Slow 7A

[hecilopter]

Originally Posted by wv4i

Why so high? High prop rpm, low pitch, at cruise, will slow you down for sure, but never tested how much. I run my RV6/180hp/CS prop at approx 2300 rpm in crz. Note that there is an avoid range below 2250. Brings the fuel burn way down also, with MP held constant.

For a max speed test you need to run a C/S full throttle and near 2700 RPM to get full available HP from the engine. This should be the fastest configuration.

[Jim P]

You probably want to play around with the settings a little. With max MP, you may find that at higher airspeeds, the props happy-place may be around 2600 or so, not the full 2700 RPM.

[nturner]

What are people getting in RV 7a's with 180hp and FP prop?

[BigglesRV7A]

Richard,

I'm with Rusty on this one! Unless your RPM is at 2700, you will not be developing rated power of your engine. Not sure what the difference is between 2600 and 2700rpm though it means the HP available is less hence less max TAS.

Cheers, Greg

[Jeff Vaughan]

RV7A FP Sensenich 157 knots, 169 knots w wheel pants
8000' wot 75%

[fodrv7]

Originally Posted by rwtalbot

G?day Everyone,

IMy first thought was that the shim on the HS may need adjustment, but the more I think about it that may not be the case.

RV7A ? Phase I Flight Testing

Richard,
I doubt that the Tailplane incidence has any effect on your TAS.

When I set my tailplane incidence, I inserted the appropriate spacer (a 1/4" drill bit from memory.
The plans called for an incidence of 0?, but like all Vans measurements there was no tolerance. ie. plus or minus 20 minutes.

When I checked the incidence it was not 0? and so I added slightly larger drill bits until the incidence was close to zero.
I checked with my mate and he simply used the advised 1/4" bit, so my tailplane ought to have been closer to 0? than his.

However, to my dismay, his RV7 was a few knots faster than mine.

Pete.

[roadrunner20]

Once your engine is broken in & add the fairings, you should gain about 20kts. I had the same concerns and speeds you're seeing.

[Davepar]

Here's an online form for calculating TAS from GPS numbers: http://www.dualrudder.com/tas.php
And the source if anyone's interested: http://www.dualrudder.com/tas.phps