HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Jul 02, 2002, 12:18 AM
Las Vegas Realtor
Inari's Avatar
Las Vegas
Joined Feb 2002
1,114 Posts
14" Tomahawk RFS-100

I got the bug for tiny-size and the RFFS-100 arrived today. So I had to make a plane for it this evening. How about a Piper Tomahawk? After all, T-tails with this system require no complicated pushrods. Yeah!

Details:

- RFS-100 System (Dave H, do I get merchandise credit for the advertising on the wing?)

- KP00 motor w/U80 prop

- 140mAh LiPoly (from Bob Selman, others carry it too)

- Fuselage is foam core, all else is styrofoam plate (Hefty 10.25", very good stuff!)

- Wingspan 14.25" / 365mm

- Total weight 0.9 oz / 26 g (yes, really!)

I did some quick powered tosses in the alley. Looks like it will fly. It was too windy to try to really fly it around but the few tosses showed plenty of power and decent glide. I will give you a better flight report when I find a better place to fly it with no wind.

Yeehaw!
Inari is offline Find More Posts by Inari
Last edited by Inari; Jul 02, 2002 at 12:21 AM.
Reply With Quote
Sign up now
to remove ads between posts
Old Jul 02, 2002, 12:19 AM
Las Vegas Realtor
Inari's Avatar
Las Vegas
Joined Feb 2002
1,114 Posts
Right side
Inari is offline Find More Posts by Inari
Reply With Quote
Old Jul 02, 2002, 12:19 AM
Las Vegas Realtor
Inari's Avatar
Las Vegas
Joined Feb 2002
1,114 Posts
Left
Inari is offline Find More Posts by Inari
Reply With Quote
Old Jul 02, 2002, 12:20 AM
Las Vegas Realtor
Inari's Avatar
Las Vegas
Joined Feb 2002
1,114 Posts
Top (boring)
Inari is offline Find More Posts by Inari
Reply With Quote
Old Jul 02, 2002, 12:27 AM
Registered User
planekrazy's Avatar
Redwood City, CA USA
Joined Mar 2002
495 Posts
Great job! That's awesome

Wow is that about 50 sq/in of wing area?
planekrazy is offline Find More Posts by planekrazy
Reply With Quote
Old Jul 02, 2002, 01:05 AM
Las Vegas Realtor
Inari's Avatar
Las Vegas
Joined Feb 2002
1,114 Posts
Thanks. It's about 43 in²
Inari is offline Find More Posts by Inari
Reply With Quote
Old Jul 02, 2002, 07:22 AM
Registered User
dhurd's Avatar
Buffalo, New York
Joined Jan 2002
1,024 Posts
Please let us know how it flies!!

Brings back the old flight training days.
dhurd is offline Find More Posts by dhurd
Reply With Quote
Old Jul 02, 2002, 08:21 AM
in persuit of low wing loading
Gordon Johnson's Avatar
Boston, Mass
Joined May 2001
6,430 Posts
John,

Looks really nice.

I'd urge you to at the very least use the celo technique (on Graham's site) to fix the terminals in place on the LiP cell. At least one person has shorted one of these out when the terminals touch. I think in a crash or hard landing you have a reasonable chance of shorting out the leads or tearing one off. See the thread on the fragile nature of these leads. Better yet, order some clear heat shrink from http://www.airdyn.com . Gabe has a deal where you mail him a self addressed and stamped envelope and a couple of bucks and you get a sample of whatever size heat shrink you want. You would get more than enough for a bunch of LiP cells. I can't recommend Gabe's lighweight clear heat shrink enough. BTW, you could get some Zepron foam from him at the same time.
Gordon Johnson is offline Find More Posts by Gordon Johnson
Last edited by Gordon Johnson; Jul 02, 2002 at 08:24 AM.
Reply With Quote
Old Jul 02, 2002, 12:17 PM
Las Vegas Realtor
Inari's Avatar
Las Vegas
Joined Feb 2002
1,114 Posts
Yep, Gordon, I already found out about the terminals tearing See my other thread I posted the same night. I'll go look at Grahams site.
Inari is offline Find More Posts by Inari
Reply With Quote
Old Jul 02, 2002, 02:32 PM
Las Vegas Realtor
Inari's Avatar
Las Vegas
Joined Feb 2002
1,114 Posts
I tested her in an open field today. She flew in trim and could turn okay but the elevator had problems. I could see that the elevator would just oscillate (flap) when up-elevator imput was given. It works fine on the ground. Perhaps it was because it was too windy or maybe just a weak coil? I do have a bit of counterbalancing area on the elevator, maybe it needs more.

I may just build a slower bird for the next project.
Inari is offline Find More Posts by Inari
Reply With Quote
Old Jul 02, 2002, 02:55 PM
in persuit of low wing loading
Gordon Johnson's Avatar
Boston, Mass
Joined May 2001
6,430 Posts
John,
Are you getting 45 degrees or so deflection up and down from your elevator when the plane is on the ground? If not, it's probably CA has wicked out into your rubber band hinge and hardened it so it won't flex as easily. It doesn't take much. I have never heard of a weak actuator since the windings are identical between units. When assembling the control surfaces, I hook them up to the RFFS-100 and test individually before gluing the rudder and elevator together or on the plane. This way if I don't get the deflection I need, then it's easy to remove the rubber and start again. Use medium CA, apply with a toothpick, and use accelerator if needed to stop the CA from wicking out into the middle of the hinge. It doesn't take much to make the actuator be overwhelmed.

We need to start a sticky thread with RFFS-100 tips, hints, and FAQ. There is nothing that difficult to these things. They are just different than our usual installation of HS55 servos and pushrods. It's an acquired skill. Dan, I'll let you start one.

How slow do you want to go? My Stechmücke (see my site) will fly at about 4-5 mph.
Gordon Johnson is offline Find More Posts by Gordon Johnson
Last edited by Gordon Johnson; Jul 02, 2002 at 02:57 PM.
Reply With Quote
Old Jul 02, 2002, 03:36 PM
Las Vegas Realtor
Inari's Avatar
Las Vegas
Joined Feb 2002
1,114 Posts
Thank you for the hints. Yep, the elevator moves about 40° on the ground. But in the air, it looks like the airflow is pushing the elevator back towards neutral whilst the coils battle back. Thus it sort of flaps up and down (actually, up and neutral). I'll play with is more and see if I can't improve the geometry. I also ordered some magnets from wonder magnet to see it that helps.
Inari is offline Find More Posts by Inari
Reply With Quote
Old Jul 02, 2002, 04:07 PM
Las Vegas Realtor
Inari's Avatar
Las Vegas
Joined Feb 2002
1,114 Posts
Hmm, well it looks like 7 grams of weight made a huge difference. I just flew it on the 140mAh LiPoly vs. 3cells of NiMH 120mAh and now I could control it (Well the 10mph winds were really controlling it more than me but it did work.). That was fun. Now to fly it with no wind....
Inari is offline Find More Posts by Inari
Reply With Quote
Old Jul 02, 2002, 09:30 PM
Registered User
dhurd's Avatar
Buffalo, New York
Joined Jan 2002
1,024 Posts
John,
You may also want to reduce the size of your elevator. It doesn't take a whole lot of surface area with these small aircraft to get the desired control. We've had instances where we got a lot more response out of an airplane after we trim the control surface down some.
dhurd is offline Find More Posts by dhurd
Reply With Quote
Old Jul 02, 2002, 09:47 PM
Las Vegas Realtor
Inari's Avatar
Las Vegas
Joined Feb 2002
1,114 Posts
Thanks Dan. Welp, I've already retired the Tomahawk. But I'm about to embark on a new craft so I'll keep that in mind. Thanks for the phone call today regarding my order. By the way, late this afternoon I was able to successfully wind my own coil so I'm not as desperate for the new coils, although I would perfer the original.
Inari is offline Find More Posts by Inari
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
CR-2 lithiums with RFS-100 fritts Scratchbuilt Indoor and Micro Models 6 Mar 19, 2002 11:35 AM
RFS-100 isn't working for me? Crasher Scratchbuilt Indoor and Micro Models 29 Mar 14, 2002 12:01 AM
Daren, and other CG maestros "F-14" Admiral_Red Electric Ducted Fan Jet Talk 33 Mar 04, 2002 02:50 PM
RFS-100 Wire Diagram fritts Scratchbuilt Indoor and Micro Models 1 Feb 22, 2002 11:51 AM
14" Pro Bow foam cutter problems J Morgan Power Systems 3 Jan 07, 2002 10:12 PM