Aft C of G snag
Thread Starter
Aft C of G snag
hello all
I need some tips/gen/advice on sorting out an aft C of G on a small side-by-side two-seater. It requires the stick to be held forward of neutral to sustain level flight. It's tiring to fly for too long.Any sensible suggestions appreciated.
regards
TDD
I need some tips/gen/advice on sorting out an aft C of G on a small side-by-side two-seater. It requires the stick to be held forward of neutral to sustain level flight. It's tiring to fly for too long.Any sensible suggestions appreciated.
regards
TDD
Join Date: Mar 2002
Location: Midlands
Age: 71
Posts: 605
Likes: 0
Received 0 Likes
on
0 Posts
Aft CofG
2 Dead Dogs
Like the name!
Is the CofG really too far aft or are you assuming that this is so because of the stick forces required? The Cof G can be adjusted with lead, shifting the battery etc.
If it is merely a trim problem then some experimentation with a simple additional aluminium trip tab - bend it until the desired effect is achieved - should do the trick.
However, if this is a Permit aircraft then I suggest you call the PFA. THere is no doubt that they will give you all the necessary advice and contacts to sort this.
VBR
Hairyplane
Like the name!
Is the CofG really too far aft or are you assuming that this is so because of the stick forces required? The Cof G can be adjusted with lead, shifting the battery etc.
If it is merely a trim problem then some experimentation with a simple additional aluminium trip tab - bend it until the desired effect is achieved - should do the trick.
However, if this is a Permit aircraft then I suggest you call the PFA. THere is no doubt that they will give you all the necessary advice and contacts to sort this.
VBR
Hairyplane
2DD,
I'm guessing that it's a PFA permit 2-seater, in which case your best first port of call would be Francis.D.
However, if that isn't getting you anywhere, or it's somebody else's responsibility, the following information would help to answer you...
- What's the declared CG range, where are you in it.
- What are these in %smc
- What are the measured stick free and stick fixed apparent LSS gradients.
- What sort of mechanism on the elevator, horizontal stabiliser and pitch trimmer.
- What's the tailplane volume coefficient?
- What power setting are you using when this occurs, how does it vary with power.
Appreciating you may not want to jeapordise your anonymity, the type might help too ! Failing that at-least the general configuration (high/mid/low wing, ditto tail, mid/high powerplant, pusher/tractor, MTOW, power, CAS speed range).
Finally, what do you have scope to change - one can always bolt things onto surfaces, but can you change any of the following...
- Aileron droop / reflex
- Wing incidence
- Tailplane incidence
- Elevator gearing
G
I'm guessing that it's a PFA permit 2-seater, in which case your best first port of call would be Francis.D.
However, if that isn't getting you anywhere, or it's somebody else's responsibility, the following information would help to answer you...
- What's the declared CG range, where are you in it.
- What are these in %smc
- What are the measured stick free and stick fixed apparent LSS gradients.
- What sort of mechanism on the elevator, horizontal stabiliser and pitch trimmer.
- What's the tailplane volume coefficient?
- What power setting are you using when this occurs, how does it vary with power.
Appreciating you may not want to jeapordise your anonymity, the type might help too ! Failing that at-least the general configuration (high/mid/low wing, ditto tail, mid/high powerplant, pusher/tractor, MTOW, power, CAS speed range).
Finally, what do you have scope to change - one can always bolt things onto surfaces, but can you change any of the following...
- Aileron droop / reflex
- Wing incidence
- Tailplane incidence
- Elevator gearing
G
Last edited by Genghis the Engineer; 23rd Apr 2002 at 21:29.
Thread Starter
hi there
Apologies for not replying sooner. The aircraft in question is a VP-2.The exact details of the C of G range are in the post,so to speak.i'll pick your collective brains soon.
regards
TDD
Apologies for not replying sooner. The aircraft in question is a VP-2.The exact details of the C of G range are in the post,so to speak.i'll pick your collective brains soon.
regards
TDD
