Aerobatic Gross Weight

[Veetail88]

I'm a pretty big guy, I go around 290. I'd like to get some spin training, upset recovery, and basic aerobatic instruction. I'd also really like to do it in my plane. The problem is if I put any fuel in it, and a normal guy in the back seat, with chutes, we blow by the aerobatic gross weight pretty quickly.

While I know there will be a lot of folks that will say "are you crazy? Do that and you're sure to die!" or somethings along those lines, I'd like to know all ya'all's thoughts on this.

The aerobatic gross on the 8 is 1600 lbs. and that's good for 6 Gs or 9600 lbs.
So if we're at 1750 lbs and limited the aerobatics to maneuvers that would not exceed 5.486 Gs (9600 lbs again), are we good? Seems to make sense to me, and keeping the maneuvers mild I would think would pretty easily stay within that limit. Obviously we'd have to be concerned with CG and keep that as far forward as possible.

Is my thinking all messed up? Am I missing something?

[luddite42]

Originally Posted by Veetail88

Am I missing something?

That you cannot necessarily expect to limit the G to a certain number in a training environment. Once you have some skills, you can do all the basic maneuvers at no more than 3.5G all day long, but newbies receiving training are very good at screwing up things and utilizing the full 6G limit of an aerobatic airplane. You'd be cutting your margins in a situation where you need maximum margin. Choose your training aircraft and instructor carefully.

[rv7charlie]

+1
You almost certainly will fall out of a maneuver, and recovery depends on how good your instructor is, and whether one of you panics (could be the instructor :-) ).

Not saying it can't be done, but make sure both you & the instructor go in with eyes wide open & fully informed.

(BTW, you might want to fix the typo; that would be a really bad mistake if it were the actual calculation...)

Charlie

[Veetail88]

Good catch. 8 Gs plus, not so good. Corrected thanks.

[judoka5051]

Hey Jesse,

So, I figure 290 (you) + 180 (instructor) + 30 (chutes) + 100 for fuel (8 per side) = 600 lbs.

That only leaves 1000 for the airplane. A plane can be built at that weight, or even lighter (my 8A was 975), but an already built plane is a different thing entirely. Still, if your plane is 1150, you can probably cut some weight. That will at least improve your margin. Here's a post where I listed what I did to keep mine light, you can use a some of the ideas to get you closer to your target weight.

http://www.vansairforce.com/communit...&highlight=975

Lance

[SMO]

Originally Posted by Veetail88

.....I'd like to get some spin training, ..... Obviously we'd have to be concerned with CG and keep that as far forward as possible.

Spin training does not necessarily require an airplane with aerobatic g limits. My initial training in 1974 was in a non aerobatic 150, spins were part of the curriculum and fully approved for the airplane.

I spin my Rocket regularly, and while it is rated for +6, -3, I won't spin it with a passenger. Puts the CG too far back, and as far as I am aware nobody has spun the F1 EVO with a rear loaded CG - some probability of flat spinning and a question of whether it would recover.

Suggest you confirm the -8 will recover from a spin when rear loaded - Like me you probably don't want to be the first to find out if it works or not.

[David Paule]

Why not get your initial aerobatic training an another aircraft? I know you said you'd like to do it in the 8, but here it might not be appropriate.

Once you've learned some things, you can practice in your own plane, solo.

Dave

[ronschreck]

Originally Posted by David Paule

Why not get your initial aerobatic training an another aircraft? I know you said you'd like to do it in the 8, but here it might not be appropriate.

Once you've learned some things, you can practice in your own plane, solo.

Dave

+1
Spin or unusual attitude recovery training is no time to be experimenting with aft CG or heavy weight issues. Because of the commercial nature of flight training programs they cannot use experimental aircraft, however the basics of unusual attitude recovery are similar to most all conventional light aircraft. Get some training in a certified Extra, Decathlon, or Pitts then practice the procedures in your RV with confidence.

Go to IAC.org to find an aerobatic instructor near you.

[ssmdive]

Most aerobatics can be done in the 3-4G range. But that is if you know what you are doing. The next issue is the RV series have very powerful elevators. It would be very easy to exceed the G limit with an RV.

I did my 1st loop in my RV6 yesterday and I was deeply surprised by the G onset at the bottom of the loop. And while I am no expert, I placed 2nd in the Region in IAC Sportsman last year. I could see someone grabbing too much elevator at the bottom and blasting through G limit. It is a natural reaction.

And the instructor is not going to be able to prevent you from over pulling.

I'd second getting instruction in a higher G rated plane with a less sensitive elevator.

[ronschreck]

Originally Posted by ssmdive

Most aerobatics can be done in the 3-4G range. But that is if you know what you are doing. The next issue is the RV series have very powerful elevators. It would be very easy to exceed the G limit with an RV.

I did my 1st loop in my RV6 yesterday and I was deeply surprised by the G onset at the bottom of the loop. And while I am no expert, I placed 2nd in the Region in IAC Sportsman last year. I could see someone grabbing too much elevator at the bottom and blasting through G limit. It is a natural reaction.

And the instructor is not going to be able to prevent you from over pulling.

I'd second getting instruction in a higher G rated plane with a less sensitive elevator.

A plane that is overly sensitive in pitch control is likely have a center of gravity too far back. It might be a good idea to check your CG position. If it is in the aft third of the aerobatic CG range it may be too sensitive for some pilots. A higher fuel load can often correct an aft CG position and ease up on the pitch sensitivity.