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General control line discussion => Open Forum => Topic started by: RC Storick on September 14, 2013, 08:03:10 PM
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Went to the field yesterday and put up 4 3 minute flights with not much change. Its been 20 years sense I have had a airplane that really flew like they did way back when. So I keep chasing my tail to engineer the plane to fly like they did without much success until now. Viper 8 weighed 48 ounces at the NATS and it flew OK but not much change in the feel of the aircraft. That feeling has to do with concentrated weight at the farthest from the point of tether.
The first flights on E viper felt just like a piped plane and this is not what I am looking for. I didn't think that only 10 ounces would have the drastic effect that it did after moving it. Ron looked inside and said to me that the battery will end up inline with the wing and as far back as I could make it. After a few hours of re-engineering the mounting system I accomplished this. Took it out today with much joy! I ended taking out 1/2 of the 1/4 ounce of tip weight I had in it. It really doesn't need much with the asymmetry that's built in. 5.3 lap times and dead nuts line tension. This is due to motor offset. I moved the lines forward so that it didn't crab in and out of the wind. Its such a positive responding airplane there is hope.
It finished at 54.5 ounces and it doesn't matter what anyone says its all about weight. Now if I could just remove the battery.
If you come on here and say I'm wrong you just don't have a clue no matter who you are.
The next Evolution Viper
I have a good friend where we discuss design parameters on a daily basis. The next generation Viper will be slightly smaller somewhere around 630 SQ. This Viper has a 11.5 inch wing cord and this tends to make the fuse very long. It looks streamline and cool but it sets up a few things like long clock time. So the next one will be 10.5 and shorter nose and tail moments.
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Hi Robert,
I'm glad the Viper is working out to at least some of your important expectations.
I'm not sure that it's all about weight...there are obviously a lot of other things that have to work out also; IE, alignment, lack of flexibility, etc., etc., etc. But! I certainly do agree that weight is the most important factor in having a predictable responsive airplane.
I flew a 53 oz 720 sq in Geo XL for many years and it was definitely the easiest most predictable airplane I've had to date. It's not easy to build a big airplane that light but is definitely worth the effort.
Keep on Keep'n on!
Randy Cuberly
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What I mean by that is the base line characteristics are defined by the concentrated weight. IE the drive train.
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What I mean by that is the base line characteristics are defined by the concentrated weight. IE the drive train.
I agree. I think that's the primary reason that the electrics typically need very different trim parameters than typical IC airplanes.
Randy Cuberly
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Charged the batteries and went to the field today only to find the wind gusting to 20 MPH. So I watched the RC guys fly for a while. Came home and started massaging the paint on the Viper. Sanding and rubbing. Fixing all the bad spots. While the finish is not my normal like glass finish it is acceptable.
I had a few bad spots show up after clearing it. So I sanded them and dusted some paint on and it will probably take a few more sessions to get them all. This paint job is like chrome. Very thin but shiny.
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I'm a little confused, did you use a longer skinnier pack?
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I'm glad it's making you happy, Robert. That's the most important thing.
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Bob,
Hope to see it at Broken Arrow this weekend!
Steve
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Bob,
Hope to see it at Broken Arrow this weekend!
Steve
It will be there but I don't have enough time on it to fly it in the contest
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Well I had 10 flights on it and decided to fly it anyway. Scored a 539. Not too bad for a unfamiliar airplane. I am quite pleased. It is so much fun to fly I could not resist even un trimmed.
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What do you mean by "long clock time" on the longer fuselage? ???
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What do you mean by "long clock time" on the longer fuselage? ???
It takes longer to rotate.