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Old Oct 02, 2010, 10:30 AM
Chino Renegade oh-gee, yo
Wrench66's Avatar
United States, CA, Chino
Joined Feb 2008
2,549 Posts
Build Log
New build of old design, low wing sports model

Hi all,
I always liked the sleek, speedy looking sport low wing planes from back in the 60's and 70's so I decided to build something along that type but with a twist......incorporate a twin rudder design and operate a tailwheel with them all off of a single servo. So I set off with some pencil drawings and some markers to sketch out what I thought I wanted. Couldn't find much on the subject but that didn't bother me I just wanted to be different.
I did do the entire tail assy as removeable though in case 1) it doesn't fly like the one in my mind's eye....LOL and 2) so I could switch to a std vertical stab/rudder and H stab if needed without having to redo the entire project's fuse.
The wing is made form a pair of pink foam cores I was given sometime ago by Mike @ Air Capitol Hobbies of OK., approx 240in of area and a nice semi sym airfoil. The fuse is a mixture of 6mm Depron and a section of 1.75in blue foam material cut to make a MonoBlock assy. This type of material is what use to help create a straight and strong box fuse.....the MB foam is used for the wingsaddle, battery compartment floor and the firewall/motormount areas. Both of my Edge 540 and Mini Kaos aka TLAR 400 scratchbuilds incorporate the same type of build Another note is that all of the color for the plane will be either colored packing tape or acrylic craft paints....I've yet to learn the art of covering...hahaha....coming soon though I'm sure.
OK, some specs:

WS 37"
length 36"
wing area 240" Wing loading 13 - 14oz sqft
projected AUW 20+
Power 180W - 200W

Hope you like the build up

--Ray
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Old Oct 02, 2010, 10:56 AM
Chino Renegade oh-gee, yo
Wrench66's Avatar
United States, CA, Chino
Joined Feb 2008
2,549 Posts
More please

A few more shots of the fuse......simple, fairly stout and fun to do The sequence I use is to build my wing halves first, use the outline of the airfoil and trace to the plan sheet (all the while keeping an eye on not including any incidence between the wing and fuse). Then with the correct wing shape drawn I can then cutout my fuselage sides and the center blu foam block The tail assy slots come next, on this particular plane I made it even easier by utilising the top of the fuse as the horiz stab's "perch"...keeping the angles all in check
I was not sure of the vertical stab's (x2 remember) size requirements, so I took some rough measurements of a single vertical and made both of my twin sections add up to nearly the same area......sooooo should be OK? Hoping so, won't really know until it's up and away..hahaha....boy do I hate variables in a science project like this!

--Ray
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Old Oct 03, 2010, 07:05 PM
Build straight - Fly twisty
Whiskers's Avatar
Australia, QLD, Little Mountain
Joined Feb 2010
4,212 Posts
Should be good!
I use 200 W motors in planes about that size and weight, and I love 'em.
I'd make the ailerons way bigger than you have in your sketch. But that's just me...
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Old Oct 07, 2010, 10:18 AM
Chino Renegade oh-gee, yo
Wrench66's Avatar
United States, CA, Chino
Joined Feb 2008
2,549 Posts
Yeah, I agree Whiskers that 200W sounds like a nice even target to use I do realize that the trend these days is to have an overabundence of deflection area in all the control surfaces, but for this build I think I am trying to stay on the conservative side of things since this plane was designed to emulate the sport planes from earlier days before the big 3D push.......we'll see how we end up
Working through the design of the single control rudder and tailwheel had me scratching my head at first.....the easy way would have been to use two servos OR one servo positioned way back at the end of the fuse. Becuase this plane has a little longer fuse moment for better stability I have been critical of anything other than what's absolutely nessasary be stuck behind the wing...LOL. I did end up using a Dubro .40 size tail wheel mount and a couple homemade bellcrank pieces to come away with a working item. The only consolation is that the right rudder fin has a skoash less total movement than it's sibling.....caused by the way the control wires are actuated. Shouldn't be much of a prob hopefully
I went ahead and made my own control horns from a cut up gift card (procured from the local Wally World) and lite ply, bent up the wire and found a couple unused connectors from a GWS platic tree.....then hooked everything up and checked all the workings. Everything is working smoothly, yay! haha. I had decided to do a blue-white with orange pinstripe color scheme so I went ahead and taped up the tail before going further.
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Old Oct 07, 2010, 10:27 AM
Chino Renegade oh-gee, yo
Wrench66's Avatar
United States, CA, Chino
Joined Feb 2008
2,549 Posts
I took the wing cores and prepped them to be glued together. I wanted a few degrees of dihedral to keep the wing from looking "droopy" in flight (sometimes a dead flat wing will seem like it has a droop), so I sanded the mating surfaces to include approx 4 degrees of dihedral.....just enough to be called bent..LOL. I incorporated a 3mm carbon spar to keep any flex to a minimum and placed it near where CG should end up being.
Now I drilled a couple small holes in the fuse sides to slide in the bamboo dowels and gave them a nice coating of epoxy as they were placed home. These are the tabs for the wing rubberbands.
As I was mounting the wing to get an idea how everything would be fitting I noticed my wing to fuse to tail incidence had gotten off just a little, a little extra work with the sand paper and bubble levels got everything back into line fairly quickly I cut the pockets for my servos and glued in the wooden bars to screw the servos on to. I used to just hot glue the servos in but have since discovered I like this way much better. I ran the control wires down the fuse and out to the tail, using nylon wire guides thoughout.
Looking a little bit further I wanted to get a first impression of where my balance was heading for.......so I stuck a motor on the front that I thought I would wanna use and threw all the other electronic bits in the fuse cavity where I thought they might end up. First look showed the plane a little nose heavy with a 2200mah 3s up front behind the firewall...so as I slid the battery rearward towards the LE of the wing things began to lighten up and come into balance. Great! I always worry about the CG thing during a build up....LOL. The smaller batteries I might wanna use showed that the plane would be happy with them a little forward of the 2200 of course, I also have a choice of using a slightly lighter motor in combo with any of the batteries (1000mah to 2200mah 3s) and balance the plane so that's good. I always like to leave as much room in the battery compartment to move things around if needed and using a lite ply battery compartment floor I can use Velcro to stick the battery where ever is good
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Old Oct 07, 2010, 04:42 PM
Build straight - Fly twisty
Whiskers's Avatar
Australia, QLD, Little Mountain
Joined Feb 2010
4,212 Posts
Well nobody will be able to say the tail-wheel is under size
Those ailerons will do the job just fine, being larger than I thought they would be judging from your sketch. (but I'd have 'em much bigger )
I must say I'm not a big fan of rubber banded wings but I guess they are appropriate for the 'feel' of this model.
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Old Oct 07, 2010, 08:33 PM
Chino Renegade oh-gee, yo
Wrench66's Avatar
United States, CA, Chino
Joined Feb 2008
2,549 Posts
I think the photo makes the tailwheel look larger than it is, but since I do most of my flying off of a medium length grass field bigger wheels are a huge help.
Continuing with the wing, I drew out a few different color stripes and combos and came up with a style a lot like I saw in a magazine a ong time ago. You can see the canopy I have decided to use, it's from an F-16 that just got retired last week.....it fits pretty much the theme I am going for too...LOL. Taping the wing and the fuse sides is a lot of fun, boy does it add a ton of strength to them too!! I am using a pair of lite ply plates and pins to locate the wing to the fuse, keep things from moving around too much

I'm happy with the way this is shaping up so far, hope it flies as well.

--Ray
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Old Oct 07, 2010, 09:40 PM
Build straight - Fly twisty
Whiskers's Avatar
Australia, QLD, Little Mountain
Joined Feb 2010
4,212 Posts
Flying from grass I usually don't bother with tail-wheels. We used to have a beautifully smooth grass field (until we were booted off) and I found ground handling was fine with just a fixed tail-skid. You need plenty of rudder authority.
Our new field is much rougher. Takeoff and landing are OK, but taxiing is not an option.
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Old Oct 07, 2010, 09:57 PM
Chino Renegade oh-gee, yo
Wrench66's Avatar
United States, CA, Chino
Joined Feb 2008
2,549 Posts
Yeah I have a few with the fixed rear wheel, full rudder and a good blast of throttle is usually enough to bring her around I was concerned though that the smaller rudders and the fact that they aren't in the prop's slipstream wouldn't allow much ground authority......ROG'ing usually needs a little or more right rudder to keep her straight down the runway, so the tailwheel is nessasary to counter the torque over hopefully until her tail comes up and airspeed will save it.
I am using a battery securing method that has worked well for me in a number of previous planes.....using a doctor's tongue depressor , velcro strips and digging out a shallow trough I use the hot glue gun again to seat the assy into the fuse. This makes a 100% improvement over mearly sticking the Velcro strips to the blue foam floor.
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Old Oct 07, 2010, 11:39 PM
Lawn dart pilot/builder
Prime_8's Avatar
N.L. Canada
Joined Jun 2010
2,337 Posts
love it , an di like how you did teh main block.

very cool.

i love long sporty planes too.

see my foam beast ...
all pink foam , including wing core i cut .
shampoo bottle for cowl and just a plastic stick for tail skid.
( i have huge rudder LOL , so no worries for taxi - see vids in my build log - )
covers in tape , chrome duck tape LE , starpping tape used as spars ,
and self sticking vinyl shelf covering for top covering of wing and fuss makes it very strong now .
my wing is held on by LE pins like yours , and a nybolt at TE of wing root

my PL build log
http://www.rcgroups.com/forums/showthread.php?t=1290343
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Old Oct 08, 2010, 07:51 AM
Build straight - Fly twisty
Whiskers's Avatar
Australia, QLD, Little Mountain
Joined Feb 2010
4,212 Posts
Quote: ROG'ing usually needs a little or more right rudder to keep her straight down the runway, so the tailwheel is nessasary to counter the torque over hopefully until her tail comes up and airspeed will save it.
When I hit mine with 200W they get off in about 24" and it's more straight up in the sky than straight down the runway.
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Old Mar 15, 2011, 09:21 PM
Grounded Pilot
IIIBonesAirForce's Avatar
USA, MN, Rochester
Joined Jul 2007
214 Posts
Nice job man keep on keeping on
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