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  #1  
Old 07-22-2007, 06:05 AM
Aussie 9A Aussie 9A is offline
 
Join Date: Jul 2007
Location: Toowoomba QLD Australia
Posts: 13
Default Engine / prop selection RV-9A

RV-9A Quick build arriving soon. I would like to know has anyone had any experience fitting 180 hp to the RV-9?. I am aware that Van's says that it is a no-no however I believe that it is not an uncommon practice. What are the pro,s & con's? I am considering the ECI Titan IOX 34O and carbon fibre fixed pitch propeller. Has anyone had any experience or comments with this combination?
Next day: Actually the IOX-340 Titan engine (a stroked 320) has a magnesium cold air induction sump and is approx 10lbs lighter than a standard lycoming 320. My thoughts were that with less weight and a little more HP the aircraft may perform similar to a constant speed set up for take off and climb, without the increased capital cost, increased operating cost or increased weight of a c/s unit. In addition the fixed pitch sensenich 70CM aluminum prop (recommended by Van's), has a maximum never exceed speed of 2600 rpm! If this (IOX-340) engine has a weight advantage and a prop is selected that does not have a 2600 rpm restriction (and is lighter) doesn't this combination negate the argument than the nose wheel will be overloaded and the gross weight will be negatively affected. I still realise that the pilot has a responsibility not to exceed the VNE.

Last edited by Aussie 9A : 07-22-2007 at 06:33 PM. Reason: Aditional info
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  #2  
Old 07-22-2007, 08:29 AM
RickWoodall's Avatar
RickWoodall RickWoodall is offline
 
Join Date: Jan 2007
Location: Ontario Canada
Posts: 1,472
Default Why

I have read a pile of threads on this stuff. Just dont understand why you would put in an engine that the kit maker says not to? Yes we are experimental but so what. Need more speed, build a different plane. I am looking for some cool upgrades, but safety is number one, and while newer technology etc is in my plans, some of the tried and true core stuff will be crucial. Good luck, folks have used the 360, but i dont really know why one would do that. You can put a 500hp engine in a minivan, but why? Why not grind down the spars and drill some holes in them to reduce weight too?
Sorry, that was a joke. What are your reasons? Build a 7.
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Rick Woodall C-GSTT "ghost"
9a -TMX io-320, catto three blade, dual dynon hdx with a/p. 900+ hrs in 8 yrs flying.

Flew to Osh 11,12,15,17,19. SNF 2013. West to Cali /Washington/Vancouver/crossed the Rockies north to Red Deer east to Moosonee and over to maritimes. South to Jekyll Isl, cedar key, and Key West etc. 7 trips and 17 islands of the Bahamas. Flown turtles and dogs for Pilots n Paws too. Love our Rv's
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  #3  
Old 07-22-2007, 08:37 AM
Mel's Avatar
Mel Mel is offline
 
Join Date: Mar 2005
Location: Dallas area
Posts: 11,214
Default

I have to agree with Rick. My point is that a larger engine is simply not needed. People continue to argue that "more is better". The RV series of aircraft are so efficient that even with the smallest engines they are MUCH better than anything else flying. I have flown my RV-6, with a tired 150 hp engine and F/P wood prop out of Leadville, CO (density altitude of 13,000') without a problem. The RV-9 performs fantastically with 150 or 160 hp.
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Mel Asberry, DAR since the last century. Over 1,000 certifications accomplished. Discount for Veterans, Law Enforcement, Fire Fighters.
EAA Flight Advisor/Tech Counselor, Friend of the RV-1
Recipient of Tony Bingelis Award and Wright Brothers Master Pilot Award
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RV-6 Flying since 1993 (sold)
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  #4  
Old 07-22-2007, 09:49 AM
rkochcyxh rkochcyxh is offline
 
Join Date: Oct 2005
Posts: 75
Default Cost and weight about the same

I'm really looking at a 0-360 low compression and a fixed pitch prop. About 170hp and the weight is actually about the same or a little less than a 0-3.20 with a c/s prop. Cost is cheaper than the 0-320 with the c/s prop and if needed I can run mogas. Cost of mogas in my neck of the woods is almost $1.75 per gallon cheaper. I think I have my facts about right.
One of the main reasons for the hp restriction is so that you don't exceed the max speed in a 9. If you change you pitch on the prop, you shouldn't exceed the max speed and at the same time increase your rate of climb.
Anyway I think thats the way I'm going. I'm still at least a year or two away from the engine
Russel Koch
QB Wings and Fuse in hanger
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  #5  
Old 07-22-2007, 09:55 AM
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Build9A Build9A is offline
 
Join Date: Jan 2005
Location: Shellmans Bluff, GA
Posts: 517
Default weight on the nose

I think the jury is still out on nosewheel accidents. Could forward weight contribute to the nose fork digging into turf or pavement on a less than perfect landing? If maybe, then why increase the load by putting a bigger, heavier engine up there?

Also, Vans article on the subject of RV9 power plants should be required reading prior to making the 180 hp decision.

I have the 0-320 with a fixed pitch Sensenich. It climbs and cruises as per Vans. Most of my flights are 2 hours or less and a little extra speed would only save me a few minutes.

Good luck on your decision.
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  #6  
Old 07-22-2007, 11:17 AM
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Leland Leland is offline
 
Join Date: Jan 2005
Location: Livermore, California
Posts: 149
Default O320 with a FP way to go

Quote:
Originally Posted by Build9A
I think the jury is still out on nosewheel accidents. Could forward weight contribute to the nose fork digging into turf or pavement on a less than perfect landing? If maybe, then why increase the load by putting a bigger, heavier engine up there?
I agree that a forward C. G. makes it harder to keep the nose wheel off when landing. I have an O320 with a Catto (wood/composite) 3-blade on my 9A and can keep the nosewheel off "forever".

A friend with an RV6A had an O360 with a constant speed prop and bent the nose gear, probably because it was too hard to hold the nosewheel off the runway. He sold the constant-speed prop and installed a Catto. It is now easier to hold the nose off and the plane is faster than it was.

Another friend has an RV6 with a 2-blade Catto and he flies faster than any other 6 on the field, including ones with 200 hp engines.

Light weight on the nose is the way to go.

Leland
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  #7  
Old 07-22-2007, 12:07 PM
rv9builder rv9builder is offline
 
Join Date: Jan 2005
Location: Irvine, CA
Posts: 950
Default

Leland,

Does the Catto prop limit how much weight you can put in the baggage compartment without having the cg move too far aft? Would a Sensenich fixed pitch prop allow you to carry more baggage?

Thanks,
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RV-12iS Fuselage
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  #8  
Old 07-22-2007, 02:54 PM
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N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
Posts: 12,887
Default

Quote:
Originally Posted by rv9builder
Leland,

Does the Catto prop limit how much weight you can put in the baggage compartment without having the cg move too far aft? Would a Sensenich fixed pitch prop allow you to carry more baggage?

Thanks,
Leland,

This might be true for the -7A's but not so much for the -9A's.

What Mel and the others said is true, you are putting 20 more HP in a plane that is already over powered. IMHO, the real limiting factor is GW. With the 20 lbs extra for the O-360 and all the rest, you might find yourself with a plane that can lift two people but no baggage.

The only real advantage the O-360 gives you over the O-320 is ROC and 1,400 FPM from an O-320 is just about rocket ship kind of climb, if you are used to a 172, PA-28, etc. Heck, even with the little O-290 I'm putting in mine, I should see 1,150 FPM and that will still out climb the spam cans.

As Van's once told me, "Build Lightness in."
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RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
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  #9  
Old 07-22-2007, 03:09 PM
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L.Adamson L.Adamson is offline
 
Join Date: Apr 2005
Location: KSLC
Posts: 4,021
Default

Quote:
Originally Posted by Leland

A friend with an RV6A had an O360 with a constant speed prop and bent the nose gear, probably because it was too hard to hold the nosewheel off the runway. He sold the constant-speed prop and installed a Catto. It is now easier to hold the nose off and the plane is faster than it was.
I know too many people with 6A's, 360's and Hartzell C/S props that have no problem keeping the nosewheel up. They just don't read these forums!

The one in the hangar next door just completed it's 11th inspection earilier this month.

However, the 9A, even with just 150HP & a Hartzell C/S prop has plenty of getting up & go power. I was amazed how it could easily head up a canyon near KSLC, where a 172 would require numerous 180 turns for altitude to get over the summit and below Class B airspace.

L.Adamson
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  #10  
Old 07-22-2007, 04:50 PM
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airguy airguy is offline
 
Join Date: Oct 2006
Location: Garden City, Tx
Posts: 5,590
Default

Quote:
Originally Posted by rkochcyxh
. Cost is cheaper than the 0-320 with the c/s prop and if needed I can run mogas. Cost of mogas in my neck of the woods is almost $1.75 per gallon cheaper. I think I have my facts about right.
One of the main reasons for the hp restriction is so that you don't exceed the max speed in a 9.
Bingo. I want to have a nice bit of power in the airplane, and I want to be able to run mogas. Mogas means lower compression, which means a little less power per cubic inch of displacement. The very small weight penalty of a 360 versus a 320 is worth it to me to be able to run Mogas, and I regain the horsepower I lost to low compression by adding a few more cubic inches. Add a fuel injection system with wing-root pumps and some good insulation, and you can keep the vapor-lock gremlins at bay at altitude, as long as you don't run Mogas with ethanol. There are plenty of weight items that can be mounted aft to keep the CG where it needs to be.

I heartily agree with the mantra "Build it light" - you build it light so that you have additional useful load for the things you want to carry. One of the things I choose to carry on every flight is another 20 pounds of engine. Every pound that makes power is a good pound to carry. As for exceeding the Vne - that's a pilot responsibility, not an equipment restriction. You could safely fly a 9A with 600 hp (assuming you can get a usable CG) without exceeding Vne.
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Greg Niehues - SEL, IFR, Repairman Cert.
Garden City, TX VAF 2021 dues paid
N16GN flying 900 hrs and counting; IO360, SDS, WWRV200, Dynon HDX, IFD440, G5
Built an off-plan RV9A with too much fuel and too much HP. Should drop dead any minute now.

Last edited by airguy : 07-22-2007 at 04:57 PM.
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