Too much Horsepower??

N55CU · #1 10-08-2005, 11:57 AM

Since there is not much difference in weight or money between an IO-360 and the new IO-390 (210 hp). Is this way too much for the plane (RV-7). Thanks for any comments!
Randy Utsey
CLT

Bob Axsom · #2 10-08-2005, 01:55 PM

I'm sure going to look at it for my next engine even with all of the additional problems like the need to make a custom cowl for my RV-6A. I can handle the extra work and problem solving but I don't like the fact that it would kick me out of the RV Class in the AirVenture Cup Racing (360 CU. IN. blue sub class limit). I will probably settle for a custom high power rebuild. The only thing that would cause me pause is the amount of fuel you will have on board. I would want a 5 hour fuel burn at 75% power until empty so I could flight plan comfortably for 4 hour legs with and hour reserve. [I have 55 gallons in my plane and burn 10 gph at 75% power]

Bob Axsom

glenmthompson · #3 10-08-2005, 01:55 PM

Quote:

Originally Posted by N55CU

Since there is not much difference in weight or money between an IO-360 and the new IO-390 (210 hp). Is this way too much for the plane (RV-7). Thanks for any comments!
Randy Utsey
CLT

Ok Randy, lets look at it this way. There are MANY 7?s flying around with more HP than you are contemplating. Fire breathing IO 360?s abound, and some are turbo charged. The larger displacement of your 390 IMHO, will prove a long lasting engine with great results. My only concern is that care be taken starting TO roll, so not as to over tax your rudder/feet. GO for it!

osxuser · #4 10-08-2005, 03:15 PM

After looking at prices, if I bought a new engine this would be my ONLY choice. Think about the time TBO comes around, if you still have the airplane, the chances are you could get higher comp. pistons and some tuneing to be pushing close to 250HP.

Fuel burn should be more than an IO-360 due to lower compression and more CI's.

praterdj · #5 10-08-2005, 03:37 PM

I looked at this engine installed in an RV8-A at Oshkosh.

Right now it is my first choice for my RV-8 currently under construction, but the financial factor is a big part of my decision. Not so much with the one time cost of the engine but I am going to have to withhold judgment until after I check with the insurance companies to see what the penalty is for going to 212 horsepower.

Captain_John · #6 10-08-2005, 05:09 PM

I plan on doing it!

Throttling it back to 22 or 23 squared should produce decent economy.

Besides, economy isn't the reason for building a plane!

CJ

gmcjetpilot · #7 10-08-2005, 08:03 PM

Follow van's (airspeed, G's, weight, CG) limitations you will be fine. Can extra HP get you in trouble? Yes, but you have the "get in/out of trouble knob" on the panel (throttle).

What are the specs? I assume it has the same or similar dimensions and weight as an IO360 (200HP). 10 HP is not that much and may be worth 3-4 mph top speed. Climb will be much better of course. G

N55CU · #8 10-10-2005, 06:50 AM

Thanks for the comments. With good fuel flow information I could manage the longer legs but I'm ready for a break anyway at 2 hrs. Sounds like more power "Scotty" is the ticket! For the N.C. area builders, Triad Aviation / www.hhtriad.com / (Burlington, N.C.) is going to offer Lycoming "Experimental" engines in the near future. Our flying club in Charlotte has had good results from all of their engine work.
Best regards,
Randy Utsey
RV-7
Charlotte, N.C.