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Sep 07, 2016, 09:59 AM
Registered User
thanks for the explanations.
so, what's the difference between adding some shims to change the angle of incidence of the horizontal stab vs simply trimming the elevator?
-beanie
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Sep 07, 2016, 10:16 AM
I'd rather be flying!
turboparker's Avatar
Beanie,

Compensating for a decalage problem with elevator trim reduces elevator effectiveness in the direction of the applied trim.

It's best to get the airframe sorted-out as well as possible (thrust-line, decalage, CG) before using tx trim. It's called good engineering practice. Here's an excellent flight-trimming chart, courtesy of the NRCA. Be sure to follow the steps in order, as some adjustments are interactive:

https://nsrca.us/index.php/lists/519.../177-trimchart

Joel
Latest blog entry: E-flite 850mm Pitts
Sep 07, 2016, 10:24 AM
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bhoov128's Avatar
It also causes the plane to fly "dirty" with unnecessary drag. These warbirds don't have an abundance of power and I noticed the fix on my P-47 of shimming vs. trimming actually did make a difference in performance.
Sep 07, 2016, 10:49 AM
Oh! Just love model
K5083's Avatar
Although turboparker and bhoov128 are 100% correct, you may find that you are happy with the performance after correcting with trim, and you may prefer not to cut up your plane. If you can live with the guilt of not exercising good engineering practice, I promise not to tell anyone!

August
Sep 07, 2016, 11:51 AM
Registered User
thanks guys. that helps a lot.
what batteries are most of you using? i'm using a 220mah or 210mah battery and so i think i may be a little tail heavy, hence worsening the decalage issue. are you all using the 280mah standard battery?... are there any better alternatives?
-beanie
Sep 07, 2016, 11:55 AM
Registered User
turboparker,
thanks for that link. it's an awesome resource. looks like i have a lot of testing to do!
-beanie
Sep 07, 2016, 11:58 AM
"Is That a Drone"
ebolton92's Avatar
Quote:
Originally Posted by beanie
thanks guys. that helps a lot.
what batteries are most of you using? i'm using a 220mah or 210mah battery and so i think i may be a little tail heavy, hence worsening the decalage issue. are you all using the 280mah standard battery?... are there any better alternatives?
-beanie
If you think its flying tail-heavy move the battery forward, you can use pretty much any size battery as long as you position it so the CG is correct.

On that note if it were tail heavy you would need to add up trim to push the nose down so then when you sped up it would nose dive, if you are having climbing issues when going full throttle then i highly doubt being tail heave is the cause. (PS nose heavey would cause the climbing as you would need to add down trim to keep the nose up)
Sep 07, 2016, 12:09 PM
Custom User Name Title
bhoov128's Avatar
Quote:
Originally Posted by beanie
thanks guys. that helps a lot.
what batteries are most of you using? i'm using a 220mah or 210mah battery and so i think i may be a little tail heavy, hence worsening the decalage issue. are you all using the 280mah standard battery?... are there any better alternatives?
-beanie
If I'm flying mine on 2S then I usually use hyperion G3 CX 240mAh packs.
Sep 07, 2016, 05:15 PM
Registered User
JimLindner's Avatar
Skyhawker,

Very nice job, I see no evidence of the wires at all. How did you accomplish this, or did I just miss the wire channel. If you do not mind what was the LED number you used.

Jim
Sep 07, 2016, 08:35 PM
Registered User
SkyHawker's Avatar
Quote:
Originally Posted by JimLindner
Skyhawker,

Very nice job, I see no evidence of the wires at all. How did you accomplish this, or did I just miss the wire channel. If you do not mind what was the LED number you used.

Jim
Thanks Jim.

I used a 1/8" aluminum tube with the end sharpened and very carefully drilled holes to where the servos are. I removed the tape and the scoop as well then ran the wires in the channel and put new tape back on. I used 1206SMD LED's wired in series with 30 AWG Solid Core Kynar wire and a 20mA LED Driver to power all 3 LEDs from the brick battery power.

To make the tube, you take a No. 11 Exacto blade - you cut away the INSIDE edge of the tube end to create a sharp knife like circle... then you just twirl the tube as a cutter.

I got everything from here LightHouse LEDs
Sep 07, 2016, 10:39 PM
Registered User
JimLindner's Avatar
Quote:
Originally Posted by SkyHawker
Thanks Jim.

I used a 1/8" aluminum tube with the end sharpened and very carefully drilled holes to where the servos are. I removed the tape and the scoop as well then ran the wires in the channel and put new tape back on. I used 1206SMD LED's wired in series with 30 AWG Solid Core Kynar wire and a 20mA LED Driver to power all 3 LEDs from the brick battery power.

To make the tube, you take a No. 11 Exacto blade - you cut away the INSIDE edge of the tube end to create a sharp knife like circle... then you just twirl the tube as a cutter.

I got everything from here LightHouse LEDs
Thanks, on my P47 the American Flag decals covered the wiring to the LED's. Next time I will try your method, though I suspect a lack of patience on my part might get me in trouble!

Jim
Sep 08, 2016, 12:41 AM
Registered User
Quote:
Originally Posted by beanie
thanks guys. that helps a lot.
what batteries are most of you using? i'm using a 220mah or 210mah battery and so i think i may be a little tail heavy, hence worsening the decalage issue. are you all using the 280mah standard battery?... are there any better alternatives?
-beanie
My favorite 2s batteries for the P-47 are the 300mah Nanotechs. They are like $5.

Or you can go the 3s route and get some 180mah babblebats from Roger. That is my preferred option!
Sep 08, 2016, 12:56 AM
Registered User
treehugger's Avatar
hey Beanie

Another possibilty to get rid of the decalage problem is just to remove and reinstall the horizontal stab correctly with the right incidence, it's not hard at all to do.
Anyway, it's more efficient (and more 'relaxing' to your fuselage) than to screw up the beautifull line of a mustang ( which is blasphemy ) ,even if it's a small umx ...
Last edited by treehugger; Sep 08, 2016 at 12:59 AM. Reason: misspelling
Sep 10, 2016, 03:10 PM
aka ShadowVFX
Suko's Avatar
Hi everyone. I just picked this bird up from someone at a swap meet. It's brand new in box and has never been flown, but I got it at a killer price because the rudder isn't responsive.

Now, I want to get in there and see what might be wrong with it, but before I do, does anyone know of a video showing the inside of this thing before I go tearing into it? Google searches didn't come up with anything, but I thought I'd try asking here just in case.

I apologize in advance for this next question. I know that it's probably been asked on here a dozen times already, but using the search feature didn't come up with anything useful. I'll need to get a battery (or 3) for this bird. I don't own any at the moment and loath to pay HH's prices for batts. I figured I could just grab some from HobbyKing, but I have a question:

1) Do you all use an adapter to connect the JST plugs on batteries to whatever connector HH is using on the plane? Or do you just use the balance plug to connect the batt to the plane?

2) Is this the right converter cable to connect a standard battery JST plug into whatever is on the UMX P-51 BL?
http://www.rc-connectors.com/index.p...roducts_id=256

Thanks for any help you guys can offer. It's really appreciated.
Last edited by Suko; Sep 10, 2016 at 06:54 PM.
Sep 10, 2016, 05:14 PM
Registered User
Quote:
Originally Posted by treehugger
hey Beanie

Another possibilty to get rid of the decalage problem is just to remove and reinstall the horizontal stab correctly with the right incidence, it's not hard at all to do.
Anyway, it's more efficient (and more 'relaxing' to your fuselage) than to screw up the beautifull line of a mustang ( which is blasphemy ) ,even if it's a small umx ...
thanks. any advice or links to how to go about doing this?
-beanie


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