RV-6a vs RV-8 speed

Ron Lee · #1 09-05-2009, 07:31 AM

Yesterday on the way to Creede Colorado a RV-8 pilot and I decided to check actual speeds side by side....full throttle/best speed possible. We were at 12,500' I believe. There may have been around a 10 knot tailwind component but using GPS groundspeed I reported 176 knots and he reported 177 knots.

So considering the short run and data collection inaccuracies, we were essentially the same speed.

I think both engines are O-360 but I have 9.2:1 pistons, flow matched carbureted engine and FP prop (Catto three blade). His engine is 200 HP and with my improvements mine may approach that.

He has a 3 blade MT prop. (correction from initial erroneous Hartzell prop statement)

I have one Lightspeed ignition and he has two.

Kevin Horton · #2 09-05-2009, 10:14 AM

Quote:

Originally Posted by Ron Lee

Yesterday on the way to Creede Colorado a RV-8 pilot and I decided to check actual speeds side by side....full throttle/best speed possible. We were at 12,500' I believe. There may have been around a 10 knot tailwind component but using GPS groundspeed I reported 176 knots and he reported 177 knots.

So considering the short run and data collection inaccuracies, we were essentially the same speed.

I think both engines are O-360 but I have 9.2:1 pistons, flow matched carbureted engine and FP prop (Catto three blade).

He has a Hartzell prop.

I have one Lightspeed ignition and he has two.

What rpm did you have, and does he have an older Hartzell with 7666 blades, or one of the newer blended airfoil Hartzells?

Bob Axsom · #3 09-05-2009, 11:07 AM

Right now it looks like there are three of you in the RV Blue Class in the Pagosa Springs, Colorado race later this month (www.sportairrace.org calendar of events), an RV-8, an RV-6 and you in the RV-6A. The other guys are fast but you can bet I'm pulling for you to show them up (sorry John and Mike). The RV-6A is a lot faster than it is given credit for.

Bob Axsom

Ron Lee · #4 09-05-2009, 11:56 AM

I do not recall my RPM but will do it again in the near future and report it. I will ask about his (RV-8) blades. (it is a 3 blade MT prop...corrected first post).

Bob, if John Huft is running he will be on the ground eating lunch before I finish.

Bob Axsom · #5 09-05-2009, 12:44 PM

John Huft is in with his Super Fast RV-8 and Mike Thompson is no slouch in his RV-6 either. You can shoot for beating your Memphis speed. When I run the course I am so engrossed in flying as straight and level and fast as I can making all of the turns correctly with required approach calls and my senses peaked with the exhilaration of the moment that how I finish is almost (not quite) an afterthought. I really like to finish above 210 mph if I can but above 200 mph is OK. Before all the mods those standards were 190 and 180 mph respectively. Enjoy the race and do the RV-6As proud.

Bob Axsom

Kevin Horton · #6 09-05-2009, 03:04 PM

Quote:

Originally Posted by Ron Lee

I will ask about his (RV-8) blades. (it is a 3 blade MT prop...corrected first post).

Ask him for the full prop model number, if he can find it. The older MTs were known to be quite slow. Recently, they came out with a new blade (model number ends in "-59b"), and some folks claim it is quite a bit faster than the older one.