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Old 09-08-2005, 04:55 AM
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Ali
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Default RE: Skymaster Hawk Once Again (at least!)

Ron Hi,
I am on Hawk number 4 now (all 3 previous were sold on RTF) On hawk no.3 I had some real problems with flame outs after lots of slow rolls and inverted. The problem came from the clunk not following fuel around in aeros. I do use a UAT but the problem is that a UAT is quite small and it doesn't take long before the air build up was too great to allow the engine to keep running.
I was puzzled as I had never had a problem before, so I thought there must be something wrong. It turned out to be the fact that I had replaced the tubing that came in the kit for the tank install with original Tygon. The proper Tygon is thicker and less flexible which was not good for the Hawk tanks. Also I had pushed the tube through the fuel tank bung a long way into the tank. My thoughts were that I would have more tube for the tygon to rest on this reducing any chance of it coming off inside the tank. Again the problem here was that had made the tygo go through quite a sharp 90 deg bend to reach the bottom of the tank. Again reducing the flexibility of the clunk line. Once I changed the tygon to the original tubing and set up my tubes through the bung so that they were not all the way into the tank I added a lead washer to the clunk to increase the weight of it. This has now given me a air free system. After 12 mins of non stop areos including extended inverted my UAT has a tiny (and I mean tiny) air bubble.
As for rudder servo.
I have been using the Hitec HS 5125 Thin wing servo with good effect. My flights include some sustained knife edge and the odd flick at the top of a loop. At no time do I feel any rudder blow back or lack of control. Having said this my latest hawk has just been re-engined with a wren 54 and while I was there I decided to change the rudder servo. I was never happy with the amount of slop in the 5125 gears. It was always in the back of my mind and held me back from doing as much high speed stuff as I would like.
The problem I have is what servo to put in it's place. JR make the DS161 which from what I can tell is the same servo. But the 161 comes with a nasty plastic servo arm that has so much flex on it that I would be worse of than with the Hitec.
I am just waiting for a JR 3301 servo to arrive. If that fits easily I will give that a go.
I would love to put a 8411 on the rudder but I just dont want to add any more weight to the back end of this model, plus my linkage is already set up for a servo in the fin.
Janne: How did you mount the 225. Do you have any pics?
Hope this has been of help. Any questions please feel free to ask. Or you can email me direct on [email protected]
Regards Al