Re: Per the '10-'11 AMA rules for LPP

From: leop12345 <leop_at_lyradev.com>
Date: Sat, 05 Mar 2011 18:49:56 -0000

The LPP class has become more sophisicated as the years roll by and even more so lately with the Pro/Am event at the USIC. To build an LPP capable of over 16 minutes Johnson City and over 18 minutes at LH takes some careful design and serious consideration of the weight budget.

With full wind torques often well over 1.0 oz-in, there are great stresses on the motorstick. And the resulting motorstick twist puts great stresses on the wingposts and the wing spars. The best LPP's have litte or no ballast because the builders use all the weight allowed to build stiffer parts as they develop their initial designs and determine the optimum cg location, etc.

A 5/16" by 1/4" solid motorstick may look like part off of a battleship but even a motorstick of that size can bend too much if not well built out of good balsa. Even wing spars fabricated from super stiff carbon rods or out of balsa with boron fiber reinforcement can flex enough to cause a wing to tuck after a high torque launch or in a dive (after a ceiling or girder bump) if the design of the spar and wing is not correct.

So, even though many people consider LPP's to be big fat ugly ducks, they can be quite beautiful swans.

Leo
Bloomington IN

--- In Indoor_Construction_at_yahoogroups.com, "Don DeLoach" <ddeloach@...> wrote:
>
> A battleship.that's an excellent analog!
>
>
>
> Don D
>
>
>
> _____
>
> From: Indoor_Construction_at_yahoogroups.com
> [mailto:Indoor_Construction_at_yahoogroups.com] On Behalf Of Ed
> Sent: Saturday, March 05, 2011 7:29 AM
> To: Indoor_Construction_at_yahoogroups.com
> Subject: RE: [Indoor_Construction] Per the '10-'11 AMA rules for LPP
>
>
>
>
>
>
> Don, Thanks again. I think it was a stupid question to start with. LPP's are
> built like a battleship!
>
> Ed
>
>
>
> -------Original Message-------
>
>
>
> From: Don <mailto:ddeloach_at_...> DeLoach
>
> Date: 3/4/2011 9:12:18 PM
>
> To: Indoor_Construction_at_yahoogroups.com
>
> Subject: RE: [Indoor_Construction] Per the '10-'11 AMA rules for LPP
>
>
>
> Ed
>
> LPP does not allow anything but a solid piece of wood for the motorstick. No
> bracing, boron, carbon, or rolled tubes.
>
>
>
> Don DeLoach
>
> Editor, NFFS Free Flight Digest
>
>
>
>
>
> _____
>
> From: Indoor_Construction_at_yahoogroups.com
> [mailto:Indoor_Construction_at_yahoogroups.com] On Behalf Of Edward
> Sent: Friday, March 04, 2011 3:05 PM
> To: Indoor_Construction_at_yahoogroups.com
> Subject: [Indoor_Construction] Per the '10-'11 AMA rules for LPP
>
>
>
>
>
> Sec; 21.3.6; "No gadgets of any kind are permitted on the model" Does this
> mean no boron or bracing wires? Rules only mention VP props etc. There is NO
> mention of Boron or Bracing wires. Does this mean it's of to use them OR
> does NO GADGETS mean NOTHING BUT WOOD !!!
> Ed Berton
> Brevard,NC
>
Received on Sat Mar 05 2011 - 10:49:58 CET