Performance Tables for 74 P337 vs Riley Super SkyRocket
 

I have taken the book figures to make a couple of Excel spreadsheets for performance tables comparing a 1974 T337G to Riley's Super SkyRocket conversion with the TSIO520's. The book figures only show MPH and LBs of fuel burned and total range exhausting fuel (which is a misleading figure). These tables add Knots, gallons per hour and range with 45 minute and 1 hour reserves. The 74 SkyMaster carried 123 gallons/738 lbs while the Super SkyRocket carries 148 usable/888 lbs.

I turned the excel files into pdf files since they didn't want to upload.

Curious, why the choice of 2200 RPM?

2200 rpm is the max continuous rpm after initial takeoff and climb as well as cruise in the Riley Super SkyRocket. I know... interesting.

Learn something new everyday!

Interesting, thanks. The P337 values are very similar to what I've experienced with my '73 P337 so far. The Rocket seems to have a significantly increased fuel burn for a modest increase in speed. I guess one other factor is it gets up to altitude quicker.

DD

The STC only allows full power, which is 300 hp, not 310 like the same engine in 340. 38"@2,600rpm for 2 minutes. Then 34"@2200rpm for max continuous (which ironically is 225 hp). The other interesting factor I discovered is the AD for the engine back in 2009 instructing to NOT operate at rpm's below 2,300 for cruise. If I can get a chance to talk to a Super SkyRocket pilot I can ask if they use something other than the 2,200 which the Riley POH calls for.

The stock numbers look Cessna (optimistic) numbers that are not real most of the time. Mine doesn't do those numbers. The super skyrocket numbers look like they factor in real world preformance.

Using 10,000 feet and fuel flow as closest as they come. that is the highest power setting on the stock engines, the lowest on the skyrocket and they still have about almost a 2 GPH spread with the skyrocket burning more.

Stock it does 184kts and the skyrocket does 168kts. I dont buy that it burns about 2 GPH more and goes 16 knots slower. I am sure it is heavier and has more cooling drag but 16 knots slower on 2 more GPH of fuel?