HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jul 20, 2011, 07:24 AM
Team30 Micro EDF
NitroCharged's Avatar
Adelaide, Australia
Joined Apr 2004
11,254 Posts
I don't have pitch issues - sounds like you guys need to better balance the Mig.
NitroCharged is offline Find More Posts by NitroCharged
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 20, 2011, 07:40 AM
Life begins at transition
Australia, VIC, Sale
Joined May 2007
3,593 Posts
I cut a V out of the bottom seam. It would appear to move the exhaust upwards, which would really excaserbate the problem. It's quite noticable, but I've gotten used to it. 1/2 throttle is trimmed, idle needs a lot of back schtick, max needs a lot of forward. Not ideal, but it flies!

NC - Your thrust tube I think bypasses the problem in the foam exhaust. My gut feeling (and I didn't check when I had the fuse is pieces!) is the bottom part of the fuselage tapers up at the exhaust, whereas the top stays pretty much straight. That'd act a bit like a thrust vectoring nozzle, permanantly pushing the tail down.
Your tube would be a straight line all the way back - no angles, no problems.

Like always, jets need tubes. Truth be told, I completely forgot when I was re-assembling! Otherwise, I'd spend the 5 min, get better thrust, and no pitching issues
Odysis is offline Find More Posts by Odysis
Reply With Quote
Old Jul 20, 2011, 09:28 AM
Registered User
mihah's Avatar
Menges, Slovenia
Joined Dec 2002
302 Posts
I have thrust tube installed on the bottom of the exit. Just transparent mylar foil which goes from 110 mm to 98 mm circumference and ends at the exit. I have just taped the tube to the edf and it sits quite tight.

I made THR -> ELEV mix about 11 % in total (5-6 % in each direction from the center). If I fly smootlhly there is hardly any pitch change noticable, even with throttle off.

I really like this little plane a lot! :-)
mihah is offline Find More Posts by mihah
Last edited by mihah; Jul 20, 2011 at 09:45 AM.
Reply With Quote
Old Jul 20, 2011, 09:34 AM
Canadian Bacon
flypaper 2's Avatar
Kingston, Canada
Joined Jun 2004
13,187 Posts
I would agree with Nitro that it's a balance problem. Sounds nose heavy if you need a lot of up elevator to keep the nose up with power off. With a fast flat glide, the elevator should be level or neutral.

Gord.
flypaper 2 is offline Find More Posts by flypaper 2
Reply With Quote
Old Jul 20, 2011, 10:13 AM
Gravity is a harsh mistress.
Tim Wolff's Avatar
United States, MI, Temperance
Joined Sep 2002
6,608 Posts
Quote:
Originally Posted by flypaper 2 View Post
I would agree with Nitro that it's a balance problem. Sounds nose heavy if you need a lot of up elevator to keep the nose up with power off. With a fast flat glide, the elevator should be level or neutral.

Gord.
Thanks for the tips on the CG. I have an F/A-18 that pitches up like crazy with throttle. I'll move the CG back and see how it does.
Tim Wolff is online now Find More Posts by Tim Wolff
RCG Plus Member
Reply With Quote
Old Jul 20, 2011, 10:56 AM
Registered User
Joined Sep 2005
376 Posts
...I didnt read far enough.. (edit)
JackDaniels is offline Find More Posts by JackDaniels
Reply With Quote
Old Jul 20, 2011, 11:41 AM
Registered User
bluemeane's Avatar
Joined Apr 2007
1,126 Posts
Quote:
Originally Posted by SonicRaT View Post
Read the thread from start to finish, and had to jump on board! Using the Buddy Code's it all came out surprisingly cheap! After going through the thread here's the various odds and ends I settled on:

F86 ARF (just can't get into the mig lines...)
Orange 4ch receiver
Turnigy Plush 10A ESC
Turnigy NT 460mAh 3S
HK 2.5g Micro servo's
.5 Carbon rod

Should make for a fun addition to my rather tiny hangar, and certainly will keep me busy while I search for various parts to restore my Sapac F-22 to flight condition!
What is a "buddy code"? And how can I get one(some)?? lol


Edit: So i found out what they are... Do you have a buddy code for your order?? I'd love one.
bluemeane is online now Find More Posts by bluemeane
Last edited by bluemeane; Jul 20, 2011 at 11:47 AM.
Reply With Quote
Old Jul 20, 2011, 07:00 PM
Registered User
United States, CA, San Diego
Joined May 2004
473 Posts
I just got the red mig at my office today. I have some 2c nano's on the way. What is the best way to get a DSM receiver in there? Solder on new plugs? What RX have people been using? if soldering on new plugs, is there a handy source for pigtails?

Thanks,
scott.
GuppyG is offline Find More Posts by GuppyG
Reply With Quote
Old Jul 20, 2011, 07:43 PM
Life begins at transition
Australia, VIC, Sale
Joined May 2007
3,593 Posts
FP2: Yes, the CoG is too far forward, as I've already alluded to (excessive stability), but if you move it too much further aft, the 'death spiral' becomes even more prevelant.

Also, the pitching happens on application of throttle, not just with changes in speed.

As Nitro said, if you stick a thrust tube in it, the problem goes away. He's using the same CoG (within 1mm give or take), but doesn't have the thrust vectoring.

It won't take long to fix, but does involve slicing the fuse in half again. I think I'll wait 'till I'm replacing the power system and do it then, as it's flyable and enjoyable as is, just not perfect.

Guppy - I left the pins on my Rx, but took the plastic keepers off the micro servo leads. The metal sockets will still fit onto the standard sized pins. I was thinking of removing the pins and soldering everything, but when I found they fit with very minimal modification, I couldn't help but be lazy!
Odysis is offline Find More Posts by Odysis
Reply With Quote
Old Jul 20, 2011, 07:59 PM
ancora imparo
jj604's Avatar
Melbourne, Australia
Joined Jul 2005
6,881 Posts
Just a quick question. Do you have to slice the fus to fit a tube? My Mig has a 36.8mm exit hole which is identical to the OD of the fan housing. If I recall Nitro said he was using a 34mm exit tube. Why can't you just make a 36.8mm OD at the front, 34mm ID at the back thrust tube and stuff it up the through the exit hole and glue it on? It would just fit through without any mods to the plane.
Quote:
Originally Posted by Odysis View Post
As Nitro said, if you stick a thrust tube in it, the problem goes away. He's using the same CoG (within 1mm give or take), but doesn't have the thrust vectoring.

It won't take long to fix, but does involve slicing the fuse in half again.
jj604 is offline Find More Posts by jj604
Reply With Quote
Old Jul 20, 2011, 08:15 PM
Not enough hours in the day
Slaanesh's Avatar
Melbourne
Joined Feb 2009
2,429 Posts
Quote:
Originally Posted by jj604 View Post
Just a quick question. Do you have to slice the fus to fit a tube? My Mig has a 36.8mm exit hole which is identical to the OD of the fan housing. If I recall Nitro said he was using a 34mm exit tube. Why can't you just make a 36.8mm OD at the front, 34mm ID at the back thrust tube and stuff it up the through the exit hole and glue it on? It would just fit through without any mods to the plane.
I think the only advantage of the slice is that it's easier to fit at the cost of making a slice.

I would go with the method you've outlined despite the extra fiddling about.

I did the same thing to another EDF I built - made the fuse first then fit the thrust tube.
My trial fit became the real fit as it was so awkward and fiddly to do! From then on I vowed I would always make and fit the tube before completing the fuselage, if possible.

Sometimes I wish I had a third hand - would be extremely handy for modelling!

By the way John, where are you flying your little Mig-15? Local parks? Or SEMAC?
Slaanesh is offline Find More Posts by Slaanesh
Reply With Quote
Old Jul 20, 2011, 08:27 PM
Life begins at transition
Australia, VIC, Sale
Joined May 2007
3,593 Posts
NC made his tube, and didn't mod the airframe.
For me, it was a quick, 2 min job to shrink the tail down a bit, whereas splitting the fuse takes a while. I've only tried to fit a thrust tube after fan installation once. Never again! So fiddly, as Slaanesh said, not worth it in my book.

34mm still seems excessive for a 35mm fan. But then again, NC may not be using the stock fan...
Odysis is offline Find More Posts by Odysis
Reply With Quote
Old Jul 20, 2011, 08:31 PM
ancora imparo
jj604's Avatar
Melbourne, Australia
Joined Jul 2005
6,881 Posts
I just gave it a go at the local park. Nearly got eaten by a big white dog when it landed! Since it remains undamaged , I put it back in the hanger for now - other projects to do.
Quote:
Originally Posted by Slaanesh View Post
By the way John, where are you flying your little Mig-15? Local parks? Or SEMAC?
jj604 is offline Find More Posts by jj604
Reply With Quote
Old Jul 20, 2011, 08:47 PM
Life begins at transition
Australia, VIC, Sale
Joined May 2007
3,593 Posts
Just got back from another couple of flights in my 'front yard'

FP - I checked it's glide. I cut the throttle up high, nosed over to about 45* nose down. As is picks up speed, it gently pulls up, but not more than maybe 10-15* in the height I gave it. When you punch the throttle, it goes to about 30* nose up!

The more I think about it, the more I should just bite the bullet and fix it
Odysis is offline Find More Posts by Odysis
Reply With Quote
Old Jul 20, 2011, 09:57 PM
I don't want to land yet!
Joined Jan 2010
1,500 Posts
Ody, I made my thrust tube after gluing the fuse together.. Just tape the exit end and shove it in, then you can tape it to the fan, not ideal I know but it works fine. You can then put more tape inside from the back with a stick, doesn't need much to hold it...
Strike3 is offline Find More Posts by Strike3
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Mini Mig-15 EDF from Hobby King Dreamcatcher Foamy EDFs 6 Jan 16, 2012 10:58 AM
New Product JPower/Banana Hobby 40mm Foam Mig-15 and F-86 ducted fan Mikemynameis Micro EDF Jets and Power Systems 557 Aug 18, 2011 06:01 PM
Build Log Hobby King Micro A-6 & F-86 Jets tallflyer Foamy EDFs 4 Jun 04, 2011 03:05 PM
New Product J-Power 30mm EDF Jets (F-86 & Mig-15) xplaneguy Foamy EDFs 1 Jan 16, 2011 06:59 AM
Park/indoor EDF F-86 and MiG-15 production news! Thomas B Parkflyers 8 Feb 06, 2002 07:30 PM