AV_TrimStabilityControl

AeroVantage ~Trim, Stability & Control

Overview:

Theoretical notes re trim, stability and control sensitivity related specifically to the AeroVantage.

For general information see: OTHER: Flight Dynamics.

See Access database: FORM: Trim, Stability and Control for calculations. Is this applicable to the AeroVantage?

General Notes:

Any undesired pitching moment of the craft about the lateral axis during transition that is caused by the streamtube(s) of the forward or rear proprotor(s) might be removed by including a portion of the wing at the transition mechanism with the motor attachment frame. This will remove the offending portion from the thrust of the respective proprotor.

Longitudinal Moment in Hover:

Different proposed transition mechanisms have different arm lengths. The example below is currently based on Long Arms w/o Elbows.

The first three lines below are common to all proposed mechanisms.

Total weight = 1325 lb.
Total disk area = (34.1 ft² + 55.1 ft²) * 2 = 178.4 ft²
Disk Loading = 7.4 lb/ ft²

This is currently based on Forward and Aft Moving Elbows.

Forward arm length in hover to 25% of wing's chord; for large disk = 63.24" = 5.3 ft.

Rear arm length to 25% of wing's chord; for small disk = 89.16" = 7.4 ft.

Gap in hover is 5.3 + 7.4 = 12.7 ft.

Forward moment = [51.1 ft²* 2 * 7.4 lb/ ft²] * 5.3 ft = 4,008 ft-lb.

Rear moment = [34.1 ft²* 2 * 7.4 lb/ ft²] * 7.4 ft = 3,735 ft-lb.

The center of lift is very close; and it is very easy to make adjustment.

This is currently based on Long Arms w/o Elbows.

Forward arm length to 25% of wing's chord; for small disk = 64.7" = 5.4 ft.

Rear arm length to 25% of wing's chord; for large disk = 87.9" = 7.3 ft.

Gap in hover is 5.4 + 7.3 = 12.7 ft.

Forward moment = [34.1 ft²* 2 * 7.4 lb/ ft²] * 5.4 ft = 2,725 ft-lb.

Rear moment = [51.1 ft²* 2 * 7.4 lb/ ft²] * 7.3 ft = 5,521 ft-lb.

The center of lift is way to far aft.

The following assumes that the whole transition assembly could be moved forward 2.5 feet; which is way too far.

Forward moment = [34.1 ft²* 2 * 7.4 lb/ ft²] * 7.9 ft = 3,987 ft-lb.

Rear moment = [51.1 ft²* 2 * 7.4 lb/ ft²] * 4.8 ft = 3,630 ft-lb.

This is currently based on Scale Model of Pivoting Arms #2 1640.html

Forward arm length to 25% of wing's chord; for large disk = 11.8514 * 12 = 11.85 ft.

Rear arm length to 25% of wing's chord; for small disk = 11.8956 12 = 11.89 ft.

Gap in hover is 6.6 + 6.1 = 12.7 ft.

Forward moment = [51.1 ft²* 2 * 7.4 lb/ ft²] * 7.9 ft = 5,975 ft-lb.

Rear moment = [34.1 ft²* 2 * 7.4 lb/ ft²] * 7.9 ft = 3,987 ft-lb.

The center of lift is way to far forward.

The following assumes that the whole transition assembly could be moved aft 1.6 feet. OR the gap reduced, particularly at the front.

Forward moment = [51.1 ft²* 2 * 7.4 lb/ ft²] * 6.3 ft = 4,765 ft-lb.

Rear moment = [34.1 ft²* 2 * 7.4 lb/ ft²] * 9.5 ft = 4,794 ft-lb.

Outside Information that may relate to my concern about stability when in ground effect:

An Experimental Investigation of Ground Effect on a Quad Tilt Rotor in Hover and Low Speed Forward Flight

There is a copy of this dissertation on the Removable E drive entitled 'Quad_Rotor_Testing.pdf' & Partial hard copy.

Working Papers:

DESIGN:

Axx

MAKE:

Secondary Group:

	Trim:	No page yet.
	Stability:	Vortex Ring State etc.
	Control:	This link is currently to the 'Flight + Power Train Control'

Same Page ~ Different Craft: ~ SynchroLite ~ Dragonfly ~ UniCopter

Last Revised: November 6, 2008