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Jan 01, 2006, 10:22 AM
High Altitude Flyer
viking60's Avatar

EPP Beagle Squadron over South Park


Gene,

I have to confess that after over 20 years of scratch building and designing aircraft, I'm more than a bit irreverent about other people's plans; designing for flying at 10,000 feet does add it's own considerations. I really liked the Beagle, and also liked the idea of using EPP & CF for maximum durability... and I not only enlarged the wing area, but then enlarged the tail group and stretched the tail moment to give it good stability.

So as you noted, mine is an 'adaptation' of your inspirational design, and I thank you for the fine inspiration!

Winds were finally down by the afternoon of New Year's Eve Day, and after we had gathered with some good friends and feasted on a Turkey with all of the trimmings, three of us headed down the road a couple miles to some 'wide open spaces' - large hay meadows- to finally fly the EPP Beagle.

I had built two wings, both with a 33" span x 7" chord; the first was built with the 4%/40% undercambered airfoil and a 16" flat center panel with 8-1/2" raised tip panels. The second wing was built with a 8.8%/40% undercambered airfoil with a 15" center panel and 9" tip panels. (There is about 2-9/16" rise at the leading edge of the tip panels from the polyhedral joints, with only 1/16" washout at the outboard panel trailing edges.)

The power system is a GWS LPS RXC, which has a 7.2 volt motor and 5.0:1 gearing, running on a 2 cell 1300 mAH LiPo, swinging a 9x7 GWS prop in our thin air ; (a 9x4.7 is the recommended optimum sea level prop for this motor/ battery combo.)

Winds were variable, with our typical winter mid-afternoon 'cold thermals' with turbulent air marching through fairly regularly, with winds down to almost nothing in between. Time for this Beagle to FLY!

I mounted the 4% camber wing first, and it flew well, despite the variable winds. Both of my flying buddies had not been out flying in quite a while - (Phil confessed that it had been close to three years since he last flew!), but they did well when I handed them the transmitter.

With the modest power system, this Beagle definitely flies on the wing- and does it very well! It can hover and fly backwards at low throttle settings when the winds come up, but has enough authority at full throttle to fly back upwind in 15MPH+ winds when some of the turbulent winds would cycle through... (we were flying with the sun & wind at our backs most of the time.)

The higher camber wing went on next, and it quickly became obvious that this wing was more stable with less 'wing rocking' in the hands of my friends, and could be flown at modest throttle settings in low & close. At full throtle, it would still penetrate the winds when they cycled up stronger & more turbulent, but I could get more irreverent in my low & slow flying, doing very slow landings right at our feet. (Jim should have some good in-flight close-in photos... no video has been shot so far, but that may happen at the SPARCS Winter Fly-in on the 22nd.)

We flew out most of two battery packs, ended up with heavy grins, and headed back to the shop for some construction work. These guys were confirmed Beagle fans by that time!

(The ladies were watching the football game, while we were flying & then building- how's that for ignoring the typical role stereotypes!)

Before they left later that evening, two more EPP Beagles were completely built up, ready for the gear when it arrives!
That's about the quickest project I've ever worked with friends to complete; thanks to EPP, BlueCor, Hot Melt Glue & 5 minute epoxy, it's definitely possible!

The South Park Beagle Squadron is growing!!!
Last edited by viking60; Jan 01, 2006 at 10:52 AM.
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Jan 01, 2006, 01:43 PM
Curiouser and curiouser
Kokopeli's Avatar
Gene:
Do you know how heavy that 1/4 and 3/16" spruce is?
I have some alum. tube arrow shafts that are about 1/2 oz. for 22".
I might try to use that if I can figure out how to get a way to fasten it firmly so that the tail doesn't rotate. I think I can do that with tiny pop rivets.
But if spruce is lighter I will search for spruce.
Thanks
Jan 01, 2006, 05:44 PM
Crash Master
Gene Bond's Avatar
Thread OP
vil: Great story! I love it. Tell the guys I wish them well, and am glad we could help bring a little joy their way!

Great adaptation, again. The higher chamber wing should be stronger as well. I haven't really spent too much time trying a bunch of different ones, but I do know the 4% works much better than the 15% or so we've tried on others. I wonder if the thin air affects that parameter as well?

wj: 3/16" spruce = 2.66g/ft, 1/4" spruce = 5g/ft, c/f arrow shaft I tried = 6.5g/ft, 3/16" c/f tube I tried = 5g/ft... Your shaft would be ~ 7.6g/ft
Jan 01, 2006, 07:08 PM
High Altitude Flyer
viking60's Avatar

Camber at high altitude: EPP Beagle gets the art work


Gene,

I expect there's some effect of the ~16% thinner air on the lift of the flat plate undercambered airfoils, but I can not yet say how much; I'll probably do a new ~6%/ 40% wing soon, & look for a good low / no wind day to compare all three wings. The 8+ % camber is flying nicely & handles very well when slowed way down, so that wing / % camber will see a lot of service.

Today was a good day to get on the art work on the EPP; the photos below show the results of my modest efforts using Sharpie and Pantone permanent markers directly on the EPP.

Weight of the EPP fuselage with tail boom and motor mount shaft of .157" C.F. tube hot-melt glued in place is 26 grams after the art work, before any component placement or taping, etc.

Bruce
Last edited by viking60; Jan 01, 2006 at 07:17 PM.
Jan 01, 2006, 08:11 PM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
Well , that's certainly a thorough evaluation ....and SPBS to boot !!!! WAY COOL !!!!

Gene , Glad you're back !!!... Got a question ...hahahaha... I know this sounds silly , but you said "most all pushers fight tail weight problems"... Howz' about a little sweep back in the wing ??? moves the cg aft , gives a dihedral effect , and looks cool .... ??? Eh , Mon ???
Latest blog entry: Lost plans
Jan 01, 2006, 09:06 PM
Curiouser and curiouser
Kokopeli's Avatar
Quote:
Originally Posted by Gene Bond
wj: 3/16" spruce = 2.66g/ft, 1/4" spruce = 5g/ft, c/f arrow shaft I tried = 6.5g/ft, 3/16" c/f tube I tried = 5g/ft... Your shaft would be ~ 7.6g/ft
Ha! I should have know that you would have already picked the lightest stuff available. Now I gotta go get my chain saw and my snow shoes out and look for a spruce tree.

Thanks, again Gene
Walt
Last edited by Kokopeli; Jan 01, 2006 at 09:16 PM. Reason: heck, I forgot to say thanks :(
Jan 01, 2006, 10:44 PM
Crash Master
Gene Bond's Avatar
Thread OP
Yup, sweep helps. So does the notch in the wing I just didn't want to sweep it since it makes it that much harder to build. My plan was to make a longer chord if needed, but it was fine with the relatively short tail I decided on...

No Problem, Mon (unlike the vacation! nothing except the flight home was the way it was scheduled... quite an adventure!)
Jan 02, 2006, 12:09 AM
Dismembered Member...
arx_n_sparx's Avatar
Quote:
Originally Posted by wjbite
Ha! I should have know that you would have already picked the lightest stuff available. Now I gotta go get my chain saw and my snow shoes out and look for a spruce tree.

Thanks, again Gene
Walt
What's wrong with the one dropping all of those needles in your living room ? You know, the one with all of them fancy decorations on it.....

Brad
Jan 02, 2006, 07:38 AM
gpw
gpw
“There’s no place like Foam”
gpw's Avatar
Would you guys like to know how to make a simple tapered boom ??? Got my EPP now , a large "cooking" chopstick ...NEW Beagle on the way ...
Latest blog entry: Lost plans
Jan 02, 2006, 08:29 AM
Registered User
Bruce-
Stop this nonsense. Your a grown man with a highly technical mind. Your acting like a child having fun. Oh- I forgot, what's wrong with that! Congrats and I can't wait until I see it fly.
Jan 02, 2006, 09:23 AM
High Altitude Flyer
viking60's Avatar

No such thing as too much fun


Ron,

Having FUN is what designing & flying RC planes is all about! (Helping others be successful at it is also well worth doing!)

I'm off to the shop to put together a 6% camber wing, then out to the hay meadows to fly them to compare the three wings.

Bruce
Jan 02, 2006, 10:22 AM
Curiouser and curiouser
Kokopeli's Avatar
Quote:
Originally Posted by Gene Bond
Yup, sweep helps. So does the notch in the wing I just didn't want to sweep it since it makes it that much harder to build. My plan was to make a longer chord if needed, but it was fine with the relatively short tail I decided on...
How about moving the notch forward, converting it to a hole/slot in the wing wide enough to allow an 8" prop to swing? If that gives relief from tail weight then it might be easier to add ailerons because they would now be in the prop wash from the mid-position pusher? OK, so you have already thought of that - why won't it work?
And back to the spruce thing - I had completely forgotten about that guy, Howard Hughes.
Jan 02, 2006, 11:45 AM
I make ARFs out of RTFs..
This is the wing that worked well for my son's "Commander Sirius Beagle":
Jan 02, 2006, 03:21 PM
Curiouser and curiouser
Kokopeli's Avatar
That looks interesting.
Is that wing basically the same dimentions with that notch cut out?
If not could you give me the measurements, please.
What I was thinking of would be the same cutout as yours but moved further forward so that there would be some wing surface behind the prop.
Jan 02, 2006, 08:08 PM
High Altitude Flyer
viking60's Avatar

EPP Beagle


Yesterday I completed the graphics on EPP Beagle #1. This morning I built a new wing & painted it as well as the tail group. This afternoon the winds let up enough to get out to fly it some more, using the newer 6% camber wing. Here's a couple of photos of it in the air, in low & close.

Winds were still gusty & strong enough to preclude being able to do the comparison flying of the 3 different cambers on all three wings. Hopefully we will have a quieter spell soon, wind-wise, to allow this evaluation to be completed.

For the growing "South Park Beagle Squadron's Photo Gallery", you can go to: http://www.stenulson.net/rcflight/beagle.htm

More photos and specifications, a power system parts & sources list, as well as more EPP build technique info will be added to that page as time allows; for now, the photos are online.

Bruce
Last edited by viking60; Jan 04, 2006 at 12:15 AM.


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