Dr.Jekyll PHD

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Old 09-17-2018, 10:57 AM
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Mark 5
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Does anyone know the CG and control throws of this old bird? I have all the equipment and engine(DLE 20ra) installed and it seems to be very tail heavy. Also, what should this aircraft weigh? Mine is 10lbs.
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Old 09-20-2018, 03:58 AM
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Hi Mark,
Since nobody has responded I'll give you my 2 cents worth. First, I have never owned that particular pattern ship; so advice is based on other experience.
10lbs is a very reasonable weight for that airplane, especially with a gas engine installed. Typically, the C/G is right around the wing tube adjusted for flight performance and personal preference. Are the servos in the tail? It is better to add some weight to the nose for the sake of caution, for the first flights, then remove as necessary. As for control throws, when in doubt use your dual rates with about +/- 3/8" for the elevator and ailerons on high rate and maybe 2/3s of that for low rates.
Good luck!
-Will
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Old 09-20-2018, 09:43 AM
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Mark 5
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thanks for the advice Will. If the plane is balanced at that spot it will require about 10oz or more of led in the nose. That is the reason why I am trying to find the correct CG.
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Old 09-21-2018, 04:00 AM
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Hi Mark,
You might try contacting Leo here: https://www.rcmissouri.com/ballistic-aircraft-co.html
I believe he has the molds and plans for several (if not all) of the Jeckyll variants.
-Will
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Old 09-21-2018, 11:32 AM
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thanks, I will give Leo a call.
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Old 09-23-2018, 11:46 AM
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That plane balances on the tube/rear of tube or 27% MAC.
Somethings gone way wrong if you're needin' nose weight with a gasser.
Put servos in the rear? classed the rudder and stab?
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Old 09-23-2018, 06:00 PM
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Hi David, thanks for the help. I was told that the CG was in front of the tube, however if it is at the back of the tube, it will require less weight to balance. I don't know why this plane needs so much weight up front to balance. It was originally Chip Hyde's airplane, so I think it was built very good.
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Old 09-24-2018, 09:09 AM
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Then, very likey it's well built.
Just so you know, these aircraft aren't that GC sensitive.
I've had my old Hydeout 1 inch rear of the tube, would actually climb when inverted.... awfull for pattern, but still very easily flyable.
I spoke to Chip about his CG preference in those days and he said he set it in the following manner:
45 deg upline, roll inverted, hands off and adjust the CG to make the aircraft start carving a nice clean radius.
No voodoo​​​​​...​​Nice and simple.

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Old 09-25-2018, 05:48 AM
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Thanks Dave, if I can balance the airplane at the very rear of the spar it would require very little led up front.
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Old 09-25-2018, 05:59 AM
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Hi Mark,
I don't know what Chip had in it for power originally (not a DLE 20RA), probably a YS 120AC or SC or an OS 120SP or a version of the YS 1.40. Any of those 4-strokes with exhaust system weigh as much or more than the DLE 20; so adding a few ounces of nose weight seems reasonable.
-Will
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Old 09-25-2018, 09:05 AM
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Originally Posted by Mark 5 View Post
Thanks Dave, if I can balance the airplane at the very rear of the spar it would require very little led up front.
NICE! And do that CG trick to fine tune the CG. A nice long 45deg up, roll inverted-hands off and watch for a nice curve to start forming. Be prepared to added a little extra up front to move the CG forward and help carve the curve if required. I guess you'll be very close at the rear of the tube. Just to be on the safe side, dial in a couple of alternative elevator rates on a spare switch, that way if you're miles of the mark, you'll have a throw setting that function good enough to get home without any drama. Enjoy.

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Old 09-25-2018, 10:00 AM
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Thanks for all the help Will and David. I am going to balance the airplane at the rear of the wing tube and let you know how it flies. It may take a week or more to fly because of the rain, flooding and visit of the president(playing golf).
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Old 10-04-2018, 05:15 AM
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I got 4 flights on the Dr. Jekyll. What a great flying airplane. The DLE20RA pulls it around nicely. David, I tried your suggestion on finding the CG and it now seems to be a little nose heavy, so I will begin to remove some weight up front and will be looking into installing a tuned pipe.
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