Sig Kadet LT-25 build.
08-29-2010, 10:55 AM
#26
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RE: Sig Kadet LT-25 build.
ORIGINAL: crash bandicoute
for the wing mounting, if you haven't already figured something out, you could use something like this on the aft part of the wing. it will keep clear of your aileron linkages, should you decide to use the single servo method. i used the basic same idea, only mine is utilizing little 1'' blocks, instead of these. they would, of course, be mounted to the sides of the fuse and all you would have to do is drill the holes in the trailing edge of the wing to insert the bolts through. then cut off the eccess of the bolts so they wouldn't stick way down in the fuse. i agree with the twin dowel on the leading edge, also. i have an RV-4 as well, and on the leading edge of the wing is just a tab that inserts into the fuse a little. should be good enough, but why not have the added insurance.
http://www3.towerhobbies.com/cgi-bin...?&I=LXE099&P=0
for the wing mounting, if you haven't already figured something out, you could use something like this on the aft part of the wing. it will keep clear of your aileron linkages, should you decide to use the single servo method. i used the basic same idea, only mine is utilizing little 1'' blocks, instead of these. they would, of course, be mounted to the sides of the fuse and all you would have to do is drill the holes in the trailing edge of the wing to insert the bolts through. then cut off the eccess of the bolts so they wouldn't stick way down in the fuse. i agree with the twin dowel on the leading edge, also. i have an RV-4 as well, and on the leading edge of the wing is just a tab that inserts into the fuse a little. should be good enough, but why not have the added insurance.
http://www3.towerhobbies.com/cgi-bin...?&I=LXE099&P=0
That's a good tip crash and I'm glad you suggested it. Having the rear wing mounts fastened to the sides of the fuse will eliminate any clearance issues with the single servo set up and the F3 former doesn't look strong enough since it's made of balsa on this plane.
Great suggestion! Thanks!
08-29-2010, 11:19 AM
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RE: Sig Kadet LT-25 build.
I jumped back to the wing and guys, I am very glad I strayed from the instructions and didn't sheet the underside of the leading edge before joining the wing halves. Since I took out almost of the dihedral, the ply wing joiner was useless. So I had to make a new one and as any kit builder will tell you, save all your scraps! 
I used two pieces of 1/16" lite play laminated and made a new one and it turned out to be ~ 0.020" thicker so I had to go in and open up the slots in the ribs. If I had sheeted the wing beforehand, I'd be in trouble.
In a few minutes it should be dry and Ill know how much dihedral I ended up with.
I used two pieces of 1/16" lite play laminated and made a new one and it turned out to be ~ 0.020" thicker so I had to go in and open up the slots in the ribs. If I had sheeted the wing beforehand, I'd be in trouble.
In a few minutes it should be dry and Ill know how much dihedral I ended up with.
08-29-2010, 02:22 PM
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RE: Sig Kadet LT-25 build.
the plane's looking good. since the dowels would usually go through the fuse sides, they should be sufficiently strong enough for the wing mounting hardware. i would make sure they are through a doubler or reinforcement, and then epoxy them as well, since the screws for the mounts are kind of small. good catch on the spar doubler. who needs to follow instructions, anyway? that gets boring. just remember... a little more rudder throw, for reducing the dihedral.
08-29-2010, 03:54 PM
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RE: Sig Kadet LT-25 build.
maybe it was somewhere else i saw it. not in the sense that you need to make the rudder bigger. when you take away the dihedral of the wing, it lessens the effects of the rudder when you go through a turn. thus you should increase the throw of your rudder, or if you have a lot of throw already, you may be utilizing it that little bit more. but don't go building an over sized shark fin sticking out of the back of your plane. just be a little more cognicent of using it. i'm sure you've been flying for a while, when you get good enough flying a trainer, you begin to get , how should i put it, arogant with your ability, and when you can knife edge a trainer, keeping it from pitching or rolling or decendingwhile you do it, that's goodsurface use. because of the flat bottom wing and producing a ton of lift, you have to pay attention to all of your surfaces. that's from an old fart i like to call grandpa. flying since the 70's, i believe. so i pay attention to him when we talk about the planes.
08-29-2010, 04:02 PM
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RE: Sig Kadet LT-25 build.
i forgot to mention with the wing mounts. mount them so the top of the mount is flush with the top line of the wing saddle and put a dab of white paint or whatever color on the top of the mount, so that when you sit the wing down in place, it "marks" the bottom of the wing where you need to drill the hole. instead of the hit and miss, and you get it perfect the first time around. then before you cover, put a 1/16 square piece of ply over the wing trailing edge to brace it a little better so your wing doesn't get indentions where the bolt heads are screwed down at.
08-30-2010, 05:02 PM
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RE: Sig Kadet LT-25 build.
ORIGINAL: crash bandicoute
maybe it was somewhere else i saw it. not in the sense that you need to make the rudder bigger. when you take away the dihedral of the wing, it lessens the effects of the rudder when you go through a turn. thus you should increase the throw of your rudder, or if you have a lot of throw already, you may be utilizing it that little bit more. but don't go building an over sized shark fin sticking out of the back of your plane. just be a little more cognicent of using it. i'm sure you've been flying for a while, when you get good enough flying a trainer, you begin to get , how should i put it, arogant with your ability, and when you can knife edge a trainer, keeping it from pitching or rolling or decending while you do it, that's good surface use. because of the flat bottom wing and producing a ton of lift, you have to pay attention to all of your surfaces. that's from an old fart i like to call grandpa. flying since the 70's, i believe. so i pay attention to him when we talk about the planes.
maybe it was somewhere else i saw it. not in the sense that you need to make the rudder bigger. when you take away the dihedral of the wing, it lessens the effects of the rudder when you go through a turn. thus you should increase the throw of your rudder, or if you have a lot of throw already, you may be utilizing it that little bit more. but don't go building an over sized shark fin sticking out of the back of your plane. just be a little more cognicent of using it. i'm sure you've been flying for a while, when you get good enough flying a trainer, you begin to get , how should i put it, arogant with your ability, and when you can knife edge a trainer, keeping it from pitching or rolling or decending while you do it, that's good surface use. because of the flat bottom wing and producing a ton of lift, you have to pay attention to all of your surfaces. that's from an old fart i like to call grandpa. flying since the 70's, i believe. so i pay attention to him when we talk about the planes.
I was warned about about moving up from a trainer too quickly and the guys were right. After a 4* 60 and .40, I think I have come full circle and want to get back to the simple slow/relaxed flying in a semi scale format.
Question about the rudder though. Would adding a 1/4" tri stock to the leading edge of the rudder be ok?
08-30-2010, 05:27 PM
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RE: Sig Kadet LT-25 build.
i know changing the shape of the trailing edge of your surfaces effects the airflow coming off them in a negative way. again reading somewhere else, the best for your surface trailing edges, is fully tapering them, as on a real aircraft. less efficient than that, would be leaving them squared. the least efficient is rounding them. now regarding the leading edge, i honestly don't know. all the kits i have built, have the L.E. of the surfaces, NOT the fin or stab, shaped down to a point, and the hinges slit into the center of them. the triangle stock in my mind, would only increase the size of the surface itself a minute bit.i round mine all the way around; L.E. and T.E., just because i like the look of it better than squared, and tapering the trailing edges is just a bit much for me. i don't get to fly enough or hard enough to notice the difference. i imagine that if you put the long edge of the triangle stock against the surface, like the sharp part of a knife, it would be okay. i'm not sure how it would effect flight, though.
08-31-2010, 05:35 AM
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RE: Sig Kadet LT-25 build.
Can you post some more close-up photos of the engine installation? I am doing this now and I found the FS-30S throttle tricky to access with the stock engine mounting beams. How did you do this?I got a different nylon mount (Irvine) to see if it provides slightly better access to the throttle lever, but it will force me to move the engine forward about 1/2 inch which I do not want to do as the FS-30S is already slightly overweight.
Also - presumably you switched the orientation of the throttle servo to match the four-stroke carb location, on the left side?
Any help much appreciated - QJ.
Also - presumably you switched the orientation of the throttle servo to match the four-stroke carb location, on the left side?
Any help much appreciated - QJ.
08-31-2010, 05:39 PM
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RE: Sig Kadet LT-25 build.
Well, I cant find my camera so I can't help you right now QJ. Seems like Housekeeping lifted it. I'm waiting to hear back from the property manager now.
09-01-2010, 06:49 AM
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RE: Sig Kadet LT-25 build.
Biff,
Iam committed to the engine mount now
and Ihave installed the firewall and boxed in the fuselage. Icut the Irvine mount down a bit to allow closer engine fitting and got the weight down to 35g, compared to 45g for the stock SIG 2-piece beams. Idid consider the OS mount but Ithink Imay need something more 'giving' in the event of a nose-down landing.
As the throttle is on the left side Iwas planning to invert the servo tray (top to bottom), so that the elevator and rudder servos are unchanged but the throttle servo would then be on the left side, leaving room for the on/off switch on the right side. Then, the throttle linkage will run downthe left side of the tankand out through the firewall just to the left of the engine mount.What do you think? How far did you get with this? I'll post my photos tonight.
Good luck with your build!
QJ
Iam committed to the engine mount now
and Ihave installed the firewall and boxed in the fuselage. Icut the Irvine mount down a bit to allow closer engine fitting and got the weight down to 35g, compared to 45g for the stock SIG 2-piece beams. Idid consider the OS mount but Ithink Imay need something more 'giving' in the event of a nose-down landing. As the throttle is on the left side Iwas planning to invert the servo tray (top to bottom), so that the elevator and rudder servos are unchanged but the throttle servo would then be on the left side, leaving room for the on/off switch on the right side. Then, the throttle linkage will run downthe left side of the tankand out through the firewall just to the left of the engine mount.What do you think? How far did you get with this? I'll post my photos tonight.
Good luck with your build!
QJ
09-01-2010, 07:17 AM
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RE: Sig Kadet LT-25 build.
QJ, the problem with having the switch on the right side is getting fuel into it from the exhaust. It could short out or something.
09-01-2010, 03:21 PM
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RE: Sig Kadet LT-25 build.
mmm good thinking.
Are you going to route the throttle linkage round the tank from right to left then, using the original servo location?
QJ
Are you going to route the throttle linkage round the tank from right to left then, using the original servo location?
QJ
09-01-2010, 04:47 PM
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RE: Sig Kadet LT-25 build.
ORIGINAL: QJ
mmm good thinking. [img][/img]
Are you going to route the throttle linkage round the tank from right to left then, using the original servo location?
QJ
mmm good thinking. [img][/img]
Are you going to route the throttle linkage round the tank from right to left then, using the original servo location?
QJ
As of right now I plan on leaving the servo tray as it shows in the plans but Ill flip the servo around so the horn is closer to the left side. With a Du_bro 6 oz rectangular tank there is plenty of room to run the throttle cable around the left side on the tank without any binding. I'm also doing something different than you. I flipped my throttle arm to face up and notched the firewall from the hatch down instead of drilling a tight hole for the outer cable casing. The reason why is a lengthy topic based on past builds when using 4 strokes and the arm being so close to the firewall.
Ill bring my work camera home tomorrow and show why!
Maybe!
This may not be a problem with this kit.
Edit: After looking at your set up again, you should be ok. The throttle arm is pretty far away from the firewall.
09-03-2010, 03:03 PM
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RE: Sig Kadet LT-25 build.
This is my set up QJ and it's far from perfect. Ill most likely end up using the second hole and trimming back on the hatch.
09-03-2010, 04:30 PM
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RE: Sig Kadet LT-25 build.
I got a little more done and just a warning for the perfectionist around here, this kit doesn't even have a clear windshield so I'm not going to worry about the looks much. And I plan on it being my "beater" plane. So I have no intention of adding a lot filler and spend the next 3 months sanding the darn thing. [:'(]
I got the twin dowel wing mount done up front and it came out ok after a bunch of trimming but I didn't like the gap up top in between F2 and the LE of the wing, so I added some 1/4" tristock to fill it in.
I got the twin dowel wing mount done up front and it came out ok after a bunch of trimming but I didn't like the gap up top in between F2 and the LE of the wing, so I added some 1/4" tristock to fill it in.
09-03-2010, 04:43 PM
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RE: Sig Kadet LT-25 build.
Looks ok to me. 
Ihave glued the throttle pushrod tubing at the firewall now (step 70) so keep your fingers crossed. Tomorrow I'll connect everything together and check for smooth movement. You're right about the tank - Igot a cheap 6oz rectangular tank from LHSand there seems to be plenty of room to bend the throttle round the sides. I could keep the servo positions and just flip it round 180deg.
One other thing - Iam considering adding some more stick balsa (maybe just 1/8" square)in the corners of the fuselage between F3 and F6. Rationale for this is
nce the corners are sanded round, Ireckon there is not much material left in the tail section, given the enormous cut-outs. And at least one person mentioned snapping the tail on landing. Maybe this is worth adding 0.2-0.3 oz balsa?
I'l post some photos on Sunday or Monday hopefully. Good luck!
Ihave glued the throttle pushrod tubing at the firewall now (step 70) so keep your fingers crossed. Tomorrow I'll connect everything together and check for smooth movement. You're right about the tank - Igot a cheap 6oz rectangular tank from LHSand there seems to be plenty of room to bend the throttle round the sides. I could keep the servo positions and just flip it round 180deg.
One other thing - Iam considering adding some more stick balsa (maybe just 1/8" square)in the corners of the fuselage between F3 and F6. Rationale for this is
nce the corners are sanded round, Ireckon there is not much material left in the tail section, given the enormous cut-outs. And at least one person mentioned snapping the tail on landing. Maybe this is worth adding 0.2-0.3 oz balsa?I'l post some photos on Sunday or Monday hopefully. Good luck!
09-03-2010, 05:01 PM
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RE: Sig Kadet LT-25 build.
ORIGINAL: QJ
Looks ok to me. [img][/img]
I have glued the throttle pushrod tubing at the firewall now (step 70) so keep your fingers crossed. Tomorrow I'll connect everything together and check for smooth movement. You're right about the tank - I got a cheap 6oz rectangular tank from LHS and there seems to be plenty of room to bend the throttle round the sides. I could keep the servo positions and just flip it round 180deg.
One other thing - I am considering adding some more stick balsa (maybe just 1/8'' square) in the corners of the fuselage between F3 and F6. Rationale for this is: once the corners are sanded round, I reckon there is not much material left in the tail section, given the enormous cut-outs. And at least one person mentioned snapping the tail on landing. Maybe this is worth adding 0.2-0.3 oz balsa?
I'l post some photos on Sunday or Monday hopefully. Good luck!
Looks ok to me. [img][/img]
I have glued the throttle pushrod tubing at the firewall now (step 70) so keep your fingers crossed. Tomorrow I'll connect everything together and check for smooth movement. You're right about the tank - I got a cheap 6oz rectangular tank from LHS and there seems to be plenty of room to bend the throttle round the sides. I could keep the servo positions and just flip it round 180deg.
One other thing - I am considering adding some more stick balsa (maybe just 1/8'' square) in the corners of the fuselage between F3 and F6. Rationale for this is: once the corners are sanded round, I reckon there is not much material left in the tail section, given the enormous cut-outs. And at least one person mentioned snapping the tail on landing. Maybe this is worth adding 0.2-0.3 oz balsa?
I'l post some photos on Sunday or Monday hopefully. Good luck!
09-03-2010, 05:22 PM
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RE: Sig Kadet LT-25 build.
Thanks for posting the photos of the dowels in the wing. I wasn't quite sure how that part was done when you were talking about it. Looking good.
09-03-2010, 05:55 PM
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RE: Sig Kadet LT-25 build.
ORIGINAL: wazzbat
Thanks for posting the photos of the dowels in the wing. I wasn't quite sure how that part was done when you were talking about it. Looking good.
Thanks for posting the photos of the dowels in the wing. I wasn't quite sure how that part was done when you were talking about it. Looking good.
Thanks, but I didn't show how I did the support in the rear for the dowels. Just add a chunk of wood back there. Pretty simple to figure out.
09-03-2010, 07:03 PM
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RE: Sig Kadet LT-25 build.
Yeah. I'm wondering if it is worth building my LT-40 with a bolt down wing. Considering it is my first build (sort of), I don't know whether I should bother? If I do, I will have to investigate a bit more on how to go about it. I'm just not real keen on the look of lacky bands holding the wing on. I had no idea how or where the dowels you were talking about went? So your photo gave me a pretty good idea of how it works? The dowels pretty much lock the front of the wing into the fuselage yeah?