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07-13-2005, 08:41 PM | #1 |
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Tail Heavy/Sig Astro-Hog
Looking for some info and or opinions on balancing my astro-hog.
Some background info first. In building this model, I decided to fiberglass the fuse and sheet in the wing and glass it as well. Needless to say I have increased the overall weight from the recommended 7 - 7 1/2lbs. to about 8 1/2lbs. According to the plans the C.G. is approximately 3 1/2" behind the L.E. although the main spar is almost 4" behind the L.E. Using the recommended C.G. the plane is quite tale heavy and I will need to add approximately 12 to 14oz of weight to the front of the fuse to balance. I'm using a K&B 65 for power, a Higley Heavy Hub for a spinner and I have the receiver moved as far forward as possible. Is adding this amount of weight acceptable : It will increase the overall weight to almost 10lbs Any ideas as to what the flying/stall characteristics might be like : : I would appreciate any help or other suggestions out there. Thanks Kip |
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07-13-2005, 09:01 PM | #2 |
RCC Contributor
I am: grant
Join Date: Dec 2003
Location: churchbridge, sask
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Hi kip, I think the old saying is an ounce in the tail = a pound in the nose.
I am not familliar with the plane, and the factory CG is prob pretty close, but if ur approaching the 10 pound mark, ur prob gettin a bit too heavy. Would be more benificial if you can add some lighting holes in the tail section some place, to the tune of about an ounce or so. I had to add tail weight to my recent project, a staudaucher S-300, because of the engine I used. I managed to reduce the amount added, after drilling lightening holes into the front plywood, by a couple of ounces. Thats about all I can tell you, and hopefully, anybody with a bit more experience with the plane can give you some better info. Good luck SJ
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happy flying |
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07-13-2005, 10:13 PM | #3 |
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I am: Ted L
Join Date: May 2004
Location: Puslinch, ON, Canada
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In my experience dead weight in the nose is always a bad thing. By dead weight I mean weight that does nothing for you except balance the plane. Perhaps going to a larger motor or a four stroke motor will give you the proper center of gravity. As far as lightening up the tail of the plane it is going to be alot of work. It does not take much weight from the tail to make a difference some times but if the whole thing is fiberglassed then its not going to be easy. This may turn out to be one of those lessons where you learn how to not build an aircraft. Not to say you shouldn't have built it the way you did but perhaps there were areas that you could have lightened up if you built it from the start knowing you were going to fiberglass it. I am curious why you decided to fiberglass this model as it has been flying since the fifties in its current design and I have never heard of someone saying it was a weak airframe.
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Ted LeBlanc |
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07-14-2005, 08:00 AM | #4 |
RCC Junior Contributor
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Astro Hog
I had an Astro Hog and it flew great with a OS 61 4 stroke 12x6 prop but it was built lite as the plans called for. The balance was a bit nose heavy. I would put a 90 4 stroke in there should be enough room in the nose for it This should add the weigh and power to fly this plane. A tail heavy plane is asking for trouble such as stalls and touchy controls. Hope this helps.
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Wise Guy Sun Parlor R/C club Windsor Ont |
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07-14-2005, 12:24 PM | #5 |
RCC Junior Contributor
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Unfortunately, about 70% of the weight you added to the fuselage is behind the desired CG. An overweight plane is a bad thing, but a tail heavy plane is worse. You really only have 2 options, either add the weight to the nose, whether it be lead or a larger engine, or you can lighten the tail by cutting lightening holes and covering them.
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1/2A all the way! |
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07-17-2005, 08:40 PM | #6 |
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Tail Heavy/Sig Astro-Hog
Thanks for your help guys.
When I balanced this plane, needless to say I was really disappointed that she was so tail-heavy. Having bought the kit approx 16-17 years ago( I've been out of the hobby for a while)......I wasn't sure what I was going to do!!!!!!! RC Canada to the rescue. I flew her maiden voyage this evening at our field with much success. The take-off was almost scale. The tail wheel came up @ about 1/2 throttle as I slowly increased speed and rotated skyward. When I figured I had enough altitude I made an slow left and leveled her up. Slight trim corrections on the ailerons, rudder & elevator and @ 1/2 throttle she was flying great. No problem on the landing either. Now here is what was needed to correct the problem and balance the plane. I cut 8- 1 1/4" lightening holes in the elevator, another 2 in the stab and 3 more in the rudder. I covered these with trim sheets. I put a 1/2" spacer between the motor-mount and the firewall driving the engine forward, and went from the K & B 65 to a Thunder-Tiger 61GP which was 1/2lb heavier. In the end I only had to add about 6oz of lead weight to balance the plane. Her overall weight is exactly 10lbs. So she is about 2.5lbs heavier than she should be but hay.............SHE FLIES Thanks again guys for your help and ideas. In my books RC Canada Rocks Here is a photo just before take-off. |
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07-17-2005, 08:43 PM | #7 |
Guest
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Tail Heavy/Sig Astro-Hog
Thanks for your help guys.
When I balanced this plane, needless to say I was really disappointed that she was so tail-heavy. Having bought the kit approx 16-17 years ago( I've been out of the hobby for a while)......I wasn't sure what I was going to do!!!!!!! RC Canada to the rescue. I flew her maiden voyage this evening at our field with much success. The take-off was almost scale. The tail wheel came up @ about 1/2 throttle as I slowly increased speed and rotated skyward. When I figured I had enough altitude I made an slow left and leveled her up. Slight trim corrections on the ailerons, rudder & elevator and @ 1/2 throttle she was flying great. No problem on the landing either. Now here is what was needed to correct the problem and balance the plane. I cut 8- 1 1/4" lightening holes in the elevator, another 2 in the stab and 3 more in the rudder. I covered these with trim sheets. I put a 1/2" spacer between the motor-mount and the firewall driving the engine forward, and went from the K & B 65 to a Thunder-Tiger 61GP which was 1/2lb heavier. In the end I only had to add about 6oz of lead weight to balance the plane. Her overall weight is exactly 10lbs. So she is about 2.5lbs heavier than she should be but hay.............SHE FLIES Thanks again guys for your help and ideas. In my books RC Canada Rocks Here is a photo just before take-off. |
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