RE: Alfa Model Mig 15  
View related threads: (in this forum | in all forums)

Tower Hobbies
Enter up to 4 keywords or Tower stock numbers
Logged in as Guest



Users viewing this topic: none
  Printable Version
       


EASYTIGER'S Mirage IIIC VERY HIGH PERFORMANCE ONLY $129!
Seller:  EASYTIGER
Details:   $129.00   |  11/10/2008   |  Classified Ad
We will rotate YOUR AD in this spot if you select "Forum Featured" when placing or editing your ad!

All Forums >> Electric Aircraft Universe >> Electric RC Jets >> RE: Alfa Model Mig 15
Page: <<   < prev  3 4 [5] 6 7 8 9 10 11 12   next >   >>  

Login
Message << Older Topic   Newer Topic >>
RE: Alfa Model Mig 15 - 11/23/2004 5:32:31 PM   
the Swamp Fox



Posts: 69
Joined: 12/12/2003
From: Wadmalaw Island, SC, USA
Status: offline 		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 !

(in reply to Woody 51)
       Post #: 101

RE: Alfa Model Mig 15 - 11/26/2004 10:51:44 PM   
Woody 51



Posts: 1159
Joined: 6/21/2003
From: GeelongVictoria, AUSTRALIA
Status: offline 		Swampy.
Are you down Charleston way?

_____________________________

A crash keeps one's opinion of one's flying ability, in perspective.

(in reply to the Swamp Fox)
       Post #: 102

RE: Alfa Model Mig 15 - 11/28/2004 11:22:12 PM   
the Swamp Fox



Posts: 69
Joined: 12/12/2003
From: Wadmalaw Island, SC, USA
Status: offline 		That's affirmative Woody,

'bout 15 mins south of Charleston


seen the F-104 Starfighter vids ?




take care

(in reply to Woody 51)
       Post #: 103

RE: Alfa Model Mig 15 - 11/29/2004 4:08:05 PM   
blue action



Posts: 35
Joined: 11/18/2004
From: Mountain View, CA, USA
Status: offline 		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!!

(in reply to the Swamp Fox)
       Post #: 104

RE: Alfa Model Mig 15 - 11/30/2004 2:44:30 AM   
the Swamp Fox



Posts: 69
Joined: 12/12/2003
From: Wadmalaw Island, SC, USA
Status: offline 		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 .

(in reply to blue action)
       Post #: 105

RE: Alfa Model Mig 15 - 11/30/2004 3:33:36 AM   
blue action



Posts: 35
Joined: 11/18/2004
From: Mountain View, CA, USA
Status: offline 		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!

(in reply to the Swamp Fox)
       Post #: 106

RE: Alfa Model Mig 15 - 11/30/2004 12:03:25 PM   
Woody 51



Posts: 1159
Joined: 6/21/2003
From: GeelongVictoria, AUSTRALIA
Status: offline 		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.

< Message edited by Woody 51 -- 11/30/2004 12:06:40 PM >

_____________________________

A crash keeps one's opinion of one's flying ability, in perspective.

(in reply to blue action)
       Post #: 107

RE: Alfa Model Mig 15 - 12/1/2004 4:31:05 PM   
blue action



Posts: 35
Joined: 11/18/2004
From: Mountain View, CA, USA
Status: offline 		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 . 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.

(in reply to Woody 51)
       Post #: 108

RE: Alfa Model Mig 15 - 12/1/2004 10:40:30 PM   
Loopman



Posts: 411
Joined: 2/14/2002
From: Duluth, GA, USA
Status: offline 		Is there an alternative motor to the MP Jet 25/25-26 as Hobby Lobby is out until the end of January!

Thanks

Loopman

(in reply to nitroshark)
       Post #: 109

RE: Alfa Model Mig 15 - 12/2/2004 12:40:40 AM   
wekenav8r



Posts: 108
Joined: 12/26/2001
From: Marysville, WA, USA
Status: offline 		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.


_____________________________

Tim

(in reply to Loopman)
       Post #: 110

RE: Alfa Model Mig 15 - 12/2/2004 11:15:23 AM   
Woody 51



Posts: 1159
Joined: 6/21/2003
From: GeelongVictoria, AUSTRALIA
Status: offline 		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.

_____________________________

A crash keeps one's opinion of one's flying ability, in perspective.

(in reply to Loopman)
       Post #: 111

RE: Alfa Model Mig 15 - 12/2/2004 4:19:42 PM   
Loopman



Posts: 411
Joined: 2/14/2002
From: Duluth, GA, USA
Status: offline 		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

(in reply to Woody 51)
       Post #: 112

RE: Alfa Model Mig 15 - 12/2/2004 9:11:57 PM   
Woody 51



Posts: 1159
Joined: 6/21/2003
From: GeelongVictoria, AUSTRALIA
Status: offline 		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.

_____________________________

A crash keeps one's opinion of one's flying ability, in perspective.

(in reply to Loopman)
       Post #: 113

RE: Alfa Model Mig 15 - 12/2/2004 11:28:08 PM   
Loopman



Posts: 411
Joined: 2/14/2002
From: Duluth, GA, USA
Status: offline 		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