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Old May 04, 2006, 07:06 AM
Dan Murphy
USA, MA, Hopkinton
Joined Mar 2006
417 Posts
Help!
T-Hawk is failing range test

So, I get up early to get a few flights in before work. Head down to the field, put everything together, and start going thru pre-flight. Everything looks good, and I start a range test. Not so good.

Here's what I'm doing:
1. fully collapse antenna on tx
2. the plane is sitting on a stone wall, with the tail pointing directly at me so I can see the elevator and rudder move.
3. I start walking away, moving the control stick and checking the plane.
4. When I get only about 25-30 feet away, things go whacko. The motor starts kicking in, and the control surfaces start fluttering on their own

I did this a number of times with the same results. I don't remember the plane being like this on previous range tests.
At 30 feet, when I extend the antenna, things get better.
However, with the antenna extended and standing about 80 feet away, I can see the engine kicking in.

The plane battery was fully charged
This actually happened on Monday, too, and I figured that maybe the tx batteries were low, so they were charged last night

So, no flying - bummer. Hate to see the plane crashed or ending up in a tree for a stupid reason.

Being new at this (about a month), what are the possible causes? I figure either the tx or the rx, since all the functions (motor, elev and rudder) are affected. Is there a way to diagnose for sure what's wrong? I've got a friend with a t-hawk also, with the same channel, so I can grab his stuff and test with his tx, and see how my tx works with his rx.

I've only had the plane for about a month, and the rx is only a few weeks old because I got a whole new fuse with electronics after I put the plane in a lake . Is this a common failure?


merlinmurph
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Old May 04, 2006, 07:41 AM
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Is the Rx antenna properly attached and routed? Separated from servos, etc? Has that Rx ever worked properly since new? Could there be some local interferance (try testing in a different location)? Is there a crystal module that may be loose? I have read that the T-Hawk radio equipment is not the very best available and it could just be a bad one. Good luck.
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Old May 04, 2006, 08:03 AM
Dan Murphy
USA, MA, Hopkinton
Joined Mar 2006
417 Posts
Yes, the rx has range tested and worked fine previously. Also, I'm in the same field where I have flown in the past with no problems.

Thanks, I should check for loose stuff in both the rx and tx. I had an unplanned landing (actually, two unplanned landings) last week while flying in a bit of wind and that may have shook things up a bit.

I'm sure the electronics in these RTF packages aren't quite up to snuff with the name brand stuff, though I haven't seen too many comments about people having issues with t-hawk electronics.

Thanks,
merlinmurph
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Old May 04, 2006, 09:59 AM
Oldie but goodie
Popsflyer's Avatar
United States, CA, Orange
Joined Jun 2003
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Quote:
Originally Posted by merlinmurph
I'm sure the electronics in these RTF packages aren't quite up to snuff with the name brand stuff, though I haven't seen too many comments about people having issues with t-hawk electronics.

Thanks,
merlinmurph
You answered your own question.

My suggestion is to return the newly purchased Fuselage/electronics assembly and have it exchanged for another. Stuff happens.
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Old May 04, 2006, 12:53 PM
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Considering that the new electronics were fine before they were crashed twice, I don't think a return is appropriate, but you could ask the company.
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Old May 04, 2006, 04:25 PM
Dan Murphy
USA, MA, Hopkinton
Joined Mar 2006
417 Posts
Here's my plan: I'm going to try the rx in the fuse that got dunked in the lake and see if that works.

If that doesn't solve anything, tomorrow I can try my friend's stuff. That should narrow it down.
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Old May 04, 2006, 06:05 PM
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Rock Hill, SC
Joined Oct 2002
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Quote:
Originally Posted by merlinmurph
Here's my plan: I'm going to try the rx in the fuse that got dunked in the lake and see if that works.

If that doesn't solve anything, tomorrow I can try my friend's stuff. That should narrow it down.
A hard landing can possibly jar the crystal loose in the receiver, even damage the crystal. This can happen to any receiver, not just that used by the T-Hawk. Your statement about "dunked in the lake" implies the plane made an "unscheduled" landing in water. If so, you need to remove the receiver and the speed contol and thoroughly dry them out. Good time to check on the crystal.

I have experienced glitching with my stock T-Hawk, with the 27 mHz FM receiver, but never the glitching you have reported. No need to swap out electronics righ away. Check the condition of the existing equipment first.

Good Luck!

RD
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Old May 04, 2006, 07:41 PM
Dan Murphy
USA, MA, Hopkinton
Joined Mar 2006
417 Posts
The plane that ended up in the lake has been replaced by a new fuse and all the electronics, and is only 2 weeks old. I checked the receiver and made sure everything was securely plugged in. It still failed a range test.

Tonight, I got home, grabbed the old fuze (that was dunked) and range tested it. It failed the same way.

Tomorrow I'll know more when I check it with the other t-hawk.
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Old May 04, 2006, 08:01 PM
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Quote:
Originally Posted by merlinmurph
The plane that ended up in the lake has been replaced by a new fuse and all the electronics, and is only 2 weeks old. I checked the receiver and made sure everything was securely plugged in. It still failed a range test.

Tonight, I got home, grabbed the old fuze (that was dunked) and range tested it. It failed the same way.

Tomorrow I'll know more when I check it with the other t-hawk.

Since your having the same trouble with both set ups I would look at your transmitter as a possible source of your trouble. Granted one reciever is questionable since it went swimming. I know you said you charged your tx batteries, but are they showing fully charged on a volt meter?

Also what about the T hawks battery. Are you using the same battery that was in the crash, did it get wet? Is it's voltage ok when fully charged.

Just a couple of things to look at.

Doug
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Old May 04, 2006, 08:31 PM
Hold my beer and watch this!
Jeremy Z's Avatar
Northern IL
Joined Oct 2005
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I bet it's time to replace your transmitter batteries.

That, or you're getting interference from someone's old cordless phone or baby monitor.
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Old May 04, 2006, 08:44 PM
Dan Murphy
USA, MA, Hopkinton
Joined Mar 2006
417 Posts
Tx batteries were charged last night and there is nothing near this site. The closest house is at least a mile away
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Old May 04, 2006, 09:29 PM
Elfi Flyer
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Rock Hill, SC
Joined Oct 2002
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Quote:
Originally Posted by Jeremy Z
I bet it's time to replace your transmitter batteries.
That, or you're getting interference from someone's old cordless phone or baby monitor.
From past memory, earlier cordless phones worked in the 49 mHz range, as did baby monitors, thereafter the jump to 2400 mHz. So, I am surprised to hear this could be an interference problem on a 27 mHz receiver. From what has been described, it sounds like transmitter related problems.

RD
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Old May 05, 2006, 04:19 AM
Hold my beer and watch this!
Jeremy Z's Avatar
Northern IL
Joined Oct 2005
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Quote:
Originally Posted by Doug Sipprell
From past memory, earlier cordless phones worked in the 49 mHz range, as did baby monitors, thereafter the jump to 2400 mHz. So, I am surprised to hear this could be an interference problem on a 27 mHz receiver. From what has been described, it sounds like transmitter related problems.

RD
You're right, it was 49 MHz. What am I thinking of besides toy RC that works in that range? Walkie-talkies?

Just for the heck of it, you might try putting alkalines in it. That design may need the higher voltage.

You didn't accidentally sever the antenna when you were putting that tiny tail bolt through the tail boom, did you?

If it turns out to be neither of those things, I'd suspect the cheap receiver over the cheap transmitter. They would get replaced together, so it is a moot point, I guess.

My old T-Hawk is in my dad's hands now. It's got a Hitec Micro 05S receiver, being controlled by a Hitec Flash 5 radio.
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Old May 05, 2006, 11:45 AM
Elfi Flyer
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Rock Hill, SC
Joined Oct 2002
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Quote:
Originally Posted by Jeremy Z
My old T-Hawk is in my dad's hands now. It's got a Hitec Micro 05S receiver, being controlled by a Hitec Flash 5 radio.
I really can't fault the original electronics of my first T-Hawk. They survived a few harsh landings and at least one dorking in. However, I did wish the "resolution" of the throttle control was better. When building T-Hawk #2, I went with "standard" 72 mHz electronics (FMA Extreme 5 Rcvr) in addition to Hitec HS55 servos. The servo upgrade was really not needed, but the change to the 72 mHz really did help in eliminating glitching and providing a smoother input for throttle, rudder, and elevator. I should say, I only got the glitching at our club site, and we have a notoriously noisey telephone pole transformer at one end of the field. When ever near it, I would get the glitching. Elsewhere, the stock T-Hawk electronics worked quite well.

RD
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Old May 07, 2006, 07:31 PM
Dan Murphy
USA, MA, Hopkinton
Joined Mar 2006
417 Posts
Update: Finally got to do some equipment tests with another t-hawk. I was hoping to do this Friday, but a stomach virus changed those plans.

I had two transmitters - mine with fresh batteries and my friend's tx. I did a range test with my tx and it failed miserably again. I did a range test with the other tx, and it worked fine.

I'll give the t-hawk guys a call tomorrow.

End of story.
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