What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Engine / prop selection RV-9A

Aussie 9A

Member
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:
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.
 
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.
 
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
 
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.
 
O320 with a FP way to go

Build9A said:
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
 
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,
 
rv9builder said:
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."
 
Leland said:
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! :D

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
 
rkochcyxh said:
. 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.
 
Last edited:
When selecting an engine for your plane it is wise to listen to the kit manufacturer and those that are already flying. Not to those that are building and don't really know what they are talking about.
 
Norman CYYJ said:
When selecting an engine for your plane it is wise to listen to the kit manufacturer and those that are already flying. Not to those that are building and don't really know what they are talking about.

Some SERIOUS assumptions being made here.... :rolleyes:
 
I am not looking for speed. See my edited additional info posted today. I wondered if this combination would give better take-off and climb performance without the extra weight, cost or maintenance of a c/s unit. Also note that not only is there no additional weight there is actually a weight saving.
 
baggage limiting weight

rv9builder said:
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,
In my Catto pulled 9A, a pilot and passenger weighting a total of 400 pounds limits baggage to 60 pounds if the fuel tanks are completely empty. Eleven gallons of fuel allows 75 pounds of baggage. As base weight, my baggage compartment contains oxygen, an ELT and the strobe power supply. Take a look at Checkoway's site for more W&B examples: http://www.rvproject.com/wab/ .
Leland
 
L.Adamson said:
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! :D
The one in the hangar next door just completed it's 11th inspection earilier this month.
L.Adamson

L.
Agreed, most RV A models have never had a problem with nose-over. But there are quite a few that have, for example see http://www.ntsb.gov/publictn/2006/RV_Photos.pdf . The NTSB analysis shows that increasing the weight on the nose increases the dynamic load and reduces clearance. It's true, most nose-overs happen on rough strips. But I have seen and exerienced nose wheel "twang" for improper landings on good paved strips.

More weight on the nose reduces your safety factor. Besides, it's a wonderful feeling to have full elevator authority until almost ready to turn off the runway.
Leland
 
Hummm...

airguy said:
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.

.

Just curious, does Mogas have less energy density then 100LL?
If so then add less range on the 36 gal of fuel that you are packing.

As for weight and balance. The only way to get my plane out of CG is to put 120 lb in the baggage, 450 lb for pilot and passenger and only 5 gal of fuel.
I only allow 100 lb in the baggage and so will never go aft CG. I can't go forward CG and still have a pilot, unless you can find one that weights less the 60 lbs.

Kent
 
kentb said:
Just curious, does Mogas have less energy density then 100LL?
If so then add less range on the 36 gal of fuel that you are packing.
No, the higher octane the less energy. There was an article on this in either AOPA or EAA a few years back.

For details check out this Wikipedia entry.

Wikipedia said:
Higher octane ratings correlate to higher activation energies. Activation energy is the amount of energy necessary to start a chemical reaction. Since higher octane fuels have higher activation energies, it is less likely that a given compression will cause knocking. (Note that it is the absolute pressure (compression) in the combustion chamber which is important - not the compression ratio. The compression ratio only governs the maximum compression that can be achieved).

Octane rating has no direct impact on the deflagration (burn) of the air/fuel mixture in the combustion chamber. Other properties of gasoline and engine design account for the manner at which deflagration takes place. In other words, the flame speed of a normally ignited mixture is not directly connected to octane rating. Deflagration is the type of combustion that constitues the normal burn. Detonation is a different type of combustion and this is to be avoided in spark ignited gasoline engines. Octane rating is a measure of detonation resistance, not deflagration characteristics.

It might seem odd that fuels with higher octane ratings explode less easily, yet are popularly thought of as more powerful. The misunderstanding is caused by confusing the ability of the fuel to resist compression detonation as opposed to the ability of the fuel to burn (combustion). However, premium grades of petrol often contain more energy per litre[citation needed] due to the composition of the fuel as well as increased octane.
 
180 HP

I was undecided at first on what engine i wanted in a 9A, so i looked at all of Van's warnings,spoke to a couple owners who had the 180's and examined my needs at a high altitude airport ( 5000') and then spoke with an individual who knew Van,s brother, Jerry. He told my friend that there have never been any flutter tests on the 9A and that the concerns about using the 180 are based soley on the longer wing maybe notbeing able to handle the same loads as the other series of RVs I also spoke with many people with much more knowlege then I have and asked them about TAS vs IAS. All said that structural load limitations are based on IAS and that flutter was a result of the velocity of air going over the airframe which relates to TAS. However since Number 1, there have never been any flutter tests on the plane and 2, with a normal aspirated engine it would be nearly impossible to get a TAS of VNE except in a dive and even harder to get an IAS of VNE ( and one could get a 160 HP model past VNE in a dive just about as easlily), all ageed that 180 would be a good choice for a plane that was being normally operated in high density altitudes. They all cautioned that one should be aware of the yellow line as with 180 it would be slightly easier, note, just slightly easier, to get in that range then with 160HP The bottom line was that with out any flutter tests to provide impirical data, Van's warnings are very conservative and that there may be situations where it would be preferable to have 180HP. As others have said power and speed management are up to the pilot. As for there being too much weight on the nose, I do not give that argument any credence, unles one is planning on landing nose first. My 9A with the Titan 180 HP and the Hartzel blended airfoil CP and well equipted with state of the art radios and AP weighs 1095#,and I have had no issues with a heavy nose or W&B And while i am aware that many say 160 is more than enough and that one owner flies out of Leadville with 150. I will bet that when he flies off that airport with a 13000 ' density as he claims, that he is very light and either way would be happier with 180. I say there is no substitute for horse power in some situations. And flying off a 13000 ' altitude airport sounds like the prime example of one of those situations. With the 180, I can throttle back and get the same fuel economy as with 160 and work the engine a bit less. So for me 180 was a win win. Incidently I have tried in vain to get Van's to provide any load testing results but have always been denied that info because it is propietary. I think that Van is simply protecting himself against potential claims with his warnings against 180 horse power. And with the times we live in, i can not blame him. But why he claims that flutter is the problem when there have been not tests or reports of flutter is a mystery to me. I doubt that any of Van's planes have ever undergone any tests for flutter. Does anyone know of any documented tests? Maybe there is one case ot it occurring at around 240 IAS in a 4 with no damage, but anything else?
 
How efficient is it to use a throttled back 180Hp instead of a 150/60 which is working at it's optimum throttle setting ? I can see some of the arguements for larger engines - however as Vans designed her to take a maximum of 160HP - why not just go down the RV-7 route instead?
 
Aussie 9a,

You asked for input from anyone who has "experience fitting 180 hp to an RV-9(a)". I did just that and have been happily flying that airplane since March of last year. Many of the reasons for the selection of that engine parrallel those of Questair. The following is a summary of the features that we wanted in an aircraft along with the factors that lead to my engine/prop selection;

I wanted a two place airplane that was a stable IFR capable cross country flyer (no interest in aerobatics) so I selected the 9a. I wanted simple operation as my wife intends to finish up her private pilot training in the plane. However, it needed to have excellent take off performance as we will be living in N. Az. where afternoon summertime density altitudes are frequently challenging. I also wanted to keep costs down (who doesn't), wt down, and select an engine/prop combo which provided smooth/quiet operation on long x-c flights.

I boiled my options down to a 9a with an 0320 and a Hartzell cs (Vans recommendation) or a 9a with an 0360 and a Catto 3 blade composite fp.

Cost: The difference in cost of a new experimental 0320 vs 0360 at Vans or Americas Aircraft Engines (ECi) is $500--I suspect Mattituck and Superior are similar differentials.
The cost of a new Hartzell plus governor is around $7K (at the time I was shopping) while a Catto 3 bade with the Sabre spacer is $2K. The cost of the 360/Catto is therefore $4500 less than the 0320/Hartzell.

Weight: The weight difference between the 0320 and the 0360 per Lycomings certificated weight tables averages less than 10 lbs. The difference in wt between the specific 0320 model Vans sells(D1A) and the specific model 0360 they sell (A1A) is less than 6 lbs.
The Hartzell CS with governor totals around 60 lbs. while the Catto plus spacer weighs in at 20 lbs. Using the 10 lbs engine wt differential, the weight of the 360/Catto is therefore around 35 lbs lighter than the 320/Hartzell.

Performance: Although I have never tested this, I suspect that the 0320 with the CS prop will climb better than my fp 0360 but my guess is that the difference is small.
The crusie performance of the 0360/Catto is better than the 0320/Hartzell if you want to use 75% power numbers---if you cruise the 0360 at 65-67% you will see close to the same performance in cruise/ff as the 0320 running at 75% while creating less noise and putting less stress on the engine.

I fly this plane at 66-67% power (seems to have a sweet spot there) per the Lyc chart and see performance #s that exceed Vans published 75% 0320/CS numbers (probably due to the James cowl/plenum). Additionally at these relatively low power settings the engine/3 blade composite prop combo is extremely smooth and with the slower prop tip speeds it is also relatively quiet.

Downside: If you elect to fly at 75% power you will not be able to hit Vne in level flight at altitude (with a stock 180 hp) but you will be closer than a 320 9a and must therefore be careful when transitioning from cruise to descent--although any RV will quickly pick up speed in descent if the power is not managed correctly.

Given the options would I do it again? Lets see: over $4000 less cost, 35 lbs less wt, better cruise capability, similar climb capability, less engine stress, lower noise, less complexity/maintenance, and smooth operation-----yea, faced with the same two options I would most likely do it again.

Cheers,

db
 
I'm willing to give up a hair of efficiency (the pumping loss differential of a 360 vs a 320, given the same hp output) in the interest of effectively running a "derated" engine in cruise. I want the excess power available in the event I need it - just because it's there doesn't mean I have to use it. Hot, high and heavy, it will save your bacon. Light and cool you just pull back a bit and see very nearly the same BSFC you would with a 320. I come in and out of Albuquerque often enough to know a thing or two about density altitude, and I want the spare power.

As for mogas having less energy density - it's a small enough margin that's it basically negligible, but I believe the previous comment about 100LL being slightly lower is correct. In any case, my typical mission is 500-700 nm solo business trips, so I'll be running the Safeair Whiskey Hotel extended range tanks. That decision was made quite a while back, along with the engine choice. Solo trips with only a laptop and two days worth of clothes do not present a weight issue - I'd rather carry the additional fuel with my spare useful load. The cruise speed differential between light load and gross load in a 9A is only 1 mph according to Van himself, so I cannot think of a valid argument for not carrying the fuel if I don't need the additional useful load for something else. A speed reduction of 1 mph in cruise buys me an extra 1:30 airborne at conservative power settings, which could end up saving your bacon one day in weather.

As db1yg was saying, the cost and weight differential between the two engines is minimal. FP versus CS prop issue is a whole 'nuther animal, but I have decided to run a constant-speed prop on mine. I haven't pinned down the prop yet, but I'm leaning toward a Hartzell BA. This will give me greater efficiency at high altitude where I like to cruise, let me maximize my horsepower on hot takeoffs in the desert, and the speed penalty for carrying an extra 40 pounds in the 9A is minimal, as I've already touched on. I'll pick a good-sized battery (instead of just barely enough) and mount it way back in the tail to keep the CG under control with the extra weight of the engine and prop up there.

I'm not building a racer, I'm not building an "ultimate efficiency" machine, I'm not interested in aerobatics - I just want my private version of Southwest Airlines for my business travel. This gets me close.
 
Last edited:
db1yg said:
Aussie 9a,

You asked for input from anyone who has "experience fitting 180 hp to an RV-9(a)". I did just that and have been happily flying that airplane since March of last year. Many of the reasons for the selection of that engine parrallel those of Questair. The following is a summary of the features that we wanted in an aircraft along with the factors that lead to my engine/prop selection;

I wanted a two place airplane that was a stable IFR capable cross country flyer (no interest in aerobatics) so I selected the 9a. I wanted simple operation as my wife intends to finish up her private pilot training in the plane. However, it needed to have excellent take off performance as we will be living in N. Az. where afternoon summertime density altitudes are frequently challenging. I also wanted to keep costs down (who doesn't), wt down, and select an engine/prop combo which provided smooth/quiet operation on long x-c flights.

I boiled my options down to a 9a with an 0320 and a Hartzell cs (Vans recommendation) or a 9a with an 0360 and a Catto 3 blade composite fp.

Cost: The difference in cost of a new experimental 0320 vs 0360 at Vans or Americas Aircraft Engines (ECi) is $500--I suspect Mattituck and Superior are similar differentials.
The cost of a new Hartzell plus governor is around $7K (at the time I was shopping) while a Catto 3 bade with the Sabre spacer is $2K. The cost of the 360/Catto is therefore $4500 less than the 0320/Hartzell.

Weight: The weight difference between the 0320 and the 0360 per Lycomings certificated weight tables averages less than 10 lbs. The difference in wt between the specific 0320 model Vans sells(D1A) and the specific model 0360 they sell (A1A) is less than 6 lbs.
The Hartzell CS with governor totals around 60 lbs. while the Catto plus spacer weighs in at 20 lbs. Using the 10 lbs engine wt differential, the weight of the 360/Catto is therefore around 35 lbs lighter than the 320/Hartzell.

Performance: Although I have never tested this, I suspect that the 0320 with the CS prop will climb better than my fp 0360 but my guess is that the difference is small.
The crusie performance of the 0360/Catto is better than the 0320/Hartzell if you want to use 75% power numbers---if you cruise the 0360 at 65-67% you will see close to the same performance in cruise/ff as the 0320 running at 75% while creating less noise and putting less stress on the engine.

I fly this plane at 66-67% power (seems to have a sweet spot there) per the Lyc chart and see performance #s that exceed Vans published 75% 0320/CS numbers (probably due to the James cowl/plenum). Additionally at these relatively low power settings the engine/3 blade composite prop combo is extremely smooth and with the slower prop tip speeds it is also relatively quiet.

Downside: If you elect to fly at 75% power you will not be able to hit Vne in level flight at altitude (with a stock 180 hp) but you will be closer than a 320 9a and must therefore be careful when transitioning from cruise to descent--although any RV will quickly pick up speed in descent if the power is not managed correctly.

Given the options would I do it again? Lets see: over $4000 less cost, 35 lbs less wt, better cruise capability, similar climb capability, less engine stress, lower noise, less complexity/maintenance, and smooth operation-----yea, faced with the same two options I would most likely do it again.

Cheers,

db
I have noticed that many people are saying that one of the advantages of a c/s prop is that it provides significant breaking when needed. What are the characteristics of the 3 blade catto in this regard say as compared to a two blade f/p prop?
 
db1yg said:
Aussie 9a,

You asked for input from anyone who has "experience fitting 180 hp to an RV-9(a)". I did just that and have been happily flying that airplane since March of last year. Many of the reasons for the selection of that engine parrallel those of Questair. The following is a summary of the features that we wanted in an aircraft along with the factors that lead to my engine/prop selection;

I wanted a two place airplane that was a stable IFR capable cross country flyer (no interest in aerobatics) so I selected the 9a. I wanted simple operation as my wife intends to finish up her private pilot training in the plane. However, it needed to have excellent take off performance as we will be living in N. Az. where afternoon summertime density altitudes are frequently challenging. I also wanted to keep costs down (who doesn't), wt down, and select an engine/prop combo which provided smooth/quiet operation on long x-c flights.

I boiled my options down to a 9a with an 0320 and a Hartzell cs (Vans recommendation) or a 9a with an 0360 and a Catto 3 blade composite fp.

Cost: The difference in cost of a new experimental 0320 vs 0360 at Vans or Americas Aircraft Engines (ECi) is $500--I suspect Mattituck and Superior are similar differentials.
The cost of a new Hartzell plus governor is around $7K (at the time I was shopping) while a Catto 3 bade with the Sabre spacer is $2K. The cost of the 360/Catto is therefore $4500 less than the 0320/Hartzell.

Weight: The weight difference between the 0320 and the 0360 per Lycomings certificated weight tables averages less than 10 lbs. The difference in wt between the specific 0320 model Vans sells(D1A) and the specific model 0360 they sell (A1A) is less than 6 lbs.
The Hartzell CS with governor totals around 60 lbs. while the Catto plus spacer weighs in at 20 lbs. Using the 10 lbs engine wt differential, the weight of the 360/Catto is therefore around 35 lbs lighter than the 320/Hartzell.

Performance: Although I have never tested this, I suspect that the 0320 with the CS prop will climb better than my fp 0360 but my guess is that the difference is small.
The crusie performance of the 0360/Catto is better than the 0320/Hartzell if you want to use 75% power numbers---if you cruise the 0360 at 65-67% you will see close to the same performance in cruise/ff as the 0320 running at 75% while creating less noise and putting less stress on the engine.

I fly this plane at 66-67% power (seems to have a sweet spot there) per the Lyc chart and see performance #s that exceed Vans published 75% 0320/CS numbers (probably due to the James cowl/plenum). Additionally at these relatively low power settings the engine/3 blade composite prop combo is extremely smooth and with the slower prop tip speeds it is also relatively quiet.

Downside: If you elect to fly at 75% power you will not be able to hit Vne in level flight at altitude (with a stock 180 hp) but you will be closer than a 320 9a and must therefore be careful when transitioning from cruise to descent--although any RV will quickly pick up speed in descent if the power is not managed correctly.

Given the options would I do it again? Lets see: over $4000 less cost, 35 lbs less wt, better cruise capability, similar climb capability, less engine stress, lower noise, less complexity/maintenance, and smooth operation-----yea, faced with the same two options I would most likely do it again.

Cheers,

db
Thanks for the info - What is a James cowl/plenum?
 
Aussie 9A said:
I have noticed that many people are saying that one of the advantages of a c/s prop is that it provides significant breaking when needed. What are the characteristics of the 3 blade catto in this regard say as compared to a two blade f/p prop?
In answer to your question, the 3-blade prop requires more effort to slow the airplane down because with a reduced diameter you have less disk area (drag). But be aware that the constant speed prop does not allow the airplane to fly slower, it's just easier to slow down. Once you get used to YOUR prop it's not a problem to slow down. Each and every airplane is different. You have to learn yours.
 
questair said:
I was undecided at first on what engine i wanted in a 9A, so i looked at all of Van's warnings,spoke to a couple owners who had the 180's and examined my needs at a high altitude airport ( 5000') and then spoke with an individual who knew Van,s brother, Jerry. He told my friend that there have never been any flutter tests on the 9A and that the concerns about using the 180 are based soley on the longer wing maybe notbeing able to handle the same loads as the other series of RVs I also spoke with many people with much more knowlege then I have and asked them about TAS vs IAS. All said that structural load limitations are based on IAS and that flutter was a result of the velocity of air going over the airframe which relates to TAS. However since Number 1, there have never been any flutter tests on the plane and 2, with a normal aspirated engine it would be nearly impossible to get a TAS of VNE except in a dive and even harder to get an IAS of VNE ( and one could get a 160 HP model past VNE in a dive just about as easlily), all ageed that 180 would be a good choice for a plane that was being normally operated in high density altitudes. They all cautioned that one should be aware of the yellow line as with 180 it would be slightly easier, note, just slightly easier, to get in that range then with 160HP The bottom line was that with out any flutter tests to provide impirical data, Van's warnings are very conservative and that there may be situations where it would be preferable to have 180HP. As others have said power and speed management are up to the pilot. As for there being too much weight on the nose, I do not give that argument any credence, unles one is planning on landing nose first. My 9A with the Titan 180 HP and the Hartzel blended airfoil CP and well equipted with state of the art radios and AP weighs 1095#,and I have had no issues with a heavy nose or W&B And while i am aware that many say 160 is more than enough and that one owner flies out of Leadville with 150. I will bet that when he flies off that airport with a 13000 ' density as he claims, that he is very light and either way would be happier with 180. I say there is no substitute for horse power in some situations. And flying off a 13000 ' altitude airport sounds like the prime example of one of those situations. With the 180, I can throttle back and get the same fuel economy as with 160 and work the engine a bit less. So for me 180 was a win win. Incidently I have tried in vain to get Van's to provide any load testing results but have always been denied that info because it is propietary. I think that Van is simply protecting himself against potential claims with his warnings against 180 horse power. And with the times we live in, i can not blame him. But why he claims that flutter is the problem when there have been not tests or reports of flutter is a mystery to me. I doubt that any of Van's planes have ever undergone any tests for flutter. Does anyone know of any documented tests? Maybe there is one case ot it occurring at around 240 IAS in a 4 with no damage, but anything else?
Appreciate your long response. Are you using the IOX-340 Titan or the 360 (carb or F/I)? Are you happy with the ECI Titan Brand and here did you purchase same?
 
Aussie9a,

Mel has provided a good answer to your question on the braking characteristics of the fp 3 blade Catto. I would add that it took little very little time adjusting to this characteristic (lack of braking).

Reference the James cowl/plenum--you have probably seen RV cowls with round vs oval openings for the cooling inlets--these were probably James cowls. James Aircraft of Florida makes cowls and plenum cooling chambers that reduce cooling drag when compared with the stock setup. You can find their web site by searching for James Aircraft.

Best Wishes with your 9! Whatever decisions you make relative to engine/prop/cowl you are going to love the honest/simple flight characteristics of this airplane!!!!

Cheers,

db
 
I have one

quote........"I have noticed that many people are saying that one of the advantages of a c/s prop is that it provides significant breaking when needed. What are the characteristics of the 3 blade catto in this regard say as compared to a two blade f/p prop?"

Hi Oz,
My three-bladed Catto gets a lot of praise for its being so quiet, both in the cockpit and for folks below. I give a bunch of transition training to students with anywhere from 70 hours total time to several thousand. They've all mastered slowing down within a couple of hours at the most. Slowing dow, as Mel points out, is a no-brainer, just pull the power back. However, if you come charging into the pattern at 185 MPH (as we sometimes do to show off :D ), then you're going to go a couple of miles past the airport to get down to flap speed. In my -6A, 2000 RPM=, 140MPH, a good max pattern speed and 1750 RPM=110 MPH with two aboard, also a good number for instrument approaches. Once you learn your RPM/airspeed relationships, it'll be easy to put the speed exactly where you want it.
I'm not sure how my prop compares to a two blade but there is a significant amount of ground clearance...a good thing on dirt/grass strips.
Regards,
Pierre
 
Mel,

How does the Catto prop do in rain? Do you fly IFR wth it? Is it as good as an MT in this regard?
 
Hmmmm.....

[fictional conversation with self] :D

A: RV9(A) O-320 FP prop fly very well according to everyone flying one.

I: I want better performance on takeoff at HD alt.
A: Well I could go to a CS prop and then I will be able to optimize for takeoff and cruse.

I: I want to be able to fly next to VNE at all alt.
A: Well I could put 180hp in instead of 160hp it only adds a few pounds which I will make up for by switching to a FP prop.

I: I can't optimize my takeoff and cruse performance any more.
A: Well I'll just put the CS prop back on, it only adds a few more pounds.

I: I want more range then I am getting when I run the engine/plane fast.
A: Well I'll just add some extended range tanks. It will only add a few pounds. It is a good thing that I put the bigger engine in.

I: I want to save money on all the extra fuel that I am buying.
A: Well, I can switch to Mogas. It is cheaper and will work with my engine. All I need to do to overcome some of its problems is add extra insulation and pumps and pluming, just a few more pounds.

I: Weight and Balance seems to be a little bit of an issue.
A: I'll move the battery back and use a bigger one. It will only add a few pounds.

I: My landing gear / tires seem to be taking a beating.
A: Well guess I will switch to the bigger gear legs and tires that are shipped with the RV10. It will add a few pounds, but I won't need to worry about hard landings.

[conversation fades away] ;)

I am sorry if it looks like I am picking on anyone, that is not my intention, it is just I can't take it any more and have to speak-up. Yes these are experimental airplanes (although I look at them more as kit planes), and you are free to change anything that you want. It is just that if the plane is so far from what you want, why not start with a different plane? :confused:

Kent
 
Last edited:
RV-9A with the Stroker engine

Aussie 9A said:
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.

I'm looking at doing exactly the same thing. I'm sorry to see the replies but clearly they're from folks that either have not thought through what you're doing or just don't understand what experimental is all about. Now on to your questions and to add a couple of comments.

I have not flown a 9A with 180hp Lycoming in it. However, I'd urge you to call Richard at Amaerica's Aircraft Engines and I'm sure he can put you in contact with plenty of folks who are flying a 9A with the 180hp (and more).

In my assessment, weight of the O-360 Lycoming is a bigger deal than the extra power. You'll need to manage the power but it's apparent you've figured that out. With the EFIS units available today you can set your limits, program an alarm and there's no need for a problem to occur - even if you're distracted momentarily. The fact is, you can observe Van's weight and speed limits and have the extra power when you want it (even if you don't need it). I'm yet to meet a pilot whose skills I admire tell me he ever flew a plane that had too much power. The Stroker engine gives you the extra power without the extra weight and going with the carbon fiber prop will give you about a 30lbs advantage over what the CS Van recommends weighs. My choice is the Whirlwind 200RV; what are you looking at hanging up front?

Pay attention to the dimensions of that cold sump by ECI. It forces you to use the snorkel cowl, which from everyone I've spoken to is not fun. I believe Tom Green's comment was "It isn't plug and play with the snorkel cowl."(spoken with his dry wit). I've decided to go with the hot sump and use the Silver Hawk FI system and avoid the return lines. I can then use the 180hp cowl with the scoop.

I used ask for comment here but I no longer have the patience to wade through the plethora of folks that seem to already know the answer is whatever Van said it was. It's a shame because this forum used to be pretty good for bouncing ideas around. Instead, I mostly keep my own counsel - it limits me to my creativity and technical expertise rather than exercising the same with other like minded individuals and gaining more insight. Feel free to email me directly if you'd like.

Don

www.propjock.com
 
titan 0-360

Aussie 9 I have the 0-360 Titan (carb version) do not know from whom purchased. Mags and it starts very easily hot or cold. Some injected 360's are often troublesome starting when hot. Still interested in hearing about any flutter problems. Can understand Van's fear of lawyers, but why is he concerned about flutter on the 9, having done no tests, but does not seem to address the issue with the other models.
 
I guess that I am confused...

questair said:
Still interested in hearing about any flutter problems. Can understand Van's fear of lawyers, but why is he concerned about flutter on the 9, having done no tests, but does not seem to address the issue with the other models.

I thought that the engineers on a plane (not just the RV9) would do some kind of analysis on the design and would predict that flutter would occur at some air speed (where the flutter would be could change at different speeds).
The the plane would be flown as some speed below that flutter speed (80%??) to make sure that the plane would not fly apart. I can't imagine that anyone would fly the plane to the flutter speed, just to verify that the tail would fall off as expected. :eek:

Is there something that I am not understanding?

If this is correct and Vans didn't fly the (80%?) test, then until someone else does so, I'll feel safer by just following what the engineers said was safe.

Kent
 
Don said:
I'm looking at doing exactly the same thing. I'm sorry to see the replies but clearly they're from folks that either have not thought through what you're doing or just don't understand what experimental is all about. Now on to your questions and to add a couple of comments.

I have not flown a 9A with 180hp Lycoming in it. However, I'd urge you to call Richard at Amaerica's Aircraft Engines and I'm sure he can put you in contact with plenty of folks who are flying a 9A with the 180hp (and more).

In my assessment, weight of the O-360 Lycoming is a bigger deal than the extra power. You'll need to manage the power but it's apparent you've figured that out. With the EFIS units available today you can set your limits, program an alarm and there's no need for a problem to occur - even if you're distracted momentarily. The fact is, you can observe Van's weight and speed limits and have the extra power when you want it (even if you don't need it). I'm yet to meet a pilot whose skills I admire tell me he ever flew a plane that had too much power. The Stroker engine gives you the extra power without the extra weight and going with the carbon fiber prop will give you about a 30lbs advantage over what the CS Van recommends weighs. My choice is the Whirlwind 200RV; what are you looking at hanging up front?

Pay attention to the dimensions of that cold sump by ECI. It forces you to use the snorkel cowl, which from everyone I've spoken to is not fun. I believe Tom Green's comment was "It isn't plug and play with the snorkel cowl."(spoken with his dry wit). I've decided to go with the hot sump and use the Silver Hawk FI system and avoid the return lines. I can then use the 180hp cowl with the scoop.

I used ask for comment here but I no longer have the patience to wade through the plethora of folks that seem to already know the answer is whatever Van said it was. It's a shame because this forum used to be pretty good for bouncing ideas around. Instead, I mostly keep my own counsel - it limits me to my creativity and technical expertise rather than exercising the same with other like minded individuals and gaining more insight. Feel free to email me directly if you'd like.

Don

www.propjock.com

Your comments greatly appreciated. I am considering a Prince or Catto prop. As far as the extra HP/speed is concerned, my opinion is that the prop selection would have the most impact on outright speed and not HP. For example if you select a prop that suits 160 HP engine then the WOT speed at 2700 rpm would be the same irrespective of the available HP behind it. The big advantage would be on take off where you would have a higher static RPM. Does anyone agree?

Regards. Fred
 
kentb said:
[fictional conversation with self] :D

A: RV9(A) O-320 FP prop fly very well according to everyone flying one.

I: I want better performance on takeoff at HD alt.
A: Well I could go to a CS prop and then I will be able to optimize for takeoff and cruse.

I: I want to be able to fly next to VNE at all alt.
A: Well I could put 180hp in instead of 160hp it only adds a few pounds which I will make up for by switching to a FP prop.

I: I can't optimize my takeoff and cruse performance any more.
A: Well I'll just put the CS prop back on, it only adds a few more pounds.

I: I want more range then I am getting when I run the engine/plane fast.
A: Well I'll just add some extended range tanks. It will only add a few pounds. It is a good thing that I put the bigger engine in.

I: I want to save money on all the extra fuel that I am buying.
A: Well, I can switch to Mogas. It is cheaper and will work with my engine. All I need to do to overcome some of its problems is add extra insulation and pumps and pluming, just a few more pounds.

I: Weight and Balance seems to be a little bit of an issue.
A: I'll move the battery back and use a bigger one. It will only add a few pounds.

I: My landing gear / tires seem to be taking a beating.
A: Well guess I will switch to the bigger gear legs and tires that are shipped with the RV10. It will add a few pounds, but I won't need to worry about hard landings.

[conversation fades away] ;)

I am sorry if it looks like I am picking on anyone, that is not my intention, it is just I can't take it any more and have to speak-up. Yes these are experimental airplanes (although I look at them more as kit planes), and you are free to change anything that you want. It is just that if the plane is so far from what you want, why not start with a different plane? :confused:

Kent

I'm glad to see you're enjoying yourself poking fun at people who aren't afraid to try something different. Apparently you would be quite content never changing anything - how is it you're flying a modern 9A instead of an original Cub? Do you think those airframe and powerplant improvements over the years were handed down to Moses on stone tablets?
 
Economy!!!

This is a great forum topic and I am enjoying the debate. I am a long way from making an engine choice since I just started, but I am forming my choice based on this input.

Many of my questions have been answered; however, I would like to pose a previous question on fuel consumption in another way. I may likely be flying from high altitude airports (FTG), but I understand the 9 is good at this altitude with most HP choices. However, the most important factor to me is range. So here is my question.

Assuming fixed prop and mogas, what engine/prop combination would provide the best range? (I will probably add extended range tanks)

As a side question, does the smaller disk of the catto 3-blade reduce economy. I?m thinking the clean air flow beyond the fuselage (edges of the longer prop), is more efficient.

John Edwards
RV-9A ? Slider ? Empennage
N5JE - Reserved
 
Economy with O-320 & Hartzell CS prop from Van's...

I flew into and out of FTG in June 2006 from the Chattanooga, TN area. http://www.n2prise.org/rv9a213.htm#June18

I flew most of the trip at 12,500 or 13,500 MSL and got a fuel burn of 5.5 or 6 gallons per hour. I like the economy of this engine prop combo. The prop hub governor is set to limit RPM at 2,650 for takeoff power for an engine that has a redline of 2,700. I have the ECI equivalent to an O-320-D1A with one mag and a Lightspeed Plasma III with direct crank sensor. That electronic ignition coupled with the C/S prop gives me good fuel economy, even with an airplane that weighs 1,184 pounds empty.

I did all the weight and balance numbers up to and including two 250 pound folks in the seats, full fuel, and 100 pounds of baggage for a max gross weight of 2,000 pounds. There are two sets of V-speeds for the airplane posted on the panel. See the photo at this link: http://www.n2prise.org/rv9a244.htm#June14. I have yet to get an AFT C/G that is out of limits. Taking off at max gross weight is like flying a 172 again, until you get the air speed up to RV speeds, then all is normal. My friend Wendell and I flew to OSH 2006 with the heavy load.

I have the standard 8.5 x 1 pistons for 160 HP with a carburetor, not fuel-injected. The density altitude at FTG was not a problem. I did get the award for the RMRFI longest distance flown to attend. It was a good trip!

Jerry K. Thorne
East Ridge, TN
RV-9A - - N2PZ
Hobbs = 234.7 hours
 
Kent, your concerns are the same as mine- I wanted excess power available for high altitude/summer heat takeoff AND ability to use mogas when desired.

I have no problem with conventional engines other than ridiculous cost, but for me, the best power to weight combo turned out to be the smooth running Mazda rotary (200+hp) and either a lightweight composite Ivo Magnum adjustable prop (not recommended with Lycs' vibration) or 3-blade Catto fp. It certainly takes a bit more work, but I believe the results will be well worth the effort.
 
Hi Greg,

airguy said:
I'm glad to see you're enjoying yourself poking fun at people who aren't afraid to try something different. Apparently you would be quite content never changing anything - how is it you're flying a modern 9A instead of an original Cub? Do you think those airframe and powerplant improvements over the years were handed down to Moses on stone tablets?

I am enjoying myself, and sometimes other respond to a little bit of humor. As I said "I am sorry if it looks like I am picking on anyone, that is not my intention". I am more then interested in anyone having made different selection for engine and props than I have reporting what they have discovered. There have been lots of posting on this thread about combination of engine/prop that are beyond what Vans recommends and I just thought that there was room for another opinion here.

There is nothing wrong with being content never changing anything. And there is nothing wrong with changing everything either. I think that most builders will be delaying getting in the air by trying to make the most modern plane possible. I completely agree that there should be something better the the standard Lyc, but I didn't want to delay flying my plane :( to make sure that I could better the old standard.

RV's and Cubs: I would love to have a Cub to fly. :) My dream would to add a Cub with big tires to my hangar, and I think that I would have room for it when my C712 sales. Two plane with two missions. The only problem is I don't think the wife could be convinced that we need two planes. So I will be sticking with my RV9A for now.

Greg, or anyone else that happens to be up in the Oregon/Washington area and want to have a ride in my flying RV9A, just give me a call/email whatever.

If and when I build my next plane, I will again be evaluating what engines are available for the plane under construction. During building my RV9A I looked at a number of engines as better choices then the Lyc. The ones that I considered during the build were:
1. Mazda Rotary (when to the OSH forum).
2. Small turbine (saw one on a Pacer as Arlington).
3. Eggenfelder (sp?)


All of these choices would have had advantages over the Lyc, but all had their problems also.

When it came down to having to put my money down, I went with a engine from AeroSport. The main reason is it is tried and true and would take very little (relative) effort to put it in. I could get lots of experienced help with this installation. The cost was not much different then most alt engines and a lot less then some.

Happy building to all. I hope to see you join me in the air soon, it's fun to fly RV's.

Kent
 
Yukon said:
Mel,

How does the Catto prop do in rain? Do you fly IFR wth it? Is it as good as an MT in this regard?
I do NOT fly IFR! I've not had a problem with the Catto in the rain, but then again, I've never had problems with wood props in the rain. When I encounter significant rain. I throttle back to below about 2500 rpm and head toward the bright spot. I've been flying wood props in rain (not a lot of hard rain) for 30 some odd years without problems. BTW, I also fly wood props off of short, gravel runways without problems. The secret here is to not go full throttle with the airplane sitting still. YMMV.
 
Why not IFR?

Mel said:
I do NOT fly IFR!

Mel,
This sentence seems to be pretty adamant about not flying IFR. Could you share your reasons/rationale? Many people seem to think these airplanes are quite capable of IFR operations (depending on the panel of course). Your thoughts would be appreciated.
Thank You,
 
Don't misunderstand...

It has nothing to do with RVs. I have quite a few friends who fly RVs IFR. Anyone who gets an instrument rating is much better off for it. I fly strictly VFR. I have looked into getting the rating but could never justify the time or expense for the type flying that I do.
Absolutely nothing against fly RVs IFR.
Now, do I think that the RV is a GOOD instrument platform? Not particularly. Being aerobatic, the RV is not inherently stable. For IFR, if your aircraft is not inherently stable, you do NEED an autopilot.
Just my opinion.
 
Last edited:
flutter

Kentb: Flutter testing is a very very complicated thing. Classic flutter testing is either done with actual flight tests and comparing each flight test with predicted flutter. Predicted flutter is done though very complicated computer analysis with algorithms which compute robust flutter margins based on a computer model of a particular aircraft. Then flight test data is fed bck into the algorithm to predict expanded flutter points and so on until the difference between predicted and actual test resuts is small and a point then is predicted for a flutter to occur. flutter analysis is often tested with a wind tunnel as well. suffice to say that most flutter concerns are at high TAS and generally are more of a concern in transsonic flight. It is inconcievable that Van did any flutter analysis in any depth other then determing dynamic balancing with control surfaces. Certainly no computer programs appear to have been used. After all, Van simply bolted on a Ronz airfoil to an existing airframe and saw how well it performed and started making kits. Hopefully he did some load tests to justify his airspeed limitations, but I am not too sure of that either. As I said, his brother Jerry told a close friend that NO flutter tests of any kind were performed And given the speeds of any of his planes, I would not expect any to have been done. Certainly there have been many incidents where an RV has exceeded the VNE and except for a 6 I know of no structural failure of a wing or control surface and have only heard from a third party that a 4 encountered what was described as an onset of flutter and that was at over 240 kts in a dive. I do not think that there is any 80% rule based on anything any one associated with the company did in the way of tests or computer predictions. I hope that I do not have to eat my words,but I think one will be perfectly safe in treating VNE on the 9 or 9A as an indicated airspeed limitation and not be worried that flutter will occur above 210 MPH TAS should one inadvertently find themselves that fast, which with the normally aspirated engine would take some work to achieve. Just my humble opinion however. I have been wrong on many things, and do not expect anyone to rely on my opinion in this area. But why does VAN not give us more info so as manufacturers we can make informed decisions.
 
Short answer - liability.

As kit builders, we all have to abide by the 51% rule, as enforced by the FAA. As test pilots, we have to abide by the 100% rule, as enforced by the lawyers - meaning that as a test pilot, you are 100% responsible for 100% of the problems you encounter. If he started handed out engineering data, it would be taken as gospel and if even ONE person were to get into a problem as a result of using that data (even superficially) the trial lawyers would all have a field day with Van, and he knows it.

The data may or may not exist - but you can bet your last gallon of 100LL that he will never confirm nor deny it's existence, nor will he ever release it. I wouldn't either, in his seat.
 
lawyers

airguy: i know why van does not release the info and it is for the same reson he argues that 180 hp should never be used on the 9. lawyers! cya is the mfg's mantra in todays society. having said this, however, if there were to be a structural failure leading to deaths, it would be reasonably easy for a lawyer to bring Vans into the case and through discovery get what ever info he has accumulated. after all he has, with or without supporting data, put vne's, and other limitations out there, which we as builders do rely on.
 
And you can bet that his posted limitations have sufficient margin in them to demonstrate that anyone operating at a point that will bend the airplane is operating outside those margins. How big are those margins? Dunno - and he won't say - that's where the whole test pilot thing comes into play. By all means, go explore those margins if you like - but if you break it, you own both pieces.

I feel fairly comfortable exploring the power margins by putting 180hp on a 9A (and effectively making me a test pilot every time I fly it), for the simple reasons that:

1) It's been done competently and safely by several others - if there were dragons in the moat they'd be eating those test pilots;

2) The weight and balance issues are easily solved for the minor changes involved between a 320 and a 360;

and 3) The biggest red flag for the 360 is flutter/Vne - which is entirely pilot competency, not equipment. A stupid pilot can still induce flutter in a 9A powered with a O-290. Keep the speed under control as your instructor taught you to. Unlike the old Cessna I learned to fly in, this airplane really WILL have enough power to bite you if you don't pay attention. Braindead need not apply.
 
Vans, has done wing load testing.

I have seen the pallets of lead shot that they use and even the wings after the test have been done.
I even borrowed some of there bags of lead when I was in phase I testing.
You have to load it to the max when you are doing your testing.

It sure flies better once you get the lead out. :p

Kent
 
load testing

Tthere is no question whether Van's has done load testing. He has. And normally we equate VNE to the max IAS for a particular make and model because of a concern that the aircraft load limits will be exceeded at that speed even in smooth air. I know that design ultimate limits may be higher, but these limits relate to load limitations and in the case of normally aspirated engine aircraft rarely if ever refer to flutter concerns. Flutter testing is very very complicated, expensive and dymamic as opposed to load testing which as was indicated is generally very rudimentary and done with bags of sand or other weights placed strategically about the airframe componets being load tested. Anyone ever heard of an RV encountering flutter, ever? Has anyone ever heard of any other fixed wing, fixed gear normally aspirated engine aircraft having VNE expressed in TAS terms to protect against flutter?
 
Why I Did What I Did

Interesting topic, and a subject that has been number one in my mind ever since I purchased my engine/prop combo for the 9A which I hope to fly by the end of the year.
First, a little pilot background..6000 plus hours, ATP, did 12 Atlantic crossings in my Mooney M20F which I re-designed the instrument panel to carry all modern avionics, and installed all the speed mods that were available. Built and still own a One Design aerobatic aircraft that has a IO-360 180 hp engine and a 3 blade MT prop.
I mention these 2 planes to illustrate that I have some experience with long distance flying, and having flown the One Design 4 times from Mass. to Florida, have experience in engine management with a 180 hp. Lycoming flying cross country.
I believe that choosing an engine/prop combination relies on the missions that you intend to use your aircraft for. For example, if the plane is going to be flown no more than 100 miles per flight, then keep it simple. If it will be used for long cross country flights, then I believe a more sophisticated system might be in order.
After 9/11, there didn't seem to be much fun flying anymore here in the crowded skies of the North East, and that combined with the overzealous airport commission at my airport who considered the tenants as the enemy, prompted me to sell the Mooney which wasn't seeing much use.
Last year, my wife who had done 8 of the 12 Atlantic crossing with me (how lucky can a guy be!!) said to me that since I had sold the Mooney, she had not flown (the One Design is single seat). "Why don't I build us a fast 2 seat plane" I replied, to which she repied "OK"!!!
The 9A was chosen, ordered and was informed by Van's people and forum to not exceed 160hp.
After a month of give and take with engine mods and accessories, it came down to basically the same engine as in the One Design minus the cold air induction and inverted sytem, but with the addition of roller tappets. When I found out I could get a Superior Experimental engine 180hp for the same price as the 160hp, and the weight was just a couple of more pounds (longer cylinders) and it was just one inch wider, it was a no brainer.
After a long discussion with MT about rain and the composite prop, (have only been in rain a few times with the One Design), that was the prop of choice.
On my trips to Florida in the One Design, at 9000' and 21 inches and 2450 rpm, I'm truing out close to 200 mph, and that with the thick aerobatic wing, and fuel burn is about 7.9 gph.
I was concerned about the flutter, and articles written that true airspeed and not indicated airspeed was the guiding factor. Even had a chance to talk with Van about this at Sun and Fun, and was just as confused after the discussions.
What I found with the Mooney was that in a decent, because the plane had gotten so clean with the mods, that the slightest down angle would put the needle to the top of the green. I never flew the plane in the yellow, even in smooth air. I would allow for a decent of 1000 feet per ten miles, and work the throttle and auto pilot decent accordingly. My airport is just about at sea level, so that made it easy when coming home. On my trips I'd fly between 7 and 13,000 feet if winds permitted. This procedure also avoids shock cooling. Just keep pulling the throttle back 1 inch every 10 miles until about 20 miles out then more retard down to pattern speeds.
This is the same way I intend to fly the 9. I intend to use indicated airspeeds to control the throttle, and we do intend to carry oxygen to take advantage of the higher altitudes and speeds possible with the bigger engine. At this time we do not intend to add additional fuel, but what I found in the One Design, with the high climb rate, which the 9 will have, it's no big deal to add a fuel stop. My wife will appreciate that. (On one trip from Gander Newfoundland direct to Shannon Ireland, it took 13.5 hours because of strong cross winds. Not many wives would do that!!)
We're looking forward to many, many cross country trips in the 9A
Didn't mean to ramble on so long...comments welcome!!
Regards
Jack
 
USCANAM said:
Interesting topic, and a subject that has been number one in my mind ever since I purchased my engine/prop combo for the 9A which I hope to fly by the end of the year.

Very interesting. are you using f/p or c/s MT prop? Also carb or F/I? Do you have an opinion on FADEC?
 
Back
Top