need to talk with an aeronautical engineer

[scsmith]

Wow, that seems like a lot of trim to me...

It is likely connected to where your c.g. is.

On my RV-8, at cruise the trim tab has very little up deflection (nose-down trim). In the pattern, it is almost all the way down (nose up trim). Next time at the hangar, I'll measure the angles for you.

But I can imagine that an RV-7 at aft c.g. might need a fair bit of up-tab (nose-down trim) at cruise. But 30 degrees seems like a lot!

One other possibility would be if the horizontal stabilizer was mounted at the wrong incidence. A small error in incidence would take a lot of trim-tab to compensate for. I would suggest you review the plans for H-tail attachment and make sure you have the right shim height under the H-tail front and/or rear spar.

 

[Low Pass]

I might add that in the auto industry electric propulsion is poised to finally really take off soon.

Even Chevrolet, who has drug their heels kicking and screaming into the electric power revolution, is getting ready to release the Volt for commercial sale this coming fall.
....

Say what?! You gotta cut down on your mainstream media news consumption. Chevy was the first (late 20th century) electric vehicle from a major manufacturer with their EV1. It was about 10-15 years ahead of it's time.

 

[49clipper]

49clipper

I checked the incidence on the H. stab an its -.5 degrees. (should be 0, I know) I moved it temporarily to +.7 and it made a small difference in that at cruise the tab was up 22 degrees. W&B is 70.7" EWCG which is within reasonable limits although a little more aft than I would like. Most -6's are about 69.5" or so.
Vans says their -6 & -7 are both like that, although I cannot find anyone with the tab up that much. Just seems odd to me. The elevator counterbalance arms are up about .5" best I can tell at cruise and that seems to be normal and in agreement with Vans.

Beats me.

 

[RVbySDI]

Say what?! You gotta cut down on your mainstream media news consumption. Chevy was the first (late 20th century) electric vehicle from a major manufacturer with their EV1. It was about 10-15 years ahead of it's time.

I would never consider the EV1 as a viable vehicle from GM. There was no way that was ever going to be mass produced for the public. What I was referring to was the fact that after all these years Chevrolet is poised to finally release an electric vehicle for sale to the public.

The truth is if you want to talk about GM's foray into electric vehicle manufacture you can go further back than the EV1. I recall their lame attempt to build an electric vehicle in the 80's using a Chevrolet Van filled with led acid batteries. It weighed about as much as a Sherman Tank, had a top speed of maybe 45 MPH and an endurance of a couple of hours before it needed charging. They concluded from this test vehicle electric vehicles were not a viable platform for future production vehicles. They used this test vehicle to justify their decision to stop further testing of electric propulsion.

This is why I mentioned the notion that "even" Chevrolet (GM) is getting back into the game when it comes to producing a vehicle for sale to the public.