Viper1GJ

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Updated flight report:

Flew Mig-29 again today. Much improvement.

The CG was moved back from 155 to160mm and is now 20mm aft factory recommendation. It made a big difference. Take off rotation was much smoother and easy, no jump take offs. Airborne CG check with pull to 45 degree upline and roll inverted, showed a very slight pitch to canopy, much better than before. Landing is very easy with a long steady flare to touch down on mains with nose in the air.

The thrust line adjustments were good. Now there is no pitch change when adding thrust from low speed. I think the airframe is really dialed in now and it is fun to fly with no bad habits I have seen. This is my favorite FW turbine conversion so far.

I did have problems keeping the turbine going but that is not an airframe problem. Seems like it wants to quit when pulling throttle back quickly. Auto restart works great and I used it several times to day. Suggestions welcome.

Gary











Got a little gatoring on the AB nozzle. Probably from all the auto starts I had today. I will put some HVAC aluminum tape on it and paint it.

yeahbaby

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Nice work amigo.

ravill

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Try pulling back on the throttle slower?

If I remember correctly BVM had some problems with the ultra bandit when the throttle was pulled back too fast. I believe the fix was bigger fuel tank hardware and an extra vent in the header tank.

I love your threads Gary!!!

Bob_B

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Nice work Gary!

alasdair

Great work Gary, both the model and the thread describing it.
Made me look for European agents. Tempted.
Question though on conversion.
What did you use for removing chunks of foam. I saw the device in the photos, but did you make it or buy it or is it a conversion ?
Details please.

raydar

Cheers for the updates on your conversions all the details are very useful.

Try increase deceleration delay by a few seconds to stop the flameouts.

Viper1GJ

My Feedback: (20)

Thanks for the compliments guys.


alasdair, the Mig-29 flies great. You will love it.

I think this is the gadget you asked about. It is a lightweight hot wire foam cutter. I got it several years ago from one of my wife's hobby craft stores.
Its a simple wall wart transformer to a handle with a push button switch. I wrap a piece of Velcro around the button to keep it on when cutting. I made the wire cutter from a piece music wire. The small cutters that came with it were not very useful.

I suggested to Keith to make one from a solder gun and shape a piece of music wire for the cutter. Just use the gun trigger to control the heat.

Viper1GJ

My Feedback: (20)

HVAC tape applied to nozzles.


HVAC tape applied and red label ink wiped off with acetone


Tape painted to match nozzles

I attached all 6 air to air missiles to the wings and rechecked the CG. The missiles move the CG aft 2mm which is not significant. Hope to test fly with stores on next weekend.

alasdair

I found a supplier in Europe. Ended up buying the L39 though.
I have solder gun, so I'll look into making a wire cutter conversion somehow.
I also saw a hot wand advertised so ordered one of those too. Thanks again.

Viper1GJ

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Keith and I flew our Mig-29 turbine conversions several times this weekend. The jet is great and my favorite of the conversions I have done. Getting 8.5 min flight times with all the wing stores on and landing with 2-3 min reserve fuel. The sweet spot seems to be around 65-85 mph. Final turn and approach is about 45mph and touch down at 35mph. Slow flight and high AOA is awesome. The jet will park in high AOA and is very stable. It can be held at about 70-80 degree pitch with thrust and will even start to tail slide if thrust is reduced. I did see the deep stall a few times and entry into a flat deep stall spin a couple of times. Recovery was prompt with lots of thrust, down elevator, and anti spin rudder. Not sure where the CG is now since I did several adjustments. It's probably around 160mm now. I started the weekend at 165 but it was a little too close to the edge for me as the nose wanted to hold a higher than desired pitch on final. Its really fun and easy to fly and I'm impressed with how tough the gear and airframe is. I has some turbine shutdown problems and did several dead stick landings before I got it sorted out. Two were hard high AOA tail first with nose slam down that stuffed the nose in the dirt. Each time the there was no damage except for a crumpled nose cone. New one on order. Over all a great fun jet to fly with some simple mods.
Gary

yeahbaby

My Feedback: (21)

Great update amigo and congrats. So 160mm CG is comfy. 60-85 mph on downwind is your target speed for pattern work or just what you’ve found to be good all around speed w/o ripping apart the airframe?

ddfwaj

That's awesome! Looks really good with the missles on her. What ended up being the issue with the turbine?

Viper1GJ

My Feedback: (20)

Yep, 160mm is a good place. I started at 155mm, then 165mm, but went back to 160mm. It flew fine at 165mm but it found it held the nose up on final more than I wanted and tended to float prior touch down with the risk of a drop in landing so I went back to 160mm. Just felt more normal on final.

My speed sensor is the Digitech SB-IAS sensor connected to a Digitech CTU. I'm using a Lua program called "SpeedAnnouncer" in the Jeti radio written by my friend Dave that calls out my speed when I turn it on. My average speed flying around is mostly between 60-85. Not super fast but plenty good for anything you want to do. It gets faster in some dives. I had my speed warning set at 100 but never tripped it. I don't know how fast it will go but I don't need to either. I just want to avoid the foam explosion going too fast. I usually hear about 50mph on downwind with gear down and half flaps and about 45 in final turn with full flaps. Touchdown on mains usually occurs at 35mph if I hold it off.

It flies fine with full flaps at 50-55mph. I did that when trimming for flap flight modes. I'm not worried about running out of servo power with flaps down at those speeds because Keith and I put 140oz torque servos on the stabs. I just laughed at the puny micro servo that comes stock. But I'm not doing any 100mph test runs with full flaps either.

Viper1GJ

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I don't know. The turbine would just quit and then restart. Most time I would just taxi back. I duplicated it 5 times on the table. Could not identify any cause from PW and other data. No air in fuel. I finally robbed the turbine out of my F-4 and stuck it in. No changes to anything else and it flew fine. So I think it is either a mechanical issue inside the turbine or electronic under the cowl. I will have to talk to Dirk and maybe just send it in. I did learn that the ECU settings are stored in the turbine as everything transferred by just plugging in the new motor with out changing anything else.

dwr302

My Feedback: (2)

Another nice conversion Gary! I actually bought the Mig a couple months ago thinking.....I bet Gary will convert this thing....sure enough....here you are! Got to figure out a fuel tank alternative cuz I got no 3D printer or access to one, anyone out there figured out an alternative tank? I have flown the Mig with EDF. Very nice flyer. Did the elevator mods before the first flight. This thing just begs for a turbine.

Aussie1

This is my Freewing SU30 and is a similar install. The tank is a one litre juice bottle with felt clunk, no header, and no flame-outs with the X45. Looking at this install, you could make a semi scale cover over the tank and engine and do this quite easily. The cover over the engine is just some thin aluminum


sheet and the engine air comes fro the intake ducts.

Viper1GJ

My Feedback: (20)

Aussie1 had my idea. Just mount an external fuel tank between the engine tunnels and make a flat cover of G10 or fiberglass over the entire bottom to FOD protect the tank and turbine. Paint it grey and nobody will ever see it in the air. Keith did something like this on one of his foamies and it worked great.

I'd get something like this and feed the the header tank if you wanted more than 1000ml.

https://smile.amazon.com/ZYHOBBY-100...ustomerReviews

dwr302

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Thanks guys! Bottle shopping tomorrow.

Viper1GJ

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Awesome, post pics of your progress!

Viper1GJ

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I installed some afterburner lights from RC Geek. They are programmable and I have to on set point at 85% throttle stick.


Lights are designed to attach to the back of the EDF but I made a simple lite ply mount.


Wires routed to front and operate from a Y connnector to throttle channel.


A 2S LiPo battery supplies power. The battery replaces the weights I had in the nose cone.




I also added another washer under the rear turbine mounts. Now the thrust angel has a little more than 6 degrees down thrust. Have not tested it yet but It seemed to be pitching up a little at high AOA and very low speed. We will see.


Ready for next trip out.

sysiek

My Feedback: (176)

Just one question, do you think that two smaller tanks could go to the air turbine tunnels instead in the center between, my skymaster mig has fuel tanks there.

Viper1GJ

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Yes I think it would work just fine. I know some others have already done it that way. Its a great flying jet. You will like it.
Gary

MarkF

The slope flyers found that covering up the intakes made for a faster jet. So anything that can go there instead of on the outside would be a good idea. If there empty I would block them off at the leading edge.

sidgates

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Would Keith post Print temperatures and number of layer?

sysiek

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Ok , so I just got one and will try it first with the edf power and after I will convert it to turbine for next summer but probably will do the fuel tanks in the air tunnels but this is just a plan