depends

That will depend partly on the vehicle, and partly on the viewer.  I would tend to notice how the vehicles were a bit oversized, if it's vehicles I know well.  Also, something like a wagon comes in different sizes anyway, so might be fine.  But a car I see all the ime might well look too big to me.  There's no one right answer. 

As I write this, I'm working on a 1/76 scale tank for an HO flatcar--14% oversized.  But, a Great War tank is huge anyway, and not a vehicle most people know well, so I suspect that it will look fine.

At 1:72, you are looking at being 20% oversized--put a couple on the layout and see how they look.  I can almost gaurantee that they'll look off if pout too close to a 1:87 vehicle...

Why

Given the large number of HO vehicles available, why use 1/72?

Since you're dealing in 3 dimensions the 1/72 will be 1.76 times the size of HO.  How well it works depends on the vehicle and how close it is to HO objects that will give it away. 

OTOH if having everything the same scale isn't very important to you, you can probably arrange a scene where it looks just fine even though it's oversized.

Good luck

Paul

The reason being

Walther's DC-3/C47 kit is rarer than rocking horse dung

Try an Arsenal

This Arsenal DC3 on eBay says it's made from an ex-Walthers mold, and there are two available.  There are also other Arsenal kits with different decals found with a Google search.

Regards,

Dave

?

They're not THAT big.

Of course, a bigger worry will be fitting the tank onto the wagon.

http://www.rmweb.co.uk/community/index.php?/topic/74216-wdlr-at-battle-of-cambrai/page-2

Also, it doesn't have to be near any other vehicles or buildings to look out of place - when a Land Rover truck is blocking two lanes, the game is already up. The only ones who can't see that would be the gamers who think a based 28mm figure has miraculously changed scales and end up putting VW Sciroccos onto the tabletop for their modern zombie or anti-terrorist scenarios which have the footprint of an M3 Bradley.

To use the items for forced perspective, you are going to have to design the scene carefully so the viewer can only see from within the arc in which it makes visual sense. A series of Space Battleship Yamato/Starblazers ships was once released using the principle to ensure that they looked, from a certain angle, just like they did in the cartoon - from dead ahead; from the side, however, they looked absolutely ridiculous. It's not the same as when you deliberately put a TT building up the back of a HO layout to create a sense of depth; putting a much larger scale model in the front to do so limits the viewing angle.

I tried using 1/72 models on my HO layout years ago...

After finally finding HO scale models of the same type as my 1/72 models it made my railroad look too much like a toy train set when using 1/72 vehicles and kind of Cartoon like using them with HO scale trains. 

If you want to use a tank on your RR I would look into Mini-Tanks on e-bay you can find hundreds of them in HO scale. But after my experience with 1/72 on a 1/87 trains Thirty years ago I would never use over size Vehicles again myself.

But as they say to each his own so, you do what you want, after all it is your Railroad and if you like the look who's to say it's not right.  

...

1:72 or 1:76 vehicles, no - just flat out no except construction equipment.  No matter what you do with them, they will be too big.

1:72 boats, you may have some leeway, but you'll want to rebuild the railings and likely scrape off all doors and use smaller doors via castings or shapes.

1:72 planes, you Might be able to get away with it.

...

1:72 or 1:76 vehicles, no - just flat out no except construction equipment.  No matter what you do with them, they will be too big.

1:72 boats, you may have some leeway, but you'll want to rebuild the railings and likely scrape off all doors and use smaller doors via castings or shapes.

1:72 planes, you Might be able to get away with it.

Tanks a lot

There's plenty of HO scale tanks to be had--but they're all these tanks that aren't even a pencil line on a drawing board.  Now that I have the tank built, it clearly is too large.  The sponsons would have to be removed or, in some cases, retracted for transport anyway, and I was going to build it like that.

perspective

If you have a place where the larger model can be placed in foreground with the railroad farther back it would work as forced perspective, slightly smaller models could likewise be used in the far background in a similar manner....DaveB

Revell DC-3

Look for the Revell DC-3.  It was 1/90 scale, so very close.  It's out of production, but easier to find than the Walthers kit.

1/72 with 1/87?

Depends on era, but in the 40s, 50s, 60s some European and especially British agricultural machinery; ploughs, tractors, combine harvesters, farm trailers etc were somewhat smaller than US equivalents so I/72nd/1/76th looks OK on 1/87th. I have an Intermountain 50' flat car (1/87th Southern Railway) with two 1/76th scale British agricultural ploughs and they look fine. Similar story with industrial machinery for building sites and road maintenance, but "ordinary" road vehicles, cars, buses, trucks, will look somewhat wrong.

Revell and some Japanese companies used to do 1/100th scale aircraft kits, and many years ago so did the British company.FROG. There are some new companies doing near 1/100th scale aircraft kits for wargaming

1/72 Vehicles

One very good reason to make use of a 1/72 model is for parts. Dragon makes a great US WWII jeep. It happens to have wheels that are very close to the correct size for a civilian Jeep FC-170 from the 1960's. It also has a nice shovel and steering wheel, seats etc. (In the case of the FC-170 you will need to build it as the EKO model is pretty small for HO). Another vehicle Dragon makes that has some nice wheels and tires is the German 8-Rad armored car series. It has wheels that are the correct size and deep-dished shape for a track inspection vehicle. Many wheel tire combinations are simply not available in 1/87 models and 1/72 is a possible source for a few of those.

perspective again

For years (late 60's early 70's), here in Australia it was very difficult and expensive to obtain, locally, HO vehicles.

For photo purposes, I always placed the 1/72/76 vehicles right in the foreground and my HO models behind them.  This was years before forced perspective was normally used. Mind you I was only using an "Insta-matic" 126 camera. At the time they look great, however these photos today look like @%$#^ compared to my new digital S.L.R. 

I will never be a John Allen or  Jim Boyd, but I keep trying.