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berniew
36 Posts |
 Posted - 02/02/2004 : 12:04:52 PM
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As far as I know I will have the first Mantis in the NW. All I need to do is build it. Thanks in advance for answers to questions I plan to post here.
So far I have received the wings and tail from Phil and the Terry fuse will be here soon. The wings and tail are very impressive. They reinforce my decision not to build them myself because my results vary. Phil’s wings look great!
A couple of questions to get started (I live with the assumption that the only dumb questions are the ones not asked):
1. What is the wing area of the Aegean Mantis wing? I can’t find this anywhere and I don’t trust my measurements.
2. In the other Mantis build thread there is the statement; “I used the TLAR method for alignment on the tail.” I think this has something to do with sighting the trailing edge but I am not sure. What does the acronym TLAR mean?
3. What is the best way to get the alignment pin in the wings correctly? This has always been a puzzle for me. I want to get away from my usual drill and pray method.
Bernie
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Edited by - berniew on 02/02/2004 12:09:36 PM |
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radian
8 Posts |
Posted - 02/02/2004 : 7:13:59 PM
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1) I can't answer...
2) TLAR "That Looks About Right"
3) I used a 1/4" brass tube. Used a dremel to grind out the inside diameter to make the end razor sharp. Then inserted this into the hole for the pin in the root rib and twisted/pressed it to drive it in about 3/4" then pulled it back out. The foam that was in the tube pulled out with the tube leaving a nice clean and accurate 1/4" hole.
Sincerely,
Radian |
Edited by - radian on 02/02/2004 7:21:36 PM |
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berniew
36 Posts |
Posted - 02/02/2004 : 9:39:28 PM
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Radian, Thanks. I think the answer to my first question is 1068 sq in. This from being able to cruise the net at work.
I guess my real question about the incidence pin is my end ribs don't have holes drilled. How do you locate them? I am thinking of making a template of the end ribs then gluing a drill guide where I want the hole, something like piece of steel tube or something. Are there better methods. I want to try to remove human error without having a lot of power tools.
Bernie |
Edited by - berniew on 02/03/2004 2:51:18 PM |
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berniew
36 Posts |
Posted - 03/01/2004 : 2:38:38 PM
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| Does anyone have control set up information for the Aegea winged Terry Fused Mantis? I don’t seem to be able to find this info on the web. |
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berniew
36 Posts |
Posted - 03/05/2004 : 1:36:32 PM
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Some pictures.
I chucked my wing rods into a drill press and wet sanded with 220 grit. This took about 3 hours. If you use the drill press method I recommend 80 grit, 120 at least, then finish with 220. They fit very tight into the center section and less tight into tips (they will slide on an off on the tips). I plan to glue them into the center section to avoid loosing them.
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I was freaking about the pushrods from the front of the boom to the servo tray. I was thinking these would be free-floating making for a very sloppy connection to the tail. I was going to encase the teflon tube in a carbon tube anchored as the front of the boom and the back of the servo tray. See the carbon tube in the following picture.
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I then quite freaking out and looked at the fuselage pod. It is narrow enough that I can glue the teflon tube to the sides for support without bending the pushrod much. This is so simple it plumb eluded me.
Here is my tail top:
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And bottom:
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The tail will be removable, bolted on with 2 6 * 32 screws. I used Jose's bent 4 * 42 wire method for the tail control horns, as I am familiar and comfortable with this method. Those of you with sharp eyes will see the microballon filled epoxy on one side where the control horn goes into the control surface. When I was putting in the second control horn I notice it (and therefore the first) were upside down and had the pull the first one out  Too bad the epoxy was already starting to cure. 
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Edited by - berniew on 03/05/2004 1:38:39 PM |
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berniew
36 Posts |
Posted - 03/29/2004 : 9:59:04 PM
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Pylon build
The bottom of my pylon is ¼ inch aircraft plywood, 2 layers of 1/8 inch because this way there is more and thinner plys. This is glued in with west epoxy mixed with milled plastic fibers and wood flour, the fillet covered with 3 oz cloth. The basswood strips up the side are to add more resistance to the bottom from the pull of the bolt on launch.
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I added a layer of 1/8 inch ply about half way up to stabilize my ballast slugs.
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The top is 1/8 inch ply built up to 3/8 around the bolt to keep the bolt top from moving forward on hard landings. The top here is partially filled with the same mix I use for glue. I will finish this with another layer of 1/8 ply on top of the pylon with any gaps filled with filled epoxy.
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Edited by - berniew on 03/29/2004 10:03:06 PM |
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berniew
36 Posts |
Posted - 05/23/2004 : 3:47:13 PM
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I am on the horns of a dilemma. As you can see my Mantis build is down to the short strokes. I finally have a deadline, a PASS funfly I am hosting Memorial Day. I would like to be able to test fly my Mantis then. The dilemma is, I have just ordered the cross tail parts for may Mantis from Phil as I am afraid my V-Tail has some twist in it. I know I can get it to fly with a slightly twisted V-Tail and with the V-Tail I will have it ready by Memorial Day. But if there is twist it will never fly right as trim will continually change on all axis with changes in speed.
The question is, how hard will it be to change from the V-Tail to a T-Tail? I am thinking I will just need to change the carbon tail control rods and slightly reroute the rods guide tubes. Then I will just need to cut of the V-Tail mount and mount the T-Tail parts. If I set it up for the V-Tail then change to the T-Tail am I creating a nightmare in changing it over from one to the other. Or should I just wait until I get the T-Tail and not do the final set up of the V-Tail? Comments and opinions would be greatly appreciated.
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Phil Barnes
100 Posts |
Posted - 05/26/2004 : 08:19:50 AM
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How badly aligned is your V tail? How exactly is it misaligned? It seems like you might be able to fix the alignment or live with it if the misalignment is slight.
I will assume that the problem is that one V tail half is sitting at a different angle of attack than the other. This would happen if you glued the two tail halves together without carefuly matching the root ends to each other. As long as the two V tail halves are matched to each other then any tail misalignment could be corrected by shimming the tail mount or redrilling/enlarging the bolt holes.
The correct fix is to cut the two tails apart and reglue them at teh correct alignment. I would be tempted to do this with a razor saw. The V tail brace might be a problem if you used it but if you cut everything else loose a firm twist might allow you to break that loose and reset the alignment.
A simpler fix might be possible also. Assuming that one V tail half is sitting at a higher angle of attack than the other; If you simply ream out the forward mounting hole for the V tail mounting bolt such that you can twist the V tail assemby either left or right, that might be all it takes to reset the alignment. This simply means that the center line of the V tail assembly will not be parallel to the centerline of the boom. This slightly "yawed" alignment of the tail assembly could be set just right to exactly compensate for the difference in angle of attack between the two V tail halves. This is hard to describe in text but it is exactly the same as how wing dihedral causes a difference in angle of attack between the two wings when the wing sees a sideslip. You just need to set the V tail on the boom such that you see the same angle of attack on both V tails when you sight them from the front. If the two V tail halves were correctly matched to each other when you glued them to each other then the center line of the V tail will be parallel to the center line of the boom when you set this alignment.
If you need to change the angle of attack (incidence angle) of the entire V tail together then a simple shim between the V tail and boom would do.
The difficulty of switching to cross tails at this point depends on exactly how you installed the pushrod tubes. For the cross tail you need the tubes to be along the sides of the boom (either inside or outside the boom). Read the thread about cross tails for more details, we talked about pushrod installation for cross tails a bit. You would also need to remove any and all of your V tail mounting stuff from the aft end of the boom, hopefully the boom would still be intact or restoreable after doing this.
For the short term I would suggest the simpler fix for the V tail as described above. Later you could do the correct fix for the V tail or buy a new V tail or switch to a cross tail if you don't like the results. Just don't psych yourself into thinking that something is wrong with the model. As long as you can sight from the front and see the same angle of attack on both V tails then all is well.
Phil
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berniew
36 Posts |
Posted - 05/26/2004 : 12:57:54 PM
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Phil, thank you for the long response. The problem with my V-Tail is the two halves are misaligned with each other. If I had glued the tail halves to each other alignment would have been easy, I could have just matched the root ends and everything would have been OK. I put a flat piece of hardwood between the halves as shown in other threads and in my picture above to provide a hard point for the mounting screws. I also used the aluminum brace. The problem I have is I have not been able to figure out how to jig the V-tail halves to assure alignment and wound up using the TLAR method. I find it very hard if not impossible to sight the alignment of the tail because they have no straight lines. I don’t think, the way I built the tail, that it can be cut in half so I could realign it without ruining the tail.
I understand what you are saying about shimming to correct alignment and I will try it. It will be easier to sight the tail installed on the fuselage. I know the side to side alignment and the horizontal alignment with the wing is correct as I could jig both of these. I just don’t want to handicap the performance of my Mantis because of a misaligned tail. I wouldn’t blame the performance on the design if I think there is a building mistake on my part. But this will be my competition ship and I want to be able to extract its maximum capabilities, especially in landing.
If my V-tail can’t be fixed or impedes my Mantis’s performance in any way I have decided to switch to the cross tail. In fact I have already ordered one from you. My reasoning is if I have to rebuild the tail the cost difference between the V and the Cross tail is only $25.00 and with a cross tail alignment is easy. Also, a cross tail is much easier to trim for flying and landing.
I will be testing and perhaps flying in contests with my V-tail this year. If I can’t get it to fly correctly with the V-tail I will switch it to the T Tail, but hopefully not this year. I need to get the plane flying and practice soon to be ready for the 2004 TD and F3J season.
Editorial: I hate the emphasis on ground pounding but in American Thermal Duration contests it always gets down to landing points. One of my motivations for building a Mantis is because of its reputation through all its iterations as a great landing machine.
Bernie
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Edited by - berniew on 05/26/2004 2:22:31 PM |
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F3jeb
103 Posts |
Posted - 05/26/2004 : 2:13:39 PM
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Here is where I am right now. I do find it really difficult to come up with a reliable process. In this attempt I have taken ideas from every one in the ESL I consider might fit my construction style (rushed at best)
1. I initially ordered the tails from Phil with out angles
2. I (Fritz) cut a beveled block of wood with the correct angles.
3. Terry suggested drawing a straight line on the block in order to later align the LE and TE of the tail. (I found it difficult due to the small size of wood and angles)
4. Unable to install Phil’s wire I ended up using a couple of wooden dowels for (spiritual) guide and support
My Plan
5. To glue one side first and align with the line I drew.
6. Glue the other side and use the line as an initial guide but pay more attention to the LE of the first tail
WITH LUCK – I’ll get it in the ball park.
I do wish there was some type of process for this setup that would give consistent results.
I welcome any ideas or suggestions – I plan to start gluing after work tonight.
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Edited by - F3jeb on 05/26/2004 2:16:50 PM |
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berniew
36 Posts |
Posted - 05/26/2004 : 2:37:33 PM
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Jose or is it Fritz, thanks for confirming that V-Tail alignment is a difficult process. You are doing it a little differently than I did and if you can sight the tail I think you will be OK. I did mine with the tails cut to the correct angle and used a rectangular piece of wood. I drilled an oversized hole for the aluminum joiner in the wood figuring I would fill the hole with epoxy. Because I couldn’t figure how to jig the thing I put it together with 5-minute epoxy so I could hold everything in alignment. This made assembly somewhat frantic. When I put everything together one side was slightly lower than the other side. I figured that aerodynamically this wouldn’t be a problem if I could keep the sides in alignment. But my alignment marks were now off and I had to do a TLAR on the alignment. I had no way to put the assembly down so I could step back and sight it and as a result I think the alignment is off. It is close and as Phil said I might be able to shim to make it OK. Stay tuned for flight reports and we will see.
Bernie |
Edited by - berniew on 05/26/2004 2:41:49 PM |
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F3jeb
103 Posts |
Posted - 05/26/2004 : 3:59:26 PM
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It is Jose, I just mentioned Fritz because he was the one who cut the wood for me. I too ended up with one tail a bit higher than the other one.
Jose |
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Fritz
19 Posts |
Posted - 05/27/2004 : 9:57:11 PM
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Jose and Bernie:
The solution is quite simple, really. Look at the pictures Jeff posted on the Aegea Mantis thread started by Anker. Note that the block that I cut for Jose had been shaped on the top to MATCH the top curvature of the tail surface. As long as this curved surface is parallel with the bottom, both tail surfaces should align with the block the same as they align with each other. Its important to make the curve on the top to exactly match the stabilizer. I use a caliper to ensure the parallel-ness of the top to the bottom. Eyeballing it should get within 0.1 degrees, though.
-Fritz |
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berniew
36 Posts |
Posted - 05/31/2004 : 10:22:55 PM
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It’s a keeper!! First flights today, all my fears about the tail being misaligned were false. The plane launches high, thermals easily and lands easily and accurately. Need a little more work trimming, move the CG back a little and getting the flaps to come down 90 degrees (now about 75 degrees) and moving the tow hook back with the cg and other normal tweaking moves.
This is a very impressive plane and puts me on an even keel with the euro moldies.
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Edited by - berniew on 05/31/2004 10:30:13 PM |
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Phil Barnes
100 Posts |
Posted - 05/31/2004 : 11:34:17 PM
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I might suggest leaving the flaps alone. Mine only go down perhaps 60 degrees. Too much flap deployment can get you into trouble with any plane. The more flap you deploy the less responsive the plane is to commands. It is perhaps better to get used to only having a smaller amount of flap travel and just controlling your approach path and airspeed better so you don't need so much flap. I guess this is really just a matter of personal preference. Ninety degree flaps is not necesarily a bad thing if you just drop them all the way down briefly and then partially retract them again well before the final part of the landing approach.
Phil |
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berniew
36 Posts |
Posted - 06/01/2004 : 4:02:46 PM
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| I forgot who said; "If you need full flaps you screwed up you approach." |
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berniew
36 Posts |
Posted - 06/12/2004 : 3:43:11 PM
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Here are some pictures of the plane after it's first couple of flights. As you can see I could do a lot of paint touch up but right now it looks good from afar but is far from looking good which is were I am going to keep it through the summer contest season.
The first picture is of the pylon with the wing mounting bolt and alignment screw in place. Notice that the wing servo plugs are polarized so you can’t reverse them.
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berniew
36 Posts |
Posted - 06/12/2004 : 3:50:33 PM
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Here is the tail servos and switch. The servo mounting plate didn’t have enough clearance for three-pole two position metal switch I like to use so I just glued a JR switch sideways on the tray. The tray has a Kevlar strip epoxied in place over the filled epoxy fillet around the tray. I didn’t want the tray to come loose. I am using 5 Sanyo 1650 cells in a shotgun configuration with on cell on top. I want battery capacity instead of empty weight. I miscalculated how much room this pack would take up and had to grind about 1” off the front of my servo tray. I had two oz of lead stuck to the battery for balance (4 ¼” back from the wings LE), so far I have taken out ½ oz and will probably take at least another ½ out.
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berniew
36 Posts |
Posted - 06/12/2004 : 3:57:34 PM
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Here is a picture of my removable tail, control horns and ball joints. The camera is cruel, it doesn’t look this bad. I locktited the ball joints to the end of the treaded control horn as I don’t want them to come loose. I had to bend the right control horn after assembly to get it to work correctly. You can see the wood inside the tailboom that holds the T-nuts and the wood between the ruddervators. You can also see the hole in the bottom of the boom to access the pushrod connectors. The ruddervators are joined with two layers of 1.2 kevlar top and bottom. Structural filling is done with west system 105 epoxy filled with milled fibers, non-structural fill is done either with micro balloons or West System 410 fairing filler.
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Edited by - berniew on 06/12/2004 4:02:20 PM |
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berniew
36 Posts |
Posted - 06/12/2004 : 4:04:07 PM
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A side view of my removable tail mount. It is very strong and stable. I just needs some paint.
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berniew
36 Posts |
Posted - 06/12/2004 : 4:06:16 PM
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A top view of the tail mount. I paint the places most people see.
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Left Coast Aegea Mantis Build
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