Full power static RPM check?

[docskj]

I am pending airworthyness inspection on an RV-9A. I was wondering how many people did the full power static RPM check prior to first flight. I understand that the tail should be tied, but full power on the ground makes me a bit nervous--images of creating a new youtube video of a hanger falling on top my plane or the tail coming off come to mind. Having a prop speed issue on the first flight does not sound too great either. I have a certified Lycoming 320 and the standard Hartzell prop combo.

[Brantel]

Tie it down and chock the wheels. Most RV's can't hold a full power runup with brakes alone since the tires will actually slide on the pavement (if the brakes are broken in, if they are not, they won't hold).

[Allen231ah]

I did 1 full power run-up on my -8 b/4 the first flight , I tied every place that could be tied down . I was concerned the aircraft would nose over , not an issue with your A . Be sure you check the area for small pebbles get the oil temps up in normal range and don't leave full power in for any longer than is needed for the test run . Let it idle for a bit to cool down before shut down.

Another good test to do before first flight is a fuel flow , on a carbed engine you want to see 20 GPH min through the carb at climb out angle . This can be accomplished by removing the drain plug from the back of the carb , run the boost pump for 1 minute , measure the fuel and do the math for 1 hr . This test should be done with the tail in the lowest position possible to simulated climb out .

[trib]

I did it on my 6A and was concerned about stressing the tail. I used cargo straps in a y-type configuration tying the mains to the hitch on my van, which was parked behind the airplane about 15 feet. I also chocked the wheels. The wheel pants and gear leg fairings were not installed at this point, so it was easy using the straps on the gear legs. Afterwards, I figured out the straps to the van were definite overkill. All you need are the chocks and the brakes. This was with an O-360 and sensenich metal prop.

[David-aviator]

Last time I did a full power static check, all tied down and secure, it cost me over 2 grand to repair the prop. It sucked up a stone from the hangar pad edge some 20' distant.

Its a lot easier to do it on a nice long runway. Push it up to WOT, check the rpm and coast to a stop. The only useful information is rpm, to check for take off power. CS should be around 2600, FP around 2200.

You can not run it long enough on the ground to check anything else without risking an over heat.

[kentb]

So you can set the prop to get full power. Also a good check for oil/fuel leaks.
I did this with out the cowl and a buddy standing by with the fire extinguisher.

Kent

[carl nank]

I used put my truck behind my 7A and used a chain, hooked to the tail tie down. Then wrapped the chain around and through some holes on the aft frame of the truck. Pulled on the tow handle of the airplane to pull the plane as far forward as possible while a friend chocked aft of the main wheels. That kept the chain tight. Then I positioned the other chocks forward of the main wheels with about an inch gap. This would give some clearance so the mains would not run over the chocks if the chain tightened some more at full power.

I am glad I did this procedure as while I SLOWLY advanced the throttle, the RPM went over 2700 RPM, and almost 2800 RPM before I was able to pull the power off. My Superior book says to look for 2650 rpm and not over 2700 rpm.

To adjust I turned the center screw on the prop IN 1 full turn. On second test the rpm was a little slow so I backed off the adjustment some. I still need to test it one more time.

NOTE, ALSO CHECK YOUR IDLE STOP RPM. Mine was too slow.

I hope to do first flight this weekend.

[Ron Lee]

I don't see the positive benefit to possible negatives.

For most people, you can climb just fine with less that full power. 1800 RPM or so should tell you if you have CLOSE to full power. If the RPM on a constant speed prop goes too high dial it back...is it that blue knob?

[JonJay]

What surprises me is that in all the years I have been around RV building and with all of the projects I have been around, and all the RV people I know, I have never heard of a full power ground run up as even being discussed as an option, let alone witnessed one.

My engine came from Aerosport, governor installed. I have never needed to adjust it. I am not a big fan of fast taxi's, heard about too many fast departures from the runway, so I let'er fly on my first flight, checked my RPM's, and rotated. It was about that fast too....

I would be curious to hear from a few of the really experienced people as I still consider myself a novice with only 15 years of exposure to RV's.

[Bavafa]

Originally Posted by Ron Lee

I don't see the positive benefit to possible negatives.

For most people, you can climb just fine with less that full power. 1800 RPM or so should tell you if you have CLOSE to full power. If the RPM on a constant speed prop goes too high dial it back...is it that blue knob?

The prop governor might not be set right and consequently the RPM will go past its maximum allowance. While on the first flight, there is plenty going on so the pilot might not catch that.

This was the case for me, but luckily I had run a test on the ground for two reason. First to make sure there is no fuel issue while in a climbing attitude and we run it for one full minute, second to check my RPM. Sure enough at full power, I was going pass 2700 and had to adjust both static and governor to limit it below 2700 RPM.

My test was done by chocking the mains, holding the break and having two friends holding the tail down.