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Alfa Model Mig 15

Old 11-23-2004, 12:32 PM
  #101  
the Swamp Fox
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Default RE: Alfa Model Mig 15

good luck with the Panther...didn't look too slow to me !

loved the way it rolled.

Aiken huh?

that's only a couple hours away , a freind that lives down here on the coast is from there.

be sure to post impressions and pics of the panther once ya get it !!!

best of luck !
Old 11-26-2004, 05:51 PM
  #102  
Woody 51
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Default RE: Alfa Model Mig 15

Swampy.
Are you down Charleston way?
Old 11-28-2004, 06:22 PM
  #103  
the Swamp Fox
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Default RE: Alfa Model Mig 15

That's affirmative Woody,

'bout 15 mins south of Charleston


seen the F-104 Starfighter vids ?




take care
Old 11-29-2004, 11:08 AM
  #104  
blue action
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Default RE: Alfa Model Mig 15

Hi there, sorry for interrupting, I hope this is the right place to post a question about the EDF assembly for the Alfa Mig15.

I have just finished the assembly of the EDF power unit with the MJ 25-26 Mk2 motor and hooked it up. Nice thrust, I can blow a door open from 5ft away

Regarding the vibrations, how can you tell if the vibrations are 'good' or 'too much'? The instructions tell you to be very prudent with balancing the aluminium plug, adjusting the fan etc. to remove vibrations to improve performance and life time of engine bearings. Well I can tell you the thing is screaming (seems to have the same aggressive sound as on Andy Steere's videos) and after a couple of minutes holding the fan in my hands at 50-70% thrust my hand feels kinda numb and shaky. I guess there are some vibrations, but hey the thing is spinning at 30-40000 rpm so what do you expect.

So here's my question. Would you guys recommend to disassemble the whole thing and do more balancing to try to eliminate the vibes? I can't get the fan off easily any more as the screw holding it won't come off (it turns the aluminium plug and motor shaft and I can't hold it).

Another question regarding wing gluing. My packet came without that 'UHU' but only 5min epoxy. Will it be OK to glue everything (also wings) with the epoxy? (sanding and poking surface areas)?

Thanks!!
Old 11-29-2004, 09:44 PM
  #105  
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Default RE: Alfa Model Mig 15

Hi Blue,

If you read alfa power instruction section . It will tell you there will be an rpm range where vibration will occur . Advance throttle rapidly through those ranges. Mine vibrates @ a little more than 1/2 throttle so I don't fly there. If it vibrates throughout the entire throttle range, someting is out of balance.
Don't use 5 min epoxy...go for the slow cure or probond....it's stonger
sand the root, poke MANY holes through the fuse...allow the epoxy to seep inside the fuse...I then laid up .75oz glass to soak it up and add a little strength..so far so good

Apologies, we were drifting a bit off topic as noone was really posting on the mig

MiG 15 sortie#72 complete

best of luck .
Old 11-29-2004, 10:33 PM
  #106  
blue action
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Default RE: Alfa Model Mig 15

Swamp, the vibrations don't change with throttle setting, pretty consistent across the whole RPM range (except very low power). But I played around a little more with it, and to my surprise when I take off the 'spinner' snap-on cap the vibrations are almost completely gone. I guess I'll start experimenting with putting a little tape inside the spinner like somebody else suggested on 'the other forum'. I'm just glad I don't have to take off the whole fan (that would be a mess as the screw won't open).

Thanks for the tip with the slow-cure. Will use my 30 min epoxy leftovers from the last 'hard landing' with my hotliner. I'll also put it some clothes inside the fuse in the area where the wings attach.

Will keep you posted!
Old 11-30-2004, 07:03 AM
  #107  
Woody 51
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Default RE: Alfa Model Mig 15

Blue, a little Great Planes Milled Fiberglass mixed into your epoxy is also a good alternative.

Re vibrations. All turbines have what is knows a "Critical Speed" range. Swampy is right in that you must get them through it as quickly as possible, though it sounds like the end cap on yours is out of wack.

Swampy, I used to work for a Charleston Company. Love the city. Hope to get back there for a "look see" in about 12 months or so.
Old 12-01-2004, 11:31 AM
  #108  
blue action
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Default RE: Alfa Model Mig 15

Found a solution to the vibrations induced by the spinner: put it flat on the table and noticed it tilted quite a bit to one side. Put a couple of medium sized drops epoxy inside the spinner to the lighter side and let it dry. Repeated process until it was balanced and stood upright on the table (on its tip). NOW we're talking! Runs very smooth now, and I have not found any 'critical RPM range' so far. Could not resist to use the fan to fire up my bbq last night- those pork chops were done in no-time . (After all these EDF tests my 1-year old son starts imitating that noise all the time- mmmmmmmmhh)

Also removed the paint from the fuse where the wings attach with a sharp knife. Have blank styro now where the glue will go (punctured too). Unfortunately I cut into the surface a little to deep at one point so there's only ~2mm material left in an ~.5 inch long area somewhere in the forward third of the wing attach area [&o]. But I am planning to put some epoxy soaked glass cloth inside the fuse in that area, so it should not matter. I hope.

Need to find a quiet hour one of these nights to glue the wings on. Will keep you posted.
Old 12-01-2004, 05:40 PM
  #109  
Loopman
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Default RE: Alfa Model Mig 15

Is there an alternative motor to the MP Jet 25/25-26 as Hobby Lobby is out until the end of January!

Thanks

Loopman
Old 12-01-2004, 07:40 PM
  #110  
wekenav8r
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Default RE: Alfa Model Mig 15

If you don't mind spending an extra $10, check and see if they have the motor with the gearbox in stock. I did this a couple months ago when they were out of stock on the MPJ motor. Then just pry off the pinion gear and take off the gearbox and you're ready to drop it in the fan. It's the same motor, just comes with a reduction gearbox installed.
Old 12-02-2004, 06:15 AM
  #111  
Woody 51
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Default RE: Alfa Model Mig 15

Try AIRCRAFT at

http://www.aircraft-world.com/shopexd.asp?id=2032

They've got 'em at $50.95 plus postage. Even thought they are in Japan, postage to the US is extremely cheap and delivery takes about 4 days from payment.

They take PAYPAL.

I get a lot of my elect R/C stuff from them. Service is great and they are very reliable.
Old 12-02-2004, 11:19 AM
  #112  
Loopman
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Default RE: Alfa Model Mig 15

Hey Fellas,
Thanks for the advice on a substitute motor! I ended up ordering a HiMax 2015-4100 and am eagerly looking forward to getting this "communist comet" in the air! I am also going to try using an HS-81 servo for the ailerons, it's a little heftier on torque than the HS 55's.

Happy Flying!

Loopman
Old 12-02-2004, 04:11 PM
  #113  
Woody 51
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Default RE: Alfa Model Mig 15

Hi Loopman,

The Himax will run quite hot inside the ALFA fan unit shroud.

Suggest you look at the mods that ANDY STEER has done to his (and posted on the internet,) to to help alleviate the heat problem.

See:http://astro.umsystem.edu/andy/rc/mig15/

and go right through the site.

N.B. The recommended MPJET motor also gets hot, so don't worry that you've may be purhased a problem.

Let us know how your bird flies. It's always good to get feedback, we're all interested.

Good Luck.
Old 12-02-2004, 06:28 PM
  #114  
Loopman
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Default RE: Alfa Model Mig 15

Yep! I have gone through Andy's site and even saved it as one of my favorite places. The shroud without a doubt needs some cooling flow through! I will keep everyone posted on how it all comes out.

Happy Flying!

Loopman
Old 12-02-2004, 10:32 PM
  #115  
Pilot44
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Default RE: Alfa Model Mig 15

Swamp man,



Thought I'd find you here....

Shot off a note to our friends at Alfa. Atonin Alfrey, says there are things in the oven. but not giving it up yet..... Hopefully another EDF...

Jim G
Old 12-03-2004, 12:39 PM
  #116  
the Swamp Fox
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Default RE: Alfa Model Mig 15

JIM!

What's happenin' ole boy?!?!

we'll see what we get

RE : motors

Been flying the MiG since June. mpj mkII 25/25 /tanic 1550
Maiden was on a 90f day with NO wind.
Flew it all summer in the deep south ,and she's still going strong.
(flights limited to 5-7 min )

point: I built it per spec. With the rear cone in place.
Although it's prolly best to leave tail cone etc off for better cooling, but in 75 flights...no worries

Just tested out a vasa 55/ park 400 combo thats putting out a good deal more power(around 190watts) than my stock alfa setup (130watts) ...may fit that in and see what we happens in the air.

Loopman, greetings from your sister city

best of luck all
Old 12-03-2004, 03:50 PM
  #117  
Woody 51
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Default RE: Alfa Model Mig 15

Hi Swampy,

Just had a look at STUMAX's new F104 video. Looks great.

Stu says he's running a Hacker B4019L/Wemotec Minifan480 combo on 9S1P 2600mAh lipos in it.

He also said that combo draws 28A hot off charger, settling to about 24A.

He is just finishing off my Panther, should be ready to post by Tuesday/Wednesday next. I'll let you know how the kit is.

As regards upcoming ALFA'S, Anton told Zdenek (our local Alfa guy) that the numbers are being currently crunched for an ME 262 twin mini EDF, as a future release.
Old 12-03-2004, 05:40 PM
  #118  
the Swamp Fox
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Default RE: Alfa Model Mig 15

Anton told Zdenek (our local Alfa guy) that the numbers are being currently crunched for an ME 262 twin mini EDF, as a future release.


MY FAVORITE!!!!!

If you're kidding me, I WILL track you down and deal you a serious pummeling


-teasin' of course ...
Old 12-03-2004, 05:55 PM
  #119  
Loopman
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Default RE: Alfa Model Mig 15

Hey Swamp Fox,
I didn't know Wadmalaw had any realtives! ( He He ). I grew up in Charleston and spent alot of time on the islands hunting. I would guess that all the areas where I use to squirrel hunt are full of houses and condos now. Just got my MIG and it looks very, very nice. I am going with a HiMax 2015-4100 using Thunder Power 1320 li-po's. This will be my first venture into EDF flight but I've been flying gas for a number of years, also flying a Shockflyer as well, that's a hoot!

Happy Flying!

LOOPMAN
Old 12-04-2004, 01:23 PM
  #120  
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Default RE: Alfa Model Mig 15

well it looks like you guys talk me into getting one of this little jewels ,just finish assembling the fan unit and motor installation , fired it up excellent thrust , hardly any vibration if any ,i must have got lucky , now my only question where do i get this UHU por foam glue ? thanks Ed
Old 12-04-2004, 02:14 PM
  #121  
Loopman
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Default RE: Alfa Model Mig 15

Hey Fellas,
FYI, quite a few arts & crafts stores carry the UHU glues. You can even find CA, X-Acto and balsa and bass wood there as well.
Happy Flying!

Loopman
Old 12-04-2004, 08:31 PM
  #122  
the Swamp Fox
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Default RE: Alfa Model Mig 15

Hey all ,

My ALFA fan was starting to sound a little rough and the rotor blades have a few chips and performance is down

picked up a VASA55 fan and a e-flite park 400 4200kv + a FSK F-16 at the local shop . Didn't feel like waiting on anything ...wanted to continue MiG patrols as scheduled. Then migrate the vasa combo into the FSK .
wedged the new fan /motor in the MiG ..
ran up on wattmeter on a TP2100 genII 3s --- 19a 194 watts settling to about 17a 184w
this compared to 12a 130w on the mpjet mk II /Alfa fan .

thrust seemed very nice !

High hopes

Test flight was on a Tanic 1550
.65ozl weight gain in the motor caused proper CG to be a little tricky to achieve .
Was a little tail heavy ,but I have a few hours on this plane so I figured no worries .

I go to the field , getting out of the car I turn to grab my radio and mangage to "Karate chop "the port elevator and stab in half .DOH!

%#**!!! Clean break so I run home 5 min epoxy repair never tell it happened . *Whew*

back to the field ... ignored the omens

First launch a near disaster ! This from the easiest handlauncher I own . Climbed up, she wanted to stall.l Held on the power until I could get a wing over then cut power and pulled out easy and slid in ...*whew *

second : adjusted CG still had pitch up, but got her settled by holding down stick...
third ...just 'cause...I was dissappointed ,thinking my thrustline was off .

performance wasn't what I was after ..

today, switched to the heavier TP2100 AHHHH...ok Here We go~!

1. cg was on
2. Same numbers as wattmeter with the Tanic. Was balance NOT thrustline...whew again ... + I noticed a little postive reflex in ailerons which I introduced inadvertantly I 'spose when I refit her. AHAH!!! That's why preflights are so critical ...I tend to rush those .

grooved nicely ...decent gain in top end around 5-7k maybe

nicer climbouts ...Extra weight gave me more speed in dives which I could use in transition for tighter rolls and big invert climbouts with no stalls at the top as before (sometimes)

downside ...little longer approaches and more load on those wings

The Vasa runs quiet and smooth ..I forgot to limit flight to 5-7
checked timer .. 12 minutes landed at dusk...everything just a tad warm .


Good luck all, and get those Migs up..Sabres spotted 12 0'clock high!

Loopman,
Born raised in Charleston/Islands myself .
But there aint no condos out here
only commercial is farming and 1 tiny store.
no gas station
no police
loads of Spottail off the dock
ahhh...yesss.....
Old 12-06-2004, 10:33 PM
  #123  
mavdriver
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Default RE: Alfa Model Mig 15

swamp fox you didn`t say if you like this motor and fan set up better verses the old set up you had . Ed ps my little mig is almost done [8D]
Old 12-06-2004, 10:38 PM
  #124  
mavdriver
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Default RE: Alfa Model Mig 15

hey lopman thanks for the info on the uhu i did find it at michaels art and craft store . Ed
Old 12-06-2004, 11:31 PM
  #125  
the Swamp Fox
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Default RE: Alfa Model Mig 15

Sorry Mav,

I like the setup...but it was an emergency fix to keep the MiG flying + power for another small edf.

The vasa is a more aggressive fan so it seems so really high KV motors may overdraw your packs.

I'm @ 18-19a now.

I also had to do a little grinding ,sanding, twisting and wedging to get installed AND removable.

I'm quite pleased with it ., but will go back to the "drop-in" ALFA , and try some lighter higher KV motors when I can get the fan.

We shot some vid of this evenings patrol with the vasa combo .....

www.southcarolinacoastalmagazine.com/vasamig.wmv

good luck all!

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