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RV-12 as a Taildragger

T

todehnal

Well Known Member
There have been a few posts here and there about the RV-12 as a taildragger. I think that this discussion deserves just a little more attention.

First, most LSAs will probably fly out of small strips, many of which will probably be grass. Nothing works better on a grass runway than good old fashioned taildragger and nobody does it better than Van. Just like the RV-9, Van is reluctant to put the R & D into a project unless he sees a high interest and potential for increasing kit sales.

The RV-12 needs to be offered as a taildragger!

Some of the comments that I have seen of this site suggest that the 12 would be difficult to convert to a taildragger. One reason stated is that the mains are designed to be supported by the front spar and that a taildragger configuation would require engine mounted gear. I remmember when the old Tripacers were converted to Pacers. All they did was basically to reverse the gear legs, which canted the gear forward and now they were taildraggers.

Consider designing gear legs for the 12 that attached to the same point only were swept forward to the required position to shift the three point CG far enough aft to place adequite weight on the tail and relieve the weight from the nose. Now, all that would be needed is a tail wheel mounting and differential braking.

It is amaizing what a determined builder can come up with.

All comments appreciated. I think that we can make this a viable option for our RV-12s

Tom
 
:) The RV12 has removable wings therefore the landing gear is not attached to the spar in typical RV fashion. What is depicted on the Vans website shows there is no engine mount structure that would support landing gear loads. My friend who is an engineer has looked at the RV12 as designed in it's present configuration and she has said it is not possible to make a taildragger out of this aircraft as it is today. Also she said the Tri-Pacer gearlegs will not work simply turned around and that the gearlegs used to convert to taildraggers are a different design to accomplish the conversion.(the myth of turning the gearlegs around has been told many times and simply is untrue) ;) Caitlin
 
Gear Attachment

I said spar, but I didn't mean wing spar. The main gear appears to be attached to the center section carry through spar, eliminating the need for gear boxes. That would have no effect on the removable wings and doesn't negate shifting of the main gear CG aft far enough to make it a tail dragger. Many popular trigear configurations have been converted, including the grumman A1s, Cessna 150s and 172s, even the Zenair! Someone even made an RV retractable! So, what would stop you from making changes during the build process of the RV-12? Consider all of the weight that you would remove by eliminating the nose wheel, along with all of the positive steering mechanism. That should provide ample opportunities to add the required structure to make the change.

Someone will do it! Watch and see.
 
FWIW, I'm with you. I guess it's not surprising that there seems to be a lot of designs that fit what "everyone" wants. In other words, two place, side by side, tri-gear.

Hopefully, this is just the entry model for everyone, and there will be some other models that will come available as well. I'd personally like to see a tandem taildragger, but I'll just have to be satisfied with my current RV-8 project for now :D

Rusty
 
13brv3 said:
Hopefully, this is just the entry model for everyone, and there will be some other models that will come available as well. I'd personally like to see a tandem taildragger
Rusty
Click to expand...

I'm all for that Rusty.
 
:p Everyone has their dream and yes I will agree that maybe a talented individual might someday make a taildragger RV12, but the task will be greater than the afore mentioned conversions 150, 172 etc. You must realize of course that the progression was the other way around. The Cessna 150 lineage was the taildragger Cessna 140 and the 172 was born the Cessna 170, also a taildragger. When you get a chance to see photos or the actual RV12 up close, I believe you will agree that to make this aircraft a taildragger will encompass a complete redesign, not just turning the gear around or even moving it forward. :eek: Caitlins engineering friend :eek:
 
todehnal said:
The RV-12 needs to be offered as a taildragger!
Click to expand...

A Taildragger? Now that's just CrAzYtAlK! No way, can't be done! Too much work, everything's in the wrong place. Why even bring it up?

Jeez Tom, have you lost your mind???

( :rolleyes: sarcasm, read on... :cool: )

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todehnal said:
It is amaizing what a determined builder can come up with.
Click to expand...

You got that right! If it can be done, someone will do it. If it simply can't be done, now that might take a little bit longer BUT....
 
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Don't expect Van to design it. He got "burned" on the 9 and won't recoup the redesign cost of turning it into a TW. He said he won't do the R&D for that on the 12.
 
Paul Thomas said:
He got "burned" on the 9 and won't recoup the redesign cost of turning it into a TW.
Click to expand...

What design cost??? He moved the main gear a little from the RV7 mains. That means a slightly different engine mount and gear legs. All the rest is the same as an RV7.

Vans has quite a few RV9 finish kits in the pipeline and there are quite a few flying. Probably more RV9's flying then some other well known kits on the market. All that for the cost of a new engine mount and gear legs. Sure sounds like a good investment me to.
 
Good solid interest and "can do" attitude like these previous posts are just the type of publicity that will get the job done for us who are willing to got the extra mile to get what we want. I'm a builder and and flyer, not an engineer, thus, I will certainly need some help in the design phase, but I am ready and willing to go there!!

Tom
 
First, I apologize for reviving this old discussion.

I've been looking into this and am convinced that it can be done. It would add considerable weight, probably in excess of 30 pounds, even after eliminating the tricycle gear.

The aircraft would need to be higher off the ground because the horizontal tail is relatively low and would need about 24 inches, more is better, to the ground back there. That pretty much means that some sort of ventral fin mounting for the tailwheel would be necessary - there's good reasons why not to move the horizontal tail higher.

The relatively low horizontal tail position means that an RV-12 taildragger will never be a real bush plane. Damage that and you're screwed, and 24 inches clearance means that brush contact is inevitable sooner or later in the bush. Guess how I know this....

Since the tail wheel would need to be steered, some interconnection between the rudder or rudder controls and the tailwheel would need to be created and installed. I haven't even looked at how to do that yet.

It would need at least a partial new bulkhead forward of the aft bulkhead to help handle the tailwheel mounting loads.

The major new structure would probably go in the area between the F-1202F and F-1203A bulkheads. There are simple and there are complex ways to manage it, but it's important to remember that they all carry the same loads. The trade-offs are complexity and bulk (and build time) versus weight.

In any case, there would be some structure extending up the sides of the cabin. I don't know yet whether there's room for that or whether it would protrude into the cabin too far. Comments?

Since all this new main gear structure would be built into the aircraft during initial assembly, rather than being retrofitted, some abusive changes in the construction sequence will be involved. That all needs to be thought out - at this point I see no show-stoppers there, though, just the usual screaming when the builder needs to redo something that became out of sequence.

An unknown issue is whether the new main landing gear, forward of the wing, would adversely affect performance or stalling characteristics. There's some experience to suggest it could.

Finally, the aircraft will be an E-AB non-RV airplane rather than an RV E-LSA airplane, and that would affect its resale value as well as the taildragger configuration.

Bottom line, you can do it with a lot of extra work. The plane would be heavier, have less room in the cockpit, be harder to get into and out of, and would be a perfectly usable taildragger.

If there are other aspects of the change that I haven't covered, I'd appreciate it if someone would chime in and expand on them.

Thanks!
 
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oceanbird said:
I think that the RV-12 is a great airplane as it is, and it was designed as
a whole system, so better don?t mess with it.

In my opinion, it shows the future of Van?s kits. So far, ok, but..

I am convinced that Van?s, given its history and tradition, SHOULD
design a taildragger, tandem seat version of the -12. Call it RV-14
if you want, why not? The LSA version of the RV-4?

A modern kit like the -12, 912 engine, capable of light aerobatics, and
LSA compliant..Why not? Others are doing something similar with great
success( sonex).

Anyone likes the idea?

Maybe we could convince Ken Krueger to give it a thought? :rolleyes:
Click to expand...

AFFIRM I like it!
 
Ok - let's give Van's a few suggestions

Let's ask Van's to consider a few RV-12 changes (major and minor).

I would like my next LSA to have an American engine - ie, Lycoming. Then it should have Sky View and G-696. Here's a few other pretty obvious possibilities:
A. Taildrager or tri-gear.
B. Other optional engines.
C. Tandem.
D. Side by side.
E. One seater.
F. Removable wings or not.
G. Larger fuel tank or tanks.
H. BRS?

Love the basic RV-12:rolleyes:
 
LSA RV-4

oceanbird said:
Snip....I am convinced that Van?s, given its history and tradition, SHOULD design a taildragger, tandem seat version of the -12. Call it RV-14 if you want, why not? The LSA version of the RV-4?

A modern kit like the -12, 912 engine, capable of light aerobatics, and
LSA compliant..Why not? Others are doing something similar with great
success( sonex).

Anyone likes the idea?

Maybe we could convince Ken Krueger to give it a thought? :rolleyes:
Click to expand...

I've likewise posted this idea before. This is my dream kit. However, I too would like to see the O-233... or the Jabiru 3300. I've flown the 12... and it is sweet. However, as much as I like the little bird, it just doesn't "grab" me. She's the homely little sister. :p

Happy little life changing additions (TWINS) have delayed my ability to build... so in the mean time, I'm hoping Van's will come up with the industries first SEXY LSA. :D

PLEASE?!!

DJ
 
Homely...

Phyrcooler said:
I've likewise posted this idea before. This is my dream kit. However, I too would like to see the O-233... or the Jabiru 3300. I've flown the 12... and it is sweet. However, as much as I like the little bird, it just doesn't "grab" me. She's the homely little sister. :p


DJ
Click to expand...

She doesn't look too bad once she gets a little makeup on... ;)

[url=http://tonytessitore.smugmug.com/RV-12-Project-N577RV/Color-Scheme/11643931_KpABS#977168359_vBdja-A-LB][/URL]

Tony
 
Tony_T said:
She doesn't look too bad once she gets a little makeup on... ;)

Tony
Click to expand...

She is looking good Tony...

There's a lot of decent looking women out there... but you know how it is when one just has "the look". For me... the 12 is decent... but I'm looking for a shapely little (LSA) tandem seater to wink at me! Especially if she can do acrobatics! :eek: I still am leaning towards the 12 absent my dream girl sliding up to the bar. ;)

(Hopefully my wonderful wife understands it's all just airplane talk!)
 
KatieB said:
Hey hey watch it there!! If these ain't sexy LSAs, then tell me what sexy is! (if it's sexy metal LSAs you want, OK fine...)
www.usjabiru.com
www.flylightning.net
Click to expand...

Cessna knockoffs just don't do it for me. The Lightening is nice looking but no thanks.

There was an Italian made tandem, open cockpit LSA with the Rotec radial engine that was really sexy, in a 1920's sort of way. If you have to go slow, go in slow in style. Unfortunately I can't remember the name of it and couldn't find it on the net.
 
Getting back to the topic of this thread for a moment, the crosswind capability of the RV-12 is only 11 knots. That suggests that there might be limited rudder control power available as a taildragger, and that the taildragger crosswind component might be even lower.

That would be a distinct operational inconvenience.

I've worked out the main gear structural changes for a taildragger and it's certainly doable. Haven't worked out the ventral fin and tailwheel attachment yet. Getting rudder control to the tail wheel is a little more complicated than I'd thought it would be, but nothing particularly annoying there, just more parts.

Just for emphasis, these and all the other negative factors I've mentioned earlier here (8-31) would be present if the RV-12 were converted to a taildragger. There might be more difficulties that I haven't thought of, too.

But it can be done.
 
David Paule said:
Getting back to the topic of this thread for a moment, the crosswind capability of the RV-12 is only 11 knots. That suggests that there might be limited rudder control power available as a taildragger, and that the taildragger crosswind component might be even lower.
Click to expand...

I am curious where you got the 11 kts # from?

I have made takeoffs and landings in an RV-12 with a 15 kt direct left cross wind and still had more than enough rudder. Mostly standard techniques used. The takeoff is actually the limiting factor with a left side cross wind.
With the engine torque left turning tendency and the weather vanning tenancy combined, coupled with a free castoring nose wheel, it takes a bit different technique from what most people are used too. Lifting the nose wheel as early as possible reduces the amount of rudder required.
 
rgmwa said:
Scott,
I'm not David Paule, but it's stated in the POH on page 3-3. "Maximum direct crosswind component 11kt"
Click to expand...

I didn't remember that was in there.

Basically it means that was the maximum that had been operated in. Same as Cessna POH's always say "Maximum demonstrated". We know for sure it can do this much....
 
rvbuilder2002 said:
I didn't remember that was in there. Basically it means that was the maximum that had been operated in. We know for sure it can do this much....
Click to expand...

... but it's nice to know it can do a bit more :)

Maybe the POH can be amended to 15kt based on your experience?
 
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