HobbyKing.com New Products Flash Sale
Thread Tools
Old Oct 11, 2004, 12:37 PM
Registered User
Joined Jan 2004
19 Posts
Is my plane nose heavy?

I built & designed a plane - it uses an ips-A on six cells.
wingloading is ~6 and weight is ~8 oz
It's a pretty basic, clean design (low drag)
so far I've only used a 9x7 GWS slowfly prop

My problem is, it won's stay up. It only sustains flight below 3 feet off the ground, but once it goes up out of the ground effect, it just goes back down.

It doesn't seem to be stalling, I think i just can't hold it up there.
Does that mean it's probably nose heavy?

I would be really grateful for any suggestions people have...

Thanks in advance,
matter is offline Find More Posts by matter
Reply With Quote
Sign up now
to remove ads between posts
Old Oct 11, 2004, 01:03 PM
Registered User
Minneapolis Dntn, Minnesota, United States
Joined Aug 2003
93 Posts
Matter, What is the wing span? You are probably out of ground effect already at 3ft.

What are you using for a battery? Also you might try a seven cell battery for a little extra power.

Scalf is offline Find More Posts by Scalf
Reply With Quote
Old Oct 11, 2004, 01:11 PM
Motors beat engines!
Milwaukee Wisconsin, United States
Joined Feb 2001
4,564 Posts
Its possible that its nose heavy, but what it definately is ins underpowered.

With only 6 cells, your probally drawing well under 2 amps, maybe only 1.5 on 7v for about 12 watts or so for only 24 watts/lb.

It sounds like you have around 175 in/sq, so I punched it into motocalc, and got a stall speed of 12mph, a pitch speed of only 20 mph, ( you should have at least 30mph) and a max possible climb rate of 88 ft/.min at 3 degrees.

Its no wonder you could'nt climb.

Easy solutions?

1) keep your existing battery, but go to a ips s2 with 7x6, still won't be great, but it should fly.

2) Go to a different battery. 3s Lithiums with a 7x6 on your existing motor will get you all the way up to 350 ft/min climb, a very reasonable number for a parkflyer.

Good luck!

Dean in Milwaukee
DeaninMilwaukee is offline Find More Posts by DeaninMilwaukee
Reply With Quote
Old Oct 11, 2004, 01:46 PM
Live to ride... and fly!
Tres Wright's Avatar
Forney, TX
Joined Mar 2002
15,165 Posts
6 cells won't cut it for sure. Go with 7 cells Nicad or 8 cells NiMH; or try li-pos as Dean suggested. Whatever you choose, go light on the battery pack.
Tres Wright is offline Find More Posts by Tres Wright
Reply With Quote
Old Oct 13, 2004, 01:42 PM
Registered User
Joined Jan 2004
19 Posts
Thanks Everyone!

span is 30" - area is 195 sq in

Brian - I agree, it's probably out at 3 feet.
Thanks a lot for the info Dean.

The problem is I'm too cheap to buy a differrent battery or motor.

Is there any chance a diferrent prop would work a little better?

I might be getting a brushless soon (himax outrunner or typhoon 6) but I'm not sure it will fit this plane.

Thanks again - Matter
matter is offline Find More Posts by matter
Reply With Quote
Old Oct 13, 2004, 01:56 PM
AMA 353531
rdeis's Avatar
United States, CO, Colorado Springs
Joined Aug 2003
6,589 Posts
Not really. Dropping the pitch speed (with a new prop and/or gearing) will give you a bit more thrust, but when the prop is moving that close to the stall speed it really doesn't want to fly.
rdeis is offline Find More Posts by rdeis
Reply With Quote
Old Oct 13, 2004, 03:26 PM
Nickel what?
Phreakish's Avatar
Prescott, Arizona, United States
Joined Jan 2003
2,365 Posts
you'd have to change gearing to get another prop to work better... Just dont have the revs to get the prop to pull the airframe
Phreakish is offline Find More Posts by Phreakish
Reply With Quote
Old Oct 13, 2004, 03:30 PM
Australian in the USA
Paranoia's Avatar
Orange, CA USA
Joined Aug 2002
816 Posts
Tres Wright is correct you need a 7 or 8 cell pack or 2cell Li poly's. The power system can't provide what you need.

The other way is to decrease the wing loading, "make the plane lighter"
Paranoia is offline Find More Posts by Paranoia
Last edited by Paranoia; Oct 13, 2004 at 03:38 PM.
Reply With Quote

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Is my plane tail heavy? punkin438 Fuel Warbirds 9 Dec 28, 2006 08:52 AM
Why does a nose heavy plane climb during a dive test? EABiker Modeling Science 4 Aug 06, 2005 05:54 AM
Why a plane goes UP in a dive if it's NOSE heavy? Flying Cat Modeling Science 21 Sep 26, 2002 03:31 AM
My LMH110 is getting a bit nose heavy! Tom Viper Electric Heli Talk 2 Nov 16, 2001 01:37 AM
Trexlers,,,I have a flat on my plane cruzomatic Electric Plane Talk 10 May 10, 2001 11:14 PM