SMALL - espritmodel.com SMALL - Telemetry SMALL - Radio
Reply
Thread Tools
Old Mar 30, 2002, 08:40 PM
AMA 697691
Rochester, NY, USA
Joined Aug 2000
8,406 Posts
Acro-Bipe (Firefly-powered)

Hi,

When the wind blows...I build. Here is my converted $10 Acro-Bipe powered by the improved 4:1 Astro Flight (AF) Firefly coreless Cobalt motor. The tiny motor fits right into the stock nose of the Acro-Bipe! I used a small piece of masking tape around 1/2 the diameter of the motor to create a snug fit. Now that's an easy motor mount!

My Bipe weighs in at 3.7oz using an 8-cell, 120mAh, NiMH pack. This provides amazing power to the Gunther 5x4 prop at 850mA. The AF ESC for the Firefly has very nice linear control.

I used a GWS R4-P receiver and two GWS Pico servos for elevator and aileron control. My aileron control horns are typical biplane-style that extend to both sides for a future connection option up to the top wing.

Click here for a larger image.
Greg Covey is offline Find More Posts by Greg Covey
RCG Plus Member
Last edited by Greg Covey; Mar 30, 2002 at 09:06 PM.
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 30, 2002, 08:49 PM
AMA 697691
Rochester, NY, USA
Joined Aug 2000
8,406 Posts
The finished bottom reveals tiny carbon rods to help support the fragile ailerons. These were purchased from Air Dynamics.

I used the switch/charger board from one of my old COX Viper projects. I've found that enclosing the battery for a self-contained unit works well on these tiny foam models. I just plug in the charge jack to peak the cells.

Click here for a larger image.
Greg Covey is offline Find More Posts by Greg Covey
RCG Plus Member
Latest blog entry: Greg's Web Hangar
Reply With Quote
Old Mar 30, 2002, 08:56 PM
AMA 697691
Rochester, NY, USA
Joined Aug 2000
8,406 Posts
The elevator servo fits right in the slot used to anchor the stock rubber band.

Thin white hinge tape was used to help support the elevator that was never removed from the stabilizer. A tiny rod was bent to join the two elevator halves together. The whole stabilizer/elevator assembly was then slid from the rear after making a razor slice in the rudder. The assembly and rudder were then glued with white Elmers glue.

Click here for a larger image.
Greg Covey is offline Find More Posts by Greg Covey
RCG Plus Member
Latest blog entry: Greg's Web Hangar
Reply With Quote
Old Mar 30, 2002, 09:02 PM
AMA 697691
Rochester, NY, USA
Joined Aug 2000
8,406 Posts
A close-up of the aileron linkage reveals the special servo arm created from 3 seperate arms.

The paint was removed entirely from the bottom wing using Scotch tape. Just press on and peal off, it's that simple! The ailerons were much easier to tape on the top side after the yellow paint was removed.

Click here for a larger image.
Greg Covey is offline Find More Posts by Greg Covey
RCG Plus Member
Latest blog entry: Greg's Web Hangar
Reply With Quote
Old Mar 30, 2002, 09:57 PM
Go Dawgs!!!!!!!
David Hogue's Avatar
USA, NC, Clayton
Joined Feb 2001
5,882 Posts
Greg,

Why the long servo arm? Seems to me you are losing a lot of torque and centering ability. One click of trim on your tx is gonna make a huge difference at the end of that arm...you may have problems trimming the ailerons in flight. JMO, but I would just angle the pushrods out to the ail horns like this / \. I had one of these bipes and sold it...I paid 19.99 for it locally, and now I know about the site that sells them for 8.99, I may just have to get a couple!!

Good luck,
David Hogue
David Hogue is online now Find More Posts by David Hogue
Reply With Quote
Old Mar 30, 2002, 10:37 PM
Registered User
Jeff Meyers's Avatar
Fayetteville, GA
Joined Oct 2000
3,663 Posts
That's cool Greg.

I've always wondered what people use that firefly for. I can't recall ever seeing an application for it.

I sure would like to see some video of that little bipe.

Regards,

Jeff
Jeff Meyers is offline Find More Posts by Jeff Meyers
Reply With Quote
Old Mar 31, 2002, 09:51 AM
Registered User
Fly_joy's Avatar
Rochester, NY
Joined Mar 2001
226 Posts
Nice job.

Larry
Fly_joy is offline Find More Posts by Fly_joy
Reply With Quote
Old Mar 31, 2002, 03:27 PM
AMA 697691
Rochester, NY, USA
Joined Aug 2000
8,406 Posts
Thanks guys. I'll let you know how it flies soon.

David,

You have a good point. I get so used to my Futaba Super-8 computer radio that I forgot to mention that this setup requires that the gain be turned way down. The assumption here is that you have a computer radio.

It seems reasonable gain now but I can always use other holes closer to the servo for additional reduction.

Larry,

Hopefully, you'll be coming to the Xerox Gym on April 13th and you can watch me slam it into a wall.

Here is a picture of some of the components that I used.

Click here for a larger image.
Greg Covey is offline Find More Posts by Greg Covey
RCG Plus Member
Latest blog entry: Greg's Web Hangar
Reply With Quote
Old Mar 31, 2002, 05:05 PM
Registered User
Fly_joy's Avatar
Rochester, NY
Joined Mar 2001
226 Posts
I'll probably be hitting the walls before you do

btw, what is the wing loading of the bipe?
Fly_joy is offline Find More Posts by Fly_joy
Reply With Quote
Old Mar 31, 2002, 05:51 PM
Registered User
Eric S.'s Avatar
Auburn Ca.
Joined Dec 2001
37 Posts
Acro-bipe

Fire-Flys work great!
3.2oz with 8 50 Nicd two Wes-tech servos, GWS reciever. elevator rudder and throttle, And they paint good too. Model Masters Acryl brushed on.
Eric S. is offline Find More Posts by Eric S.
Reply With Quote
Old Mar 31, 2002, 08:21 PM
AMA 697691
Rochester, NY, USA
Joined Aug 2000
8,406 Posts
Eric,

Awesome looking Acro-Bipe!!! My God, you even painted the girl! I love the improved landing gear too.

I have a few questions for you...

I was going to use the 50mAh NiCds but I only had a 6-pack lying around with some loose cells that I could have added to it. I then spotted an 8-cell 120mAh NiMH pack that was similar size and weight to the 50mAh NiCd cells. Have you compared the two cell types for performance?

Is your AF Firefly the improved metal gearbox and boosted ESC current limit?

I notice that you are using a GWS prop. Have you tried the Gunther prop?

Regards.
Greg Covey is offline Find More Posts by Greg Covey
RCG Plus Member
Last edited by Greg Covey; Mar 31, 2002 at 08:25 PM.
Reply With Quote
Old Apr 01, 2002, 12:01 AM
Rhinebeck CD-99,00,01,02
Tom Smith's Avatar
New Bern, NC
Joined Mar 2001
3,071 Posts
Greg, neat little bird. Think it will fly OK on ailerons with that much dihedral. Have you been out to the pond with your Aventura II yet. I flew mine again 2 days ago. Man I like the way that thing flys off water.
Gofli, where can I get one of these little bipes for $10. Tom Smith, CD, Rhinebeck Jamboree
Tom Smith is online now Find More Posts by Tom Smith
Reply With Quote
Old Apr 01, 2002, 12:31 AM
Go Dawgs!!!!!!!
David Hogue's Avatar
USA, NC, Clayton
Joined Feb 2001
5,882 Posts
Tom,


Here tis:

http://www.storeofwonder.com/store.html


Later,

David
David Hogue is online now Find More Posts by David Hogue
Reply With Quote
Old Apr 01, 2002, 02:57 AM
Registered User
Eric S.'s Avatar
Auburn Ca.
Joined Dec 2001
37 Posts
Acro-Bipe

Greg.
Yes I have used the 120 Nimh cells and they work great! I had a problem with my pack and they went thermal runaway and melted the inside of the plane, luckly its only ugly on the inside. The gear box is the old one and the speed control is from MTM and has no current limit. The GWS prop is the third one I've tried and is the best so far the old prop would only keep the plane up at full throtle now I can cruse at half throtle and stay up much longer. When I put in a new pack of 120 Nimh I'll get 8 or more minutes duration. I have not tried the gunther prop yet, it's not as pretty.... Eric.
Eric S. is offline Find More Posts by Eric S.
Reply With Quote
Old Apr 01, 2002, 03:35 PM
AMA 697691
Rochester, NY, USA
Joined Aug 2000
8,406 Posts
Tom,

It's too cold for me to pond fly yet.

A local float-fly is on May 18th so I hope to get my Aventura II wet then.

Eric,

Where did you end up with your CG on the Bipe?
Greg Covey is offline Find More Posts by Greg Covey
RCG Plus Member
Latest blog entry: Greg's Web Hangar
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Acro Bipe and RFFS-100 dhurd Scratchbuilt Indoor and Micro Models 89 Jun 03, 2003 06:26 AM
Fyi about Acro Bipe and Viper. Wilber Scratchbuilt Indoor and Micro Models 6 Apr 26, 2002 05:34 PM
Acro-Bipe CG with Firefly setup? boomerace Scratchbuilt Indoor and Micro Models 9 Apr 17, 2002 02:30 PM
Acro Bipe Wilber Scratchbuilt Indoor and Micro Models 7 Apr 05, 2002 02:47 PM
Store of Wonder Acro Bipe? Acer Scratchbuilt Indoor and Micro Models 9 Apr 04, 2002 11:08 AM