Skymaster Mig-29 OVT Single with S-bus Build
11-03-2013, 05:49 AM
#55
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Join Date: Jun 2007
Location: modiin, ISRAEL
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11-04-2013, 07:03 PM
#57
My Feedback: (11)
After some thinking it looks like I will be using sbus too. I decided to do this instead of using a powerbox, but I can run 2s lipos on the HV servos and the RX is rated for a 2s lipo. The standard futaba 14 channel rx is only rated to 6V and that really chaps my butt when they offer HV servos and no powerboxes.
Reasonably this model can use 9 channels if the ailerons,flaps and rudders are on a Y cable and the servos programmed to be reversed from each other (except for rudder). My elevators will be on opposite channels as I plan to use them as tailerons when the gear is down.
1: aileronX2
2: elevator1
3: throt
4: rudderX2
5: gear
6: flapx2
7: steering
8: elevator2
SBus:
9 - Brake valve
10-14-reserved for future use.
Reasonably this model can use 9 channels if the ailerons,flaps and rudders are on a Y cable and the servos programmed to be reversed from each other (except for rudder). My elevators will be on opposite channels as I plan to use them as tailerons when the gear is down.
1: aileronX2
2: elevator1
3: throt
4: rudderX2
5: gear
6: flapx2
7: steering
8: elevator2
SBus:
9 - Brake valve
10-14-reserved for future use.
11-04-2013, 07:52 PM
#58
I forgot, is yours non OVT? I have the 18mz, using sbus, I think every channel is separate. 3-4 channels directly into the Rx, then one sbus wire down the middle that innvervates lol, first word that came to mind, but its apropos... the back end with all the hubs. I used two regs, one with two leads coming out powering two hubs in the back, and one directly to the rx. I wish futaba would make a better variety of hubs. you can truly only get two servos out of each additional hub if you are sending signal to one, and powering that hub.
essyou, make sure you put in a condition in to disable the steering once the gear is up... no room for the nose wheel to turn in the wheel well.
essyou, make sure you put in a condition in to disable the steering once the gear is up... no room for the nose wheel to turn in the wheel well.
11-04-2013, 08:37 PM
#59
I'm going to use my 9ch 9303 no ovt system just twine turbine and surfaces ,and if I going 3D just fly mine eurofighter it's just better design for the thrust nozzle and some gyros the mig should stay light it's possible and twine for good vertical performance with those big elevators and delta mix the jet should do just fine with basics acrobatic ,so me just one fuel tank one uat 9ch power safe rx two 2s2500 mah life and one 4000 mah 3 s life for turbines + two vt80 straight in the back no pipes if possible ,that waye will make the jet at least 4-6 lighter than big single turbine and ovt pipe +4extra servos.
12-20-2013, 10:32 AM
#60
An update. I am coming to the conclusion that this airplane is cursed. I can't count the number of issues I have experienced. The most current dilemma was the 180RX and the pipe. Skymaster originally sent me the non OVT pipe, I did not want to deal with trying to get another one from them. I asked tam to make one. Sebastian (sysiek here on RCU) was gracious enough to send his Mig to Tam as a model. This was after it going back to Tam a few times for changes. I got the pipe back and it was not altered. To make it fit, I had to push very hard and it pressed on the bottom of the fuse so much that I thought about cutting out the fuse in the tunnel. Tam assured me this was ok, so I went with it. Fast forward to getting the turbine back. (thanks John) My buddy and I fired it up and set there with a temp gun and monitored every square inch of the back end of the plane. Everywhere was fine except the bottom where it got 200+ degrees on the glass. I was amazed at how cool it was at the bell mouth. The throttle response on the 180RX is awesome!
We shut it down, took it back to the bench to inspect it… not good. This was through three coats of BVM heat shield and the heat blanket. So, I did what I should have done in the first place. Piece of G10 and some glass and its close to being ready to paint. I have a little over 3/8" clearance around the pipe now, makes me feel much better. :-)
We shut it down, took it back to the bench to inspect it… not good. This was through three coats of BVM heat shield and the heat blanket. So, I did what I should have done in the first place. Piece of G10 and some glass and its close to being ready to paint. I have a little over 3/8" clearance around the pipe now, makes me feel much better. :-)
12-20-2013, 05:40 PM
#62
My Feedback: (21)
Doc,
I had an OVT version with a p200 in it . I had to raise the engine about 1/4" to make it work with the Skymaster TV pipe. The pipe barely touched the bottom of the fuse but I had a layer of ceramic felt heat resistant fabric and a coat of BVM heat shield paint between the pipe and the fiberglass. It was fine I had no issues with heat damaging the glass..
I had an OVT version with a p200 in it . I had to raise the engine about 1/4" to make it work with the Skymaster TV pipe. The pipe barely touched the bottom of the fuse but I had a layer of ceramic felt heat resistant fabric and a coat of BVM heat shield paint between the pipe and the fiberglass. It was fine I had no issues with heat damaging the glass..
12-20-2013, 09:43 PM
#64
Bob, My skymaster pipe was the wrong one and it was literally falling apart. The one Tam made for me had one bend in it, the sky master had two… I raised the turbine as well, still too tight. Just another curveball, it will all get sorted out.
Sebastian, I wish I would have done twins!
Sebastian, I wish I would have done twins!
12-21-2013, 08:55 PM
#66
Dr Scoles
See if Skymaster will replace the original pipe with one that's not falling apart. I know Tam makes an excellent pipe but I have never heard of any Skymaster Mig 29 pipe failures, standard or OVT. Skymaster have heaps of testing with there own pipe. It is up to the task and it does fit.
All the best for the maiden.
Levi
See if Skymaster will replace the original pipe with one that's not falling apart. I know Tam makes an excellent pipe but I have never heard of any Skymaster Mig 29 pipe failures, standard or OVT. Skymaster have heaps of testing with there own pipe. It is up to the task and it does fit.
All the best for the maiden.
Levi
12-21-2013, 09:00 PM
#67
They also gave me the wrong bell mouth, it was HUGE. It took a lot of cajoling to get the proper bell mouth, then they sent two…lol. What sucks, is it took a while to realize they sent the wrong pipe, it almost fit… Its all better now, got it back together tonight. I can get my middle finger between the bottom of the pipe and the fuse, should be OK.
The OVT does add a lot of complexity, the linkages and mounting the rear nozzles is entertaining. However, I think high alpha passes, tumbles and flat spins will make it worth the effort.
The OVT does add a lot of complexity, the linkages and mounting the rear nozzles is entertaining. However, I think high alpha passes, tumbles and flat spins will make it worth the effort.
12-26-2013, 10:45 AM
#68
My Feedback: (11)
I havent touched my mig Lately.
The person who had it before me has shaved a lot of the balsa away in the wing underneath the ailerson servo to try to get the servo to fit. I dont like that at all. I plan to fill and reglass.
A better solution is to have a small bubble in the servo cover. It will only have to be very slight. I'm more of a "in the air" guy so I wont be able to see that small of detail in the air. Many jets/planes I have seen with thin wings use this approach. The mig is draggy anyways so what a few mm sticking down from the wing going to do anyways.
My stock pipe also touches the bottom of the fuse. The "Y" straddles the intake hump and touches it on both sides. I just have 2 layers of heat blanket now I am worried about it.
I think what put me off of working on it is not having the turbine right now. I sent if off early in the month to get it upgraded (p180rx).
I'm also short 4 servos since because of the wing issue. Also the vert stabs need surgery to make a standard servo fit. I suppose I could use some thin wing servos but they have a max torque of 75 oz/in. They also buzz like crazy and drive me nuts.
So once I do some more testing I will order servos depending on the results, and then it will go together quicklly. Well of course have to fix the oil leak in the front strut.
These things are tinker toys for sure. I have yet to have a jet with oiled filled struts that dont end up with issues.
The person who had it before me has shaved a lot of the balsa away in the wing underneath the ailerson servo to try to get the servo to fit. I dont like that at all. I plan to fill and reglass.
A better solution is to have a small bubble in the servo cover. It will only have to be very slight. I'm more of a "in the air" guy so I wont be able to see that small of detail in the air. Many jets/planes I have seen with thin wings use this approach. The mig is draggy anyways so what a few mm sticking down from the wing going to do anyways.
My stock pipe also touches the bottom of the fuse. The "Y" straddles the intake hump and touches it on both sides. I just have 2 layers of heat blanket now I am worried about it.
I think what put me off of working on it is not having the turbine right now. I sent if off early in the month to get it upgraded (p180rx).
I'm also short 4 servos since because of the wing issue. Also the vert stabs need surgery to make a standard servo fit. I suppose I could use some thin wing servos but they have a max torque of 75 oz/in. They also buzz like crazy and drive me nuts.
So once I do some more testing I will order servos depending on the results, and then it will go together quicklly. Well of course have to fix the oil leak in the front strut.
These things are tinker toys for sure. I have yet to have a jet with oiled filled struts that dont end up with issues.
12-26-2013, 11:10 AM
#69
I used the smaller servos for the ailerons and rudder. There are a lot of sky master migs flying with servos of that size! I'm using the 9071 sbus servos, 64oz at 6v. The elevators got the 400oz flavor, but one of my friends made a good point, do you think the plywood is going to hold a 400oz load?
To be clear, the double wall on my pipe was collapsed where it burned the bottom of the fuse. I was informed that it would be fine, and it obviously wasn't. I would try it and just monitor the temp very closely. I got a little infrared temp gun a long time ago that works perfect. A buddy told me you can soak the heat blanket with the BVM heat shield and it will stay put. I had some foil right around the back end of the turbine, it all got sucked out almost immediately.
Is it the air or oil in your front strut? Mine leaks out after a few months, this seems acceptable to me.
This kit has been a PIA.
To be clear, the double wall on my pipe was collapsed where it burned the bottom of the fuse. I was informed that it would be fine, and it obviously wasn't. I would try it and just monitor the temp very closely. I got a little infrared temp gun a long time ago that works perfect. A buddy told me you can soak the heat blanket with the BVM heat shield and it will stay put. I had some foil right around the back end of the turbine, it all got sucked out almost immediately.
Is it the air or oil in your front strut? Mine leaks out after a few months, this seems acceptable to me.
This kit has been a PIA.
12-26-2013, 11:54 AM
#70
The is no need for strong servos for alierons the mig fly best with delta mix for the big elevators ,the big comp arf mig using only the delta mix for elevators and the alierons is not in use just little up fix deflection ,I did try to fly my skymaster f-22 with both configuration and the delta mix work the best ,so the mig will have the same mix delta for elevators + regular alierons with 15% less deflection than elevators and only 5.5 kg flat wings servos same servos for ruders ,I have the chance to look on the full scale mig -29 surface setup and the biggest think is the elevators ,all the other surfaces is use for hard air to air combat for speed breaking when the rudders go in or out flaps down and alierons up with computer assist for other maneuvers when in combat situation .
12-28-2013, 01:29 PM
#72
Originally Posted by essyou35
Got my P180rx back today. So I guess there is no more excuses. I am going to try the mini servo option. Thanks for the input.
I managed to squeeze in a full size servo for the aileron, but as some suggested above its probably not necessary. I did have to cut the cover a little though. Also i found the JR 3421 a good fit for the rudder.
Levi
12-28-2013, 09:00 PM
#73
Essyou, you might want to consider glassing the entire rear most hatch. I originally just put a few carbon strips across to make it more rigid. Now that I've ran the turbine a few times, any heat at all will make the thin fiberglass really soft. A few places on that hatch got to only 130 degrees and the glass got flexible. This was with three coats of bvm heat paint. After glassing and painting again, no problems.
12-29-2013, 06:18 AM
#75
You are probably right Sebastian. The flange on the hatch was deformed by the heat just sitting on the ground. Also, the two rear hatches are so flimsy, when in flight, they can get sucked down and distorted. I just want a solid airframe. Maybe its because I've had three BVM jets and two comp arf, didn't experience these things with them.
