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Old Apr 25, 2012, 11:30 PM
Registered User
Cottonwood Arizona
Joined Aug 2003
581 Posts
Hi guys, I had some requests come in for some more T-28 shirts, thought I would see if any of the Micro T-28 drivers wanted to get in on it too.

I have the Navy in traditional White/Red and Yellow as well as Air Force Gray/Blue
I also put your pilot name or call sign on the chest area - just tell me what you want for the name.

Shirts are $20 each + $5 shipping.
Shoot me a PM and give me your particulars if your interested.
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Old Apr 26, 2012, 06:58 AM
Registered User
Joined Dec 2011
48 Posts
My T-28 Trojan was stuck in a tree for 4 days, but it finally came down and and I had a good flight tonight...but somehow the aileron channel has been reversed...when I try to roll right it rolls left and vice versa....not sure how this has happened as I havent played with the electrics at all.....I have a dx7s so will try to reverse the controls, but has anyone heard of this happening before?
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Old Apr 26, 2012, 09:30 AM
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United States, CO, Louisville
Joined Jan 2011
75 Posts
Quote:
Originally Posted by Joelster View Post
My T-28 Trojan was stuck in a tree for 4 days, but it finally came down and and I had a good flight tonight...but somehow the aileron channel has been reversed...when I try to roll right it rolls left and vice versa....not sure how this has happened as I havent played with the electrics at all.....I have a dx7s so will try to reverse the controls, but has anyone heard of this happening before?
There's been a discussion of "servo reversing" on the UM Corsair thread (a bit different, since the Corsair has 2 aileron servos and the Trojan only a single servo; the issue is the same, though). Here's a link to the page where this started, starting at post 996:
http://www.rcgroups.com/forums/showt...432230&page=67

You can reprogram the receiver to reverse the aileron servo, use a "servo-reversing cable", or just reverse the channel on your transmitter (as you mentioned). Option #3 is likely the easiest!
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Old Apr 26, 2012, 11:14 AM
Cadcyg
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United States, TX, Midland
Joined Apr 2011
187 Posts
Center of gravity

Hey all. I nose dived my UM t-28 a couple of days ago. Since every part for this great little plane is on back order I proceeded to rebuild her. With lots of glue and light weight spackle, some new paint and stickers I think it came out pretty good.
Question is the COG and the new added weight. I listed some pictures to show you how much I had to add. Does the COG look about right from the LE?
The scale read before painting around 1.75. oz. Now with the battery and the paint, etc it comes in at 2.25. Will the stock motor be able to handle this amount of weight? That is a 25oz magnet. I may not use it if will affect the receiver.
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Description: Scale showing weight without added weight

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Old Apr 26, 2012, 01:34 PM
F18
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United States, MA, Onset
Joined Apr 2008
233 Posts
Quote:
Originally Posted by Joelster View Post
My T-28 Trojan was stuck in a tree for 4 days, but it finally came down and and I had a good flight tonight...but somehow the aileron channel has been reversed...when I try to roll right it rolls left and vice versa....not sure how this has happened as I havent played with the electrics at all.....I have a dx7s so will try to reverse the controls, but has anyone heard of this happening before?
Yea...thats a pain in the butt! Had this happen with my UM Corsair when I hastily left it in my car trunk with a lipo connected overnight......the receiver logic changed as the battery fully depleted. There is a link to a transmitter manual on the HH or HZ web site that shows how to use a sequence of stick positions as you turn on your transmitter to run the receiver through all the different servo settings until you are back to the original aileron movement..... may be someone can chime in.....I don't remember all the postions.

All I know is that I could not get the receiver on the Corsair back to its original logic settings.....some control surface was always reversed even when I got the aileron response straightened out...
SO I just reset the dip switches on a HP6DSM transmitter to get the receiver/servo throws to respond correctly on the UM Corsair. Dip switch 4 to Off and switch 2 ON and the controls are corrected. When I use this transmitter with my other UMs like the T-28, 4 is ON and 2 is Off.
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Last edited by F18; Apr 26, 2012 at 01:55 PM.
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Old Apr 26, 2012, 02:45 PM
F18
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United States, MA, Onset
Joined Apr 2008
233 Posts
Quote:
Originally Posted by cadcyg View Post
Hey all. I nose dived my UM t-28 a couple of days ago. Since every part for this great little plane is on back order I proceeded to rebuild her. With lots of glue and light weight spackle, some new paint and stickers I think it came out pretty good.
Question is the COG and the new added weight. I listed some pictures to show you how much I had to add. Does the COG look about right from the LE?
The scale read before painting around 1.75. oz. Now with the battery and the paint, etc it comes in at 2.25. Will the stock motor be able to handle this amount of weight? That is a 25oz magnet. I may not use it if will affect the receiver.
Attachment 4813071

Attachment 4813072

Attachment 4813073

Attachment 4813074

Attachment 4813075
If you really want an accurate CG read......balance on the pencil points and not on the flat erasers
The plane turned out excellent!
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Last edited by F18; Apr 26, 2012 at 04:02 PM.
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Old Apr 26, 2012, 04:05 PM
Cadcyg
cadcyg's Avatar
United States, TX, Midland
Joined Apr 2011
187 Posts
Thanks but what about the questions.
Is that about right for the COG?
is the weight too much for the stock motor?

I can sharpen those pencils. Never really thought about it.
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Old Apr 26, 2012, 05:15 PM
F18
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United States, MA, Onset
Joined Apr 2008
233 Posts
Quote:
Originally Posted by cadcyg View Post
Thanks but what about the questions.
Is that about right for the COG?
is the weight too much for the stock motor?

I can sharpen those pencils. Never really thought about it.
Yes....that is the way it should look if balanced on points 30 to 32mm back from the leading edge measured at the root of the wing. From your pictures the center line of the fuselage looks completley horizontal which is good.....but balance it on points. The contact of those flat erasers with the wing would represent about a square foot of contact at full scale.

Guys have flown this plane with big 300mAh and 500mAh lipos with key chain video cameras attached that are pushing over 2oz without a problem. With that weight I would watch how aggessive you fly.....the wing load would be high and could fatigue and fold up a wing with high G stuff. But there should be no problem getting it off the ground.
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Old Apr 26, 2012, 06:47 PM
Cadcyg
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United States, TX, Midland
Joined Apr 2011
187 Posts
cool that's a good thing to know.
Do you think using a magnet is going to interfere with the radio?
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Old Apr 26, 2012, 09:31 PM
F18
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United States, MA, Onset
Joined Apr 2008
233 Posts
Quote:
Originally Posted by cadcyg View Post
cool that's a good thing to know.
Do you think using a magnet is going to interfere with the radio?
Introducing a rogue magnetic field around anything that is electronic is not ideal.
It would be easy to bench test it while the magnet is on or near it and see if their is any glitches in the radio control imputs.

It would be better to use coins or clay/putty to balance the plane than the magnet.
Its critical to get these little planes balanced no matter what you use to do it.

let us know how it flies when you get it out again! At that weight landing is going to be hot/fast and the plane will certainly not be as lively as out of the box....but the added weight should be a benefit in the wind
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Old Apr 26, 2012, 10:16 PM
Cadcyg
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United States, TX, Midland
Joined Apr 2011
187 Posts
Cog found

Thank you to everyone who responded. I found some bamboo sticks from the dollar tree store. I went with penny's taped together. It is exactly 32 mm from the LE. Once I get a calm day I will take her out. So far the winds have been in the 10-20 mph range blustery.
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Old Apr 27, 2012, 09:22 AM
F18
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United States, MA, Onset
Joined Apr 2008
233 Posts
Quote:
Originally Posted by cadcyg View Post
Thank you to everyone who responded. I found some bamboo sticks from the dollar tree store. I went with penny's taped together. It is exactly 32 mm from the LE. Once I get a calm day I will take her out. So far the winds have been in the 10-20 mph range blustery.
Attachment 4814877
Yep....those bamboo scewers or even the chop sticks from your favorite Chinese restaurant are perfect for a simple CG Balance jig. Just super glue them to the side of a scrap block of wood at the right spacing and your in business.

My wife thinks I am crazy.......I never throw away my bamboo chop sticks when I leave a Chinese restaurant. They can be used for so many things in this Hobby
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Old Apr 27, 2012, 09:28 PM
RC pilots do it in the air
marke14's Avatar
Joined Dec 2011
114 Posts
cadcyg, your COG test stand is the simplest one I have seen - absolutely brilliant, I love it and am so jealous I didn't think of it.
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Old Apr 27, 2012, 10:02 PM
that's gonna leave a scar
KCinNC's Avatar
Marina Village, NC
Joined Aug 2007
3,296 Posts
Quote:
Originally Posted by cadcyg View Post

is the weight too much for the stock motor?
i painted just the tail & nose of my um P-51..which uses the same motor as the um T-28

i could not get the balance right at all....flew really twitchy
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Old Apr 28, 2012, 04:43 AM
Registered User
New Zealand, Canterbury, Rolleston
Joined Oct 2011
898 Posts
The bamboo skewers have fixed the wing flexing problem. So I now need some more for CoG testing it seems. Fortunately we have a whole packet of them somewhere...

Only other problem yesterday was swallows. Got up to about 5 of them circling round. Crashed while chasing them or them me - fortunately into very long grass.
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