"1/2 A" & "1/8 A" airplanes These are the small ones...more popular now than ever.

Sharkface plan questions

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Old 05-29-2013, 08:26 AM
  #1
VUgearhead
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Default Sharkface plan questions



I downloaded the Sharkface plans as a tileprint and imported it into CAD to convert to a CAD drawing. My hope was to make it easier to produce printwood or plans for a laser mini-kit.

Anyway, there were some issues in the tileprint that I can't figure out. So here are my questions.

The wing design showed the ribs extending past the front of the trailing edge in plan view, but not in it's cross-section. What's happening here?

Also, the plan did not indicate the wood thickness to use for the fuse sides. I see 1/16" for top/bottom sheeting, 3/16" for wing saddle stiffeners, and 1/4" for nose doublers. So, what should I use for the actual fuse side?

The F1 using 1/2" balsa block seems kinda crazy, unless the plane needs that much weight up front to balance. Do most of you just extend the fuse sides and nose doublers up to the firewall instead of carving a 1/2" block?

For you reedie pylon racers out there, what control surfaces were you designing, rudder-elevator or aileron-elevator (or all 3)? Where did you find the best placement of gear to balance the plane?



Since I'm new to performance 1/2A, I was also considering enlarging the plan to a 36" wingspan to tame it down some. I'd be happy to share the CAD file for both the standard version and the enlarged on if Ican get these questions answered.

Thanks,

VUGearhead

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Old 05-29-2013, 02:04 PM
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Default RE: Sharkface plan questions

Quote:
ORIGINAL: VUgearhead

The wing design showed the ribs extending past the front of the trailing edge in plan view, but not in it's cross-section. What's happening here?

The cross-section just has the hidden line for the end of the rib missing. On a wing of this size, butting the rib against the TE with good joinery would be sufficient.

Also, the plan did not indicate the wood thickness to use for the fuse sides. I see 1/16'' for top/bottom sheeting, 3/16'' for wing saddle stiffeners, and 1/4'' for nose doublers. So, what should I use for the actual fuse side?

My inclination would be to use 3/32" for the sides and all doublers. Planes designed during this time frame were way overbuilt. Build to fly, not to crash.

The F1 using 1/2'' balsa block seems kinda crazy, unless the plane needs that much weight up front to balance. Do most of you just extend the fuse sides and nose doublers up to the firewall instead of carving a 1/2'' block?

Drop all the blocks and just extend the doublers

For you reedie pylon racers out there, what control surfaces were you designing, rudder-elevator or aileron-elevator (or all 3)?

This is a small plane - A/E will give you all you want.

Since I'm new to performance 1/2A, I was also considering enlarging the plan to a 36'' wingspan to tame it down some. I'd be happy to share the CAD file for both the standard version and the enlarged on if I can get these questions answered.

You might consider 30" to 32" rather than 36", particularly if you're going with a COX reedie.
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Old 05-29-2013, 04:24 PM
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Default RE: Sharkface plan questions

I concur with Andrew on A/E. It's all you need.
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Old 05-29-2013, 05:51 PM
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Default RE: Sharkface plan questions

Thanks guys,

So, for A/E do you use full length ailerons? Also, do you reduce or eliminate the dihedral on the wing?


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Old 05-30-2013, 03:27 AM
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Default RE: Sharkface plan questions

I would have to go back and look at RR event pics if they are still available but I think Hollis made his with a little less DH.
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Old 05-30-2013, 07:58 AM
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Default RE: Sharkface plan questions

You can simplify further and just put an aileron on the left wing.
I know it offends ones sense of symmetry, but it works OK from what I hear.
(That's right, I have never tried it myself, but I have never built anything
for 1/2a faster than a Noel Rozelle "Hornet" (RCM plan #705 Oct-1977)
Dave
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Old 05-30-2013, 08:35 AM
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Default RE: Sharkface plan questions

Quote:
ORIGINAL: fritzke

You can simplify further and just put an aileron on the left wing.
I know it offends ones sense of symmetry, but it works OK from what I hear.
Dave
Dave -

I think CombatPigg has tried one aileron vs two and was not impressed. If you're only pylon racing in a left-hand pattern, there might be some speed advantage, but in you're in a hard left turn with the left wing down, any aileron input would tend to pull the nose down, unless you have rudder.

I have the Hornet plans, but have not built one - with that thin wing, it should have been pretty quick.
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Old 05-30-2013, 09:09 AM
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Default RE: Sharkface plan questions

I've done quite a few 1/2A racing planes with 1 aileron only.
If you are looking for pretty, axial rolls, forget it. But, if
you are only interested in speed and making left turns only,
it works great.
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Old 05-30-2013, 09:29 AM
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Default RE: Sharkface plan questions

I have tried one aileron on two 1/2a planes (for racing) and HATED LIFE. [:'(]
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Old 05-30-2013, 12:17 PM
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Default RE: Sharkface plan questions

I am slightly intrigued by the discussion-the 'Sharkface' I am familiar with was a very small (and fast) single channel design by Eric Clutton, published as a free fullsize pull out plan in Aeromodeller in 1965. The attached pics of the model and drawing are from 'outerzone'-are we talking about the same model design? Or another model completely?

ChrisM
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Old 05-30-2013, 12:53 PM
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Default RE: Sharkface plan questions

I hope you can make out some details in this picture.
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Old 05-30-2013, 12:58 PM
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Default RE: Sharkface plan questions

That's the same one I was thinking of-and a PAW55 is a good choice for power.............

ChrisM
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Old 05-30-2013, 01:20 PM
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Default RE: Sharkface plan questions

And the MAN comes to the conversation!
Hi Hollis
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Old 05-30-2013, 02:06 PM
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Default RE: Sharkface plan questions

Well, there you have it, for general sport flying, install 2 ailerons!
Dave
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Old 05-30-2013, 03:39 PM
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Default RE: Sharkface plan questions

Hi Vic, and all others as well. Mine was rudder, elevator, throttle (love that PAW 55 throttle!). I did groove the trailing edges for the ribs. I think the sides were 1/16" with some 3/32" or 1/8" sticks in the corners.
Edit, I was able to zoom in on my photo and read the balsa size (see the SIG emblem?) and the sides were 1/16".
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Old 05-30-2013, 03:57 PM
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Default RE: Sharkface plan questions

I did a big of digging on the net-and turned up the fact that the revised version appeared in the Feb 1989 issue of 'Radio Modeller'-the cover looked familiar, so I went digging in my own magazine archives-and sure enough I had the issue-still with the plan stapled in place. I can't find my original '65 Aeromodeller with the original, so can't say how much the revised version differs, but its certainly a small model-even if robustly built! The Gordon Counsell redesign version used a Frog 100 diesel-so I imagine it was fast! [and I shudder to think what the original must have been like with a 1.5 in it-as the designer claimed he'd used......] FWIW the David Boddington 'Tyro' trainer design-which was my first R/C model back in 1974-also showed a Frog 100 on the plan-but it was 45" span. In a 22" model.................!

The 89 revised plan shows 1/16" sheet sides.....the 1/2" noseblock is probably a hangover from the original-which used a 'knock-off' engine mount setup, and so needed a fairly solid backup [and largely used bigger and heavier diesels up front as compared to glows.] I also get the impression that with the original design, it was intended to be fast and hairy-and it was-so crashes were not infrequent and it was built to take a lot of punishment, so the structure is hefty for such a small model. With glow power you could probably lighten up a bit of the front end structure.............

ChrisM
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Old 06-04-2013, 06:35 AM
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Default RE: Sharkface plan questions

So, for those of you who built your Sharkface as A/E, can you provide the specs on the wing modifications?

What did you reduce the dihedral to, or did you eliminate it entirely?

For the aileron, how big did you make them? Full length or something less?

Sorry if I'm sounding a bit like a pest, but if I'm going to draw this up in CAD,Iwant to show it right.

BTW, Ialso plan on laying out printsfor the balsa sheets, so if anyone wants, they can take it to a plotter and get a toner copy to use for making print wood. The balsa sheetlayouts will also be in the CAD file with the pieces as polylines, for those of you partial to laser cutting.

Thanks
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