V

verrice

Member
Hi there, first post. :)

I've spent awhile looking at kit planes and have concluded that RV is the way to go. Since I intend to regularly fly with 2 or 3 passengers, and want a roomy comfortable plane for XC, the 10 seems a perfect fit.

I've read several of the posts about 210 vs 260hp engines, and a lot of great information is covered. I am, however, still unclear about one aspect. Everyone talks about how the 260hp lycoming can get the same performance as the 210hp by de-rating it and running LOP. Since range is really important to me, I'm very curious about this. I certainly like the idea of having the extra power available, and wouldn't want to be in the 'slowest rv-10' category, but according to the numbers from Van's the 210 has a much better range.

What kind of practical range have you 260 horse folk been getting? Even better would be considering my two longest XC trips would be from North Chicago burbs to Tucson, and to Seattle. The way I figure, even with the listed range of the 210hp, it's still a one stop trip, even if using 55% cruise, though I prefer the 75% cruise timing.

I would go with a constant speed hartzell, blended airfoil (80" if I recall) if going with the 260hp.

Now, being only in the dreaming / planning stages, I have a VERY long way to go, but I'm one to try and come up with as much up front, planning-wise.

It's not the cost difference that I'm thinking about. I want to put in what's right for me, and not skimp. It's all about range and performance, and 10mph more doesn't really get me all that excited. CG safety and all those other issues are a factor, but right now I'm -only- talking about range, and a bit about the time it takes to get there.

Thanks in advance,
Randy
 
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It is all the same.

Hello TIA,

Looking at Vans site/numbers:
260 hp at 55% = 143 hp = 1000 range at 176 mph
210 hp at 75% = 157.5 hp = 951 range at 186 mph

Using math to match them more closely.

210 hp at 68% = 143 hp = about 1000 at about 176 mph.

The about part would be slightly different because of a little heaver engine and a slight different efficiency between the engines. I don't think that either would change thing by more the 1%.

It really comes down to the costs and effort to complete the engine installation. My friend usually flies his RV10 at about 55% power, because he gets there fast enough and it costs less to fly.

Kent
 
verrice said:
Hi there, first post. :)

I've spent awhile looking at kit planes and have concluded that RV is the way to go. Since I intend to regularly fly with 2 or 3 passengers, and want a roomy comfortable plane for XC, the 10 seems a perfect fit.


TIA
Click to expand...

Welcome aboard.

You have come to the right place.
 
kentb said:
Hello TIA,

Looking at Vans site/numbers:
260 hp at 55% = 143 hp = 1000 range at 176 mph
210 hp at 75% = 157.5 hp = 951 range at 186 mph

Using math to match them more closely.

210 hp at 68% = 143 hp = about 1000 at about 176 mph.

The about part would be slightly different because of a little heaver engine and a slight different efficiency between the engines. I don't think that either would change thing by more the 1%.

It really comes down to the costs and effort to complete the engine installation. My friend usually flies his RV10 at about 55% power, because he gets there fast enough and it costs less to fly.

Kent
Click to expand...

Randy actually. ;) TIA = thanks in advance. :)

So really, the range advantage of the 210 is minimal, it sounds, in reality. Right?

I've spent a ton of time looking at peoples build logs, options, specs, etc. The more I do, the more questions I get. :D

Hopefully I can take the plunge soon, but a few financial matters to work out first.
 
Mike S said:
Welcome aboard.

You have come to the right place.
Click to expand...

Thank you. Part of the draw to RV has nothing to do with the planes, but the community around them as well. Though, the planes do have a LOT to do with it. Fast, flexible, easy enough to build, not outrageously expensive (in comparison), and very nice looking. Pretty much a lock for me! ;)
 
Another important point to note is that although 220RV has the TCM 210 HP engine, Van's made the decision to not support that option. There was a survey done of the early builders and very few were interested in that option.

Bob
 
Throw in a high DA day, a flight through the mountains, or you want altitude in your flight plan, and the 260HP looks the best. All the above "erase" horsepower so a few extra ponies to spare make the safety aspect win the debate for me.
 
Ya

When talking to Tom Green after he arrived at a fly in in the RV 10 he said about the smaller motor..."There is no good reason to do it!"

Good enough for me.

Frank
 
What about the XP400/400SRE

I've been lurking around this site for a while and doing some limited research of my own for a few months now. Just six months ago I didn't know people could build their own airplanes. But now I'm extremely interested in building a plane of my own, and the -10 seems to be a good fit.

So here's my question. It seems I read somewhere (and I can't remember where right now) that the -10 has/had some weight and balance issues with the 260hp IO-540 engine--something along the lines of less than desireable landing flare issues--is that right? Well, in the limited research I've done in said last few months, I was wondering what anyone's thoughts were on using the XP400SRE engine instead. It has just a few HP less than the IO-540, but should weigh a lot less. Is this a feasable option?

I also remember hearing different things about the XP400 and 400/SRE, so not sure what everyones' thoughts were. Thanks in advance for the replies.
 
N8Higgies said:
I've been lurking around this site for a while
Click to expand...

And now you have come out of the shadows-----------

Welcome aboard.

Wise decision.

As to the XP400, a few problems off the top of my head. Too light, too short, both of which a new longer mount will help, battery will have to be fromt mounted more than likely, which wont be much of a problem, but the biggie I see is---IIRC this is an engine targeted for the racing crowd, and not really suited to sport/pleasure flying.

The 10 can be a bit nose heavy with two big guys in front, and nothing in the rear seats, or baggage compt. But that is part of the design, otherwise you would be pretty limited in back seat and baggage capacity. It is just a function of the CG location/range.

As in most things aviation wise, this is a trade off.
 
I've read the same about the 10 with the 540 being a little nose heavy. I've never seen anyone say really nose heavy, dangerous, or unable to flare. Seems to be more of just enough that you should be aware of it.

I would certainly take a little nose heavy when solo or two up over being tail-heavy when four up with baggage. JMO
 
Just a bit of clarification, when I refer to nose heavy, I mean stick forces.

Not an out of CG problem. You just feel it in the stick.

Both the front seats, and the fuel tanks are quite close to the front end of the CG range, when you start putting people and baggage in, there is still a comfortable amount of range for the CG to move aft.

The addition of 25 or so pounds in the baggage comp makes a nice difference, when flying solo, or front seats only.

Another quirk of the 10 is full flaps with a forward CG----gets a bit "goosie", but raise the flaps just a small amount, and it goes away.
 
TIA,

I will place a shameless plug for my engine builders and friends at Barrett Precision. I have their stock IO-540 with standard induction. Make a phone call to Rhonda and she will answer all your questions or get Allen or Monty to do it. Don't waste your time on the Continental that Van's has on N220RV, I don't think they plan or may not even now be supporting it. After you shove the throttle in on a 540 powered model,:p you'll know why you went with the 540.
 
Mike,

When it comes to aviation, you can NEVER be too light or in the context of an accessory, too small. You are after all defying gravity. If someone came out with a 250 hp engine the size of a shoe box weighing 100 pounds, that and a couple of batteries up front would make a really fine RV-10 power plant:)

Knowing then that I already have in my possession a new IO-540, I actually think an XP-400 or even an IO-390 would be a fine power-plant for the RV-10 in these days of $5 avgas. I say this only because I currently fly behind a 1800 pound empty, 2800 pound gross, 200 HP C177RG which is a super efficient cross country machine that will true at 148 kts. With an IO-540 I could probably get another 20kts burning an additional 4 gallons per hour, but with avgas at $5, that ain't hay. Granted I'm in the northeast with not a lot of mountains to clim over, but in this environment, it climbs well, goes far and dosen't cost a lot to feed. And no, you could never be as efficient throttling back a big engine to the levels of a smaller engine. You still have the extra weight of the big engine to carry around.
 
William, while I agree with you totally about weight in an aircraft, I think you took my comment a bit out of context.

The guy I was replying to didnt even know about home built aircraft 6 mo ago, by his own statement. I was trying to point out the problems with trying to substitute a lighter engine---and shorter--- in the same airframe, unless there is a new mount pushing the engine way forward, probably beyond what the existing cowl will accommodate, the CG probably wont fall where the design point is. It will probably be in range, but then the side effect will be to limit rear seat and baggage load.

Your 250hp, 100lb, shoebox would require a 10 or 12 foot long mount to get the necessary moment, otherwise, if such a thing existed, (some derivative of a turbo Wankle??) it would work just fine. Could even use a pretty streamlined cowl..............

Anyway, mental gymnastics aside, the whole thing is doable, will take work, and design modifications. It just has consequences that I was trying to point out.

TANSTAAFL.
 
w1curtis said:
Mike,

When it comes to aviation, you can NEVER be too light or in the context of an accessory, too small. You are after all defying gravity. If someone came out with a 250 hp engine the size of a shoe box weighing 100 pounds, that and a couple of batteries up front would make a really fine RV-10 power plant:)

Knowing then that I already have in my possession a new IO-540, I actually think an XP-400 or even an IO-390 would be a fine power-plant for the RV-10 in these days of $5 avgas. I say this only because I currently fly behind a 1800 pound empty, 2800 pound gross, 200 HP C177RG which is a super efficient cross country machine that will true at 148 kts. With an IO-540 I could probably get another 20kts burning an additional 4 gallons per hour, but with avgas at $5, that ain't hay. Granted I'm in the northeast with not a lot of mountains to clim over, but in this environment, it climbs well, goes far and dosen't cost a lot to feed. And no, you could never be as efficient throttling back a big engine to the levels of a smaller engine. You still have the extra weight of the big engine to carry around.
Click to expand...

William,
The thing about the use of a 390 4 cylinder is you will need to feed it just as much fuel to go the same speeds. A bit less for climb, but there is no real dramatic advantage there. Since you would have to manufacture a bunch of new things yourself, you have to ask is it worth it? It takes a certain amount of power to push the plane at 200 mph. The 390 would use similar amounts of fuel to go fast. The only thing a smaller engine would do better is fly a slow as possible with a small throttle opening. You would then have lower fuel flows. Since most of us don't tune for that range I'd suggest staying with the 6 cyl. It should be smoother as well. If you like slow cruise flight a smaller engine might be the way to go. FWIW
Bill
 
Rotary10-RV said:
William,
The thing about the use of a 390 4 cylinder is you will need to feed it just as much fuel to go the same speeds. A bit less for climb, but there is no real dramatic advantage there. Since you would have to manufacture a bunch of new things yourself, you have to ask is it worth it? It takes a certain amount of power to push the plane at 200 mph. The 390 would use similar amounts of fuel to go fast. The only thing a smaller engine would do better is fly a slow as possible with a small throttle opening. You would then have lower fuel flows. Since most of us don't tune for that range I'd suggest staying with the 6 cyl. It should be smoother as well. If you like slow cruise flight a smaller engine might be the way to go. FWIW
Bill
Click to expand...

Being that my goal is to get as far as I can, as fast as I can (not as slow), I think I'm sold that the bigger engine is the way to go. In graphing the ranges, based on information from Vans, the 260hp engine, at 55% power, will get you almost the same distance as the 210hp gets in at 75% power, in the same amount of time.

210hp @ 55%: 1020sm in 6 hours
210hp @ 75%: 950sm in 5 hours
260hp @ 55%: 900sm in 5 hours
260hp @ 75%: 800+sm in 4 hours

Add to that my intention to traverse mountains, and likely deal with high DA, I'm thinking the 260 (IO-540) makes sense. At 75% the 260 can make it nearly 1000sm in 4 hours... that's more than half my most common expected XC route (to Tucson). I am interested to know what the real world GPH ratings are like that but in sticking with the numbers from Van's, I'd have to assume that:

Bear with me, I'm partly working this out for myself, but please, if someone sees something inaccurate, please let me know. Also remember I'm dealing with 'ideals', no wind, standard pressure, etc. to get a comparison.

260hp @ 75%:
Range being 825sm, and speed being 201mph:
825sm / 201mph = 4.1 hours

Add assumed safety margin of 45 minutes:
4.1hrs + 0.75hrs = 4.85 hours

Fuel being full with 60 gallons and consuming all fuel in the above time
60g / 4.85hrs = 12.37gph

260 @ 55%:
Range being 1000sm, and speed being 180mph:
1000sm / 180mph = 5.5 hours

Add safety margin of 45 minutes:
5.5hrs + 0.75hrs = 6.25 hours

Fuel full at 60 gallons and using all in the tanks:
60g / 6.25hrs = 9.6gph

210 @ 75%:
Range being 951sm, and speed being 190mph:
951sm / 190mph = 5 hours

Add the 45 minutes:
5hrs + 0.75hrs = 5.75 hours

60g / 5.75hrs = 10.43gph

210 @ 55%:
Range being 1,153sm and speed being 170mph:
1,153sm / 170mph = 6.78 hours

6.78hrs + 0.75hrs = 7.53 hours

60g / 7.53hrs = 7.97gph

Does that all look correct? Do you see similar GPH performance in your IO-540s?

This of course isn't taking in account LOP or any other such business. Like I said, I can only go by what's available on Van's site.

So for a comparison... if you fly for 4 hours at 55% power with the 260hp, versus flying 4 hours at 75% power with the 210hp:

Engine / Range / Fuel Used
260 / 720 sm / 38.4g
210 / 760 sm / 41.7g

For 40 extra miles you burn 3.3 more gallons of gas in the lower hp engine, or $16.50. To make up the distance in the 260hp you would have to fly an additional 13 minutes, or 2g, or $10 of fuel...

I sure hope that makes sense to someone other than just me! :D

Reminder, these are based of Van's numbers found at: http://www.vansaircraft.com/public/rv-10per.htm

Thoughts? :)
 
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Okay, for fun... the 210hp @ 55% for 4 hours, vs the 260hp @ 75% for 4 hours:

Engine / Range / Fuel Used
260 / 804sm / 49.48g
210 / 680sm / 31.88g

For the 210 to achive the 720sm that the 260 got at 55% power, it must fly for an additional 15 minutes or nearly 2 more gallons of gas. To reach the 760sm that's 30 minutes and 4 gallons of gas... so $20 dollars in fuel (going with $5/g for ease).

So summary:
Engine / % cruise / Distance / Time / Fuel Cost @ $5/g
260 / 55% / 760sm / ~4.25hrs / $202.00
260 / 75% / 760sm / ~3.75hrs / $233.80
210 / 55% / 760sm / ~4.50hrs / $169.40
210 / 75% / 760sm / ~4.00hrs / $208.50

Wow... that was a lotta cipherin'! ;)

Looks pretty close... now that I see it like that. Close enough that the bigger engine, I think, has the better flexibility for range * time * cost...

Okay, now I'm done... hehe
 
Rotary10-RV said:
William,
The thing about the use of a 390 4 cylinder is you will need to feed it just as much fuel to go the same speeds. A bit less for climb, but there is no real dramatic advantage there. Since you would have to manufacture a bunch of new things yourself, you have to ask is it worth it? It takes a certain amount of power to push the plane at 200 mph. The 390 would use similar amounts of fuel to go fast. The only thing a smaller engine would do better is fly a slow as possible with a small throttle opening. You would then have lower fuel flows. Since most of us don't tune for that range I'd suggest staying with the 6 cyl. It should be smoother as well. If you like slow cruise flight a smaller engine might be the way to go. FWIW
Bill
Click to expand...
Bill,

My statement were all hypothetical since there is no IO-390 firewall forward package available. But if one was available, all I'm saying is that it would still be a fine flying aircraft and be a LOT more efficient than an IO-540 equipped aircraft up to a certain airspeed. I did not nor would anyone think that an IO-390/XP-400 engine would fly at the same speed as an IO-540 RV-10. That is why I gave the example of my Cardinal with it's 200 HP IO-360 engine.
 
What I think some of you are trying to say is that the fuel burn of a IO540 and a four cylinder, going the same speed is the same. To knit-pick, the weight and cylinder drag on the IO540 would be slightly higher, but really probably insignificant. The 6 cylinder could just go faster and climb quicker which would burn more fuel. If you wanted to go, for example, 150 kts, the fuel burn of the two RV-10s would be very similiar in cruise. You might see a less than half gallon an hour difference in cruise due to the above mentioned factors. Factor that over a 2000 hr TBO and add in the increased fuel flow during climb of the IO540 (yes you would use full power to climb) and you might be looking at 2000 extra gallons, at least, over the life of the engine, more if you went faster than 150kts. That's at least $10K. If you chose a 200hp you wouldn't need the high performance addition on your insurance and at overhaul the four cylinder would sting slightly less too.

That being said, I am still going to be putting an IO540 in.:D
 
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