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Old Sep 01, 2008, 07:03 PM
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TimJohnson's Avatar
United States, CA, Rancho Santa Margarita
Joined Jul 2006
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I wonder if you glued the tail feathers on evenly? My F-4 does not have any tail wag. So that has me wondering as well. Take a good look at the tail.
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Old Sep 01, 2008, 09:54 PM
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flyingrandy55's Avatar
USA, TX, Keller
Joined Apr 2006
487 Posts
I have to agree with you two. It does need just a bit more speed! It takes an effort to climb out with 3s. What kinda amps on 4s with the stock motor and fan?

R
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Old Sep 01, 2008, 10:21 PM
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United States, CA, Rancho Santa Margarita
Joined Jul 2006
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Randy, can you measure your AMP and Watts on your F-4? I am curious.
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Last edited by TimJohnson; Sep 02, 2008 at 11:02 AM.
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Old Sep 01, 2008, 10:23 PM
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cray2602's Avatar
Plain ole KS
Joined Jan 2008
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Stock motor and fan on 4s pulls 25amps. It runs excellent on 4s, but my stock motor gave up after four flights on 4s. Tim said his ran about 40 flights on 4s before killing the motor so who knows. Climb out on 4s is too easy, just give it a very light throw and it will climb up at about 60deg accelerating all the way up. It has unlimited vertical on 4s. If you go 4s get the lightest battery you can that will hold voltage at 25amps, mine weighs a bit much and i had to move it so far back the rear of the battery touches the servos and i still had to add tail weight to get it back to stock CG.
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Old Sep 09, 2008, 08:34 AM
I hate waiting for parts
Mike_Then's Avatar
United States, NC, Garner
Joined Apr 2001
6,680 Posts
A very disappointing maiden...

I started on my Kyosho F-4 on Sunday at 11:00. It was ready to fly at 1:30 PM, 2.5 hours later. It took that long because I had to hog out some foam where the receiver sits.... the canopy wouldn't latch into place because the servo plugs were touching the canopy. I also ran the fan up slowly before gluing the wing in place, to make sure there were no problems. I remembered reading a few people here that had issues with their stock fans (thrown blades, scrubbing, etc.). Mine ran up fine but with a bit of vibration. I tried it with and without the spinner on the front of the fan... the spinner seemed to make it vibrate slightly less, but I went with the spinner anyway.

Took it to the field and it was severely nose-heavy. I mounted the battery as far as it would go, without hogging out any foam, and had to add 1/2 oz. of lead to the tail. Checked my elevons and they were backwards! I swore I set them right but I'm glad I ALWAYS pre-flight every airplane. Set them correctly, range check OK, and a friend hand-launched.

That fan sure makes a lot of noise with not a lot of go-power... While I didn't expect it to be a speed demon, I was expecting more thrust than what it provided. It was also severely nose-heavy, as I had to add A LOT of up-trim. It was porposing up and down a lot, and I never got the jet on-step. Just as I was checking the trim to see if I at least got the up/down set right, the F-4 all of a sudden turned hard-right and straight down into the beans it went.

NTSB was very pleased to find the F-4 in one piece, nose-down in the beans. Except for some minor scratches/missing foam, the plane was intact. If that happened over the runway, this story would have a much different outcome. The reason for the sudden crash was because the "elevator" (left) servo went to full down deflection and locked there.... bad servo. The other one operates fine in either channel on the receiver, and the bad servo doesn't operate at all.

While I have been very pleased with Kyosho's products, I'm disappointed in the servos they chose for their PIP planes. So the question is, do I simply rip out BOTH servos (I don't trust the other servo) and install some tried-and-true HS-55's, or do I call Kyosho and let them know? Also, the balance point in the manual is questionable - in my opinion - as once I added lead to the tail, it balanced right on the money and it was still nose-heavy.

My first flight with this plane did NOT justify the price paid. I sure hope the 2nd flight is better.
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Last edited by Mike_Then; Sep 09, 2008 at 09:08 AM.
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Old Sep 09, 2008, 10:10 AM
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cray2602's Avatar
Plain ole KS
Joined Jan 2008
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Sorry to hear about your crash. My stock servos havent glitched at all, thankfully. Im a bit disapointed with the price of this model as well. Its a nice little plane but for almost $200 i wont be buying anymore Kyosho planes. If they sold them in airframe only or no electronics versions i would definately buy more. For $200 you can buy a much larger plane and still get everything but a radio and rx. Look at the GWS planes, $65 for a normal sized airframe only kit.
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Old Sep 09, 2008, 10:30 AM
The thruster don't work!
Roy E Oetting's Avatar
Fairborn, OH
Joined Oct 2002
414 Posts
Mike, It sure sounds like your CG is to far aft. Moving it forward will tame the porpoise.
Roy
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Old Sep 09, 2008, 11:54 AM
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flyingrandy55's Avatar
USA, TX, Keller
Joined Apr 2006
487 Posts
Quote:
Originally Posted by TimJohnson
Randy, can you measure your AMP and Watts on your F-4? I am curious.
Yes Tim I will do it this weekend. I have flown it a total of 5 flights now. 1 flight took the nose off(nose heavy on landing). The other 4 were ok. If it had a bit more power it would be a lot more fun. As it is I have to fly it at full power all the time! I am not giving up on it yet Tim.

R
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Old Sep 09, 2008, 12:00 PM
I hate waiting for parts
Mike_Then's Avatar
United States, NC, Garner
Joined Apr 2001
6,680 Posts
It certainly could have been worse, so I'm thankful for that. It's interesting to see that in all of the years I've been flying, I can count the number of in-flight failures on one hand. One was due to flutter on a large propjet that destroyed the elevator servo (my fault), and the other was an aluminum engine mount breaking in flight which sent a still-running .91 four-stroke into the leading edge of the wing (not my fault, actually landed the airplane!). This is only the 3rd so maybe I should count my blessings. This experience, however, will make me think twice before purchasing something else with preinstalled servos.

I called Kyosho and they were very nice and more than willing to help, but of course they require a receipt to replace the servo. The problem is I bought the plane at a swap shop (new in box, from a hobby shop) and was not provided a receipt. I can call the guy, as he left me his business card, but it's not worth the trouble for one sevo. I'll pull them out and install some HS-55's and cut my losses.

@Roy - I wasn't clear before, sorry about that. It was porpoising because it was severely nose heavy and I was fighting the elevator stick trying to trim it out. It did not behave like it was tail heavy.
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Old Sep 09, 2008, 01:21 PM
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Plain ole KS
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Mike , what size lipo were you using? I ran mine on stock setup a couple times with a 1300mah battery and it flew way nose heavy and wasnt able to pull the nose up at landing speed. Keep her light if you stay with the stock power setup.
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Old Sep 09, 2008, 01:53 PM
I hate waiting for parts
Mike_Then's Avatar
United States, NC, Garner
Joined Apr 2001
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My only choice was my MaxAmps 3s 1290. The other two packs I have (MaxAmps 3s 1100 and DN 1350) didn't really fit. It was very very nose heavy with the 1290. I added 1/2 oz. to the tail and can probably add another 1/4 oz. and be OK.
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Old Sep 09, 2008, 02:52 PM
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Plain ole KS
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I would make a battery tray like FlyingRandy did and slide your battery back, then mount the rx up front where the batt was. That way you can get the CG right without having to add tail weight. I think page 10 shows FlyingRandys tray mod and my over engineered battery box mod for my heavy 4s setup.
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Old Sep 11, 2008, 11:51 AM
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Joined Sep 2004
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I managed to come across one for $50, but I had to add a lot of weight to the tail to get it to balance with a 3S Flightpower 1345. Here's the vid:

http://jp.youtube.com/watch?v=gZqilFHG0S0
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Old Sep 11, 2008, 12:19 PM
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TimJohnson's Avatar
United States, CA, Rancho Santa Margarita
Joined Jul 2006
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Oh nice!!! I love your hand launch...LOL I see you found that this airplane loves to be low to the ground...LOL I found this to be the same.
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Old Sep 11, 2008, 12:37 PM
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Plain ole KS
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Nice vid! Cool launch, i would have trashed it if i tried that.
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