HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jun 07, 2006, 09:44 PM
"SARGE"
sargentw's Avatar
Fairfax Station, (Northern) Virginia
Joined Jun 2003
3,150 Posts
The Great Planes Cog Machine

There seems to be alot of confusion about balancing the EZ. Another good topic for the build thread.

Update: 6/4/07 Additional Information about the CG Machine.
http://www.greatplanes.com/accys/gpmr2400.html

A COG Machine review:
http://www.greatplanes.com/reviews/gpmr2400-man.html

When I first started flying.... understanding the COG (center of gravity) balance point was difficult. Using fingers, forked sticks, and Grandma' crystal ball was not working. So I bought a great planes COG Machine and eliminated all the guesswork and started getting it right which helped eliminate crashes and other undesirable flying behavior.

Here is a picture of the Great Planes balance machine. They give you a little level which you can set on the wings above the balance point in case you have trouble seeing things "on the level".

The also give you little rulers that will help you pinpoint the balance point say 78 mm from the leading edge (if that's what the instructions told you to do)

I also have Lagenase' epoxy bumps put on my COG marks to make it easier to get an accurate COG balance check using the fingers at the flying field.
sargentw is offline Find More Posts by sargentw
Last edited by sargentw; Jun 04, 2007 at 08:39 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Jun 07, 2006, 11:53 PM
Fly by grace
rkhoo's Avatar
Canada
Joined Aug 2004
904 Posts
I used a smal plastic needle pin head to do the same. I think Epoxy is even simpler! Good tip.
rkhoo is offline Find More Posts by rkhoo
Reply With Quote
Old Jun 10, 2006, 08:12 AM
"SARGE"
sargentw's Avatar
Fairfax Station, (Northern) Virginia
Joined Jun 2003
3,150 Posts
The Folding Prop Mod

The folding prop mod. is nothing new. OldPilot and others have done this modification. My reasons for the mod are to reduce prop drag when soaring and now have one less set of sharp prop blades poking things when I throw the EZ in the back seat. I decided to go with a Sonictronic 6x4 folder after hearing reports like good performance, sturdy, and inexpensive. BTW: the yellow blades match the decals on the EZ.

You can get the props here.

http://sonictronics.com/xcart/home.php?cat=313

There was a question about my order and I received a follow-up phone call Sonictronics to clear it up. Man, good service wins me over everytime. The prop arrived in a couple days.

The nice thing about this prop is you don't have to mess with turning blades around and then mount a spinner. It's ready to go; just bore out the hole with a 5mm or 5/64 drill and make a small folding prop blade brake/stop and that's it.

I'll have the flight test/report in soon. Here are some pictures that detail the install

6/13/06 update: I tested the new prop with several WOT up/downs to 600 to 700 feet. This is a sturdy prop and there was no signs of stress or fatigue after the test. It folded back fine and popped open when hitting the throttle. I also did alot of low speed motoring around doing figure eights tight turns. All nice and smooth. This prop is a real keeper.

Update: 12/5/06 Check out the pics below and see what the wind sees in props upright rigid blades when flowing over the front of the EZ.

Update: 3/26/07 I like the Sonictronics folding props as pushers. I installed some on other sport planes, including a 7x4 on a EdgeRC Bird of Prey. Check out new picture below.

Update: 5/21/07 Here is a folding prop mod RandyK1 did for his Unicorn wing which uses a pusher type motor arrangement just like the EZ Star. This uses a Graupner 6x3 folder 3.2 mm motor shaft, and 30 mm spinner for that clean look. Randy's mod includes that "all important" blade stop.

http://www.rcgroups.com/forums/showt...&pagenumber=23
sargentw is offline Find More Posts by sargentw
Last edited by sargentw; Jun 22, 2008 at 08:50 AM.
Reply With Quote
Old Jun 10, 2006, 08:25 AM
Electricholics Anonymous
claybuster's Avatar
WARREN, MICHIGAN
Joined Jul 2005
1,959 Posts
Sarge,
Could you please comment on this?
I got my new Easy Star and would like comments on my setup. I will start out with a MPI Promax speed 400 7.2 reverse timed and with a flux ring installed.I will run a third wire through the fuse incase I go brushless later.I'm also using a CBP 7 cell 2/3a 1150 nimh, CC Pixie 20p speed control, two Hitec hs 81's, a Hitec electron 6 rx, this rx is 17g, is this to heavy? If I take the case off it will be 13g. Or should I use a lighter rx?I like the idea of having a full range rx,and I have a brand new one laying around. The only mods I think I will do are a rudder mod,canopy, and carbon fiber rod in the rear of the fuse. I will of course do all the tape requirements. I will also get a collet prop adaptor. Any ideas on which brand and size prop to use with this setup?I need all the help I can get with my first Easy Star. I also fly in a kinda small field but I'm looking for a larger one.I have some UHU glue left over from another build,will this be OK for gluing the fuse ? I also plan to Goop the motor in. Also should I run the carbon fiber rod the entire length of the rear of the fuse or just the last 6" ? I think I've seen it done both ways.
Mike
claybuster is offline Find More Posts by claybuster
Reply With Quote
Old Jun 10, 2006, 08:42 AM
"SARGE"
sargentw's Avatar
Fairfax Station, (Northern) Virginia
Joined Jun 2003
3,150 Posts
Quote:
Originally Posted by claybuster
Sarge,
Could you please comment on this?
I got my new Easy Star and would like comments on my setup. I will start out with a MPI Promax speed 400 7.2 reverse timed and with a flux ring installed (Fine).I will run a third wire through the fuse incase I go brushless later (Smart).I'm also using a CBP 7 cell 2/3a 1150 nimh, CC Pixie 20p speed control, two Hitec hs 81's, a Hitec electron 6 rx (Perfect), this rx is 17g, is this to heavy (No)? If I take the case off it will be 13g. Or should I use a lighter rx? (No) I like the idea of having a full range rx,and I have a brand new one laying around. The only mods I think I will do are a rudder mod,canopy (Good), and carbon fiber rod in the rear of the fuse (Helps). I will of course do all the tape requirements. I will also get a collet prop adaptor. Any ideas on which brand and size prop to use with this setup? (2.3mm M5-fits stock motor) I need all the help I can get with my first Easy Star. I also fly in a kinda small field but I'm looking for a larger one (If you are a new flyer find a larger one).I have some UHU glue left over from another build,will this be OK for gluing the fuse (glue it per instructions- remember if you can take apart you fuse it will fall apart in time too) ? I also plan to Goop the motor in (Excellent). Also should I run the carbon fiber rod the entire length of the rear of the fuse or just the last 6" ? (last 6") I think I've seen it done both ways.
Mike
Mike,

I think your plan sounds good to me. See my comments above in (xyz...) . I've noticed that others have answered some of the questions is the main EZ thread so you should drop them from your repeated post.

There is information in this thread about Collet adaptors and where to get them. Carbon fiber for the 6" is good-there is already a pre-made slot for it in the tail. Even though you can rush through this build, take each step one at a time and think about what you are doing. Also try and fit parts first before gluing; and again stop and think about what you are doing.

Good Luck!!
sargentw is offline Find More Posts by sargentw
Last edited by sargentw; Jun 10, 2006 at 09:22 AM.
Reply With Quote
Old Jun 10, 2006, 09:16 AM
Electricholics Anonymous
claybuster's Avatar
WARREN, MICHIGAN
Joined Jul 2005
1,959 Posts
Sarge,
Thanks for all the help! Now I can get started on the Easy Star and hopefully be flying it next weekend. Sorry for the repeated post, but I'm really anxious about getting this in the air.BTW this is not my first plane or build.I have a Hyperion E-meter so I will pick up a couple different props from the LHS and try them out with the E-meter.
Mike
claybuster is offline Find More Posts by claybuster
Reply With Quote
Old Jun 10, 2006, 09:50 AM
"SARGE"
sargentw's Avatar
Fairfax Station, (Northern) Virginia
Joined Jun 2003
3,150 Posts
Sounds good. Go with an 8 cells brick pack (CBP). Shoot for IB1200's or GP1100's if you can.
sargentw is offline Find More Posts by sargentw
Reply With Quote
Old Jun 10, 2006, 12:50 PM
Needs a vacation
thermlin''s Avatar
In a house
Joined Nov 2005
2,246 Posts
so it sounds like once your motor and wires are in, and the planes assembled, theres no turning back? will i need a length of wire to make the distance between motor and ESC? im planning on using a Promax cobalt 400-sound ok?
thermlin' is offline Find More Posts by thermlin'
Reply With Quote
Old Jun 10, 2006, 02:05 PM
Registered User
kdahlhaus's Avatar
United States, OH, Westlake
Joined Mar 2002
4,543 Posts
I've been doing a lot of reading here in prep of my own EZ* build. Joining the fuse with 3M removeable poster tape allows the fuse to be opened as needed. Found it at Office Max. It was on a roll like (and with) the scotch tape.
kdahlhaus is offline Find More Posts by kdahlhaus
Reply With Quote
Old Jun 10, 2006, 03:49 PM
Registered User
Syracuse, NY (USA)
Joined Dec 2004
2,727 Posts
The tail still gets glued on though right? If so, I think the two fuse halves will not come all the way apart again.

Quote:
Originally Posted by kdahlhaus
I've been doing a lot of reading here in prep of my own EZ* build. Joining the fuse with 3M removeable poster tape allows the fuse to be opened as needed. Found it at Office Max. It was on a roll like (and with) the scotch tape.
Block is offline Find More Posts by Block
Reply With Quote
Old Jun 10, 2006, 04:20 PM
Electricholics Anonymous
claybuster's Avatar
WARREN, MICHIGAN
Joined Jul 2005
1,959 Posts
Anyone ever tried this Pematex blue rtv silicone to hold the motor in instead of Goop? I 'm out of Goop but have some of this in the shop.
Mike
claybuster is offline Find More Posts by claybuster
Reply With Quote
Old Jun 10, 2006, 04:31 PM
Electricholics Anonymous
claybuster's Avatar
WARREN, MICHIGAN
Joined Jul 2005
1,959 Posts
And the picture I forgot.
claybuster is offline Find More Posts by claybuster
Reply With Quote
Old Jun 10, 2006, 06:25 PM
Registered User
Nobert's Avatar
Tucson Avra Valley, Arizona, United States
Joined Jul 2002
1,476 Posts
Mike
It will work like a charm.
Neal
Nobert is offline Find More Posts by Nobert
Reply With Quote
Old Jun 11, 2006, 11:36 AM
"SARGE"
sargentw's Avatar
Fairfax Station, (Northern) Virginia
Joined Jun 2003
3,150 Posts
Quote:
Originally Posted by thermlin'
so it sounds like once your motor and wires are in, and the planes assembled, theres no turning back? will i need a length of wire to make the distance between motor and ESC? im planning on using a Promax cobalt 400-sound ok?
There are better choices. I had a cobalt motor and it's retired (power, but runs hot and sucks batteries dead). There should be no reason to open the fuse again. Run all your wires and set everything up and check/test before gluing.
sargentw is offline Find More Posts by sargentw
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Sig Four Star 40 ARF Engine recommendations and Building Tips Daverp Beginner Training Area (Fuel) 24 Jul 12, 2009 03:38 PM
Discussion Finished building my easy star :) lee2005 Foamies (Kits) 2 Mar 02, 2007 06:10 PM
Simple 400 Building Tips? 99esq High Performance 4 Sep 10, 2001 08:07 PM
Wattage F-22 Building Tips / Pictures rcfanatic Foamies (Kits) 9 Sep 08, 2001 03:25 PM
IFO Mark3: Any last minute building tips ? volt flyer Parkflyers 13 Jun 21, 2001 04:33 PM