HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Oct 14, 2009, 08:09 PM
Gone Flying.
ChrisWNY's Avatar
Western NY
Joined Nov 2006
2,401 Posts
Tail servo installed

All I had time for tonight was the tail servo installation. There are a few different ways to mount the tail servo, I simply followed the diagram in the T-Rex 500 manual. It was fairly straight forward, though I ended up using #2 (2-52) 0.5" long stainless steel bolts with hex nuts and washers to mount the servo to the mounting clips on the boom. The servo clips that were included with the HK-500GT kit don't quite line up with the holes on the round mounting clips on the tail boom, so I decided not to use them.

These small #2 stainless bolts (pictured below) can be purchased at local hardware stores, they ran me about $0.85 each with the washer and hex nut included. Ironically the #2 bolts threaded perfectly into the predrilled holes on the round servo clips that attach to the boom, they threaded right in quite securely.

The small square servo clips appear to have been intended for the tail servo (as well as the frame servos), and perhaps there were other ways to get the screw holes to line up, but trusty bolts with some blue Loctite (I used the rubber servo grommets included with the TowerPro MG930 servo, they'll reduce vibration and help keep the bolts from loosening) are a good option for mounting a tail servo, they should hold firmly from here on out.
ChrisWNY is offline Find More Posts by ChrisWNY
Last edited by ChrisWNY; Oct 14, 2009 at 08:18 PM.
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 15, 2009, 07:19 AM
Gone Flying.
ChrisWNY's Avatar
Western NY
Joined Nov 2006
2,401 Posts
One thing to clarify about the cyclic servo installation - frame spacers are NOT needed for the TowerPro MG930 servos installed in the front of the HK-500GT frame because they fit perfectly without making contact, unlike other servo brands which require spacers to fit into the EXI 500 frame. I'm not sure if the frame dimensions are any different on the HK-500GT compared to the EXI 500 (I'm assuming they are identical since both are "T-Rex 500 compatible"), but I know some of the Hitec digitals (such as the 5245) will not fit into a T-Rex 500 frame without spacers.

Finless Bob recommends NOT using the rubber grommets for the servo. I however used them anyway as they do reduce vibration to the servo, and if you wrench them down tight enough, wobble won't be a factor in the slightest sense. Finless Bob sometimes goes over the edge with his recommendations; IMO not using the grommets is a poor idea for many reasons (i.e. minimizing vibration on the servo as to not loosen the servo screws during flight). It's not just Nitro heli's that vibrate, electric heli's vibrate as well, hence the need for using blue loctite on any frame screws that thread into metal.
ChrisWNY is offline Find More Posts by ChrisWNY
Reply With Quote
Old Oct 15, 2009, 12:47 PM
Registered User
USA, NC, Hendersonville
Joined Sep 2007
71 Posts
Looks good!

I have Hitec 5245 MGs on my cyclic and needed the spacers. The bolts that came with my EXI kit weren't long enough to use with the spaces so I bought 2mm X 10mm replacements.

I didn't use the servo grommets. I think that Finless and other 3D pilots want to make sure there's no servo movement possible. For sport flying, which is all I ever plan to do, the grommets probably help make the servos last longer.




RCForever is offline Find More Posts by RCForever
Reply With Quote
Old Oct 15, 2009, 05:07 PM
Gone Flying.
ChrisWNY's Avatar
Western NY
Joined Nov 2006
2,401 Posts
RC -

The EXI looks sharp. The head really does look similar to the HK-500GT, looking from the top view of the rotor head in that photo.

Out of curiosity, what is the optimal head speed for these 500 sizers? I'll be using a Scorpion HK-3026-1600Kv motor, 14T pinion, on a 6S LiPo pack. My CC Phoenix 80-Amp ESC arrived today, and I'd like to set up the governor to limit the head speed to specific RPMs so that it doesn't spin up out of control (at 3000 RPMs) like others have stated. Right now I have it set at 2200 RPMs at 0-50% throttle, 2400 at 50-99%, and 2500 at 100%. I always assumed head speed would be slower on a 500-size, I run my HK-450 at around 2500-2600 RPMs.
ChrisWNY is offline Find More Posts by ChrisWNY
Reply With Quote
Old Oct 15, 2009, 05:39 PM
Registered User
USA, NC, Hendersonville
Joined Sep 2007
71 Posts
Idownloaded a speadsheet that Finless Bob created that showed varios combos of motors and pinions. It showed a 1600 KV with 14T createing a HS of 2892. With a governed ESC you can reduce this. My Scorpion 1210 KV motors with the 16T pinions I ordered will turn 2499 HS.

I plan to set both my EXI 500s up to the point of test hovering them, then setting them aside until I have more sim time and time on my 550 sized Century Swift 16 trainer.

Early this year I built two Align Trex 500 ESPs, then sold them. I think that the quality for the price of these 500s is GREAT. Plus the belt driven tail is more durable than the torque tube and I hope that the aluminum frame will not have the static discharge problems associated with the CF frame versions.

Good luck with yours!
RCForever is offline Find More Posts by RCForever
Reply With Quote
Old Oct 15, 2009, 06:26 PM
Gone Flying.
ChrisWNY's Avatar
Western NY
Joined Nov 2006
2,401 Posts
Thanks for the info - I know CastleLink stated that a 2400-2500RPM governed head speed was about 80% or so throttle, so a max head speed of 2892 RPMs on 14T seems about right. Here I thought that 1800-2000 RPMs would be tops for a 500, didn't realize the head speed on a 500 sizer would be nearly the same as (if not higher than) a 450.
ChrisWNY is offline Find More Posts by ChrisWNY
Last edited by ChrisWNY; Oct 15, 2009 at 06:47 PM.
Reply With Quote
Old Oct 15, 2009, 08:20 PM
trx
Registered User
Joined Apr 2008
324 Posts
RCForever, when you built your trex500 esp, did you have to ground the cf frames to avoid static discharge? I'm planning of building one myself, soon. for now just gathering relevant info. thanks in advance.
trx is offline Find More Posts by trx
Reply With Quote
Old Oct 15, 2009, 08:24 PM
Registered User
Evan D's Avatar
Charlotte, NC
Joined Jan 2004
5,551 Posts
The static was from the belt, since the ESP doesn't have a belt, no static. People saying the ESP has a static problem are having other issues...

No need to ground between sections...
Evan D is online now Find More Posts by Evan D
Reply With Quote
Old Oct 15, 2009, 08:28 PM
trx
Registered User
Joined Apr 2008
324 Posts
Okay great, thanks Evan D.
trx is offline Find More Posts by trx
Reply With Quote
Old Oct 15, 2009, 09:31 PM
Gone Flying.
ChrisWNY's Avatar
Western NY
Joined Nov 2006
2,401 Posts
A few spritzes of a silicone-based lubricant can help prevent belt static, avoid petroleum-based products as they can cause rubber to deteriorate more rapidly over time. However, it's only a temporary fix. Some guys will run wire from the boom to the negative lead on the ESC, but in all honesty running a wire connecting the boom to any area of the frame should be more than adequate. The T-Rex Wikipedia write-up specifically mentions the T-Rex 500 as being especially susceptible to static issues...

http://en.wikipedia.org/wiki/T-Rex_%28RC_helicopter%29
ChrisWNY is offline Find More Posts by ChrisWNY
Reply With Quote
Old Oct 16, 2009, 04:19 AM
Private Pilot
Twister773's Avatar
Joined Jul 2009
1,226 Posts
just ordered one
Twister773 is offline Find More Posts by Twister773
Last edited by Twister773; Oct 16, 2009 at 06:04 AM.
Reply With Quote
Old Oct 16, 2009, 06:51 AM
Gone Flying.
ChrisWNY's Avatar
Western NY
Joined Nov 2006
2,401 Posts
Yep, as of this morning (EST), HobbyCity has 255 in-stock...
ChrisWNY is offline Find More Posts by ChrisWNY
Reply With Quote
Old Oct 16, 2009, 07:40 AM
trx
Registered User
Joined Apr 2008
324 Posts
Can I use an AR6100 receiver on this size of heli (500)?
trx is offline Find More Posts by trx
Reply With Quote
Old Oct 16, 2009, 08:23 AM
Registered User
Evan D's Avatar
Charlotte, NC
Joined Jan 2004
5,551 Posts
You can but I wouldn't. I would use the 6200 so you have the extra satellite.
Evan D is online now Find More Posts by Evan D
Reply With Quote
Old Oct 16, 2009, 09:21 AM
Gone Flying.
ChrisWNY's Avatar
Western NY
Joined Nov 2006
2,401 Posts
I've NEVER heard of people having issues with the AR6100's on heli's, I know several guys who use the AR6100's on the much larger 600 sizers and have had 0 issues, no hiccups, no glitches, nothing but 100% reliable operation.

Is the 6200 a safer bet? Perhaps, but it's nearly twice the cost, so if you're trying to build a 500 on a budget, the cost of the 6200 over the 6100 might be significant. You can pick up the AR6100's on ebay shipped free from Hong Kong for $43 now brand new (OEM packaging, no binding plug). The lowest prices I've seen on AR6200 is $80 (plus shipping), brand new.
ChrisWNY is offline Find More Posts by ChrisWNY
Last edited by ChrisWNY; Oct 16, 2009 at 09:29 AM.
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
I got some Fan Fold what to build thread part II started by emoone!!! Don Sims Foamies (Kits) 188 Jan 23, 2010 08:28 PM
Mountain Models Tantrum Partial Build Thread.. Tram Parkflyers 142 Apr 03, 2004 10:41 PM
My Bobolink Build Thread (very Colibri like) Jim Poor Hand Launch 65 Dec 10, 2003 04:48 PM
Laird Super Solution Build Thread! boomerace Parkflyers 178 Oct 29, 2003 07:20 PM
Switchback re-build thread (or What the $#*& was that!) Biggles604 Parkflyers 17 Jun 23, 2003 09:34 PM