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Design => Stunt design => Topic started by: Brian Massey on June 14, 2017, 02:35:37 PM

Title: Changing My Favorite Plane
Post by: Brian Massey on June 14, 2017, 02:35:37 PM
I've been a fan of Tom Warden's Trophy Trainer since my Whittier Narrows days way back when. To date I've built a half dozen or so. But since getting back into C/L a few years back, I've wanted to try a few changes. Since I have no background in engineering, or design, I'm here.

Here's some of the changes I'm considering:

1/ I want to give the wing some sweep, probably by increasing the chord of the wing at the fuse by 1/2 to 3/4 inch.

2/ Increase the area of the stab & elevator to more modern numbers.

Question: While increasing the chord of the center rib(s), would there be in benefit or negative issues raised by also proportionally increasing the thickness of the rib, and tapering to the original thickness at the tip?

As for the tail surfaces, I've read DF's article on "Details" and will probably go with what his research showed worked best.


Am I stupid for wanting to mess with a proven good design?

Thanks for any advice/input you feel worthwhile for me to consider.

Brian
Title: Re: Changing My Favorite Plane
Post by: Tim Wescott on June 14, 2017, 04:46:21 PM
First, just to get it out of the way: we're all stupid for not taking up golf.  So it doesn't matter whether what you're trying to do is "stupid" in someone else's eyes -- if you like it, go for it.

Second, if you want the performance of a modern stunter with the looks of a Trophy Trainer, I suggest that you find a good high-performance profile (I can't suggest one -- ask), and modify the fuselage profile, rudder, and tail shape to match, while maintaining the same tail area.  That should get you close.
Title: Re: Changing My Favorite Plane
Post by: Brett Buck on June 14, 2017, 06:30:59 PM
First, just to get it out of the way: we're all stupid for not taking up golf.  So it doesn't matter whether what you're trying to do is "stupid" in someone else's eyes -- if you like it, go for it.

Second, if you want the performance of a modern stunter with the looks of a Trophy Trainer, I suggest that you find a good high-performance profile (I can't suggest one -- ask), and modify the fuselage profile, rudder, and tail shape to match, while maintaining the same tail area.  That should get you close.

   The Prowler seems to fit the bill, for example.

     Brett
Title: Re: Changing My Favorite Plane
Post by: Dave_Trible on June 15, 2017, 07:24:30 PM
I've been a fan of Tom Warden's Trophy Trainer since my Whittier Narrows days way back when. To date I've built a half dozen or so. But since getting back into C/L a few years back, I've wanted to try a few changes. Since I have no background in engineering, or design, I'm here.

Here's some of the changes I'm considering:

1/ I want to give the wing some sweep, probably by increasing the chord of the wing at the fuse by 1/2 to 3/4 inch.

2/ Increase the area of the stab & elevator to more modern numbers.

Question: While increasing the chord of the center rib(s), would there be in benefit or negative issues raised by also proportionally increasing the thickness of the rib, and tapering to the original thickness at the tip?

As for the tail surfaces, I've read DF's article on "Details" and will probably go with what his research showed worked best.


Am I stupid for wanting to mess with a proven good design?

Thanks for any advice/input you feel worthwhile for me to consider.

Brian

Brian I am totally unfamiliar with this design but if I were going to do what you are thinking I would take the existing root rib and photo-enlarge it to whatever chord you wish.  It will proportionately maintain the design airfoil at the root, but still create an altogether different(likely better) wing.  If it uses flaps increase them the same proportion.  If the originals used lighter weight engines and you are now going to use a modern - read that heavier- powerplant this wing should be more able to lift it but you might also want to look at pushing the stab back some to maintain a good CG and gain leverage.  A larger stab/elevator will permit a more rearward CG.  Whether it will fly like the original? Doubtful but likely better.

Dave
Title: Re: Changing My Favorite Plane
Post by: Walter Hicks on June 25, 2017, 07:10:20 PM
Brian Just Build an Imitation far better airplane with no mods needed!!!!!! :)