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RV-12 in the mountains

rockwoodrv9

rockwoodrv9

Well Known Member
Patron
I live in Colorado. The closest airport is Aspen at 7820' and Glenwood Springs at about 6100'. My plans have been to build a RV 9 to use mostly for travel up to 500 miles, with most trips between 100 to 250.

I just read the article in Kitplanes about traveling in a RV 12 and did the financial math comparing the two airplanes. For a 200 mile trip, the 12 at 120 mph and the 9 at 170mph, there is a difference of 30min. On 500 miles, it is 1:20. The fuel for the 200 mile trip cost $40 more. That isn't huge, but does add up. The biggest cost savings is in tie down if I was willing to trailer the 12 to my ranch. that would easily save $2400 year.

None of this means anything if the 12 does not have the power to overcome altitude and density flying in the Rocky Mountains. Just a hop over to Denver would put me at the ceiling limits of the 12.

I know there are 12's in Colorado, I have been reading this thread and read about many of your projects and airplanes. What are your experiences with the air density in the summer flying into the higher elevation airports and over the mountains? I know Vans specss the Rotax for the 12 - maybe there is a different engine that would increase the ceiling and climb to make it a better mountain plane but still takes autogas. I would sure be interested in your thoughts. I think both of the planes are extremely well designed for their purpose and I would love to build and fly either of them. After reading the article in Kitplanes, it opened the 12 to consideration by me.

Below is a chart of costs differences. I have no idea on how it will format in this post, but hopefully you can look at it and see if I assumed correct numbers. On that note, I just saw that 100ll is $7.79 at the Aspen airport. Holy ****! Thanks for the info.

RV 12 RV 9
Kit Cost $65,000.00 $65,000.00
Gallon/hr 4.5 8.5
Fuel Cost $3.75 $6.79
$16.88 $57.72
RV 9 fuel over cost p/h $40.84

200m/120mph/170mph 1.7 1.2 0:30
500m/120mph/170mph 4.2 2.9 1:20

Hangar Rental / Year $0.00 $2,400.00
 
Remember.....

You don't have to cruise the RV-9 at 170 mph. If you throttle back to around 50% power your fuel flow will not be that much greater than the -12 and the speed will still be noticeably higher.
I think you will find the -9 to be much more versatile than the -12.
And on the practice of removing the wings to save tie-down, think about it long and hard. If is possible but most people will find it not very practical.
 
You can also burn mogas in the RV-9, so that would affect your numbers. If higher, faster, and farther is what is important to you, go with the 9. Another big consideration is the ease, time required, and difficulty of the build. I don't have numbers to back it up, but I'm guessing to fall-out rate for first time builders is significantly higher for the 9 as compared to the 12.
 
If you have and can continue to get a medical, I'd go with the -9 in the mountains, if only for the better hot/high performance and higher usable cruise altitudes, particularly if you go with the CS prop on the -9. This would be different if you could use a CS/in-flight variable-pitch prop on the -12, but this wouldn't qualify it as LSA anymore.

If you have any concerns about your medical, the -12 is the way to go.

As others have said, you can burn mogas in a -9 with the proper compression ratios.

TODR
 
I am building a -12 out at Meadow Lake in Colorado Springs.. Happy to show you what the build looks like if you lean that way. I also own a Gobosh 700 with the same 100 HP Rotax 912. I, along with about 6 other Rotax 912 powered planes flew into Buena Vista a couple months ago with no trouble at all. I also have flown a 912 powered Gobosh into Leadville. So long as you follow mountain safety rules, mind the winds aloft very closely as the LSA's are . Well light, it is doable.

As a sport pilot the -9 isn't an option for me.

Carl
 
medical is an issue

The medical is an issue. I will have to "play the game" and go off a prescription for the time necessary to qualify and receive a medical. Then I will not renew it. It is my hope that the rule changes proposed by EAA and AOPA will pass and the 9 will be one of the planes allowed.

I didn't consider throttling back to save on fuel in the figures just to make them even. I wanted to do the estimate using optimal use of the planes design capabilities. In real life, you know the numbers better than I and cutting back on speed in the 9 is a real option to take advantage of when desired.

I haven't talked to any 9 pilots who use autofuel in their planes. I know it is allowed, just haven't looked into it enough. If it works well and doesn't cause engine problems, that would be the ticket. What about auto fuel for most of the mixture and maybe throw a few gallons of 100ll into the tank for a little octane boost?

i will research the autofuel in a 320 and see what peoples experiences are. I think both the 9 and the 12 are great planes.As mentioned, probably most people will not remove the wings after each flight, but maybe if a snowstorm is coming up, put it in the trailer and use an outside tie down the rest of the time? Both have their advantages - difficult decision. The over-ridding factor may be the increased climb and ceiling with the 9. Thanks for the info.
rockwood
 
12 in the mountains

I have flown a 12 through the mountains without any troubles. Made the trip out to Van's twice from Arkansas. The route was KLAR - KRKS - KMAN - KGCD...Several times I was up to 11.5 with no trouble. It does take it a while to get there and you certainly will have to make sure you go around rather than over, but the little 12 is certainly capable.

One note is that this was not done at gross weight, but I did have 75lb of stuff, full fuel, and my 170lb.

If I weren't planning long distances, I would prop it for climb and not give it another thought.
 
12ing in the mountains

With lots of PIC time in the books flying an RV7, RV10 and now an RV12 out west in the mountains, I woud endorse all of the positive notes posted so far. The 12 easily makes it up to its 14k service ceiling when at mid range weights, and unlike many spamcans flies solidly rather than nibbling the edge of a stall up there. It is really quite a remarkably capable cross country machine on good weather days with less than 30kts of wind at the ridges, and no risk of icing. Toss in any concern about topping the clouds or stiff headwinds and I'll take a 170kt RV10 with a 22k service ceiling, thanks! The RV7 was not quite as comfortable a high flier as the -10 in the sense that it would start feeling a little mushy on the controls starting at about 16k, but had lots of power (it was the 200hp version) even in the mid- teens.

The RV9 build (essentially an RV7 with a similar wing to the 10 in smaller scale) will be *way* more hours and difficulty than the 12. Took 2000 hrs to get the 7 flying and only 550 for the 12. And the number of hours requiring two people driving and bucking flush rivets is very substantial, meaning you can't go out and just work by yourself in the shop for those phases of the build for any of the flush rivet RVs.

Either way, 12 or 9, you'll love the end product.

-Dan Masys
 
Rotax 914?

The South African guys who flew around the world in their 4-seat Sling recently used a Rotax 914, specifically to improve high altitude performance. I don't know what it would take to put a 914 in an RV-12, and it would obviously mean building EAB, but maybe worth a look? There has been discussion on the forum about several alternative engines for the -12, but I can't recall seeing anything much about the 914 as an option for mountain flying.
 
An aircraft with a 13,800' service ceiling would not be my choice to fly in and out of Glenwood Springs. The fuel economy issue is over hyped and far less important than climb capability. Just my opinion.
 
Ron - the 9 has been my dream plane all along. If there was an engine that would get the 12 up to about 15k ceiling, it would be an easier choice. The idea of the 914 is interesting. The thought of 500-600 hours over 2000+ hours to build is another big consideration. In the end, I will probably go with the 9, but not until I weigh all the options. As a stock 12, I agree, the elevation of the mountains and the ceiling on the 12 are just too close.

thanks.
 
Personally, I'd be surprised if more than one or two people regularly trailered their plane to or from the airport. If you had a hangar, then it might be practical, with the proper cart and other tooling for the wing, but not otherwise.

I'd be equally surprised if more than a handful of people regularly kept their plane tied down outside. After putting that time building it and selecting your favorite paint scheme, it's just not going to happen.

Also, the difference between an airplane that's not performance limited in the mountains and one that is, is tremendous. One thing worth considering is the time difference between flying the -12 at a speed close to best rate of climb, and a -9 at a speed closer to cruise.

Finally, the difference between having a plane that can go up to whatever altitude you wish to fly it at, or having one that's limited to 2,000 AGL or 10k' MSL, or limited by performance, can't be ignored.

On the other hand, if you need an LSA, then the -12 is perhaps the best all around one available. The Carbon Cub LSA (and even E-LSA), though, offers some strengths in a different section of the envelope than the -12 does, and might be worth considering.

Dave
 
Vlad said:
Rockwood when you start flying you go broke with either one :D
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Ain't that the truth!

The cost to operate/feed a RV-12 and a RV-9A are going to be quite similar. Insurance will cost nearly the same, hangar fees will be the same (you won't be trailering your -12 regardless of what you are thinking now...) and fuel cost/gal will be similar because you will seldom be able to buy autogas when you are away from your home airport.

So the decision is based on mission profile, not cost. Go with the plane that best matches your intended use of the plane, knowing you will have a capable and enjoyable aircraft in either case to fly on your way to financial ruin. ;)

If the medical is a deal breaker, wait to see what becomes of the EAA/AOPA petition. If it flops then the -12 is your plane.
 
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rockwoodrv9 said:
The thought of 500-600 hours over 2000+ hours to build is another big consideration.
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I can't imagine the -9 taking 2000 hrs unless you really stretch it out. I built my -6 in about 1700 hrs and it had absolutely NO HOLES in the kit. We even had to cut out the lightening holes. The -9 should take no more than 1400 hrs. Even less with a quick build kit.
 
I guess I was dreaming about putting the -12 on a trailer. It looks so easy in the video! The more I try to second guess myself and justify not doing the -9, the more I convince myself the -9 is the right plane. It is the plane I have been dreaming of for several years - you gota build your dreams.

The medical is an issue and the way the EAA and AOPA have written the proposed changes, it doesn't really help most pilots who want to move from LSA to private. The rules say to use your DL for the medical to use the new planes, you have to have private pilot license first. They are not simply adding planes to the LSA category. They say this is the best they can do and still get it approved. I personally think they are wrong and should fight for a DL medical for all light single engine under 200hp. I am going to have to play their little game to get a medical, finish my private license, then let the medical expire. It is a joke, but there isn't much choice since EAA and AOPA came up with the proposed rules. I haven't seen LSA pilots falling out of the air because of medical issues - I don't believe we will see private pilot licensed pilots falling out of the sky if the class 3 is eliminated. BUT - that is another thread!
 
Mel said:
I can't imagine the -9 taking 2000 hrs unless you really stretch it out. I built my -6 in about 1700 hrs and it had absolutely NO HOLES in the kit. We even had to cut out the lightening holes. The -9 should take no more than 1400 hrs. Even less with a quick build kit.
Click to expand...
Oops. I've taken 2400 hours to build my slow build, not including all the thinking, researching, and headscratching time. I know others could do it faster, and I could too my second time around, but I would caution against assuming most will be able to do it in less than 1500-2000 actual build hours. Airframe in 1000-1400 hours. Sure, no problem. A lot of it really depends on how much one knows about electricity and FWF. Just another data point.
 
Everyone has made excellent points. You have obviously done much research.

I will add two issues to the RV12 VS RV9:

They are each great planes meeting different missions.

1) RV12 WING REMOVAL:
Realistically, removing wings is easy if you have TWO people. Will you have two people when you want to remove the wings? I live near Van's and see what they do to load the plane and wings to a trailer. Not likely you will ever do it alone.

2) MISSION:
Picking the plane spec ed your mission is a Safety Priority above all else. I Don't know all your mission needs, but the portion you described leans heavily on the RV9 to meet safety issues. Safety should be taken seriously in aviation of course. As you know already. (Many others learn from these posts)

Finishing the Private Pilot exam, check ride and dealing with the medical exam, (one time,) is an agreed hassle. Although, when options are weighed, it still seems that having the extra power for takeoff at higher altitude, extra wing for climb at higher altitude and extra available ceiling makes the RV9 a real winner for your mission needs for Safety. Note: Van's employees prefer flying the RV9 for trips.
Keep us posted on your decision and progress. Good Luck.
 
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Autofuel

In the Lycoming up to 8.5:1 CR works just fine. The engine doesn't care and you won't foul the plugs with lead.

I run almost exclusively prmium mogas with 10% ethanol unless I have no choice.

I do have an electric only fuel pump system in the wing roots but others with the standard system seem to do OK. I honestly don't know how the standard mechanical fuel pumps withstands ethanol.

I use P mags with a mac of 38 deg advance and run lean of peak all the time in cruise.

If I had a 9 I'd probably drop an IO360 in it with a FP prop..You'll only get about 160HP anyway with a cruise prop. Others have put 360's with CS props..I don't know if I would go that far.

In my expeience, airplanes that you plan to fly near their limits have little margin..I.e if you need ti get 14k, then have an airplane that will get to 18k in perfect conditions..not 14... But thats just my preference.


Frank
7a IO360
 
I have done it by myself, one person attach and removal is no big deal really with the right additions. Not so sure about putting them in a trailer by myself.
NickAir said:
1) RV12 WING REMOVAL:
Realistically, removing wings is easy if you have TWO people. Will you have two people when you want to remove the wings? I live near Van's and see what they do to load the plane and wings to a trailer. Not likely you will ever do it alone.

.
Click to expand...
 
Given the medical issues, I suggest putting off the decision (if you can stand it that long!) until the AOPA/EAA petition either is approved or not. If not, then the choice is obvious.

greg
 
hufise said:
In a 80 hp rotax zenair over 7000 ft in switzerland
http://www.youtube.com/watch?v=pv3lZzfiEec

Rv project on hold
Daniel Schmid # 12383
Click to expand...

Nice one Daniel.

I must get on the waiting list for a hangar at Speck, where you landed in the video clip, as that is my nearest field. You only live about 20 minutes away from me. It would be great if you want to come and pay a visit to my house and workshop in Gibswil near Wald.

Take care over those mountains.

Tony
 
Greg Arehart said:
Given the medical issues, I suggest putting off the decision (if you can stand it that long!) until the AOPA/EAA petition either is approved or not. If not, then the choice is obvious.

greg
Click to expand...

Above is the best answer from Greg. Wait to decide until the above is complete. Hopefully it will be to your advantage.
 
Don't hold your breath on the EAA/AOPA initiative...it is simply a GAMA move to sell more certified airplanes. It has been shot down before. You have to remember that the Sport Pilot/LSA rules were initiated by faster and more capable ultralights...and how to grab control of these "no certificate necessary" rocket ships. It was not initiated by EAA or AOPA. In fact, AOPA opposed it. Now that the $250,000 C-172 is choking, as is Piper...allowing 180hp driven aircraft would at least put them back in the training business...maybe. Lycoming/Continental STC's do not allow ethanol. All fuel prices continue to rise but mogas will always be cheaper.

It is all about your mission as many have said. I could be wrong of course, but I am thinking this latest initiative will die as well. Good luck.
 
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914 engine in the RV 12

I don't know enough about the RV 12 to know if a Rotex 914 turbo could be a choice for high altitude flying. I was looking at the Rotex site http://www.rotec.com/ and they have the 914, 0-time, turbo for under $30k. I imagine about any engine could be mounted to any plane, but wondering if it had been done before. It could make a difference in the mountains of Colorado giving better performance adding to the safety margin.

A couple questions come to mind - would the 914 be to much engine to qualify for LSA? Maybe a climb prop would limit the speed enough. The other question is how much additional maintenance the turbo would add. Im not even sure if a turbo is allowed in LSA? I will have to look that up.

I am going to do a search to see what I can find about the 914 and the RV 12.
 
Rotax 914

rockwoodrv9 said:
I don't know enough about the RV 12 to know if a Rotex 914 turbo could be a choice for high altitude flying.
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These comments from the guys who flew the Sling 4 around the world recently may be of interest:

Where the standard Sling customarily uses a 100hp Rotax 912 ULS engine, the Sling 4 will be fitted with the 115hp turbocharged Rotax 914 UL engine. Although a 15hp difference doesn't sound like the world, the turbocharged engine gives full power at up to 15 000 feet, at which altitude the 100hp would only be delivering approximately 55hp. So on a hot day in Johannesburg the swing in power between the 912 ULS and 914 UL engine is in the vicinity of 36%, not just 15%.

Secondly, the Sling 4 is fitted with the extremely robust and high quality Warp Drive constant speed propeller system. The main consequence of this is that right from the beginning of the take-off roll the engine can be set to rev at a level that provides optimum power. In addition the aircraft can be set to cruise efficiently with minimum fuel burn.

Keep in mind of course, that Vans designed the RV-12 engine mounts and airframe to handle 100hp, not 115hp.
 
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Predator and the 914

I never realized it before just recently but the AF Predator unmanned aerial system uses the 914. Here is some info on it.. note it can cruise at 25K feet.

The production version of the Predator aircraft is equipped with a turbo-charged Rotax 914 engine producing 105 horsepower. The aircraft measures 27 feet (8 m') long, 6.9 feet high. The Predator weighs 1,130 pounds (512 kg) empty, and 2,300 (1,043 kg) pounds Maximum Take Off Weight (MTOW). On a typical mission the Predator cruises at an altitude of up to 25,000 feet and 70 ? 84 mph, with maximum speed of 135 mph.
 
newamiga said:
I never realized it before just recently but the AF Predator unmanned aerial system uses the 914. Here is some info on it.. note it can cruise at 25K feet.

The production version of the Predator aircraft is equipped with a turbo-charged Rotax 914 engine producing 105 horsepower. The aircraft measures 27 feet (8 m') long, 6.9 feet high. The Predator weighs 1,130 pounds (512 kg) empty, and 2,300 (1,043 kg) pounds Maximum Take Off Weight (MTOW). On a typical mission the Predator cruises at an altitude of up to 25,000 feet and 70 ? 84 mph, with maximum speed of 135 mph.
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My understanding is the turbo on the drone is on the other side of the engine. They have the turbo existing removed and a different one installed on the other side. the company in Canada doing the change has the turbos that were removed and takes a run out engine, overhauls it to 0-time, installs the turbo and sells them for about $10k less than new. it puts it at a pretty good price.

It is about 25 pounds heavier than the 912uls and that could make a difference in structure. I am not by any stretch enough of an engineer to determine if that could be overcome. In my mind, just making a mount that fits would probably not be enough. I have less worry about additional speed because that is controllable by the pilot - as long as they had the discipline to throttle back.

It is an interesting thought to put the 914 on the -12. Maybe that is all it is. From several comments and PM's I have received, it looks like the 912uls does a pretty good job in the hills. Thanks for the info everyone. I plan to keep looking into it as I decide between the -9 or the -12.

Thanks, Rockwood
 
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