Whats it going to take to be faster?

[Michael Brown]

As most of you know I am building a 7. I am currently flying a C-150 and I am really tired of my Dad flying circles around me in his 185 hp RV-4 w/ a 3 blade catto. I am planning on a Barret IO-390 with a Hartzell BF CS prop. I am tired of the abuse and have to do whatever it takes to be faster(except put a 540 on the nose). What do you guys think? Thanks in advance.

[N941WR]

Michael,

Start by building it as light as you can.

Go with the electronic ignition of your choice.

Get the rigging right, including the leg, wheel pants, and intersection fairings.

Then work on fairing in anything that sticks out.

[iwannarv]

Also check out a Sam James cowl and plenum to add a few more MPH.

[Michael Brown]

So I do have a challenge after all. I am planning on the james cowl. I know I will be heavier, but I am building it as clean as possible. I will post the results in a couple years when I finish building.

[RV7Guy]

Build it clean and light. Also consider the Whirlwind 200RV prop. It is 35lbs lighter than the Hartzell and was designed for the RV airframe. It is extremely smooth and light.

[SteelMike]

Unless I've missed something, I haven't seen a lot of action on the 390 engines or people's experiences with them. I'll be very interested to hear how it goes if you head that direction. I've been sternly directed by a buddy who's just finishing an 8 ("no, really, you should really check out the 390. Really."), and it is a pretty compelling solution, even if you save money by going with a fixed pitch prop.

More "power" to ya (dumb pun intended). Let us know how it goes.

[Transporter]

We have three Barrett IO-390 RVs in the local area (that I know of); one RV7 (flying, with CS Prop), one RV7A (panel is done, working on FWF), and one RV8 (almost ready for first flight).

I've flown the RV7...and it's an incredible ride. Leaps tall buildings. Faster than...well you get the idea.

Search the forums using "IO-390" and you'll pull up quite a few references.

Mike

[Dayton Murdock]

FASTER = MONEY!

[rtry9a]

Originally Posted by Dayton Murdock

FASTER = MONEY!

Only when you make the wrong choice up front.

Seriously, it is easier to get more speed by reducing drag than by increasing hp.

If you want significantly more power, a turbocharged rotary is the way to go- it is good for 350-400 hp with minimal weight penalty (compared to a IO-360/390) and will cost a whole lot less, maybe half (in the $10K range). Base engine approx $2K, weighs ~200 lbs. with flywheel. Dont use OEM automotive turbo.

A naturally aspired 6-port Renesis engine (or a peripheral ported older 13B) is good for 250-270 hp with a tuned intake. It will not require limiting power, due to heat, at full throttle.

[breister]

Don't know which rotary specifically you are referring to, have heard varying reports of success there.

Looks like Rotamax just lost one of their test designs - click here.