New top end, bad ground-run RPM

[pierre smith]

Steve,
Our Catto is pitched for max cruise speed and we only get 2200 static. That's what Craig siad it would do. He also said that with a reasonably good 0-360 we will more than likely exceed Van's numbers and we do, by 4 MPH for a 202 TAS at 2700 RPM.

Regards,

[bucaronco]

Originally Posted by Kevin Horton

Engine Type Certificate Data Sheets (TCDS) won't specify a minimum static rpm, as that depends on the prop that is installed. An aircraft TCDS might specify a minimum static rpm, but there are no TCDSs for RVs, as they don't have type certificates.

Kevin..

In aircraft with type certificates, it's true, I think, that the TCDS is associated with the aircraft; and homebuilts have no type certificate. However, my A&P has told me that our O-320 has a data plate on it which states, "TC274", and lacking other guidance to establish engine limits, I have googled-up TCDS no.E-274 (covering O-320-B3B ... our engine), dated 9-13-2005.

This TCDS has no static runup RPM, but it does address rated HP (160) and full throttle RPM (2700) at sealevel.

My question for the DAR's and A&P's out there, is: would this TCDS not be considered as acceptable data for the RV6 even though we do not have a TC for the airplane. Normally accepted maintenance practices would be derived from the manufacturer's approved maintenance Manual, but how do we know that the data we are referencing, is in fact, acceptable data to use in determining the safe operating condition of the airplane?

[bfilarsky]

Well, I'm not an A&P, but I can tell you for certain you will not get max RPM out of an engine at full power with a fixed pitch prop without moving. The Lycomings I've flown with a fixed pitch prop won't hit more than about 2300 RPM in a static runup.

Sounds to me like a non-issue.

[brenegan]

Originally Posted by bucaronco

Kevin..

In aircraft with type certificates, it's true, I think, that the TCDS is associated with the aircraft; and homebuilts have no type certificate. However, my A&P has told me that our O-320 has a data plate on it which states, "TC274", and lacking other guidance to establish engine limits, I have googled-up TCDS no.E-274 (covering O-320-B3B ... our engine), dated 9-13-2005.

This TCDS has no static runup RPM, but it does address rated HP (160) and full throttle RPM (2700) at sealevel.

My question for the DAR's and A&P's out there, is: would this TCDS not be considered as acceptable data for the RV6 even though we do not have a TC for the airplane. Normally accepted maintenance practices would be derived from the manufacturer's approved maintenance Manual, but how do we know that the data we are referencing, is in fact, acceptable data to use in determining the safe operating condition of the airplane?

Ron,
There are specific TCDS' for Engines, Airframes, Propellers and Appliances. It's been implied in this thread, but I thought I'd make that clear for you. You'll find the static runup RPMs on the Airframe TCDS not Engine TCDS. The Airframe TCDS specifies conditions and limitations, which includes propeller data configuration and thus includes static runup RPM (as well as limitations such as avoiding continuous operation between 2100-2250 RPM, for example). So when you say 'acceptable data for the RV6', it's not equalivent since you are talking about an Airframe TCDS (and as already pointed out here, there is none for uncertified aircraft).

You happen to google right Engine TCDS revision for that engine, but here's an official FAA link to help you the next time: http://www.airweb.faa.gov/Regulatory...e?OpenFrameSet
The Engine TCDS is the right place for determining *Engine* limits.

I am an FAA certified Mechanic. Officially with only my Airframe license although I'm Working on my powerplant; but I've also rebuilt an O-320 and two IO-360's so far.

I hope this helps you.

[bucaronco]

David,

thanks for confirming that an engine TCDS is, in fact, valid in homebuilts,and for the link. Not exactly the most user friendly one, but maybe I can wade through it.