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Another Trailer Concept

KThorp

Active Member
After exchanging a couple emails with Dr. Dave I made this trailer concept #3:
358g5xjy56.jpg

I posted multiple images and an animation here:
http://www.box.net/shared/8s6psmv2l1

Notes:
  • I saved the animation in Windows Media (WMV) and Quicktime. The WMV is a little higher quality, if you can play it.
  • The goal was to minimize size, weight an wind resistance. This one is not the "super hangar on wheels".
  • I'll add the trailer tongue & axle
  • The wings will obviously need to be supported with some type of padded rack
  • I don't know if we can squeeze the RV-12 gear between the trailer tires. They measure 84" outside, and the trailer cannot be wider than 102" in most states. That's only 9" per side for the trailer wall, wheel & fender. The alternative would be to put the deck above the wheels, making the trailer much taller.
  • Those small doors near the wheels are for easy access for tie-downs.
The previous 2 trailer concepts can be found here: http://www.box.net/shared/2kjtn56l6b
 
I'm curious how much the trailer + airplane will weigh? It seems to me you'd need at a minimum a 1/2 ton pickup to tow?
 
Another trailer concept

You are headed in the right direction, a trailer for many will make safe storage possible and afforadable. I think you may find that the wings will want to be on each side of the trailer so that they ride into the trailer on wheeled fittings that lock into the trailer when they are in place. I am also concerned about the "Dog Houses" for the elevator as the natural movement of the aircraft on its gear will cause a lot of movement in that area which could cause damage to the elevator, perhaps some kind of tail end vertical lock stand could resolve it.

The glider/sailplane people have mastered trailers and wing removal, if you get the chance please go to a glider field to see the trailers they use for the better glass ships. You will see much of interest.

I also see a need for a simple open trailer that can be used to store the plane on for storage in the back of existing hangars or in the home garage where weather protection is done by the building and easy transportation to the ramp at the airport is the only need. Again a trailer like the kind of open trailers used by the glider world for gliders like the Schwitzer 1-26 would serve very well and would not cost much.

Keep up the good work.

Best regards,
Vern
 
It looks a bit like the trailer they used to sell for the BD-5.

The one thing I don't like is putting the wings on the trailer floor. There are a few reasons for this; first, a rock or stick that gets tracked up into the trailer will put a dent in the wing and second, the top wing will be bouncing on the bottom wing and they are not designed to take that kind of load.

There is another problem with the current design, how are you going to "slide" the wings in place and secure them after you get the fuselage in the trailer?

It might be better to make some type of rack and/or straps to support the wings on the side of the fuselage, leading edge down. Then you can put the wings in before winching the fuselage in place.
 
One other question...

How wide is the HS on the -12?

Isn't the max roadable width w/o wide load permits 8-1/2 feet in most states?
 
Stab. Clearance
The stabilator is 96" (8'), So I added 3" to either side. This might not be enough room to allow for movement on a bumpy road. We could support the tailcone but that might cause damage. Dr. Dave suggested wide open slots, leaving the stab. & rudder tips exposed (perhaps with strap-on padded sleeves). Then for fixed storage have hard-shell covers.

Horiz. Wing Storage
Concepts 1 & 2 have vertical wing storage. This concept #3 was suggested by Dr. Dave. It allows for a lower & more curved roof - saving weight & helping crosswind handling. The wings definitely wouldn't be on the floor or stacked directly on each other. Perhaps the bottom wing is placed on a padded cradle on a track, then a padded spacer is set on it, then the top wing. Finally the assembly is slid forward & strapped down.

Weight
The RV-12 weighs 750 lbs. If we keep the trailer under 1,250 (2,000 lbs. total) then most small trucks and many cars will be able to pull it. But to keep it under that weight it can't be built like most 20' cargo trailers, which typically have dual axles, weigh 3,000 lbs empty and have a 7,000 lb. capacity (10,000 GVW). I saw a cargo trailer at Sun n Fun with what looked like a vinylized cloth shell. Very light, but I think a hard shell would be a little more protection.
 
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Kevin,

Very very neat!

With the RV12's empty weight of 740 (or reported 720) and 20 gal of gas the total load is about 850 or so easily under 1,000 with other stuff. So a total tow weight of under 3,000 lbs is within reason, and within mini-van capability. The limiting factor for towing then becomes wind resistance, which your design works toward minimizing, while allowing in trailer maintenance (like oil changes) and fueling on the way to the airport.

To aid in reducing the overall width, it might be possible for the aircraft's wheels and the trailer wheels to share the same track. This would allow for larger wheels and a low overall height. Using low-rider technology, jack the trailer wheels away from the trailer (i.e. raise the trailer) to provide a flat bed for loading, and then lower the trailer for towing. An air pump and two air bags should do it.

The load sequence. Start the aircraft in until the main wheels are up to the rear trailer wheel fenders. Raise the trailer bed thus putting the top of the trailer wheels below the bed. The trailer wheel fenders/wheel buckets moves with wheels and their top surfaces fills the holes in the trailer bed, providing a smooth surface for the aircraft main wheels to roll on. Mover the aircraft fully forward. Lower the bed, the top of trailer wheels are now again above the trailer bed and the fender buckets seal the inside from the outside. The forward fenders around the trailer wheels also chocks the aircraft wheels in the fully forward transport position. Now roll the the loaded wing dolly under the rear fuselage and lock it in place.

Kevin, thanks for your work on this.

-Dave
 
just a question.

does anyone know how Partain's trailered the red one to Sun N' Fun last spring? What did they use? What was the config? Or do they use large tractor equip and 40' trailers?

Pete
 
Before anyone gets too carried away, check with Van's. When I was there several months ago, Ken mentioned they are considering providing a trailer kit--or maybe just plans.
 
It depends on...

Just to confirm, the max USDOT width is currently 102".

"I don't know if we can squeeze the RV-12 gear between the trailer tires. They measure 84" outside, and the trailer cannot be wider than 102" in most states. That's only 9" per side for the trailer wall, wheel & fender."
......
Just my .02

...the state in question. Some have an 8 ft limit (AZ and OR are examples) when you are off Federal highways.

Details are here...

http://www.wecamp2.com/size.html

I presume you would have trouble registering it in a state with a narrower limit.

State rules trump Federal rules once off the freeways....:)
 
RV-12 Trailer

I applaud you all for getting the (trailer) ball rolling again here and I am hopeful that one or more trailer building companies (maybe one that already builds trailers for gliders) is watching this as it evolves. If so, maybe they will share with us some of their expertise. :cool:

I have hundreds of hours towing an Airstream and a boxier house trailer on the freeways, interstates and locally. Towing this large a trailer is not for everyone and not for every car. Many cars are just not stout enough to tow a trailer of any size.

It is wise in my opinion to try to streamline the RV trailer as much as possible. This makes it easier to control in a wind and when being passed by a truck or bus, etc. Also, streamlining it will make a significant difference in fuel economy in my experience. This could be done in aluminum without the fancy compound curves of the Airstream by keeping the front and back ends rounded top to bottom only - not top to bottom (and) front to back like the Airstream. Hope that makes sense!

I would like to see an aluminum exterior with pulled rivets into preformed arch shaped inside formers. This makes it a little longer but the front end at least, could be used for storage of tools, gas, etc., etc.

The RV-12 trailer will be wide and long in order to enclose the airplane. This aircraft is not a lot smaller than the RV-9!!! I recommend that the trailer be either 8, 8-1/2, or 9 feet wide with options on this dimension depending on your states of intended use.

Don't even try to make it form fitting to enclose the empennage. You can't have enough room inside no matter how wide it is and those wings are delicate when mishandled. How about a door up front on the right side?

Considerable thought must be given to the design of the trailer. A weight and balance and a gross weight must be calculated and accurate in order to have a good handling unit - just like an airplane. The placement and number of trailer wheels, type of springs and shock absorbers will depend on the weight and placement of the load and accessories such as gas, tools, spare tire, etc. Also consideration must be given to the 'tongue weight' in order to have good road handling.

It is easy to build a trailer that looks great on paper but is no good on the road.

Cost is a real consideration - I have no idea what $$$$$ we are talking about here but it won't be cheap. Try to keep it as simple as possible. I am hopeful that Van's or someone else will sell an affordable trailer frame that I can pick up at Van's and tow home with the RV-12 kit strapped to it. Then, I'll build the sides and front and back ends at home - aluminum all the way of course with pulled rivets - although I must admit that the exterior surfaces of this trailer are a natural application for the dreaded 'f' word - (fiberglass). Compound fiberglass ends, sides, and rounded top (like an Airstream) are pretty easy to do in fiberglass. And aluminum framework - Hmmm! Thanks again for this discussion.
 
Trailer towing consideration

To make the trailer stable for towing, make sure that the weight is forward of the wheels or the trailer will sway side to side when towed at higher speeds. I almost lost a trailer because it was loaded with the weight too far aft.
 
I emailed Vans and they did say they are considering designing an RV-12 trailer. But that was almost 2 years ago.

I just added a "Concept 4" folder: http://www.box.net/shared/2kjtn56l6b

dhxbzpqfzv.jpg

Notes:
  • This version is 88"-90" wide, so it's legal on all roads in all states.
  • It has flat panels so could be easily fabricated from sheet metal or plywood
  • The "pop-top" roof aids in loading/unloading but also could be a nice shady area to sit.
  • I show what looks like 3 hydraulic cylinders to lower the aircraft. They'd be almost impossible to syncronize. Perhaps use 3 jack screws connected by a timing belt - like this. Electric or hand-crank. It shouldn't take too long to lower 750 lbs. 1 foot.
  • Once again I made the stab slots too small. The "caps" could be made from closed-cell foam rubber. Then you have protection from rain & bugs, and if the stab bumped it, the cap would flex.
 
flat tires?

Kevin, I enjoy your presentations of the various concepts. Would you model combinations of flat tires, potential flex of the nose gear strut, and some movement (rotation left and right) of the nose gear fork to to show the potential movement of the tail? Thanks. John.
 
One fab. approach

If you are after a square box... a welded frame of standard 1 inch sq. 0.065 thick steel tubing with an alum. (or other) sheet covering is an easy way to go.

Make the box light and bolt it to a more substantial running gear frame so that the pulling loads go directly to the wheels and are not transmitted through the box structure.

I built a 30 ft sailplane trailer this way.... the running gear was made by a local utility trailer builder - I just asked for a flat 4 x 8 ft base frame (his standard size) with a 12 ft. tongue.

If you build this way, you can get a strong trailer that is light. A monocoque structure is difficult to design correctly, and I have seen many home built sailplane trailers fail - usually at the frame/axle joint or tongue/box joint. Make the tongue go all of the way back to the running gear.
 
Glider Trailer Link

If you cannot get to a glider field and want to see what a glider trailer looks like inside and outside, the following link will show you a Cobra Glider Trailer.

http://www.wingsandwheels.com/Cobra.htm


I have a Cobra Trailer for my Discus-2T and I am very pleased with the ease of loading/unloading and the roadability of the trailer with the sailplane. We have several sailplane owners at Texas Soaring Association (TSA) Gliderport who assemble and disassemdle their sailplanes every time they fly. The trailer provides protection from high winds and hail which happens fairly often in the Dallas/Fort-Worth area.

If you are in the Dallas/Fort-Worth area, drop me an e-mail and I'l show you our very active club and our sailplanes. The TSA link is:

http://www.texassoaring.org/

Bob Kibby
 
RV-12 Trailer

I agree with Gil about the framework and think that we are making good progress in this thread. After seeing the price range of the really nice sailplane trailers above, I will be forced to build my own - at least the 'top'.

Hey Van's - how about a 'top' kit, with a few variations, in order to fit several different basic frame sizes and widths? The lower 3 or 4 feet of the sides need to be pretty rigid in my opinion but then how about fabricated aluminum arches over the top, rounded (hopefully not pink) fiberglass front and back, and aluminum sides? All pulled rivets. I'll bet that two persons could build that type of 'superstructure' in a day or two!!! Paint it now or later or not!

It is necessary to do some engineering when designing any trailer. I'll bet that there are quite a few trailer frame manufacturers throughout the USA and elsewhere who would be happy to sell us the basic framework. I'll bet that many of these manufacturers have already done the engineering reference gross weight, suspension, number of wheels, surge brakes, load placement, etc.

If we choose to purchase only the frame and running gear then we can finish the 'top' ourselves or hire it done. Before I design my sides and top, I'll visit sailplane flying fields and talk to those who really do use their trailers on the road. Hopefully, I'll know a lot more about trailer design after that.

I want my trailer to have a lot of 'wiggle room' inside both for the aircraft and so that I could do basic maintenance there if I have to. So it'll likely be slab sided with a rounded top, front, and back. Towing a trailer about 20'-24' oal isn't a piece of cake and I want my trailer to be as roadworthy as possible.

Like many of us, I have a year or two to see what develops so I'll be watching this thread with great interest. Hope that Van's or some US trailer manufacturer is listening!!!
 
DIY trailers

I agree with Gil about the framework and think that we are making good progress in this thread. After seeing the price range of the really nice sailplane trailers above, I will be forced to build my own - at least the 'top'.

Hey Van's - how about a 'top' kit, with a few variations, in order to fit several different basic frame sizes and widths? The lower 3 or 4 feet of the sides need to be pretty rigid in my opinion but then how about fabricated aluminum arches over the top, rounded (hopefully not pink) fiberglass front and back, and aluminum sides? .....

It is necessary to do some engineering when designing any trailer. I'll bet that there are quite a few trailer frame manufacturers throughout the USA and elsewhere who would be happy to sell us the basic framework. I'll bet that many of these manufacturers have already done the engineering reference gross weight, suspension, number of wheels, surge brakes, load placement, etc.

If we choose to purchase only the frame and running gear then we can finish the 'top' ourselves or hire it done.
......

This is an example of a US made "running gear" for a DIY sailplane trailer.
Price was around $1600 in 1999 - I don't know if they are still in business.

frame.jpg


...my suggestion to make the tongue connect to the wheel sping mounts still stands...:)

This running gear is combined with a fibreglas top to make a traditional sailplane box type trailer. The web site claims over 40 have been built.

trailers.jpg


For a regular 15m sailplane, the box is just over 26 ft. long, but usually a mere 4 ft. wide.

My sailplane is around 600 pounds empty, so weights are quite comparable to a new LSA.

The Komet style (clamshell openeing) trailer is nice, but somewhat more difficult for a DIY effort. A lot of design is needed to get a good, and solid, working mechanism to keep the top open and closed firmly. The clamshell also does not add to the torsional rigidity of the final trailer.

An elongated box is much easier to design and build, as in the original proposed designs.
 
From a couple suggestions by Dr. Dave I created a tilting deck "RV Trailer Concept #5": http://www.box.net/shared/2kjtn56l6b

mpo8o9msso.jpg


Notes:
  • I didn't show the tilt mechanism. It can be a pneumatic cylinder, electric or even hand-cranked
  • There should be some type of hinged plate over the open wheel wells when the deck is tilted up
  • I show foam rubber stab. caps. For static storage these can be replaced with metal or fiberglass caps
  • The shell is curved for streamlining, but there are no compound curves, so the sheet metal fabrication shouldn't be too difficult
I agree the construction should be similar to sailplane trailers. Does anybody make them in the USA?

We could make the trailer box much smaller if the RV-12 didn't have a prop, landing gear or stabilator. Are those part important? :D
 
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US makers

....I agree the construction should be similar to sailplane trailers. Does anybody make them in the USA?
....

Minden Fabrication, Minden, NV made a lot of alum. monocoque ones...

http://web0.greatbasin.net/~hcsoaring/pages/trailers.htm#Top

Their glider FBO business closed, but I'm not sure about the trailer business.

The previous DIY picture was from Gaines Composite trailers...

http://www.mindspring.com/~composites/trailer.htm

...but the web page is from 1999, don't know if they are still in business.

One of the items that did in the US sailplane traler business was the advent of "roll-on-roll-off" ships delivering VWs and BMWs to the US. Buying a german trailer and having the trailer become the shipping container on one of these ships was cheaper and easier than shipping multiple sailplanes in standard shipping containers... along with a drop in soaring and an increase in price of new sailplanes....:(

One option not yet mentiones, a bit less desirable, but cheaper, is an open trailer.

If a trailer design can be made to fit into a single car garage spot, then just taking it home might be OK. I did this for over 5 years with my wooden Duster sailplane - its trailer had a retractable tongue to enable it to fit into a single car stall.

Trailer design becomes much simpler, as can be seen on the 1-26 trailers.

A lot are tilt bed, like this one...

525s_trailer.jpg


Pic of 1-34 trailer - same thing, just longer....

6.jpg
 
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It would be so cool if Vans provided a kit for the trailer also?

I bet a ton of people are going to buy the RV12 because they can trailer it to the airport for the summer or even for the just the weekend.

I know in Europe the cost of hangers and even tie downs are ridiculous and hence I bet that combined with fuel costs will push a lot of folks towards the RV12. It might be a good move to provide a trailer kit as it would trump most of the other LSA type products that do not.

Hugh.
 
Before a trailer manufacturer got involved I'm sure they'd want to see the sales figures of the RV-12. Then they'd have to estimate what % of those customers would buy a trailer.

With the current euro/dollar exchange rate a US-built trailer would be a bargain over there (the opposite of the current Rotax pricing situation).
 
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Thanks Gil, for digging up the photos & info on the sailplane trailers.

For cost & weight savings it would be great if the RV-12 landing gear could fit between the trailer wheels. This might be possible. I measured my 12" boat trailer tires & was surprised they were only 5 3/4" wide, offset 2" away from the frame. Can that offset be less? Is 1 1/4" enough?

Here's one possibility:
RV-12 landing gear (outside width): 84"
Wiggle room inside trailer: 1 1/2"
Trailer frame (1 1/4" per side): 2 1/2"
Wheel offset (1 1/4" per side): 2 1/2"
Wheel width (5 3/4" per side): 11 1/2"
Outside width of trailer "box": 88" or 7'-4"
Total width of trailer: 102" or 8'-6" (legal in most states)​

My 12" boat trailer tires are rated at 1,045 lbs (2,090/pair). An RV-12 with a full tank weighs 860. That leaves 1,230 lbs for the trailer & other gear. One of those enclosed sailplane trailers weighs 995 lbs, so it is possible to build a trailer that light, but it might be good to have something with a little more "beef".

I've seen 13" trailer wheels with an advertised rating of 1360 lbs (2,720 lbs/pair). The rim width is 4 1/2" but nobody publishes the tire width.

Does anyone have 13" trailer tires they can measure?
 
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RV Trailer Concept #5"

Kevin, I really like this idea. It would allow me to use a readily available boat trailer, fully galvanised and with a winch installed. A fairly light tilting floor could be used, provided when the floor was levelled the wheel footprints could be be supported by structure built on to the trailer frame. The compound curves of the cover seem to lend themselves to a fibreglass shell.

Rod
 
Wing wheel barrel

Since I'm planning to store my broken down (wingless) RV-12 in a shared hanger at KSRQ with the owner of a Cirrus SR20, I was surfing the internet looking for a method of removing and reattaching the the RV-12's wings all by my lonesome.

I think I've found the perfect system. :) :) :)

Let me know what you gentlemen think.

Be sure to click on "Click here to see how to use the cart, step by step" ... at the bottom of the attached web site.

http://www.mmfabrication.com/SPRC.htm
 
Since I'm planning to store my broken down (wingless) RV-12 in a shared hanger at KSRQ with the owner of a Cirrus SR20, I was surfing the internet looking for a method of removing and reattaching the the RV-12's wings all by my lonesome.

I think I've found the perfect system. :) :) :)

Let me know what you gentlemen think.

Be sure to click on "Click here to see how to use the cart, step by step" ... at the bottom of the attached web site.

http://www.mmfabrication.com/SPRC.htm

Cool find Jerry. I was mentally designing something similar a few weeks ago... but it looks like there is no need to reinvent the wheel... or the wheel barrow as it were.

DJ
 
Since I'm planning to store my broken down (wingless) RV-12 in a shared hanger at KSRQ with the owner of a Cirrus SR20, I was surfing the internet looking for a method of removing and reattaching the the RV-12's wings all by my lonesome.

I think I've found the perfect system. :) :) :)

Let me know what you gentlemen think.

Be sure to click on "Click here to see how to use the cart, step by step" ... at the bottom of the attached web site.

http://www.mmfabrication.com/SPRC.htm

Hi Jerry,

That is the right direction, but the machine will need to be changed by the maker to accomidate the RV-12 wing which has a much longer cord and it will not be practical to jack the fueslage of the RV-12 so some adjustment in the wing device will need to be made. I think that there will be many of the RV-12 builders who would use such a system as it would be paid for in only a few months of hangar rent and would make some airports with long hangar waiting lists available now, with out having to park outside.

Best regards,
Vern
 
The wing holder....

Hi Jerry,

That is the right direction, but the machine will need to be changed by the maker to accomidate the RV-12 wing which has a much longer cord and it will not be practical to jack the fueslage of the RV-12 so some adjustment in the wing device will need to be made. I think that there will be many of the RV-12 builders who would use such a system as it would be paid for in only a few months of hangar rent and would make some airports with long hangar waiting lists available now, with out having to park outside.

Best regards,
Vern

...can be made adjustable in height as mentioned above.

The two examples (somewhat pricey...:)...) on this page show one that is manually adjustable, and one that is motor driven in height via a wireless remote control...

http://www.wingsandwheels.com/page47.htm
 
Revisiting This Old Thread - RV-12 Wheel Weights

OK - as of 2023 we know that an RV-12 CAN fit in an enclosed trailer. A recent thread on the RV-12 forum had photos of two trailer examples. I wonder how many more enclosed RV-12 trailers there might actually be.

I am working with a major trailer manufacturer on a custom 22-foot plus aluminum RV-12 trailer that will have an empty weight without fitments of about 3,400 pounds. So far the required door and box width (and heights) can work within 102-inch (8'-6") national interstate highway limits. Current problem that we are trying to solve is trailer weight and balance. The RV-12 trailers I have seen have the main gear and nose gear forward of the tandem axles. This adds 700+ pounds to the tongue weight. Only part of the (hung) wing weight would be aft of axles. I am investigating how the axles might be moved forward to better balance the loaded and unloaded trailer.

FYI the main gear is about 159-inches (13'-2-1/2") from the rear edge of the stabilator. I am not (yet) willing to buy a new truck to haul the RV-12 trailer so my tongue weight is limited to 1,200 pounds.

QUESTION: Anybody (hopefully a couple of anybodies) have handy the wheel weights from their aircraft weight and balance they are willing to post here?
Edit: I asked Van's Support for their data and sterling pointed out that ideally I need the wheel weights without the wings - in the configuration it will be inside the trailer. This is probably something most people do not have but just in case...
 
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QUESTION: Anybody (hopefully a couple of anybodies) have handy the wheel weights from their aircraft weight and balance they are willing to post here?

These are my weights by location full of fuel, just as one might do when en-route to the airport to go flying:

Nose Gear: 133
Left Main: 397
Right Main: 396
 
I am investigating how the axles might be moved forward to better balance the loaded and unloaded trailer.

DBRuth has a very elegant solution of simply loading the airplane backwards.

This allows the aircraft CG to sit right on top of the axle, hugely reducing the tongue weight.

This also makes the overall arrangement far more compact, which further reduces the gross weight of the trailer.

His trailer uses a drop tongue arrangement with a channel on the tongue for the nose wheel to roll on.
 
Drop Tongue RV-12 Trailer

DBRuth's trailer sounds ingenious and patent-worthy! Hope he might share a photo of his rig! Thanks to all. :)
 
A 800 pound airplane with its center of mass 3 feet forward of the trailer axle does not add 700 pounds to the tongue that is 10 feet ahead of the axle. Typically the tongue weight should be 10 - 15% of the total trailer weight.
 
Preliminary Trailer Plan Image Attached

I am hoping the trailer factory can work with me on the weight and balance, moving axle positions forward based on the attached image with approximate wheel loads of the airplane. Not accounting for wings off the airplane supported on floor, on walls or hung from ceiling yet. Custom door width not shown yet.
 

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Stuart -- Be sure to get real-world dimensions for the width of the main landing gear. When we loaded my RV-12 onto a car trailer for initial transport to the airport this outer gear width was the critical dimension - it was a very close fit between the tires' outer surfaces and the trailer's inner wheel fenders. Dimensional factors to be considered include: 1) the wheels' positive camber resulting from the lightly-weighted fuselage, 2) tire pressure and design, and 3) presence of wheel pants or wheel pant mounting hardware. A custom trailer should be able to accommodate these clearances.
 
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The stabilator will need to be supported so that the tips don’t touch sidewall of trailer. When trailer is in motion there will undoubtedly be lots of side motion (envision a horse being trailered). Makes me think about SB 16-08-01 regarding the stabilator bearings, VA-146, moving within their housings enough to cause interference between the inboard stabilator skin and the tail-cone fairing. This service bulletin instructs owners/operators to check for lateral stabilator movement prior to each flight and to correct the problem if it is found.

Even if ends of stabilator are cushioned against sidewall of trailer, the side motion of tail-cone during transport will put significant lateral force on the stabilator bearings...
 
DBRuth's trailer sounds ingenious and patent-worthy! Hope he might share a photo of his rig! Thanks to all. :)

I am the one that was taking pictures that day:
 

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Trailer pics

This is the kind of publicity that makes people 😁. Thanks for posting these pictures, sure look better than most of mine. It also answers the question How do you afford an airplane? Cause I tow it with a 29 year old truck 🤔 , and I don't have hangar rent.
 
RV-12 Trailers

DBRuth's rig seems like the ultimate short-haul solution. Thanks for sharing!
Old Photo-Bucket photos on this subject dissolved long-ago.

I hope to be on the road with the airplane for months at a time. I sincerely appreciate the dialogue and suggestions. The space between the trailer wheels is one of the things I am working on. Removable inside fenders help and I will use 205 trailer tires (narrower) rather than standard 225's and may do wheel spacers to move them out another inch or two. From what I have seen, main wheel fairings and fairing brackets will not fit in this type of trailer. I have them but won't use them.

As far as bracing the tail and other parts of the airplane, I am confident that can be solved if have an inside clear dimension of 8"-2" for the stabilator. Stabilator tip fairings won't fit but someday I might try to make tips that are easily removable. I have already made an adjustable tail stand using some plywood from the finish crate and 2-inch extruded polystyrene that I hot-knifed to wrap around the bottom of the tail cone at the F-1210 bulkhead. The stand fits tight with felt padding and conforms to the shape and if it doesn't seem safe enough I will make a better one. I hope that with the right fitments and right-sized trailer torsion axles if things don't hit, the ride the will be no worse than bumpy air or bumpy landings. Others have trailered without damage.
 

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The concern for inertial loads imparted into the structure during towing should be taken seriously. As long as the airplane is sitting on its landing gear and NOT clamped firmly to the trailer anywhere else, there is probably enough "suspension" provided by the gear and tires to protect the structure from fatigue loads.

But if you restrain the fuselage to the trailer near the tail, you risk introducting inertial loads. Yes they are probably comparable to a hard landing, but whereas the tail might feel 2000 bumps from landings in its lifetime, it may get that many bumps from a trailer in an hour.

Here is an example from the sailplane world. Sailplanes usually go in the trailer with the tail wheel (or tail skid) in a depression in the floor of the trailer, then a strap over the tail boom to hold it down. The rudder has mass-balance weights attached to the leading edge of the rudder, so it weighs perhaps 6--8 lbs. During trailering, vertical motions of the trailer put vertical loads into the rudder hinges, which might otherwise be designed to just withstand flight loads. In at least one high-performance sailplane, there was an AD to remove the lower rudder hinge and weld reinforcements onto it because they were cracking due to cyclic vertical loading while trailering. The lesson was learned and modern gliders have the lower rudder hinge built very stout to withstand trailering loads.

There would of course be significant lateral loads as well. The RV-12 has already had issues with fatigue of the stabilizer counterbalance arm. Trailering could significantly aggravate that, as well as other parts of the structure, if the fuselage is 'clamped' to the trailer near the tail.
 
To build on Steve’s thoughts…..there is a trailer designed for the Subsonex (for airshow guys that want to transport instead of flying lots of short cross-country legs), and the jet is loaded on a cart within the trailer to keep the “road loads” off the landing gear. Admittedly, its apples and oranges to the RV-12 gear - and for short distances, it probably doesn’t make much difference - but for long-distance transport, its something to think about.
 
Road Shock

The concern for inertial loads imparted into the structure during towing should be taken seriously. As long as the airplane is sitting on its landing gear and NOT clamped firmly to the trailer anywhere else, there is probably enough "suspension" provided by the gear and tires to protect the structure from fatigue loads.

....But if you restrain the fuselage to the trailer near the tail, you risk introducing inertial loads. Yes they are probably comparable to a hard landing, but whereas the tail might feel 2000 bumps from landings in its lifetime, it may get that many bumps from a trailer in an hour...

There would of course be significant lateral loads as well. The RV-12 has already had issues with fatigue of the stabilizer counterbalance arm. Trailering could significantly aggravate that, as well as other parts of the structure, if the fuselage is 'clamped' to the trailer near the tail.

Excellent points to consider! Thank you Steve! I just did the stabilator counterbalance reinforcing earlier this week and still have to do the stabilator front spar reinforcing as I am about to attach those for the first time.

Based on what you are saying it might help to have a reinforcing collar that holds the stabilator, anti-servo tab, fin and rudder together so the hinges are not taking loads and then support the collar with some degree of shock absorbing ability so vibrations are not fully transferred from the trailer.

I have studied two enclosed trailers. The first supported the stabilator within two well-padded shelves that were attached to the side walls of the trailer. The second trailer had the airplane only supported by the landing gear. I believe the well-padded shelves in David Kroner's trailer worked for him during his travels.

There are many details to test out and it seems that I should expect a lot of wear and tear that may not be obvious and very careful condition inspections will be needed after travel legs and unavoidable bumpy roads.

Edit: I should say I already did the landing gear reinforcing (mandatory and optional) and will look at having cushioned pads for the wheels to rest on.
 
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David Kroner's Trailer Tail Support

We see further "standing on the shoulders of giants" - Issac Newton
Lots of giants on the Van's Air Force Forums.

Found some photos of David Kroner's trailer tail support system which are attached. I feel very lucky that he so carefully thought through his design and has shared it. He apparently uses various foam cushions (of different densities?) to dampen vibrations. He also attaches the tail tiedown ring to a rubber block. He does not use a stand like what I made for my build.

A collar that takes load off the stabilator and rudder like what DBRuth uses on his trailer as seen in a recent photo posted in this thread by MechaSteve is also a good idea.

I am continuing to work with the trailer company and now have a drawing showing that the airplane and its wings will fit in one of their "stock" 20 FOOT +small V-nose aluminum car haulers with a custom rear ramp door. I am trying to get them to shift the tandem axles and the side door forward and will post a plan once I get their feedback.
 

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Trailer Feedback

Have gotten lots of good feedback on trailers for aircraft in this thread and offline with MM Fabrication who built a bunch of glider trailers and a special trailer for a huge, lightweight, fragile Google UAV. I looked at air suspension systems for the trailer and all the off-the-shelf stuff (such as Timbren) is for heavier trailers. Current thinking is to do homemade "three-point" air-suspension for the airplane wheels and resilient multi-layer-density foam-bungee mounts for the wings. MM said that the Torsion Axles give a worse ride than properly-sized leaf springs with the right shocks and airbags. The trailer manufacturers all want to bolt-on what they know so any suspension changes would have to be after purchase.

Good news on the 20-foot enclosed trailer weight and balance! The engineering department ran the numbers based on the trailer plan and loading shown in the attached drawing. The maximum fully loaded tongue weight is 725 pounds and the empty trailer (shell) is expected to be no more than 3,000 pounds. My maximum loaded fully fitted-out configuration will be 5,300 pounds or less. This is very towable by my old 3/4-ton truck, fully-loaded with my lightweight pop-up camper over the truck bed. The bad news is the all-aluminum semi-custom trailer will be very expensive even before the inside fit-out.
 

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Worth the Cost?

So how much are we talking about?
(We could deduct hangar rent!)

:D

Hi Tim,

I do not have the final quote yet but it will be north of $30K. When I started looking at trailers for an RV-12 back in 2016 I saw "steelies" made for aircraft going for about $8K. I could still get a custom steel-framed trailer for about 40% less than the all-aluminum one I am working on.

I am willing to pay the price for aluminum for a number of reasons. I am planning to drive cross-country, coast to coast, north and south towing it behind my 2003 (well-maintained) 2500HD, so I hope the reduced weight will be easier on fuel, brakes and transmission. The steel-framed trailers I have seen left outdoors in humid Florida are almost all rusted and leaky after about 5 years. The trailer I am looking at has a 10-year warranty and a "hole-less" roof.

I may have a way to safely store the trailer and airplane so they are protected from the elements in the future, but to start they will live outside in the sun, rain and wind. Feel free to send me a PM for info on trailer options I have looked at.
 
Thinking of getting an RV-12 Trailer?

If you have looked through this forum thread and are interested in purchasing a compact aluminum trailer that can hold an RV-12, now (August 2023) is a good time to do it. I am definitely trying to get one made and I have gotten PM's from two other people who are interested. The manufacturer would prefer to build 3 or 4 instead of doing just one "line buster" that screws up their factory production. I am expecting high-quality but it will cost more than $30K plus fit-out. This is for a trailer suitable for long cross-country towing not primary use as portable hanger. Send me a PM.
 
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