I want to build an RV, but I want an RV with two aircraft engines and centerline thrust. Has anyone modified their RV to allow for a second engine? I would like to make it an aircraft that I would feel comfortable flying real IFR at night in since losing an engine would be a non event. A centerline thrust RV should with either one of the second engines be capable of continuing to the nearest airport and if necessary climbing 1000 fpm. I was thinking of modifying an RV-10 with a Cessna 337 type tail or doing the same to a RV-7A or RV-8A. I hate to reinvent the wheel and hope someone else might have done something like this to his RV.
Van's Air Force
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RV with two engines and centerline thrust
- Thread starter RV337
- Start date
To get a 1000 fpm climb on one engine with the other shutdown is going to take a lot of power. Its possible but your going to have a aircraft that burns a lot of fuel. If you want to improve reliability I would look in the direction of a small turbo prop. How much fun would a Rocket be with a lightweight 300 HP turbine in the front?
George
George
Toobuilder
Well Known Member
As stated above, what you suggest is not a modification, but an entirely new airplane.
However, if you are interested in design I would suggest visiting here. It is exactly for the design exercise you are interested in. VAF is a site that supports the assembly of pre manufactured aircraft kits, not design engineering or fabrication.
If you really want a C/L thrust home built twin, you would be better off building one of these: http://www.337skymaster.com/defiant.htm . Designed by Burt Rutan, there are a few out there flying. Plans are no longer available from Rutan Aircraft, however every so often a set of plans or partially completed project hits the market.
N395V
Well Known Member
Every now and then a partially complete Rutan Defiant kit comes up on Barnstormers. Engineering has already been done.
http://www.google.com/search?q=rutan+defiant+photos&hl=en&rls=com.microsoft:en-us:IE-SearchBox&prmd=imvns&tbm=isch&tbo=u&source=univ&sa=X&ei=IOazTpfnFdKgtgeCz4TOAw&ved=0CB4QsAQ&biw=1280&bih=613&sei= IuazTuHDMMK1tweG9Yn6Aw
Just do not kid yourself though, losing and engine in a twin, centerline thrust or not, while IFR is not a "non event".
http://www.google.com/search?q=rutan+defiant+photos&hl=en&rls=com.microsoft:en-us:IE-SearchBox&prmd=imvns&tbm=isch&tbo=u&source=univ&sa=X&ei=IOazTpfnFdKgtgeCz4TOAw&ved=0CB4QsAQ&biw=1280&bih=613&sei= IuazTuHDMMK1tweG9Yn6Aw
Just do not kid yourself though, losing and engine in a twin, centerline thrust or not, while IFR is not a "non event".
flyboy1963
Well Known Member
other options?
do a search for a couple of very smart guys from South America? they built a velocity type ship, with 2 auto engines, driving a single prop.
that's about as close to your requirements as you can get!
http://www.infortel.com/cozy/
oh, I see Velocity is also in engineering phase on a true twin pusher.
do a search for a couple of very smart guys from South America? they built a velocity type ship, with 2 auto engines, driving a single prop.
that's about as close to your requirements as you can get!
http://www.infortel.com/cozy/
oh, I see Velocity is also in engineering phase on a true twin pusher.
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DanBaier
Well Known Member
An old adage is
...that all the second engine does is take you to the scene of the accident.
Putting that aside, from a dollars and cents point of view, you'd be much better off looking for a decent Beech Travelaire (BE-95) or a Twin Comanche (PA-34 or PA-39). Both have Lycoming engines - the Travelaire with O-360s and the Comanche with IO-320s. I think the Travelaire is a little easier to land and perhaps a little faster, but the Comanche is pretty economical on fuel and with add on tip tanks and add on nacelle tanks, you can put on 150 gallons and fly about 8 hours with reserve at 160+ knots.
This all assumes that you don't have to deal with icing conditions - the answers change if you do. Just another point of view -
Dan
...that all the second engine does is take you to the scene of the accident.
Putting that aside, from a dollars and cents point of view, you'd be much better off looking for a decent Beech Travelaire (BE-95) or a Twin Comanche (PA-34 or PA-39). Both have Lycoming engines - the Travelaire with O-360s and the Comanche with IO-320s. I think the Travelaire is a little easier to land and perhaps a little faster, but the Comanche is pretty economical on fuel and with add on tip tanks and add on nacelle tanks, you can put on 150 gallons and fly about 8 hours with reserve at 160+ knots.
This all assumes that you don't have to deal with icing conditions - the answers change if you do. Just another point of view -
Dan
twsurveyor
Well Known Member
Amazing how many people come up with ideas for a "Better Mouse Trap"!
One time I had a guy call me to come over to his house and look at his "mouse trap". He had a 14' jon boat with a big squirrel cage fan mounted to the transom. It was powered (via a fan belt) by a 10hp Briggs & Stratton lawn mower engine mounted atop the rear seat (his grass hadn't been cut in weeks). He was really proud of this thing but the real reason for having me over was, he wanted a copy of my RV-6 wing drawings so he could build a set of wings and make this thing a "flying boat"! I promise you folks, you can't make these things up!!!
Makes you wonder why Van don't think of things like this.
NOT
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Michael White
Well Known Member
Is that a rhetorical question?
"The most fun you can have with your clothes on" comes to mind...
Mike S
Senior Curmudgeon
Welcome to VAF!!!!
John, welcome to VAF.
As to your question, here are a few things to consider.
I would think a 7 would be a better start than an 8, due to fuse length.
A rear engine is going to raise havoc with the C/G, and the shorter fuse of a SBS will mitigate some of that. You will still need to extend the front engine mount, I would imagine.
The wing structure will have to be re-engineered to carry the additional weight, the additional load of the tail boom attachment, the additional fuel capacity ETC.
The fuse will need to be re-engineered to carry the additional weight, the additional vibration issues will have to be analyzed and dealt with, and of course the landing gear will need a total re-design.
The tail volume will most likely not work with the reworked balance of the aircraft, and will need to be re-engineered also.
Not much RV left by the time you get done, is there?
Anyway, I am not an engineer, so my thoughts are only a SWAG, but you get the idea. Pretty sure I have missed a few things.
Thanks for the chance to do a bit of mental exercise
As I said before, welcome aboard.
John, welcome to VAF.
As to your question, here are a few things to consider.
I would think a 7 would be a better start than an 8, due to fuse length.
A rear engine is going to raise havoc with the C/G, and the shorter fuse of a SBS will mitigate some of that. You will still need to extend the front engine mount, I would imagine.
The wing structure will have to be re-engineered to carry the additional weight, the additional load of the tail boom attachment, the additional fuel capacity ETC.
The fuse will need to be re-engineered to carry the additional weight, the additional vibration issues will have to be analyzed and dealt with, and of course the landing gear will need a total re-design.
The tail volume will most likely not work with the reworked balance of the aircraft, and will need to be re-engineered also.
Not much RV left by the time you get done, is there?
Anyway, I am not an engineer, so my thoughts are only a SWAG, but you get the idea. Pretty sure I have missed a few things.
Thanks for the chance to do a bit of mental exercise
As I said before, welcome aboard.
Flyfalcons
Well Known Member
I don't even think my Lear can do 1000fpm on one engine and it does 5000+ with both operating. A piston plane doing 1000fpm on one engine just isn't going to happen.
cawmd82
Well Known Member
Pots and kettles?
Hmmmm......Isn't the state of Wyoming symbol a Cowboy??
Sounds like a fun ride if you can thru the details-Maybe twin 0-340s would bolt up.
Hmmmm......Isn't the state of Wyoming symbol a Cowboy??
Sounds like a fun ride if you can thru the details-Maybe twin 0-340s would bolt up.
Yeah, but don't blame me. In the thirties when tourism was really getting rolling here, the mayor of Cheyenne told everyone to dress more like "cowboys". He said "we don't want to just look like a bunch of farmers". Could be we took it too far. Sometimes its like living in a bad episode of Gunsmoke.
Cessna Mix Master or Defiant
I suggest you purchase a Cessna Mix Master or a Rutan Defiant. The Defiant is a really nice plane, but the completion rate is abysmal. There are very few completed because it is such a huge project.
It does perform like you want, though. Check out the original video:
http://www.youtube.com/watch?v=KhYaDFLDoEQ
The takeoff with the front engine stopped is pretty impressive.
Steve Sorenson and his brother took one from California to Australia via Hawaii.
http://blog.travelpod.com/travel-blog/twin_puffin/1/tpod.html
I suggest you purchase a Cessna Mix Master or a Rutan Defiant. The Defiant is a really nice plane, but the completion rate is abysmal. There are very few completed because it is such a huge project.
It does perform like you want, though. Check out the original video:
http://www.youtube.com/watch?v=KhYaDFLDoEQ
The takeoff with the front engine stopped is pretty impressive.
Steve Sorenson and his brother took one from California to Australia via Hawaii.
http://blog.travelpod.com/travel-blog/twin_puffin/1/tpod.html
cawmd82
Well Known Member
Carbon replica O2 A
http://www.aviationenterprises.us/replica0-2askymaster.html
So maybe this is what you really want.....
http://www.aviationenterprises.us/replica0-2askymaster.html
So maybe this is what you really want.....
I am sure you will be the first
I'm sure you will be the first and the probability that you will fail is great but that's what makes people special. Twin booms have been popular since the beginning of powered flight so I know you can make a flying twin boom twin engine centerline thrust airplane using many design features and actual parts from an RV. If you rise to the challenge and are successful I am certain you will be the hit of every aviation magazine, every airshow you attend including Oshkosh because IT IS HARD! Good luck with your decission.
Bob Axsom
I'm sure you will be the first and the probability that you will fail is great but that's what makes people special. Twin booms have been popular since the beginning of powered flight so I know you can make a flying twin boom twin engine centerline thrust airplane using many design features and actual parts from an RV. If you rise to the challenge and are successful I am certain you will be the hit of every aviation magazine, every airshow you attend including Oshkosh because IT IS HARD! Good luck with your decission.
Bob Axsom
Toobuilder
Well Known Member
Caution: Thread Hijack In Process...
Delete... Started a new thread
Delete... Started a new thread
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Yeah, it was awesome!
David Paule
Well Known Member
I don't know what your experience level is, but if it doesn't include relatively long cross country flights using instrument flight plans, it might be a good idea to get that sort of experience before committing to the very large effort that would be required to successfully bring off a project of this magnitude.
In general, you're probably facing something in excess of 5,000 hours to design and build an aircraft like you're hoping to fly. That's a huge time commitment, and if you simply flew 5,000 hours at 150 mph, that's three fourths of a million miles. If a long cross country flight for you is 1,250 miles each way, that represents 300 round-trip flights. If you made one such flight each month, that's 25 years of flying.
And it's not simply a matter of sharpening the pencil and digging in. As has been pointed out, the performance and handling criteria you desire is difficult to achieve.
Think it over. If you want a good project, and a safe single-engine airplane with excellent performance and IFR capabilities, you've come to the right place.
Dave
In general, you're probably facing something in excess of 5,000 hours to design and build an aircraft like you're hoping to fly. That's a huge time commitment, and if you simply flew 5,000 hours at 150 mph, that's three fourths of a million miles. If a long cross country flight for you is 1,250 miles each way, that represents 300 round-trip flights. If you made one such flight each month, that's 25 years of flying.
And it's not simply a matter of sharpening the pencil and digging in. As has been pointed out, the performance and handling criteria you desire is difficult to achieve.
Think it over. If you want a good project, and a safe single-engine airplane with excellent performance and IFR capabilities, you've come to the right place.
Dave
flyeyes
Well Known Member
There may be an easier path.
Don Stewart, designer of the Stewart Headwind and the Foo Fighter, has a patent on a "dual-pack" twin engine installation with counterrotating props on concentric shafts.
The twin Cozy was a one-off adaptation of his patent.
His intended market was Cessna 172 airframes, with their large firewalls. A pair of continental O-200s, one on top of the other, pointing in opposite directions, each driving its own propeller on concentric shafts. 200HP and twin redundancy.
A pair of O-320 or O-360s on an RV-10 would be interesting
Don Stewart, designer of the Stewart Headwind and the Foo Fighter, has a patent on a "dual-pack" twin engine installation with counterrotating props on concentric shafts.
The twin Cozy was a one-off adaptation of his patent.
His intended market was Cessna 172 airframes, with their large firewalls. A pair of continental O-200s, one on top of the other, pointing in opposite directions, each driving its own propeller on concentric shafts. 200HP and twin redundancy.
A pair of O-320 or O-360s on an RV-10 would be interesting
