very careful ordering VE resin, it has a very short shelf-life and is expensive. I did not buy mine until the basic box was already glued together with 5-min epoxy. The petcock is from Throttle Addiction and the quick drain is Curtis (ACS). I VE/floxed an aluminum plate in my sump and threaded it for the petcock & drain.
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Ok y'all made me do it...
As I've stated many times before BEAUTIFUL!!! Question looking at the tank it appears the fiberglass will be very clear, right? Just thinking I might leave part of the underside unpainted for a sight window... Of course the rest I'd paint red...
I went out quickly and made a temp mold - will have to make final mold once I get the wings mounted And know my actual clearances...
The 1st pix is side view with my cardboard template
the 2nd from pilots perspective
the last is slightly from lower side
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Yes David, the fiberglass is crystal clear if you use a good epoxy. Here's a photo showing how you can see every detail under the FG.
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Yes David, the fiberglass is crystal clear if you use a good epoxy. Here's a photo showing how you can see every detail under the FG.
I see where you built your sump. It looks like you built it by stacking layers. I assume that you cut out the interior of each layer and coated it with VE . I read in the Aircraft spruce product description that the divinycell was formable with heat but hot wire was not allowed. Have you tried heat forming for any shape adjustment?
Do the plates get any special surface treatment or are 5hey glued to the surface then glassed over?
Thanks for showing your work Kamcoman.
Jeff
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You are correct about stacking layers to form my rear sump. The plates are glued into the foam with VE resin and flox, then glassed over. I did not need any curved surfaces except the top and it was such a gentle curve no heat was needed.
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@kamcoman77
How did you do the VE/flox when installing (closing) the top of the tank?
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Brock, I put a 1/2" wide bead of VE/flox mix along the inside edge of the top. I made a slightly more liquid mix and put a generous bead along the top edges of the box, and a bead on the inside of the box touching this. I taped the top to the box and turned it upside down. I carefully banged the whole assembly on my workbench letting gravity force the beads together. Then scraped most of the excess off the outside except for what was under the tape (2nd pic). I don't have any photos of the VE/flox beads before assembly but in the 2nd pic you can see how much VE/flox squeezed out. The excess that was under the green tape had to be ground off with a sanding disc.
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Finally got the seat built. Used webbing and large headed rivits. Each webbing can hold 1500 lbs. Ends where rivit goes through are double and triple layers at the rivit. It's very comfortable and I don't think it'll give me the dreaded waffle butt.
Jeff
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I'm working on the control stick. My aluminum piece is 1" .058 wall. My steel 1" 1/8 .035 is very sloppy over the aluminum. I'd really like to shim it up so I'm not just hanging on by rivits only. A nice snug fit would be stronger and safer. What's your thoughts eaglers?
I'm trying to avoid paying Aircraft spruce shipping for another piece of 4130 that would fit better. I've got some nice shim material but wanted to find out if anyone else has this concern.
Thanks
Jeff
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I don't have the plans in front of me nor have I yet looked into this but. Is the 4130 tube the control stick that goes over the aluminum at the pivot? If so, can you split the tube a few inches lengthwise with a relief hole in the end then bolt through so as to make it clamp the aluminum.
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(scratching head)There's no steel tubing on the control stick?
(https://static.imgzeit.com/large/2fe32cb30ef9e68a/20221209_153705.jpg)
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I'm assuming you're talking about the tube that makes up the pivot on both ends... If so, the front one you'l take a slice out of it anyways for the pulley... the rear one, you'll be welding on the control horn as well - after you weld the arm on, see how it slides on... you could always split it and re-weled it if you had to... I welded a sleeve on top for a guide (you can check it out in the video @ about 4:25); but it slid on just right with no issues...
https://youtu.be/l78wB1cUfHY
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Thanks Pappyadkins, that was what I was asking about. I should have called out the specific part of the assembly. I'm going to call it the aileron torque tube assembly. I like the idea to split and weld the steel sleeves. I'll just use some scrap 1" 4130 to slip inside the 1 1/8" to ensure diameter and also to heat sink it. It should TIG up nice.
Jeff
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I've been trying to come up with a solution for a center mount fuel tank. So far everything that has made it to mock up looks like crap. With the tank humped up to give enough volume the resulting look is really bad. I think it would be a drag inducing shape with a case of the uglies. The only other option that would make it possible would be to add width to the wing mounts. That in turn adds weight and requires adding width to the struts, cables, center cover plus mount supports.
I really don't want to widen the wing mount. It stretches the mount out in a way I don't like. This mod is abandoned.
I'll be figuring out the next steps for a wing tank. I don't like it and may still opt for the cowl but the center tank is out.
The wing location will require some additional structural additions also in order to carry 30 odd pounds. I'm leaning toward beefing up the second rib in to be like the root. Adding .8mm ply around the bay and thin aluminum angle around the base for support. I can stiffen the divinycell sides and bottom with thin carbon sheet.
I gotta say, the fuel tank has been a challenge to get from the plan to reality in a good way. Plenty of people have done it well but it's going to be custom regardless.
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I saw, a while back, a picture of an ultralight with small pontoon looking tanks mounted one on each strut sets.
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Rudder pedals are done. Just used a strap of .090 4130 for some extra contact area. Home Depot aviation springs also seen on screen doors. Cable guides and turnbuckles to the rudder also complete.
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Control stick done. Just need castle nuts for the pivots.
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looking good...
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I thought about the center mount fuel tank myself but in the end I did not do it and glad I did not try. The main issue for me not doing a center mount fuel tank is access to the wing pins! I have a trailer setup and I mount and dismount the wings every time I go flying (no hanger near me). I have issue getting the pins in when I have 4 or 5 inches of room between the wings - I would hate to deal with something that had less and no access but from the bottom or something like that. I think the best approach is just to build the CE that has room for tank. I actually find the weight in one tank in the wing is just not an issue, I cannot feel the wait on the tank side when I am flying and I find it is easy enough to drain the tank after a flight. I use a quick connect fuel connector between the tank and the fuselage line going down to the engine. The quick connect I use seals the lines when disconnected, I then connect a drain hose that drops down to one of my fuel cans. By the time I take off the non-tank wing the fuel has all drained and I can then take that wing off. BTW, my trailer is all rigged up to move the wings in and out so easy one man operation - something like what Les does.
Awesome job on the fuel tank!!
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Nice work Jeff! I have to ask though, am I the only one stressed out at not having dimensions on what would seem to be important stuff like control stick bolt hole locations? I'm ok with "close enough" on kitchen cabinets, etc, but for something that will fly I find this less than ideal. Maybe I should seek counseling or something......
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Jon, I split the distance from the seat front to the pulley... 4" each way & I have plenty of movement for the elevator...
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Leonard knew there was enough variables that in certain spots making a mock up was going to be the only solution. When I built mine there was string and duct tape involved.
The practice of mocking up and verification should have been my method from the beginning. For example, the landing gear angle and geometry needs to be built using the actual fuselage measurements and calculated wing leading edge location. With a plumb bob and a level fuselage you can then determine axel position and actual forward angle degree. 12° is an approximation.
Study the plans, make mock ups, stick to conventional methods.
Jeff